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1.
Thomas Evans Sabrina Kumschick Çağan H. Şekercioğlu Tim M. Blackburn 《Diversity & distributions》2018,24(6):800-810
Aim
To identify traits related to the severity and type of environmental impacts generated by alien bird species, in order to improve our ability to predict which species may have the most damaging impacts.Location
Global.Methods
Information on traits hypothesized to influence the severity and type of alien bird impacts was collated for 113 bird species. These data were analysed using mixed effects models accounting for phylogenetic non‐independence of species.Results
The severity and type of impacts generated by alien bird species are not randomly distributed with respect to their traits. Alien range size and habitat breadth were strongly associated with impact severity. Predation impacts were strongly associated with dietary preference, but also with alien range size, relative brain size and residence time. Impacts mediated by interactions with other alien species were related to alien range size and diet breadth.Main conclusions
Widely distributed generalist alien birds have the most severe environmental impacts. This may be because these species have greater opportunity to cause environmental impacts through their sheer number and ubiquity, but this could also be because they are more likely to be identified and studied. Our study found little evidence for an effect of per capita impact on impact severity.2.
Aim
To assess how environmental, biotic and anthropogenic factors shape native–alien plant species richness relationships across a heterogeneous landscape.Location
Banks Peninsula, New Zealand.Methods
We integrated a comprehensive floristic survey of over 1200 systematically located 6 × 6 m plots, with corresponding climate, environmental and anthropogenic data. General linear models examined variation in native and alien plant species richness across the entire landscape, between native‐ and alien‐dominated plots, and within separate elevational bands.Results
Across all plots, there was a significant negative correlation between native and alien species richness, but this relationship differed within subsets of the data: the correlation was positive in alien‐dominated plots but negative in native‐dominated plots. Within separate elevational bands, native and alien species richness were positively correlated at lower elevations, but negatively correlated at higher elevations. Alien species richness tended to be high across the elevation gradient but peaked in warmer, mid‐ to low‐elevation sites, while native species richness increased linearly with elevation. The negative relationship between native and alien species richness in native‐dominated communities reflected a land‐use gradient with low native and high alien richness in more heavily modified native‐dominated vegetation. In contrast, native and alien richness were positively correlated in very heavily modified alien‐dominated plots, most likely due to covariation along a gradient of management intensity.Main conclusions
Both positive and negative native–alien richness relationships can occur across the same landscape, depending on the plant community and the underlying human and environmental gradients examined. Human habitat modification, which is often confounded with environmental variation, can result in high alien and low native species richness in areas still dominated by native species. In the most heavily human modified areas, dominated by alien species, both native and alien species may be responding to similar underlying gradients.3.
It takes one to know one: Similarity to resident alien species increases establishment success of new invaders
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Christine S. Sheppard Marta Carboni Franz Essl Hanno Seebens DivGrass Consortium Wilfried Thuiller 《Diversity & distributions》2018,24(5):680-691
Aim
Darwin's naturalization hypothesis states that dissimilarity to native species may benefit alien species establishment due to empty niches and reduced competition. We here add a new dimension to large‐scale tests of community invasibility, investigating the role that previously established alien species play in facilitating or hindering new invasions in plant communities.Location
Permanent grasslands across France (including mainland and Corsica), as a receding ecosystem of great conservation importance.Methods
Focusing on 121 alien plant species occurring in 7,215 vegetation plots, we quantified biotic similarity between new invaders and resident alien species (i.e., alien species with longer residence times) based on phylogenetic and trait distances. Additionally, we calculated distances to native species for each alien species and plot. Using multispecies distribution models, we analysed the influence of these biotic similarity measures and additional covariates on establishment success (presence/absence) of new invaders.Results
We found that biotic similarity to resident alien species consistently increased establishment success of more recently introduced species. Phylogenetic relatedness to previous invaders had an equally strong positive effect as relatedness to native species. Conversely, trait similarity to natives hindered alien establishment as predicted by Darwin's naturalization hypothesis. These results highlight that various mechanisms may act simultaneously to determine alien establishment success.Main conclusions
Our results suggest that, with greater similarity among alien species, invasion success increases. Such a pattern may arise either due to actual facilitation among invaders or as a result of weaker competitive interactions among invaders than between native and alien species, leading to an indirect facilitative effect. Alternatively, recent environmental changes (e.g., eutrophication, climate change) may have added new environmental filters. Determining how initial invasions might pave the road for subsequent invasions is crucial for effective multispecies management decisions and contributes a new aspect to our understanding of community assembly.4.
Invasion lags: The stories we tell ourselves and our inability to infer process from pattern
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Aim
Many alien species experience a lag phase between arriving in a region and becoming invasive, which can provide a valuable window of opportunity for management. Our ability to predict which species are experiencing lags has major implications for management decisions that are worth billions of dollars and that may determine the survival of some native species. To date, timing and causes of lag and release have been identified post hoc, based on historical narratives.Location
Global.Methods
We use a simple but realistic simulation of population spread over a fragmented landscape. To break the invasion lag, we introduce a sudden, discrete change in dispersal.Results
We show that the ability to predict invasion lags is minimal even under controlled circumstances. We also show a non‐negligible risk of falsely attributing lag breaks to mechanisms based on invasion trajectories and coincidences in timing.Main conclusions
We suggest that post hoc narratives may lead us to erroneously believe we can predict lags and that a precautionary approach is the only sound management practice for most alien species.5.
Species’ thermal ranges predict changes in reef fish community structure during 8 years of extreme temperature variation
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Paul B. Day Rick D. Stuart‐Smith Graham J. Edgar Amanda E. Bates 《Diversity & distributions》2018,24(8):1036-1046
Aim
To assess whether observed thermal bounds in species’ latitudinal ranges (i.e., realized thermal niches) can be used to predict patterns of occurrence and abundance changes observed during a marine heatwave, relative to other important life history and functional traits.Location
Rottnest Island, Western Australia.Methods
A time series of standardized quantitative surveys of reef fishes spanning 8 years of pronounced ocean temperature change is used to test whether accurate predictions on shifts in species occupancy and abundance are possible using species traits.Results
Species‐level responses in occurrence and abundance were closely related to the mid‐point of their realized thermal niche, more so than body size, range size or trophic level. Most of the species that disappeared from survey counts during the heatwave were characterized by geographic ranges that did not extend to latitudes with temperatures equivalent to the ocean temperature peak during the heatwave. We thus find support for the hypothesis that current distribution limits are set directly or indirectly by temperature and are highly responsive to ocean temperature variability.Main conclusions
Our study shows that reef fish community structure can change very quickly when exposed to extreme thermal anomalies, in directions predicted from the realized thermal niche of the species present. Such predictions can thus identify species that will be most responsive to changing ocean climate. Continued warming, coupled with periodic extreme heat events, may lead to the loss of ecosystem services and ecological functions, as mobile species relocate to more hospitable climes, while less mobile species may head towards extinction.6.
Projecting potential future shifts in species composition of European urban plant communities
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Zdeňka Lososová Lubomír Tichý Jan Divíšek Natálie Čeplová Jiří Danihelka Pavel Dřevojan Karel Fajmon Veronika Kalníková Veronika Kalusová Pavel Novák Vladimír Řehořek Tamás Wirth Milan Chytrý 《Diversity & distributions》2018,24(6):765-775
Aim
Urban floras are composed of species of different origin, both native and alien, and with various traits and niches. It is likely that these species will respond to the ongoing climate change in different ways, resulting in future species compositions with no analogues in current European cities. Our goal was to estimate potential shifts in plant species composition in European cities under different scenarios of climate change for the 21st century.Location
Europe.Methods
Potential changes in the distribution of 375 species currently growing in 60 large cities in Southern, Central and Western Europe were modelled using generalized linear models and four climate change projections for two future periods (2041–2060 and 2061–2080). These projections were based on two global climate models (CCSM4 and MIROC‐ESM) and two Representative Concentration Pathways (2.6 and 8.5).Results
Results were similar across all climate projections, suggesting that the composition of urban plant communities will change considerably due to future climate change. However, even under the most severe climate change scenario, native and alien species will respond to climate change similarly. Many currently established species will decline and others, especially annuals currently restricted to Southern Europe, will spread to northern cities. In contrast, perennial herbs, woody plants and most species with temperate continental and oceanic distribution ranges will make up a smaller proportion of future European urban plant communities in comparison with the present communities.Main conclusions
The projected 21st century climate change will lead to considerable changes in the species composition of urban floras. These changes will affect the structure and functioning of urban plant communities.7.
Species traits suggest European mammals facing the greatest climate change are also least able to colonize new locations
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Aim
The risk climate change poses to biodiversity is often estimated by forecasting the areas that will be climatically suitable for species in the future and measuring the distance of the “range shifts” species would have to make to reach these areas. Species’ traits could indicate their capacity to undergo range shifts. However, it is not clear how range‐shift capacity influences risk. We used traits from a recent evidence review to measure the relative potential of species to track changing climatic conditions.Location
Europe.Time period
Baseline period (1961–1990) and forecast period (2035–2064).Major taxa studied
62 mammal species.Methods
We modelled species distributions using two general circulation models and two representative concentration pathways (RCPs) to calculate three metrics of “exposure” to climate change: range area gained, range area lost and distance moved by the range margin. We identified traits that could inform species’ range‐shift capacity (i.e., potential to establish new populations and proliferate, and thus undertake range shifts), from a recent evidence‐based framework. The traits represent ecological generalization and reproductive strategy. We ranked species according to each metric of exposure and range‐shift capacity, calculating sensitivity to ranking methods, and synthesized both exposure and range‐shift capacity into “risk syndromes.”Results
Many species studied whose survival depends on colonizing new areas were relatively unlikely to undergo range shifts. Under the worst‐case scenario, 62% of species studied were relatively highly exposed. 47% were highly exposed and had relatively low range‐shift capacity. Only 14% of species faced both low exposure and high range‐shift capacity. Both range‐shift and exposure metrics had a greater effect on risk assessments than climate models.Main conclusions
The degree to which species’ potential ranges will be altered by climate change often does not correspond to species’ range‐shift capacities. Both exposure and range‐shift capacity should be considered when evaluating biodiversity risk from climate change.8.
Aim
Spring wetlands in arid regions of Australia provide habitat for many highly endemic organisms, including fish, molluscs, crustaceans and plants, but these unique ecosystems have been under pressure since the arrival of Europeans about 250 years ago. Arguments over whether particular plant species are long‐term spring inhabitants or recent immigrants are confounding efforts to conserve spring flora. One such example is the swamp foxtail, Cenchrus purpurascens, a grass that is variably listed in the literature as being native to Australian wetlands or as being an introduced weedy species from Asia.Location
Australia, China and Korea.Methods
We use DNA sequences of the nuclear ITS and the chloroplast DNA regions trnL‐F and matK, complemented with newly designed simple sequence repeat (SSR) markers, to assess the native status of C. purpurascens in Australia and determine whether there is genetic differentiation among spring populations.Results
We find that, although there has been gene flow between Asia and Australia in the geological past, the populations are now strongly differentiated: C. purpurascens has probably been present in Australia through the Pleistocene. In Australia, there is also strong genetic differentiation among populations from different springs, and between springs and non‐springs populations, indicating long‐term occupancy of some springs sites.Main conclusions
Cenchrus purpurascens was present in Australia well before European colonization of the continent. The level of genetic differentiation among populations enhances the existing conservation values of Elizabeth Springs, Edgbaston, Doongmabulla and Carnarvon Gorge springs complexes within the Great Artesian Basin.9.
Seventy years of stream‐fish collections reveal invasions and native range contractions in an Appalachian (USA) watershed
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Joseph D. Buckwalter Emmanuel A. Frimpong Paul L. Angermeier Jacob N. Barney 《Diversity & distributions》2018,24(2):219-232
Aim
Knowledge of expanding and contracting ranges is critical for monitoring invasions and assessing conservation status, yet reliable data on distributional trends are lacking for most freshwater species. We developed a quantitative technique to detect the sign (expansion or contraction) and functional form of range‐size changes for freshwater species based on collections data, while accounting for possible biases due to variable collection effort. We applied this technique to quantify stream‐fish range expansions and contractions in a highly invaded river system.Location
Upper and middle New River (UMNR) basin, Appalachian Mountains, USA.Methods
We compiled a 77‐year stream‐fish collections dataset partitioned into ten time periods. To account for variable collection effort among time periods, we aggregated the collections into 100 watersheds and expressed a species’ range size as detections per watershed (HUC) sampled (DPHS). We regressed DPHS against time by species and used an information‐theoretic approach to compare linear and nonlinear functional forms fitted to the data points and to classify each species as spreader, stable or decliner.Results
We analysed changes in range size for 74 UMNR fishes, including 35 native and 39 established introduced species. We classified the majority (51%) of introduced species as spreaders, compared to 31% of natives. An exponential functional form fits best for 84% of spreaders. Three natives were among the most rapid spreaders. All four decliners were New River natives.Main conclusions
Our DPHS‐based approach facilitated quantitative analyses of distributional trends for stream fishes based on collections data. Partitioning the dataset into multiple time periods allowed us to distinguish long‐term trends from population fluctuations and to examine nonlinear forms of spread. Our framework sets the stage for further study of drivers of stream‐fish invasions and declines in the UMNR and is widely transferable to other freshwater taxa and geographic regions.10.
Biogeographical patterns of endemic diversity and its conservation in Australia's artesian desert springs
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R. A. Rossini R. J. Fensham B. Stewart‐Koster T. Gotch M. J. Kennard 《Diversity & distributions》2018,24(9):1199-1216
Aim
Springs in the Australian arid zone are distinct from other waterways because they house a large number of endemic species. We aimed to assess spatial patterns in endemic diversity at a basin‐wide scale and whether environmental features can help to explain them. In doing so, we take the opportunity to summarize the current state of conservation in the system.Location
Great Artesian Basin (GAB), arid and semiarid regions of eastern AustraliaMethods
We combine data regarding the location of springs with published GIS layers regarding environmental characteristics and a literature review of all species and subspecies documented in the published literature to be endemic to GAB springs.Results
We found evidence of 96 species and subspecies of fishes, molluscs, crustaceans and plants endemic to these springs. The majority of endemic species are invertebrates with geographical distributions limited to a single spring complex (<61 km2). Endemic taxa are concentrated in 75 of the 326 spring complexes. Spring complexes with a large number of springs, high connectivity via drainage basins and low rainfall were more likely to contain endemic taxa, but environmental models were poor predictors of diversity. Only 24% spring complexes with high conservation value are within conservation reserves, and the majority of endemic species are unassessed under the IUCN and Australian conservation legislation, particularly the invertebrates.Main conclusions
Diversity in this system is underestimated given the current rate of species discovery and prevailing data deficiency for many taxa. Historical processes and species‐specific environmental requirements may be more important for explaining why diversity is concentrated in particular complexes. Almost a decade after this system was listed as endangered, most complexes of high conservation value remain outside of conservation reserves, and the endangered species status of many taxa, and particularly the invertebrates, remain unassessed.11.
Fishing pressure and species traits affect stream fish invasions both directly and indirectly
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Aim
We sought to identify direct and indirect effects of factors contributing to establishment and spread of 272 stream fish species.Location
Two hundred and ninety‐seven watersheds in the eastern United States.Methods
We modelled two variables: (1) whether a species had become established outside its native range (establishment) and (2) the number of watersheds in which species established outside their native range (spread). We estimated these variables by comparing historical distributions to a rich data set of contemporary sampling. We calculated metrics of human use (indexing propagule pressure), and gathered species trait data from an open‐access database. We then used piecewise path analysis to estimate direct and indirect effects of human use, native range size and species traits on the two metrics of species introductions.Results
We identified a hierarchical causal structure in which native range size and fishing pressure were important direct determinants of introductions. Species traits had some direct effects, but played a more indirect role. Native range size was significantly affected by thermal tolerance and diet breadth. Likewise, fishing pressure was significantly affected by life history strategy: larger‐bodied, longer‐living and more fecund species were positively associated with fishing pressure.Main conclusions
Functional traits can confer an advantage to some species during the establishment phase, but human use is important for subsequent dispersal throughout the non‐native range. However, human use is non‐random, and is largely a function of species traits. Considering both direct and indirect effects of traits across stages of the invasion process can help to elucidate the full role of traits in species invasions.12.
Aim
With the exception of South Africa there are no systematic, long‐term, large‐scale bird monitoring programmes in Africa, and for much of the continent the most comprehensive available data for most species are incidental occurrence records. Can such data be used to assess range‐wide conservation status of widespread low‐density species? We examine this using Kori Bustard Ardeotis kori, a large, easily identifiable species with an extensive African range.Location
Southern and East Africa, 14 countries.Methods
A comprehensive and systematic review of published and unpublished sources provided 1948 unique locality records spanning the years 1863–2009; these included 410 non‐atlas records and 97 historical (pre‐1970) records. Range‐size changes were examined by comparing minimum convex polygons to quantify Extent of Occurrence pre‐ and post‐1970, and by testing whether more historical records fell outside the recent (post‐1970) 95% probability kernel than expected by chance. Additionally, qualitative evidence of changes in abundance was obtained from historical published accounts and contemporary assessments by in‐country experts.Results
Since the late 19th century, range‐size (measured as Extent of Occurrence) has contracted, by 21% in East Africa and 8% in southern Africa. There is strong qualitative evidence of considerable pre‐ and post‐1970 population declines in all range states, except Zambia (slight increase) and Angola (trend unclear). In some countries, declines occurred from the early 1900s. Thus, while relatively modest change in range‐size has occurred in over 100 years, numbers have greatly reduced throughout the species’ range.Main conclusions
Our methodology allowed objective appraisal of continent‐wide Kori status. Despite lacking quantitative population estimates and trends, and poor understanding of the species’ autecology, common issues for many African species, incidental occurrence records can be used to assess range‐wide changes in status. We recommend that this or similar approaches be applied to other widespread low‐density species that probably also have rapidly declining populations despite apparently stable range extents.13.
J. Judson Wynne Stefan Sommer Francis G. Howarth Brett G. Dickson Kyle D. Voyles 《Diversity & distributions》2018,24(10):1478-1491
Aim
Identify the optimal combination of sampling techniques to maximize the detection of diversity of cave‐dwelling arthropods.Location
Central‐western New Mexico; north‐western Arizona; Rapa Nui, Chile.Methods
From 26 caves across three geographically distinct areas in the Western Hemisphere, arthropods were sampled using opportunistic collecting, timed searches, and baited pitfall trapping in all caves, and direct intuitive searches and bait sampling at select caves. To elucidate the techniques or combination of techniques for maximizing sampling completeness and efficiency, we examined our sampling results using nonmetric multidimensional scaling (NMDS), analysis of similarity (ANOSIM), Wilcoxon signed‐rank tests, species richness estimators and species accumulation curves.Results
To maximize the detection of cave‐dwelling arthropod species, one must apply multiple sampling techniques and specifically sample unique microhabitats. For example, by sampling cave deep zones and nutrient resource sites, we identified several undescribed cave‐adapted and/or cave‐restricted taxa in the south‐western United States and eight new species of presumed cave‐restricted arthropods on Rapa Nui that would otherwise have been missed. Sampling techniques differed in their detection of both management concern species (e.g., newly discovered cave‐adapted/restricted species, range expansions of cave‐restricted species and newly confirmed alien species) and specific taxonomic groups. Spiders were detected primarily with visual search techniques (direct intuitive searches, opportunistic collecting and timed searches), while most beetles were detected using pitfall traps. Each sampling technique uniquely identified species of management concern further strengthening the importance of a multi‐technique sampling approach.Main conclusions
Multiple sampling techniques were required to best characterize cave arthropod diversity. For techniques applied uniformly across all caves, each technique uniquely detected between ~40% and 67% of the total species observed. Also, sampling cave deep zones and nutrient resource sites was critical for both increasing the number of species detected and maximizing the likelihood of detecting management concern species.14.
Katharina Dehnen‐Schmutz Thomas Boivin Franz Essl Quentin J. Groom Laura Harrison Julia M. Touza Helen Bayliss 《Diversity & distributions》2018,24(8):1149-1157
Aim
To collect and identify the issues that may affect the future global and local management of biological invasions in the next 20–50 years and provide guidance for the prioritization of actions and policies responding to the management challenges of the future.Location
GlobalMethods
We used an open online survey to poll specialists and stakeholders from around the world as to their opinion on the three most important future issues both globally and at their respective local working level.Results
The 240 respondents identified 629 global issues that we categorized into topics. We summarized the highest rated topics into five broad thematic areas: (1) environmental change, particularly climate change, (2) the spread of species through trade, (3) public awareness, (4) the development of new technologies to enhance management and (5) the need to strengthen policies. The respondents also identified 596 issues at their respective local working levels. Management, early detection, prevention and funding‐related issues all ranked higher than at the global level. Our global audience of practitioners, policymakers and researchers also elicited topics not identified in horizon scanning exercises led by scientists including potential human health impacts, the need for better risk assessments and legislation, the role of human migration and water management.Main conclusions
The topic areas identified in this horizon scan provide guidance where future policy priorities for invasive alien species should be set. First, to reduce the magnitude and speed of environmental change and its impacts on biological invasions; second, to restrict the movement of potentially invasive alien species via trade; third, to raise awareness with the general public and empower them to act; and finally, to invest in innovative technologies that can detect and mitigate adverse impacts of introduced species.15.
Standardized genetic diversity‐life history correlates for improved genetic resource management of Neotropical trees
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Andrew J. Lowe Henri Caron Nathalie Colpaert Christopher Dick Bryan Finegan Mike Gardner Godelieve Gheysen Rogério Gribel J. Berton C. Harris Antoine Kremer Maristerra R. Lemes Rogerio Margis Carlos M. Navarro Fabiano Salgueiro Heidy M. Villalobos‐Barrantes Stephen Cavers 《Diversity & distributions》2018,24(6):730-741
Aim
Life history traits and range size are key correlates of genetic diversity in trees. We used a standardized sampling protocol to explore how life history traits and range size relate to the magnitude, variance and structuring (both between‐ and within‐population) of genetic diversity in Neotropical tree species.Location
The NeotropicsMethods
We present a meta‐analysis of new population genetic data generated for 23 Neotropical tree species (=2,966 trees, 86 populations) across a shared and broad geographic area. We compared established population genetic metrics across these species (e.g., genetic diversity, population structure, fine‐scale genetic structure), plus we estimated the rarely used variance in genetic diversity among populations. We used a multivariate, maximum likelihood, multimodel inference approach to explore the relative influence of life history traits and range size on patterns of neutral genetic diversity.Results
We found that pioneer and narrow range species had lower levels but greater variance in genetic diversity—signs of founder effects and stronger genetic drift. Animal‐dispersed species had lower population differentiation, indicating extensive gene flow. Abiotically dispersed and pioneer species had stronger fine‐scale genetic structure, suggesting restricted seed dispersal and family cohort establishment.Main conclusions
Our multivariable and multispecies approach allows ecologically relevant conclusions, since knowing whether one parameter has an effect, or one species shows a response in isolation, is dependent on the combination of traits expressed by a species. Our study demonstrates the influence of ecological processes on the distribution of genetic variation in tropical trees, and will help guide genetic resource management, and contribute to predicting the impacts of land use change.16.
Matthew G. Betts Ben Phalan Sarah J. K. Frey Josée S. Rousseau Zhiqiang Yang 《Diversity & distributions》2018,24(4):439-447
Aim
Habitat loss and climate change constitute two of the greatest threats to biodiversity worldwide, and theory predicts that these factors may act synergistically to affect population trajectories. Recent evidence indicates that structurally complex old‐growth forest can be cooler than other forest types during spring and summer months, thereby offering potential to buffer populations from negative effects of warming. Old growth may also have higher food and nest‐site availability for certain species, which could have disproportionate fitness benefits as species approach their thermal limits.Location
Pacific Northwestern United States.Methods
We predicted that negative effects of climate change on 30‐year population trends of old‐growth‐associated birds should be dampened in landscapes with high proportions of old‐growth forest. We modelled population trends from Breeding Bird Survey data for 13 species as a function of temperature change and proportion old‐growth forest.Results
We found a significant negative effect of summer warming on only two species. However, in both of these species, this relationship between warming and population decline was not only reduced but reversed, in old‐growth‐dominated landscapes. Across all 13 species, evidence for a buffering effect of old‐growth forest increased with the degree to which species were negatively influenced by summer warming.Main conclusions
These findings suggest that old‐growth forests may buffer the negative effects of climate change for those species that are most sensitive to temperature increases. Our study highlights a mechanism whereby management strategies to curb degradation and loss of old‐growth forests—in addition to protecting habitat—could enhance biodiversity persistence in the face of climate warming.17.
Moving from representation to persistence: The capacity of Australia's National Reserve System to support viable populations of mammals
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Aim
Species require sufficiently large and connected areas of suitable habitat to support populations that can persist through change. With extensive alteration of unprotected natural habitat, there is increasing risk that protected areas (PAs) will be too small and isolated to support viable populations in the long term. Consequently, this study addresses the urgent need to assess the capacity of PA estates to facilitate species persistence.Location
Australia.Methods
We undertake the first assessment of the capacity of the Australian National Reserve System (NRS) to protect 90 mammal species in the long term, given the size and distribution of individual PAs across the landscape relative to species’ habitat and minimum viable area (MVA) requirements and dispersal capabilities.Results
While all mammal ranges are represented within the NRS, the conservation capacity declined notably when we refined measures of representation within PAs to include species’ habitat and area requirements. The NRS could not support any viable populations for between three and seven species, depending on the MVA threshold used, and could support less than 10 viable populations for up to a third of the species. Planning and managing PAs for persistence emerged as most important for species with large MVA requirements and limited dispersal capabilities.Main conclusions
The key species characteristics we identify can help managers recognize species at risk within the current PA estate and guide the types of strategies that would best reduce this risk. We reveal that current representation‐based assessments of PA progress are likely to overestimate the long‐term success of PA estates, obscuring vulnerabilities for many species. It is important that conservation planners and managers are realistic and explicit regarding the role played by different sizes and distributions of PAs, and careful in assuming that the representation of a species within a PA equates to its long‐term conservation.18.
Land use legacy effects on woody vegetation in agricultural landscapes of south‐western Ethiopia
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Girma Shumi Jannik Schultner Ine Dorresteijn Patrícia Rodrigues Jan Hanspach Kristoffer Hylander Feyera Senbeta Joern Fischer 《Diversity & distributions》2018,24(8):1136-1148
Aim
Past land use legacy effects—extinction debts and immigration credits—might be particularly pronounced in regions characterized by complex and dynamic landscape change. The aim of this study was to evaluate how current woody plant species distribution, composition and richness related to historical and present land uses.Location
A smallholder farming landscape in south‐western Ethiopia.Methods
We surveyed woody plants in 72 randomly selected 1‐ha sites in farmland and grouped them into forest specialist, generalist and pioneer species. First, we investigated woody plant composition and distribution using non‐metric multidimensional scaling. Second, we modelled species richness in response to historical and current distance from the forest edge. Third, we examined diameter class distributions of trees in recently converted vs. permanent farmland.Results
Historical distance was a primary driver of woody plant composition and distribution. Generalist and pioneer species richness increased with historical distance. Forest specialists, however, did not respond to historical distance. Only few old individuals of forest specialist species remained in both recently converted and permanent farmlands.Main conclusions
Our findings suggest that any possible extinction debt for forest specialist species in farmland at the landscape scale was rapidly paid off, possibly because farmers cleared large remnant trees. In contrast, we found substantial evidence of immigration credits in farmland for generalist and pioneer species. This suggests that long‐established farmland may have unrecognized conservation values, although apparently not for forest specialist species. We suggest that conservation policies in south‐western Ethiopia should recognize not only forests, but also the complementary value of the agricultural mosaic—similar to the case of European cultural landscapes. A possible future priority could be to better reintegrate forest species in the farmland mosaic.19.
Phylogenetic dimension of tree communities reveals high conservation value of disturbed tropical rain forests
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Edgar E. Santo‐Silva Bráulio A. Santos Víctor Arroyo‐Rodríguez Felipe P. L. Melo Deborah Faria Eliana Cazetta Eduardo Mariano‐Neto Manuel A. Hernández‐Ruedas Marcelo Tabarelli 《Diversity & distributions》2018,24(6):776-790
Aim
The conversion of old‐growth tropical forests into human‐modified landscapes threatens biodiversity worldwide, but its impact on the phylogenetic dimension of remaining communities is still poorly known. Negative and neutral responses of tree phylogenetic diversity to land use change have been reported at local and landscape scales. Here, we hypothesized that such variable responses to disturbance depend on the regional context, being stronger in more degraded rain forest regions with a longer history of land use.Location
Six regions in Mexico and Brazil.Methods
We used a large vegetation database (6,923 trees from 686 species) recorded in 98 50‐ha landscapes distributed across two Brazilian and four Mexican regions, which exhibit different degrees of disturbance. In each region, we assessed whether phylogenetic alpha and beta diversities were related to landscape‐scale forest loss, the percentage of shade‐intolerant species (a proxy of local disturbance) and/or the relatedness of decreasing (losers) and increasing (winners) taxa.Results
Contrary to our expectations, the percentage of forest cover and shade‐intolerant species were weakly related to phylogenetic alpha and beta diversities in all but one region. Loser species were generally as dispersed across the phylogeny as winner species, allowing more degraded, deforested and species‐poorer forests to sustain relatively high levels of evolutionary (phylogenetic) diversity.Main conclusion
Our findings support previous evidence indicating that traits related to high susceptibility to forest disturbances are convergent or have low phylogenetic signal. More importantly, they reveal that the evolutionary value of disturbed forests is (at least in a phylogenetic sense) much greater than previously thought.20.
Clinton N. Jenkins Benoit Guénard Sarah E. Diamond Michael D. Weiser Robert R. Dunn 《Diversity & distributions》2013,19(8):1084-1092