共查询到20条相似文献,搜索用时 437 毫秒
1.
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.2.
Zero‐sum landscape effects on acorn predation associated with shifts in granivore insect community in new holm oak (Quercus ilex) forests
下载免费PDF全文
![点击此处可从《Diversity & distributions》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Helena Ruiz‐Carbayo Raúl Bonal Joan Pino Josep Maria Espelta 《Diversity & distributions》2018,24(4):521-534
Aim
Landscape attributes can determine plant–animal interactions via effects on the identity and abundance of the involved species. As most studies have been conducted in a context of habitat loss and fragmentation, we know very little about interaction assembly in new habitats from a landscape approach. This study aimed to test the effect of forest age and connectivity on acorn predation by a guild of predator insects differing in dispersal ability and resilience mechanisms: two weevils (Curculio elephas and C. glandium) and one moth (Cydia fagiglandana) in expanding Quercus ilex forests.Location
Barcelona, Spain.Methods
We assessed the proportion of infested acorns and identified the predator at the species level in five patches of connected old forests, connected new forests and isolated new forests. Effects of habitat age and connectivity at three scales (tree, patch and landscape) were analysed using generalized linear mixed‐effects models.Results
Predation by weevils was positively associated with old connected forests, while moths, with better dispersal ability, were able to predate upon all patches equally. Moreover, C. elephas, the weevil with lower dispersal ability, exhibited colonization credits in the new isolated patches. In spite of these changes in the guild of seed predators, the proportion of infested acorns was non‐significantly different among forests.Main conclusions
The guild of seed predators may vary depending on forest age and connectivity. However, because those with higher dispersal ability may replace less mobile species, this resulted in zero‐sum effects of landscape attributes on acorn predation (i.e., similar predation rates in well‐connected old forests vs. isolated new forests).3.
Small variations in climate and soil conditions may have greater influence on multitaxon species occurrences than past and present human activities in temperate mountain forests
下载免费PDF全文
![点击此处可从《Diversity & distributions》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Aim
Human activity is known to greatly influence species occurrences. In forest ecosystems, biodiversity is often believed to be influenced by two habitat characteristics: (1) forest continuity, related to a minimum length of time in a wooded state since a threshold date; and (2) stand maturity, related to the availability of late‐developmental‐forest attributes. In a context of ongoing global biodiversity loss, qualifying the effect of past and present human activity on forest ecosystems while taking into account variations in abiotic factors is of primary importance for conservation.Location
Temperate mountain forests in the Northern Alps.Method
Based upon a sampling design crossing forest continuity (ancient vs. Recent) and stand maturity (mature vs. overmature), and while controlling for the effect of two major environmental factors, soil and climate, we explored the individual response of saproxylic beetle, springtail, herbaceous plant and epiphytic macrolichen species to past and present human activity.Results
Forest continuity influenced the occurrence of relatively few species, indicating that past land use had almost no legacy effect on the species occurring in the study forests today. In contrast, stand maturity had an overall positive effect on species occurrences. However, our results showed that species occurrences were more obviously influenced by abiotic conditions. Indeed, beyond the effect of continuity and maturity factors, the probability of presence of numerous species was best explained by climate and soil.Main conclusions
Overall, we show that species occurrence was more influenced by stand maturity than by forest continuity, but also that site‐specific characteristics were of great importance in explaining the probability of presence for numerous species. In the ecological context of alpine forests, these findings emphasize the need to better control for climatic and edaphic conditions in order to (1) improve accuracy in predicting species occurrence and (2) better design areas of conservation interest.4.
Land use legacy effects on woody vegetation in agricultural landscapes of south‐western Ethiopia
下载免费PDF全文
![点击此处可从《Diversity & distributions》网站下载免费的PDF全文](/ch/ext_images/free.gif)
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.5.
Phylogenetic dimension of tree communities reveals high conservation value of disturbed tropical rain forests
下载免费PDF全文
![点击此处可从《Diversity & distributions》网站下载免费的PDF全文](/ch/ext_images/free.gif)
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.6.
Climate change‐driven extinctions of tree species affect forest functioning more than random extinctions
下载免费PDF全文
![点击此处可从《Diversity & distributions》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Aim
Climate change affects forest functioning not only through direct physiological effects such as modifying photosynthesis and growing season lengths, but also through indirect effects on community composition related to species extinctions and colonizations. Such indirect effects remain poorly explored in comparison with the direct ones. Biodiversity–ecosystem functioning (BEF) studies commonly examine the effects of species loss by eliminating species randomly. However, species extinctions caused by climate change will depend on the species’ vulnerability to the new environmental conditions, thus occurring in a specific, non‐random order. Here, we evaluated whether successive tree species extinctions, according to their vulnerability to climate change, impact forest functions differently than random species losses.Location
Eleven temperate forests across a gradient of climatic conditions in central Europe.Methods
We simulated tree community dynamics with a forest succession model to study the impact of species loss on the communities’ aboveground biomass, productivity and temporal stability. Tree species were removed from the local pool (1) randomly, and according to (2) their inability to be recruited under a warmer climate or (3) their increased mortality under drier conditions.Results
Results showed that non‐random species loss (i.e., based on their vulnerability to warmer or drier conditions) changed forest functioning at a different rate, and sometimes direction, than random species loss. Furthermore, directed extinctions, unlike random, triggered tipping points along the species loss process where forest functions were strongly impacted. These tipping points occurred after fewer extinctions in forests located in the coldest areas, where ecosystem functioning relies on fewer species.Main conclusions
We showed that the extinction of species in a deterministic and mechanistically motivated order, in this case the species vulnerability to climate change, strengthens the selection effect of diversity on ecosystem functioning. BEF studies exploring the impact of species loss on ecosystem functioning using random extinctions thus possibly underestimate the potential effect of biodiversity loss when driven by a directional force, such as climate change.7.
Liba Pejchar Travis Gallo Mevin B. Hooten Gretchen C. Daily 《Diversity & distributions》2018,24(6):811-819
Aim
Ecological restoration is critical for recovering biodiversity and ecosystem services, yet designing interventions to achieve particular outcomes remains fraught with challenges. In the extensive regions where non‐native species are firmly established, it is unlikely that historical conditions can be fully reinstated. To what degree, and how rapidly, can human‐dominated areas be shifted via restoration into regimes that benefit target species, communities or processes?Location
We explore this question in a >20‐year‐old reforestation effort underway at Hakalau Forest National Wildlife Refuge in montane Hawaii. This large‐scale planting of Acacia koa trees is designed to secure populations of globally threatened bird species by transitioning the site rapidly from pasture to native forest.Methods
We surveyed all forest birds in multiple corridors of young planted trees, remnant corridors of mature trees along gulches and at sites within mature forest. Using a Bayesian hierarchical approach, we identified which factors (distance from forest, habitat type and surrounding tree cover) had the most important influence on native and exotic bird abundance in the reforestation area.Results
We found that 90% of native and exotic bird species responded quickly, occupying corridors of native trees approximately a decade after planting. However, native and exotic forest birds responded to markedly different characteristics of the reforested area. Native bird abundance was strongly predicted by proximity to mature forest and remnant corridors; conversely, exotic bird abundance was best predicted by overall tree cover throughout the area reforested.Main conclusions
Our results demonstrate that large‐scale tree planting in corridors adjacent to mature forest can catalyse rapid recovery (both increased abundance and expanded distribution) of forest birds and that it is possible to design reforestation to benefit native species in novel ecosystems.8.
Aim
Across the tropics, large‐bodied mammal species are threatened by rapid and widespread forest habitat conversion by either commercial logging or agricultural expansion. How such species use these habitats is an important area of research for guiding their future management. The tropical forest‐dwelling sun bear, Helarctos malayanus, is the least known of the eight bear species. Consequently, the IUCN/SSC Bear Specialist Group ranks research on this species as a top priority. This study aims to investigate landscape variables that influence sun bear habitat use in forests under varying levels of degradation and protection.Location
A 20,998 km2 Sumatra forest landscape covering Kerinci Seblat National Park (KSNP), Batang Hari Protection Forest (BHPF) and neighbouring logging and agricultural concessions.Methods
An occupancy‐based sampling technique using detection/non‐detection data with 10 landscape covariates was applied in six study areas that operated a total of 125 camera traps. The potential differences between habitat use (ψ) of sun bears were first modelled with broad‐scale covariates of study area, land‐use types and forest type. Sun bear habitat use was then investigated with the finer‐scale landscape features associated within these areas.Results
From 10,935 trap nights, sun bears were recorded at altitudes ranging from 365 to 1791 m. At a broad‐scale, habitat use increased with protection status, being highest in KSNP (0.688 ± 0.092, ± SE) and BHPF (0.621 ± 0.110) compared to production (0.418 ± 0.121) and convertible (0.286 ± 0.122) forests. Within these areas, sun bears showed a preference for forest that was further from public roads and villages and at a lower elevation.Main conclusions
The habitat suitability model identified several high‐quality habitat patches outside of the priority conservation areas for immediate protection. Consequently, conservation management strategies should emphasize the importance of high conservation value forests and prohibit further conversion of threatened lowland forests.9.
Ecological correlates of mammal β‐diversity in Amazonian land‐bridge islands: from small‐ to large‐bodied species
下载免费PDF全文
![点击此处可从《Diversity & distributions》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Ana Filipa Palmeirim Maíra Benchimol José Carlos Morante‐Filho Marcus Vinícius Vieira Carlos A. Peres 《Diversity & distributions》2018,24(8):1109-1120
Aim
Mega hydroelectric dams have become one of the main drivers of biodiversity loss in the lowland tropics. In these reservoirs, vertebrate studies have focused on local (α) diversity measures, whereas between‐site (β) diversity remains poorly assessed despite its pivotal importance in understanding how species diversity is structured and maintained. Here, we unravel the patterns and ecological correlates of mammal β‐diversity, including both small (SM) and midsized to large mammal species (LM) across 23 islands and two continuous forest sites within a mega hydroelectric reservoir.Location
Balbina Hydroelectric Dam, Central Brazilian Amazonia.Methods
Small mammals were sampled using live and pitfall traps (48,350 trap‐nights), and larger mammals using camera traps (8,160 trap‐nights). β‐diversity was examined for each group using multiplicative diversity decomposition of Hill numbers, which considers the importance of rare, common and dominant species, and tested to what extent those were related to a set of environmental characteristics measured at different spatial scales.Results
β‐diversity for both mammal groups was higher when considering species presence–absence. When considering species abundance, β‐diversity was significantly higher for SM than for LM assemblages. Habitat variables, such as differences in tree species richness and percentage of old‐growth trees, were strong correlates of β‐diversity for both SMs and LMs. Conversely, β‐diversity was weakly related to patch and landscape characteristics, except for LMs, for which β‐diversity was correlated with differences in island sizes.Main conclusions
The lower β‐diversity of LMs between smaller islands suggests subtractive homogenization of this group. Although island size plays a major role in structuring mammal α‐diversity in several land‐bridge islands, local vegetation characteristics were additional key factors determining β‐diversity for both mammal groups. Maintaining the integrity of vegetation characteristics and preventing the formation of a large set of small islands within reservoirs should be considered in long‐term management plans in both existing and planned hydropower development in lowland tropical forests.10.
Exploring invasibility with species distribution modeling: How does fire promote cheatgrass (Bromus tectorum) invasion within lower montane forests?
下载免费PDF全文
![点击此处可从《Diversity & distributions》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Aim
Cheatgrass (Bromus tectorum) is notorious for creating positive feedbacks that facilitate vegetation type conversion within sagebrush steppe ecosystems in the western United States. Similar dynamics may exist in adjacent lower montane forest. However, fire‐forest‐cheatgrass dynamics have not been examined. We used species distribution modeling to answer three questions about fire and invasibility in lower montane forests: (Q1) Does fire create more suitable habitat for cheatgrass? (Q2) If so, which site attributes are altered to increase site suitability? (Q3) Does fire increase connectivity among suitable habitat and enhance spread?Location
Shoshone National Forest, Wyoming, USA.Methods
We measured cheatgrass presence–absence in 93 plots within Interior Douglas‐fir (Pseudotsuga menziesii var. glauca) forests. Random Forests predicted cheatgrass distribution with and without fire using nine site attributes: elevation, slope, aspect, solar radiation, annual precipitation, maximum temperature in July, minimum temperature in January, forest canopy cover and distance to nearest trail or road. Additionally, invasion pathways and spread were mapped using Circuitscape.Results
Cheatgrass distribution was controlled by topographic and climate variables in the absence of fire. In particular, cheatgrass was most likely to occur at low elevation along dry, south‐ and east‐facing slopes. High‐severity fire increased potential cheatgrass distribution when forest canopy cover was reduced to below 30%. This process created new invasion pathways, which enhanced cheatgrass spread when modelled in Circuitscape.Main conclusions
Our study showed that in the absence of fire, drier south‐ and east‐facing slopes at low elevation are most susceptible to cheatgrass invasion. However, high‐severity fire increased the total area susceptible to invasion—allowing cheatgrass to expand into previously unsuitable sites within lower montane forests in the western United States. These results are important for present day management and reflect that integrating responses to disturbance in species distribution models can be critical for making predictions about dynamically changing systems.11.
Ignoring spatial heterogeneity in social conditions overestimates extinction risk of aquatic macrophytes
下载免费PDF全文
![点击此处可从《Diversity & distributions》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Aim
Abandoned lands are expanding globally due to depopulation in rural areas; biodiversity is declining due to the cessation of traditional management practices. However, the awareness of abandonment as a serious threat is still limited. Knowledge of the influence of the responsible factors on the assessment of regional extinction risk of species due to abandonment is sparse although it is indispensable for conservation decision‐making. This study aimed to clarify the influence of the heterogeneity in abandonment risk and interspecies differences in sensitivity to abandonment on regional species extinction risk and to identify the attributes of the species whose extinction risk is prone to be assessed inaccurately by ignoring the abandonment risk.Location
Awaji Island, Hyogo, Western Japan.Methods
We assessed the extinction risk of 64 species of macrophytes under four scenarios: 2 × 2 combinations whether to incorporate interspecies differences in sensitivity to abandonment and the abandonment risk, respectively.Results
Ignoring the abandonment risk overestimated the extinction risk of most species by 10%, whereas ignoring interspecies differences in sensitivity did not significantly affect the extinction risk. Ignoring the abandonment risk overestimated the extinction risk of emergent plants by 12%, whereas it underestimated that of free‐floating plants or threatened plants by 5%. Spatial bias in abandonment risk markedly reduced the correlation between the extinction risk and the frequency of species occurrence.Main conclusions
The abandonment risk was more effective in accurately assessing the extinction risk due to abandonment than interspecies differences in sensitivity. Extinction risk of emergent, free‐floating or threatened species were assessed inaccurately by ignoring the abandonment risk. Focusing only on the area of occurrence or the extent of occurrence of a species as a surrogate for its extinction risk is likely to produce inaccurate assessments, and thus should be avoided.12.
David L. Vergara‐Tabares Martjan Lammertink Ernesto G. Verga Alejandro A. Schaaf Javier Nori 《Diversity & distributions》2018,24(5):640-651
Aim
As a result of their ecological traits, woodpeckers (Picidae, Aves) are highly sensitive to forest cover change. We explored the current land cover in areas of high species richness of woodpeckers to determinate regions where urgent conservation actions are needed. In addition, we identified woodpecker species that are sensitive to forest loss and that have high levels of human habitat modification and low levels of protection (through protected areas) in their distribution ranges.Location
Global.Methods
We joined available range maps for all extant 254 woodpecker species with information of their conservation status and tolerances to human habitat modifications and generated a richness map of woodpecker species worldwide. Then, we associated this information (the richness pattern and individual species’ maps) with land cover and protected areas (PAs) maps.Result
We found that the foremost woodpecker species richness hotspot is in Southeast Asia and is highly modified. At the second species richness hotspot in the eastern Andes, we observed a front of deforestation at its southern extreme and a greater deforested area in its northern extreme but most of its area remains with forest coverage. At the species level, 17 species that are sensitive to forest modification experience extensive deforestation and have low extents of PAs in their ranges.Main conclusions
The most diverse woodpecker hotspots are mostly occupied by human‐modified landscapes, and a large portion of the species there avoids anthropogenic environments. The level of representation of woodpecker species in PAs is low as a global general pattern, although slightly better in Asia. Our global analysis of threats to woodpecker from land use patterns reiterates the urgent conservation needs for Southeast Asian forests. Finally, based on our results, we recommend a re‐evaluation for inclusion in the Red List of five woodpecker species.13.
Interglacial refugia on tropical mountains: Novel insights from the summit rat (Rattus baluensis), a Borneo mountain endemic
下载免费PDF全文
![点击此处可从《Diversity & distributions》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Miguel Camacho‐Sanchez Irene Quintanilla Melissa T. R. Hawkins Fred Y. Y. Tuh Konstans Wells Jesus E. Maldonado Jennifer A. Leonard 《Diversity & distributions》2018,24(9):1252-1266
Aim
The genetics of organisms currently isolated in refugia has received little attention compared to post‐glacial expansions. We study the population history and connectivity of a rat endemic to montane habitat in Borneo to better understand the history and potential of populations in interglacial mountain refugia.Location
Sabah, Borneo, Malaysia.Methods
We performed a field survey of the summit rat (Rattus baluensis) on two mountains, Mt. Kinabalu and Mt. Tambuyukon, its entire known distribution. We sequenced mitogenomes and 27 introns (19 of which were polymorphic) in 49 individuals from both populations. We analysed their current genetic structure and diversity, and inferred their demographic history with approximate Bayesian computation.Results
Summit rats were tightly associated with mountain mossy forest and scrubland above 2,000 m, facilitating the prediction of their past and future distributions. The genetic analysis supports a Holocene fragmentation of a larger population into smaller ones that are now isolated in interglacial refugia on mountaintops. These findings are consistent with climatic reconstructions and the retreat of upland forest to higher elevations after the Last Glacial Maximum (LGM), ~21 kya.Main conclusions
The two isolated populations of summit rats formed through the upland shift of their habitat after the LGM. The current trend of global warming will likely lead to diminishing suitable upland habitat and result in the extinction of the population on Mt. Tambuyukon. The population on Mt. Kinabalu, the higher peak, could persist at higher elevations, highlighting the singular value of high tropical mountains as reservoirs of biodiversity during past and ongoing climate change.14.
Modelling the distribution and compositional variation of plant communities at the continental scale
下载免费PDF全文
![点击此处可从《Diversity & distributions》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Borja Jiménez‐Alfaro Susana Suárez‐Seoane Milan Chytrý Stephan M. Hennekens Wolfgang Willner Michal Hájek Emiliano Agrillo Jose M. Álvarez‐Martínez Ariel Bergamini Henry Brisse Jörg Brunet Laura Casella Daniel Dítě Xavier Font François Gillet Petra Hájková Florian Jansen Ute Jandt Zygmunt Kącki Jonathan Lenoir John S. Rodwell Joop H. J. Schaminée Lucia Sekulová Jozef Šibík Željko Škvorc Ioannis Tsiripidis 《Diversity & distributions》2018,24(7):978-990
Aim
We investigate whether (1) environmental predictors allow to delineate the distribution of discrete community types at the continental scale and (2) how data completeness influences model generalization in relation to the compositional variation of the modelled entities.Location
Europe.Methods
We used comprehensive datasets of two community types of conservation concern in Europe: acidophilous beech forests and base‐rich fens. We computed community distribution models (CDMs) calibrated with environmental predictors to predict the occurrence of both community types, evaluating geographical transferability, interpolation and extrapolation under different scenarios of sampling bias. We used generalized dissimilarity modelling (GDM) to assess the role of geographical and environmental drivers in compositional variation within the predicted distributions.Results
For the two community types, CDMs computed for the whole study area provided good performance when evaluated by random cross‐validation and external validation. Geographical transferability provided lower but relatively good performance, while model extrapolation performed poorly when compared with interpolation. Generalized dissimilarity modelling showed a predominant effect of geographical distance on compositional variation, complemented with the environmental predictors that also influenced habitat suitability.Main conclusions
Correlative approaches typically used for modelling the distribution of individual species are also useful for delineating the potential area of occupancy of community types at the continental scale, when using consistent definitions of the modelled entity and high data completeness. The combination of CDMs with GDM further improves the understanding of diversity patterns of plant communities, providing spatially explicit information for mapping vegetation diversity and related habitat types at large scales.15.
Assessing habitat loss and fragmentation and their effects on population viability of forest specialist birds: Linking biogeographical and population approaches
下载免费PDF全文
![点击此处可从《Diversity & distributions》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Mario A. Carvajal Alberto J. Alaniz Cecilia Smith‐Ramírez Kathryn E. Sieving 《Diversity & distributions》2018,24(6):820-830
Aim
Biogeographic approaches usually have been developed apart from population ecology, resulting in predictive models without key parameters needed to account for reproductive and behavioural limitations on dispersal. Our aim was to incorporate fully spatially explicit population traits into a classic species distribution model (SDM) using Geographic Information Systems (GIS), aiming at conservation purposes.Location
Southern South America.Methods
Our analysis incorporates the effects of habitat loss and fragmentation on population viability and therefore provides insights into how much spatially explicit population traits can improve the SDM prediction of habitable habitat. We utilized a well‐studied focal endemic bird of South American temperate rainforests (Scelorchilus rubecula). First, at a large scale, we assessed the historical extent habitat based on climate envelopes in an SDM. Second, we used a land cover change analysis at a regional scale to account for recent habitat loss and fragmentation. Third, we used empirically derived criteria to predict population responses to fragmented forest landscapes to identify actual losses of habitat and population. Then we selected three sites of high conservation value in southern Chile and applied our population model. Finally, we discuss the degree to which spatially explicit population traits can improve the SDM output without intervening in the modelling process itself.Results
We found a historical habitat loss of 39.12% and an additional forest cover loss of 3.03% during 2000–2014; the latter occurred with a high degree of fragmentation, reducing the overall estimation of (1) carrying capacity by ?82.4%, ?33.1% and ?45.1% and (2) estimated number of pairs on viable populations by ?84.1%, ?33.0% and ?54.6% on the three selected sites.Main conclusion
We conclude that our approach sharpened the SDM prediction on environmental suitability by 54.4%, adjusting the habitable area by adding population parameters through GIS, and allowing to incorporate other phenomena as fragmentation and habitat loss.16.
Ecological traits modulate bird species responses to forest fragmentation in an Amazonian anthropogenic archipelago
下载免费PDF全文
![点击此处可从《Diversity & distributions》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Anderson Saldanha Bueno Sidnei M. Dantas Luiza Magalli Pinto Henriques Carlos A. Peres 《Diversity & distributions》2018,24(3):387-402
Aim
We assessed patterns of avian species loss and the role of morpho‐ecological traits in explaining species vulnerability to forest fragmentation in an anthropogenic island system. We also contrasted observed and detectability‐corrected estimates of island occupancy, which are often used to infer species vulnerability.Location
Tucuruí Hydroelectric Reservoir, eastern Brazilian Amazonia.Methods
We surveyed forest birds within 36 islands (3.4–2,551.5 ha) after 22 years of post‐isolation history. We applied species–area relationships to assess differential patterns of species loss among three data sets: all species, forest specialists and habitat generalists. After controlling for phylogenetic non‐independence, we used observed and detectability‐corrected estimates of island occupancy separately to build competing models as a function of species traits. The magnitude of the difference between these estimates of island occupancy was contrasted against species detectability.Results
The rate of species loss as a function of island area reduction was higher for forest specialists than for habitat generalists. Accounting for the area effect, forest fragmentation did not affect the overall number of species regardless of the data set. Only the interactive model including natural abundance, habitat breadth and geographic range size was strongly supported for both estimates of island occupancy. For 30 species with detection probabilities below 30%, detectability‐corrected estimates were at least tenfold higher than those observed. Conversely, differences between estimates were negligible or non‐existent for all 31 species with detection probabilities exceeding 45.5%.Main conclusions
Predicted decay of avian species richness induced by forest loss is affected by the degree of habitat specialisation of the species under consideration, and may be unrelated to forest fragmentation per se. Natural abundance was the main predictor of species island occupancy, although habitat breadth and geographic range size also played a role. We caution against using occupancy models for low‐detectability species, because overestimates of island occupancy reduce the power of species‐level predictions of vulnerability.17.
Combined exposure to hydroelectric expansion,climate change and forest loss jeopardies amphibians in the Brazilian Amazon
下载免费PDF全文
![点击此处可从《Diversity & distributions》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Yuri B. da Silva e Silva Bruno R. Ribeiro Fernanda Thiesen Brum Britaldo Soares‐Filho Rafael Loyola Fernanda Michalski 《Diversity & distributions》2018,24(8):1072-1082
Aim
Human‐driven impacts constantly threat amphibians, even in largely protected regions such as the Amazon. The Brazilian Amazon is home to a great diversity of amphibians, several of them currently threatened with extinction. We investigated how climate change, deforestation and establishment of hydroelectric dams could affect the geographic distribution of Amazonian amphibians by 2030 and midcentury.Location
The Brazilian Amazon.Methods
We overlapped the geographic distribution of 255 species with the location of hydroelectric dams, models of deforestation and climate change scenarios for the future.Results
We found that nearly 67% of all species and 54% of species with high degree of endemism within the Legal Brazilian Amazon would lose habitats due to the hydroelectric overlapping. In addition, deforestation is also a potential threat to amphibians, but had a smaller impact compared to the likely changes in climate. The largest potential range loss would be caused by the likely increase in temperature. We found that five amphibian families would have at least half of the species with over 50% of potential distribution range within the Legal Brazilian Amazon limits threatened by climate change between 2030 and 2050.Main conclusions
Amphibians in the Amazon are highly vulnerable to climate change, which may cause, directly or indirectly, deleterious biological changes for the group. Under modelled scenarios, the Brazilian Government needs to plan for the development of the Amazon prioritizing landscape changes of low environmental impact and economic development to ensure that such changes do not cause major impacts on amphibian species while reducing the emission of greenhouse gases.18.
Species’ thermal ranges predict changes in reef fish community structure during 8 years of extreme temperature variation
下载免费PDF全文
![点击此处可从《Diversity & distributions》网站下载免费的PDF全文](/ch/ext_images/free.gif)
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.19.
Landscape correlates of forest plant invasions: A high‐resolution analysis across the eastern United States
下载免费PDF全文
![点击此处可从《Diversity & distributions》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Kurt Riitters Kevin Potter Basil V. Iannone III Christopher Oswalt Songlin Fei Qinfeng Guo 《Diversity & distributions》2018,24(3):274-284
Aim
Invasive species occurrence is often related to the anthropogenic context of a given area. Quantifying the effects of roads is of particular interest as roads are a major vector for invasion. Our objective was to further quantify the effects of roads on forest plant invasion through a macroscale, high‐resolution investigation to assist effective invasion control and mitigation.Location
Eastern United States.Methods
Using invasive plant data from 23,039 forest inventory plots in 13 ecological provinces, we employed logistic regression to relate the odds of invasion to distance from a road, with adjustments for broadscale differences attributable to ecological provinces, and local scale differences in productivity, forest fragmentation and land use.Results
The overall proportion (P) of invaded plots was 0.58 (0.65 for plots within 50 m of a road), and the highest odds (P/1 ? P) of invasion were found in relatively more productive, fragmented forest in landscapes with more than 10% agriculture or developed land cover. Wald chi‐square statistics indicated the best predictor of the odds of invasion was ecological province, followed by land use, productivity, forest fragmentation and distance from a road. Depending on the province, the adjusted odds of invasion decreased by up to 23% (typically 4%–10%) per 100 m distance from a road. The adjusted probability of invasion approached zero in only three provinces, for the least productive, least fragmented forest that was at least 2,000 m from a road in landscapes with less than 10% agricultural or developed land cover.Main conclusions
In the eastern United States, the existence of a nearby road is less important than the landscape context associated with the road. A purely road‐mediated effect has little practical meaning because anthropogenic activities and roads are pervasive and confounded.20.
Invasion lags: The stories we tell ourselves and our inability to infer process from pattern
下载免费PDF全文
![点击此处可从《Diversity & distributions》网站下载免费的PDF全文](/ch/ext_images/free.gif)