Environmental Niche Models Research Articles

Towards an Integrated Biodiversity Technology Program Supporting Transparent Decision Making in Australia

Effective management of our natural world under current and future conditions requires efficient, collaborative and complementary planning and decision-making processes with clear lines of accountability. While there has been significant progress in establishing national databases for the management of species observation data, these only represent samples of a species' total distribution. The need and challenge therefore is to model these point-based observation data to obtain estimates or projections of the total range and distribution of the species. Such Species Distribution Models (SDMs), also known as Environmental Niche Models (ENMs), and the geographic data (or “maps”) they generate, provide vital information needed by governments at all levels to meet various policy and statutory responsibilities and obligations. SDMs quantify the response of species occurrence to environmental conditions described by variables such as climate, substrate, productivity and vegetation. The outcomes of an SDM can be used to identify locations and regions with potentially suitable environmental conditions for a species, as well as assess how species may respond to projected future climate changes or habitat loss. While SDMs are widely used in many decision- and policy-making programs, investment in species distribution information has been fragmented and limited. In Australia, three different government departments joined forces with the Atlas of Living Australia and the Biodiversity and Climate Change Virtual Laboratory to develop a standard framework for modelling threatened species distributions for use in policy and environmental decision-making. The pilot program that will be conducted throughout 2019 includes three complementary pillars: An expert panel with both researchers and government practitioners who will review current SDM practices used in government and develop a set of best-practice methods. A technology program that includes the development of a new modelling platform that implements the best-practice methods for transparent and reproducible SDMs for decision making as established by the expert panel. Additionally, there will be an online portal for publishing ecological model outputs in a searchable catalogue to enhance cross-jurisdiction collaborations. Establishment of a training and skill development program to upskill decision makers using the new tools and methodology in practice. An expert panel with both researchers and government practitioners who will review current SDM practices used in government and develop a set of best-practice methods. A technology program that includes the development of a new modelling platform that implements the best-practice methods for transparent and reproducible SDMs for decision making as established by the expert panel. Additionally, there will be an online portal for publishing ecological model outputs in a searchable catalogue to enhance cross-jurisdiction collaborations. Establishment of a training and skill development program to upskill decision makers using the new tools and methodology in practice. This presentation will showcase the outcomes of this program and highlight how digital infrastructure can enhance decision making. In this case specifically, the collaboration across government departments ensures a) a consistent approach across jurisdictions, b) an increase in model quality, thereby leading to a decrease in unnecessary survey or consultation efforts, c) an increase in suitability, robustness and reproducibility of SDMs, and d) increased advocacy and coordination in national programs and resources.

Current and future climatic regions favourable for a globally introduced wild carnivore, the raccoon Procyon lotor

Invasive species are considered as one of the major threats to biodiversity and represent a major challenge in the conservation of natural ecosystems, in preventing damage to agricultural production, and human health risks. Environmental Niche Modelling has emerged as a powerful tool to predict the patterns of range expansion of non-native species and to direct effective strategies for managing biological invasions. The raccoon, Procyon lotor, is a wild mesocarnivore presenting a high adaptability and showing successful introduced populations worldwide. Here, we modelled the current and future climatically favourable areas for the raccoon using two protocols, based on data sets filtrated in geographic and environmental spaces. Projections from these models show extensive current favourable geographical areas covering extensive regions of temperate biomes. Moreover, predictions for 2050 reveals extensive new favourable areas north of the current favourable regions. However, the results of the two modeling approaches differ in the extent of predicted favourable spaces. Protocols using geographically filtered data present more conservative forecasts, while protocol using environmental filtration presents forecasts across greater areas. Given the biological characteristics and the ecological requirements of a generalist carnivore such as the raccoon, the latter forecasts appears more relevant and should be privileged in the development of conservation plans for ecosystems.

Genetic variation of the most abundant forest‐dwelling rodents in Central Africa (Praomys jacksoni complex): Evidence for Pleistocene refugia in both montane and lowland forests

AbstractAimWe investigate the Plio‐Pleistocene evolutionary history of one of the most abundant rodents in Afrotropical forests. Specifically, we ask how their diversification was influenced by climate change, topography and major rivers.LocationTropical Africa: Lower Guinea (including Cameroon volcanic line; CVL), Congolia, Albertine Rift (AR), Kenyan highlands (KH).TaxonMurine rodents of the Praomys jacksoni complex.MethodsWe used 849 genotyped individuals to describe the overall diversity and spatial genetic structure across a majority of their known distribution area. The combination of one mitochondrial and three nuclear markers was used to infer dated phylogenies using Bayesian and maximum likelihood approaches. Genetic structure was further assessed by multispecies coalescent species delimitation. Current and past distributions of particular taxa were predicted using environmental niche modelling.ResultsThe complex is composed of five major genetic clades (proposed species). Two of them are restricted to specific habitat types (either montane forests of AR or wetlands in lowland forests along the Congo River), three others have wide geographic distributions and lower levels of ecological specialization. The earliest divergence is dated to the Plio‐Pleistocene boundary and is in accordance with the separation of AR forests and Guineo‐Congolian forests. Further diversification of the complex is associated with Pleistocene climate changes. Relatively stable refugia of suitable climatic conditions were identified in lowland Congolia (for two species currently distributed only in lowland forests) as well as in montane forests of CVL, AR, KH (playing the role of reservoirs of diversity). Large rivers, especially the Congo River, are important barriers to gene flow for most taxa, but probably were not the primary cause of differentiation.Main conclusionsThe evolutionary history of the complex was primarily affected by Pleistocene climate changes and diversification in forest refugia. There is little support for ecological parapatric speciation or the riverine barrier hypothesis.

Phylogeography, classification and conservation of pink zieria (Zieria veronicea; Rutaceae): influence of changes in climate, geology and sea level in south-eastern Australia

We assessed genetic variation in the Australian shrub Zieria veronicea across its current distribution and used environmental niche modelling to predict its distribution at the Last Glacial Maximum (LGM). The species range, from Kangaroo Island in South Australia to northern Tasmania, includes substantial overland and marine disjunctions of up to ~ 500 km. By inferring historical patterns of connectivity and genetic differentiation from DNA sequences and AFLP data, we aimed to provide new insight into the history of the species-rich sclerophyll vegetation in south-eastern Australia. Genetic differentiation of populations was not correlated with the size of geographic disjunctions. The deepest genetic divergence was between populations on Kangaroo Island and the adjacent mainland, separated by a strait only 13 km wide. Populations in western Victoria and Tasmania, separated by the 300 km of Bass Strait, showed the lowest genetic differentiation. This pattern is consistent with dispersal of Z. veronicea into Tasmania, across the Bassian Plain, possibly as recently as the LGM, in line with inferred distribution at that time. Genetic patterns, soil ages and niche models support Quaternary colonisation of the lower Murray Basin, potentially from eastern South Australia. The history of a large (500 km) disjunction between populations in western and eastern Victoria is unclear; historical connectivity of populations through suitable habitats is assumed, but the timing and location of connections are not clear. Genetic data support the current recognition of two subspecies and their treatment as distinct entities under conservation legislation.

Climate variability impacts on diversification processes in a biodiversity hotspot: a phylogeography of ancient pseudoscorpions in south-western Australia

Abstract The south-western division of Australia is the only biodiversity hotspot in Australia and is well-known for extreme levels of local endemism. Climate change has been identified as a key threat for flora and fauna, but very few data are presently available to evaluate its impact on invertebrate fauna. Here, we derive a molecular phylogeography for pseudoscorpions of the genus Pseudotyrannochthonius that in the south-west are restricted to regions with the highest rainfall. A dated molecular phylogeny derived from six gene fragments is used for biogeographic reconstruction analyses, spatial mapping, environmental niche-modelling, and to infer putative species. Phylogenetic analyses uncover nine clades with mostly allopatric distributions and often small linear ranges between 0.5 and 130 km. Molecular dating suggests that the origins of contemporary diversity fall into a period of warm/humid Palaeogene climates, but splits in the phylogeny coincide with major environmental shifts, such as significant global cooling during the Middle Miocene. By testing several models of historical biogeography available for the south-west, we determine that Pseudotyrannochthonius is an ancient relict lineage that principally follows a model of allopatric speciation in mesic zone refugia, although there are derivations from this model in that some species are older and distribution patterns more complex than expected. Ecological niche models indicate that drier and warmer future climates will lead to range contraction towards refugia of highest rainfall, probably mimicking past variations that have generated high diversity in these areas. Their conservation management will be crucial for preserving the unique biodiversity heritage of the south-west.

Phylogeography and niche modelling: reciprocal enlightenment

Abstract Phylogeography examines the spatial genetic structure of species. Environmental niche modelling (or ecological niche modelling; ENM) examines the environmental limits of a species’ ecological niche. These two fields have great potential to be used together. ENM can shed light on how phylogeographical patterns develop and help identify possible drivers of spatial structure that need to be further investigated. Specifically, ENM can be used to test for niche differentiation among clades, identify factors limiting individual clades and identify barriers and contact zones. It can also be used to test hypotheses regarding the effects of historical and future climate change on spatial genetic patterns by projecting niches using palaeoclimate or future climate data. Conversely, phylogeographical information can populate ENM with within-species genetic diversity. Where adaptive variation exists among clades within a species, modelling their niches separately can improve predictions of historical distribution patterns and future responses to climate change. Awareness of patterns of genetic diversity in niche modelling can also alert conservationists to the potential loss of genetically diverse areas in a species’ range. Here, we provide a simplistic overview of both fields, and focus on their potential for integration, encouraging researchers on both sides to take advantage of the opportunities available.

Specific habitat requirements and niche conservatism for nine species of the Mexican genus Thelocactus (Cactaceae)

Although Mexican Cactaceae are a significative component of Mexican flora and have a relevant economic and ornamental value, the knowledge of the environmental factors characterizing their niche is still rather limited. This study was aimed at defining the ecological niche and potential distribution of 9 species of the genus Thelocactus . Climatic and topographic variables constraining the distribution of Thelocactus species were identified by means of environmental niche models (ENM) and ordination techniques and used to generate potential distribution maps. The constructed ENMs were compared to assess the similarities of the ecological niche of Thelocactus species and to know if they share the same ecological niche space. The distribution of Thelocactus species was mostly limited by isothermality and precipitation of wettest quarter. The differences in habitat requirements were well documented by the significative differences in the niche ecological space as shown by the equivalency test, while the high percentage of niches that were more similar than expected by chance suggest a high degree of niche conservatism among Thelocactus species. The spatial predictions could serve to improve field design sampling to discover new populations, while niche characteristics could be relevant for improving preservation actions and guiding reintroduction programs for a better conservation of Thelocactus species.

Morphological, genetic and epigenetic aspects of homoploid hybridization between Salvia officinalis L. and Salvia fruticosa Mill.

The inheritance of phenotypic, genetic and epigenetic traits in hybridization events is difficult to predict, as numerous evolutionary, ecological, and genetic factors can play a crucial role in the process of hybridization. In the middle Adriatic island of Vis, we investigated hybridization between Salvia officinalis and S. fruticosa at morphological, genetic and epigenetic levels. SSR results revealed that hybrid individuals were characterized by diploid set of chromosomes suggesting homoploid hybridization. A well-defined group that mostly comprised of F1 generation individuals was detected. For the majority of analysed morphological characteristics, hybrids were placed in-between parental taxa, while at the same time, values of different genetic parameters were mostly higher in hybrids than in parental species. The results revealed a high contrast in the levels of phenotypic variability and epigenetic excitation between parental taxa. Environmental niche modelling confirmed that in the studied location S. officinalis experiences optimal climatological conditions, while S. fruticosa struggles with unsuitable conditions. Very low levels of gene flow between the parental species were detected. In addition, contrasting levels of epigenetic excitation in the studied groups clearly demonstrated the importance of an epigenetic response to an altered environment and confirmed the trans-generational nature of the epigenetic changes.

Compound-specific δ15N values express differences in amino acid metabolism in plants of varying lignin content

Amino acid δ15N values of foliage of various plant taxa, grown at the experimental farm stations of North Wyke, UK and Bad Lauchstädt, Germany were determined by GC-C-IRMS. The difference between δ15N values of glutamate (Glx) and phenylalanine (Phe) were found to differ significantly between woody and herbaceous plants, with mean Δ15NGlx-Phe (i.e. δ15NPhe - δ15NGlx) values of −9.3 ± 1.6‰ and −5.8 ± 2.1‰, respectively. These differences in values are hypothesised to be due to the involvement of Phe in the phenylpropanoid pathway, by which lignin and other phenolic secondary metabolites are produced, leading to isotopic fractionation and enrichment of the remaining Phe pool available for protein biosynthesis. This results in the more negative Δ15NGlx-Phe values observed in woody plants relative to herbaceous plants, as the former are assumed to produce more lignin. To test this assumption, plant leaf tissue lignin concentrations were estimated by solid state 13C cross-polarisation, magic-angle-spinning (CPMAS) NMR spectroscopy for a subset of plants, which showed that tree foliage has a higher concentration of lignin (12.6 wt%) than herbaceous foliage (6.3 wt%). The correlation of lignin concentration with Δ15NGlx-Phe values demonstrates that the difference in these values with plant type is indeed due to differential production of lignin. The ability to estimate the lignin content of plants from amino acid δ15N values will, to give one example, allow refinement of estimates of herbivore diet in present and past ecosystems, enabling more accurate environmental niche modelling.

Similar but different: Revealing the relative roles of species‐traits versus biome properties structuring genetic variation in South American marsh rats

AbstractAimWetland habitats, and the ecological restrictions imposed by them, structure patterns of genetic variation in constituent taxa. As such, genetic variation may reflect properties of the specific biomes species inhabit, or shared life history traits among species may result in similar genetic structure. We evaluated these hypotheses jointly by quantifying the similarity of genetic structure in three South American marsh rat species (Holochilus), and test how genetic variation in each species relates to biome‐specific environmental space and historical stability.LocationSouth America.TaxonRodentia.MethodsUsing complementary analyses (Mantel tests, dbRDA, Procrustes, covariance structure of allele frequencies and environmental niche models [ENMs]) with 8,000–32,000 SNPs per species, we quantified the association between genomic variation and geographic and/or environmental differences.ResultsSignificant association between genetic variation and geography was identified for all species. Similarity in the strength of the association suggests connectivity patterns dictated by shared species‐traits predominate at the biome scale. However, substantial amounts of genetic variation are not explained by geography. Focusing on this portion of the variance, we demonstrate a significant quantitative association between genetic variation and the environmental space of a biome, and a qualitative association with varying regional stability. Specifically, historically stable areas estimated from ecological niche models are correlated with local levels of geographic structuring, suggesting that local biome‐specific histories affect population isolation/connectivity.Main conclusionsThese tests show that although species exhibit similar patterns of genetic variation that are consistent with shared natural histories, irrespective of inhabiting different wetland biomes, local biome‐specific properties (i.e. varying environmental conditions and historical stability) contribute to departures from equilibrium patterns of genetic variation expected by isolation by geographic distance. The reflection of these biome‐specific properties in the genetic structure of the marsh rats provides a window into the differences among South American wetlands with evolutionary consequences for their respective constituent assemblages.

Landscape Modeling of the Potential Natural Vegetation of Santa Catalina Island, California

The vegetation of Santa Catalina Island has been significantly transformed through a history of introduction of exotic plant species and disturbance by large introduced herbivores. Many of these disturbances have been reduced in recent decades, using measures such as carefully controlling the number of bison and removing cattle, sheep, feral pigs, and goats. The success of subsequent vegetation restoration actions depends on the choice of the right plant community for a location, which may not be obvious for an island with extensive areas dominated by exotic species. Environmental niche modeling is an approach to re-create the spatial distribution of habitat types for such a purpose. Such models, however, often require both presence and absence data to be meaningful, while in this scenario absence is misleading because it may reflect a long history of disturbance. Maximum entropy modeling is a technique to model species distributions with presence-only data that has been shown to produce accurate results. We used this modeling tool to model the environmental niche for distinct vegetation types, conceptualized as potential natural vegetation, on Catalina Island as a means to predict locations where restoration actions would be most successful and to predict potential natural vegetation prior to anthropogenic disturbance. Using an existing vegetation map, we extracted random points from within the polygons defining each native vegetation type. We then modeled the habitat suitability for each habitat using high-resolution environmental data that included elevation, aspect, hillshade, northeastness, slope, solar radiation, and topographic wetness index. The resulting models were combined to produce a map of potential natural vegetation. A 1977 map of potential natural vegetation included 4 vegetation types (woodland, chaparral, scrub, and grassland) to which we compared our results. Our new model of potential natural vegetation has high spatial complexity and high resolution. It also shows naturalistic responses to topography that are consistent with the broad patterns mapped in 1977 while providing fine-scale resolution to inform restoration efforts.

Knowledge to decision in dynamic seas: Methods to incorporate non-indigenous species into cumulative impact assessments for maritime spatial planning

Incorporating ecosystem changes from non-indigenous species (NIS) is an important task of maritime spatial planning. Maritime spatial planning requires a framework that emphasises ecological functioning in a state of dynamic change, including changes to ecosystem services from functions introduced by new NIS. Adaptable modelling toolsets should be developed that can readily incorporate knowledge of new NIS. In the Baltic Sea, recent NIS examples are the North American mud crab Rhithropanopeus harrisii and the Ponto-Caspian round goby Neogobius melanostomus. We performed environmental niche modelling that predicted N. melanostomus will spread across large areas of the Baltic Sea coast while R. harrisii will be limited to regions with high temperature and low salinity conditions. We then performed a meta-analysis on literature showing effects in the Baltic Sea from these NIS and calculated the standardised effect-sizes on relevant ecosystem services. Half the impacts identified for N. melanostomus were considered to increase ecosystem service outcomes, while all R. harrisii impacts caused apparent decreases. Effect coefficients were incorporated into an online impact assessment tool developed by the Estonian Marine Institute. Users with or without science training can use the portal to estimate areas impacted and changes to natural assets (km2) caused by these NIS and cumulative effects from other pressure-types. Impact estimates are based on best available knowledge from manipulative and correlative experiments and thus form a link between science and management. Dynamic modelling techniques informed from varied ecological and methodological perspectives will effectively advise spatial planners about rapid maritime changes and mitigation actions to reduce NIS impacts especially in the focus areas.

The importance of hidden diversity for insect conservation: a case study in hoverflies (the Merodon atratus complex, Syrphidae, Diptera)

Cryptic species represent a large component of hidden biodiversity. Some cryptic taxa require specific climate and habitat conditions and have limited dispersal abilities. In order to assess the importance of cryptic species and to minimize future loss of biodiversity, we modelled the current and future distribution of the Merodon atratus (Oldenberg, 1919) species complex, once thought to be a single species, and compared it with species distribution models for each of the three cryptic species within the complex (M. atratus, M. balkanicus Sasic, Acanski et Vujic, 2016, M. virgatus Vujic et Radenkovic, 2016). Additionally, we compared environmental niche models for each cryptic species. We then tested the capability of nationally designated protected areas to encompass the species complex and each cryptic species of the complex. We conclude that although cryptic species of the M. atratus complex exhibit high levels of morphological similarity, they will respond differently to global climate change, requiring tailored particular conservation strategies. Overall, the species complex will drastically decrease its range and retreat to the Alps. More specifically, each cryptic species requires specific environmental conditions and will react differently to climate change. These results contribute to the establishment of a conservation status for these newly discovered species and their conservation management, particularly for M. balkanicus that is projected to go extinct due to global warming.

Tracking Host Trees: The Phylogeography of EndemicPsittacanthus sonorae(Loranthaceae) Mistletoe in the Sonoran Desert

The host dependence of mistletoes suggests that they track the distributions of their hosts. However, the factors that determine the geographic distribution of mistletoes are not well understood. In this study, the phylogeography of Psittacanthus sonorae was reconstructed by sequencing one nuclear (ITS) and two plastid (trnL-F and atpB-rbcL) regions of 148 plants from populations separated by the Sea of Cortez. Divergence time and gene flow were estimated to gain insight into the historical demography and geographic structuring of genetic variation. We also described and mapped the spatial distribution of suitable habitat occupied by P. sonorae and its most common host Bursera microphylla in the Sonoran Desert, along with their responses to Quaternary climate fluctuations using environmental data and ecological niche modeling (ENM). We detected environmental and genetic differentiation between the peninsular and continental P. sonorae populations. Population divergence occurred during the Pleistocene, around the time of the Last Glacial Maximum. No signals of population growth were detected, with net gene flow moving from the continent to the peninsula. ENM models indicate decoupled responses by the mistletoe and its main host to past climate changes. For the Last Interglacial to the present, most models produce only partial areas of overlap on both the peninsula and the continent. Our results support a scenario of Late-Pleistocene isolation and divergence with asymmetrical gene flow between peninsular and continental P. sonorae populations. Continental populations migrated to the peninsula and the spatial isolation probably produced genetic differentiation under different environmental conditions.

Restore and Renew: a genomics‐era framework for species provenance delimitation

Here we present “Restore and Renew,” a replicable framework for gathering and interpreting evolutionary, ecological, and genomic data in support of restoration practices. In an era of rapid climatic change and continuous widespread clearing, revegetation projects need to focus on producing resilient and long‐term self‐sustaining populations. Restore and Renew expands current knowledge of genetic provenance via genome‐scan data, environmental niche modeling (ENM), and site‐specific climate information. The sampling strategy is to obtain leaf tissue representing the distributions of over 100 species commonly used in restoration. We apply generalized dissimilarity modeling to genome‐wide single nucleotide polymorphism datasets from hundreds of samples. Species‐specific local provenances are obtained using a model that represents observed patterns of genetic variation across the landscape. Climate modeling is implemented to interpret genetic provenance boundaries in the context of current and future climatic conditions at the specified site. Results are presented in an easy‐to‐use webtool (www.restore‐and‐renew.org.au), where the user simply selects their site of interest and a target species to obtain the size and distribution of local genetic provenance. Although Restore and Renew is not prescriptive, it allows restoration practitioners to make informed decisions on where to source material from, to fulfill their restoration scenario of choice. Two examples,Westringia fruticosaandAcacia suaveolens, are presented to demonstrate how the analytical pipeline responds to different ecological and evolutionary patterns. The webtool has multiple applications for biodiversity management and will continue to evolve with new species and analytical/interpretative outputs.

The role of competition in driving species global distributions: Soricid shrews as a case study

AbstractAimWe aim to determine the relative influence of climate and species interactions on the global distribution of Soricinae and Crocidurinae shrews through the analysis of their distribution, climate niche and evolutionary history. Both subfamilies are partially allopatric in Eurasia, but in North America only Soricinae is present, thus providing a scenario to address the role of potential competition versus competitive release in determining species’ realized distributions at a global scale.LocationGlobal.TaxonSoricidae, Eulipotyphla.MethodsWe obtained climate data from WorldClim, spatial range data for 302 species from the IUCN Red List and 2614 cytb complete sequences from GenBank. We modelled the potential distribution of the subfamilies by computing three environmental niche models using Maxent: one for Crocidurinae, one for American Soricinae and one for Afro‐Eurasian Soricinae. We created matrices for the genetic, spatial and climatic distance between all pairs of species to calculate the average climatic distance between pairs of species within and between subfamilies. We then evaluated this distance against a null model. To assess the effect of phylogeny on the segregation of the subfamilies, we checked for correlation between genetic and spatial distance.ResultsThe Afro‐Eurasian Soricinae environmental niche model under‐predicted its occurrence in America. The average climatic distance between subfamilies was larger than expected by chance, while the distance within both Crocidurinae and Afro‐Eurasian Soricinae was smaller. The average distance between the American and Afro‐Eurasian Soricinae was also larger than expected. There was no correlation between spatial and genetic distance for genetic distances over 0.14 substitutions per nucleotide site.Main conclusionsClimate significantly influences the distribution of both subfamilies. As expected in a scenario of competitive release, the climatic range of the Soricinae in America is larger than in Afro‐Eurasia. Thus, besides climate, competition may play an important role in shaping species’ global distributions.

Climate change may have minor impact on zooplankton functional diversity in the Mediterranean Sea

AbstractAimTo assess the impact of climate change on the functional diversity of marine zooplankton communities.LocationThe Mediterranean Sea.MethodsWe used the functional traits and geographic distributions of 106 copepod species to estimate the zooplankton functional diversity of Mediterranean surface assemblages for the 1965–1994 and 2069–2098 periods. Multiple environmental niche models were trained at the global scale to project the species habitat suitability in the Mediterranean Sea and assess their sensitivity to climate change predicted by several scenarios. Simultaneously, the species traits were used to compute a functional dendrogram from which we identified seven functional groups and estimated functional diversity through Faith's index. We compared the measured functional diversity to the one originated from null models to test if changes in functional diversity were solely driven by changes in species richness.ResultsAll but three of the 106 species presented range contractions of varying intensity. A relatively low decrease of species richness (−7.42 on average) is predicted for 97% of the basin, with higher losses in the eastern regions. Relative sensitivity to climate change is not clustered in functional space and does not significantly vary across the seven copepod functional groups defined. Changes in functional diversity follow the same pattern and are not different from those that can be expected from changes in richness alone.Main conclusionsClimate change is not expected to alter copepod functional traits distribution in the Mediterranean Sea, as the most and the least sensitive species are functionally redundant. Such redundancy should buffer the loss of ecosystem functions in Mediterranean zooplankton assemblages induced by climate change. Because the most negatively impacted species are affiliated to temperate regimes and share Atlantic biogeographic origins, our results are in line with the hypothesis of increasingly more tropical Mediterranean communities.

Assessing protected area effectiveness within the Caribbean under changing climate conditions: A case study of the small island, Trinidad

Habitat loss and more recently, climate change are primary challenges to the effectiveness of protected area networks (PANs) in species conservation within many archipelagic biodiversity hotspots across the globe. An environmental niche model (ENM) of 11 high-conservation-value tree species was used to assess the effectiveness of the PAN within the Caribbean island of Trinidad under future (2050s) climate conditions. Overlay analyses were conducted inside and outside of existing PANs to determine the proportions of natural and plantation (monoculture) forests. Proportions of this species group’s climate space projected to be critical for conservation (combination of stable and expanding zones or ‘Z4’) that are under forest cover were also calculated. Approximately 63% of Trinidad is forested, with the majority of plantation forests located within the PAN, producing noticeable areas of cleared forest when harvested. The ENM projected a drastic reduction in climate space for this group of high-conservation-value tree species across the island. However, approximately 54% of the Z4 space was projected to occur within the PAN; and 61% of the Z4 falling outside the PAN was under forest cover. Consequently, conservation of this species group could be greatly enhanced by increasing the proportion of its Z4 climate space outside the PAN under maintained forest/secondary vegetation cover. Given the small size of small island states (SIS) (such as those in the Caribbean) relative to the macro-scale of climate change, a more effective means of managing climate-induced species loss could involve the development of regional-scale PANs rather than separate efforts of individual SIS.

Niche squeeze induced by climate change of the cold-tolerant subtropical montane Podocarpus parlatorei.

Under changing climates, the persistence of montane subtropical taxa may be threatened as suitable habitats decrease with elevation. We developed future environmental niche models (ENNMs) for Podocarpus parlatorei, the only conifer from southern Yungas in South America, and projected it onto two greenhouse gas concentration scenarios based on 13 global climate models for the years 2050 and 2070. Modelling identified that P. parlatorei is sensitive and restricted to a relatively narrow range of both warm season temperature and precipitation. By the mid-late twenty-first century areas of high suitability for P. parlatorei will not migrate but overall suitability will become substantially reduced across its whole range and surrounding areas. Despite extensive areas in high mountain ranges where the species may encounter thermally optimal conditions to potentially allow upward local migration, these same areas will likely become strongly aridified under future conditions. On the other hand, in lowland locations where rainfall levels will not change substantially (e.g. northern range), excessive warming will likely generate abiotic and biotic restrictions (e.g. competition with lowland species) for this cold-tolerant species. Urgent measures should be developed for the local long-term preservation of the gene pool of the unique conifer that characterizes Yungas forests for reasons of biodiversity conservation and ecosystem services.

Behavioural thermoregulation and climatic range restriction in the globally threatened Ethiopian Bush‐crow Zavattariornis stresemanni

Climate may influence the distribution and abundance of a species through a number of demographic and ecological processes, but the proximate drivers of such responses are only recently being identified. The Ethiopian Bush‐crow Zavattariornis stresemanni is a starling‐like corvid that is restricted to a small region of southern Ethiopia. It is classified as Endangered in the IUCN Red List of globally threatened species. Previous work suggested that this range restriction is almost perfectly defined by a climate envelope that is cooler than surrounding areas, but the proximate mechanism remains unexplained. The heavily altered habitats which the species inhabits are widespread across Africa, and recent work has shown that the Bush‐crow is behaviourally adaptable and has a catholic diet. We assess whether its enigmatic distribution can be explained by behavioural responses to the higher temperatures that surround its current range. Using environmental niche models and field observations of thermally mediated behaviour, we compare the range restriction and behavioural thermoregulation of the Ethiopian Bush‐crow with those of two sympatric control species that are similar in size and ecology, but have much larger ranges that include hotter environments. White‐crowned Starling Lamprotornis albicapillus and Superb Starling L. superbus occupy similar habitats to the Ethiopian Bush‐crow and all three frequently forage together. We found that the Bush‐crow's range is limited primarily by temperature, with a secondary effect of dry season rainfall, whereas the ranges of the two starling species are better predicted by wet season rainfall alone. Bush‐crows exhibited panting behaviour and moved into the shade of trees at significantly lower ambient temperatures than did the starlings, and their food intake declined more steeply with increasing temperature. These results indicate that the limited geographical range of the Bush‐crow reflects an inability to cope with higher temperatures. This suggests that a species' response to climate change might not be easily predicted by its ecological generalism, and may represent an inherited debt from its evolutionary history.