Habitat Fragmentation Research Articles

Research on the coupled mechanism of landscape connectivity simulation by integrating multi‐level ecological security patterns and multi‐scenario simulation: A case study of the main urban area of Hangzhou

AbstractIn the context of rapid urbanization, protecting landscape connectivity has become an effective measure to mitigate habitat fragmentation and curb biodiversity decline. However, in the current research on simulating optimization processes, the ecological constraints often set are dispersed, isolated, and fixed. They fail to form a comprehensive protective spatial framework and struggle to align with the multifaceted objectives of future development. This study, taking the main urban area of Hangzhou, China as a case study and employing small mammals as indicator species, utilizes the PLUS model to predict the potential threats to landscape connectivity of biological habitats posed by artificial surface expansion from 2020 to 2035. It constructs a coupled mechanism that integrates multi‐level ecological security patterns (ESPs) and multi‐scenario simulation for landscape connectivity, successfully demonstrating the effectiveness of this mechanism in future landscape connectivity preservation. The results indicate that under the scenarios of business‐as‐usual (BAU), priority given to urban development (PUD), and priority given to ecological protection (PEP), the overall level of landscape connectivity in the main urban area of Hangzhou is projected to decrease by 18.42%, 7.02%, and 4.39% respectively from 2020 to 2035. The reduction in core area is estimated to be 9.08%, 7.85%, and 6.34%, respectively, while highly important patches are expected to decrease by 12.91%, 7.51%, and 5.86%, respectively. Both PEP and PUD scenarios effectively mitigate the degree of landscape connectivity disruption. This study provides valuable insights for the future optimization of landscape connectivity and contributes to biodiversity conservation efforts.

Same scenario, different scripts: Landscape genetics in two codistributed subterranean rodents of the genus Ctenomys

AbstractSubterranean rodents of the genus Ctenomys typically occupy fragmented habitats, many currently altered by anthropogenic development. These changes affect functional connectivity among individuals, reducing gene flow levels. This study assessed the functional connectivity of two sympatric species of subterranean rodents, Ctenomys australis and Ctenomys talarum, examining the impact of landscape changes on their population genetic structure at a fine spatial scale. We conducted a spatially continuous sampling over 12 km of coastline in Southeastern Buenos Aires Province, Argentina, genotyping 91 and 106 individuals of C. australis and C. talarum, respectively, using 10–12 microsatellite loci. We applied various spatial layers characterizing both species' habitats to evaluate the landscape configuration's effect on individual gene flow. We employed Bayesian genetic clustering methods to infer population structure levels. Ctenomys talarum showed greater structure than C. australis. NDVI temporal variation was the main factor influencing C. australis' genetic structure, whereas suitable habitat, linked to the current landscape configuration, was the most significant factor in shaping C. talarum's genetic structure. Differences in dispersal capacity and habitat specificity appear to have influenced the population genetic structures of these species. The results indicated varying sensitivities to landscape changes; temporal landscape variations primarily impacted C. australis' genetic connectivity, whereas for C. talarum, the current landscape configuration was more influential.

Assessing genetic diversity in critically endangered Chieniodendron hainanense populations within fragmented habitats in Hainan

Habitat fragmentation has led to a reduction in the geographic distribution of species, making small populations vulnerable to extinction due to environmental, demographic, and genetic factors. The wild plant Chieniodendron hainanense, a species with extremely small populations, is currently facing endangerment and thus requires urgent conservation efforts. Understanding its genetic diversity is essential for uncovering the underlying mechanisms of its vulnerability and for developing effective conservation strategies. In our study, we analyzed 35 specimens from six different populations of C. hainanense using genotyping-by-sequencing (GBS) and single nucleotide polymorphism (SNP) methodologies. Our findings indicate that C. hainanense has limited genetic diversity. The observed heterozygosity across the populations ranged from 10.79 to 14.55%, with an average of 13.15%. We categorized the six populations of C. hainanense into two distinct groups: (1) Diaoluoshan and Baishaling, and (2) Wuzhishan, Huishan, Bawangling, and Jianfengling. The genetic differentiation among these populations was found to be relatively weak. The observed loss of diversity is likely a result of the effects of natural selection.

Predicting future climate change impacts on the potential distribution of the black howler monkey (Alouatta pigra): an endangered arboreal primate.

Climate change is one of the main factors affecting biodiversity worldwide at an alarming rate. In addition to increases in global extreme weather events, melting of polar ice caps, and subsequent sea level rise, climate change might shift the geographic distribution of species. In recent years, interest in understanding the effects of climate change on species distribution has increased, including species which depend greatly on forest cover for survival, such as strictly arboreal primates. Here, we generate a series of species distribution models (SDMs) to evaluate future projections under different climate change scenarios on the distribution of the black howler monkey (Alouatta pigra), an endemic endangered primate species. Using SDMs, we assessed current and future projections of their potential distribution for three Social Economic Paths (SSPs) for the years 2030, 2050, 2070, and 2090. Specifically, we found that precipitation seasonality (BIO15, 30.8%), isothermality (BIO3, 25.4%), and mean diurnal range (BIO2, 19.7.%) are the main factors affecting A. pigra distribution. The future climate change models suggested a decrease in the potential distribution of A. pigra by projected scenarios (from - 1.23 to - 12.66%). The highly suitable area was the most affected above all in the more pessimist scenario most likely related to habitat fragmentation. Our study provides new insights into the potential future distribution and suitable habitats of Alouatta pigra. Such information could be used by local communities, governments, and non-governmental organizations for conservation planning of this primate species.

Wildlife Conservation on Private Land: A Social-Ecological Systems Study

As human activity accelerates the global crisis facing wildlife populations, private land conservation provides an example of wildlife management challenges in social-ecological systems. This study reports on the research phase of ‘WildTracker’ - a co-created citizen science project, involving 160 landholders across three Tasmanian regions. This was a transdisciplinary collaboration between an environmental organisation, university researchers, and local landholders. Focusing on mammal and bird species, the project integrated diverse data types and technologies: social surveys, quantitative ecology, motion sensor cameras, acoustic recorders, and advanced machine-learning analytics. An iterative analytical methodology encompassed Pearson and point-biserial correlation for interrelationships, Non-Metric Multidimensional Scaling (NMDS) for clustering, and Random Forest machine learning for variable importance and prediction. Taken together, these analyses revealed complex relationships between wildlife populations and a suite of ecological, socio-economic, and land management variables. Both site-scale habitat characteristics and landscape-scale vegetation patterns were useful predictors of mammal and bird activity, but these relationships were different for mammals and birds. Four focal mammal species showed variation in their response to ecological and land management drivers. Unexpectedly, threatened species, such as the eastern quoll (Dasyurus viverrinus), favoured locations where habitat was substantially modified by human activities. The research provides actionable insights for landowners, and highlights the importance of ‘messy,’ ecologically heterogeneous, mixed agricultural landscapes for wildlife conservation. The identification of thresholds in habitat fragmentation reinforced the importance of collaboration across private landscapes. Participatory research models such as WildTracker can complement efforts to address the wicked problem of wildlife conservation in the Anthropocene.

Genetic structure and diversity of semi-captive populations: the anomalous case of the Asian elephant

Wild species living in captivity are subject to loss of genetic diversity, inbreeding depression, and differentiation among populations. Only very few species have been under human care for centuries but have not been selectively bred, have free-ranging movements most of the time, and retain porous barriers to gene flow between wild and captive populations. Such captive populations are expected to retain high levels of genetic diversity and anthropogenic factors should result in a limited genetic differentiation from wild populations. Asian elephants have been trained and used by humans for at least 4000 years as war animals, mounts of kings and draught animals. In Myanmar and Laos, elephants are still being used for hauling timber in the forest while retaining traditional management practices including seasonal release, free mating and movement. However, habitat fragmentation, isolation and reduced gene flows are threatening both semi-captive and wild pools. We genotyped 167 semi-captive elephants from Laos and Myanmar using a panel of 11 microsatellite loci to estimate the genetic diversity and population structure. We found that elephants of both countries presented high levels of genetic diversity and a low degree of inbreeding, if any. This agrees with the expected high level of genetic diversity in semi-captive populations. We found a weak differentiation along a geographical gradient from southern Laos to northern Myanmar but no differentiation between wild-caught and captive-born pools. The potential value for conservation of a large population of semi-captive elephants has been recognized but the conservation community has yet to fully explore the potential role semi-captive elephants could play in maintaining gene flows.

The Relationship between the Edge Density of the Forest Fragments and the Tree Species Richness in the Detached Fragments of Kakamega Forest.

Purpose: The theoretical approach guiding this study was based on the Island Biogeography Theory. The purpose of this study was to assess the influence of the edge density of the forest fragments on tree species richness.
 Methodology: The study adopted a cross-sectional correlational research design. Proportionate random sampling was used. A sample of 30 plots each measuring 2m by 2m was established randomly in the fragments (0-200m from the edge towards the interior);Malava: Kisere: Ikuywa in that order for field sampling and measurements. Data was collected using tools such as measuring tapes,metre rule,GPS 64s Garmain and suunto inclinometer. A total of 39 species of trees were recorded from the three fragments with Funtumia africana being recorded as the most abundant species.
 Findings: The findings show 83%, 85%, and 92% variation of tree species richness in. Malava (r2 = 0.83), Kisere (r2 = 0.85) and Ikuywa (r2 = 0.92) in that order can be explained by the edge density of the fragments. The edge density also explained 87%, 94% and 94% variation of tree species relative abundance in Malava (r2 = 0.87), Kisere (r2 = 0.94) and Ikuywa (r2 = 0.94) in that order.
 Unique Contributor to Theory, Policy and Practice: It was concluded that tree species richness and tree species abundance in the detached portions of Kakamega forest were dominantly influenced by forest fragment total edge length and fragment edge density. For us to conserve more tree species we recommend maintenance of the total edge length of the fragments above 15km with edge density (3.413.79m\m2) in order to maintain high tree species richness and tree species relative abundance.

The drivers of plant turnover change across spatial scales in the Azores

Beta diversity patterns are essential for understanding how biological communities are structured. Geographical and environmental factors, as well as species dispersal ability, are important drivers of beta diversity, but their relative importance may vary across spatial scales. In this study, we evaluate whether beta diversity changes across geographical scales and analyse how different drivers affect turnover patterns of native seed plants in an oceanic archipelago, the Azores (Portugal). Using a 500 × 500 m resolution grid, we selected cells that are covered by one of the following habitats: native forest, naturalized vegetation and seminatural pastures. We calculated species turnover at three spatial scales: 1) between islands, 2) between cells within each island, and finally 3) between cells of each of the habitats of interest in each island. We then calculated the contribution of dispersal syndromes (endozoochory, epizoochory, hydrochory and anemochory) to turnover at each of the scales. Lastly, we assessed the relationship between geographical and climatic distances and habitat type with turnover. Turnover was higher at the smallest spatial scale, particularly in seminatural pastures, and decreased with increasing spatial scales, a pattern potentially associated with the historical fragmentation and current patchy distribution of native forest and seminatural habitats in the Azores. Dispersal syndromes and habitat type had a negligible effect on turnover at all scales. Geographical distance had a positive effect on turnover at all scales, increasing its importance with scale. The relationship between turnover and climatic distance was only significant at the intermediate and small scales in specific islands and habitats. Therefore, scale plays an important role at determining the effect of the drivers of turnover, in particular geographical and climatic distance. These results highlight the need to carefully select the scale of analysis when studying turnover patterns, as well as identifying the potential drivers associated with each spatial scale.

The Behavior of Sumatera Llourism (Nycticebus coucang) In The Capture Facilities, Primate Animal Study Center LPPM-IPB

Lorises are protected and endangered animals, according to the IUCN, because of poaching, habitat fragmentation, and illegal sales that occur. This study aims to determine the suitability of the cages by observing the behavior and use of the cages space by the sumatera lorises in Primate Animal Study Center. The method used is instantaneous vocal animal sampling with 10-minute intervals. The study results showed locomotion behavior at 46.69%, social behavior at 2.63%, elimination at 1.6%, rest at 25.11%, grooming at 6.16%, foraging at 2.4%, eating at 3.88%, and being alert at 11.53%. Lorises in Primate Animal Study Center use the entire cages space provided to carry out active and inactive activities. The conservation aspect is sufficiently supportive of the housing and feed aspects provided. Even though the feed given is not in accordance with its original habitat, therefore a change in the feed menu is necessary.

Functional Groups of Terrestrial Invertebrates in the Leaf Litter of Atlantic Forest (Bahia, Brazil)

The study conducted in a native fragment of the Atlantic Forest in Alagoinhas, Bahia, Brazil, aimed to evaluate the action of functional groups of terrestrial invertebrates and the effect of seasonality on their biodiversity. Over 6 months, researchers captured 166 invertebrates representing 9 orders and 17 families. The findings revealed a greater abundance of invertebrates (77) at the edge of the forest fragment. However, the indices of diversity, equity, and richness were similar between the fragment's edge and interior. Notably, at the edge, detritivores (such as little armadillos) and predators (including ants and spiders) exhibited dominance over other functional groups like phytophagous, saprophagous, coprophagous, and bioturbators. Predators of the orders Hymenoptera and Araneae were highlighted for their ecological importance, particularly in biological control, especially of detritivores. Interestingly, the study did not observe the effect of seasonality during the brief inventory period. This suggests that other factors may significantly influence the biodiversity of terrestrial invertebrates in the Atlantic Forest fragment in Bahia, Brazil.

High genetic diversity but limited gene flow in Flemish populations of the crested newt, Triturus cristatus

Habitat destruction and fragmentation are among the major causes of amphibian decline. We investigated to what extent geographic distance and barriers affect the genetic composition of the crested newt, Triturus cristatus in Flanders (North Belgium), causing inbreeding or loss of genetic diversity. Data from seven microsatellite loci and 170 individuals from seven metapopulations up to 180km apart revealed heterozygosities of 0.53 to 0.67 within populations and moderate levels of genetic divergence between populations (FST values from 0.074 to 0.141, harmonic means of Dest between 0.070 and 0.189). In all Flemish meta-populations, more than 90% of the individuals from a given geographic region were assigned to the same genetic cluster indicating
 little genetic exchange, even in De Panne where the two populations Oosthoek and Westhoek are only a few kilometres apart. Such sub-structuring on a micro-scale has also been described in other amphibians. Unique alleles in most populations further support the probability that genetic drift has already led to some isolation. With the exception of the Oosthoek population, however, we found no significant evidence for bottlenecks. Connectivity within pool clusters seems essential to the maintenance of genetic diversity in crested newts as is indicated by our findings from Tommelen, the population with the largest number of pools in close proximity, which also shows the highest levels of heterozygosity (He and Ho) and the second highest number and richness of alleles. In conclusion, our study indicates that dispersal and migration rates between the Flemish populations of Triturus cristatus are limited at the geographic scale studied here but that habitat fragmentation has not yet led to a significant loss of genetic diversity of the studied Flemish populations, possibly because crested newts are relatively long-lived, fragmentation of their habitat is relatively recent in Flanders, and most investigated pools are still connected at the local scale.

Crop monitoring using remote sensing land use and land change data: Comparative analysis of deep learning methods using pre-trained CNN models

In the context of the rapidly evolving climate dynamics of the early twenty-first century, the interplay between climate change and biospheric integrity is becoming increasingly critical. The pervasive impact of climate change on ecosystems is manifested not only through alterations in average environmental conditions and their variability but also through ancillary shifts such as escalated oceanic acidification and heightened atmospheric CO2 levels. These climatic transformations are further compounded by concurrent ecological stressors, including habitat degradation, defaunation, and fragmentation. Against this backdrop, this study delves into the efficacy of advanced deep learning methodologies for the classification of land cover from satellite imagery, with a particular emphasis on agricultural crop monitoring. The study leverages state-of-the-art pre-trained Convolutional Neural Network (CNN) architectures, namely VGG16, MobileNetV2, DenseNet121, and ResNet50, selected for their architectural sophistication and proven competence in image recognition domains. The research framework encompasses a comprehensive data preparation phase incorporating augmentation techniques, a thorough exploratory data analysis to pinpoint and address class imbalances through the computation of class weights, and the strategic fine-tuning of CNN architectures with tailored classification layers to suit the specificities of land cover classification challenges. The models' performance was rigorously evaluated against benchmarks of accuracy and loss, both during the training phase and on validation datasets, with preventative strategies against overfitting, such as early stopping and adaptive learning rate modifications, being integral to the methodology. The findings illuminate the considerable potential of leveraging pre-trained deep learning models for remote sensing in agriculture, demonstrating that advanced CNN architectures, particularly DenseNet121 and ResNet50, are notably effective in enhancing crop type classification accuracy from satellite imagery. This study contributes valuable insights to the field of precision agriculture, advocating for the integration of sophisticated image recognition technologies to bolster crop monitoring efficacy, thereby enabling more nuanced agricultural decision-making and resource allocation.

Edge effects of a fragmented seagrass habitat on flow, bivalve recruitment, and sediment dynamics

In both continuous and fragmented seagrass ecosystems, the vegetation edge can be a location of abrupt hydrodynamic change, with impacts to both ecological and physical processes. We address how flow and wave activity change across seagrass meadow edges and the effects of vegetation on sediment dynamics and bivalve recruitment. Two Zostera marina seagrass meadow sites were monitored: a high-density site with >500 shoots m-2 and a low-density site with <250 shoots m-2. Mean flow velocities were significantly reduced in seagrass vegetation adjacent to edges, with reductions compared to unvegetated areas ranging from 30-75%. Recruitment of juvenile bivalves was significantly elevated within vegetation. No significant differences in wave activity or sediment suspension and/or deposition were found spatially across a 10 m distance from a seagrass edge, but significant temporal variability was observed, caused by periodic storms. Wave height was a major predictor for sediment movement along seagrass edges, with an observed 10-fold increase in sediment collection within benthic traps following severe storms. These results were found across various heterogeneous edge configurations and reveal abrupt hydrodynamic responses of both mean flow and turbulence to occur at short spatial scales (1-10 m), with changes to wave and sediment deposition and/or suspension conditions only occurring over larger spatial distances (~100 m). Changes to the hydrodynamic regime were therefore found to be driven by meteorological conditions (e.g. winds, storms) on daily timescales and by changes in seagrass shoot density, altering both bivalve recruitment and sediment dynamics on longer temporal and/or spatial timescales.

Estimation of the Leaf Area Index and Light Intensity in a Brazilian Tropical Forest Fragment

In order to apply techniques aimed at the restoration and recovery of forest fragments, it is necessary to understand the ecological succession of the respective biome and the factors influencing its dynamics. Luminosity is one of the key factors for comprehending the cycle of native forests, influenced not only by climatic seasonality but also by the canopy structure and forest strata. The Leaf Area Index (LAI) is directly linked to plant growth conditions. The objective of this study is to map the distribution of LAI in the canopy of a Mixed Ombrophilous Forest fragment using non-destructive methods and to quantify luminosity. The research was conducted around the University Campus of the State University of the Midwest - UNICENTRO, in the municipality of Irati, Paraná, Brazil. These variables underwent numerical terrain modeling using the free software SPRING, resulting in two spatial representations, each containing four classes for each variable. The data underwent statistical analysis using Spearman's and Pearson's correlations, resulting in coefficients of 0.89 and 0.9, respectively. Thus, both variables are strongly linked, with LAI as the independent variable and luminosity as the dependent variable. The use of numerical terrain modeling for the variables proved appropriate, as it allowed the expression of visual features that can be observed within the experimental area.

Estimation of the Leaf Area Index and Light Intensity in a Brazilian Tropical Forest Fragment

In order to apply techniques aimed at the restoration and recovery of forest fragments, it is necessary to understand the ecological succession of the respective biome and the factors influencing its dynamics. Luminosity is one of the key factors for comprehending the cycle of native forests, influenced not only by climatic seasonality but also by the canopy structure and forest strata. The Leaf Area Index (LAI) is directly linked to plant growth conditions. The objective of this study is to map the distribution of LAI in the canopy of a Mixed Ombrophilous Forest fragment using non-destructive methods and to quantify luminosity. The research was conducted around the University Campus of the State University of the Midwest - UNICENTRO, in the municipality of Irati, Paraná, Brazil. These variables underwent numerical terrain modeling using the free software SPRING, resulting in two spatial representations, each containing four classes for each variable. The data underwent statistical analysis using Spearman's and Pearson's correlations, resulting in coefficients of 0.89 and 0.9, respectively. Thus, both variables are strongly linked, with LAI as the independent variable and luminosity as the dependent variable. The use of numerical terrain modeling for the variables proved appropriate, as it allowed the expression of visual features that can be observed within the experimental area.

Spatiotemporal distribution and population trends of Sindh ibex (Capra aegagrus blythii) in Balochistan during 2019–2022

The increased pressures generated by human activities in form of climate change and habitat fragmentation have caused serious threats for Sindh ibex (Capra aegagrus blythii). Balochistan, recognized as one of the most vulnerable regions to climate change in Pakistan, has limited data on the distribution and population status of this species. To address this gap, our study aims to assess the spatial and temporal distribution and population trend of Sindh ibex in the Khuzdar and Lasbela districts of Balochistan. The study covered an area of approximately 45,123.97 km2. It involved a double-observer survey at ten sites from 2019 to 2022, using the BBRecapture package in the R programming language to estimate ibex population trend and dispersion. We provided a comprehensive update of the species geographic range, along with estimates of its current abundance and population trends. Over the course of four years, the ibex population fluctuated. The ibexes detected dropped from 720 (male to female ratio 1:1.21) and 710 (male to female ratio 1:1.08) in 2019 and 2020, respectively, to 550 (male to female ratio 1:1.35) and 548 (male to female ratio 1:1.09). Overall, this study provides valuable insights into the population trends, gender ratios, habitat preferences, and density of Sindh ibex in Balochistan over the four-year period. These findings contribute significantly to the baseline data on the species ecology and will further help in the conservation of these species at local scale.

Genetic diversity and population structure of the endangered saproxylic beetle L. cervus in a fragmented landscape

Abstract Despite the significance of saproxylic beetle species for ecosystems, the investigation of fine‐scale population genetics within the stag beetle, Lucanus cervus, remains notably limited. Because of their limited dispersal distances and habitat fragmentation, high genetic structure and low genetic diversity are expected in its populations. To evaluate the impact of habitat fragmentation on genetic diversity and structure, we examined 150 specimens of L. cervus from three sites in western Poland: two forest stands and one stand located in an Oak avenue. We utilised 19 microsatellite DNA loci for this examination. Results of neighbour‐joining analysis and principal coordinates analysis, values of differentiation indexes (G'ST, D(Jost) and FST) and rare/private allele frequencies indicated weak genetic differentiation among individuals collected from the tree sites. A spatial component to the genetic structure was identified through STRUCTURE (LOCPRIOR), isolation by distance tests and spatial autocorrelation analysis. The genetic diversity remained relatively high (HE: 0.49–0.51), with no inbreeding observed and no significant differences in mean relatedness among individuals from sampling sites. Limited genetic differentiation between the individuals of L. cervus from the investigated sites may result from a lag time since fragment isolation, unrestricted gene flow and marker/sample size limitations. Though weak, the significant differentiation between two of the sites may be linked to environmental differences and distance. Genetic data support treating individuals from forests as a single management unit. Non‐invasive sampling suffices for genetic studies, but achieving balanced sampling is crucial for precise historical demography estimates of endangered species.

Phylogeography of the freshwater crab Potamon persicum (Decapoda: Potamidae): an ancestral ring species?

The Zagros Mountains, characterized by complex topography and three large drainage systems, harbor the endemic freshwater crab Potamon persicum in Iran. Our study delves into the evolutionary history of P. persicum, utilizing two mitochondrial and one nuclear marker. We collected 214 specimens from 24 localities, identifying 21 haplotypes grouped into two major evolutionary lineages. Substantial differentiation exists between drainage systems and lineages. Historical demographic analysis revealed a significant decrease in population size during the late Holocene, accompanied by a recent population bottleneck. Species distribution modeling has revealed eastward shifts in suitable habitats between the last glacial maximum and the present day. Following the last glacial maximum, habitat fragmentation occurred, resulting in the establishment of small populations. These smaller populations are more vulnerable to climatic and geological events, thereby limiting gene flow and accelerating genetic differentiation within species. Historical biogeographic analysis traced the origin of P. persicum to the western Zagros Mountains, with major genetic divergence occurring during the Pleistocene. Our genetic analyses suggest that P. persicum may have shown a genetic pattern similar to a classical ring species before the Pleistocene. The Namak Lake sub-basin could have served as a contact zone where populations did not interbreed but were connected through gene flow in a geographic ring. Currently, genetic separation is evident between basins, indicating that P. persicum in the Zagros Mountains is not a contemporary ring species. Also, our biogeographical analysis estimated that range evolution may have been driven initially by dispersal, and only during the late Pleistocene by vicariance.

Habitat loss weakens the positive relationship between grassland plant richness and above-ground biomass.

Habitat loss and fragmentation per se have been shown to be a major threat to global biodiversity and ecosystem function. However, little is known about how habitat loss and fragmentation per se alters the relationship between biodiversity and ecosystem function (BEF relationship) in the natural landscape context. Based on 130 landscapes identified by a stratified random sampling in the agro-pastoral ecotone of northern China, we investigated the effects of landscape context (habitat loss and fragmentation per se) on plant richness, above-ground biomass, and the relationship between them in grassland communities using a structural equation model. We found that habitat loss directly decreased plant richness and hence decreased above-ground biomass, while fragmentation per se directly increased plant richness and hence increased above-ground biomass. Fragmentation per se also directly decreased soil water content and hence decreased above-ground biomass. Meanwhile, habitat loss decreased the magnitude of the positive relationship between plant richness and above-ground biomass by reducing the percentage of grassland specialists in the community, while fragmentation per se had no significant modulating effect on this relationship. These results demonstrate that habitat loss and fragmentation per se have inconsistent effects on BEF, with the BEF relationship being modulated by landscape context. Our findings emphasise that habitat loss rather than fragmentation per se can weaken the positive BEF relationship by decreasing the degree of habitat specialisation of the community.

Habitat loss weakens the positive relationship between grassland plant richness and above-ground biomass

Habitat loss and fragmentation per se have been shown to be a major threat to global biodiversity and ecosystem function. However, little is known about how habitat loss and fragmentation per se alters the relationship between biodiversity and ecosystem function (BEF relationship) in the natural landscape context. Based on 130 landscapes identified by a stratified random sampling in the agro-pastoral ecotone of northern China, we investigated the effects of landscape context (habitat loss and fragmentation per se) on plant richness, above-ground biomass, and the relationship between them in grassland communities using a structural equation model. We found that habitat loss directly decreased plant richness and hence decreased above-ground biomass, while fragmentation per se directly increased plant richness and hence increased above-ground biomass. Fragmentation per se also directly decreased soil water content and hence decreased above-ground biomass. Meanwhile, habitat loss decreased the magnitude of the positive relationship between plant richness and above-ground biomass by reducing the percentage of grassland specialists in the community, while fragmentation per se had no significant modulating effect on this relationship. These results demonstrate that habitat loss and fragmentation per se have inconsistent effects on BEF, with the BEF relationship being modulated by landscape context. Our findings emphasise that habitat loss rather than fragmentation per se can weaken the positive BEF relationship by decreasing the degree of habitat specialisation of the community.