52 results found
Banks-Leite C, Larrosa C, Carrasco LR, et al., 2021, The suggestion that landscapes should contain 40% of forest cover lacks evidence and is problematic, Ecology Letters, Vol: 24, Pages: 1112-1113, ISSN: 1461-023X
A recent review suggests that forest cover needs to be restored or maintained on at least 40% of land area. In the absence of empirical evidence to support this threshold, we discuss how this suggestion is unhelpful and potentially dangerous. We advocate for regionally defined thresholds to inform conservation and restoration.
Banks-Leite C, Ewers R, Folkard-Tapp H, et al., 2020, Countering the effects of habitat loss, fragmentation, and degradation through habitat restoration, One Earth, Vol: 3, Pages: 672-676, ISSN: 2590-3322
Habitat loss, fragmentation and degradation impacts are the most direct threat to global biodiversity. In this Primer, we discuss how these three forms of habitat transformation are inextricably intertwined, and how their effects on biodiversity and ecosystems are often context-specific. We draw on recent analyses that have explored this context-dependence directly, to discuss how local-scale impacts of habitat transformation are mediated by biogeographic-scale variation in evolutionary histories and species’ geographic ranges. We also discuss how changes to ecosystem functions and services in modified habitats can be just as context-dependent – and how these changes are further obscured by high levels of ecological redundancy in species functions, which can confer resilience to habitat transformation. To avoid the impending extinction of millions of species, it is crucial that the impacts of habitat transformation are mitigated through a combination of preventing further habitat loss while simultaneously extending and repairing the habitats that remain.
Parra-Sanchez E, Banks-Leite C, 2020, The magnitude and extent of edge effects on vascular epiphytes across the Brazilian Atlantic Forest, Scientific Reports, Vol: 10, Pages: 1-11, ISSN: 2045-2322
Edge effects are ubiquitous landscape processes influencing over 70% of forest cover worldwide. However, little is known about how edge effects influence the vertical stratification of communities in forest fragments. We combined a spatially implicit and a spatially explicit approach to quantify the magnitude and extent of edge effects on canopy and understorey epiphytic plants in the Brazilian Atlantic Forest. Within the human-modified landscape, species richness, species abundance and community composition remained practically unchanged along the interior-edge gradient, pointing to severe biotic homogenisation at all strata. This is because the extent of edge effects reached at least 500 m, potentially leaving just 0.24% of the studied landscape unaffected by edges. We extrapolated our findings to the entire Atlantic Forest and found that just 19.4% of the total existing area is likely unaffected by edge effects and provide suitable habitat conditions for forest-dependent epiphytes. Our results suggest that the resources provided by the current forest cover might be insufficient to support the future of epiphyte communities. Preserving large continuous ‘intact’ forests is probably the only effective conservation strategy for vascular epiphytes.
Chan A, Banks-Leite C, 2020, Habitat modification mediates the strength of trophic cascades on oak trees, Perspectives in Ecology and Conservation, Vol: 18, Pages: 313-318, ISSN: 2530-0644
Habitat modification is now a widespread phenomenon, impacting landscape structure, biophysical processes, food webs and biodiversity. These changes have trickle-down effects on trophic cascades: predators often become rarer, increasing prey populations, which then subject plants to higher levels of herbivory. How habitat modification mediates this trophic cascade, however, is poorly understood, and this is particularly true for temperate forests. Here we investigate if the strength of trophic cascades, defined as the magnitude of the effect of bird exclusion on leaf damage, varies along a gradient of increasing habitat modification, from forest interior to forest edge to open habitat, through an experimental manipulation of bird exclusion. We found that habitat modification reduces the number of bird observations, with trophic cascades being three times stronger in the forest interior than edge and open habitats. However, there is no corresponding increase in leaf damage with habitat modification in the presence of birds, suggesting that other taxa or factors may mediate leaf damage in modified habitats. Our findings suggest that even though habitat modification disrupts the functions that birds perform in the ecosystem, overall ecosystem function is not dramatically altered, possibly due to the functional redundancy of birds.
Lima RAFD, Condé PA, Banks-Leite C, et al., 2020, Disentangling the effects of sampling scale and size on the shape of species abundance distributions, PLoS One, Vol: 15, Pages: e0238854-e0238854, ISSN: 1932-6203
Many authors have tried to explain the shape of the species abundance distribution (SAD). Some of them have suggested that sampling spatial scale is an important factor shaping SADs. These suggestions, however, did not consider the indirect and well-known effect of sample size, which increases as samples are combined to generate SADs at larger spatial scales. Here, we separate the effects of sample size and sampling scale on the shape of the SAD for three groups of organisms (trees, beetles and birds) sampled in the Brazilian Atlantic Forest. We compared the observed SADs at different sampling scales with simulated SADs having the same richness, relative abundances but comparable sample sizes, to show that the main effect shaping SADs is sample size and not sampling spatial scale. The effect of scale was minor and deviations between observed and simulated SADs were present only for beetles. For trees, the match between observed and simulated SADs was improved at all spatial scales when we accounted for conspecific aggregation, which was even more important than the sampling scale effect. We build on these results to propose a conceptual framework where observed SADs are shaped by three main factors, in decreasing order of importance: sample size, conspecific aggregation and beta diversity. Therefore, studies comparing SADs across sites or scales should use sampling and/or statistical approaches capable of disentangling these three effects on the shape of SADs.
Harrison MLK, Banks-Leite C, 2020, Edge effects on trophic cascades in tropical rainforests., Conserv Biol, Vol: 34, Pages: 977-987
The cascading effects of biodiversity loss on ecosystem functioning of forests have become more apparent. However, how edge effects shape these processes has yet to be established. We assessed how edge effects alter arthropod populations and the strength of any resultant trophic cascades on herbivory rate in tropical forests of Brazil. We established 7 paired forest edge and interior sites. Each site had a vertebrate-exclosure, procedural (exclosure framework with open walls), and control plot (total 42 plots). Forest patches were surrounded by pasture. Understory arthropods and leaf damage were sampled every 4 weeks for 11 months. We used path analysis to determine the strength of trophic cascades in the interior and edge sites. In forest interior exclosures, abundance of predaceous and herbivorous arthropods increased by 326% and 180%, respectively, compared with control plots, and there were significant cascading effects on herbivory. Edge-dwelling invertebrates responded weakly to exclusion and there was no evidence of trophic cascade. Our results suggest that the vertebrate community at forest edges controls invertebrate densities to a lesser extent than it does in the interior. Edge areas can support vertebrate communities with a smaller contingent of insectivores. This allows arthropods to flourish and indirectly accounts for higher levels of plant damage at these sites. Increased herbivory rates may have important consequences for floristic community composition and primary productivity, as well as cascading effects on nutrient cycling. By interspersing natural forest patches with agroforests, instead of pasture, abiotic edge effects can be softened and prevented from penetrating deep into the forest. This would ensure a greater proportion of forest remains habitable for sensitive species and could help retain ecosystem functions in edge zones.
Lima DO, BanksLeite C, Lorini ML, et al., 2020, Anthropogenic effects on the occurrence of medium‐sized mammals on the Brazilian Pampa biome, Animal Conservation, ISSN: 1367-9430
Hintzen RE, Papadopoulou M, Mounce R, et al., 2020, Relationship between conservation biology and ecology shown through machine reading of 32,000 articles, Conservation Biology, Vol: 34, Pages: 721-732, ISSN: 0888-8892
Conservation biology was founded on the idea that efforts to save nature depend on a scientific understanding of how it works. It sought to apply ecological principles to conservation problems. We investigated whether the relationship between these fields has changed over time through machine reading the full texts of 32,000 research articles published in 16 ecology and conservation biology journals. We examined changes in research topics in both fields and how the fields have evolved from 2000 to 2014. As conservation biology matured, its focus shifted from ecology to social and political aspects of conservation. The 2 fields diverged and now occupy distinct niches in modern science. We hypothesize this pattern resulted from increasing recognition that social, economic, and political factors are critical for successful conservation and possibly from rising skepticism about the relevance of contemporary ecological theory to practical conservation. Article Impact statement: Quantitative literature evaluation reveals that the research topics of ecology and conservation biology are drawing apart. This article is protected by copyright. All rights reserved.
Hatfield J, Barlow J, Joly CA, et al., 2020, Mediation of area and edge effects by adjacent land use, Conservation Biology, Vol: 34, Pages: 395-404, ISSN: 0888-8892
Habitat loss, fragmentation and degradation have pervasive detrimental effects on tropical forest biodiversity, but the role of the surrounding land use (i.e. matrix) in determining the severity of these impacts remains poorly understood. We surveyed bird species across an interior-edge-matrix gradient to assess the effects of matrix type on biodiversity at 49 different sites with varying levels of landscape fragmentation in the Brazilian Atlantic Forest – a highly threatened biodiversity hotspot. Our findings revealed that both area and edge effects are more pronounced in forest patches bordering pasture matrix, while patches bordering Eucalyptus plantation maintained compositionally similar bird communities between the edge and the interior, in addition to exhibiting reduced effects of patch size. These results suggest that the type of matrix in which forest fragments are situated can explain a substantial amount of the widely-reported variability in biodiversity responses to forest loss and fragmentation.
Watling JI, ArroyoRodríguez V, Pfeifer M, et al., 2020, Support for the habitat amount hypothesis from a global synthesis of species density studies, Ecology Letters, Vol: 23, Pages: 674-681, ISSN: 1461-023X
Püttker T, Crouzeilles R, Almeida-Gomes M, et al., 2020, Indirect effects of habitat loss via habitat fragmentation: A cross-taxa analysis of forest-dependent species, Biological Conservation, Vol: 241, Pages: 1-10, ISSN: 0006-3207
Recent studies suggest that habitat amount is the main determinant of species richness, whereas habitat fragmentation has weak and mostly positive effects. Here, we challenge these ideas using a multi-taxa database including 2230 estimates of forest-dependent species richness from 1097 sampling sites across the Brazilian Atlantic Forest biodiversity hotspot. We used a structural equation modeling approach, accounting not only for direct effects of habitat loss, but also for its indirect effects (via habitat fragmentation), on the richness of forest-dependent species. We reveal that in addition to the effects of habitat loss, habitat fragmentation has negative impacts on animal species richness at intermediate (30–60%) levels of habitat amount, and on richness of plants at high (>60%) levels of habitat amount, both of which are mediated by edge effects. Based on these results, we argue that dismissing habitat fragmentation as a powerful force driving species extinction in tropical forest landscapes is premature and unsafe.
Betts MG, Wolf C, Pfeifer M, et al., 2019, Extinction filters mediate the global effects of habitat fragmentation on animals, Science, Vol: 366, Pages: 1236-1239, ISSN: 0036-8075
Habitat loss is the primary driver of biodiversity decline worldwide, but the effects of fragmentation (the spatial arrangement of remaining habitat) are debated. We tested the hypothesis that forest fragmentation sensitivity-affected by avoidance of habitat edges-should be driven by historical exposure to, and therefore species' evolutionary responses to disturbance. Using a database containing 73 datasets collected worldwide (encompassing 4489 animal species), we found that the proportion of fragmentation-sensitive species was nearly three times as high in regions with low rates of historical disturbance compared with regions with high rates of disturbance (i.e., fires, glaciation, hurricanes, and deforestation). These disturbances coincide with a latitudinal gradient in which sensitivity increases sixfold at low versus high latitudes. We conclude that conservation efforts to limit edges created by fragmentation will be most important in the world's tropical forests.
Ewers RM, Barlow J, Banks-Leite C, et al., 2019, Separate authorship categories to recognize data collectors and code developers, NATURE ECOLOGY & EVOLUTION, Vol: 3, Pages: 1610-1610, ISSN: 2397-334X
Vargas-Pellicer P, Watrobska C, Knowles S, et al., 2019, How should we store avian faecal samples for microbiota analyses? Comparing efficacy and cost-effectiveness, JOURNAL OF MICROBIOLOGICAL METHODS, Vol: 165, ISSN: 0167-7012
Larrosa CR, Carrasco LR, Tambosi LR, et al., 2019, Spatial conservation planning with ecological and economic feedback effects, Biological Conservation, Vol: 237, Pages: 308-316, ISSN: 0006-3207
Most spatial conservation prioritisations being implemented across the globe are based on static approaches to conservation planning. These use snapshots of systems to support decision-making. However, ignoring the dynamic nature of systems can result in misleading spatial prioritisations and missed opportunities to encourage participation in conservation programmes. Using a modelling approach, we show that integrating economic and ecological feedbacks into conservation planning improved social and ecological outcomes. We developed an approach that enabled accounting for feedbacks of farmland set-asides using a popular conservation planning tool. We empirically assessed the impact of ignoring feedbacks on plans to restore the Brazilian Atlantic Forest by comparing outcomes of our approach and a widely used static approach. The proposed approach attained better conservation outcomes than a static approach, at about 7% lower cost, while also allowing more farmers to benefit economically from the set-aside scheme through capitalising on the differences between their opportunity costs and the amount paid by the scheme. Accounting for feedbacks led to substantially different areas being prioritised for farmland set-asides, and to more farmers being included in the set-aside scheme. These results show important benefits from understanding, and then working with, feedbacks that inevitably accompany large-scale conservation interventions. Our approach is the first to integrate both environmental and economic feedbacks into spatial conservation planning, and model information rent capture. In doing so, it demonstrates how existing economic incentives can be used to encourage farmers to join a conservation set-aside, while still resulting in a lower overall intervention cost.
Vidal MM, Banks-Leite C, Tambosi LR, et al., 2019, Predicting the non-linear collapse of plant-frugivore networks due to habitat loss, Ecography, ISSN: 0906-7590
Orme CDL, Mayor S, Dos Anjos L, et al., 2019, Publisher Correction: Distance to range edge determines sensitivity to deforestation, Nature Ecology and Evolution, Vol: 3, Pages: 1131-1131, ISSN: 2397-334X
Correction to: Nature Ecology & Evolution https://doi.org/10.1038/s41559-019-0889-z, published online 06 May 2019.
Rodrigues RC, Hasui É, Assis JC, et al., 2019, Atalntic Bird Traits: a data set of bird morphological traits from the Atlantic forests of South America, Ecology, Vol: 100, ISSN: 0012-9658
Scientists have long been trying to understand why the Neotropical region holds the highest diversity of birds on Earth. Recently, there has been increased interest in morphological variation between and within species, and in how climate, topography, and anthropogenic pressures may explain and affect phenotypic variation. Because morphological data are not always available for many species at the local or regional scale, we are limited in our understanding of intra- and interspecies spatial morphological variation. Here, we present the ATLANTIC BIRD TRAITS, a data set that includes measurements of up to 44 morphological traits in 67,197 bird records from 2,790 populations distributed throughout the Atlantic forests of South America. This data set comprises information, compiled over two centuries (1820–2018), for 711 bird species, which represent 80% of all known bird diversity in the Atlantic Forest. Among the most commonly reported traits are sex (n = 65,717), age (n = 63,852), body mass (n = 58,768), flight molt presence (n = 44,941), molt presence (n = 44,847), body molt presence (n = 44,606), tail length (n = 43,005), reproductive stage (n = 42,588), bill length (n = 37,409), body length (n = 28,394), right wing length (n = 21,950), tarsus length (n = 20,342), and wing length (n = 18,071). The most frequently recorded species are Chiroxiphia caudata (n = 1,837), Turdus albicollis (n = 1,658), Trichothraupis melanops (n = 1,468), Turdus leucomelas (n = 1,436), and Basileuterus culicivorus (n = 1,384). The species recorded in the greatest number of sampling localities are Basileuterus culicivorus (n = 243), Trichothraupis melanops (n = 242), Chiroxiphia caudata (n = 210), Platyrinchus mystaceus (n = 208), and Turdus rufiventris (n =&nb
Orme D, Mayor S, dos Anjos L, et al., 2019, Distance to range edge determines sensitivity to deforestation, Nature Ecology and Evolution, Vol: 3, Pages: 886-891, ISSN: 2397-334X
It is generally assumed that deforestation affects a species consistently across space, however populations near their geographic range edge may exist at their niche limits and therefore be more sensitive to disturbance. We found that both within and across Atlantic Forest bird species, populations are more sensitive to deforestation when near their range edge. In fact, the negative effects of deforestation on bird occurrences switched to positive in the range core (>829 km), in line with Ellenberg’s rule. We show that the proportion of populations at their range core and edge varies across Brazil, suggesting deforestation effects on communities, and hence the most appropriate conservation action, also vary geographically.
Hatfield JH, Orme CDL, Banks-Leite C, 2018, Using functional connectivity to predict potential meta-population sizes in the Brazilian Atlantic Forest, Perspectives in Ecology and Conservation, Vol: 16, Pages: 215-220, ISSN: 2530-0644
Habitat loss and fragmentation reduce population sizes and increase isolation between populations. To better understand how functional connectivity is affected by habitat modification over large scales, we here applied a meta-population framework to the Brazilian Atlantic Forest, a highly degraded and fragmented biodiversity hotspot. Other studies have used mainly hypothetical or estimated dispersal values for connectivity calculation which may not be reflective of species requirements. Here, we collated dispersal values for 45 species of birds, 5 mammals and 4 insects and found that 50% of the Atlantic Forest species can cross only up to 150 m of open gaps between forest patches. Because of the high levels of fragmentation, the median size of a functionally connected network of fragments in the Brazilian Atlantic Forest only decreased from 15 ha to 14 ha when the crossable distance considered was reduced from 150 m to 0 m. We show that for species solely reliant on native forest habitat, a large proportion of the remaining Atlantic Forest fragments represent many small and isolated populations with few large connected areas. Our results support further evidence that for future management and restoration to be successful, existing connectivity must be vastly improved to provide forest areas large enough to support viable populations.
Habitat loss is a primary threat to biodiversity across the planet, yet contentious debate has ensued on the importance of habitat fragmentation ‘per se’ (i.e., altered spatial configuration of habitat for a given amount of habitat loss). Based on a review of landscape-scale investigations, Fahrig (2017; Ecological responses to habitat fragmentation per se. Annual Review of Ecology, Evolution, and Systematics 48:1-23) reports that biodiversity responses to habitat fragmentation ‘per se’ are more often positive rather than negative and concludes that the widespread belief in negative fragmentation effects is a ‘zombie idea’. We show that Fahrig's conclusions are drawn from a narrow and potentially biased subset of available evidence, which ignore much of the observational, experimental and theoretical evidence for negative effects of altered habitat configuration. We therefore argue that Fahrig's conclusions should be interpreted cautiously as they could be misconstrued by policy makers and managers, and we provide six arguments why they should not be applied in conservation decision-making. Reconciling the scientific disagreement, and informing conservation more effectively, will require research that goes beyond statistical and correlative approaches. This includes a more prudent use of data and conceptual models that appropriately partition direct vs indirect influences of habitat loss and altered spatial configuration, and more clearly discriminate the mechanisms underpinning any changes. Incorporating these issues will deliver greater mechanistic understanding and more predictive power to address the conservation issues arising from habitat loss and fragmentation.
Hatfield JH, Harrison MLK, Banks-Leite C, 2018, Functional diversity metrics: how they are affected by landscape change and how they represent ecosystem functioning in the tropics, Current Landscape Ecology Reports, Vol: 3, Pages: 35-42, ISSN: 2364-494X
It is generally expected that landscape changes, such as habitat loss and fragmentation, should negatively affect functional diversity metrics, which in turn impact ecosystem functioning. In this review, we search for studies conducted in the tropics and published in the last 10 years to understand how different aspects of landscape change affect functional diversity metrics and how the latter are associated to ecosystem functioning. In total, we found 24 papers that assessed the effects of landscape metrics on functional diversity, evenness, divergence and composition, and although there was a general trend for functional diversity metrics to improve with habitat cover, we found a wide range of responses. Most surprisingly, however, we only found five studies from the tropics assessing the extent to which functional diversity metrics were correlated to measures of ecosystem functioning, and in general, very weak support was found. In conclusion, our results show that it is crucial to first investigate the level to which functional diversity metrics truly represent or may lead to changes in ecosystem functioning, and this is particularly important for animal communities in the tropics. Without such confirmation, there is little reason to pursue further work to reach a consensus regarding how landscape modification affects functional diversity metrics.
Hasui É, Metzger JP, Pimentel RG, et al., 2018, ATLANTIC BIRDS: a data set of bird species from the Brazilian Atlantic Forest, Ecology, Vol: 99, Pages: 497-497, ISSN: 0012-9658
South America holds 30% of the world's avifauna, with the Atlantic Forest representing one of the richest regions of the Neotropics. Here we have compiled a data set on Brazilian Atlantic Forest bird occurrence (150,423) and abundance samples (N = 832 bird species; 33,119 bird individuals) using multiple methods, including qualitative surveys, mist nets, point counts, and line transects). We used four main sources of data: museum collections, on‐line databases, literature sources, and unpublished reports. The data set comprises 4,122 localities and data from 1815 to 2017. Most studies were conducted in the Florestas de Interior (1,510 localities) and Serra do Mar (1,280 localities) biogeographic sub‐regions. Considering the three main quantitative methods (mist net, point count, and line transect), we compiled abundance data for 745 species in 576 communities. In the data set, the most frequent species were Basileuterus culicivorus, Cyclaris gujanensis, and Conophaga lineata. There were 71 singletons, such as Lipaugus conditus and Calyptura cristata. We suggest that this small number of records reinforces the critical situation of these taxa in the Atlantic Forest. The information provided in this data set can be used for macroecological studies and to foster conservation strategies in this biodiversity hotspot. No copyright restrictions are associated with the data set. Please cite this Data Paper if data are used in publications and teaching events.
Pfeifer M, Lefebvre V, Peres CA, et al., 2017, Creation of forest edges has a global impact on forest vertebrates, Nature, Vol: 551, Pages: 187-191, ISSN: 0028-0836
Forest edges influence more than half of the world’s forests and contribute to worldwide declines in biodiversity and ecosystem functions. However, predicting these declines is challenging in heterogeneous fragmented landscapes. Here we assembled a global dataset on species responses to fragmentation and developed a statistical approach for quantifying edge impacts in heterogeneous landscapes to quantify edge-determined changes in abundance of 1,673 vertebrate species. We show that the abundances of 85% of species are affected, either positively or negatively, by forest edges. Species that live in the centre of the forest (forest core), that were more likely to be listed as threatened by the International Union for Conservation of Nature (IUCN), reached peak abundances only at sites farther than 200–400 m from sharp high-contrast forest edges. Smaller-bodied amphibians, larger reptiles and medium-sized non-volant mammals experienced a larger reduction in suitable habitat than other forest-core species. Our results highlight the pervasive ability of forest edges to restructure ecological communities on a global scale.
Hatfield JH, Orme CDL, Tobias JA, et al., 2017, Trait-based indicators of bird species sensitivity to habitat loss are effective within but not across datasets., Ecological Applications, Vol: 28, Pages: 28-34, ISSN: 1051-0761
Species' traits have been widely championed as the key to predicting which species are most threatened by habitat loss, yet previous work has failed to detect trends that are consistent enough to guide large-scale conservation and management. Here we explore whether traits and environmental variables predict species sensitivity to habitat loss across two datasets generated by independent avifaunal studies in the Atlantic Forest of Brazil, both of which detected a similar assemblage of species, and similar species-specific responses to habitat change, across an overlapping sample of sites. Specifically, we tested whether 25 distributional, climatic, ecological, behavioral and morphological variables predict sensitivity to habitat loss among 196 bird species, both within and across studies, and when data were analysed as occurrence or abundance. We found that 4-9 variables showed high explanatory power within a single study or dataset, but none performed as strong predictors across all datasets. Our results demonstrate that the use of species traits to predict sensitivity to anthropogenic habitat loss can produce predictions that are species- and site-specific and not scalable to whole regions or biomes, and thus should be used with caution. This article is protected by copyright. All rights reserved.
Ulrich W, Banks-Leite C, De Coster G, et al., 2017, Environmentally and behaviourally mediated co-occurrence of functional traits in bird communities of tropical forest fragments, Oikos, Vol: 127, Pages: 274-284, ISSN: 0030-1299
Two major theories of community assembly - based on the assumption of 'limiting similarity' or 'habitat filtering', respectively - predict contrasting patterns in the spatial arrangement of functional traits. Previous analyses have made progress in testing these predictions and identifying underlying processes, but have also pointed to theoretical as well as methodological shortcomings. Here we applied a recently developed methodology for spatially explicit analysis of phylogenetic meta-community structure to study the pattern of co-occurrence of functional traits in Afrotropical and Neotropical bird species inhabiting forest fragments. Focusing separately on locomotory, dietary, and dispersal traits, we tested whether environmental filtering causes spatial clustering, or competition leads to spatial segregation as predicted by limiting similarity theory. We detected significant segregation of species co-occurrences in African fragments, but not in the Neotropical ones. Interspecific competition had a higher impact on trait co-occurrence than filter effects, yet no single functional trait was able to explain the observed degree of spatial segregation among species. Despite high regional variability spanning from spatial segregation to aggregation, we found a consistent tendency for a clustered spatial patterning of functional traits among communities in fragmented landscapes, particularly in non-territorial species. Overall, we show that behavioural effects, such as territoriality, and environmental effects, such as the area of forest remnants or properties of the landscape matrix in which they are embedded, can strongly affect the pattern of trait co-occurrence. Our findings suggest that trait-based analyses of community structure should include behavioural and environmental covariates, and we here provide an appropriate method for linking functional traits, species ecology and environmental conditions to clarify the drivers underlying spatial patterns of species c
Resasco J, Bruna EM, Haddad NM, et al., 2016, The contribution of theory and experiments to conservation in fragmented landscapes, Ecography, Vol: 40, Pages: 109-118, ISSN: 0906-7590
The clearing and fragmentation of terrestrial ecosystems is commonly acknowledged as a major cause of the decline of biodiversity. These and other predicted responses to habitat fragmentation are derived from theory, which ecologists have tested with empirical approaches ranging from observations to experimental manipulations. These empirical approaches have also identified areas of theory in need of additional development. For example, experimental studies of fragmentation have provided insights such as the key role played by the matrix surrounding fragments, the importance of edge effects, and the impacts of corridors linking fragments with one another. Much less clear, however, is the extent to which these theoretical and empirical studies – while advancing our conceptual understanding of ecological responses to landscape change – help guide management and conservation practice. We review lessons learned from landscape-scale fragmentation experiments and observational studies, present the results of a survey of fragmentation and conservation experts which probed for links and mismatches between fragmentation studies and conservation practice, and discuss how future studies can contribute to conservation practice. Our survey showed that respondents consider fragmentation theory and empirical studies and their findings important for guiding conservation and management practices. The survey also identified that there are disconnects between what is typically studied by fragmentation ecologists and factors that are central to the practice of biodiversity conservation, notably, community-based human dimensions (e.g. economic, social, health issues), policy and governance, ecosystem services, eco-evolutionary responses of species, and interaction of multiple threats to biodiversity and ecosystem processes. We discuss how these disconnects can present opportunities for experiments to continue to provide valuable recommendations for conservation practice in f
Collins CD, Banks-Leite C, Brudvig LA, et al., 2016, Fragmentation affects plant community composition over time, Ecography, Vol: 40, Pages: 119-130, ISSN: 0906-7590
Habitat fragmentation can lead to major changes in community composition, but little is known about the dynamics of these changes, or how community trajectories are affected by the initial state of habitat maturity. We use four landscape-scale experiments from different biogeographic regions to understand how plant community composition responds to fragmentation over decades. Within each experiment, we consider first whether plant communities in the most-fragmented treatments diverge in composition from plant communities in the least-fragmented treatments. Second, because communities embedded in different fragments may become more similar to one another over time (biotic homogenization), we asked whether beta diversity – compositional variation across space – declines among fragments over time. Third, we assessed whether fragmentation alters the degree to which temporal change in fragmented landscapes is due to ordered species losses and gains (nestedness) versus species replacements (turnover). For each of these three questions, we contrasted patterns of compositional change in mature communities following fragmentation (disassembly; n = 2 experiments) with patterns in newly-developing plant communities in fragments cleared of vegetation (assembly; n = 2 experiments).In the two studies where communities were disassembling, community composition in the most-fragmented habitats diverged from that in least-fragmented habitats. Beta diversity within a fragmentation treatment did not change over time at any of the four sites. In all four experiments, temporal patterns of compositional change were due mostly to species turnover, although nestedness played a role in the least-fragmented sites in two of the studies. Overall, the impacts on community composition varied among landscape experiments, and divergence may have been affected by the maturity of the plant community. Future comparisons across ecosystems that account for species identities (vs simply richn
Neate-Clegg MHC, Morshuis EC, Banks-Leite C, 2016, Edge effects in the avifaunal community of riparian rain-forest tracts in Tropical North Queensland, Journal of Tropical Ecology, Vol: 32, Pages: 280-289, ISSN: 1469-7831
Most evidence suggests anthropogenic edges negatively affect rain-forest bird communities but little has been done to test this in Australasia. In this study, avifaunal detection frequency, species richness and community composition were compared between the edge and interior and between flat and more complex-shaped edges of riparian rain-forest tracts in Tropical North Queensland. The detection frequency and richness of guilds based on diet, foraging strata and habitat specialism were also compared. This study detected 15.1% more birds at the rain-forest edge compared with the interior but no difference in species richness. Edge shape had no effect on detection frequency or richness. Many guilds (subcanopy, closed forest, frugivorous and insectivorous species) experienced increased detection frequency at the edge relative to the interior, but for some guilds this response was reduced (habitat generalists) or reversed (understorey and mixed-flock species) along complex edges. Overall community composition was affected by edge distance but not by edge shape. Edge habitat was shorter and had more open canopy than the interior, supporting habitat-based explanations for the observed avifaunal edge effects. These results suggest generally positive edge effects in Australian rain-forest bird communities, possibly reflecting local resource distributions or a disturbance-tolerant species pool.
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