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Copyright of Conservation Biology is the property of Wiley-Blackwell and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Variation in plant dispersal capabilities strongly influences the assembly of island plant communities. Many tropical plants have seeds capable of long‐distance, often oceanic, dispersal; in some cases, these taxa speciate into island interior endemics with reduced dispersal capabilities, though whether this is a general pattern is debated. Flotation times are highly variable among plants with oceanic dispersal and between such plants and their inland congeners. Here, we experimentally compared salt‐water flotation in three woody plant genera in Palau, Micronesia, comparing broadly distributed and island endemic species within each genus. The widespread Calophyllum inophyllum (with oceanic and vertebrate dispersal), C. soulattri (vertebrate dispersal), and Terminalia catappa had substantially longer flotation than their inland endemic relatives C. pelewense and T. crassipes. This supports the "Loss of dispersal ability" hypothesis for Calophyllum though, for Terminalia, additional phylogenetic information is needed to determine T. crassipes' sister species. Seed flotation in the widespread, oceanic dispersed Pandanus tectorius did not significantly differ from that of the Palau endemics P. palawensis and P. aimiriikensis. Our results highlight that differences among taxa in dispersal modes, speciation modes, and their interactions may influence the assembly of island floras. [ABSTRACT FROM AUTHOR]

The loss of large animals due to overhunting and habitat loss potentially affects tropical tree populations and carbon cycling. Trees reliant on large‐bodied seed dispersers are thought to be particularly negatively affected by defaunation. But besides seed dispersal, defaunation can also increase or decrease seed predation. It remains unclear how these different defaunation effects on early life stages ultimately affect tree population dynamics. We reviewed the literature on how tropical animal loss affects different plant life stages, and we conducted a meta‐analysis of how defaunation affects seed predation. We used this information to parameterize models that altered matrix projection models from a suite of tree species to simulate defaunation‐caused changes in seed dispersal and predation. We assessed how applying these defaunation effects affected population growth rates. On average, population‐level effects of defaunation were negligible, suggesting that defaunation may not cause the massive reductions in forest carbon storage that have been predicted. In contrast to previous hypotheses, we did not detect an effect of seed size on changes in seed predation rates. The change in seed predation did not differ significantly between exclosure experiments and observational studies, although the results of observational studies were far more variable. Although defaunation surely affects certain tree taxa, species that benefit or are harmed by it and net changes in forest carbon storage cannot currently be predicted based on available data. Further research on how factors such as seed predation vary across tree species and defaunation scenarios is necessary for understanding cascading changes in species composition and diversity. [ABSTRACT FROM AUTHOR]

Tropical regions are undergoing rapid land use change, with major implications for global biodiversity. Selective logging and agroforestry are particularly widespread across tropical forests, often occurring in close proximity. But while a number of studies have addressed their impacts separately, few have directly compared how they influence forest vertebrates. Here, we assessed the occurrence of medium‐ to large‐bodied mammals in logged forest, unlogged forest, and agroforestry areas in three study areas in interior Sarawak, Malaysian Borneo. We detected 34 species across 99 camera trap locations and used multi‐species occupancy models to estimate species‐specific occurrence while accounting for imperfect detectability, spatial autocorrelation, natural habitat heterogeneity, and metrics of site accessibility (distance to human infrastructure) as proxies for potential hunting pressure. We found that species occurrences were unaffected by the distance to the nearest road or village and only responded to elevation and the distance to the nearest river in a single species each. Detection rates tended to vary with micro‐habitat characteristics such as the size of tree stumps and the prevalence of trees and rattan palms, which are often not considered in camera‐based occupancy studies. Occurrence rates of five species varied across habitat types but were not detectably lower in agroforestry sites than in unlogged forest for any species. Our results indicate that without unsustainable hunting, agroforestry and logged forest provide usable habitat for some, though not all, rainforest mammals. We also suggest that camera trap studies may benefit from the incorporation of fine‐scale habitat information into detectability estimation. Abstract in Malaysian is available with online material. [ABSTRACT FROM AUTHOR]

Aim: For tens of millions of years, herbivorous megafauna were abundant across the globe, fulfilling important ecological roles including seed dispersal. Megafruits are very large fruits that are dispersed most effectively by megafauna. However, megafruits also occur in ecosystems where megafauna are extinct or were never present, emphasizing our incomplete understanding of megafauna–megafruit relationships. Here we use the complex biogeography of tropical Asia to investigate how megafruit diversity and traits are associated with the diversity of megafauna, smaller animals, and abiotic factors. Location: Tropical Asia, from the Indian subcontinent in the west to tropical China in the north to the Maluku archipelago (Indonesia) in the east. Time period: Late Pleistocene to the present day. Major taxa studied: Megafauna (body weight > 500 kg) that consume fruits, including stegodons, elephants, rhinoceroses, giant tapirs, and large bovids. Fleshy‐fruited plant species across the region with a fruit width > 40 mm (i.e., megafruits). Methods: We compiled a list of all megafruits along with selected plant, fruit, and seed traits in 16 subregions across tropical Asia. We explored biogeographical patterns in megafruit diversity and traits in relation to the diversities of past and present megafauna, large‐ and medium‐sized animals and abiotic factors (mean temperature, mean precipitation, precipitation seasonality, insularity). Results: We identified 496 megafruits in tropical Asia. Megafruit diversity was highest in subregions with high megafaunal diversity, particularly extant species. Megafruit traits were influenced most strongly by abiotic factors (mainly temperature and land area), and weakly by megafauna and smaller dispersers. Main conclusions: Our results are consistent with megafauna maintaining or responding to megafruit diversity, but variation in megafruit traits is primarily associated with abiotic factors. Given the massive megafaunal losses in tropical Asia since the Late Pleistocene, it is important to identify fruit traits that can increase megafauna‐dependence and thus vulnerability to these losses. [ABSTRACT FROM AUTHOR]

The establishment of protected areas (PAs) is a central strategy for global biodiversity conservation. While the role of PAs in protecting habitat has been highlighted, their effectiveness at protecting mammal communities remains unclear. We analyzed a global dataset from over 8671 camera traps in 23 countries on four continents that detected 321 medium‐ to large‐bodied mammal species. We found a strong positive correlation between mammal taxonomic diversity and the proportion of a surveyed area covered by PAs at a global scale (β = 0.39, 95% confidence interval [CI] = 0.19–0.60) and in Indomalaya (β = 0.69, 95% CI = 0.19–1.2), as well as between functional diversity and PA coverage in the Nearctic (β = 0.47, 95% CI = 0.09–0.85), after controlling for human disturbances and environmental variation. Functional diversity was only weakly (and insignificantly) correlated with PA coverage at the global scale (β = 0.22, 95% CI = −0.02–0.46), pointing to a need to better understand the functional response of mammal communities to protection. Our study provides important evidence of the global effectiveness of PAs in conserving terrestrial mammals and emphasizes the critical role of area‐based conservation in a post‐2020 biodiversity framework. [ABSTRACT FROM AUTHOR]

Conservation outcomes could be greatly enhanced if strategies addressing anthropogenic land‐use change considered the impacts of these changes on entire communities as well as on individual species. Examining how species interactions change across gradients of habitat disturbance allows us to predict the cascading consequences of species extinctions and the response of ecological networks to environmental change.We conducted the first detailed study of changes in a commensalist network of mammals and dung beetles across an environmental disturbance gradient, from primary tropical forest to plantations, which varied in above‐ground carbon density (ACD) and mammal communities.Mammal diversity changed only slightly across the gradient, remaining high even in oil palm plantations and fragmented forest. Dung beetle species richness, however, declined in response to lower ACD and was particularly low in plantations and the most disturbed forest sites. Three of the five network metrics (nestedness, network specialization and functionality) were significantly affected by changes in dung beetle species richness and ACD, but mammal diversity was not an important predictor of network structure. Overall, the interaction networks remained structurally and functionally similar across the gradient, only becoming simplified (i.e. with fewer dung beetle species and fewer interactions) in the most disturbed sites.We suggest that the high diversity of mammals, even in disturbed forests, combined with the generalist feeding patterns of dung beetles, confer resilience to the commensalist dung beetle–mammal networks.This study highlights the importance of protecting logged and fragmented forests to maintain interaction networks and potentially prevent extinction cascades in human‐modified systems. [ABSTRACT FROM AUTHOR]

Mitigating the massive impacts of defaunation on natural ecosystems requires understanding and predicting hunting effort across the landscape. But such understanding has been hindered by the difficulty of assessing the movement patterns of hunters in thick forests and across complex terrain. We statistically tested hypotheses about the spatial distribution of hunting with circuit theory and structural equation models. We used a data set of >7000 known kill locations in Guyana and hunter movement models to test these methods. Comparing models with different resistance layers (i.e., different estimates of how terrain and land cover influence human movement speed) showed that rivers, on average, limited movement rather than serving as transport arteries. Moreover, far more kills occurred close to villages than in remote areas. This, combined with the lack of support for structural equation models that included latent terms for prey depletion driven by past overhunting, suggests that kill locations in this system tended to be driven by where hunters were currently foraging rather than by influences of historical harvest. These analyses are generalizable to a variety of ecosystems, species, and data types, providing a powerful way of enhancing maps and predictions of hunting effort across complex landscapes. Article impact statement: Locations of bushmeat hunter kill sites in Guyana seem driven by where hunters go currently rather than by historical influences of harvest. [ABSTRACT FROM AUTHOR]

Rain forests on Borneo support exceptional concentrations of endemic insect biodiversity, but many of these forest‐dependent species are threatened by land‐use change. Totally protected areas (TPAs) of forest are key for conserving biodiversity, and we examined the effectiveness of the current TPA network for conserving range‐restricted butterflies in Sabah (Malaysian Borneo). We found that mean diurnal temperature range and precipitation of the wettest quarter of the year were the most important predictors of butterfly distributions (N = 77 range‐restricted species), and that species richness increased with elevation and aboveground forest carbon. On average across all species, TPAs were effective at conserving ~43% of species' ranges, but encompassed only ~40% of areas with high species richness (i.e., containing at least 50% of our study species). The TPA network also included only 33%–40% of areas identified as high priority for conserving range‐restricted species, as determined by a systematic conservation prioritization analysis. Hence, the current TPA network is reasonably effective at conserving range‐restricted butterflies, although considerable areas of high species richness (6,565 km2) and high conservation priority (11,152–12,531 km2) are not currently protected. Sabah's remaining forests, and the range‐restricted species they support, are under continued threat from agricultural expansion and urban development, and our study highlights important areas of rain forest that require enhanced protection. Abstract in Malay is available with online material. [ABSTRACT FROM AUTHOR]

Copyright of Conservation Biology is the property of Wiley-Blackwell and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Periods of extreme food abundance, such as irregular masting events, can dramatically affect animal populations and communities, but the extent to which anthropogenic disturbances alter animal responses to mast events is not clear. In South‐East Asia, dipterocarp trees reproduce in mast fruiting events every 2–10 years in some of the largest masting events on the planet. These trees, however, are targeted for selective logging, reducing the intensity of fruit production and potentially affecting multiple trophic levels.Moreover, animal responses to resource pulse events have largely been studied in systems where the major mast consumers have been extirpated. We sought to evaluate the influence of human‐induced habitat disturbance on animal responses to masting in a system where key mast consumers remain extant.We used motion‐triggered camera traps to quantify terrestrial mammal and bird occurrences in Sabah, Malaysian Borneo, relative to variation in fruit biomass from 69 plant families during a major (2014) and minor (2015) masting event and a non‐mast year (2013), in both logged and unlogged forests.Bearded pigs (Sus barbatus) showed the clearest responses to masting and occurrence rates were highest in unlogged forest in the year following the major mast, suggesting that the pulse in fruit availability increased immigration or reproduction. We also detected local‐scale spatial tracking of dipterocarp fruits in bearded pigs in unlogged forest, while this was equivocal in other species. In contrast, pigs and other vertebrate taxa in our study showed limited response to spatial or temporal variation in fruit availability in logged forest.Our findings suggest that vertebrates, namely bearded pigs, may respond to masting via movement and increased reproduction, but that these responses may be attenuated by habitat disturbance. [ABSTRACT FROM AUTHOR]

Understanding the mechanisms driving declines in biodiversity with latitude requires assessing if there are ecological limits to the number of species that can coexist, and if these limits vary with latitude, both of which are long‐standing and currently debated questions. Here I show that diversification of North American mammals across the Cenozoic Era slowed as diversity increased. This damping of diversification rates indicates ecological limitation, which occurred even though diversity fluctuated through time and was almost never at an equilibrium 'saturation' point. The estimated environmental carrying capacity was correlated with global temperature positively at high latitudes and negatively at low latitudes. Geographical variation in how standing diversity affects diversification rates could help explain the latitudinal biodiversity gradient as well as changes in the strength of the gradient over time. [ABSTRACT FROM AUTHOR]

Abstract: Protected areas form the cornerstone of global efforts to conserve biodiversity. Most current methods for designing reserve networks focus on maximizing the representation of species, but with no assurance that those species will persist in the protected landscapes into the future. We present a new strategy for reserve design that combines metapopulation theory with spatial conservation prioritization to estimate conservation solutions that minimize extinction risk across numerous species simultaneously. Our framework optimizes the spatial configuration of reserves to maximize metapopulation persistence for an entire assemblage of species by accounting for both species representation and landscape connectivity. As a case study, we design a reserve network for 114 terrestrial mammal species in Indonesian New Guinea. Our approach builds on Marxan, the flagship representation‐based reserve design tool, improving estimated persistence (metapopulation capacity) by an average of 4.6‐fold across species, without increasing the socioeconomic cost. We suggest that enhancing species persistence, rather than protecting arbitrary proportions of species’ ranges, should be the ultimate objective of conservation planning. [ABSTRACT FROM AUTHOR]

Abstract: Past and ongoing vertebrate introductions threaten to rearrange ecological communities in the Indo‐Malay Archipelago, one of Earth's most biodiverse regions. But the consequences of these translocations are difficult to predict. We compared local abundance and distributions in four tropical mammal lineages that have crossed from Asia to Wallacea or New Guinea. The local abundance of macaques (Macaca spp.), which naturally crossed Wallace's Line, was higher in Sulawesi (east of the line; mean = 3.7 individuals per camera station, 95% CI = 2.2: 5.1) than in Borneo (west of the line; mean = 1.1, CI = 0.8: 1.4), but the local abundance of Malay civets (Viverra tangalunga), Rusa deer, and Sus pigs was similar in their native ranges and where they had been introduced by humans east of Wallace's Line. Proximity to rivers increased Malay Civet local abundance and decreased the local abundance of pigs in parts of their introduced ranges (Maluku and New Guinea, respectively), while having no effect on local abundance in their native ranges (Borneo) or other areas where they have been introduced (Sulawesi). That local abundance was higher east of Wallace's Line in just one of four mammal lineages is consistent with findings from plant invasions, where most species have similar abundance in their native and introduced ranges. However, species’ ecology may change as they enter new communities, for example, their patterns of abundance at local scales. This could make it difficult to predict community structure in the face of ongoing species introductions. [ABSTRACT FROM AUTHOR]

Abstract: We developed a new modeling framework to assess how the local abundance of one species influences the local abundance of a potential competitor while explicitly accounting for differential responses to environmental conditions. Our models also incorporate imperfect detection as well as abundance estimation error for both species. As a case study, we applied the model to four pairs of mammal species in Borneo, surveyed by extensive and spatially widespread camera trapping. We detected different responses to elevation gradients within civet, macaque, and muntjac deer species pairs. Muntjac and porcupine species varied in their response to terrain ruggedness, and the two muntjac responded different to river proximity. Bornean endemic species of civet and muntjac were more sensitive than their widespread counterparts to habitat disturbance (selective logging). Local abundance within several species pairs was positively correlated, but this is likely due to the species having similar responses to (unmodeled) environmental conditions or resources rather than representing facilitation. After accounting for environment and correcting for false absences in detection, negative correlations in local abundance appear rare in tropical mammals. Direct competition may be weak in these species, possibly because the ‘ghost of competition past’ or habitat filtering have already driven separation of the species in niche space. The analytical framework presented here could increase basic understanding of how ecological interactions shape patterns of abundance across the landscape for a range of taxa, and also provide a powerful tool for forecasting the impacts of global change. [ABSTRACT FROM AUTHOR]

Vertebrate granivores destroy plant seeds, but whether animal-induced seed mortality alters plant recruitment varies with habitat context, seed traits, and among granivore species. An incomplete understanding of seed predation makes it difficult to predict how widespread extirpations of vertebrate granivores in tropical forests might affect tree communities, especially in the face of habitat disturbance. Many tropical forests are simultaneously affected by animal loss as well as habitat disturbance, but the consequences of each for forest regeneration are often studied separately or additively, and usually on a single plant demographic stage. The combined impacts of these threats could affect plant recruitment in ways that are not apparent when studied in isolation. We used wire cages to exclude large (elephants), medium, (sambar deer, bearded pigs, muntjac deer), and small (porcupines, chevrotains) ground-dwelling mammalian granivores and herbivores in logged and unlogged forests in Malaysian Borneo. We assessed the interaction between habitat disturbance (selective logging) and experimental defaunation on seed survival, germination, and seedling establishment in five dominant dipterocarp tree species spanning a 21-fold gradient in seed size. Granivore-induced seed mortality was consistently higher in logged forest. Germination of unpredated seeds was reduced in logged forest and in the absence of small to large-bodied mammals. Experimental defaunation increased germination and reduced seed removal but had little effect on seed survival. Seedling recruitment however, was more likely where logging and animal loss occurred together. The interacting effects of logging and hunting could therefore, actually increase seedling establishment, suggesting that the loss of mammals in disturbed forest could have important consequences for forest regeneration and composition. [ABSTRACT FROM AUTHOR]

We examined the links between the science and policy of habitat corridors to better understand how corridors can be implemented effectively. As a case study, we focused on a suite of landscape-scale connectivity plans in tropical and subtropical Asia (Malaysia, Singapore, and Bhutan). The process of corridor designation may be more efficient if the scientific determination of optimal corridor locations and arrangement is synchronized in time with political buy-in and establishment of policies to create corridors. Land tenure and the intactness of existing habitat in the region are also important to consider because optimal connectivity strategies may be very different if there are few, versus many, political jurisdictions (including commercial and traditional land tenures) and intact versus degraded habitat between patches. Novel financing mechanisms for corridors include bed taxes, payments for ecosystem services, and strategic forest certifications. Gaps in knowledge of effective corridor design include an understanding of how corridors, particularly those managed by local communities, can be protected from degradation and unsustainable hunting. There is a critical need for quantitative, data-driven models that can be used to prioritize potential corridors or multicorridor networks based on their relative contributions to long-term metacommunity persistence. [ABSTRACT FROM AUTHOR]

Copyright of Conservation Biology is the property of Wiley-Blackwell and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Elucidating how dispersal and landscape connectivity influence metacommunity stability will shed light on natural processes structuring ecosystems and help prioritize conservation actions in an increasingly fragmented world. Much of the theoretical and mathematical development of the metacommunity concept has been based on simplified experimental systems or simulated data. We still have limited understanding of how variation in the habitat matrix and species-specific differences in dispersal ability contribute to metacommunity dynamics in heterogeneous landscapes. We model a metacommunity of rainforest mammals in Borneo, a tropical biodiversity hotspot, where protected areas are increasingly isolated by ongoing habitat disturbance and loss. We employ a combination of hierarchical models of local abundance, circuit-theory-based dispersal analysis, and metapopulation models. Our goal was to understand which landscape links were the most important to metapopulation persistence and metacommunity stability. Links were particularly important if they were short and connected two large patches. This was partly because only the very shortest links could be traversed by poorly dispersing species, including small herbivores such as chevrotains ( Tragulus spp.) and porcupines. Links that join large patches into a 'super-patch' may also promote island-mainland rather than Levins-type metapopulation dynamics for good dispersers, particularly large carnivores such as clouded leopards ( Neofelis diardi) and sun bears ( Helarctos malayanus), reducing metapopulation extinction risk and thereby enhancing metacommunity stability. Link importance to metacommunity stability was highly correlated between heterogeneous and homogeneous landscapes. But link importance to metapopulation capacity varied strongly across species, and the correlation between heterogeneous and homogeneous landscape matrix scenarios was low for poorly dispersing taxa. This suggests that the environmental conditions in the area between habitat patches, the landscape matrix, is important for assessing certain individual species but less so for understanding the stability of the entire metacommunity. [ABSTRACT FROM AUTHOR]

Although climate change and the expansion of agriculture are two of the primary threats to global biodiversity, they are usually considered independently. Here, I show that climate change and agricultural expansion interact synergistically in their impacts on mammals across mega-biodiverse Southeast Asia. Rising temperatures do not directly reduce niche availability for most species but do trigger a major altitudinal expansion in the cultivation zone for oil palm ( Elaeis guineensis), a cold-intolerant crop tree that is currently restricted to tropical lowlands. The resulting replacement of native forests would reduce mammal ranges by 47-67% by 2070, given a low- or high-carbon-emissions trajectory, respectively. This reduction is 3-4 times the magnitude of that predicted from land-use change without considering climatic effects. The synergistic interaction between climate change and land-use change greatly outweighs the impact on biodiversity of either factor alone or their additive combination. [ABSTRACT FROM AUTHOR]

Agricultural expansion is the largest threat to global biodiversity. In particular, the rapid spread of tree plantations is a primary driver of deforestation in hyperdiverse tropical regions. Plantations tend to support considerably lower biodiversity than native forest, but it remains unclear whether plantation traits affect their ability to sustain native wildlife populations, particularly for threatened taxa. If animal diversity varies across plantations with different characteristics, these traits could be manipulated to make plantations more "wildlife friendly." The degree to which plantations create edge effects that degrade habitat quality in adjacent forest also remains unclear, limiting our ability to predict wildlife persistence in mixed-use landscapes. We used systematic camera trapping to investigate mammal occurrence and diversity in oil palm plantations and adjacent forest in Sabah, Malaysian Borneo. Mammals within plantations were largely constrained to locations near native forest; the occurrence of most species and overall species richness declined abruptly with decreasing forest proximity from an estimated 14 species at the forest ecotone to ~1 species 2 km into the plantation. Neither tree height nor canopy cover within plantations strongly affected mammal diversity or occurrence, suggesting that manipulating tree spacing or planting cycles might not make plantations more wildlife friendly. Plantations did not appear to generate strong edge effects; mammal richness within forest remained high and consistent up to the plantation ecotone. Our results suggest that land-sparing strategies, as opposed to efforts to make plantations more wildlife-friendly, are required for regional wildlife conservation in biodiverse tropical ecosystems. [ABSTRACT FROM AUTHOR]

Humans influence tropical rainforest animals directly via exploitation and indirectly via habitat disturbance. Bushmeat hunting and logging occur extensively in tropical forests and have large effects on particular species. But how they alter animal diversity across landscape scales and whether their impacts are correlated across species remain less known. We used spatially widespread measurements of mammal occurrence across Malaysian Borneo and recently developed multispecies hierarchical models to assess the species richness of medium- to large-bodied terrestrial mammals while accounting for imperfect detection of all species. Hunting was associated with 31% lower species richness. Moreover, hunting remained high even where richness was very low, highlighting that hunting pressure persisted even in chronically overhunted areas. Newly logged sites had 11% lower species richness than unlogged sites, but sites logged >10 years previously had richness levels similar to those in old-growth forest. Hunting was a more serious long-term threat than logging for 91% of primate and ungulate species. Hunting and logging impacts across species were not correlated across taxa. Negative impacts of hunting were the greatest for common mammalian species, but commonness versus rarity was not related to species-specific impacts of logging. Direct human impacts appeared highly persistent and lead to defaunation of certain areas. These impacts were particularly severe for species of ecological importance as seed dispersers and herbivores. Indirect impacts were also strong but appeared to attenuate more rapidly than previously thought. The lack of correlation between direct and indirect impacts across species highlights that multifaceted conservation strategies may be needed for mammal conservation in tropical rainforests, Earth's most biodiverse ecosystems. Correlación y Persistencia de los Impactos de la Caza y la Tala sobre los Mamíferos de los Bosques Tropicales [ABSTRACT FROM AUTHOR]

Habitat corridors are important tools for maintaining connectivity in increasingly fragmented landscapes, but generally they have been considered in single-species approaches. Corridors intended to facilitate the movement of multiple species could increase persistence of entire communities, but at the likely cost of being less efficient for any given species than a corridor intended specifically for that species. There have been few tests of the trade-offs between single- and multispecies corridor approaches. We assessed single-species and multispecies habitat corridors for 5 threatened mammal species in tropical forests of Borneo. We generated maps of the cost of movement across the landscape for each species based on the species' local abundance as estimated through hierarchical modeling of camera-trap data with biophysical and anthropogenic covariates. Elevation influenced local abundance of banded civets ( Hemigalus derbyanus) and sun bears ( Helarctos malayanus). Increased road density was associated with lower local abundance of Sunda clouded leopards ( Neofelis diardi) and higher local abundance of sambar deer ( Rusa unicolor). Pig-tailed macaque ( Macaca nemestrina) local abundance was lower in recently logged areas. An all-species-combined connectivity scenario with least-cost paths and 1 km buffers generated total movement costs that were 27% and 23% higher for banded civets and clouded leopards, respectively, than the connectivity scenarios for those species individually. A carnivore multispecies connectivity scenario, however, increased movement cost by 2% for banded civets and clouded leopards. Likewise, an herbivore multispecies scenario provided more effective connectivity than the all-species-combined scenario for sambar and macaques. We suggest that multispecies habitat connectivity plans be tailored to groups of ecologically similar, disturbance-sensitive species to maximize their effectiveness. Evaluación de la Conectividad de Terrenos Multiespecie en una Comunidad Tropical de Mamíferos [ABSTRACT FROM AUTHOR]

In this article, the author of the article "Are wolves saving Yellowstone's aspen? A landscape-level test of a behaviorally mediated trophic cascade" comments on review of the article that was published in 2010 of the journal.

Ecological restoration typically focuses on promoting vegetation recovery in degraded habitat or reintroducing endangered animals to enhance their regional or global persistence. Here, we argue that attention should also be devoted to vertebrate reintroductions in overhunted but floristically intact tropical forests in order to prevent insidious regime shifts in these systems. Growing evidence suggests that tropical forests deprived of seed-dispersing animals exhibit replacement of fleshy fruiting trees by species with abiotic seed dispersal. Left unchecked, this process could eventually render the forest uninhabitable by frugivores through reduced density and diversity of their food plants. In tropical areas where hunting can be controlled, we contend that frugivore reintroduction, regulation of wild fruit harvest by humans, and outplanting of native fruiting trees should be deployed as management tools long before the systems are in need of traditional habitat restoration. [ABSTRACT FROM AUTHOR]

Summary 1. Matrix population models capture how variation in vital rates among life stages translates to population dynamics. Analyses of these models generally assume that populations have reached a stable stage distribution (SSD), where the proportion of individuals in each stage remains constant. However, when life stages respond differentially to environmental cues and perturbations, a population may be moved away from equilibrium. Given the multitude of stochastic processes acting in natural systems, populations may never be exactly at SSD. It is thus critical to understand how far away populations are from SSD and how distance from SSD influences near-term model projections. 2. We analysed published matrix models from 46 plant species spanning a range of life histories that reported both a current stage distribution and projection matrix. We examined the distance between observed and theoretical SSD and the associated consequences for near-term transient population dynamics for each species. 3. In the majority of studies, populations were near their expected SSD, with 80% falling within one unit of a projection distance (α0) of zero. This distribution was skewed towards positive values of α0, indicating that the majority of populations had individuals concentrated into stages with high reproductive values. 4. Half of the populations in our survey had projection distances such that transient projections of population size and growth rate were within 10% of asymptotic projections at 5 years. However, in populations where projection distance was > 2, deviations from SSD caused important (more than twofold) differences. 5. We also found that larger deviations from SSD were positively correlated with generation time and matrix size. 6. Synthesis. When some life stages within a plant population are more strongly affected by disturbances or stresses than others, the results of our literature survey suggest that equilibrium projections will tend to underestimate projections that account for the current stage distribution. Measuring the current stage distribution can help determine whether asymptotic measures of matrix model analyses are reliable, and is a crucial step to take when precise population metrics are necessary for guiding conservation and management. [ABSTRACT FROM AUTHOR]

To understand the changing role of funding sources in shaping conservation science in the United States, we analyzed acknowledgments from published studies, trends in research funding, and survey responses from conservation scientists. Although the U.S. federal government was the most frequently acknowledged source of support overall, U.S. foundations and NGOs were the predominant sources for tropical and socioeconomic research. Acknowledgments of foundation support for conservation research increased over the last two decades, while recognition of federal funds declined. Concordant trends in funding and acknowledgments indicated a changing landscape for conservation science, in which federal support has not kept pace with the growth in conservation research efforts or needs. Survey responses from conservation scientists about their funding sources were consistent with acknowledgment data, and most (64%) indicated that shifts in funding sources and amounts affected the type of research they conduct. Ongoing changes in the funding landscape shape the direction of conservation research and may make conservation science more vulnerable to economic recessions. [ABSTRACT FROM AUTHOR]

Behaviorally mediated trophic cascades (BMTCs) occur when the fear of predation among herbivores enhances plant productivity. Based primarily on systems involving small-bodied predators, BMTCs have been proposed as both strong and ubiquitous in natural ecosystems. Recently, however, synthetic work has suggested that the existence of BMTCs may be mediated by predator hunting mode, whereby passive (sit-and-wait) predators have much stronger effects than active (coursing) predators. One BMTC that has been proposed for a wide-ranging active predator system involves the reintroduction of wolves (Canis lupus) to Yellowstone National Park, USA, which is thought to be leading to a recovery of trembling aspen (Populus tremuloides) by causing elk (Cervus elaphus) to avoid foraging in risky areas. Although this BMTC has been generally accepted and highly popularized, it has never been adequately tested. We assessed whether wolves influence aspen by obtaining detailed demographic data on aspen stands using tree rings and by monitoring browsing levels in experimental elk exciosures arrayed across a gradient of predation risk for three years. Our study demonstrates that the historical failure of aspen to regenerate varied widely among stands (last recruitment year ranged from 1892 to 1956), and our data do not indicate an abrupt cessation of recruitment. This pattern of recruitment failure appears more consistent with a gradual increase in elk numbers rather than a rapid behavioral shift in elk foraging following wolf extirpation. In addition, our estimates of relative survivorship of young browsable aspen indicate that aspen are not currently recovering in Yellowstone, even in the presence of a large wolf population. Finally, in an experimental test of the BMTC hypothesis we found that the impacts of elk browsing on aspen demography are not diminished in sites where elk are at higher risk of predation by wolves. These findings suggest the need to further evaluate how trophic cascades are mediated by predator-prey life history and ecological context. [ABSTRACT FROM AUTHOR]

Understanding the population-level impacts of climate change is critical for effectively managing ecosystems. Predators are important components of many systems because they provide top−down control of community structure. Ecological theory suggests that these species could be particularly susceptible to climate change because they generally occur at low densities and have resource-limited populations. Yet, our understanding of climate-change impacts on predators is hindered by the difficulty in assessing complex, nonlinear dynamics over the large spatial scales necessary to depict a species’ general response to abiotic forcing. Here we use fur-return data to characterize population dynamics of a snow-adapted carnivore, the wolverine, across most of its North American range. Using novel modeling techniques, we simultaneously measured the impact of winter snowpack on wolverine dynamics across critical thresholds in snowpack depth and two domains of population growth. Winter snowpack declined from 1970 to 2004 in nearly the entire region studied, concordant with increases in Northern Hemisphere temperature anomalies. Fur returns have declined in many areas; our models show that snowpack has strong, nonlinear effects on wolverine population dynamics. Importantly, wolverine harvests dropped the fastest in areas where snowpack declined most rapidly and also where snowpack had the greatest effect on population dynamics. Moreover, declining snow cover appears to drive trends in wolverine population synchrony, with important implications for overall persistence. These results illustrate the vulnerability and complex responses of predator populations to climate change. We also suggest that declining snowpack may be an important and hitherto little-analyzed mechanism through which climate change alters high-latitude ecosystems. [ABSTRACT FROM AUTHOR]

The selection of bedding sites is important for the ecology of ruminants, but has mainly been described for temperate species. Here we assessed the bed site selection of two Southeast Asian tropical deer, red muntjac and sambar, in Khao Yai National Park, Thailand. We surveyed transects weekly for 10 weeks each in 2003 and 2004 to locate bed sites, and compared the slope, aspect, and forest canopy cover of bed site locations between the two species and with available habitat. As with most temperate deer, muntjac and sambar both avoided sites with low levels of cover for their bed site locations; this could be for concealment or thermoregulation. Sambar also selected flatter sites than would be expected by the availability of topographic slopes; this could be to reduce the energy associated with getting to and from bed sites, or to increase long-range visibility from sites. Muntjac and sambar differed in their choice of aspects for bed sites; muntjac disproportionately chose west-facing areas, while sambar chose east-facing locations. This could represent a strategy by which one species avoids the other, or else differential resource requirements between the two species. [ABSTRACT FROM AUTHOR]

The article presents a study which examines the effects of bushmeat poaching in the seed dispersal and population growth rate of a mammal-dispersed tree. It cites that overharvest threatens myriad tropical vertebrates and several tropical birds and mammals disperse seeds. The study determines how variation in hunting pressure influence the relative abundance of gibbons, muntjac deer, and sambar deer which are the sole disperses of seeds of the canopy tree Choerespondias axillaris in the four national parks with seasonal forest in Northern Thailand. The study revealed that the extinction of C. axillaris is a possibility and the recent and ongoing extirpations of vertebrates could be the contributing factor for such extinction.

Many plants interact with groups of mutualist pollinators and seed dispersers. A key issue for both basic ecology and conservation is whether the different species within these guilds of mutualist animals are functionally equivalent. Comparing the relative effects of sympatric mutualists is important for understanding the evolution of multispecies mutualisms and for predicting mutualism stability in the face of anthropogenic change. However, empirical comparisons of the population-level impacts of mutualist animals on their host plant are rare, particularly for seed dispersal mutualisms in species-rich ecosystems. We compared the influence of three seed-dispersing tropical mammals, lar gibbons (Hylobates lar), sambar deer (Rusa unicolor), and red muntjac deer (Muntiacus muntjak), on the demography of a shared host tree in Thailand, Choerospondias axillaris (Anacardiaceae). Sambar and muntjac dispersed far more C. axillaris seeds than did gibbons. While sambar deposited many seeds under female tree canopies, muntjac were the only disperser to move seeds to open microhabitats, where C. axillaris seed germination, seedling survival, and initial growth are enhanced. Using stage-based population models, we assessed how disperser-specific seed dispersal, variation in the frequency of canopy gap formation, and their interaction influenced the potential population growth of C. axillaris. Large differences in dispersal quantity and small differences in dispersal quality among sambar and gibbons resulted in similar and negligible impacts on the tree's population dynamics. Muntjac, by taking some of the seeds to open microhabitats, are projected to have a greater positive impact on C. axillaris demography than either sambar or gibbons. Model comparisons of population-level species impacts may allow us to predict which ecological interactions are at risk from loss of critical species. [ABSTRACT FROM AUTHOR]

Indices or density estimators derived from counts of scat can be used as indirect measures of animal population density. An important issue in these studies is that scat decay rates vary across habitats and seasons. This is an often overlooked source of bias when using scat-based indices to make comparisons of relative abundance among sites or over time. I propose a simple method by which experimentally determined scat-persistence rates can be used as a correction factor in such indices. This measured persistence rate also serves as an important parameter in models that convert scat count data into population estimators. I test this method in a relative abundance survey of sambar deer (Cervus unicolor) for 6 sites across 2 national parks in northern Thailand. Using the correction factor changed the qualitative predictions of the abundance survey by altering the rank of the sites ordered by estimated sambar density. The ratio of corrected:uncorrected index values, which would stay constant across sites if there was no habitat-based variability in scat-persistence rates, changed by a factor of 2.7 when measured across sites and by 1.6 when measured across parks. This suggests that the application of persistence-rate correction factors could reduce the bias of scat-based index or estimator surveys by specifically accounting for decay rate variability. [ABSTRACT FROM AUTHOR]

The expansion of shrubs and trees across high‐latitude ecosystems is one of the most dramatic ecological manifestations of climate change. Most of the work quantifying these changes has been done in small areas and over relatively recent time scales. These land‐cover transitions are highly spatially variable, and we have limited understanding of the factors underlying this variation. We use repeat photography to generate a data set of land‐cover changes in Denali National Park and Preserve, Alaska, stretching back a century and spanning a range of edaphic, topographic, and climatic conditions. Most land‐cover classes were quite stable, with low probabilities of transitioning to other land‐cover types. The advance of woody vegetation into low‐stature tundra, and the spread of conifer trees into shrub‐dominated areas, were both more likely at low elevations and in areas without permafrost. Permafrost also reduced the likelihood of herbaceous vegetation transitioning to woody cover. Exceptions to the general trend of relative stability included nearly all (96%) of the broadleaf forest–dominated areas being invaded by conifers, an expected successional trajectory, and many open gravel river bars (17.8%) transitioning to thick shrubs. These floodplain areas were distinctly not at equilibrium, as only 0.1% of shrub‐dominated areas converted to gravel. Warming temperatures in coming decades and concomitant declines in the extent of permafrost are predicted to enhance the spread of woody vegetation in Denali further, but only by ~3%. Land‐cover transitions, notably the rapid advance of trees and shrubs observed in other studies, could be less likely and more spatially heterogeneous here than in other high‐latitude systems. [ABSTRACT FROM AUTHOR]