Habitat Matrix Research Articles

Scale-Dependent Habitat Nestedness and Its Implications for Anuran Conservation in the Chengdu Region: A Multi-Extent Analysis.

Nestedness in community ecology predicts that species in a species-poor site should be a subset of species of a species-rich site. A variety of ecological mechanisms have been offered to explain community nestedness; however, few studies have systematically discussed the issue of scale dependence when interpreting community nestedness. This study conducted surveys of anuran species data in the vicinity of Chengdu, Sichuan, in the summers of 2019-2020, using the transect method. The study area was divided into 23 sampling sites and 8 regions to explore the relationship between environmental factors and the nested distribution pattern of anuran communities under different sampling extents (with sampling buffers set at 1 km, 2 km, and 5 km). The WNODF (weighted-nestedness metric based on overlap and decreasing fill) results indicated that anurans exhibited a strong nested pattern at both the sampling sites scale and the regional scale. The habitat matrix test results suggested that a small-scale study area requires a correspondingly small habitat-sampling extent to effectively test for habitat nestedness. As the study area expands, the habitat-sampling range can be appropriately increased. The nested pattern of anurans in the vicinity of Chengdu can only be explained by habitat nestedness, as a Spearman's correlation analysis showed that other environmental factors (area size, connectivity index, concentration index, proximity index, and distance to the city center) were not significantly correlated with the nested sequences of sampling points and regions. Therefore, regarding the conservation strategies for anurans in the vicinity of Chengdu, we recommend prioritizing the protection of areas with higher habitat diversity.

The ecological and evolutionary dynamics of inselbergs.

Islands are fundamental model systems in ecology, biogeography, and evolutionary biology. However, terrestrial islands, unlike their aquatic counterparts, have received comparatively less attention. Among these land islands, inselbergs (i.e. isolated rock outcrops with diverse lithologies and a modest topographical prominence) stand out as iconic examples distributed worldwide across global biomes. Due to their durable lithology, inselbergs change slowly, persisting for tens of millions of years. In this review, we propose a biological definition for inselbergs that captures three fundamental characteristics of inselbergs from the perspective of biota. These are old age, isolation and the presence of unique microhabitats that are rare or absent in the surrounding matrix, fostering distinct communities often with unique and endemic biota. We synthesise the state of the art and formulate a set of testable hypotheses to deepen our understanding of the origins and maintenance of diversity on inselbergs, which are increasingly exposed to anthropogenic threats. By offering different habitats compared to the surrounding habitat matrix (e.g. moist microhabitats in dryland landscapes and xeric environments in humid tropical landscapes), inselbergs may allow specific lineages to thrive beyond their typical geographical limits. Particularly in drylands and degraded landscapes, inselbergs may not just provide different habitats but also act as ecological refuges or evolutionary refugia by providing a wider range of potential microhabitats than the surrounding matrix, enhancing resilience and promoting regional biodiversity. The central role of the matrix ensures that the ecological and evolutionary dynamics of inselbergs differ from those of true islands such as oceanic islands. Given that inselberg biota coexist within a terrestrial matrix, interactions between inselberg and matrix populations impact each other significantly. Over evolutionary timescales, matrix species may contract to inselberg refugia, preserving lineages while cycles of isolation and reconnection may drive speciation via a species pump. Although inselberg biodiversity has been studied predominantly from an island biogeography perspective, we argue that depending on the spatial scale, habitat specificity and mobility of the organisms considered, a range of different theories and paradigms can help explain the biogeography and local distribution patterns of different taxonomic and functional groups of inselberg species.

Moderate anthropogenic impacts alter temporal niche without affecting spatial distribution of ocelots in the Amazon rainforest

AbstractThe Amazon rainforest faces escalating human disturbances such as logging, mining, agriculture, and urbanization, leading to the conversion of primary forest into matrix habitat. This transformation's impact on mesocarnivores, specifically ocelots (Leopardus pardalis), is still largely unknown. In 2021, we deployed camera traps across a 174 km2 study area in Las Piedras, Madre de Dios, Peru, containing mixed land use and protected forests. Utilizing kernel density functions, we compared temporal activity patterns and employed spatially explicit capture‐recapture (SECR) models to assess density, encounter probability, and movement by habitat and trail type, as well as sex. Of the 293 captures, we identified 39 ocelots (21 females, 18 males), estimating an average density of 31.46 (SE 5.15) individuals per 100 km2 with no significant difference between protected and mixed‐use areas. Baseline detection and movement varied by sex, with male and female home ranges estimated at 17.14 and 4.10 km2, respectively. Ocelot temporal activity patterns differed between the protected area and the mixed‐use area, with increased nocturnality in areas of higher human impact. Our SECR results highlight that matrix habitats can support ocelot populations, emphasizing the need for further research on ocelot demographics in human‐modified Amazon rainforest areas facing varying degrees of anthropogenic disturbance.Abstract in Spanish is available with online material.

Influence of canopy structural complexity on urban woodland butterfly species richness

AbstractAs urban land use expands, understanding the conservation of biodiversity in urban settings becomes increasingly important. Urban areas contain a wide range of remnant natural, semi-natural and anthropogenic woodlands but the biodiversity of these woodlands is not well studied. Urban woodlands are usually constrained in size and subject to management which may not be focused on promoting biodiversity. As a habitat of critical importance, the characteristics of urban woodlands need to be better understood to maximise their biodiversity within a limited footprint in the urban landscape. We used repeat line-transect surveys and rapid woodland structure habitat assessments to investigate the habitat associations of butterflies in ten woodland patches representing a range of sizes (between 1 and 40 ha), ages and woodland characteristics in the urban habitat matrix of Milton Keynes, UK. We found that ancient woodland sites supported every species detected, but the butterfly communities of amenity and roadside woodlands had similar species richness, diversity and abundance, regardless of size. Butterfly species richness was strongly associated with both woodland area and structural complexity at a site-scale, but only with structural complexity on a transect scale. Simpson diversity showed no correlation with any variable at the site scale, but strong correlation with structural complexity on transects. Abundance only correlated with area at the site scale. Our results suggest that management techniques that introduce structural complexity within urban woodlands may be an effective way to support butterfly richness and diversity in contexts where woodland areas cannot be increased.

Forest habitat loss and human land use alter predation of artificial ground nests

Anthropogenic disturbances including forestry, urbanisation and agricultural expansion are causing significant habitat loss and fragmentation in boreal forests, leading to changes in ecosystem function. Here, we ask whether these anthropogenic disturbances alter predator–prey spatial overlap in the boreal forest landscape, leading to increased nest predation rates on ground-nesting birds such as forest grouse. To study the roles of forest loss and fragmentation on nest survival, we conducted an artificial nest predation experiment in Finland using 370 camera traps across landscapes varying in forest quantity and fragmentation (measured by edge habitat length). Our artificial nests mimicked the early egg-laying stage of forest grouse. Our primary hypotheses were that nest survival is higher in landscapes with more continuous forest habitat and less edge habitat, and that predator communities differ based on the matrix habitat between the forests. Our findings revealed a negative association with forest cover and nest predation risk, but forest fragmentation, measured as edge length, had no detectable relationship with the nest predation risk. Additionally, nest predation risk depended on the matrix habitat types, with agricultural land and urban areas exhibiting higher predation rates than clearcuts exhibited. Furthermore, the number of predator species observed was positively associated with the level of urban area present. We found that the raccoon dog (Nyctereutes procyonoides), a rather novel invasive alien species, was the most common mammalian nest predator, indicating a change in the predator community. Our results highlight the possible impact of both forest loss and the presence of agricultural and urban areas in the landscape on avian nest survival in forest habitats. We conclude that forest loss may be a more important factor affecting nest predation risk than forest fragmentation.

Ocellated Turkey diets and feeding ecology in an agricultural-forest matrix habitat in Campeche, Mexico

Ocellated Turkey diets and feeding ecology in an agricultural-forest matrix habitat in Campeche, Mexico

Constraints on avian seed dispersal reduce potential for resilience in degraded tropical forests

Abstract Seed dispersal is fundamental to tropical forest resilience. Forest loss or degradation typically leads to defaunation, altering seed transfer dynamics and impairing the ability of forested habitats to regenerate or recover from perturbation. However, the extent of defaunation, and its likely impacts on the seed dispersers needed to restore highly degraded or clear‐felled areas, remains poorly understood in tropical forest landscapes. To quantify defaunation of seed‐dispersing birds, we used field survey data from 499 transects in three forested regions of Brazil, first comparing the observed assemblages with those predicted by geographic range maps, and then assessing habitat associations of frugivores across land cover gradients. We found that current bird assemblages have lower functional diversity (FD) than predicted by species range maps in Amazonia (4%–6%), with a greater reduction in FD (28%) for the Atlantic Forest, which has been more heavily deforested for a longer period. Direct measures of seed dispersal are difficult to obtain, so we focused on potential seed transfer inferred from shared species occurrence. Of 83 predominantly frugivorous bird species recorded in relatively intact forests, we show that 10% were absent from degraded forest, and 57% absent from the surrounding matrix of agricultural land covers, including many large‐gaped species. Of 112 frugivorous species using degraded forest, 47% were absent from matrix habitats. Overall, frugivores occurring in both intact forest and matrix habitats were outnumbered by (mostly small‐gaped) frugivores occurring in both degraded forest and matrix habitats (23 additional species; 64% higher diversity). These findings suggest that birds have the potential to disperse seeds from intact and degraded forest to adjacent cleared lands, but that direct seed transfer from intact forests is limited, particularly for large‐seeded trees. Degraded forests may play a vital role in supporting natural regeneration of small‐seeded tree species as well as providing a ‘stepping‐stone’ in the regeneration pathway for large‐seeded trees. We propose that both intact and degraded forests will support the restoration potential of tropical forest landscapes, and that bird‐assisted seed dispersal can be enhanced by maintaining buffer zones of degraded or secondary forests around remaining intact forest patches. Read the free Plain Language Summary for this article on the Journal blog.

Species–area relationships of plants and microbes are driven by different mechanisms in patchy grassland fragments

Abstract The island species–area relationship (SAR) describes how the number of species on an island varies with its area and provides important information about the maintenance of species diversity and how species might be lost as habitats are lost and fragmented. While the island SAR has been widely studied among macroorganisms, patterns for soil microbes have been less forthcoming, as have analyses of potential underlying mechanisms. We examined the SAR patterns of plants, soil fungi and bacteria among remnant grassland fragments isolated by degraded habitat matrix in a steppe grassland. As expected, we found that the total species richness of plants, fungi and bacteria in the entire fragment decreased with decreasing fragment area. However, the mechanisms differed among taxa. For plants, the lower diversity was most likely because of decreases in habitat quality and habitat heterogeneity on smaller fragments. For fungi, we found similar results, but also an important interaction with plant diversity, suggesting they were coupled via their functional associations. For bacteria, the lower diversity on smaller fragments primarily resulted from a sampling effect from the larger species pool, which outweighed the effect of higher habitat heterogeneity on smaller fragments. Synthesis: Our study highlights that fragmentation‐induced loss of diversity can have many different underlying mechanisms and that understanding these mechanisms can provide useful insights to project future biodiversity loss and conservation.

Frugivore-mediated seed dispersal in fragmented landscapes: Compositional and functional turnover from forest to matrix.

Seed dispersal by frugivores is a fundamental function for plant community dynamics in fragmented landscapes, where forest remnants are typically embedded in a matrix of anthropogenic habitats. Frugivores can mediate both connectivity among forest remnants and plant colonization of the matrix. However, it remains poorly understood how frugivore communities change from forest to matrix due to the loss or replacement of species with traits that are less advantageous in open habitats and whether such changes ultimately influence the composition and traits of dispersed plants via species interactions. Here, we close this gap by using a unique dataset of seed-dispersal networks that were sampled in forest patches and adjacent matrix habitats of seven fragmented landscapes across Europe. We found a similar diversity of frugivores, plants, and interactions contributing to seed dispersal in forest and matrix, but a high turnover (replacement) in all these components. The turnover of dispersed seeds was smaller than that of frugivore communities because different frugivore species provided complementary seed dispersal in forest and matrix. Importantly, the turnover involved functional changes toward larger and more mobile frugivores in the matrix, which dispersed taller, larger-seeded plants with later fruiting periods. Our study provides a trait-based understanding of frugivore-mediated seed dispersal through fragmented landscapes, uncovering nonrandom shifts that can have cascading consequences for the composition of regenerating plant communities. Our findings also highlight the importance of forest remnants and frugivore faunas for ecosystem resilience, demonstrating a high potential for passive forest restoration of unmanaged lands in the matrix.

Open areas associated with traditional agriculture promote functional connectivity among amphibian demes in Mediterranean agrosystems

ContextFunctional connectivity across fragmented habitat patches is essential for the conservation of animal populations in humanized landscapes. Given their low dispersal capacity, amphibians in the Mediterranean region are threatened by habitat fragmentation and loss due to changes in land use, including agricultural intensification.ObjectivesWe assessed patterns of functional connectivity of a Near Threatened Mediterranean amphibian, the sharp ribbed newt (Pleurodeles waltl), in an agricultural landscape matrix in NW Spain subject to different intensification regimes.MethodsWe sampled newts in 17 ponds embedded in a terrestrial habitat matrix dominated by agricultural land uses. Genome-wide molecular markers (1390 SNPs) were used to assess patterns of genetic diversity and gene flow among ponds. We tested the role of landscape features on functional connectivity using isolation by resistance models incorporating information on Normalized Difference Vegetation Index (NDVI) data.ResultsWe found low levels of genetic diversity in all sampled populations. Global FST estimates and cluster analyses revealed shallow but significant genetic structure in the study area, with NDVI-based resistance models showing that open areas (rainfed crops and grasslands) offer lower resistance to gene flow and thus promote functional connectivity among demes.ConclusionsOur study highlights the important role of landscape features, such as open areas resulting from traditional rainfed agriculture, in promoting functional connectivity between amphibian populations in Mediterranean agrosystems. Conservation policies must adopt a functional network strategy and protect groups of inter-connected temporary ponds across the traditional agricultural matrix to efficiently preserve their associated biotic communities.

Dietary and habitat specialization, eye size, clutch size, and aerial lifestyle predict avian fragmentation sensitivity in an Andean biodiversity hotpot

The fragmentation of tropical forests remains a major driver of avian biodiversity loss, particularly for insectivores, yet the mechanisms underlying area sensitivity remain poorly understood. Studies in lowland systems suggest that loss of food resources, changes to light microenvironments, increased nest predation, and dispersal limitation are possible mechanisms, but these are untested for montane tropical bird communities. In this study, we related avian functional traits to area sensitivity (quantified using beta estimates from a multi-species occupancy model) to test the above four hypotheses for a cloud forest bird community (both resident species and just resident insectivores) in the Colombian Western Andes. We found that species with more specialized diets and those that use the canopy and subcanopy (loss of food hypothesis), larger relative eye sizes (light microhabitat hypothesis), and larger clutch sizes (nest predation hypothesis) were significantly more area sensitive. By contrast, there was no support for the dispersal limitation hypothesis; instead, we found that insectivores with more pointed wing shapes, and more aerial lifestyles, were significantly more fragmentation sensitive. These results suggest that reduced vegetation structure, loss of late-successional plant species, and loss of epiphytic plants may reduce food availability in fragments. Similarly, the ability to tolerate higher light intensity near fragment edges, or when traversing matrix habitat, may be important for persistence in fragments and suggests that habitat configuration may be of special importance in fragmented Andean landscapes. Overall, a lack of information on foraging, movement, and breeding ecology complicates avian conservation in the Andes.

A Great Escape: resource availability and density‐dependence shape population dynamics along trailing range edges

Populations along geographical range limits are often exposed to unsuitable climate and low resource availability relative to core populations. As such, there has been a renewed focus on understanding the factors that determine range limits to better predict how species will respond to global change. Using recent theory on range limits and classical understanding of density dependence, we evaluated the influence of resource availability on the snowshoe hareLepus americanusalong its trailing range edge. We estimated variation in population density, habitat use, survival, and parasite loads to test the Great Escape Hypothesis (GEH), i.e. that density dependence determines, in part, a species' persistence along trailing edges. We found that variability in resource availability affected density and population fluctuations and led to trade‐offs in survival for snowshoe hare populations in the northeastern USA. Hares living in resource‐limited environments had lower and less variable population density, yet higher survival and lower parasitism compared to populations living in resource‐rich environments. We suggest that density‐dependent dynamics, elicited by resource availability, provide hares a unique survival advantage and partly explain persistence along their trailing edge. We hypothesize that this low‐density escape from predation and parasitism occurs for other prey species along trailing edges, but the extent to which it occurs is likely conditional on the quality of matrix habitat. Our work indicates that biotic factors play an important role in shaping species' trailing edges and more detailed examination of non‐climatic factors is warranted to better inform conservation and management decisions.

A multispecies corridor in a fragmented landscape: Evaluating effectiveness and identifying high-priority target areas.

While Misiones, Argentina contains one of the largest remnants of Upper Paraná Atlantic Forest ecoregion, one of the world's biodiversity hotspots, only ~50% of this native forest is protected. Each protected area is at risk of becoming an island of native forest surrounded by a matrix of altered habitats due to ongoing land conversion. In an effort to maximize long-term connectivity between existing protected areas, DeMatteo [1] used a multifaceted cost analysis to determine the optimal location for the region's first multispecies corridor using noninvasive data on jaguars (Panthera onca), pumas (Puma concolor), ocelots (Leopardus pardalis), southern tiger cats (Leopardus guttulus), and bush dogs (Speothos venaticus). This work builds on this framework by integrating new field data that broadens the scope of species-specific data across the region's heterogeneous landscape, which varies in vegetation, disturbance, human proximity, and protective status. In addition, two different land use layers are compared across the distributions of the five carnivores, the overlap in their independent distributions, and their relationship to the multispecies corridor. Interpretation of these land use data to species-specific habitat suitability goes beyond DeMatteo [1], with a subdivision of suitability into marginal and optimal areas. This refined scale allows a reanalysis of key areas in the multispecies corridor, where connectivity was previously defined as at highly-at-risk, allowing for a more directed development of management strategies. These analyses and their interpretation extend beyond northern-central Misiones, as the threats are not unique to this region. The need to develop management strategies that balance human-wildlife needs will continue to grow as humans expand their footprint. The techniques applied in this analysis provide a way to identify key areas that require specific management strategies, either through restoration, protection, or a combination of both.

Fragmentation disrupts microbial effects on native plant community productivity

Abstract Anthropogenic habitat fragmentation—the breaking up of natural landscapes—is a pervasive threat to biodiversity and ecosystem function world‐wide. Fragmentation results in a mosaic of remnant native habitat patches embedded in human‐modified habitat known as the ‘matrix’. By introducing novel environmental conditions in matrix habitats and reducing connectivity of native habitats, fragmentation can dramatically change how organisms experience their environment. The effects of fragmentation can be especially important in urban landscapes, which are expanding across the globe. Despite this surging threat and the importance of microbiomes for ecosystem services, we know very little about how fragmentation affects microbiomes and even less about their consequences for plant–microbe interactions in urban landscapes. By combining field surveys, microbiome sequencing and experimental mesocosms, we (1) investigated how microbial community diversity, composition and functional profiles differed between 15 native pine rockland fragments and the adjacent urban matrix habitat, (2) identified habitat attributes that explained significant variation in microbial diversity of native core habitat compared to urban matrix and (3) tested how changes in urbanized and low connectivity microbiomes affected plant community productivity. We found urban and native microbiomes differed substantively in diversity, composition and functional profiles, including symbiotic fungi decreasing 81% and pathogens increasing 327% in the urban matrix compared to native habitat. Furthermore, fungal diversity rapidly declined as native habitats became increasingly isolated, with ~50% of variation across the landscape explained by habitat connectivity alone. Interestingly, microbiomes from native habitats increased plant productivity by ~300% while urban matrix microbiomes had no effect, suggesting that urbanization may decouple beneficial plant–microbe interactions. In addition, microbial diversity within native habitats explained significant variation in plant community productivity, with higher productivity linked to more diverse microbiomes from more connected, larger fragments. Synthesis. Taken together, our study not only documents significant changes in microbial diversity, composition and functions in the urban matrix, but also supports that two aspects of habitat fragmentation—the introduction of a novel urban matrix and reduced habitat connectivity—disrupt microbial effects on plant community productivity, highlighting preservation of native microbiomes as critical for productivity in remnant fragments.

Occupancy models disentangle the drivers of avian urban avoidance in North America's largest urban forest

Urbanization dramatically modifies natural landscapes, fragments previously intact habitats, and is spreading rapidly, making it one of the leading causes of worldwide biodiversity decline. We studied the impact of urbanization on the occupancy of breeding birds in the Great Trinity Forest in Dallas, TX, the largest urban forest in the United States. The matrix of habitat surrounding the Great Trinity Forest varies from highly urbanized industrial landscapes to more rural areas. Between May 15th and July 15th of 2018, 2019, and 2020 we surveyed 404 5-ha plots for forest birds, recording 4274 observations representing 49 species. We used time-to-detection to model avian occupancy in 17 species while accounting for false absences. We found that the avian community responded to anthropogenic impacts of urbanization in the matrix in diverse ways. Urbanization intensity had the largest negative impact on avian occupancy and best explained observed patterns of urban avoidance from previous studies. Occupancy of species with low vocal frequency was negatively impacted by continuous anthropogenic noise from automobile traffic, while a broader group of species was negatively impacted by intermittent noise from airplane traffic. Occupancy exhibited both positive and negative responses to increased feral hog activity. To maintain diverse bird communities in forest fragments with a heavily urbanized matrix, it may be necessary to maintain large habitat tracts and mitigate for the indirect effects of the matrix like noise and invasive species.

The effect of habitat transformation on a twig epiphytic orchid: Evidence from population dynamics

The tropical Andean landscape has been dramatically transformed over the last century with remaining native forest limited to small fragments within a heterogeneous matrix of crops, cattle pastures, and urban environments. We aimed to explore the impact of habitat transformation on the population dynamics in an endemic twig epiphytic orchid located within the undisturbed forest and within modified matrix habitat in two regions with contrasting landscape structures: with a dominant shade coffee matrix and a dominant grassland matrix. Over 2 years, we surveyed 4,650 individuals of the Colombian endemic orchid, Rodriguezia granadensis. We undertook four post-breeding censuses in three sites in each region in both native forest and pasture sub-sites (12 sub-sites; 48 censuses in total), and constructed demographic transition matrices (n = 36). The transition probabilities were calculated using a Bayesian approach and population grow rates were evaluated using asymptotic models and elasticities using transient dynamics. Between regions, higher population growth rate and inertia (defined as the largest or smallest long-term population density with the same initial density distribution) was seen in the shade coffee-dominated landscape. Additionally, population growth rate and damping ratio was higher in forest compared with pasture, with lower convergence time for the forest subsites. These demographic patterns reveal the contrasting levels of population resilience of this orchid in different landscape structures with the more connected shade-coffee dominated landscape permitting some healthier populations with greater population growth and survival in forest than pasture. This study highlights that twig epiphyte colonization of isolated phorophytes in pastures should not be interpreted as a sign of a healthy population but as a temporal transitory period.

Habitat determinants of species occupancy and niche partitioning among sympatric owlets: the paradoxical role of agricultural lands for the endangered Forest Owlet, Athene blewitti

Species with highly restricted distributions are intriguing especially when they co-occur with similar and related species that are more widely distributed. They are also of conservation concern because of their restricted distributions and low population size. The Forest Owlet (<em>Athene blewitti</em>) is an endangered species endemic to the central Indian landscape that occurs in apparently unconnected pockets. Two other species of owlets, with wide distributions in India, Jungle Owlet (<em>Glaucidium radiatum</em>) and Spotted Owlet (<em>Athene brama</em>) co-occur with Forest Owlet. Understanding how species use the habitat matrix is central to prioritizing conservation action. We studied the three species across an extensive part of the predicted range of Forest Owlets through 350 surveys. Our results indicate that Jungle Owlet occupancy (ψ = 0.5896, SE = 0.08) was highest, followed by Forest Owlet (ψ = 0.2517, SE = 0.10), and Spotted Owlet (ψ = 0.1781, SE = 0.07). The Forest Owlet showed a preference for stands of forests with large trees but not necessarily with closed canopies, as well as open habitats (agricultural land cover). The Spotted Owlet showed a preference for agricultural land cover with lower litter and bare ground cover. In contrast, the Jungle Owlet showed a preference for dense forest and canopy cover. The preference for agricultural cover by the Forest Owlet provides important insights into our understanding of the ecology of this owlet. Most significantly, it brings up several conservation challenges for managing this endangered species across a human-use landscape.

Testing the concept of edaphism for the quartz island flora of the Knersvlakte, South Africa

• Plant-functional traits are useful to study floras on unusual soils. • Quartz island flora, traits and environment differ from the surrounding. • Taxonomic, functional and edaphic diversity are high on quartz islands. • The flora of unusual edaphic habitats is worthy of particular protection. Edaphically unusual sites harbor a flora that is often unique in its taxonomic as well as functional composition and contain many endemic species. While this edaphic endemism, edaphism, has been discussed previously on various special soils, in this study we relate it for the first time to the floristic characteristics of so called “quartz islands”, edaphically driven special habitats in South Africa, and their surroundings (matrix habitat). We sampled the vegetation and soil for 245 vegetation plots in the Knersvlakte Nature Reserve and examined 336 plant species with respect to their evolutionary (plant family, habitat specificity), biogeographical (distributional range) as well as functional traits (life form, leaf succulence, flowering onset, dispersal mode). Based on the floristic uniqueness of the quartz islands, we expect them to host a highly specialized and locally endemic flora with smaller life forms, pronounced leaf succulence (both indicative of resource-conservative economics) and distinct reproductive traits than their surroundings. We find that, compared to the matrix habitat, quartz islands have significantly higher salinity and lower soil pH, and show higher proportion of leaf-succulent species of smaller life forms – some of which are restricted to quartz islands and have different timing of flowering onset, while dispersal via zoochory is less important. Like other special soils, quartz islands harbor unique plant species, which are distinguished by distinct trait patterns. We conclude that the concept of edaphism can be applied to quartz islands.

Accounting for predator species identity reveals variable relationships between nest predation rate and habitat in a temperate forest songbird.

Nest predation is the primary cause of nest failure in most ground‐nesting bird species. Investigations of relationships between nest predation rate and habitat usually pool different predator species. However, such relationships likely depend on the specific predator involved, partly because habitat requirements vary among predator species. Pooling may therefore impair our ability to identify conservation‐relevant relationships between nest predation rate and habitat. We investigated predator‐specific nest predation rates in the forest‐dependent, ground‐nesting wood warbler Phylloscopus sibilatrix in relation to forest area and forest edge complexity at two spatial scales and to the composition of the adjacent habitat matrix. We used camera traps at 559 nests to identify nest predators in five study regions across Europe. When analyzing predation data pooled across predator species, nest predation rate was positively related to forest area at the local scale (1000 m around nest), and higher where proportion of grassland in the adjacent habitat matrix was high but arable land low. Analyses by each predator species revealed variable relationships between nest predation rates and habitat. At the local scale, nest predation by most predators was higher where forest area was large. At the landscape scale (10,000 m around nest), nest predation by buzzards Buteo buteo was high where forest area was small. Predation by pine martens Martes martes was high where edge complexity at the landscape scale was high. Predation by badgers Meles meles was high where the matrix had much grassland but little arable land. Our results suggest that relationships between nest predation rates and habitat can depend on the predator species involved and may differ from analyses disregarding predator identity. Predator‐specific nest predation rates, and their relationships to habitat at different spatial scales, should be considered when assessing the impact of habitat change on avian nesting success.

Edge effect on vascular epiphytes in a subtropical Atlantic Forest fragment

Epiphytes are efficient indicators of environmental quality. The Atlantic Forest is a hotspot for epiphyte richness; however, it is experiencing one of the highest rates of degradation, exposing epiphytes to edge effects. This study aimed to evaluate the floristic composition and richness of vascular epiphytes and their relationship with phorophyte features and microenvironmental variables at the edge and in the interior of a subtropical Atlantic Forest fragment in Brazil. Twenty-five trees were analyzed, respectively, at the edge and in the interior of the fragment. Height and diameter of phorophytes, temperature, relative air humidity, photosynthetically active radiation and canopy opening were measured. A total of 41 epiphytic species were recorded, 40 occurring in the interior and 23 at the edge. Orchidaceae, Bromeliaceae, and Polypodiaceae were the richest families, representing 75% of all species. The average number of species per tree in the interior was twice that for the edge. Pleopeltis pleopeltifolia, Microgramma squamulosa, M. vacciniifolia and Rhipsalis teres concentrated great biomass in both environments, with twice as much in the interior. Epiphyte richness and biomass was lower on thinner trees with more open canopies at the edge. Our results indicate that the forest interior is more beneficial for epiphytes, which are sensitive to environmental changes caused by the edge effect. The contrast between the epiphytic communities of the edge and the interior reveals the need to increase richness and abundance of native trees and prevent cattle grazing, the planting of exotic species and more human settlements in the habitat matrix.