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At high elevation or latitude, trees reach low-temperature range limits. In attempting an explanation, the range limits of individual tree species (set by freezing tolerance) and the general limit of the life-form tree (set by thermal growth constraints) need to be distinguished. The general cold edge of the fundamental niche of trees is termed the treeline, by definition, the lower edge of the alpine belt, a most important bioclimatological reference line. Trees can be absent from the treeline due to disturbances or biotic interactions. The actual local edge of tree distribution, the delineation of the realized niche, is driven by stochastic effects. Therefore, treeline theory and hypothesis testing is inevitably tied to the fundamental niche concept.

Coccolithophores are potentially affected by ongoing ocean acidification, where rising CO2 lowers seawater pH and calcite saturation state (Ωcal). Southern Patagonian fjords and channels provide natural laboratories for studying these issues due to high variability in physical and chemical conditions. We surveyed coccolithophore assemblages in Patagonian fjords during late spring 2015 and early spring 2017. Surface Ωcal exhibited large variations driven mostly by freshwater inputs. High-Ωcal conditions (max. 3.6) occurred in the Archipelago Madre de Dios. Ωcal ranged from 2.0–2.6 in the western Strait of Magellan and 1.5–2.2 in the inner channel and was subsaturating (0.5) in Skyring Sound. Emiliania huxleyi was the only coccolithophore widely distributed in Patagonian fjords (> 96 % of total coccolithophores), only disappearing in the Skyring Sound, a semi-closed mesohaline system. Correspondence analysis associated higher E. huxleyi biomasses with lower diatom biomasses. The highest E. huxleyi abundances in Patagonia were in the lower range of those reported in Norwegian fjords. Predominant morphotypes were distinct from those previously documented in nearby oceans but similar to those of Norwegian fjords. Moderately calcified forms of E. huxleyi A morphotype were uniformly distributed throughout Patagonia fjords. The exceptional R/hyper-calcified coccoliths, associated with low Ωcal values in Chilean and Peruvian coastal upwellings, were a minor component associated with high Ωcal levels in Patagonia. Outlying mean index (OMI) niche analysis suggested that pH and Ωcal conditions explained most variation in the realized niches of E. huxleyi morphotypes. The moderately calcified A morphotype exhibited the widest niche breadth (generalist), while the R/hyper-calcified morphotype exhibited a more restricted realized niche (specialist). Nevertheless, when considering an expanded sampling domain, including nearby southeast Pacific coastal and offshore waters, even the R/hyper-calcified morphotype exhibited a higher niche breadth than other closely phylogenetically related coccolithophore species. The occurrence of E. huxleyi in naturally low pH–Ωcal environments indicates that its ecological response is plastic and capable of adaptation.

Shifts in the realized niches of exotic species may play an important role in their invasion. Galinsoga quadriradiata has invaded China widely and occupied many climate zones that are different from its native range. We addressed the climatic niche shift of G. quadriradiata and evaluated how this could contribute to its invasion in China. We used the Maxent model to predict the potential distribution of G. quadriradiata using its native and invaded range occurrences and climatic variables. Principal component analysis was conducted to measure climatic niche shifts of G. quadriradiata during its invasion in China. The models revealed only 32.7% niche overlap between the native and invasive populations. The niche similarity of the two populations was significantly low (Schoener’s D = 0.093, P < 0.005), suggesting the occurrence of a niche shift. The envelop and center of the realized climatic niche in China has shifted to lower temperature and less precipitation compared to that in its native range. The majority of invaded areas in southern China are in the stabilizing zone, whereas the colonization and adaptation zones are predicted to be at the leading edge of G. quadriradiata invasion in northern China. This suggests that the regional distribution of G. quadriradiata may be in a quasi-equilibrium state, and that the species continues to invade environmentally suitable areas. Alterations in G. quadriradiata’s niche would help to explain why this species is so invasive in China.

The studies of climatic‐niche shifts over evolutionary time accompanied by key morphological innovations have attracted the interest of many researchers recently. We applied ecological niche models (ENMs), ordination method (environment principal component analyses; PCA‐env), combined phylogenetic comparative methods (PCMs), and phylogenetic generalized least squares (PGLS) regression methods to analyze the realized niche dynamics and correspondingly key morphological innovations across clades within Scutiger boulengeri throughout their distributions in Qinghai–Tibet Plateau (QTP) margins of China. Our results show there are six clades in S. boulengeri and obvious niche divergences caused by niche expansion in three clades. Moreover, in our system, niche expansion is more popular than niche unfilling into novel environmental conditions. Annual mean temperature, annual precipitation, and precipitation of driest month may contribute to such a shift. In addition, we identified several key climatic factors and morphological traits that tend to be associated with niche expansion in S. boulengeri clades correspondingly. We found phenotypic plasticity [i.e., length of lower arm and hand (LAHL), hind‐limb length (HLL), and foot length (FL)] and evolutionary changes [i.e., snout–vent length (SVL)] may together contribute to niche expansion toward adapting novel niche, which provides us a potential pattern of how a colonizing toad might seed a novel habitat to begin the process of speciation and finally adaptive radiation. For these reasons, persistent phylogeographic divisions and accompanying divergences in niche occupancy and morphological adaption suggest that for future studies, distinct genetic structure and morphological changes corresponding to each genetic clade should be included in modeling niche evolution dynamics, but not just constructed at the species level., Persistent phylogeographic divisions and accompanying divergences in niche occupancy and morphological adaption suggest that for future studies, distinct genetic structure and morphological changes corresponding to each genetic clade should be included in modeling niche evolution dynamics, but not just constructed at the species

Aim To investigate whether the frequently advocated climate‐matching species distribution modeling approach could predict the well‐characterized colonization of Florida by the Madagascar giant day gecko Phelsuma grandis. Location Madagascar and Florida, USA. Methods To determine the climatic conditions associated with the native range of P. grandis, we used native‐range presence‐only records and Bioclim climatic data to build a Maxent species distribution model and projected the climatic thresholds of the native range onto Florida. We then built an analogous model using Florida presence‐only data and projected it onto Madagascar. We constructed a third model using native‐range presences for both P. grandis and the closely related parapatric species P. kochi. Results Despite performing well within the native range, our Madagascar Bioclim model failed to identify suitable climatic habitat currently occupied by P. grandis in Florida. The model constructed using Florida presences also failed to reflect the distribution in Madagascar by overpredicting distribution, especially in western areas occupied by P. kochi. The model built using the combined P. kochi/P. grandis dataset modestly improved the prediction of the range of P. grandis in Florida, thereby implying competitive exclusion of P. grandis by P. kochi from habitat within the former's fundamental niche. These findings thus suggest ecological release of P. grandis in Florida. However, because ecological release cannot fully explain the divergent occupied niches of P. grandis in Madagascar versus Florida, our findings also demonstrate some degree of in situ adaptation in Florida. Main conclusions Our models suggest that the discrepancy between the predicted and observed range of P. grandis in Florida is attributable to either in situ adaptation by P. grandis within Florida, or a combination of such in situ adaptation and competition with P. kochi in Madagascar. Our study demonstrates that climate‐matching species distribution models can severely underpredict the establishment risk posed by non‐native herpetofauna., Climate‐matching species distribution models (SDMs) are frequently used to predict biotic invasions. Our manuscript details how both release from native‐range competitors and in situ adaptation within the non‐native range have enabled the day gecko Phelsuma grandis to flourish in Florida under bioclimatic conditions classified as highly unsuitable by an otherwise‐well‐performing climate‐matching SDM. By identifying the large discrepancy between the predicted and observed range of P. grandis in Florida, our study highlights the shortcomings of climate‐matching SDMs as conservation management tools, while also providing valuable empirical evidence of the ecological and evolutionary processes underpinning this discrepancy.

Background Two coexisting species with similar ecological requirements avoid or reduce competition by changing the extent of their use of a given resource. Numerous coexistence mechanisms have been proposed, but species interactions can also be aggressive; thus, generally a subordinate species modifies its realized niche to limit the probability of direct encounters with the dominant species. We studied niche partitioning between two sympatric wild canids in north-eastern Italy: the golden jackal and the red fox, which, based on competition theories, have a high potential for competition. We considered four main niche dimensions: space, habitat, time, and diet. Results We investigated three study areas monitoring target species populations from March 2017 to November 2018 using non-invasive monitoring techniques. Red fox presence was ascertained in every study area, while golden jackal presence was not ascertained in one study area, where we collected data regarding wolf presence. Considering the two target species, we observed partial diet partitioning based on prey size, with the golden jackal mainly feeding on wild ungulates and the red fox mainly feeding on small mammals. The two canids had an extensive temporal overlap along the diel cycle, having both predominant crepuscular and nocturnal activity patterns, but marked spatial partitioning and differential use of habitats. The golden jackal proved to be specialist concerning the habitat dimension, while the red fox resulted completely generalist: the former selected less human-modified habitats and avoided intensively cultivated lands, while the latter was present in all habitats, including intensively cultivated lands. Conclusions The observed partitioning might be due partially to some ecological adaptations (e.g. specialist vs. generalist use of resources) and specific behaviours (e.g. cooperative vs. solitary hunting) and partially to the avoidance response of the red fox aimed at reducing the probability of direct encounters with the golden jackal.

Predicting the impact of climate change on species distribution at different spatial and temporal scales has emerged as one of the important areas of research in invasion ecology and conservation biology. We used MaxEnt (Maximum Entropy Algorithm) to predict the distribution of a highly invasive species, namely Parthenium hysterophorus L. under four Representative Concentration Pathway scenarios (RCPs 2.6, 4.5, 6.0 and 8.5) in 2050 and 2070 at global (world), regional (India) and local (Jammu & Kashmir State) spatial scales. Model predictions indicated differences in the extent of expansion in the distribution of this species under different climate change scenarios with marginal increase in moderately suitable area at the global scale but mostly a declining trend was noticed in its suitable and highly suitable area in future. More or less similar trend was predicted for India where increase in moderately suitable area was evident but decline in suitable and highly suitable areas was observed. In respect of Jammu & Kashmir, moderately suitable as well suitable area showed increase mostly under RCP scenarios of 6.0 and 8.5 in 2050 as well as 2070. Further analysis revealed that current centroid of P. hysterophorus is in south of Jammu and Kashmir and is predicted to shift by an average of 20.48 km in the north-west direction by 2050 and by 36.83 km by 2070. The future suitable area is likely to be around Hirapora Wildlife sanctuary in Kashmir. Pairwise comparison of the niche overlap and dynamics of P. hysterophorus between the native Americas and each of the regions (Africa, Asia, Australia and Oceania) where the species is introduced using Schoener’s D revealed variations in the niche overlap which was high between native Americas and Australia (0.70) and Africa (0.69), moderate between Americas and Asia (0.59) and low between Americas and Oceania (0.24). Exclusion of 25% of rare climatic conditions did not have any effect on the niche overlap index (D). Niche similarity test was not significant for any of the pairwise comparisons of native Americas and the continents in which the species is non-native indicating that the native niche is more similar to the exotic niche than any randomly sampled niche from the exotic range. But the niche equivalency tests showed that the environmental realized niche of P. hysterophorus in its invaded range was not totally equivalent to that in the native range indicating niche differentiation. The niche dynamic indices based on analogous and the entire climatic space in the native and introduced regions revealed a very high niche stability. A very limited niche expansion was noticed only in Asia and niche unfilling was evident in Oceania. Like niche overlap index (D), niche expansion and niche stability were not affected by the exclusion of 25% of rare climatic conditions but marginal change was noticed in niche unfilling in the Oceania. The above predictions have implications for formulation of policies at local, regional and global level for the management of this invasive species.

Vespa mandarinia Smith is a species with native distribution in Asia and with the potential distribution of invasion in the Americas. We use ecological niche models to be able to predict their potential distribution in Asia and their projection in the Americas using KUENM in R in climate change scenarios. The ecological niche of V. mandarinia is potentially distributed in Asia and is expected with invasion potential in the east coast of USA, part of the Mexico, Central America, and South America, while for 2050 it is projected with dispersion in North and Central of USA and rest of the Americas. The realized niche expanded in the Americas. Ecological niche modeling helps us infer the distribution of this species in Asia and its possible establishment of invasion in the USA, Mexico, Central America, and South America.

Seagrass restoration can help reverse global meadow loss and restore ecosystem services, including habitat provision for commercial fish and shellfish, carbon sequestration, and improved water quality. However, restoration projects are generally expensive, and site selection remains a challenge due to uncertainty about how environmental variables affect the survival and spread of seedlings. Long-term Zostera marina (eelgrass) success/failure and expansion data from the Virginia Coast Reserve can be used to determine whether the factors that control seedling survival also explain the regional distribution of seagrass meadows. We tracked plant survival and failure within restoration plots and at natural recruitment sites from 2001 to 2015 and used machine learning methods to identify the relative importance of multiple environmental predictors, including water residence time, fetch distance, water temperature, depth, and sediment grain size. Low water residence time was the best predictor of survival, but short fetch length best explained the natural recruit distribution, consistent with hydrodynamic control of seed dispersal. Restoration plot data suggests that the eelgrass fundamental niche covers > 100 km2 within this system, triple both the current extent and the realized niche predicted by the observed natural spread. Our results corroborate historical records that eelgrass was formerly widespread in areas where it has not spread naturally, likely due to insufficient seed delivery. Additional seeding in these areas would, therefore, increase total seagrass coverage and accelerate recovery. Mapping the total habitable area can help managers maximize the extent of seagrass and other bottom uses, including shellfish aquaculture.

The realized niche of the community, which is part of the association Astragalo borysthenici-Ephedsretum Korzh. et Klyukin 1990 (union Verbascion pinnatifidi Korzh. et Klukin 1990, order Festucetalia vaginatae Soo 1957, class Festucetea vaginatae Soo 1968 em Vicherek 1972) described on a leaning dune, is discussed. Its composition is dominated by polycarpic grasses, represented by ephemerals and ephemeroids with a semi-rosette type of vegetation and a deep taproot system. An attempt has been made to predict the survival of the species found in Agropyron dasyanthum Ledeb., known as the endemic of the Lower Dnieper sands. To assess the ecological structure of the realized niche of the phytocenosis and the correspondence to it of the potential niche of fluffy flowering wheatgrass, an original program for calculating the packing density of community species on the gradients of factor-conditions and factor-resources was used: acidity of the substrate, salt regime (anionic composition), carbonate content, nitrogen content, granulometric (mechanical) composition (porosity) of the substrate). The result of the analysis was an unambiguous conclusion that Agropyron dasyanthum Ledeb. in the new conditions of the shell-detritus substrate, it ideally fit into the conditions of the climatope and, more or less, into the structure of the edaphotope. The real threat to the community is theanthropogenic impact and loss of productivity in the Sea of Azov.

Ecological disturbances are recognized as a crucial factor influencing the attributes of ecological communities. Depending on the specific adaptation or life cycle, plant species show different responses to disturbances of different magnitudes. Herben et al. (Journal of Vegetation Science, 27, 628–636) proposed six disturbance indicator values (DIVs) that describe the niches of Central‐European plant species along gradients of disturbance frequency and severity. Here, we ask if the DIVs can be used in community ecology for bioindication of disturbance regime? We used a dataset of riparian forests sampled within mountain catchments (the Sudetes, SW Poland). As the regime of disturbance is driven by changes in floods from the spring toward the mouth, we calculated the position of every plot along longitudinal (upstream–downstream) gradient and used it as a proxy for the disturbance severity and frequency. We then calculated the community‐weighted means (CWMs) for each of the six indices for each plot and analyzed whether these indices reflected the position of the plots along the rivers. We expected an increase in the severity indices and a decrease in the frequency indices downstream along the rivers. Moreover, we analyzed relationships between disturbance indices and species optima along longitudinal gradient. Surprisingly, means for all analyzed indices increased along the rivers. Severity indices showed the strongest association with the longitudinal gradient. The disturbance severity index for herbs was the only index that differed significantly among species with different responses along longitudinal gradient. On these results, we identified a strong correlation between the severity and frequency indices as the main problem. We conclude that the DIVs have considerable applicative potential; however, the determination of ecological niches separately for disturbance severity and frequency is difficult because different components interact to shape the realized niche of each species. All analyzed indices encompass different attributes of the disturbance regime including both severity and frequency., We tested disturbance indicator values (DIVs) for its potential use in community ecology for bioindication of disturbance regime. The DIVs have considerable applicative potential; however, the determination of ecological niches separately for disturbance severity and frequency is difficult because different components interact to shape the realized niche of each species. All analyzed indices encompass different attributes of the disturbance regime including both severity and frequency.

Aim: The Tawny Coster Acraea terpsicore is a highly mobile butterfly that has recently expanded its spatial distribution from South Asia to South-East Asia and Australia. Here, we determine if the realized climatic niche has changed during the expansion and analyse the geographic pattern of spread in Australia.Location: Asia and Australia.Methods: We collated occurrence records, divided the geographic range into three spatio-temporal phases (pre-expansion, early-expansion and late-expansion) and then developed ecological niche models for each phase. To determine whether the realized niche has changed during the range expansion, we performed a principal component analyses and niche overlap analysis. Finally, we calculated the annual rate of range expansion to estimate the speed and pattern of geographic spread.Results: The climatic niche of A. terpsicore differs only slightly in the pre-expansion and late-expansion ranges and was most distinct in the early-expansion range. This species range expanded in Australia at an average rate of similar to 135 km/year (range: 34-359 km/year). Female-biased migration occurred in north-eastern Queensland at the leading edge of the range, the first documentation of this phenomenon in butterflies.Main Conclusions: Acraea terpsicore represents one of the fastest documented geographic range expansions of any species, highlighting how rapidly butterflies can colonize new areas, even where environmental conditions are substantially different to those in their original distribution. However, we found little evidence of climatic niche shift, and only a minor niche shift is apparent in the early-expansion and late-expansion ranges. It remains unclear what triggered the sudden expansion, but it has been hypothesized that tropical deforestation provided conditions that initiated local range expansion, and further work on the possible mechanisms involved is required.

The issue of the presence of a regenerative niche Malva alcea, recently discovered on the Ai-Petrinskaya Yila, is being discussed. This species is typical polycarpic grass, rooted, hemicryptophytes with summer-green vegetation type, entomogamous, barohor with generative propagation. The range of Malva alcea covers almost the whole of Europe, includingGreat Britain; it is also found inNorth America. To obtain an ambiguous answer, we used the original program for calculating the packing density of community species on gradients of factor conditions and resource factors: (illumination-shading, thermal mode, ombro mode, cryo mode, continentality, moistening, variability of moisture, substrate acidity, salt regime (anionic composition), carbonate content, nitrogen content, granulometric (mechanical) composition (porosity) of the substrate). Most often, the species can be found in the syntaxons included in the class - Onopordetea acanthii subsp. acanthii Braun-Blanquet 1964 em. Julve 1993, order - Onopordetalia acanthii subsp. acanthii Braun-Blanquet & Tüxen 1943 em. Görs 1966, union - Onopordion acanthii subsp. acanthii Braun-Blanquet 1936, which summarize the thermophilic ruderal communities of tall weed species. Based on the analysis results, it can be stated that the introduced species successfully occupied its ecological niche due to the successful differentiation of its fundamental niche into the realized niche of the existing plant community, as well as due to the availability of free resources in the ecotope, as evidenced by the negative value of the excess coefficient of the packing density curve.

Eavesdropping on community members has immediate and clear benefits. However, little is known regarding its importance for the organization of cross-taxa community structure. Furthermore, the possibility that eavesdropping could allow species to coexist with a predator and access risky foraging habitat, thereby expanding their realized niche, has been little considered. Kalahari tree skinks (Trachylepis spilogaster) associate with sociable weaver (Philetairus socius) colonies as do African pygmy falcons (Polihierax semitorquatus), a predator of skinks and weavers. We undertook observational and experimental tests to determine if skinks eavesdrop on sociable weavers to mitigate any increase in predation threat that associating with weaver colonies may bring. Observations reveal that skinks use information from weavers to determine when predators are nearby; skinks were more active, more likely to forage in riskier habitats, and initiated flight from predators earlier in the presence of weavers compared with when weavers were absent. Playback of weaver alarm calls caused skinks to increase vigilance and flee, confirming that skinks eavesdrop on weavers. Furthermore, skinks at sociable weaver colonies were more likely to flee than skinks at noncolony trees, suggesting that learning is mechanistically important for eavesdropping behavior. Overall, it appears that eavesdropping allows skinks at colony trees to gain an early warning signal of potential predators, expand their realized niche, and join communities, whose predators may otherwise exclude them.

Ecological niche models (ENMs) are widely used tools for predicting species geographic distribution as a function of environmental variables. The inclusion of biotic factors in the predictor suite can significantly increase the predictive power of such models, leading to a model closer to the realized niche for the species under investigation. In this study, we provide evidence of niche overlap between gray woolly monkeys (Lagothrix cana) and black-faced black spider monkeys (Ateles chamek) based on locality and ecological data covering their complete geographic range in the Amazon forests of Brazil, Peru and Bolivia. We also estimate the potential distribution of L. cana using environmental predictors, and the distribution of A. chamek as a biotic factor. Finally, we quantified current and future habitat loss and areas under legal protection. We found that only 39% of the L. cana area of occupancy is under legal protection and that the species could potentially lose up to 58% of habitat in the next 30 years. We also show that the use of a closely-related species that has a more robust dataset can improve ENMs of poorly studied, rare and/or cryptic species. The framework developed here can be applied to a wide range of sympatric species if they share similar ecological requirements. Since our focal species are the most frugivorous primates in our study region and especially vulnerable to habitat loss, the identification of highly suitable areas for both taxa can help to protect other forest-dwelling species, reducing the rate of overall biodiversity loss.

I describe my unlikely path into marine science from a childhood in the Arizona desert and Oregon woods. Without realizing it, I developed a sense of place in nature and the value of open interdisciplinary communication among diverse scientists. My undergraduate education emphasized physiological adaptations to the environment or what might now be considered the “fundamental niche”, and my graduate thinking was inspired by a population/community based evolutionary understanding of how strong interactions define a “realized niche”. I have attempted to define strong interactions in three different ecosystems. This difficult problem is confounded by the loss of natural systems resulting from human impacts. I discuss my frustrations with eroding conservation efforts in a society that is rapidly devaluing nature and consider how we might recover our most fundamental values. I conclude that there is an urgent need to improve field-based teaching of undergraduate non-majors about nature and to be much more effective in our interactions with the general public. If we hope to have our legacy include a liveable world with natural places, we urgently need to act unilaterally to shift some of our values and reward systems towards the challenge of educating the undergraduates and especially the general public.

International audience; We studied the realized niche of two distant allopatric wool-carder bee populations (bee-plant interaction and reproductive biology in weather variability). In one population, we analyzed the direct and indirect effects of weather on bee-resource interactions. The two populations shared several niche characteristics but showed some differences. Anthidium vigintipunctatum is a specialist species, with plasticity to extend the individual niche pushed by resources availability and weather variability. In both regions, the bee’s response to weather condition was similar (nesting rates and the reproductive success). Causal analysis indicated climate directly determines bee’s reproductive success, and indirect resource availability effects are subtle. The immediate response to environmental conditions warms about A. vigintipunctatum sensitivity to expected changes in the regional climate which could be a negative pressure on bees’ survival.

Wet meadows are a common focus of wetland restoration efforts, and the species within them often exist within a restricted range of water levels. Unfortunately, many restored wetlands have higher water levels and more open water than naturally occurring reference wetlands, and many are invaded and dominated by species of Typha. Most studies evaluating the optimal water level for plant species use observational methods, yet experimental methods are required to understand the breadth of a species’ niche. We used experimental transplants of Carex pellita, a common wet meadow sedge used in restoration in the interior of the USA, and Typha latifolia, a species of cattail which invades many restored wetlands, to test whether higher water levels in a restored wetland were prohibitive to the target sedge species. Physiological and growth measurements were collected on both species. We found that C. pellita grew as well or better when transplanted into the ponded water levels, while T. latifolia had reduced growth when transplanted into the relatively drier meadow conditions. Interestingly, C. pellita was able to adjust its Turgor Loss Point in response to changing water levels. Only recently the assumption of a constant Turgor Loss Point for each species has been questioned. Our results provide evidence that wet meadow species have a broader hydrologic niche than previously thought, and their ability to make physiological adjustments in response to changing water levels may allow them to thrive in areas with widely varying water levels.

Using species ranges, in particular those derived from species distribution models (SDM), to obtain characteristics of the species’ niche such as temperature tolerances is tempting. Over the past decade the literature has seen the increase in the use of SDMs based on locality data and spatially explicit datasets (climate, vegetation etc.). Furthermore, several studies have explored climatic niche evolution and niche conservatism using temperature and precipitation extracted from the resulting models in a phylogenetic context. However, species´ fundamental niches (set of abiotic conditions in which a species can live) are often incompletely characterized in SDMs, reconstructed mainly based on spotty locality data (about species presence and rarely including absence data). Indeed, a species´ realized niche, the actually occupied conditions where a species live, may be a subset of their fundamental niche due to lack of habitat availability, constraints on dispersion, and biotic interactions. Here, we produced SDMs for 50 species of neotropical reptiles and amphibians and compared extreme temperature estimates extracted from the modelled area (model-inferred) with thermo-physiological estimates of critical temperatures (physiology-inferred). When comparing experimental critical thermal maximum and minimums with temperature values extracted from the estimated range, we found a general pattern of maximum temperatures experienced that are cooler than the species maximum tolerances, and minimum temperatures close to or even colder than their minimum tolerances. Characterizing niche traits from SDMs is dangerous because SDMs are not representing the fundamental niche of species as measured with thermal physiology limits and they are also not deviating from the fundamental niche in a predictable way.

Objective: To characterize the realized niche of the Mexican spotted owl (Strix occidentalis lucida) and compare the environmental values it uses within the Mexican physiographic provinces.Design/methodology/approach: The environmental temperature variables (n =7), precipitation (n = 7) and elevation (n = 1) were extracted from 79 unique occurrences sites of S. o. lucida. These values were grouped by physiographic provinces: Sierra Madre Occidental (n = 59), Sierra Madre Oriental (n = 13) and Transversal Neovolcanic Belt (n = 6). The climate and elevation of these sites were described and compared via non-parametric Kruskal-Wallis and Bonferroni-Dunn tests (P ? 0.05).Results: The presences of the spotted owls were both, dispersed and focallydistributed, over the geographic space in Mexico. The temperature and elevation variables have similar characteristics in the assessed physiographic provinces. To be noted, the precipitation variables showed significant differences among sites.Limitations on study/implications: This study describes the environmental characteristics of the realized niche of the Mexican spotted owl; however, it isnecessary to investigate other habitat variables at a smaller scale. Findings/conclusions: The temperature and elevation environmentalcharacteristics of the ecological niche of the Mexican spotted owl was similar between physiographic provinces.

This paper addresses the modeling and verification analysis of the mutual relationships among plants, animals, and their environment. We start our study of mathematical ecology by considering the interaction of two species, one of which the predators eat the preys thereby affecting each other, such pairs exist throughout nature: fish and sharks, lions and gazelles, birds and insects, to mention some. Not all species form predator-prey relationships, we can also have the case of a two-species ecosystem in which both species compete for the same limited source of nutrients. If two competitors try to occupy the same realized niche, one species will try to eliminate the other. Therefore, two instances are worth to be considered. On the one hand, there is a need to cooperate sharing part of the resource so that both organisms will benefit from it. On the other hand, if one of the two species is stronger than theother, there will be no cooperation and the strongest species will imposeits conditions. In this work, the ecological interaction system between species is modeled as a formula of the first order logic. Then, using the concept of logic implication, and transforming this logical implication relation into a set of clauses, called Skolem standard form, qualitative methods for verification as well as performance issues, for some queries, are applied.

Arrested succession may lead to losses of productivity and biodiversity in forests after disturbance. In this condition, recalcitrant understory vegetation often dominates over long periods of time and delays forest recovery and succession. Arrested succession has been defined as a type of forest degradation because ecosystem processes and functions that underlie successional dynamics are dramatically reduced. We used the Hutchinson’ niche concept to understand the relative importance of environmental variables that define niche axes of species leading to arrested succession (recalcitrant understory vegetation) and to identify a shift along niche axes that promote the successional progression of long-lived early- and late-seral tree regeneration after partial disturbance due to restoration treatments. We studied Nothofagus old-growth forests in the Chilean Andes, where after selective harvests (i.e., a partial overstory disturbance) the understory is commonly dominated by dense thickets of native bamboo (Chusquea spp.), which has been shown to arrest succession by preventing tree regeneration. To overcome this, sites are typically partially scarified (24 to 45% of the area) following harvest to control bamboo and to encourage early-seral tree regeneration. The partial overstory and ground disturbance leaves a wide array of conditions (environmental gradient) that allowed us to investigate the factors under which a given plant group may regenerate, grow, and dominate the forest. Ordination and niche modeling were used to investigate the niche breadths for bamboo and regenerating tree species, as well as the environmental niche axes at this early successional stage, i.e., eight years after disturbance. The results showed different trends in the shift of centroid and extent of realized niches among three plant groups. For instance, performance of the early-seral group was related to litter cover (–), exposed mineral soil (+) and soil water content (+), which resulted in a niche expansion. In contrast, soil water content affected bamboo (–) and may be responsible for the reduction in realized niche space. Light had less influence on defining niches for tree regeneration during early successional stages. Linking the niche concept to succession provided a simple display of multifaceted issues and thus a better understanding of underlying processes and mechanisms. It provides an example of how application of this concept can help to determine situations in which such regeneration can (or cannot) be established successfully and promote the progression of succession following disturbance. This knowledge provides important insights for designing management and restoration practices based on strong ecological foundations.

Aim. Tropical species are thought to experience and be adapted to narrow ranges of abiotic conditions. This idea has been invoked to explain a broad array of biological phenomena, including the latitudinal diversity gradient and differential rates of speciation and extinction. However, debate continues regarding the broad-scale applicability of this pattern and potential processes responsible. Here, we use a simulation approach to test two propositions: (1) strong geographic patterns of variation in realized niche breadth can arise in the absence of variance in the size of fundamental niches, and (2) realized niche breadths can show latitudinal patterns as a consequence of spatio-temporal climate change, even when fundamental niche breadths are unrelated to latitude, and dispersal abilities are held constant. \ud Location. Global.\ud Time period. Simulations were conducted using climate models from over the last 120 Ka, with trait dynamics captured at 95 Ka and present-day. \ud Major taxa studied. We used virtual species with traits based loosely on plants. \ud Methods. We simulated latitudinal trends of niche breadth and range size for virtual species using a cellular automaton algorithm that linked a gridded geographic domain with a three-dimensional environmental landscape. \ud Results. In all simulations, strong spatial patterns in realized niches were obtained in the absence of niche evolution, and realized niches showed geographic patterns deriving only from real-world spatiotemporal variation in climate. We noted contrasting patterns of niche breadth in different environmental dimensions, with temperature breadth increasing with latitude, but precipitation breadth decreasing with latitude. Overall, simulation outcomes mimicked real-world pattern of latitudinal range extent covarying with amount of land area.\ud Main conclusions. Tropical species can have narrower niche breadths for maximum and minimum temperature ranges compared to temperate species solely as the result of the spatial arrangement of environments. We therefore suggest that the complex spatiotemporal distribution of global abiotic environments has strong potential for structuring observed latitudinal gradients of niche breadths.

Numerous prognoses indicate that climate change will manifest itself in extreme climatic conditions. Therefore, it will be of high importance to know in what extent can plant communities and certain species adapt to altering environmental conditions. Our examinations were implemented in stands of sessile oak common in the Carpathian Basin. The reason behind it has been that, according to climatic models, the realized niche of this species can be reduced by 80% in some regions by 2050. Examinations were made in 3 points of an approximately 400 km long (East-West) transsect crossing the Carpathian Basin: 3 submontane regions of a subatlantic, a continental and a subcarpathian mountain were involved with 5 age groups in each regions. Health status examinations of sessile oaks have been completed by using FAKOPP 3D acoustic tomograph. Among the three venues trees of the subatlantic area were the healthiest; here, the 100 years old age group showed the lowest deterioration, only 0.68%. The most severely deteriorated stands occur in the continental region where the value in the 60 years old age group reached 4.24%. It seems that, besides annual precipitation, the method of planting also influences the health status of stands, since considerable differences could be observed between coppice and seedling stands.

Large veteran trees are key structures sustaining biodiversity in wooded landscapes. Many organisms associated with such trees are, however, also able to inhabit suitable trees with smaller diameters or other surrogate habitats. Understanding the mechanisms behind the importance of veteran trees and the conditions enabling veteran tree specialists to exploit smaller trees might help conservation efforts targeted at the diverse and highly endangered biota associated with veteran trees. To investigate this, we studied local patterns in the exploitation of trees by a veteran tree specialist, the great capricorn beetle (Cerambyx cerdo), at three sites with different soil characteristics, namely floodplain, dry-sandy and dry-rocky sites, where this beetle exploits oaks of large (~1.5 m), medium (~0.75 m) and small (~0.25 m) diameters, respectively. We recorded the presence and number of exit holes made by C. cerdo on each tree and related these to the characteristics of the trees: their diameters, openness of the canopy around them and their state of health. The probability of occurrence and the number of exit holes increased with tree diameter, canopy openness, and decreasing tree health, but these relationships differed considerably among the study sites. In dry conditions, trees of small diameters were more likely to be exploited by the beetle than in the floodplain. The number of exit holes, on the other hand, was a function of tree diameter, with large trees sustaining more beetles and thus acting as larger habitat patches. The species of oak affected the probability of exit hole presence as the sessile oak (Quercus petraea) and pedunculate oak (Q. robur) were preferred over Turkey oak (Q. cerris). The slope orientation also affected the presence of exit holes as trees on slopes with either an eastern or northern orientation were not exploited by the beetle. This study revealed a high level of between-site variability in the tree characteristics relevant to predicting the occurrence of C. cerdo, mainly with respect to diameter. Therefore, while the general patterns of habitat use and the fundamental niche of this beetle are well known, survival and protection of local populations is dependent on site-specific characteristics. The realized niche of this beetle must therefore be carefully considered when planning conservation management for a particular site. The results also signify that at some sites, small trees can, at least temporarily, substitute for scarce large trees if the state of their health is managed using proper conservation measures.

Aim: Observed, realized niche space often underestimates species’ physiological tolerances due to interactions with other species, dispersal constraints, and because some combinations of influential environmental factors do not currently exist in the real world. Conversely, correlative ecological niche models rely on the assumption that the range of environmental conditions encompassed by a species’ geographic distribution accurately reflects their environmental tolerances, including community-level approaches like generalized dissimilarity modelling (GDM). We extend GDM to better understand what effect broader environmental tolerances could have on compositional turnover under climate change. Innovation: We show how GDM can be adjusted as a function of best-available estimates of the average ratio between realized and potential niche widths to modify projected temporal turnover. We demonstrate this approach by using the estimated niche ratios of Australian plant species (n = 7,184) relative to thermal extremes, and the rate at which this ratio varied with temperature. The modified GDMs showed existing thermal tolerance could reduce the turnover predicted by standard models under climate change by up to 11%. We further show how the reduction in expected turnover by 2090 will influence where a greater proportion of the current community will persist in a region. Main conclusions: We suggest that standard spatial GDMs and their modified versions represent the extremes of ecological niche perspectives (i.e., realized and potential) and the range of tolerance communities may have when responding to environmental change. GDM projections therefore identify the range of uncertainty associated with a critical model assumption, and as climate change continues, ongoing community monitoring could be used to validate the balance between the two possibilities.

Because plant roots serve mainly as organs for the uptake of water and nutrients, we aimed to test whether the development of seedling roots is influenced by the two principal nutrient sources—the substrate and the pool stored in the seed itself. Using seven Fabaceae species that differ in seed mass, we observed their early root system development under four levels of nutrient availability. Transparent-wall rhizoboxes allowed us to track root development and to score root system structure (length and number of roots), size (depth and width of root system) and shape (relative depth and width of root system). Seedling root system development depended on both the amount of nutrients contained in the substrate and on the seed mass of the species. Compared to an average seedling, effects of these two nutrient pools were (i) opposite and (ii) did not fully overlap. Small-seeded species developed wider root systems that branched earlier than large-seeded species. Increased availability of nutrients in the substrate led to proliferation of lateral roots, without any substantial impacts on the shape of root system or beginning of branching. The source of the nutrients affected the way they were used throughout early root system development, leading to different structures and dynamics. This may be one of the mechanistic links connecting seed mass and the realized niche of the species.

Gradient studies of wetland forests have inferred that competition from upland tree species confines waterlogging-tolerant tree species to hydric environments. Little is known, however, about competition effects on individual-tree growth along stress gradients in wetland forests. We investigated tree growth and competition in mixed-species stands representing a waterlogging stress gradient in Fraxinus nigra Marsh. (black ash) forests in Minnesota, USA. Using competition indices, we examined how F. nigra basal area increment (BAI) responded to competition along the gradient and whether competition was size-asymmetric (as for light) or size-symmetric (as for soil resources). We modeled spatial distributions of F. nigra and associated tree species to assess how variation in species mixtures influenced competition. We found that although F. nigra BAI did not significantly differ with variations in site moisture, the importance of competition decreased as waterlogging stress increased. Competition across the gradient was primarily size-asymmetric (for light). Variation in species mixtures along the gradient was an important influence on competition. Some segregation of tree species occurred at all but the most upland site, where waterlogging stress was lowest and evidence of competition was greatest, confirming that competition from upland tree species confines F. nigra and potentially other waterlogging-tolerant species to hydric environments.

Aim Higher elevation habitats contribute substantially to global biodiversity. Nevertheless, we know comparatively little about how diversity patterns differ among alpine and montane communities across different mountain ranges. Here, we characterized the realized niche space of American seed plants to ask whether or not montane or alpine community compositions define climatically distinct species pools at this regional scale. Location Americas. Time Period Contemporary. Major taxa studied Seed plants. Methods We assembled a niche model dataset of 72,372 American seed plants based on digitized and georeferenced specimen records. We used this dataset to quantify occupied abiotic niche space with regards to temperature, precipitation, and elevation. This approach further permitted differentiation of higher-elevation specialists (i.e., ranges centered at high elevations) from generalists (i.e., ranges centered at lower elevations but extending into mountain areas). Results Montane communities did not differ from the regional species pool in terms of richness patterns, occupied climatic niche space, or niche breadth. In contrast, alpine communities were characterized by a bimodal latitudinal diversity gradient, drastically reduced climatic niche space, and broader temperature but narrower precipitation niche breadth. Alpine generalists further showed statistically significant differences in temperature, but not precipitation, niche breadth from both alpine specialists and lowland taxa. We also highlight non-alpine species whose climatic niche space otherwise overlapped with that of alpine plants. These species were geographically concentrated in the southern US and Mexico, tended to have a greater fraction of their ranges in frost-exposed mountain foothills, and less of their range in lowland, frost-free, areas, compared to other non-alpine species. Main conclusions These results suggest that ecological and physiological barriers, rather than dispersal limitation might better explain alpine community assembly and that alpine, but not montane, communities form a climatically distinct species pool in the Americas.

A survey of six common grouper (Serranidae) species was conducted on both the western protected and eastern unprotected reefs around Chumbe Island, Zanzibar. Species, estimated maturity, and habitat were recorded using standardized categories. Fundamental niche and general habitat preference were extrapolated based on observed realized niche and qualified based on substrate, depth, slope position, and general reef region. Taking habitat preference into account, abundance and biomass density of serranid populations were compared between locations on the reef in order to best account for how habitat influences distribution and population health. The results of this study provide depth to previous research on the protected reef and indicate noteworthy shifts in population composition between 2014 and 2018 that favour species with less specified habitat preference, such as Aethaloperca rogaa and Cephalopholis argus. Surveys of Chumbe’s nearby unprotected eastern reef indicate low levels of species abundance, which this study hypothesizes is the result of inappropriate habitat structure, increased fishing pressure, and decreased population health within the MPA. Ultimately, this study suggests that MPAs do not protect all species equally, and habitat preference must be taken into account when assessing MPA effectiveness at protecting different species. Indeed, especially as serranid habitat faces continued degradation, serranid conservation will depend even more on protection of each species’ preferred habitat in coral systems. As such, assessing serranid populations as a whole fails to capture the changes in population distribution and composition that is occurring between species, which may be more indicative of shifts and disturbances in the ecosystem.

Current trends emphasize the importance of the examination of the functional composition of lichens, which may provide information on the species realized niche diversity and community assembly processes, thus enabling one to understand the specific adaptations of lichens and their interaction with the environment. We analyzed the distribution and specialization of diverse morphological, anatomical and chemical (lichen secondary metabolites) traits in lichen communities in a close-to-natural forest of lowland Europe. We considered these traits in relation to three levels of forest ecosystem organization: forest communities, phorophyte species and substrates, in order to recognize the specialization of functional traits to different levels of the forest complexity. Traits related to the sexual reproduction of mycobionts (i.e., ascomata types: lecanoroid apothecia, lecideoid apothecia, arthonioid apothecia, lirellate apothecia, stalked apothecia and perithecia) and asexual reproduction of mycobionts (pycnidia, hyphophores and sporodochia) demonstrated the highest specialization to type of substrate, tree species and forest community. Thallus type (foliose, fruticose, crustose and leprose thalli), ascospore dark pigmentation and asexual reproduction by lichenized diaspores (soredia and isidia) revealed the lowest specialization to tree species and substrate, as well as to forest community. Results indicate that lichen functional trait assemblage distribution should not only be considered at the level of differences in the internal structure of the analyzed forest communities (e.g., higher number of diverse substrates or tree species) but also studied in relation to specific habitat conditions (insolation, moisture, temperature, eutrophication) that are characteristic of a particular forest community. Our work contributes to the understanding of the role of the forest structure in shaping lichen functional trait composition, as well as enhancing our knowledge on community assembly rules of lichen species.

Dinophysis acuta and D. acuminata are associated with lipophilic toxins in Southern Chile. Blooms of the two species coincided during summer 2019 in a highly stratified fjord system (Puyuhuapi, Chilean Patagonia). High vertical resolution measurements of physical parameters were carried out during 48 h sampling to i) explore physiological status (e.g., division rates, toxin content) and ii) illustrate the fine scale distribution of D. acuta and D. acuminata populations with a focus on water column structure and co-occurring plastid-bearing ciliates. The species-specific resources and regulators defining the realized niches (sensu Hutchinson) of the two species were identified. Differences in vertical distribution, daily vertical migration and in situ division rates (with record values, 0.76 d−1, in D. acuta), in response to the environmental conditions and potential prey availability, revealed their niche differences. The Outlying Mean Index (OMI) analysis showed that the realized niche of D. acuta (cell maximum 7 × 103 cells L−1 within the pycnocline) was characterized by sub-surface estuarine waters (salinity 23 – 25), lower values of turbulence and PAR, and a narrow niche breath. In contrast, the realized niche of D. acuminata (cell maximum 6.8 × 103 cells L−1 just above the pycnocline) was characterized by fresher (salinity 17 – 20) outflowing surface waters, with higher turbulence and light intensity and a wider niche breadth. Results from OMI and PERMANOVA analyses of co-occurring microplanktonic ciliates were compatible with the hypothesis of species such as those from genera Pseudotontonia and Strombidium constituting an alternative ciliate prey to Mesodinium. The D. acuta cell maximum was associated with DSP (OA and DTX-1) toxins and pectenotoxins; that of D. acuminata only with pectenotoxins. Results presented here contribute to a better understanding of the environmental drivers of species-specific blooms of Dinophysis and management of their distinct effects in Southern Chile. Previous article

Physiological studies contribute to a cause and effect understanding of ecological patterns under climate change and identify the scope and limits of adaptation. Across most habitats, this requires analyzing organism responses to warming, which can be modified by other drivers such as acidification and oxygen loss in aquatic environments or excess humidity or drought on land. Experimental findings support the hypothesis that the width and temperature range of thermal performance curves relate to biogeographical range. Current warming causes range shifts, hypothesized to include constraints in aerobic power budget which in turn are elicited by limitations in oxygen supply capacity in relation to demand. Different metabolic scopes involved may set the borders of both the fundamental niche (at standard metabolic rate) and the realized niche (at routine rate). Relative scopes for aerobic performance also set the capacity of species to interact with others at the ecosystem level. Niche limits and widths are shifting and probably interdependent across life stages, with young adults being least thermally vulnerable. The principles of thermal tolerance and performance may also apply to endotherms including humans, their habitat and human society. Overall, phylogenetically based comparisons would need to consider the life cycle of species as well as organism functional properties across climate zones and time scales. This Review concludes with a perspective on how mechanism-based understanding allows scrutinizing often simplified modeling approaches projecting future climate impacts and risks for aquatic and terrestrial ecosystems. It also emphasizes the usefulness of a consensus-building process among experimentalists for better recognition in the climate debate.

Freshwater fish must maintain the concentration of salts in their blood within a narrow range, but this status is challenged by the prevailing water chemistry and its fluctuations. This paper provides a framework for understanding how fish in nature will respond to forecasted future changes in water chemistry., Alterations in water chemistry can challenge resident fish species. More specifically, chemical changes that disrupt ion balance will negatively affect fish health and impact physiological and ecological performance. However, our understanding of which species and populations are at risk from ionoregulatory disturbances in response to changing freshwater environments is currently unclear. Therefore, we propose a novel framework for incorporating ionoregulatory physiology into conservation management of inland fishes. This framework introduces the concepts of fundamental chemical niche, which is the tolerable range of chemical conditions for a given species based on laboratory experiments, and realized chemical niche, which is the range of chemical conditions in which a species resides based on distribution surveys. By comparing these two niches, populations that may be at risk from ionoregulatory disturbances and thus require additional conservation considerations can be identified. We highlight the potential for commonly measured ionoregulatory traits to predict fundamental and realized chemical niches but caution that some traits may not serve as accurate predictors despite being important for understanding ionoregulatory mechanisms. As a sample application of our framework, the minimum pH distribution (realized niche) and survival limit pH (fundamental niche) of several North American fishes were determined by systematic review and were compared. We demonstrate that ionoregulatory capacity is significantly correlated with a realized niche for many species, highlighting the influence of ionoregulatory physiology on fish distribution patterns along chemical gradients. Our aim is that this framework will stimulate further research in this field and result in a broader integration of physiological data into conservation management decisions for inland waters.

Organisms and their resident microbial communities - the microbiome - form a complex and mostly stable ecosystem. It is known that the composition of the microbiome and bacterial species abundances can have a major impact on host health and Darwinian fitness, but the processes that lead to these microbial patterns have not yet been identified. We here apply the niche concept and trait-based approaches as a first step in understanding the patterns underlying microbial community assembly and structure in the simple metaorganism Hydra. We find that the carrying capacities in single associations do not reflect microbiota densities as part of the community, indicating a discrepancy between the fundamental and realized niche. Whereas in most cases, the realized niche is smaller than the fundamental one, as predicted by theory, the opposite is observed for Hydra’s two main bacterial colonizers. Both, Curvibacter sp. and Duganella sp. benefit from association with the other members of the microbiome and reach higher fractions as compared to when they are the only colonizer. This cannot be linked to any particular trait that is relevant for interacting with the host or by the utilization of specific nutrients but is most likely determined by metabolic interactions between the individual microbiome members.

Kelps are canopy-forming brown seaweed sustaining critical ecosystem services in coastal habitats, including shelter, nursery grounds, and providing food resources to a myriad of associated species. This study modeled the fundamental niche of Laminaria abyssalis along the Brazilian continental margin, an endemic species of the South Atlantic, to anticipate potential distributional range shifts under two contrasting scenarios of future environmental changes (RCP2.6 and RCP8.5). The model for fundamental niche predictions considering the "present scenario" has shown a wider potential area than the realized niche (i.e., the area where the species actually occurs) along the Brazilian coast. In both future scenarios, the models have shown niche erosion on the northern portion of the Brazilian coast and niche gains towards the south. In both scenarios, L. abyssalis populations tend to shift to deeper regions of the reef. The restricted range of occurrence (33,000 km2), intense anthropic activities along these beds (e.g., trawling fisheries, oil/gas mining, or removal for agricultural purposes) acting synergically with global warming, may drive this ecosystem to collapse faster than kelp species' ability to adapt. We propose to classify L. abyssalis as Endangered - (EN) under IUCN criteria, and highlight that long-term monitoring of kelp beds is an urgent need to develop effective conservation initiatives to protect such rare and invaluable ecosystem. FCT: UID/Multi/04326/2019, PTDC/MAR-EST/6053/2014, SFRH/BSAB/150485/2019, PTDC/BIA-CBI/6515/2020 info:eu-repo/semantics/acceptedVersion

Islands have been widely recognized as natural laboratories in ecological and evolutionary studies (1, 2). Compared to mainland species, species endemic to islands (i.e., island endemics) may only occupy a small part of their fundamental niche due to dispersal limitation caused by surrounding water (3). When being introduced to new areas, island endemics very likely expand their realized niche as a consequence of the increased availability of suitable environments (3). Understanding such niche changes of island endemics is not only important for predicting their future distribution in areas where they were introduced but also for anticipating the response of other species with limited distributions … [↵][1]1To whom correspondence may be addressed. Email: liuchunlong113{at}gmail.com. [1]: #xref-corresp-1-1

Zonation along a water level is the main spatial distribution characteristic of wetland plants. This is mainly because of the influences of hydrological conditions and interspecific competition, which finally narrow the fundamental niche of a species to its realized niche. In the present study, a controlled experiment was conducted in order to analyze the relationship between Carex lasiocarpa/Carex pseudocuraica and Glyceria spiculosa, in conditions of three competitive treatments at four water levels. The results showed that in no competition, C. lasiocarpa preferred low water levels, but this preference receded when competing with G. spiculosa. In contrast, C. pseudocuraica had greater preference for low water level when competing with G. spiculosa. The root/shoot ratios of the two Carex species decreased with increasing water levels, but they were almost unaffected by different competition treatments. With the increase in water level during full competition with G. spiculosa, the competitive ability of C. lasiocarpa showed an increasing trend, whereas a contrary trend was observed in C. pseudocuraica. Our results suggested the effects of water levels and their interactions with interspecific competition varied between the two Carex species and played an important role in determining spatial distribution patterns and potential community succession of wetland plants.

ion for their problem definitions and avoid over-constraining the solution space (Ulrich, 2011). If designers analyze the end-user’s goals independent of any particular artifact-to-be-designed, they can begin the design process with the maximum breadth of solution space, increasing flexibility and delaying costly decisions. Explicitly linking required affordances to high-level goals builds system-level verification and validation opportunities into a design scenario, especially if those goals require execution of a plan involving many behaviors. This can help avoid situations in which individual affordance-level tests (e.g.,to 87 determine if a particular low-level action or behavior can be performed) fail to capture behavior that emerges or fails to emerge after system integration. Goal-level needs specifications are more general than behavior-level requirements because unlike behaviors, goals are purely intentional concepts and therefore more solution-agnostic. It is possible that early-stage design requirements specified at the behavioral level are more likely to act as a cognitive anchor during solution ideation. This is particularly true if the behavioral specifications are linked to the physical structure of existing solutions, such as defining the need for a more efficient car when the user’s real desire was a less expensive commute to work. Developing requirements in terms of goals allows designers to specify constraints on candidate designs with a minimum of information about the form of the solution. For example, the solution to a particular design problem might be a product to be sold, a product-service system, or simply training users to exercise new abilities. Lastly, goal-level specifications are necessary from the perspective of design-as-nichemodification. Because a niche is the set of affordances that a type of organism uses, modifying those affordances changes the niche. Without a goal-level requirement specification we are left without a means of identifying or comparing niches. If a fundamental niche consists of the variety of ways in which a particular goal can be achieved by a particular type of organism, and a realized niche is the specific set of affordances and affordance carriers used by that organism (Hutchinson, 1978), then Houkes and Vermass’ plan-based model of artifact use provides a graduated framework for describing niche alteration (Table 1). By altering Realized niche Fundamental Niche Goals Different niche type Different niche type Only actions (same goals) Different niche type Unaltered Only artifacts used (same actions, goals) Different niche type Unaltered Actions and artifacts (same goals) Different niche type Unaltered Table 1: Altering different elements of a use-plan results in different types of niche changes Our approach to a niche-based analysis of design is therefore based on decomposing use scenarios to understand how individuals currently achieve particular goals, followed by an analysis of how and why niche parameters can be altered by designers. While our immediate goal is the development of a framework 88 for understanding the design process, we also recognize the utility of this approach for designers themselves. For a designer, niche analysis represents a structured, holistic means for identifying and describing design opportunities. The core of our approach involves collecting sufficient information to specify the relevant niches for a particular artifact. Because of artifact non-exclusivity and multiplicity, artifacts can be part of multiple niches throughout their life-cycle because they provide affordances to multiple types of individuals. Because of boundedness, these niches can be identified and evaluated in terms of a single circumscribing niche. For an ecological approach to design to be complete, it is necessary to be able to define this circumscribing niche and account for all sub-niches relevant to the design, creation, and use of the artifact. For designers engaged in the design process, it may only be necessary to consider particular niches, such as end-use or a specific manufacturing process. Niche definitions should begin by identifying the niche inhabitants, such as an artifact’s user or intended type of user. For the analysis of existing artifacts one has the opportunity to directly identify the artifact’s users. For the identification of design opportunities, one must specify an intented type of user. Users can be usefully described in both functional and parametric terms. Functional user descriptions focus on the user’s behavioral abilities, which determine the affordances available to them in a particular environment. Parametric user descriptions may be affordance-defining ergonomic data like leg length (Warren, 1984) or demographic data such as socioeconomic class, geographical location, and cultural background. As Gibson (1979) noted, social and interpersonal affordances are extremely important for humans, and play a large role in day-to-day goal achievement. Social relationships, attitudes, and expectations may differ significantly between different cultures (Gaver, 1991), which may alter the existence of interpersonal affordances. Specifying the user’s goals determines the type of niche. For design purposes, goals should be described in observer-independent terms about the user’s existing or desired situation. Defining goals as minimally as possible without sacrificing specificity will help avoid over-constraining the design space. For a given overall goal there may exist subgoals, and the principle of artifact non-exclusivity implies that these goals may be used to define sub-niches.

An understanding of how ecological niches can change through time is key to predicting the effect of future global change. Past climatic fluctuations provide a natural experiment to assess the extent to which species can change their niche. Here we use an extensive archaeological database to formally test whether the niche of four European ungulates changed between 40 and 8 kya (i.e. before major anthropogenic habitat modification and excluding the confounding effect of domestication). We find that niche change depended on habitat. Horse and aurochs, which are adapted to open environment, changed their niche after the Last Glacial Maximum, and it is unclear whether this was the result of adaptation, or an expansion of the realized niche as a response to the extinction of other megafauna (competitors and predators) that shared the same habitat preferences. On the other hand, red deer and wild boar, which prefer close and semi-close habitats, did not change their niche during the same period; possibly because these habitats have experienced fewer extinctions. Irrespective of the mechanism that might have led to the observed niche changes, the fact that large mammals with long generation times can change their niche over the time period of thousands of years cautions against assuming a constant niche when predicting the future.Significance statementWhen predicting species responses to future change, it is often assumed that their habitat preferences (i.e. their niche) will not change. However, it is strongly debated whether this is reasonable. Here we show that two out of four species of large European ungulates changed their niche following the Last Glacial Maximum, possibly as a response to the reorganization of animal communities that resulted from numerous megafauna extinctions. This finding cautions against the assumption of a constant niche, highlighting that, to predict the future, we will ultimately need to understand the mechanisms that underpin the success of a given species under different climatic conditions.

Studies that question important conceptual and methodological aspects of the field of ecological niche modeling (and species distribution modeling) have cast doubts on whether it is possible to estimate the fundamental niche of a species using presence-only data. The main limitation in niche estimation is that presence data come from the realized niche, which is only a subset of the fundamental niche. Most of the existing methods lack the ability to overcome this limitation and therefore fit niches that resemble the realized niche. To obtain a more accurate estimate of the fundamental niche, we propose using the geographic region that is accessible to a species (based on its dispersal ability) to determine a sampling distribution, in environmental space, from which we can quantify the likelihood of observing a particular environmental combination in a sample of presence points. We incorporate this sampling distribution into a multivariate normal model (i.e., a Mahalanobis distance model) by creating a weight function that modifies the probabilities of observing different environmental combinations in a sample of presences. This modification accounts for the uneven availability of environmental conditions. We show that the parameters of this weighted-normal model can be approximated with a maximum likelihood estimation approach; and then used to draw ellipsoids (confidence regions) that represent the fundamental niche of the species. We illustrate the application of our model with two worked examples. First, we use presence data for an invasive species and an accessible area that includes only its native range to evaluate whether the fitted model predicts confirmed establishments of the species outside its native range. Second, we use presence data for closely related species with known accessible areas to demonstrate how the different dispersal abilities of the species constrain a classic Mahalanobis distance model. Overall, we show that accounting for the distribution of environmental conditions that are accessible to a species indeed affects the estimation of the ellipsoids used to model its fundamental niche.

It is deemed important to understand cetacean occurrence and distribution to comprehend their ecological roles. The geographical occurrence of species’ niche can be used to better describe their potential distribution. The niche can be defined using environmental variables. Those variables are considered static and not affected by biological activities. The present study goal was to assess the occurrence and distribution of cetaceans along the southeastern Brazilian coast, as well as to define the fundamental and realized niche of each species and to investigate niche overlap at local scale. The environmental requirements for each species were also investigated throughout statistical tests. Sighting data were obtained through oceanographic surveys conducted between 2012 and 2015. The environmental variables available on MARSPEC and the software NicheA were used for the ecological niche modeling. A total of twelve cetacean species were identified and the potential distribution areas of the six commonest ones were defined. Even though the species presented different environmental preferences, most of them had partial overlap among niches and potential distribution areas. The environmental heterogeneity of the study area might support the co-occurrence of different species with different environmental requirements.

Background and Aims Facilitation is an important ecological process for plant community structure and functional composition. Although direct facilitation has accrued most of the evidence so far, indirect facilitation is ubiquitous in nature and it has an enormous potential to explain community structuring. In this study, we assess the effect of direct and indirect facilitation on community productivity via taxonomic and functional diversity. Methods In an alpine community on the Tibetan Plateau, we manipulated the presence of the shrub Dasiphora fruticosa and graminoids in a fenced meadow and a grazed meadow to quantify the effects of direct and indirect facilitation. We measured four plant traits: height, lateral spread, specific leaf area (SLA) and leaf dry matter content (LDMC) of forbs; calculated two metrics of functional diversity [range of trait and community-weighted mean (CWM) of trait]; and assessed the responses of functional diversity to shrub facilitation. We used structural equation modelling to explore how shrubs directly and indirectly drove community productivity via taxonomic diversity and functional diversity. Key Results We found stronger effects from herbivore-mediated indirect facilitation than direct facilitation on productivity and taxonomic diversity, regardless of the presence of graminoids. For functional diversity, the range and CWM of height and SLA, rather than lateral spread and LDMC, generally increased due to direct and indirect facilitation. Moreover, we found that the range of traits played a primary role over taxonomic diversity and CWM of traits in terms of shrub effects on community productivity. Conclusions Our study reveals that the mechanism of shrub direct and indirect facilitation of community productivity in this alpine community is expanding the realized niche (i.e. expanding range of traits). Our findings indicate that facilitators might increase trait dispersion in the local community, which could alleviate the effect of environmental filters on trait values in harsh environments, thereby contributing to ecosystem functioning.