Habitat Heterogeneity Research Articles

Remote sensing reveals the role of forage quality and quantity for summer habitat use in red deer

BackgroundThe habitat use of wild ungulates is determined by forage availability, but also the avoidance of predation and human disturbance. They should apply foraging strategies that provide the most energy at the lowest cost. However, due to data limitations at the scale of movement trajectories, it is not clear to what extent even well-studied species such as red deer (Cervus elaphus) trade-off between forage quality and quantity, especially in heterogeneous alpine habitats characterized by short vegetation periods.MethodsWe used remote sensing data to derive spatially continuous forage quality and quantity information. To predict relative nitrogen (i.e. forage quality) and biomass (i.e. forage quantity), we related field data to predictor variables derived from Sentinel-2 satellite data. In particular, our approach employed random forest regression algorithms, integrating various remote sensing variables such as reflectance values, vegetation indices and optical traits derived from a radiative transfer model. We combined these forage characteristics with variables representing human activity, and applied integrated step selection functions to estimate sex-specific summer habitat selection of red deer in open habitats within and around the Swiss National Park, an alpine Strict Nature Reserve.ResultsThe combination of vegetation indices and optical traits greatly improved predictive power in both the biomass (R2 = 0.60, Root mean square error (RMSE) = 88.55 g/m2) and relative nitrogen models (R2 = 0.34, RMSE = 0.28%). Both female and male red deer selected more strongly for biomass (estimate = 0.672 ± 0.059 SE for normalised values for females, and 0.507 ± 0.061 for males) than relative nitrogen (estimate = 0.124 ± 0.062 for females, and 0.161 ± 0.061 for males, respectively). Females showed higher levels of use of the Swiss National Park.ConclusionsRed deer in summer habitats select forage quantity over quality with little difference between sexes. Females respond more strongly to human activities and thus prefer the Swiss National Park. Our results demonstrate the capability of satellite data to estimate forage quality and quantity separately for movement ecology studies, going beyond the exclusive use of conventional vegetation indices.

A spatially-heterogeneous impact of fencing on the African swine fever wavefront in the Korean wild boar population

In October 2019, South Korea’s first case of African swine fever (ASF) was reported in wild boar in the north of the country. Despite the implementation of a 2300 km-long fencing strategy, the ASF wavefront continued to invade southward. Our study aimed to investigate the ASF wavefront dynamics in different regions of South Korea, as well as to assess the effectiveness of the fencing measures on ASF dispersal and wavefront velocity. From the nationwide wild boar surveillance system, we extracted 2661 cases, starting from 2 October 2019 (first detection) to 15 September 2022. The cases were categorised into four main spatiotemporal clusters. The average wavefront velocity over the four clusters was estimated at 0.52 km/week, with the cluster in the eastern part of the Korean peninsula exhibiting the fastest velocity (0.99 km/week) compared to the other clusters (0.44, 0.31, and 0.15 km/week). We hypothesise that these differences are related to different wild boar densities due to heterogeneous habitat suitability. We also found that fencing significantly impacted ASF dispersal in only two of the four main clusters, with no evidence that fencing slowed down the spread of the wavefront in any of the clusters. We argue that this heterogeneity might result from fencing locations being misaligned with the true (and unobserved) wavefront.

Paleoclimate Fluctuations Facilitate the Biogeographical History of Endemic Species of Freshwater Crabs in China via Cycles of Introgressive Hybridisation and Habitat Isolation

ABSTRACTAimThe impact of Pleistocene climate fluctuations on the biogeographical history of aquatic species has been a topic of enduring debate. This issue poses particular challenges for parapatric closely related species, especially those situated in transition zones where species assemblages occur between distinct zoogeographic boundaries.LocationEastern China.TaxonFive closely related Sinopotamon species and subspecies, S. shensiense, S. honanense, S. y. yangtsekiense, S. y. shanxianense, and S. y. tongbaiense.MethodsThese parapatric Sinopotamon species and subspecies, distributed along the boundary between the Palaearctic and Oriental realms in eastern China, offer an ideal model for addressing these challenges. We explored the biogeographic history of these species by conducting a comparative phylogeographic analysis using nine microsatellite loci and two mitochondrial DNA sequences, combined with morphological variation and fine‐tuned ecological niche modelling.ResultsOur phylogeographic analyses consistently revealed two well‐supported clades: clade A, for S. y. yangtsekiense, and clade B, which includes other species showing polyphyletic patterning and significant gene introgression. The Nanyang Basin and surrounding mountains regions (NBSM) was identified as a critical shared refuge and hybrid zone, facilitating interspecific introgression through at least two putative hybridisation events. During the Late Pleistocene glacial cycles, introgressive hybridisation of these species occurred in the NBSM, followed by rapid expansion and colonisation of heterogenous habitats during interglacial cycles, with dispersal corridors largely aligning with the local river system. In particular, the diffusion corridor of S. honanense significantly disrupted the continuous distribution of S. y. shanxianense and S. y. tongbaiense, indicating that S. honanense has replaced S. y. shanxianense and S. y. tongbaiense in the NYSM and caused a disruption in its distribution.Main ConclusionsThe biogeographic histories of the species in clade B are consistent with a mixing–isolation–mixing model, which suggests that populations experienced repeated introgressive hybridisation during glacial periods and regional habitat isolation during interglacial periods. Our findings represent a classic case of fine tracking biogeographical scenarios in parapatric species and provide unprecedented insights into the evolutionary radiation of the freshwater fauna that occupies zoogeographic boundaries.

Carnivorous sundews (Drosera rotundifolia) are more carnivorous in high‐light bog microhabitats that are not also nutrient‐rich

Abstract Carnivorous plants adapt to variations in nutrient availability and shade by altering investment in carnivory in response to different environmental conditions. It is not clear, however, how carnivorous plants might alter investment in carnivory in relation to habitat heterogeneity at small scales. We hypothesised that the carnivorous plant Drosera rotundifolia would alter investment in carnivory and the amount of plant nitrogen (N) derived from prey in response to differences in shade and nutrients between hummock and hollow microforms on patterned peatlands. We investigated D. rotundifolia growing on three peatlands in Northern Europe: Scotland, Sweden, and Finland where we expect microhabitat variability to differ between peatlands due to differences in the ratio of precipitation to evapotranspiration. We measured differences in the density of sticky leaf tentacles (investment in carnivory) and the proportion of plant N that was prey‐derived (%Ndfp) for plants growing on hummocks and hollows at each peatland. At the Finland site P:ET ratio was lowest (1.86), and root N availability was similar for hollows and hummocks. Here, tentacle density and %Ndfp were ~50% higher for plants on hollows than on the more shaded hummocks. At the Scotland site P:ET was highest (5.40), root N availability was lower for hummocks than for hollows, and hummocks were more shaded. Here, there was little difference in tentacle density and %Ndfp between plants growing on hummocks and hollows. The Sweden site was intermediate in terms of P:ET ratio (2.63), habitat heterogeneity, and carnivory. Our results are consistent with the predictions of an evolutionary cost–benefit model for plant carnivory in which the marginal benefits of carnivory decrease with increasing root nutrient availability and decreasing light. This model predicted carnivorous plant phenotypic variability at small scales in response to different extents of habitat heterogeneity at our three study sites. Our study demonstrates the capacity for a carnivorous plant species to vary investment in carnivory, adjusting the proportion of prey‐derived N, in response to small‐scale habitat heterogeneity. We suggest that as well as an adaptation to low‐nutrient conditions, carnivory may also provide a means for plants to adapt to and persist in heterogeneous habitats. Read the free Plain Language Summary for this article on the Journal blog.

Limited Microbial Contribution in Salt Lake Sediment and Water to Each Other’s Microbial Communities

Climate change and human activities have led to frequent exchanges of sedimentary and aquatic microorganisms in lakes. However, the ability of these microorganisms to survive in their respective habitats between saline lake sediment and water remains unclear. In this study, we investigated microbial sources and community composition and metabolic functions in sediments and water in Yuncheng Salt Lake using a combination of source tracking and Illumina MiSeq sequencing. The results showed that 0.10–8.47% of the microbial communities in the sediment came from the corresponding water bodies, while 0.12–10.78% of the sedimentary microorganisms contributed to the aquatic microbial populations, and the microbial contributions depended on the salinity difference between sediment and water. Habitat heterogeneity and salinity variations led to the differences in microbial diversity, community composition, and assembly between sediment and water communities. The assembly of sedimentary communities was mainly controlled by stochastic processes (>59%), whereas the assembly of aquatic communities was mainly controlled by deterministic processes (>88%). Furthermore, sediments had a higher potential for metabolic pathways related to specific biogeochemical functions than lake water. These results provide insights into the survival ability of microorganisms and the mechanisms of microbial community assembly under frequent exchange conditions in saline lakes.

Microbiome dynamics and functional profiles in deep-sea wood-fall micro-ecosystem: insights into drive pattern of community assembly, biogeochemical processes, and lignocellulose degradation.

Wood-fall micro-ecosystems contribute to biogeochemical processes in the oligotrophic deep ocean. However, the community assembly processes and biogeochemical functions of microbiomes in wood fall remain unclear. This study investigated the diversity, community structure, assembly processes, and functional profiles of bacteria and fungi in a deep-sea wood fall from the South China Sea using physicochemical indices, amplicon sequencing, and metagenomics. The results showed that distinct wood-fall contact surfaces exhibit habitat heterogeneity. The bacterial community of all contact surfaces and the fungal community of seawater contact surface (SWCS) were affected by homogeneous selection. In SWCS and transition region (TR), bacterial communities were influenced by dispersal limitation, whereas fungal communities were affected by homogenizing dispersal. The Venn diagram visualization revealed that the shared fungal community between SWCS and TR was dominated by Aspergillaceae. Additionally, the bacterial community demonstrated a higher genetic potential for sulfur, nitrogen, and methane metabolism than fungi. The sediment contact surface enriched modules were associated with dissimilatory sulfate reduction and methanogenesis, whereas the modules related to nitrate reduction exhibited enrichment characteristics in TR. Moreover, fungi showed a stronger potential for lignocellulase production compared to bacteria, with Microascaceae and Nectriaceae identified as potential contributors to lignocellulose degradation. These results indicate that environmental filtering and organism exchange levels regulated the microbial community assembly of wood fall. The biogeochemical cycling of sulfur, nitrogen, and methane was mainly driven by the bacterial community. Nevertheless, the terrestrial fungi Microascaceae and Nectriaceae might degrade lignocellulose via the combined action of multiple lignocellulases.IMPORTANCEThe presence and activity of microbial communities may play a crucial role in the biogeochemical cycle of deep-sea wood-fall micro-ecosystems. Previous studies on wood falls have focused on the microbiome diversity, community composition, and environmental impact, while few have investigated wood-fall micro-ecosystems by distinguishing among distinct contact surfaces. Our study investigated the microbiome dynamics and functional profiles of bacteria and fungi among distinct wood-fall contact surfaces. We found that the microbiome community assembly was regulated by environmental filtering and organism exchange levels. Bacteria drive the biogeochemical cycling of sulfur, nitrogen, and methane in wood fall through diverse metabolic pathways, whereas fungi are crucial for lignocellulose degradation. Ultimately, this study provides new insights into the driving pattern of community assembly, biogeochemical processes, and lignocellulose degradation in the microbiomes of deep-sea wood-fall micro-ecosystems, enhancing our comprehension of the ecological impacts of organic falls on deep-sea oligotrophic environments.

Riparian habitat quality and seasonality drives spatiotemporal habitat ecology of sympatric Asian otters in southern Western Ghats

IntroductionRiparian habitats in the Western Ghats are vital semi-terrestrial zones playing multi-functional roles in the conservation of freshwater species. In dynamic ecosystems, we have scant knowledge on the interactive role of season and local riparian habitat conditions in driving spatiotemporal habitat use of sympatric semi-aquatic mustelids.MethodologyWe conducted seasonal monitoring of 169-196 riverine segments (250 m) in 2020 and 2021 to measure the sign encounter rates of Asian small-clawed otter (SCL) and smooth-coated otter (SCO) and recorded 29 riparian habitat variables.ResultsOur self-organizing map algorithm characterized alarge multivariate habitat data into six habitat clusters representing a gradient of riparian habitat conditions. The random forest (RF) algorithm identified forest cover, water quality, and substratum as influential factors in high quality habitat. The low-quality habitat with low sign encounter rates or no evidence of otters had anthropized stream buffers, with high proportion of agriculture, weed cover and anthropogenic disturbance as influential factors predicted by the RF algorithm. SCO distribution was restricted to the higher-order streams in close proximity to hydro-power dams. SCL had a comparatively larger spatial distribution in the lower-order streams. Our study shows that rainfall plays a significant role in enhancing the hydrological flow in non-perennial streams and also improves the water quality parameters and the riparian habitat conditions. We found highly variable encounter rates of both species across seasons and habitat quality gradients, however, overall, their mean encounter rates increased with the habitat quality gradient.DiscussionOur findings showed that relating otter sign encounter rates with fine-scale riparian habitat quality was a useful and practical approach to monitor the sensitivity of sympatric semi-aquatic mustelids towards habitat conditions and simultaneously monitor the riparian ecosystem health, across seasons and years. The long-term persistence of sympatric Asian otters in the Bhavani-Noyyal river basin would depend on the availability of high-quality riparian habitat patches. Our findings emphasize the need to develop comprehensive riparian habitat management plans in the southern Western Ghats which involves restoration of fragmented riparian zones and maintenance of riparian habitat heterogeneity to facilitate freshwater connectivity and movements of sympatric otters.

Determinants of plant species richness along elevational gradients: insights with climate, energy and water–energy dynamics

BackgroundUnderstanding the patterns and processes of species distributions has long remained a central focus of biogeographical and ecological research. While the evidence for elevational patterns in species richness is widespread, our understanding of underlying causes and mechanisms remains limited. Therefore, this study aimed to entangle the influence of environmental variables on plant species richness along elevational gradients in the Western Himalayas.MethodsWe compiled elevational distribution for about 1150 vascular plants using the published literature and available database. The species richness was estimated in 100-m elevational bands using the range interpolation method. We used the generalised linear model and structural equation modelling (SEM) framework to identify the direct and indirect effects of climatic factors on species richness.ResultsOur results indicated that primary environmental correlates of species richness varied with elevational gradients. Climatic variables combined with energy and water availability were more important than the topographic heterogeneity. Further, the direct and interaction effects of climatic variables were more substantial than their indirect effects. The indirect effects of climate are more strongly mediated by water–energy dynamics than the energy alone.ConclusionsOverall, our findings emphasise the importance of considering direct effects and interactions among environmental variables while studying the underlying mechanisms governing elevational biodiversity gradients. Species richness appeared to be shaped by climatic tolerances rather than habitat heterogeneity at regional scales. This information can have implications for biodiversity dynamics under environmental change.

Assessing spider community structure and ecological dynamics across urban and natural environments

AbstractThis study explores the diversity and distribution of spider populations across urban and natural‐semi natural habitats in Gongju‐si, South Korea. This study aims to investigate the ecological dynamics of spider populations across different habitat types and assess their implications for urban planning, particularly in terms of maintaining biodiversity through habitat heterogeneity and informed urban development strategies. Employing methodologies such as sweeping, manual collection, and pit‐fall traps, the research identifies 128 spider species and evaluates alpha and beta diversity, nestedness, and species interactions using advanced statistical and ecological tools. The findings indicate significant variations in spider diversity across different habitats, with urban areas exhibiting notable biodiversity despite human influences. Natural habitats, especially forests, demonstrate higher biodiversity and more intricate species interactions. Nestedness analysis reveals distinct community structures across habitats, while association rule learning highlights complex interspecies relationships. The study underscores the importance of maintaining habitat heterogeneity and incorporating ecological principles in urban planning to support biodiversity. It offers valuable insights into the roles of various habitats in ecological networks, emphasizing the necessity for balanced urban development and effective conservation strategies.

Ecological indicators for restoration success: Development of fish diversity in a large restored floodplain over twelve years

The restoration of rivers and their floodplains is complex, requires substantial financial efforts, intensive stakeholder involvement and long recovery times, making the identification of appropriate ecological indicators for restoration success a key challenge. Herein, one of the largest floodplain restorations along the European Danube was repeatedly assessed over a 12-year period. Changes in the fish community composition in relation to chemical and morphological habitat variables were assessed in all three restored habitat types free-flowing rivers (RS), reconnected oxbows (OS), and small floodplain ponds (FP) which are only temporarily connected to the main stem Danube. Fish species composition of RS, OS, FP and the Danube differed significantly. Species numbers (34 detected in 2022) remained largely constant since the last monitoring in 2013, whereas abundance increased by 15%. Small-bodied target species with short generation times were able to establish populations comprising all size classes shortly after restoration, whilst large-bodied species needed a decade after the restoration for full demographic representation. Highly specialised species such as the rheophilic Chondrostoma nasus used restored RS only during the life stages spawning and juvenile growth. Restoration increased habitat heterogeneity and the initialized hydromorphological processes are still ongoing, supporting the high species diversity. The observed differences in colonization patterns can be explained by species-specific life histories, resulting in diverse short and long-term responses of different fish species and life stages following restoration. Consequently, a comprehensive assessment of restoration success only becomes possible if multiple fish species as ecological indicators are combined in a long-term monitoring.

Spatial Heterogeneity Affects the Spatial Distribution Patterns of Caragana tibetica Scrubs

Caragana tibetica is a common species in the shrub-encroached desert grasslands of Inner Mongolia, China. Studying its distribution and factors can improve our grasp of shrub-encroached grassland dynamics and aid in regional biodiversity conservation. This study examined eight C. tibetica communities using point pattern analysis to assess the spatial distribution pattern (SDP) and the influencing factors of C. tibetica scrubs. We also propose a new index, i.e., the degree of deviation index (DoDI), to quantify the SDP of scrubs. The results revealed the following: (1) The shrubland of C. tibetica in the study area showed aggregated distribution on the scale of 0–30 m. On the scale of 30–50 m, the degree of aggregation gradually weakened and random distribution appeared. (2) There was not a significant correlation between SDP and environmental factors; however, DoDI showed that habitat heterogeneity had a certain impact on C. tibetica in the study area. Our research indicates that spatial heterogeneity contributes to the SDP of shrub plants in the shrub-encroached grasslands of the Inner Mongolia Plateau, and the use of DoDI enhances the ability to quantify and isolate the role of spatial heterogeneity. This study helps to deepen the understanding of the mechanisms of shrub encroachment formation in grasslands.

Discriminating Seagrasses from Green Macroalgae in European Intertidal Areas Using High-Resolution Multispectral Drone Imagery

Coastal areas support seagrass meadows, which offer crucial ecosystem services, including erosion control and carbon sequestration. However, these areas are increasingly impacted by human activities, leading to habitat fragmentation and seagrass decline. In situ surveys, traditionally performed to monitor these ecosystems, face limitations on temporal and spatial coverage, particularly in intertidal zones, prompting the addition of satellite data within monitoring programs. Yet, satellite remote sensing can be limited by too coarse spatial and/or spectral resolutions, making it difficult to discriminate seagrass from other macrophytes in highly heterogeneous meadows. Drone (unmanned aerial vehicle—UAV) images at a very high spatial resolution offer a promising solution to address challenges related to spatial heterogeneity and the intrapixel mixture. This study focuses on using drone acquisitions with a ten spectral band sensor similar to that onboard Sentinel-2 for mapping intertidal macrophytes at low tide (i.e., during a period of emersion) and effectively discriminating between seagrass and green macroalgae. Nine drone flights were conducted at two different altitudes (12 m and 120 m) across heterogeneous intertidal European habitats in France and Portugal, providing multispectral reflectance observation at very high spatial resolution (8 mm and 80 mm, respectively). Taking advantage of their extremely high spatial resolution, the low altitude flights were used to train a Neural Network classifier to discriminate five taxonomic classes of intertidal vegetation: Magnoliopsida (Seagrass), Chlorophyceae (Green macroalgae), Phaeophyceae (Brown algae), Rhodophyceae (Red macroalgae), and benthic Bacillariophyceae (Benthic diatoms), and validated using concomitant field measurements. Classification of drone imagery resulted in an overall accuracy of 94% across all sites and images, covering a total area of 467,000 m2. The model exhibited an accuracy of 96.4% in identifying seagrass. In particular, seagrass and green algae can be discriminated. The very high spatial resolution of the drone data made it possible to assess the influence of spatial resolution on the classification outputs, showing a limited loss in seagrass detection up to about 10 m. Altogether, our findings suggest that the MultiSpectral Instrument (MSI) onboard Sentinel-2 offers a relevant trade-off between its spatial and spectral resolution, thus offering promising perspectives for satellite remote sensing of intertidal biodiversity over larger scales.

Can beavers canopy alterations affect managed forests more than natural forests?

Beavers, as ecosystem engineers, significantly affect riparian ecosystems, mostly through foraging and dams construction. This study examines how beaver-related tree cutting altered canopy openness and affected microhabitats and forest floor vegetation in the Northern Poland’s Tuchola Forest. Woody plant characteristics, forest floor vegetation abundance, and canopy openness were assessed at three sites varying in forest naturalness, with canopy openness being measured using hemispherical photography. Results show that selective tree removal by beavers from all diameter classes significantly increased canopy openness. This alteration leads to transformative changes in forest habitat properties, notably increasing light availability, and to nutrient status changes as evidenced by shifts in Ellenberg indicator values. Consequently, these changes result in increased forest floor total vegetation cover, diversity and composition. The cascading effects of beaver tree-cutting on canopy alterations have been comprehensively modelled using structural equation models. The study also reveals distinct spatial patterns in canopy alterations, with the most pronounced effects near riverbanks. The intensified impact of beaver activities, could be linked to the naturalness of the forest, and might be especially pronounced in more altered environments, particularly where pioneer aspen trees dominate the tree stand composition. These findings underscore the role of beavers in shaping forest dynamics, particularly in managed or disturbed forests. By creating canopy gaps, beavers initiate processes that enhance habitat heterogeneity and biodiversity, suggesting that their presence may be crucial for the restoration of natural processes in disturbed ecosystems.

Grassland bird responses to bison and prescribed fire in restored tallgrass prairies

AbstractGrazing from megaherbivores such as bison (Bison bison) and periodic fire are 2 important disturbance regimes in grassland ecosystems. In restored tallgrass prairies where these processes were previously removed, prescribed fire application and bison reintroduction are tools used by managers to recreate habitat heterogeneity formed by these disturbances. Tallgrass prairie bird communities may be indirectly affected by these disturbances, as bison and prescribed fire alter the structure of critical breeding habitat for grassland birds. The objectives of this research were to determine the effects of bison and prescribed fire on grassland breeding birds in 2 tallgrass prairie preserves in the Midwest region of the United States. We surveyed bird communities, vegetation structure, and bison activity at an Illinois preserve (n = 20 sites) and an Indiana preserve (n = 27 sites) in 2020 and 2021 and compiled a history of restoration activities (e.g., prescribed fire, planting year) at these sites. Grazing and fire disturbances affected grassland bird diversity and abundances, whereas we found little to no evidence that restoration planting age and spatiotemporal factors affected grassland bird populations. Disturbance effects often corresponded to species‐specific responses to changes in vegetation structure. Grassland‐obligate bird diversity was lower in recently burned and ungrazed management units, in comparison to unburned‐ungrazed and unburned‐grazed sites. Henslow's sparrow (Centronyx henslowii), a species known to be sensitive to recent prescribed fire, exhibited increased abundance with time since fire, an increase that was further amplified with bison presence. These results highlight the importance of applying varying levels of grazing and fire disturbance to provide variable vegetation structure to accommodate the habitat preferences of a diversity of grassland bird species. Moreover, our results indicate that bison may play a role in mediating the differing effects of variable prescribed fire frequencies on grassland bird species of concern.

Cross‐scale scaling‐law analyses for the heterogeneity and diversity of animal gut microbiomes from community to landscape

Diversity and heterogeneity often are conflated but are fundamentally different. An aphorism proposed by Shavit and Ellison (2021; J. Phil. 118: 525–548) for distinguishing them is that ‘a zoo is diverse whereas an ecosystem is heterogeneous.' That is, a zookeeper measuring diversity simply enumerates the different types of animals; interactions are not expected to occur between animals separated by fences or other barriers. In contrast, measures of heterogeneity ought to include both interspecific interactions and relationships between species and their heterogeneous habitats. Here, we use cross‐scale, dual scaling‐law analyses of heterogeneity and diversity of animal gut microbiomes (AGMs) to address three objectives: 1) estimate the spatial heterogeneity and diversity of animal‐gut microbiomes; 2) analyze influences of phylogeny and diets on scaling of diversity and heterogeneity; 3) explore mechanistic differences between diversity and heterogeneity in AGMs. From 4903 AGM samples collected from 318 animal species covering all six classes of vertebrates and four major classes of invertebrates, we estimated that ≈640 000 operational taxonomic units (OTUs or ‘species') make up the pool of microbial species that could inhabit animal guts, among which ≈8000 are relatively common and ≈800 are dominant. The gut of any single animal, however, includes only 0.01–0.5% of the total species pool. We applied Ma's diversity‐area relationship for scaling diversity, and extend Taylor's power law and Luna et al.'s (2020; Diversity 12: 86) interaction diversity for scaling heterogeneity. At the community scale, phylogeny significantly influenced heterogeneity, but diets did not. Phylogeny and diets had limited influence on diversity at both community and landscape scales. We demonstrated that diversity and heterogeneity measure two different properties. Further, differences in scaling of diversity and heterogeneity are a result of heterogeneity being primarily the result of evolved dispersal behavior and interspecific interactions, whereas diversity results from abundances controlled on ecological time scales.

Analysis of the Diversity of Corticolous Lichens Associated with Tree Trunks in the Understories of Four Tropical Dry Forests of the Atlántico Department in Colombia

Tropical dry forests (TDFs) are unique ecosystems with high biodiversity, including a rich variety of lichen species. Lichens are sensitive to environmental changes and can serve as bioindicators of ecosystem health. This study examined the diversity of lichen communities at four TDF sites in the Atlántico Department of Colombia. More than 700 tree lichen specimens were collected and identified at the four sites. A total of 135 species of lichens were identified, of which 19 are possibly undescribed. The most diverse sites were Usiacurí and Repelón, both protected areas with relatively well-preserved forests. The findings of this study demonstrate that the Atlántico TDFs host a large diversity of lichens, with a significant number of records of new species. The observed differences in species composition between sites highlight the importance of habitat heterogeneity and anthropogenic pressures on lichen communities. The results emphasize the need for conservation strategies to protect these ecologically valuable lichen communities within the Atlántico TDFs.

Tectonic and climatic controls on plant biodiversity in the Hengduan Mountains, China

Mountainous regions contain some of the most dynamic landscapes in the world and host a majority of the global biodiversity hotspots. The Hengduan Mountains, located at the syntax of Eurasia and India, have a complex geological history associated with the hyperdiverse assemblage of species. Tectonics and geomorphic and climate processes in the Hengduan Mountains may have jointly caused the emergence of high biodiversity. We propose three mechanisms that may promote high-level montane biodiversity: habitat creation, habitat disruption, and habitat oscillations. We mapped species richness patterns for seed plants and computed phylogenetic endemism across the entire Hengduan region. We developed a set of geomorphic metrics regarding these mechanisms to link plant richness and phylogenetic endemism patterns. By estimating the component of species richness due to habitat heterogeneity, we isolate the component due to tectono-geomorphic processes. We found that regions of exceptionally high species richness are explained by a combination of habitat heterogeneity and tectono-geomorphic processes, while glaciation and high climate change velocity are associated with low richness, thus contributing to recent extinction. We interpret the richness of biodiversity hotspots in the Hengduan Mountains in terms of climatic and tectonic processes.

Unraveling global species richness patterns of the Lysmatidae family: a multi-scale and multi-hypothesis ecological approach

While diversity gradients are well-explored in macroecology, factors shaping species richness at broad scales remain debated. We investigated the species richness of the decapod family Lysmatidae across 4 spatial scales: realm, province, ecoregion, and local (2° × 2° grid cells). We tested 4 ecological hypotheses: physiological stress (PSH), resource availability (RAH), habitat heterogeneity (HHH), and anthropogenic impact (AIH). Occurrence data (52 Lysmatidae species) and environmental variables (salinity, temperature, primary productivity, bathymetry, coral richness, anthropogenic impact index) were obtained from online databases and literature. Fifteen regression models, incorporating spatial filters, were tested to assess the hypotheses. The highest Lysmatidae species richness occurred in the Tropical Atlantic and Central Indo-Pacific realms. Richness varied with scale, with the highest values in the transition between the tropical and subtropical zones. Bathymetry was associated with Lysmatidae richness across all scales, especially at local and ecoregional scales, while coral richness was related to province and realm scales. HHH explained Lysmatidae richness patterns at the realm scale. Variables related to PSH and AIH were associated with richness at the ecoregion and province scales. Our study emphasized the importance of scale in biodiversity research, influencing richness patterns in Lysmatidae, and pointed to bathymetry, coral richness, and temperature range as the main drivers of richness. As this study showed a relationship between Lysmatidae richness, coral richness, and temperature at 3 spatial scales, this family may be susceptible to the effects of climate change, such as tropicalization of subtropical zones and defaunation of tropical ecosystems, including coral reefs.

Individual return patterns of spawning flannelmouth sucker (Catostomus latipinnis) to a desert river tributary

Tributaries provide temporal and spatial habitat heterogeneity in river networks that can be critical for parts of the life history of a species. Tributary fidelity can benefit individual fish undergoing spawning migrations by reducing time and energy spent exploring new areas and leveraging previous experience, but anthropogenic activities that fragment or degrade these systems can eliminate those benefits. We used multistate models based on passive integrated transponder (PIT) detection data from 2013 to 2023 to estimate the proportion of flannelmouth suckers (Catostomus latipinnis) migrating to a tributary, McElmo Creek, from the mainstem San Juan River for spawning. Survival varied among years and among states. The top model for migration probability included sex, with males slightly more likely to migrate (0.93 vs 0.90), and the next model identified interannual variation in migration probability ranging from 0.875 to 0.999 across years, indicating high site fidelity. Individuals showed consistency in relative arrival timing across years, with the highest correlation generally during years with greater spring discharge and extended tributary residence time. Successful tributary spawning may be important for the maintenance of the mainstem San Juan River flannelmouth sucker population, but site fidelity may be maladaptive where tributaries are vulnerable to human alterations.

Plant virus community structuring is shaped by habitat heterogeneity and traits for host plant resource utilisation.

Host plants provide resources critical to viruses and the spatial structuring of plant communities affects the niches available for colonisation and disease emergence. However, large gaps remain in the understanding of mechanisms that govern plant-virus disease ecology across heterogeneous plant assemblages. We combine high-throughput sequencing, network, and metacommunity approaches to test whether habitat heterogeneity in plant community composition corresponded with virus resource utilisation traits of transmission mode and host range. A majority of viruses exhibited habitat specificity, with communities connected by key generalist viruses and potential host reservoirs. There was an association between habitat heterogeneity and virus community structuring, and between virus community structuring and resource utilisation traits of host range and transmission. The relationship between virus species distributions and virus trait responses to habitat heterogeneity was scale-dependent, being stronger at finer (site) than larger (habitat) spatial scales. Results indicate that habitat heterogeneity has a part in plant virus community assembly, and virus community structuring corresponds to virus trait responses that vary with the scale of observation. Distinctions in virus communities caused by plant resource compartmentalisation can be used to track trait responses of viruses to hosts important in forecasting disease emergence.