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Atlantic salmon (Salmo salar) are found in a range of locations along Sweden's coastline, but Sweden's largest lake, Vänern, also harbors a population of salmon; the rare freshwater migratory form. The majority of the salmon in Lake Vänern migrate upstream in River Klarälven in order to spawn, where they are assisted by humans through the "trap and transport" method to get past Klarälven's eight hydropower dams, which otherwise constitute definite obstacles to upstream migration. When the salmon later migrate downstream to Lake Vänern they receive no assistance and experience a high mortality rate as they are partially forced to swim through the turbines. The wild salmon population today includes over 1000 spawners annually, an increase from <200 in the 196os, but far below historic records of over 10,000 spawners. This report therefore aimed to investigate the population growth rate and extinction risk for the salmon in Klarälven, both in the current situation and with passages installed past the hydropower plants, and in doing so answer the questions 1) How large is the population growth rate and risk of extinction for today’s population of salmon in Klarälven over the course of 100 years? and 2) How would passage solutions past the hydropower plants in Klarälven affect the population growth rate and risk of extinction for today’s population of salmon in Klarälven over the course of 100 years? These questions were answered by running a population viability analysis in the program Extinction Vortex, which allows the programming of model populations and the manipulation of parameters to test different scenarios. The scenarios that were tested were 1) Scenario 1: Today's method with trap and transport and total lack of passages, 2) Scenario 2: Trap and transport continues, and downstream passages are installed past all eight power plants, and 3) Scenario 3: Upstream and downstream passages are installed past all eight power plants and trap and transport ceases. T, Laxen (Salmo salar) förekommer på flera håll längst Sveriges havskuster, men även Sveriges största insjö Vänern hyser en population av lax; den sällsynta sötvattensvandrande formen. Majoriteten av Vänerlaxarna migrerar upp för att leka i Klarälven, där de assisteras av människan genom metoden ”trap and transport” som tar dem förbi Klarälvens åtta vattenkraftverk vilka annars utgör definitiva vandringshinder. När laxen sedan ska ta sig tillbaka ner till Vänern får de ingen assistans, i stället tvingas de delvis simma genom turbinerna med stor dödlighet som följd. Laxpopulationen idag består av över 1000 lekande fiskar varje år, en ökning från <200 individer på 1960-talet, men långt under historiska siffror på över 10 000 lekande laxar. Detta arbete syftade därför till att undersöka populationsutvecklingen och utdöenderisken för Klarälvslaxen, såväl i nuläget som vid en installation av passager förbi kraftverken, och genom detta besvara frågeställningarna 1) Hur stor är populationsutvecklingen och utdöenderisken för dagens population av Klarälvslax över kommande 100 år? och 2) Hur skulle passagelösningar förbi vattenkraftverken i Klarälven påverka populationsutvecklingen och utdöenderisken för dagens population av Klarälvslax över kommande 100 år? Dessa frågeställningar besvarades med hjälp av en sårbarhetsanalys i programmet Extinction Vortex, som tillåter uppbyggandet av modellpopulationer och manipulation av parametrar för att testa olika scenarier. Scenarierna som testades var 1) Scenario 1: Dagens metod med trap and transport och total avsaknad av passager, 2) Scenario 2: Trap and transport fortsätter samt nedströmspassager installeras förbi alla åtta kraftverk, och 3) Scenario 3: Upp- och nedströmspassager installeras förbi alla åtta kraftverk och trap and transport upphör. Resultatet av sårbarhetsanalysen visade inte på någon utdöenderisk kommande 100 år, men en negativ trend för Klarälvslaxens långsiktiga populationsutveckling med dagens metod. Utvecklingen

The eurasian lynx (Lynx lynx) has a wide distribution and occurs in the palearctic region. In Europe, the lynx has been persecuted and exterminated from several of its natural distribution areas and has also been subject to persecution in Sweden, where a high hunting pressure led to a reduced population that almost went extinct. Today, the Swedish lynx population has recovered but is kept down by licensed hunting, which is strictly controlled due to the lynx's protection status. However, Sweden's government has backed a proposal for reduced protection that could potentially lead to higher hunting quotas and thus threaten the lynx's future, because of predators’ vulnerability to high hunting pressures and smaller populations’ vulnerability to stochastic events such as catastrophes. The purpose of this study was to investigate the development of the Swedish lynx population and how high the risk of extinction is now, with increased hunting quotas and if catastrophes would occur both with current hunting quotas and increased hunting quotas. Based on the purpose, the questions that were answered were the following: 1) What does the population development and extinction risk look like for the Swedish lynx population in the next 100 years with current hunting quotas? 2) How do higher hunting quotas affect the Swedish lynx population development and extinction risk in the next 100 years? 3) How would catastrophes with current hunting quotas and increased hunting quotas affect the Swedish lynx population development and extinction risk in the next 100 years? The questions were answered through a population viability analysis performed in Vortex 10 where four scenarios were created. In scenario 1, the null scenario, the Swedish lynx population development and extinction risk over 100 years were investigated in relation to current hunting quotas. In scenario 2, the Swedish lynx population development and extinction risk over 100 years were investigated in relation to current h, Det eurasiska lodjuret (Lynx lynx) har en vid utbredning och förekommer i den palearktiska regionen. Lodjuret har i Europa förföljts och utrotats från flera av dess naturliga utbredningsområden och även i Sverige har lodjuret varit utsatt för förföljelse där ett högt jakttryck ledde till en minskad population som nästan utrotades. Idag har den svenska lodjursstammen återhämtat sig men hålls nere genom licensjakt, som är strikt kontrollerad på grund av lodjurets skyddsstatus. Däremot har Sveriges regering ställt sig bakom ett förslag till minskat skydd som potentiellt kan leda till högre jaktkvoter och därmed hota lodjurets framtid eftersom rovdjur är sårbara för höga jakttryck, samt att mindre populationer är mer sårbara för slumpmässiga händelser såsom katastrofer. Syftet med arbetet var att undersöka den svenska lodjursstammens utveckling och utdöenderisk i nuläget, vid förhöjda jaktkvoter, samt om katastrofer skulle inträffa vid nuvarande jaktkvoter respektive förhöjda jaktkvoter. Utifrån syftet besvarades följande frågeställningar: 1) Hur ser populationsutvecklingen och utdöenderisken ut för den svenska lodjursstammen under kommande 100 år med nuvarande jaktkvoter? 2) Hur påverkar högre jaktkvoter den svenska lodjursstammens populationsutveckling och utdöenderisk under kommande 100 år? 3) Hur skulle katastrofer vid nuvarande jaktkvoter respektive förhöjda jaktkvoter påverka den svenska lodjursstammens populationsutveckling och utdöenderisk under kommande 100 år? Frågeställningarna besvarades genom en sårbarhetsanalys som utfördes i Vortex 10 där fyra scenarier skapades. I scenario 1, grundscenariot, undersöktes den svenska lodjursstammens populationsutveckling och utdöenderisk över 100 år i förhållande till nuvarande jaktkvoter. I scenario 2 undersöktes den svenska lodjursstammens populationsutveckling och utdöenderisk över 100 år i förhållande till nuvarande jaktkvoter och katastrofer. I scenario 3 undersöktes den svenska lodjursstammens populationsutveckling o

Great apes have long lives, grow slowly, and reproduce late in life. This evolved life-history pattern now threatens many extant populations. Novel anthropogenic threats occur in tandem with ecological and demographic variation, which can have lasting impacts on population growth rates. Grauer’s gorillas (Gorilla beringei graueri) are among the most critically endangered subspecies among the extant great apes but have been relatively understudied. These group-living primates are found in eastern Democratic Republic of the Congo, a region experiencing rapid forest loss resulting in small, isolated gorilla habitats. In this dissertation, I explored three aspects of gorilla biology. In Chapter 1, I studied the effects of seasonal changes in food availability on within-group social interactions. I found that Grauer’s gorillas exhibit group-level changes in how spread out they are when they are foraging compared to when they are resting. However, in line with previous socioecological predictions, gorillas appear to be highly tolerant of group members while foraging, despite seasonal changes in the types of foods they consume. In Chapter 2, I conducted an exploratory analysis of the population-level transmission of nematodes found in Grauer’s gorillas. I used molecular methods commonly employed by parasitologists to identify the diversity of gastrointestinal nematodes found in multiple social groups living in the same habitat. I found that two of the most common taxa exhibited limited population structure, suggesting that gene flow for these nematodes among social groups may be quite high. I also discuss other explanations for this pattern, including parasite life history and development, abiotic factors, host movement, as well as alternative hosts in the habitat. Finally, in Chapter 3, I examined the effects of demographic stochasticity on the growth rate of a small, at-risk gorilla population (with only 2 adult females) in Mount Tshiaberimu, Virunga National Park. I use

Greater gliders are experiencing widespread decline across their distribution. They are obligate cavity dependent folivores with poor thermotolerance and high susceptibility to fragmentation and fire. These characteristics put greater gliders at high risk of further decline and extinction. Conservation of all populations are crucial to the species’ persistence. One of these populations of greater gliders is found at Seven Mile Beach National Park (SMBNP), on the South Coast of New South Wales. This population is heavily isolated and is known to occur at low densities, which has resulted in their state listing as an endangered population. The viability of this population is currently unknown. Therefore, the aim of this thesis was to evaluate the status and viability of the SMBNP population of greater gliders to inform targeted conservation management strategies. A tool used to guide the conversation of native fauna is population viability analysis. However, the quality of a population viability analysis model is influenced by the accuracy of input parameters, particularly initial population size. The first part of this thesis was a study on the use of double observer distance sampling method, as it has been recommended as the most robust method for estimating greater glider population size. Thus, this methodology was first used to generate a more accurate population estimate of greater gliders compared to a past strip transect survey conducted in 2019. This thesis then also investigated the effectiveness of double observer distance sampling to guide future population viability modelling. Population estimates using the double observer method found 347 greater gliders at SMBNP at a density of 0.46 gliders per ha. This equated to 0.05 more gliders per ha than previous estimates. We also found that key assumptions would be violated if strip transects, or single observer distance sampling were to be used. Therefore, these results reinforced double observer distance sampli

Rats are among the worst invasive alien predators. They prey upon eggs, chicks, and sometimes adults of seabirds, leading to the decline of many populations. Rats have invaded 93% of the islands in the western Indian Ocean, which is an avian biodiversity hotspot. Europa Island, Mozambique Channel, is a major seabird breeding site, where at least 1,000,000 pairs bred at the end of 20th century, including the endemic white-tailed tropicbirds (Phaethon lepturus europae). This species and the red-tailed tropicbird (Phaethon rubricauda) are vulnerable to predation by black rat (Rattus rattus), barn owl (Tyto alba), and pied-crow (Corvus albus) on Europa Island. In this study, we estimate the current population sizes of these tropicbird species and their breeding success. The impact of predators on tropicbird nests was quantified with camera traps. Finally, we model the dynamics of these populations under three management scenarios (no action, complete rat eradication, and targeted control of rats around nests). In 2019, 1,027 pairs of redtailed and 100 pairs of white-tailed tropicbirds bred on Europa Island, which indicates an annual decline of 5% and 17% since 2009, respectively. Breeding success of red-tailed tropicbirds and white-tailed tropicbirds was extremely low (0.08 ± 0.07 and 0.06 ± 0.03 respectively). Rats were detected at most surveyed nests and were the main predators of eggs and chicks. Pied-crows and barn owls also depredated nests occasionally. Population viability analysis projected a local extinction in 32–85 years for the red-tailed tropicbird, and in 11–50 years for white-tailed tropicbirds without conservation intervention. The complete eradication of rats would result in a rapid recovery of both populations. Rat control around nests only would result in population recovery only if 74% of the nests of white-tailed and 63% of the nests of red-tailed tropicbirds are free of rats., Les rats font partie des prédateurs étrangers les plus invasifs. Ils se nourrissent d’oeufs, d’oisillons et parfois d'oiseaux de mer adultes, ce qui provoque le déclin de nombreuses populations. Les rats ont envahi 93 % des îles de l'ouest de l’océan Indien, qui est un haut lieu de biodiversité aviaire. L’île Europa, dans le canal du Mozambique, est un site majeur de reproduction des oiseaux, puisqu’au moins un million de couples s’y reproduisaient à la fin du XXe siècle, notamment le phaéton à bec jaune (Phaethon lepturus europae). Cette espèce, ainsi que le phaéton à brins rouges (Phaethon rubricauda) est vulnérable à la prédation par le rat noir (Rattus rattus), la chouette effraie(Tyto alba) et le corbeau-pie (Corvus albus) sur l’île Europa. Dans cette étude, nous estimons la taille des populations de ces espèces d'oiseaux tropicaux et le succès de leur reproduction. L’impact des prédateurs sur les nids de phaétons a été quantifié à l’aide de pièges photographiques. Enfin, nous modélisons la dynamique de ces populations dans trois scénarios de gestion (aucune action, éradication complète des rats et contrôle ciblé des rats autour des nids). En 2019, 1 027 couples de phaétons à brin rouge et 100 couples de phaétons à bec jaune se sont reproduits sur l’île Europa, ce qui correspond respectivement à un déclin annuel de 5 % et de 17 % depuis 2009. Le succès de la reproduction des phaétons à brin rouge et des phaétons à bec jaune était extrêmement faible (0,08 ± 0,07 et 0,06 ± 0,03 respectivement). Des rats ont été détectés autour de la plupart des nids surveillés et étaient les principaux prédateurs d’oeufs et d'oisillons. Les corbeaux-pie et les chouettes effraie détérioraient parfois également les nids. L’analyse de viabilité de la population projetait une extinction locale d'ici 32 à 85 ans pour le phaéton à brin rouge et d'ici 11 à 50 ans pour le phaéton à bec jaune sans intervention de conservation. L’éradication complète des rats entraînerait le rétablissement

The current extinction crisis requires effective assessment and monitoring tools. Genetic approaches are appealing given the relative ease of field sampling required to estimate genetic diversity characteristics assumed related to population size, evolutionary potential, and extinction risk, and to evaluate hybridization with non-native species simultaneously. However, linkages between population genetic metrics of diversity from survey-style field collections and demographic estimates of population size and extinction risk are still in need of empirical examples, especially for remotely distributed species of conservation concern where the approach might be most beneficial. We capitalized on an exceptional opportunity to evaluate congruence between genetic diversity metrics and demographic-based estimates of abundance and extinction risk from a comprehensive Multiple Population Viability Analysis (MPVA) in a threatened fish, the Lahontan cutthroat trout (LCT). We sequenced non-native trout reference samples and recently collected and archived tissue samples of most remaining populations of LCT (N = 60) and estimated common genetic assessment metrics, predicting minimal hybridization with non-native trout, low diversity, and declining diversity over time. We further hypothesized genetic metrics would correlate positively with MPVA-estimated abundance and negatively with extinction probability. We uncovered several instances of hybridization that pointed to immediate management needs. After removing hybridized individuals, cautious interpretation of low effective population sizes (2-63) suggested reduced evolutionary potential for many LCT populations. Other genetic metrics did not decline over time nor correlate with MPVA-based estimates of harmonic mean abundance or 30-year extinction probability. Our results demonstrate benefits of genetic monitoring for efficiently detecting hybridization and, though genetic results were disconnected from demographic as

Protected areas may be important refuges for large carnivores, but many are not large enough to sustain viable populations. Without sufficient dispersal between protected areas, large carnivore populations inside them are at risk of becoming genetically isolated and demographically vulnerable. In this study, we use the jaguar population in and around Emas National Park in the Brazilian Cerrado as a case study to evaluate the demographic sustainability of a large carnivore population within a small and potentially isolated protected area. We used camera trapping data and spatially explicit capture-recapture models to estimate density and corresponding population size of jaguars in Emas National Park. We then used a matrix-based age and sex structured stochastic population model to evaluate the demographic viability of jaguar populations across a range of population sizes, including those estimated for Emas. We detected 10 individual jaguars during our survey with a total of 74 detections. Our density estimation became unbiased using a buffer width of 30 km and produced a density of 0.17 jaguars per 100 km(2). The estimated population sizes of 10-60 animals suffered extinction risks of 70-90% without net immigration. However, only a low number of immigrants were required to suppress extinction risk towards zero. Our density estimate for jaguars was lower than in previous studies, and our simulations suggested that this population may have a substantial extinction risk. Ensuring dispersal and connectivity outside of protected areas, through the implementation of habitat corridors, can greatly reduce this extinction risk, and we suggest that this scenario is potentially applicable to many other large carnivore populations.

Spatially explicit population models (SEPMs) can simulate spatiotemporal changes in species' range dynamics in response to variation in climatic and environmental conditions, and anthropogenic activities. When combined with pattern-oriented modelling methods, ecological processes and drivers of range shifts and extinctions can be identified, and plausible chains of causality revealed. The open-source multi-platform R package poems provides functionality for simulating and validating projections of species' range dynamics using stochastic, lattice-based population models. Built-in modules allow parameter uncertainty to propagate through to model simulations, with their effects on species' range dynamics evaluated using Approximate Bayesian Computation. These validation procedures identify models with the structural complexity and parameterisation needed to simulate the effects of past changes in climate, environment and human activities on species' range shifts and extinction risk. We illustrate the features and versatility of poems by simulating the historical decline and extinction of the Thylacine Thylacinus cynocephalus, an icon of recent extinctions in Australia. We show that poems can reveal likely ecological pathways to extinction using pattern-oriented methods, providing validated projections of the range collapse and population decline of threatened species. By providing flexible and extendable modules for building and validating SEPMs of species' range dynamics, poems allows the effects of past and future threats on species' populations to be quantified using well-parameterised, structurally realistic models, with important generative mechanisms. Since poems can directly unravel ecological processes of species responses to global change, and strengthen predictions of range shifts and extinction risk—within a flexible, R-based environment—we anticipate that poems will be of significant value to ecologists, conservation managers and biogeographers.

The marine environment is heavily affected by fishing pressure and knowing how different management strategies affect the persistence of marine species is crucial for ensuring sustainable fishing. Models used within the fisheries management strategies evaluation context have been implemented in the past decades from traditional single species methods to an ecosystem-based approach, but there are still uncertainties on the effectiveness of these models. This thesis aims to understand the drivers of marine species persistence coupling network-based methods and spatially explicit population viability analyses (PVA). This thesis focuses on marine species of south-eastern Australian waters, a region characterised by rich biodiversity and oceanographic complexity, supporting important Australian commercial fisheries sectors. PVA is an approach not yet widely investigated in the context of fisheries management strategies evaluation, however understanding species viability and ensuring metapopulation persistence is fundamental to avoid overexploitation of the stocks. In this thesis is examined how spatially explicit PVA compares to other commonly used models, demonstrating that PVA is a powerful alternative, suitable to inform fisheries management. PVA is applied to estimate metapopulation persistence in a spatial context, analysing how persistence changes when modelling alternative fisheries management scenarios for important commercial fisheries species. The knowledge of species distribution is very important for any spatially explicit population modelling and is needed when studying population viability and dynamics. A recent challenge in understanding and predicting species’ distributions has been focused on the influence of population connectivity. This thesis explores how to integrate graphbased metrics, representative of seascape connectivity, into marine-based species distribution models (SDMs) to understand the contribution of connectivity to predict marine species

Biodiversity is declining globally, with habitat clearing playing a major role in perpetuating these declines. Offsets aim to achieve no net loss of biodiversity by implementing conservation actions that deliver equal biodiversity gains to those lost through development. Broad habitat-based biodiversity metrics are commonly used to quantify development impacts and assign offset requirements. However, it is unclear what reliance on habitat-based offset metrics means for biodiversity long-term. In this thesis I explore the current state of biodiversity metrics within the scientific literature and how these metrics are applied in policies around the world. I also quantitatively test nine biodiversity metrics and explore the long-term ramifications of their use in offsetting on species persistence. In a sample of 255 publications from ecology (n = 158), conservation planning (n = 54), and offsetting (n = 43), I identify 24 categories of metrics used to quantify biodiversity. The offsetting literature focused largely on habitat attributes and area-based approaches for measuring biodiversity. Similarly, consistent use of habitat attributes, habitat condition, and area in 21 offset policies demonstrates that offsets do not adequately capture individual species or communities. Many offset policies measure species presence, however, less than half of those I reviewed measured any species-specific attributes which could be used to help inform conservation actions for those species. These two reviews demonstrate that the metrics currently used to measure biodiversity don’t reflect some of the key biodiversity attributes offsets aim to protect. To understand the long-term consequences of relying on such habitat-based metrics for offsetting I developed a spatial simulation tool and present a methodological framework that quantitatively tests the effects of metric choice on long-term persistence. The R-based simulation tool uses raster data to simulate development impacts and res

Both climate change and land use regimes affect the viability of populations, but they are often studied separately. Moreover, population viability analyses (PVAs) often ignore the effects of large environmental gradients and use temporal resolutions that are too coarse to take into account that different stages of a population's life cycle may be affected differently by climate change. Here, we present the High-resolution Large Environmental Gradient (HiLEG) model and apply it in a PVA with daily resolution based on daily climate projections for Northwest Germany. We used the large marsh grasshopper (LMG) as the target species and investigated (1) the effects of climate change on the viability and spatial distribution of the species, (2) the influence of the timing of grassland mowing on the species and (3) the interaction between the effects of climate change and grassland mowing. The stage- and cohort-based model was run for the spatially differentiated environmental conditions temperature and soil moisture across the whole study region. We implemented three climate change scenarios and analyzed the population dynamics for four consecutive 20-year periods. Climate change alone would lead to an expansion of the regions suitable for the LMG, as warming accelerates development and due to reduced drought stress. However, in combination with land use, the timing of mowing was crucial, as this disturbance causes a high mortality rate in the aboveground life stages. Assuming the same date of mowing throughout the region, the impact on viability varied greatly between regions due to the different climate conditions. The regional negative effects of the mowing date can be divided into five phases: (1) In early spring, the populations were largely unaffected in all the regions; (2) between late spring and early summer, they were severely affected only in warm regions; (3) in summer, all the populations were severely affected so that they could hardly survive; (4) between l

Protected areas may be important refuges for large carnivores, but many are not large enough to sustain viable populations. Without sufficient dispersal between protected areas, large carnivore populations inside them are at risk of becoming genetically isolated and demographically vulnerable. In this study, we use the jaguar population in and around Emas National Park in the Brazilian Cerrado as a case study to evaluate the demographic sustainability of a large carnivore population within a small and potentially isolated protected area. We used camera trapping data and spatially explicit capture‐recapture models to estimate density and corresponding population size of jaguars in Emas National Park. We then used a matrix‐based age and sex structured stochastic population model to evaluate the demographic viability of jaguar populations across a range of population sizes, including those estimated for Emas. We detected 10 individual jaguars during our survey with a total of 74 detections. Our density estimation became unbiased using a buffer width of 30 km and produced a density of 0.17 jaguars per 100 km2. The estimated population sizes of 10–60 animals suffered extinction risks of 70–90% without net immigration. However, only a low number of immigrants were required to suppress extinction risk towards zero. Our density estimate for jaguars was lower than in previous studies, and our simulations suggested that this population may have a substantial extinction risk. Ensuring dispersal and connectivity outside of protected areas, through the implementation of habitat corridors, can greatly reduce this extinction risk, and we suggest that this scenario is potentially applicable to many other large carnivore populations.

Amphibians are the most threatened class of vertebrate in the world. Although a number of causes of the amphibian decline phenomenon are emerging, there is a need for robust demographic data to be able to monitor current and future threats such as climate change. Despite this, few studies on amphibians have the life‐history data available to undertake these analyses and fewer still have looked at the challenges to population viability posed by fragmentation—a feature inherent in agricultural landscapes where the matrix is highly modified. Our aim was to investigate the population viability of a large burrowing frog in an agricultural landscape. Specifically, we aimed to investigate the future persistence of populations under a range of scenarios including populations connected by various levels of dispersal and reduced rainfall. We used the life‐history parameters of Heleioporus albopunctatus, a frog species widely distributed in the extensively cleared agricultural regions of south‐western Australia. We investigated the viability of 24 partially connected populations under a range of scenarios using the program Vortex Version 10.1.6.0. Metapopulations were consistently more robust to extinction than isolated local populations. Both meta‐ and local populations were more susceptible to increases in age‐specific mortality rates than to variation in the estimated ability of H. albopunctatus to disperse between breeding ponds, the survival rate of dispersers, or the frequency of drought. Our results reinforce the importance of metapopulations for survival in fragmented landscapes and point to the need to manage amphibian breeding ponds across landscapes to ensure high survival rates, particularly for juveniles.

A large part of biodiversity theory is driven by the basic question of what allows species to coexist in spite of a confined number of niches. A substantial theoretical background to this question is provided by modern coexistence theory (MCT), which rests on mathematical approaches of invasion analysis to categorize underlying mechanisms into factors that reduce either niche overlap (stabilizing mechanisms) or the average fitness differences of species (equalizing mechanisms). While MCT has inspired biodiversity theory in the search for these underlying mechanisms, we feel that the strong focus on coexistence causes a bias toward the most abundant species and neglects the plethora of species that are less abundant and often show high local turnover. Given the more stochastic nature of their occurrence, we advocate a complementary cross‐level approach that links individuals, small populations, and communities and explicitly takes into account (1) a more complete inclusion of environmental and demographic stochasticity affecting small populations, (2) intraspecific trait variation and behavioral plasticity, and (3) local heterogeneities, interactions, and feedbacks. Focusing on mechanisms that drive the temporary coviability of species rather than infinite coexistence, we suggest a new approach that could be dubbed coviability analysis (CVA). From a modeling perspective, CVA builds on the merged approaches of individual‐based modeling and population viability analysis but extends them to the community level. From an empirical viewpoint, CVA calls for a stronger integration of spatiotemporal data on variability and noise, changing drivers, and interactions at the level of individuals. The resulting large volumes of data from multiple sources could be strongly supported by novel techniques tailored to the discovery of complex patterns in high‐dimensional data. By complementing MCT through a stronger focus on the coviability of less common species, this approach can hel

The periodicity of life-cycle events (phenology) modulates host availability to pathogens in a repeatable pattern. The effects of sexual differences in host phenology have been little explored in wildlife epidemiological studies. A recent series of ranavirosis outbreaks led to serious declines of Boscas’ newt populations at Serra da Estrela (Portugal). The peculiar phenology of this species, in which a large number of females remain in the aquatic habitat after the breeding season, turns it into a suitable model to test how sex-biased mortality can affect host population persistence in the context of infectious diseases. We investigated how the phenology of Bosca’s newt (i.e. biased number of females) mediated the impact of Ranavirus. We then evaluated the risk of extinction of the population under different scenarios of sex-biased mortality using a population viability analysis. Two newt populations (one subject to yearly outbreaks and a comparative site where outbreaks have not been recorded) were tracked for trends over time following emergence of ranaviral disease, allowing us to assess the differential impact of the disease on both sexes. In addition to a signi ficant decline in abundance of adult newts, our data suggest that phenology can affect disease dynamics indirectly, leading to reduction in females and a reversal of the sex ratio of the breeding population. Our models suggest that female-biased mortality does not exacerbate Ranavirus-driven population declines in the short-term, but is likely to have a deleterious impact during the recovery process once the lethal effect of disease is removed from the system.

There is an ever increasing and bewildering array of statistical and mathematical modeling techniques in conservation management of terrestrial wildlife. These quantitative techniques have been utilized mostly for wildlife management in North America and Europe, but are increasingly applied to African species including cheetah (Acinonyx jubatus). Cheetah conservation managers frequently have to make decisions based on sparse information that may be of varying quality. Analyzing data, drawing inferences, and choosing between different management options can be daunting tasks. In this chapter we review some of the more popular and emerging quantitative approaches and discuss how they might be employed to address key cheetah conservation aims.

The conservation of threatened species requires an understanding of their ecology to identify the factors that are contributing to their decline and to assess their extinction risk. The objective of this thesis was to examine the ecology of Astelia australiana, a threatened herb endemic to Victoria, Australia to inform its conservation management. To achieve this objective, I examined how the distribution and abundance of A. australiana has changed over its entire known range in the 20- year period since its demographic monitoring program began. I also examined its habitat niche and regeneration ecology and response to potential threats including drought, wildfire, disease and low light availability. I then used this new understanding to develop a population viability model to explore the viability of A. australiana to current conditions, threats and limitations. The key findings of my research include a better understanding of the regeneration ecology of A. australiana including that it involves both sexual and asexual reproduction which occur at the same time. This reproduction occurs once in an individual’s lifetime and results in the production of flowers and fruit and three clones. Previously A. australiana had been variously described as dioecious and gynodioecious; however, it is trioecious, having male, female and hermaphrodite flowers on different plants and male and hermaphrodite flowers on the same plants. Various native bird and mammal species are involved in the regeneration ecology of A. australiana as pollinators and dispersers of fruit. Reproduction of A. australiana requires a minimum amount of available light from canopy gaps in the rainforest understorey to occur. A. australiana has declined in abundance by 57% over the 20-year period. Herbivory, and disease have contributed to mortality of A. australiana over this period but do not appear to be the only factors contributing to the observed decline. Although, A. australiana was found to be highly

Translocations to restore populations of endangered species are an important conservation tool, but a reliable diagnosis is needed to assess their success. We used capture-recapture modeling to analyze the adult apparent survival of released and resident tortoises in two translocation projects in Spain monitored for 14 and 29 years. We tested if long-term survival rates differ between released and resident individuals, if survival was lower during the phase of establishment (i.e. release cost), how long acclimation lasts and if increased density due to releases affects survival. We found lower survival of released tortoises during the phase of establishment (1 to 3 years) when residents were already present. After establishment, survival was very high and unaffected by density-dependence. Body condition before release was similar between recaptured and dead/missing tortoises, and did not predict establishment survival. Stochastic population viability analysis showed that success when releasing small numbers of individuals strongly depends upon adult long-term survival. Release of small second batches of tortoises was not sensitive to a growing population, regardless of its release timing. Our results highlight long-term survival as crucial in translocation projects of long-lived species, invalidating short-term (first year) survival assessment, when survival release cost does not match long-term survival. A release cost of different duration should be included in model estimation before modeling predictions. Releasing tortoises (for welfare of captive individuals or for mitigating human negative impacts) in an already established population is not recommended under most circumstances. Acclimation cost is followed by survival approaching wild counterparts. If this milestone is not achieved, the project needs to be carefully assessed to adopt other management options or should be stopped altogether.

Habitat fragmentation is a common problem in relation with road infrastructure which leads to mortality, isolation of animal populations, and has a negative effect on biodiversity. Animal crossings have been implemented in many countries and are a useful tool to mitigate these problems but they are expensive to build. This thesis explores the methodological approaches used to evaluate how wildlife crossings’ functions are evaluated. This was done by reviewing abstracts from a total of 223 peer-reviewed scientific publications. There were a great variety of methods used to evaluate crossing, but cameras was the most commonly used. Many studies used a combination of methods to make up for shortcomings with the single methods, for example, using PIT to make up for cameras inability to identify individuals crossing the passage. The results show that it is important to evaluate the passages and associated structures, like fences, for many factors and not focus on only one. Cameras are a good option for monitoring the use of a passage, but it is key to understand that animals using the passage does not equal a positive effect on their populations. It is therefore important to evaluate how populations are affected and whether they are viable or not. This was done by using Population Viability Analysis, evaluating populations’ genetic variation, or evaluate whether the passage allows for gene flow to occur. DNA-analysis is sometimes required for this and can now be done with a more inexpensive and simple method, using hairs from animals, collected in a non-invasive way. It is also important to evaluate the passage both before and after to be able to determine the actual effect the passage has had. But nothing ever stays the same, and the passage should be monitored for longer periods or at regular intervals to make sure a satisfactory effect is sustained., Vägar är en onekligen central del i vårt globala samhälle. De betyder kontakt och förflyttning för oss, men för djuren är dem ofta hinder vilket kan leda till att habitat fragmenteras och att djur isoleras. När djuren isoleras kan de inte nå nya resurser eller nya habitat, eller hitta en partner. Detta kan innebära att djuren får sämre överlevnadschanser och svårare att fortplanta sig. I värsta fall kan hela populationer dö ut ifall det t.ex. förekommer för mycket inavel eller om de drabbas av katastrofer. Det finns många sätt att avhjälpa problem som orsakas av vägar, ett är att bygga broar och andra passager så att djuren kan korsa vägarna på ett säkert sätt. Det är dock dyrt att bygga dessa och det därför är det viktigt att de fungerar. Om de inte förbättrar situationen är det bättre att spara pengarna och hitta andra lösningar. I detta arbete presenterar jag material från 223 vetenskapliga publikationer som beskriver hur man utvärderar djurpassager. Det finns flera olika metoder som används för att utvärdera djurpassager. En vanlig metod är att avgöra ifall antalet viltolyckor minskar efter att passagen byggts, men för att avgöra ifall djur använder passagen, användes framförallt kameror men även analys av spår lämnade av djur. Med både kameror och spåranalys kan man få data över vilka arter som använder passagen och hur ofta. Med kameror kan man även få data över ifall djur använder passagen i grupper, kön och ålder på individer, och djurs beteende, t.ex. ifall de är rädda för att använda passagen. Kameror kräver mindre arbete än spåranalys, och kan göras året runt, men är dyra att köpa in. Spåranalys är därför billigare vid korta studier, medan kameror billigare för längre studier. För att avgöra hur en passage har påverkat populationer krävs andra metoder än kameror och spåranalys. Man kan t.ex. använda telemetri, vanligtvis GPS, för att ta reda på hur djur förflyttar sig och ifall de når passagen inom sitt hemområde. Med GPS kan man även ta reda på ifall ide

Conservation planning and biodiversity assessments need quantitative targets to optimize planning options and assess the adequacy of current species protection. However, targets aiming at persistence require population-specific data, which limits their use in favor of fixed and non-specific targets, likely leading to unequal distribution of conservation efforts among species. Here we propose a method to derive equitable population targets, which are quantitative targets of population size that ensure equal probabilities of persistence across a set of species, and can be easily inferred from species-specific traits. We applied population dynamics models across a range of life-history traits representative for mammals, and estimated minimum viable population targets intrinsically related to species body mass. Our approach provides a compromise between pragmatic non-specific targets, and detailed context-specific estimates of population viability for which only limited data is available. It enables a first estimation of species-specific population targets based on a readily available trait, and thus allows setting equitable targets for population persistence in large-scale and multispecies conservation assessments and planning.

Population viability analysis (PVA) is a reliable tool for ranking management options for a range of species despite parameter uncertainty. No one has yet investigated whether this holds true for model uncertainty for species with complex life histories and for responses to multiple threats. We tested whether a range of model structures yielded similar rankings of management and threat scenarios for 2 plant species with complex postfire responses. We examined 2 contrasting species from different plant functional types: an obligate seeding shrub and a facultative resprouting shrub. We exposed each to altered fire regimes and an additional, species-specific threat. Long-term demographic data sets were used to construct an individual-based model (IBM), a complex stage-based model, and a simple matrix model that subsumes all life stages into 2 or 3 stages. Agreement across models was good under some scenarios and poor under others. Results from the simple and complex matrix models were more similar to each other than to the IBM. Results were robust across models when dominant threats are considered but were less so for smaller effects. Robustness also broke down as the scenarios deviated from baseline conditions, likely the result of a number of factors related to the complexity of the species' life history and how it was represented in a model. Although PVA can be an invaluable tool for integrating data and understanding species' responses to threats and management strategies, this is best achieved in the context of decision support for adaptive management alongside multiple lines of evidence and expert critique of model construction and output.

© The Author(s), 2017. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Ecosphere 8 (2017): e01653, doi:10.1002/ecs2.1653., Humans have altered nearly every natural disturbance regime on the planet through climate and land-use change, and in many instances, these processes may have interacting effects. For example, projected shifts in temperature and precipitation will likely influence disturbance regimes already affected by anthropogenic fire suppression or river impoundments. Understanding how disturbance-dependent species respond to complex and interacting environmental changes is important for conservation efforts. Using field-based demographic and movement rates, we conducted a metapopulation viability analysis for piping plovers (Charadrius melodus), a threatened disturbance-dependent species, along the Missouri and Platte rivers in the Great Plains of North America. Our aim was to better understand current and projected future metapopulation dynamics given that natural disturbances (flooding or high-flow events) have been greatly reduced by river impoundments and that climate change could further alter the disturbance regime. Although metapopulation abundance has been substantially reduced under the current suppressed disturbance regime (high-flow return interval ~ 20 yr), it could grow if the frequency of high-flow events increases as predicted under likely climate change scenarios. We found that a four-year return interval would maximize metapopulation abundance, and all subpopulations in the metapopulation would act as sources at a return interval of 15 yr or less. Regardless of disturbance frequency, the presence of even a small, stable source subpopulation buffered the metapopulation and sustained a low metapopulation extinction risk. Therefore, climate change could have positive effects in ecosystems where disturbances have been anthropogenically suppressed when climatic shifts move disturbance regimes toward more historical patterns. Furthermore, stable source populations, even if unintentionally maintained through anthropogenic activities, may be critical for the persisten, Nebraska Environmental Trust Nebraska State Wildlife Grant Program; Nebraska Wildlife Conservation Fund; U.S. Army Corps of Engineers; U.S. Fish and Wildlife Service (USFWS); USFWS North Atlantic Landscape Conservation Cooperative; Virginia Tech

Modellering av populationer kan vara till stor hjälp för bevarandebiologin i form av att hjälpa till att utvärdera en potentiell respons hos populationer vid olika hypotetiska åtgärder. En mer effektiv naturvård kan således utvecklas med hjälp av de resultat som modelleringar ger. Denna studie presenterar resultaten av modelleringar för hypotetiskt minskad mortalitet i olika livsstadier för den sjövandrande populationen lax i Klarälven. Modellerna är utformade i programmet Vortex. De olika scenarier som modellerats skiljer sig åt i överlevnadsfrekvenser hos olika åldersgrupper hos laxen. Även en modellering på den potentiella betydelsen av kelten gjordes, då kelten troligtvis kan komma att ha stor påverkan på populationsstorleken. Denna studie visar på att minskad mortalitet på smolt vid smoltvandring och detta i kombination med ökad habitat kvalitet och kvantitet hade stor påverkan på populationsstorleken mot det grundscenario som uppvisar hög mortalitet. Trots detta var risken för en utdöd population inom 50 år fortsatt relativ stor och var 37 %. Idag leker laxen endast en gång under sin livstid i Klarälven. När laxen fick en simulerad chans att leka en extra gång under sin livstid, genom en ökad livslängd på ett år, reducerades risken för en utdöd population inom 50 år till endast 2 %., The modeling of populations can be a great help for conservation biology in terms of helping to evaluate a potential response in populations to different hypothetical conservation measures. A more effective conservation approach can thus be attained with help from the results shown in the models. This study presents the results of modelling for hypothetically reduced mortalities at different life stages for the lake migrating population salmon in Klarälven. The models were developed in the program Vortex. The different scenarios that have been simulated differ in the mortality rates for different age classes within the salmon population. A simulation on the importance of kelt was also done, because the kelt can have a potentially big impact on population growth. This study shows that reduced mortalities during smolt migration in combination with an increase in habitat quality and quantity, had a significant effect on the population size compared with the scenario with relatively high mortality rates. Even though the population size was considerably higher for this scenario, the probability for the population to go extinct in the next 50 years was still relatively high at 37 %. Today the salmon only spawn once in their lifetime in the River Klarälven. When the salmon were given the opportunity to spawn one extra time, by prolonging their lifespan by one year, the probability of extinction in the next 50 years was reduced to only 2 %.

In order to predict species response to climate and land-use change, numerically fast and easily applicable assessment tools for species survival are required. We present a set of formulae to calculate the mean lifetime of a metapopulation in a spatially heterogeneous and dynamic landscape subject to habitat patch diminution, loss and/or spatial shift of the habitat network. The formulae require as inputs (i) information about the number, location and size of the habitat patches for several time steps to quantify landscape dynamics in terms of patch destruction, diminution or shifting rates and (ii) data on species traits such as their vulnerability to environmental variation and their dispersal ability to quantify local colonisation and extinction rates. We validate the formulae with a spatially explicit simulation. The analysis is complemented by a protocol for the easy use of the approach and practical application examples. A software implementation is available on request from the authors.

Humans have altered nearly every natural disturbance regime on the planet through climate and land-use change, and in many instances, these processes may have interacting effects. For example, projected shifts in temperature and precipitation will likely influence disturbance regimes already affected by anthropogenic fire suppression or river impoundments. Understanding how disturbance-dependent species respond to complex and interacting environmental changes is important for conservation efforts. Using field-based demographic and movement rates, we conducted a metapopulation viability analysis for piping plovers (Charadrius melodus), a threatened disturbance-dependent species, along the Missouri and Platte rivers in the Great Plains of North America. Our aim was to better understand current and projected future metapopulation dynamics given that natural disturbances (flooding or high-flow events) have been greatly reduced by river impoundments and that climate change could further alter the disturbance regime. Although metapopulation abundance has been substantially reduced under the current suppressed disturbance regime (high-flow return interval similar to 20 yr), it could grow if the frequency of high-flow events increases as predicted under likely climate change scenarios. We found that a four-year return interval would maximize metapopulation abundance, and all subpopulations in the metapopulation would act as sources at a return interval of 15 yr or less. Regardless of disturbance frequency, the presence of even a small, stable source subpopulation buffered the metapopulation and sustained a low metapopulation extinction risk. Therefore, climate change could have positive effects in ecosystems where disturbances have been anthropogenically suppressed when climatic shifts move disturbance regimes toward more historical patterns. Furthermore, stable source populations, even if unintentionally maintained through anthropogenic activities, may be critical for the

Translocations to restore populations of endangered species are an important conservation tool, but a reliable diagnosis is needed to assess their success. We used capture-recapture modeling to analyze the adult apparent survival of released and resident tortoises in two translocation projects in Spain monitored for 14 and 29 years. We tested if long-term survival rates differ between released and resident individuals, if survival was lower during the phase of establishment (i.e. release cost), how long acclimation lasts and if increased density due to releases affects survival. We found lower survival of released tortoises during the phase of establishment (1 to 3 years) when residents were already present. After establishment, survival was very high and unaffected by density-dependence. Body condition before release was similar between recaptured and dead/missing tortoises, and did not predict establishment survival. Stochastic population viability analysis showed that success when releasing small numbers of individuals strongly depends upon adult long-term survival. Release of small second batches of tortoises was not sensitive to a growing population, regardless of its release timing. Our results highlight long-term survival as crucial in translocation projects of long-lived species, invalidating short-term (first year) survival assessment, when survival release cost does not match long-term survival. A release cost of different duration should be included in model estimation before modeling predictions. Releasing tortoises (for welfare of captive individuals or for mitigating human negative impacts) in an already established population is not recommended under most circumstances. Acclimation cost is followed by survival approaching wild counterparts. If this milestone is not achieved, the project needs to be carefully assessed to adopt other management options or should be stopped altogether.

It has been proposed that in slow-growing vertebrate populations survival generally has a greater influence on population growth than reproduction. Despite many studies cautioning against such generalizations for conservation, wildlife management for slow-growing populations still often focuses on perturbing survival without careful evaluation as to whether those changes are likely or feasible.Here, we evaluate the relative importance of reproduction and survival for the conservation of two bottlenose dolphin (Tursiops cf aduncus) populations: a large, apparently stable population and a smaller one that is forecast to decline. We also assessed the feasibility and effectiveness of wildlife management objectives aimed at boosting either reproduction or survival. Consistent with other analytically based elasticity studies, survival had the greatest effect on population trajectories when altering vital rates by equal proportions. However, the findings of our alternative analytical approaches are in stark contrast to commonly used proportional sensitivity analyses and suggest that reproduction is considerably more important. We show that1.) in the stable population reproductive output is higher, and adult survival is lower;2.) the difference in viability between the two populations is due to the difference in reproduction;3.) reproductive rates are variable, whereas survival rates are relatively constant over time;4.) perturbations on the basis of observed, temporal variation indicate that population dynamics are much more influenced by reproduction than by adult survival;5.) for the apparently declining population, raising reproductive rates would be an effective and feasible tool to reverse the forecast population decline; increasing survival would be ineffective.Our findings highlight the importance of reproduction – even in slow-growing populations – and the need to assess the effect of natural variation in vital rates on population viability. We echo others in cauti

Many threatened and invasive species occupy collections of spatially separated populations subject to local extinction and colonisation, known as metapopulations. Although they occur naturally, metapopulations are becoming increasingly prevalent throughout the world due to habitat loss and fragmentation. To increase the persistence of threatened metapopulations, or decrease the persistence of invasive ones, managers must decide how, where and when to spend limited resources across space and time. In this thesis, I integrate quantitative models with decision theory to predict the persistence of metapopulations in response to management alternatives. This thesis is divided into six chapters. The first chapter provides a general introduction to metapopulations and decision theory. The second chapter explores when, where and how to manage threatened metapopulations when the dynamics of these networks are poorly understood. Adaptive management has been applied to ecological problems containing considerable uncertainty, but is yet to guide the restoration of metapopulations. I develop a framework to optimally manage metapopulations using adaptive management when there is uncertainty in the rate of colonisation between patches. I develop a case study for the threatened bay checkerspot butterfly (Euphydryas editha bayensis) and demonstrate how best to manage the population while learning about its dynamics over time. The third chapter examines when to add a patch to a threatened metapopulation to compensate for destruction of another due to urbanisation or agricultural development. I develop spatially explicit metapopulation models for two threatened Australian species – the growling grass frog (Litoria raniformis) and the southern emu-wren (Spititurus malachurus intermedius) – and determine when it is optimal to add a patch to each metapopulation if the budget available to managers accrues interest over time. I find that there are many occupancy states of each metapopulati

Background: Many species are distributed as metapopulations in dynamic landscapes, where habitats change through space and time. Individuals locate habitat through dispersal, and the relationship between a species and landscape characteristics can have profound effects on population persistence. Despite the importance of connectivity in dynamic environments, few empirical studies have examined temporal variability in dispersal or its effect on metapopulation dynamics. In response to this knowledge gap, we studied the dispersal, demography, and viability of a metapopulation of an endangered, disturbance-dependent shorebird. We examined three subpopulations of piping plovers (Charadrius melodus) on the lower Platte and Missouri rivers from 2008–2013. High flow events from an upstream dam on the Missouri River in 2010 and 2011 allowed us to assess the effect of total habitat loss and the subsequent creation of new habitat associated with a large disturbance at one ‘natural’ study location. The other two sites within the metapopulation, which were maintained by anthropogenic activities (e.g., mining, development, habitat restoration), were largely unaffected by this disturbance, resulting in a controlled natural experiment. Results: High flow events were associated with increased emigration, decreased immigration, and decreased survival in the subpopulation that experienced high flows. Following the high flow event, immigration into that subpopulation increased. Dispersal rates among subpopulations were negatively correlated with distance. The metapopulation had a low probability of extinction over 100 years (0 %) under the current disturbance interval and associated dispersal and survival rates. However, persistence depended on relatively stable, human-created habitats, not the dynamic, natural habitat (47.7 % extinction probability for this subpopulation). Conclusions: We found that functional connectivity, as measured by the rate of dispersal among subpopulations, in

Many threatened species in human-dominated systems are managed through conservation programs. Such programs are sometimes designed based on intuition or short-term results rather than assessing their long-term biological and economic sustainability. The current conservation program for Montagu's harriers Circus pygargus, a ground-nesting bird of prey, in Lleida (Catalonia, NE Spain) aims to protect nests located in farmlands by promoting crop harvest delay around the nest and compensating farmers for their economic loss. This program has been flagged as a ‘conservation trap’ as its costs have been increasing over time, possibly compromising the long-term sustainability of the program and associated consequences to the local harrier population. In the present work, population viability analyses (PVA) were used to find a conservation management scenario that decreases the risk of the conservation trap, or at least minimizes the medium-term expenditure on conservation. PVA simulations suggest that the current nest protection program is financially unsustainable at the medium-term. Cost-effectiveness analyses suggest that it would be impossible to fully avoid the conservation trap if the conservation goal is to maintain Lleida's current population size. Alternative management scenarios that minimize the medium-term expenditure of scarce conservation funds are presented. The results suggest that selecting a conservation program based only on short-term biological or cost-effective targets might not be the most appropriate, and demonstrate the relevance of having clear medium-term conservation targets.

Forecasting population persistence in environments subjected to periodic disturbances represents a general challenge for ecologists. In arid and semiarid regions, climate change and human water use pose significant threats to the future persistence of aquatic biota whose populations typically depend on permanent refuge waterholes for their viability. As such, habitats are increasingly being lost as a result of decreasing runoff and increasing water extraction. We constructed a spatially explicit population model for golden perch Macquaria ambigua (Richardson), a native freshwater fish in the Murray-Darling Basin in eastern Australia. We then used the model to examine the effects of increased aridity, increased drought frequency, and localized human water extraction on population viability. Consistent with current observations, the model predicted golden perch population persistence under the current climate and levels of water use. Modeled increases in local water extraction greatly increased the risk of population decline, while scenarios of increasing aridity and drought frequency were associated with only minor increases in this risk. We conclude that natural variability in abundances and high turnover rates (extinction/recolonization) of local populations dictate the importance of spatial connectivity and periodic cycles of population growth. Our study also demonstrates an effective way to examine population persistence in intermittent and ephemeral river systems by integrating spatial and temporal dynamics of waterhole persistence with demographic processes (survival, recruitment, and dispersal) within a stochastic modeling framework. The approach can be used to help understand the impacts of natural and anthropogenic drivers, including water resource development, on the viability of biota inhabiting highly dynamic environments.

Global biodiversity is fundamental for human welfare as ecosystem services, agricultural crops, and even human health depend on its preservation. Identifying strengths and shortcomings of current conservation risk assessment practices is of great importance given the current biodiversity crisis. Population viability analyses (PVA) are quantitative tools used to perform such risk assessments by modeling population dynamics. Variation in PVAs includes the type of population model used and the quantity and quality of the data available to parameterize the models. In this dissertation, I use computer simulations to evaluate the performance of two commonly used models (Matrix and Scalar) that have different data requirements. The first study evaluates the combined effects of environmental variability, measurement error and data quantity on the percent population decline estimates generated using matrix and scalar PVA for two different life histories. It was observed that measurement error has a stronger detrimental effect on projected decline than data quantity. Additionally, scalar models projected declines quite well relative to matrix models. The latter tend to be over-precautionary. The second study expanded the findings from the first by evaluating if the same results hold on a widely used decision-making framework—Red List Category of the International Union for the Conservation of Nature (IUCN). Results supported previous conclusions and provided evidence that scalar models can successfully be used in conservation decision-making with moderate levels of variability and uncertainty. The third study evaluates the reliability of population decline projections and their subsequent use in the Red List in the face of variability and uncertainty across life histories with different generation times. It was observed that increments in generation time could either increase or decrease the reliability of model predictions depending on the underlying growth rate. Specificall

Patch-mosaic burning is a widely accepted practical approach to managing biodiversity, whereby spatial and temporal diversity of fire is manipulated to benefit biotic diversity. We use simulation experiments based on stochastic population viability analysis to evaluate the implications of contrasting patch-mosaic burning scenarios for the population dynamics and risk of decline of four species of small mammals in northern Australia. Our results, based on models developed from detailed mark-recapture data, suggest that fire frequency has more influence on small-mammal persistence than fire extent. Risk of extinction increased for all four species when fire frequency exceeded once every five years. Under current ambient fire regimes most Australia tropical savannas burn more frequently and therefore seem to have unfavourable consequences for this faunal group and risk precipitating severe future declines.

As reptile populations worldwide decline, construction and monitoring of road mortality mitigation measures is becoming common. I studied the effectiveness of barrier fencing at preventing Eastern Massasauga rattlesnakes (Sistrurus catenatus) from gaining access to the road. I also tested whether ecopassages were effective at allowing Massasaugas to access habitat on both sides of the road. I determined that there was a reduction of Massasaugas on the road post-installation of barrier fencing. Data from various monitoring approaches showed that Massasaugas do indeed use the ecopassages to cross the road. I quantified the long-term effect of mitigation structures on the population viability of Massasaugas. A Population Viability Analysis revealed that post-mitigation construction, the study population has a low probability of extinction, suggesting that mitigation is effective at promoting a sustainable population. Analyzing the effects of road mortality at the population level is crucial to ensure that decision makers are adequately informed of the status of species-at-risk.

Despite recent efforts to develop the science of reintroduction biology, there is still no general and broadly accepted definition of reintroduction success. We investigate this issue based on the postulates (1) that successful reintroduction programs should produce viable populations and (2) that reliable assessments of ultimate success require that populations have reached their regulation phase. We assessed if the viability of these reintroduced populations could be evaluated using the same criteria as for remnant populations, such as the Internation Union for Conservation of Nature (IUCN) Red List criteria. Using modeling, we projected the viabilities of theoretical populations with various life history and environmental characteristics and we tested whether population sizes (criterion D of the IUCN) and other potential predictors are relevant proxies of the risk of extinction (criterion E of the IUCN) in the case of remnant populations with an unknown past history and in the case of reintroduced populations that have reached their carrying capacity. We found that, as for remnant populations, population size can be used as a relevant indicator (although subject to considerable uncertainty) of the viability of reintroduced populations. However, the results demonstrate the importance of the reintroduction failure filter, that is, the fact that the reintroduced populations that have successfully reached their carrying capacity are those with the highest and more stable growth rates, especially if populations have been reintroduced with a few individuals. As a consequence, the general relationship between the current size of a population and its projected viability will, most likely, differ considerably between remnant and reintroduced populations. Overall, our results demonstrate that there are no theoretical limitations on the application of some of the criteria widely used for remnant populations to define reintroduction success, although these criteria are very

Context Increasing the amount of green infrastructure, defined as small-scale natural landscape elements, has been named as a climate adaptation measure for biodiversity. While green infrastructure strengthened ecological networks in some studies, it is not known whether this effect also holds under climate change, and how it compares to other landscape adaptation options. Objectives We assessed landscape adaptation options under scenarios of climate change for a dispersal-limited and climate-sensitive species: great crested newt, Triturus cristatus. Methods A spatially-explicit modelling framework was used to simulate newt metapopulation dynamics in a case study area in the Netherlands, under alternative spatial configurations of 500 ha to-be-restored habitat. The framework incorporated weather-related effects on newt recruitment, following current and changing climate conditions. Results Mild climate change resulted in slightly higher metapopulation viability, while more severe climate change (i.e. more frequent mild winters and summer droughts) had detrimental effects on metapopulation viability. The modelling framework revealed interactions between climate and landscape configuration on newt viability. Restoration of ponds and terrestrial habitat may reduce the negative effects of climate change, but only when certain spatial requirements (habitat density, connectivity) as well as abiotic requirements (high ground water level) are met. Conclusions Landscape scenarios where habitat was added in the form of green infrastructure were not able to meet these multiple conditions, as was the case for a scenario that enlarged core areas. The approach allowed a deduction of landscape design rules that incorporated both spatial and abiotic requirements resulting in more effective climate adaptation options.

The Minimum Area Requirements (MAR) of species is a concept that explicitly addresses area and therefore can be highly relevant for conservation planning and policy. This study compiled a comprehensive database of MAR estimates from the literature, covering 216 terrestrial animal species from 80 studies. We obtained estimates from (a) Population Viability Analyses (PVAs) which explored a range of area-related scenarios, (b) PVAs that provided a fixed value – either MAR or the minimum viable population size (MVP) alongside other area-relevant information, and (c) empirical studies of occupancy patterns in islands or isolated habitat patches across area. We assessed the explanatory power of life-history traits (body mass, feeding guild, generation length and offspring size), environmental variables (average precipitation and temperature), research approach and phylogenetic group on MAR estimates. PVAs exploring area showed strong correlation between MAR and body mass. One to two additional variables further improved the predictive power. PVA reporting fixed MAR, and occupancy-based studies, were better explained by the combination of feeding guild, climatic variables and additional life history traits. Phylogeny had a consistent but usually small contribution to the predictive power of models. Our work demonstrates that estimating the MAR across species and taxa is achievable but requires cautious interpretation. We further suggest that occupancy patterns are likely sensitive to transient dynamics and are therefore risky to use for estimating MAR. PVA-based evaluations enable considering time horizon and extinction probability, two aspects that are critical for future implementation of the MAR concept into policy and management.

[EN]: Many threatened species are conserved and managed following conservation programs. These conservation programs are usually developed by intuition without assessing their biological and long-term economic sustainability. As a result, many of these programs may operate more as conservation traps rather than as conservation solutions. The current conservation program of Montagu`s harrier (Circus pygargus), a ground-nesting bird of prey, in Catalonia (NE Spain) aims to protect nests located in farmlands by delaying the harvest around the nest and compensating farmers for the economic loss associated to this measure. However, this conservation program has been flagged as a conservation trap due to the fact that its costs have been increasing over time, possibly compromising its long-term maintainability, but may need to be maintained indefinitely to have a long-term impact on the population; thus, the viability of the species is largely dependent on the duration of monetary incentives, which may be compromised. In the present work, population viability analyses were used in order to find a conservation management scenario that decreases the risk of a conservation trap, or at least minimizes the medium-term expenditure on conservation, considering simultaneously natural vegetation and agricultural breeding populations of Montagu’s harrier in Catalonia. The results hereby presented demonstrate that if the conservation goal is to maintain a self-sustainable population, it might be possible to avoid the conservation trap by increasing the population size of the natural vegetation breeding populations. However, if the conservation goal is to maintain also the agricultural breeding population, it would be impossible to fully avoid a conservation trap. Different management scenarios that might minimize the medium-term expenditure of scarce conservation funds are presented. The results obtained suggest that selecting a conservation program based only on biological or cost, [FR]: De nombreuses espèces menacées sont conservées et gérées suite aux programmes de conservation. Ces programmes de conservation sont généralement développés par intuition sans évaluer leur viabilité biologique et économique à long terme. En conséquence, plusieurs de ces programmes peuvent fonctionner comme des pièges de conservation plutôt que comme des solutions de conservation. Le programme actuel de conservation du busard cendré (Circus pygargus), une rapace nichant au sol, en Catalogne (NE Espagne), vise à protéger les nids situés dans les terres agricoles en retardant la récolte autour du nid, moyennant une indemnisation aux agriculteurs pour les pertes économiques. Cependant, ce programme de conservation a été marquée comme un piège de conservation en raison du fait que ses coûts ont augmenté au fil du temps, ce qui peut compromettre sa maintenance à long terme, mais doit être maintenu dans le temps pour avoir un effet a long-terme dans la population; donc, la viabilité de l´espèce peut être dépendant de la durabilité des budgets pour sa conservation. Dans le projet actuel, des analyses de viabilité de la population ont été utilisés afin de trouver un scénario de gestion de la conservation qui diminue le risque d'un piège de conservation, ou au moins de minimiser les dépenses à moyen terme, en tenant compte simultanément les populations reproductrices dans végétation naturelle et agricole du busard cendré dans Catalogne. Les résultats démontrent que si l'objectif de conservation est de maintenir une population autosuffisante au niveau régional, il pourrait être possible d'éviter le piège de la conservation en augmentant la taille des populations reproductrices en végétation naturelle. Toutefois, si l'objectif de conservation est aussi de maintenir les populations reproductrices agricoles, il serait impossible d'éviter totalement un piège de conservation. Différents scénarios de gestion qui pourraient réduire les dépenses des fonds de conservation à moyen t

Population viability analysis (PVA) has become a basic tool of current conservation practice. However, if not accounted for properly, the uncertainties inherent to PVA predictions can decrease the reliability of this type of analysis. In the present study, we performed a PVA of the whole western European population (France, Portugal, and Spain) of the endangered Bonelli's Eagle (Aquila fasciata), in which we thoroughly explored the consequences of uncertainty in population processes and parameters on PVA predictions. First, we estimated key vital rates (survival, fertility, recruitment, and dispersal rates) using monitoring, ringing, and bibliographic data from the period 1990-2009 from 12 populations found throughout the studied geographic range. Second, we evaluated the uncertainty about model structure (i.e., the assumed processes that govern individual fates and population dynamics) by comparing the observed growth rates of the studied populations with model predictions for the same period. Third, using the model structures suggested in the previous step, we assessed the viability of both the local populations and the overall population. Finally, we analyzed the effects of model and parameter uncertainty on PVA predictions. Our results strongly support the idea that all local populations in western Europe belong to a single, spatially structured population operating as a source-sink system, whereby the populations in the south of the Iberian Peninsula act as sources and, thanks to dispersal, sustain all other local populations, which would otherwise decline. Predictions regarding population dynamics varied considerably, and models assuming more constrained dispersal predicted more pessimistic population trends than models assuming greater dispersal. Model predictions accounting for parameter uncertainty revealed a marked increase in the risk of population declines over the next 50 years. Sensitivity analyses indicated that adult and pre-adult survival are the ch

Rad obuhvata modelovanje ekoloških niša dve vrste guštera Podarcis sicula i P. melisellensis na dva područja kopnene oblasti istočnog Jadrana povezane sa analizom rizika izumiranja metapoulacionih demografskih modela formiranih na osnovu prostornih niša. Obe vrste su su od opisivanja u XIX veku bile epizodično predmet zoogeografskih, ekoloških i evolucionih istraživanja u Jadranskoj oblasti. Brojni dosad prikupljeni bionomski i ekološki podaci o obe vrste na istraživanom području, međutim, uglavnom nisu stavljeni u celovit kvantitativni koncept, velikim delom ostajući na nivou manje ili više detaljnog kvalitativnog opisa. Postojeći kvantitativni podaci, prikazani su kao “lateralni” ili “akcesorni” rezultati istraživanja čiji je osnovni cilj bio sasvim drugačiji te je njihova upotrebna vrednost u potpunosti podređena kontekstu realizovanih istraživanja. Posebno se to odnosi na autekološka i populaciono-ekološka istraživanja. Ostrvske populacije su znatno bolje istražene od kopnenih. Realizujući kvantitativno modeliranje niša kopnenih populacija, pokušali smo da makar malo taj problem ublažimo. U modelovanju ekoloških niša korišćeno je 47 kvantitativnih i 9 kvalitativnih EGV, u zavisnosti od metode, koje su formirane na osnovu globalnih baza podataka. Obuhvaćena područja, oko 100 km2 po površini, nalazila su se u Poljicama (okolina Splita, Hrvatska) i šireg regiona Boke Kotorske (Crna Gora) na kojoj su detaljno mapirane obe vrste. Korišćene su tri metode sa prisustvom vrsta (P/O, ENFA, MaxEnt i GARP), četiri koje zahtevaju prisustva/odsustva (P/A, SpFA, PLS, GRM, DA), i tri koje mogu koristiti oba tipa podataka (P/O ili P/A, GAM, MARS, BRT). Na osnovu profila stanišne povoljnosti formirane su detaljne karte prostornih niša. Sve metode su identifikovale centre povoljnostog staništa istog ili sličnog položaja i obuhvata. P/A metode su identifikovale mnogo šire zone suboptimalnih staništa za obe vrste na oba područja. EGV korišćene za analizu su ocenjene po čestoći odabi, Ecological niche models were generated for two lizard species, Podarcis sicula i P. melisellensis, in two mainland areas of the eastern Adriatic, and coupled with spatially-explicit PVA based on habitat suitabilty profiles generated by ENM. Both species have, since their description in the XIX century, been episodically studied from zoogeographical, ecological, and evolutionary aspects. However, a wealth of bionomic data collected by investigators was qualitative, lacking a comprehensive quantitative framewok, and as such are of limited value. The available bionomic and ecological data was largely presented as "lateral" or "accessory" data collected for a different scientific objective, and their utility is largely determined by the context of that research. Specifically, that problem pertains to the utility of reported autecological and population-ecological data. Mainland populations of both species were also much less studied than the island populations in the Adriatic. We addressed this problem by conducting quantitative niche-modelling research based on the mainland. For ecological niche modelling we used 47 quantitative and 9 qualitative EGV's, depending on the method, which were generated from global datasets. Both regions were cc. 100 km2 in area, and were located in Poljice (Split, Croatia) and the general region of Boka Kotorska (Montenegro) for we had which detailed distribution data. Three methods requiring presence/only data were used (P/O, ENFA, MaxEnt i GARP), four requiring presence/absence (P/A, SpFA, PLS, GRM, DA), and three which could use both (P/O or P/A, GAM, MARS, BRT). Habitat suitability profiles generated by these methods were used to map the spatial niches. All methods identified identical or very similar core areas of HS. P/A methods were much more liberal in assigning adjacent suboptimal HS zones for both species in both areas. EGV's selected by the methods were scored by frequency of selection in models, and a minimal subset generating

Бела кања Neophron percnopterus (Aves: Accipitridae) је глобално угрожени, мали, опортунистички, моногамни, углавном солитарни и дугоживећи лешинар, распрострањен у јужним деловима Европе, Блиског Истока, Кавказа, централне Азије, Индије, и северне Африке, са светском популацијом од 13000-41000 адултних јединки. Популација у Европи броји око 3300-5050 парова. Глобална популација је забележила драматични пад, интензиван и у Европи, и већ је потпуно нестала са неких делова Балкана. У Европи се антропогени фактори, нарочито тровање, уништавање станишта, редукција извора хране и узнемиравање, сматрају за најозбиљније факторе угрожавања. Македонска популација белих кања је пала за око 86% у задње три декаде, и за безмало 50% током задњих 10 година, да би бројала само око 21 пар на почетку 2012. године. Зато, циљеви овог рада су: да се прикаже рецентна дистрибуција беле кање у Републици Македонији, да се анализира тренд популације и промене у просторној дистрибуцији парова и њихова густина гнежђења, да увид у репродуктивне параметре врсте, идентификују најзначајнији фактори за пад популације уз анализу фактора који утичу на опстанак територија и на праметре гнежђења. Исто тако, у циљу ефетивне заштите врсте, одређује се највероватна судбине популације беле кање у Македонији, утврђује се њен национални статус угрожености, и идентификују се најбоље мере заштите за очување ове врсте. Теренска истраживања су вршена у периоду 2003. - 2011. године, узимајући територију као јединицу посматрања да би се одредила величина и тренд популације. Просторне анализе су рађење у GIS-у, коришћењем χ2 за одређивање фрекфенције дистрибуције, G-статистике као меру равномерности дистрибуције гнезда и Mann-Whitney U-test за одређивање значајности тих промена, уз прорачунавање густине гнежђења. Гнездећи параметри (продуктивност популације, успех гнежђења и стопа пролетавања) су били праћени у периоду 2006. – 2011., а поређења између парова и година су урађена једнофакторском ANOVA-ом..., The Egyptian Vulture Neophron percnopterus (Aves: Accipitridae) is a globally endangered, small, opportunistic, monogamous, mostly solitary and long-lived vulture, distributed in the southern parts of Europe, the Middle East, Caucasus, Central Asia and north Africa, with global population of 13000-41000 adult individuals. The European population is estimated to 3300-5050 pairs. The global population experienced dramatic decline, intensive also in Europe, and has completely disappeared from some parts of the Balkan Peninsula. In Europe the anthropogenic factors, particularly poisoning, destruction of the habitats, food source reduction and disturbance are considered to be the most important factors leading to the decline. The Macedonian population of the Egyptian Vulture has declined for about 86% in the last three decades, and for almost 50% in the last 10 years, counting only about 21 pairs in the beginning of the 2012. Therefore, the goals of the present work are to show the recent distribution of the Egyptian Vulture in Macedonia, to analyse the population trend and changes in the spatial distribution of the breeding pairs and their breeding densities, to show the breeding parameters of the species, identify the most important factors leading to population decrease with analysis of the factors affecting territory persistence and breeding parameters. Aiming at more effective conservation of the species, this works points out the most probable destiny of the Egyptian Vulture in Macedonia, establishes its national conservation status and identifies the best conservation measures for its preservation. The field work was performed in the period 2003 - 2011, using territory as the observation unit in order to establish the size and the trend of the population. The spatial analyses were performed in GIS, using χ2 to determine the frequencies of the distribution, G-statistics as a measure of regularity of the nest distribution, and Mann-Whitney U-test to check for signif

Uncertainty associated with ecological forecasts has long been recognized, but forecast accuracy is rarely quantified. We evaluated how well data on 82 populations of 20 species of plants spanning 3 continents explained and predicted plant population dynamics. We parameterized stage-based matrix models with demographic data from individually marked plants and determined how well these models forecast population sizes observed at least 5 years into the future. Simple demographic models forecasted population dynamics poorly; only 40% of observed population sizes fell within our forecasts' 95% confidence limits. However, these models explained population dynamics during the years in which data were collected; observed changes in population size during the data-collection period were strongly positively correlated with population growth rate. Thus, these models are at least a sound way to quantify population status. Poor forecasts were not associated with the number of individual plants or years of data. We tested whether vital rates were density dependent and found both positive and negative density dependence. However, density dependence was not associated with forecast error. Forecast error was significantly associated with environmental differences between the data collection and forecast periods. To forecast population fates, more detailed models, such as those that project how environments are likely to change and how these changes will affect population dynamics, may be needed. Such detailed models are not always feasible. Thus, it may be wiser to make risk-averse decisions than to expect precise forecasts from models. Habilidad de los Modelos Matriciales para Explicar el Pasado y Predecir el Futuro de las Poblaciones de Plantas Resumen La incertidumbre asociada con el pronostico ecologico ha sido reconocida durante un largo tiempo pero rara vez se cuantifica su seguridad. Evaluamos que tan bien la informacion de 82 poblaciones de 20 especies de plantas a lo larg, AuthorCount:20

Studies explaining the choice of model structure for population viability analysis (PVA) are rare and no such study exists for butterfly species, a focal group for conservation. Here, we describe in detail the development of a model to predict population viability of a glacial relict butterfly species, Boloria eunomia, under climate change. We compared four alternative formulations of an individual-based model, differing in the environmental factors acting on the survival of immature life stages: temperature (only temperature impact), weather (temperature, precipitation, and sunshine), temperature and parasitism, and weather and parasitism. Following pattern-oriented modeling, four observed patterns were used to contrast these models: one qualitative (response of population size to habitat parameters) and three quantitative ones describing population dynamics during eight years (mean and variability of population size, and magnitude of the temporal autocorrelation in yearly population growth rates). The four model formulations were not equally able to depict population dynamics under current environmental conditions; the model including only temperature was selected as the most parsimonious model sufficiently well reproducing the empirical patterns. We used all four model formulations to test a range of climate change scenarios that were characterized by changes in both mean and variability of the weather variables. All models predicted adverse effects of climate change and resulted in the same ranking of mean climate change scenarios. However, models differed in their absolute values of population viability measures, underlining the need to explicitly choose the most appropriate model formulation and avoid arbitrary usage of environmental drivers in a model. We conclude that further applications of pattern-oriented modeling to butterfly and other species are likely to help in identifying the key factors impacting the viability of certain taxa, which, ultimately, wi

Aim: To quantify the consequences of major threats to biodiversity, such as climate and land-use change, it is important to use explicit measures of species persistence, such as extinction risk. The extinction risk of metapopulations can be approximated through simple models, providing a regional snapshot of the extinction probability of a species. We evaluated the extinction risk of three species under different climate change scenarios in three different regions of the Mexican cloud forest, a highly fragmented habitat that is particularly vulnerable to climate change. Location: Cloud forests in Mexico. Methods: Using Maxent, we estimated the potential distribution of cloud forest for three different time horizons (2030, 2050 and 2080) and their overlap with protected areas. Then, we calculated the extinction risk of three contrasting vertebrate species for two scenarios: (1) climate change only (all suitable areas of cloud forest through time) and (2) climate and land-use change (only suitable areas within a currently protected area), using an explicit patch-occupancy approximation model and calculating the joint probability of all populations becoming extinct when the number of remaining patches was less than five. Results: Our results show that the extent of environmentally suitable areas for cloud forest in Mexico will sharply decline in the next 70 years. We discovered that if all habitat outside protected areas is transformed, then only species with small area requirements are likely to persist. With habitat loss through climate change only, high dispersal rates are sufficient for persistence, but this requires protection of all remaining cloud forest areas. Main conclusions: Even if high dispersal rates mitigate the extinction risk of species due to climate change, the synergistic impacts of changing climate and land use further threaten the persistence of species with higher area requirements. Our approach for assessing the impacts of threats on biodiversit

Although reintroduction has been a widely implemented conservation tool,in many cases it is unclear whether the released animals can successfully establish aviable and self-sustaining population. We constructed a population model forreintroduced Sumatran orangutans (Pongo abelii) and conducted a population viabilityanalysis to evaluate the probability of persistence. We based our study on areintroduced orangutan population at Bukit Tigapuluh, Jambi, Central Sumatra,Indonesia. We used various scenarios to assess the effects of adaptation time, numberof released individuals, duration of release period, variation in infant survival, andcarrying capacity on population extinction probability over time. We found thatbehavioral adaptation of individuals to living in the wild within <6 yrs after releaseenhanced population persistence, and that initial losses may be compensated byadditional releases. Our analyses indicated that a lack of information about releasedorangutans prevented accurate evaluation of the effectiveness of reintroduction procedures.Consequently, we recommend that reintroduction projects improve dataquality on the fates of released individuals in order to provide a reliable basis for apopulation viability analysis. The use of population viability analyses would allowproactive management and a better evaluation of reintroduction progress.

AimMost risk assessments and decisions in conservation are based on surrogate approaches, where a group of species or environmental indicators are selected as proxies for other aspects of biodiversity. In the focal species approach, a suite of species is selected based on life history characteristics, such as dispersal limitation and area requirements. Testing the validity of the focal species concept has proved difficult, due to a lack of theory justifying the underlying framework, explicit objectives and measures of success. We sought to understand the conditions under which the focal species concept has merit for conservation decisions. LocationOur model system comprised 10 vertebrate species in 39 patches of native forest embedded in pine plantation in New South Wales, Australia. MethodsWe selected three focal species based on ecological traits. We used a multiple-species reserve selection method that minimizes the expected loss of species, by estimating the risk of extinction with a metapopulation model. We found optimal reserve solutions for multiple species, including all 10 species, the three focal species, for all possible combinations of three species, and for each species individually. ResultsOur case study suggests that the focal species approach can work: the reserve system that minimized the expected loss of the focal species also minimized the expected species loss in the larger set of 10 species. How well the solution would perform for other species and given landscape dynamics remains unknown. Main conclusionsThe focal species approach may have merit as a conservation short cut if placed within a quantitative decision-making framework, where the aspects of biodiversity for which the focal species act as proxies are explicitly defined, and success is determined by whether the use of the proxy results in the same decision. Our methods provide a framework for testing other surrogate approaches used in conservation decision-making and risk assessment.

Studies explaining the choice of model structure for population viability analysis (PVA) are rare and no such study exists for butterfly species, a focal group for conservation. Here, we describe in detail the development of a model to predict population viability of a glacial relict butterfly species, Boloria eunomia, under climate change. We compared four alternative formulations of an individual-based model, differing in the environmental factors acting on the survival of immature life stages: temperature (only temperature impact), weather (temperature, precipitation, and sunshine), temperature and parasitism, and weather and parasitism. Following pattern-oriented modeling, four observed patterns were used to contrast these models: one qualitative (response of population size to habitat parameters) and three quantitative ones describing population dynamics during eight years (mean and variability of population size, and magnitude of the temporal autocorrelation in yearly population growth rates). The four model formulations were not equally able to depict population dynamics under current environmental conditions; the model including only temperature was selected as the most parsimonious model sufficiently well reproducing the empirical patterns. We used all four model formulations to test a range of climate change scenarios that were characterized by changes in both mean and variability of the weather variables. All models predicted adverse effects of climate change and resulted in the same ranking of mean climate change scenarios. However, models differed in their absolute values of population viability measures, underlining the need to explicitly choose the most appropriate model formulation and avoid arbitrary usage of environmental drivers in a model. We conclude that further applications of pattern-oriented modeling to butterfly and other species are likely to help in identifying the key factors impacting the viability of certain taxa, which, ultimately, wi

The current study deals with the critically endangered limpet Patella ferruginea (Gastropoda: Patellidae) endemic to the western Mediterranean. The species has been in decline since the early 20th century and is currently restricted to certain locations on the Iberian Peninsula, Corsica, Sardinia, and the North African coasts of Morocco, Algeria, and Tunisia. Its large size and conspicuous shell often makes the species a target of human collection. We describe the results of temporal monitoring conducted on one of the remaining most important P. ferruginea populations in North Africa, and provide quantitative data on growth rates, natural mortality, and harvesting rates. The maximum collection rates were recorded during the summer months, when fishermen most attend the beach. This type of mortality mostly affected medium and large individuals, and increased natural mortality rates up to 37%. All results and previously available data were implemented for population viability analysis. We determined that the species is clearly overexploited in the study area, and may face local extinction within the next 20 y if harvesting activities are not controlled. Even though more precise predictions could be obtained by using a longer time series, our study is the first attempt to model the future viability of the species, and indicates the urgent need of establishing efficient protection measures.