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AIM: To investigate the performance and relative importance of abiotic and biotic predictors of species richness of three taxa in forest‐dominated landscapes across an environmentally heterogeneous mountain region. LOCATION: Switzerland (central Europe). METHODS: We used a broad set of nationally available environmental predictors grouped into (1) climate, (2) topography and soil and (3) 3‐D vegetation structure derived from airborne Light Detection and Ranging (LiDAR) data to spatially predict the forest species richness of vascular plants, butterflies and breeding birds. We used presence data of 212 plant, 157 butterfly and 92 bird species from multiple transect samples in > 220 1 km² squares at elevations between 261 and 2123 m a.s.l. across 41,248 km². We applied an ensemble modelling approach consisting of five modelling techniques and evaluated their predictive performance using the cross‐validated percentage of explained variance of each predictor group separately and the combinations thereof. We investigated the relative importance and response of each predictor and partitioned the variation into independent and shared components per variable group. RESULTS: Climate performed best in predicting forest species richness across taxa. Vegetation structure particularly improved the predictions of butterfly and bird species richness, while soil pH was an important predictor for forest plant species richness. Climate appeared to be mainly indirectly related to butterfly species richness, via correlations with habitat type and structure. The strength and direction of the relationships between the predictors and species richness were taxon‐specific with low cross‐taxon congruence. MAIN CONCLUSIONS: The growing availability of LiDAR data offers powerful new tools for describing vegetation structure and associated animal habitat quality across large areas. This will further our understanding of niche‐driven assembly processes in forest landscapes. Although climate was the dominant factor controlling species richness across taxa from different trophic levels, the taxon‐specific distributional pattern and response to environmental conditions emphasize the difficulty of accounting for a range of taxa in prioritising biodiversity conservation measures.

Determining how widespread human-induced changes such as habitat loss, landscape fragmentation, and climate instability affect populations, communities, and ecosystems is one of the most pressing environmental challenges. Critical to this challenge is understanding how these changes are affecting the movement abilities and dispersal trajectories of organisms and what role conservation planning can play in promoting movement among remaining fragments of suitable habitat. Whereas evidence is mounting for how conservation strategies such as corridors impact animal movement, virtually nothing is known for species dispersed by wind, which are often mistakenly assumed to not be limited by dispersal. Here, we combine mechanistic dispersal models, wind measurements, and seed releases in a large-scale experimental landscape to show that habitat corridors affect wind dynamics and seed dispersal by redirecting and bellowing airflow and by increasing the likelihood of seed uplift. Wind direction interacts with landscape orientation to determine when corridors provide connectivity. Our results predict positive impacts of connectivity and patch shape on species richness of wind-dispersed plants, which we empirically illustrate using 12 y of data from our experimental landscapes. We conclude that habitat fragmentation and corridors strongly impact the movement of wind-dispersed species, which has community-level consequences.

Predicting the effects of fire on biota is important for biodiversity conservation in fire-prone landscapes. Time since fire is often used to predict the occurrence of fauna, yet for many species, it is a surrogate variable and it is temporal change in resource availability to which animals actually respond. Therefore prediction of fire-fauna relationships will be uncertain if time since fire is not strongly related to resources. In this study, we used a space-for-time substitution across a large diverse landscape to investigate interrelationships between the occurrence of ground-dwelling mammals, time since fire, and structural resources. We predicted that much variation in habitat structure would remain unexplained by time since fire and that habitat structure would predict species' occurrence better than time since fire. In line with predictions, we found that time since fire was moderately correlated with habitat structure yet was a poor surrogate for mammal occurrence. Variables representing habitat structure were better predictors of occurrence than time since fire for all species considered. Our results suggest that time since fire is unlikely to be a useful surrogate for ground-dwelling mammals in heterogeneous landscapes. Faunal conservation in fire-prone landscapes will benefit from a combined understanding of fauna-resource relationships and the ways in which fire (including planned fires and wildfires) alters the spatial and temporal distribution of faunal resources.

Global biodiversity is increasingly threatened by land-use change, but the direct and indirect drivers of species diversity in human-modified tropical landscapes are poorly known. Forest-dependent species are expected to be particularly sensitive to changes in landscape composition (e.g., forest loss) and configuration (e.g., increase of forest edges), both directly and indirectly through cascading landscape effects on local patterns of forest structure and resource availability. In contrast, non-forest-dependent species are probably more strongly related to landscape changes than to local forest patterns, as these species are able to use resources not only from the forest, but also from other landscape elements over larger spatial scales. We tested these hypotheses using structural equation modeling. In particular, we sampled 20 landscapes (115 ha each) from the Brazilian Atlantic rainforest to assess the effect of landscape-scale forest cover and amount of forest edges on the diversity of frugivorous birds, both directly and indirectly through the effect that these landscape variables may have on vegetation complexity and fruit biomass. We separately assessed the response of forest-dependent and non-forest-dependent frugivores to infer potential mechanisms underlying bird assemblages in fragmented landscapes. The diversity of forest-dependent birds mainly decreased with the simplification of vegetation complexity in more deforested landscapes, but increased with increasing fruit biomass in more forested landscapes (indirect effects). Both patterns were significant, thus supporting a strong bottom-up control, i.e., local habitat simplification and resource scarcity in highly deforested landscapes limits the maintenance of forest-dependent birds. Conversely, but as expected, non-forest-dependent birds were more strongly and directly related to landscape-scale patterns. In particular, landscapes with higher forest edge amount showed higher bird species diversity, probably because the increasing length of ecotones and interspersion/juxtaposition of different habitat types in landscapes with more forest edges can increase resource availability and foraging efficiency of non-forest-dependent birds. As the seed dispersal services offered by forest-dependent species cannot be ecologically compensated for by the proliferation of non-forest-dependent species, preventing forest loss is imperative to maintain forest-dependent birds and forest regeneration in this vanishing biodiversity hotspot.

By providing food, living space and reducing biotic and abiotic stress, habitat‐formers support diverse communities. The characteristics that mediate their value to associated organisms, however, are not always clear. Traditional assessments of habitat‐former and associated community relationships use broad‐scale classifications to group habitat‐formers according to identity or gross morphology. Trait‐based approaches instead measure traits at the level of the individual and in doing so allow for predictions that are not constrained to taxonomic groups. By measuring at the level of the individual, trait‐based approaches have the potential to capture not only interspecific variability, but also the intraspecific variation that is often ignored by traditional approaches. Trait‐based approaches may therefore provide a novel way to link the characteristics of habitat‐formers to ecosystem functioning. Here we quantified inter‐ and intraspecific variation in six macroalgal species and tested the relative importance of morphological traits and species identity in predicting the abundance of associated fauna. All species of macroalgae displayed substantial intraspecific morphological variation. Morphological traits were more important than species identity in predicting epifaunal abundances. Total surface area was the most important trait when predicting total abundance per thallus, whilst mean frond length was the most important predictor for abundance per gram algal biomass. This suggests that traits that describe the quantity of available habitat were the most important predictors of community abundance, but the shape or architecture of the habitat also contributes to structuring these communities. Our results indicate that trait‐based approaches may be more useful than traditional species‐based approaches when predicting the abundances of fauna associated with habitat‐forming species. A free Plain Language Summary can be found within the Supporting Information of this article. A free Plain Language Summary can be found within the Supporting Information of this article.

Biodiversity is declining worldwide due to anthropogenic impacts, especially noxious for freshwater ecosystems, considering their close relationship with human activities. Damming is one of the most harmful human impacts that leads to the loss of several riverine fish through habitat loss or change. Herein, we aimed to assess the relationship between the composition of fish assemblages in reservoirs and the availability of littoral habitats, and whether these patterns differ between native and non-native species. Fish assemblages of fifteen reservoirs from up to downstream the Paraíba do Sul river basin were evaluated. Habitat availability was more important for native than for non-native species, after controlling for the influence of reservoir features. Local drivers were crucial for the occurrence of non-native species which thrived in the absence of complex habitats. Macrophytes seemed to play two key but quite antagonistic roles for fish species. They were positively related to native small characids, probably acting as shelter against predation, but they were also related to hypoxic conditions in eutrophic reservoirs. These findings stress the importance of preserving or restoring physically complex habitats as beneficial for native fish species through providing grounds for feeding (catfishes on leaves) and recruitment (juveniles of characids in macrophytes banks).

Understanding how megaherbivores incorporate habitat features into their foraging behavior is key toward understanding how herbivores shape the surrounding landscape. While the role of habitat structure has been studied within the context of predator–prey dynamics and grazing behavior in terrestrial systems, there is a limited understanding of how structure influences megaherbivore grazing in marine ecosystems. To investigate the response of megaherbivores (green turtles) to habitat features, we experimentally introduced structure at two spatial scales in a shallow seagrass meadow in The Bahamas. Turtle density increased 50-fold (to 311 turtles ha−1) in response to the structures, and turtles were mainly grazing and resting (low vigilance behavior). This resulted in a grazing patch exceeding the size of the experimental setup (242 m²), with reduced seagrass shoot density and aboveground biomass. After structure removal, turtle density decreased and vigilance increased (more browsing and shorter surfacing times), while seagrass within the patch partly recovered. Even at a small scale (9 m²), artificial structures altered turtle grazing behavior, resulting in grazing patches in 60% of the plots. Our results demonstrate that marine megaherbivores select habitat features as foraging sites, likely to be a predator refuge, resulting in heterogeneity in seagrass bed structure at the landscape scale.

Human activities degrade and fragment coastal marine habitats, reducing their structural complexity and making habitat edges a prevalent seascape feature. Though habitat edges frequently are implicated in reduced faunal survival and biodiversity, results of experiments on edge effects have been inconsistent, calling for a mechanistic approach to the study of edges that explicitly includes indirect and interactive effects of habitat alteration at multiple scales across biogeographic gradients. We used an experimental network spanning 17 eelgrass (Zostera marina) sites across the Atlantic and Pacific oceans and the Mediterranean Sea to determine (1) if eelgrass edges consistently increase faunal predation risk, (2) whether edge effects on predation risk are altered by habitat degradation (shoot thinning), and (3) whether variation in the strength of edge effects among sites can be explained by biogeographical variability in covarying eelgrass habitat features. Contrary to expectations, at most sites, predation risk for tethered crustaceans (crabs or shrimps) was lower along patch edges than in patch interiors, regardless of the extent of habitat degradation. However, the extent to which edges reduced predation risk, compared to the patch interior, was correlated with the extent to which edges supported higher eelgrass structural complexity and prey biomass compared to patch interiors. This suggests an indirect component to edge effects in which the impact of edge proximity on predation risk is mediated by the effect of edges on other key biotic factors. Our results suggest that studies on edge effects should consider structural characteristics of patch edges, which may vary geographically, and multiple ways that humans degrade habitats.

Abstract Aim Our objective was to assess the extent to which reference sites within the Caraça Sanctuary protect surface water quality and physical habitat structure. We expected that outside the Sanctuary, human pressures—such as urbanization, untreated domestic sewage discharge, and riparian deforestation—would result in poorer water quality and altered physical habitat structure. We hypothesized that the Caraça Sanctuary maintains streams with high physical habitat integrity and water quality. Methods Data were collected from 28 stream sites, including assessments of 22 physical habitat attributes and 12 water quality parameters. In addition, land use and land cover in the upstream microbasins were analyzed, and a rapid assessment protocol was applied at each site to evaluate riparian vegetation and physical habitat diversity. Principal Component Analysis (PCA) was used to identify the key variables explaining variation among sites and to distinguish those located within and outside the Sanctuary. Two PCA biplots were generated: one for the habitat structure data and another for the water quality data. Results The first two PCA axes explained 50% of the variability in physical habitat structure and 48% in water quality, with the latter most affected at sites near urban and mining areas. Conclusions The results indicate that the Caraça Sanctuary provides a valuable reference area for the upper Rio Doce basin.