High-quality Habitat Research Articles

Systematic design of habitat services network (HSsN) for updating conservation areas in iran's arid and Semi-Arid ecosystems

Threats caused by human activities have reduced the quantity and quality of wildlife habitats connectivity. This research seeks to protect habitat biodiversity by creating a network of high quality habitats that remained. Therefore, it is very necessary to know about the dynamic effects of changes in the landscape pattern on the quality of the habitat, because it helps to preserve biodiversity, guarantee ecological security, and environmental sustainability. In the present study, a systematic process was used to design a network of habitat services comprising hotspots and corridors in arid and semi-arid ecosystems of eastern Iran, South Khorasan Province. In this process, habitat quality was first modeled using the InVEST software, then data mining methods were used to identify habitat hotspots and their spatial distribution. In the next step, habitat corridors were extracted based on the circuit theory and using the Circuitscape software. In the ultimate step, using graph theory based on the concept of ecological security, the connectivity of the habitat network was evaluated. The results of habitat network construction showed that 8% and 6% of the total area of the study area included key habitat patches and corridors, respectively. On the other hand, the overlapping of habitat network components with the conserved areas of the study area showed that free or non-conservation areas make up a significant amount of network components (49.18% of the habitat patch and 80.02% of the habitat corridor). These results reveal the existence of habitat protection potential and can help in updating the new boundaries of conservation areas. Also, the composite indices of dPC and dIIC could determine the importance of each of the network's components in evaluating the connectivity of the habitat network, so that the application of the results can show the priority options to the land managers for protecting the habitat network. In general, the systematic process proposed in this research can be used in planning the sustainable conservation of habitat networks, identifying patterns of ecological security, evaluating and constructing habitat networks in lands with similar climates, and changing and wisely reviewing the conservation area boundaries.

Spatial and temporal evolution of habitat quality and its shrinkage effect in shrinking cities: Evidence from Northeast China

Continued population loss in the context of urban shrinkage has led to the transformation and reconfiguration of urban land use space, which in turn has had a major impact on regional habitats and ecosystem services. To explore the status of habitat quality (HQ) in shrinking cities, based on land use data from 2010 to 2020, this study uses the InVEST model to analyze the spatiotemporal characteristics of HQ in shrinking cities. Then, we reveal the shrinkage effect of HQ in shrinking cities from the perspective of population change rate, and detect the dominant influencing factors of HQ in different types of shrinking cities with the help of geographical detector. The results show that:(1) From 2010 to 2020, the primary land use types in both shrinking and non-shrinking cities of the three northeastern provinces were forestland and cropland. However, there were significant differences in the area of construction land between the two categories of cities. (2) The HQ in both shrinking and non-shrinking cities showed a declining trend, yet the HQ index of shrinking cities was higher than that of non-shrinking cities. (3) The distribution of HQ in shrinking cities has a significant shrinkage effect, and HQ index gradually strengthens as urban shrinkage intensifies. Low-quality habitats have a strong distributional advantage in slightly shrinking cities, while severely shrinking cities tend to be dominated by high-quality habitats. (4) Population profile, economic development, industrial structure and built environment are important factors influencing the spatial heterogeneity of HQ in shrinking cities. However, the spatial determinants of HQ vary significantly among different types of shrinking cities in terms of dimensions and indicators, with two-factor interactions exerting a stronger influence than single-factor impacts. Based on the findings of this study, the government can formulate differentiated habitat protection measures, dynamically adjust, and optimize them according to the distribution characteristics of HQ grades in shrinking cities.

Ecological Security Patterns Research Based on Ecosystem Services and Circuit Theory in Southwest China

The rapid economic development in the Chengdu–Chongqing Economic Circle (CCEC) has exerted significant pressure on the ecological environment of the Sichuan–Chongqing Region in China. Balancing ecological protection and economic development has become an imperative challenge that needs to be addressed. In this study, we employed land use/cover data and environmental threat factors to construct Ecological Security Patterns (ESPs) for the CCEC using the InVEST model and Circuit Theory. The research findings revealed the following key outcomes: (1) The total area of suitable habitat in the CCEC was 208,728.3 km2, accounting for 87.14% of the study area. Habitat quality exhibited regional variations, with higher quality habitats predominantly found in the western and northeastern parts, and lower quality habitats in the central region. (2) The CCEC consisted of areas with low, medium, high, and optimal habitat quality, spanning 140,912.18 km2, 15,341.89 km2, 15,578.38 km2, and 36,895.85 km2, respectively. These areas accounted for 58.83%, 6.40%, 6.50%, and 15.40% of the study area, respectively. (3) The ESPs in the CCEC encompassed 22 ecological nodes, 36 clusters of ecological corridors, and 136 ecological sources. Ecological corridors served as radial connections, linking each ecological node and ecological source along mountain ranges, forested areas, river networks, and valleys. (4) The core ecological regions forming the ESPs of the CCEC included the Qionglai–Minshan–Longquan Mountains in the west, Tiefeng–Fangdou–Qiyue–Wushan Mountains in the east and northeast, and Dalou Mountain in the southeast. These regional-scale findings provide valuable insights for policymakers to implement targeted measures for ecological protection and promote green development. They offer objective guidance and constraints for managing urban expansion and anthropogenic activities, ultimately enhancing the ecological security level of the CCEC.

Prioritisation of Barriers According to Their Impact on Migratory Fish in the Lowland River Basin District

Artificial barriers are one of the most damaging anthropogenic factors, but are also socio-economic constructions, so the decision between removing a barrier and installing a fishway must be justified. The aim was to develop a system to quantify the amount of suitable habitat for migratory fish above barriers, to assess barriers’ passability, to prioritise them in current and historical terms and to take into account the impact of the reservoir in the selection of barrier management alternatives. For this purpose, the proportion of suitable area and the potential number of spawners were calculated separately for the flooded and free-flowing river sections above the barrier. The effect of the flooded area and fishway efficiency on the potential number of individuals was assessed and the historical importance of the areas above each barrier was evaluated. The results show that the proportion of suitable area in the total area above the barriers varies between 5 and 31%. Short river stretches of high habitat quality have a higher reproductive potential than much longer stretches of lower habitat quality. Dams with fishways can still be among the most negatively impacting barriers if they are located in the migration route of fish into a large part of the basin.

Predicting the distribution and characteristics of Chinese pangolin habitat in China: Implications for conservation

The Chinese pangolin (Manis pentadactyla) is on the verge of extinction. Overuse and habitat loss have decimated the pangolin population across China. Understanding the habitat status of pangolins is a prerequisite for conservation, but this understanding is lacking due to difficulties in surveying and monitoring this species. This study used the MaxEnt model to analyze the current habitat distribution of Chinese pangolins by summarizing distribution records for China from 2010–2022. Moderate- and high-quality habitat of Chinese pangolins covers about 554,025 km2, mainly in 10 provinces in East and South China, together with a small area in Yunnan and Tibet. The majority of pangolin habitats (89.32%) were distributed in the forests of low mountains and hills; only 8.92% of habitats overlap with protected areas. Prey abundance and climate are key factors affecting pangolin distribution. Land-use changes leading to habitat encroachment and/or affecting prey abundance, and climate change may underlie their shrinking distribution. Considering that the current protected area coverage of Chinese pangolin habitat is low, we recommend adjusting or expanding the boundaries of protected areas to improve coverage. The focus should be on strengthening the population and habitat management of Chinese pangolin outside protected areas. Within pangolin ranges, conservation can be achieved through improving the education of community residents, implementing stronger community economic development policies, replacing lost logging income from residents’ private forest land with economic compensation, and strictly regulating the location of infrastructure and residential area construction. The goal of these four key actions is to increase the public’s awareness and enthusiasm for pangolins, reduce the willingness of community residents to hunt pangolin, and prevent the destruction of and encroachment into existing pangolin habitat.

Study on the impact of reclamation and development of Yancheng coastal wetlands on the spatio-temporal evolution of wintering Anatidae habitat

As a World Natural Heritage Site primarily focused on protecting migratory bird habitats, the Yancheng coastal wetland is also an important land resource reserve area in China. With a long history of reclamation, the impact of reclamation on waterbird habitats has attracted widespread attention. Therefore, this study was based on the distribution data of wintering Anatidae from 1987 to 2020 and coastal land reclamation data. The landscape development intensity (LDI) index and MaxEnt model were used to reveal the spatiotemporal changes in reclamation development intensity and identify the spatiotemporal evolution characteristics of Anatidae habitats. A geographical weight regression (GWR) model was used to analyze the local differences for the impact of changes in reclamation development intensity on the spatiotemporal distribution of Anatidae habitats. The results showed that the area of land types with higher reclamation intensity in the study area increased rapidly from 1987 to 2020, and the overall reclamation intensity showed a pattern of low in the northeast and high in the southwest. The high-intensity range in 1987 was 5.01 ∼ 6.00, and the reclamation intensity in the western area of Dafeng to Tiaozini was generally greater than 8.01 in 2020. From 1987 to 2020, the population of Anatidae first decreased and then increased, with a clear southward shift in spatial distribution. The evaluation results of suitable habitats revealed that the most suitable area significantly declined from 1280.76 hm2 in 1997 to 60.19 hm2 in 2020, which indicated that the patch space of high-quality habitats was further compressed. The area with the greatest positive impact for the intensity of reclamation and development on habitat suitability from 1987 to 1997 was concentrated near the Beihuanchong area, while in 2007, the negative impact was mostly distributed in the northern and western Hexin area. The regression coefficient ranged from −0.665 ∼ -0.513. The negative impact of reclamation and development further deteriorated in 2020, with a negative correlation coefficient ranging from −1.642 ∼ -0.699. There were significant differences in the impact of environmental variables on the distribution of Anatidae habitats in different periods. In this study, a habitat protection and restoration pattern for Anatidae is proposed, which may provide an important reference for the protection of wintering Anatidae populations and the structural restoration of habitats in Yancheng coastal wetlands.

Large-scale genotypic identification reveals density-dependent natal dispersal patterns in an elusive bird of prey

BackgroundNatal dispersal, the distance between site of birth and site of first breeding, has a fundamental role in population dynamics and species’ responses to environmental changes. Population density is considered a key driver of natal dispersal. However, few studies have been able to examine densities at both the natal and the settlement site, which is critical for understanding the role of density in dispersal. Additionally, the role of density on natal dispersal remains poorly understood in long-lived and slowly reproducing species, due to their prolonged dispersal periods and often elusive nature. We studied the natal dispersal of the white-tailed eagle (Haliaeetus albicilla) in response to local breeder densities. We investigated the effects of the number of active territories around the natal site on (a) natal dispersal distance and (b) the difference between natal and settlement site breeder density. We were interested in whether eagles showed tendencies of conspecific attraction (positive density-dependence) or intraspecific competition (negative density-dependence) and how this related to settlement site breeder density.MethodsWe used a combination of long-term visual and genotypic identification to match individuals from their breeding site to their natal nest. We identified natal dispersal events for 355 individuals hatched between 1984 and 2015 in the Baltic Sea coast and Arctic areas of Finland. Of those, 251 were identified by their genotype.ResultsIndividuals born in high-density areas dispersed shorter distances than those born in low-density areas, but settled at lower density breeding sites in comparison to their natal site. Eagles born in low natal area densities dispersed farther but settled in higher density breeding sites compared to their natal site.ConclusionsWe show that eagles might be attracted by conspecifics (positive density-dependence) to identify high-quality habitats or find mates, but do not settle in the most densely populated areas. This indicates that natal dispersal is affected by an interplay of conspecific attraction and intraspecific competition, which has implications for population dynamics of white-tailed eagles, but also other top predators. Furthermore, our study demonstrates the value of long-term collection of both nestling and (non-invasive) adult DNA samples, and thereafter using genotype matching to identify individuals in long-lived and elusive species.

Niche overlap across landscape variability in summer between two large herbivores using eDNA metabarcoding.

Understanding the relationship between a species feeding strategy and its environment (trophic ecology) is critical to assess environmental requirements and improve management policies. However, measuring trophic interactions remains challenging. Among the available methods, quantifying the plant composition of a species' diet indicates how species use their environment and their associated niche overlap. Nevertheless, most studies focusing on herbivore trophic ecology ignore the influence that landscape variability may have. Here, we explored how landscape variability influences diet composition through niche overlap. We used eDNA metabarcoding to quantify the diet composition of two large herbivores of the Bialowieza Forest, red deer (Cervus elaphus) and European bison (Bison bonasus) to investigate how increasing habitat quality (i.e. higher abundance of deciduous forage species) and predation risk (i.e. density of wolf in the area) influence their diet composition and niche partitioning. Our findings indicate diet composition is non-homogeneous across the landscape, both within and between species. Red deer showed greater diet variability and lower niche overlap within species compared to bison. We detected a reduction of niche overlap for red deer with increasing predation risk, leading to more dissimilar diets, suggesting their feeding behaviour is affected by wolf presence. This correlation was not found for bison, which are rarely predated by wolf. Higher habitat quality was associated with higher niche overlap only within bison, probably due to their suboptimal feeding strategy as browsers. These results show the importance of integrating environment-induced diet variation in studies aimed at determining the landscape usage or niche overlap of a species.

Can environmental legislation protect a threatened apex predator across different land tenures?

Ecological impact assessments are undertaken in compliance with legislative mandates to evaluate the effects of proposed habitat modification. This task becomes complex when evaluating the impacts on highly mobile species like apex predators. Despite their importance to ecosystem function, environmental policies may inadequately protect apex predator habitat. Here we provide a case study that examines the efficacy of legislation and impact assessment tools in protecting habitat for a wide-ranging and threatened apex predator. The high resource requirements of apex predators, and their utilisation of large areas of high-quality habitat make them ideal conservation surrogates for other less resource demanding species, and as such good case studies in assessing the effectiveness of policy. The powerful owl (Ninox strenua) occurs across many landscape types throughout its distribution, including large tracts of private property and public landholdings, making this species difficult to assess through impact assessments. To examine the level of legislative protection for powerful owls, and how well their habitat use is captured, we compared GPS tracking data to environmental policy and industry impact assessment tools. We found that legislation has limited potential to protect powerful owl habitat and owls are likely dismissed from impact assessments due to their cryptic and wide-ranging behavioural traits. The existing legislative safeguards seem inadequate, and these shortcomings are likely contributing to species decline. There is a critical need for policy to be applicable to both public and private land tenure, and for legislation and impact assessment tools to incorporate research data for effective conservation and management.

Trout and invertebrate assemblages in stream pools through wildfire and drought

Abstract Climate change is increasing the frequency, severity, and extent of wildfires and drought in many parts of the world, with numerous repercussions for the physical, chemical, and biological characteristics of streams. However, information on how these perturbations affect top predators and their impacts on lower trophic levels in streams is limited. The top aquatic predator in southern California streams is native Oncorhynchus mykiss, the endangered southern California steelhead trout (trout). To examine relationships among the distribution of trout, environmental factors, and stream invertebrate resources and assemblages, we sampled pools in 25 stream reaches that differed in the presence (nine reaches) or absence (16 reaches) of trout over 12 years, including eight reaches where trout were extirpated during the study period by drought or post‐fire flood disturbances. Trout were present in deep pools with high water and habitat quality. Invertebrate communities in trout pools were dominated by a variety of medium‐sized collector–gatherer and shredder invertebrate taxa with non‐seasonal life cycles, whereas tadpoles and large, predatory invertebrates (Odonata, Coleoptera, Hemiptera [OCH]), often with atmospheric breather traits, were more abundant in troutless than trout pools. Structural equation modelling of the algal‐based food web indicated a trophic cascade from trout to predatory invertebrates to collector–gatherer taxa and weaker direct negative trout effects on grazers; however, both grazers and collector–gatherers also were positively related to macroalgal biomass. Structural equation modelling also suggested that bottom‐up interactions and abiotic factors drove the detritus‐based food web, with shredder abundance being positively related to leaf litter (coarse particulate organic matter) levels, which, in turn, were positively related to canopy cover and negatively related to flow. These results emphasise the context dependency of trout effects on prey communities and of the relative importance of top‐down versus bottom‐up interactions on food webs, contingent on environmental conditions (flow, light, nutrients, disturbances) and the abundances and traits of component taxa. Invertebrate assemblage structure changed from a trout to a troutless configuration within a year or two after trout were lost owing to post‐fire scouring flows or drought. Increases in OCH abundance after trout were lost were much more variable after drought than after fire. The reappearance of trout in one stream resulted in quick, severe reductions in OCH abundance. These results indicate that climate‐change induced disturbances can result in the extirpation of a top predator, with cascading repercussions for stream communities and food webs. This study also emphasises the importance of preserving or restoring refuge habitats, such as deep, shaded, perennial, cool stream pools with high habitat and water quality, to prevent the extirpation of sensitive species and preserve native biodiversity during a time of climate change.

Spatial-temporal changes of landscape and habitat quality in typical ecologically fragile areas of western China over the past 40 years: A case study of the Ningxia Hui Autonomous Region.

In this paper, we use the InVEST model and five periods of land use data from 1980 to 2020 to assess the habitat quality of the Ningxia Hui Autonomous Region in Western China, which has characteristics of a typical fragile ecosystem. We further analyse the spatial and temporal characteristics of habitat quality evolution and its relationship with land use and landscape pattern indices to explore the close relationship between regional habitat quality changes and human natural resource conservation and utilization. The research results show that the overall habitat quality of Ningxia Hui Autonomous Region was stable and at a moderate level (0.57-0.60) during the 40 years from 1980 to 2020; Habitat patches (2020) with low (24.89%), high (22.45%) and very high (29.81%) quality occupy a larger proportion of the area, followed by very low (13.31%) and moderate levels (9.54%). Over the past 40 years, there have been 275 sample sites in Ningxia where habitat quality has deteriorated, 1593 sample sites where the habitat quality has remained stable, and 184 sample sites where the habitat quality has increased. From 1980 to 2020, the Mean Patch Area of landscape types in Ningxia decreased by 25.9 hm2. The Patch Density increased by 0.06 /hm2. The Largest Patch Index decreased by 15.69%. The Edge Density increased by 2.5 m/hm2. The Contagion Index decreased by 2.99%. The Area-Weighted Mean Patch Fractal Dimension remained basically unchanged (0.01). The Landscape Shape Index showed a trend of first increasing and then decreasing, increasing by 13.94. The Area-Weighted Mean Shape Index has been reduced by 9.45. The Shannon Diversity Index and Shannon Evenness Index both show an increasing trend, but the amplitude is relatively small, with 0.09 and 0.04, respectively. There was a significant spatial aggregation of high and low habitat quality in Ningxia, with high values usually distributed in the northern and southern areas with good natural conditions and low values distributed in areas with frequent human activities and poor natural conditions. The decrease in habitat quality in Ningxia was mainly due to the expansion of cultivated land and construction land, the increase in landscape fragmentation and the resulting decrease in connectivity. On the other hand, due to the implementation of ecological protection measures, such as the project of returning farmland to pasture and grass to forest, the quality of habitats in Ningxia increased. The conclusions of this study support the idea that the conservation of habitat quality in ecologically fragile areas should fully preserve the original natural habitats and reduce the interference of human activities to increase the habitat suitability of the landscape and the habitat connectivity between patches. At the same time, targeted ecological protection policies should be developed to restore the areas where the habitat quality has been damaged and ultimately maintain the stability of biodiversity and ecosystems in ecologically fragile areas. Meanwhile, for ecologically fragile areas with similar ecological characteristics to those of Ningxia, our research supports the idea of increasing the protection of the stability of the original habitats, increasing the proportion of ecological restoration projects, financial investment and seeking cooperation with local community managers and residents will help to improve the quality of the regional habitats and the enrichment of the biodiversity, and ultimately promote the harmonious coexistence of human beings and nature in the modernized sense of the word.

Spatiotemporal variation of habitat quality and its response to fractional vegetation cover change and human disturbance in the Loess Plateau

It is of great practical significance to regional ecological conservation and restoration to explore the spatiotemporal variation characteristics of habitat quality in the ecologically fragile Loess Plateau. This study firstly explored the habitat quality in the Loess Plateau during 2000-2020 with the Integrated Valuation of Ecosystem Services and Trade-offs model. Then this study revealed the response characteristics of habitat quality to the fractional vegetation cover (FVC) change and human disturbance with the geographically weighted regression (GWR) model. Results showed habitat quality tended to improve in 51.16% of the study area, and area of high or very high habitat quality increased by 1.78%. Besides, FVC showed dominantly significant increase (62.42%) and high stability (69.66%) in the study area, and human disturbance increased remarkably in 18.11% of the study area but maintained the same level in 91.83% of the study area. Additionally, areas with positive correlation between habitat quality change and FVC and between habitat quality change and human disturbance change accounted for 52.56% and 37.38% of the study area, respectively, indicating FVC played dominant role in affecting the regional habitat quality variation. This study can provide important decision support information for the future ecological conservation of the Loess Plateau.

Spatiotemporal Evaluation of Regional Land Use Dynamics and Its Potential Ecosystem Impact under Carbon Neutral Pathways in the Guangdong–Hong Kong–Macao Greater Bay Area

The spatiotemporal distribution of ecosystem service values (ESVs) and ecological risk are critical indicators to represent the regional ecological protection level and potential of sustainable development, which largely depend on land-use patterns. Aiming to contribute to global climate mitigation, China has proposed dual-carbon goals that would remarkably influence the land-use/cover change (LUCC) distribution. Based on the Landsat land cover data of 2000, 2010 and 2020 and multisource satellite products, several driving factors are integrated into the patch-generating land use simulation (PLUS) model to simulate future LUCC patterns for the Guangdong–Hong Kong–Macao Greater Bay Area (GBA) under rapid urbanization, cropland protection and carbon neutral (CN) scenarios from 2020 to 2050. Spatial–temporal ecosystem service and ESVs are allocated using INVEST and the equivalent factor method and thus ecological risks are evaluated using the entropy method. Results indicate that forest growth is the largest under the CN scenario, especially in the northwestern and northeastern GBA, exceeding 25,800 km2 in 2050, which results in both the highest habitat quality and carbon storage. The largest ESVs, reaching higher than 5210 yuan/pixel, are found in the CN scenario, particularly expanding toward the suburban area, leading to the lowest ecological risks. From 2020 to 2050, habitat quality, carbon storage and ESVs improve, while ecological risks decline in the CN scenario. This research provides implications for economic and ecological balanced development and gives references to the carbon-neutral pathway for the GBA.

Exploring the spatial configuration of tourism resources through ecosystem services and ethnic minority villages

The rampant and unregulated development of natural landscapes has depleted vital environmental resources, degraded ecosystems, and diminished the allure of ecotourism. Identifying natural spaces suitable for tourism development using a holistic approach that evaluates surrounding ecosystem structure and function is therefore imperative to safeguarding ecological integrity and fostering sustainable economic progress. Leveraging the InVEST model and Kernel Density Estimation (KDE), we assessed the spatial distribution of natural landscape resources and the density of ethnic minority villages to identify potential areas suitable for ecotourism development within the fragile Karst Region of Qiandongnan Miao and Dong Autonomous Prefecture (QMDA), southeastern Guizhou Province, China. Results showed that habitat quality in QMDA was relatively high, with high-quality habitat (Class V) covering 19,554.76 km2, accounting for 65% of the total study area. Optimal natural landscape resources gravitated predominantly towards Liping and Rongjiang, collectively occupying 16% and 12% of the total optimal natural landscape resources, respectively. A total of 3439.95 km2 of potential natural resource development space was identified, with a discernible spatial distribution where the western region of the study area surpassed the eastern counterpart, and the southern region exceeded the northern expanse. The potential development space of tourism resources spanned a cumulative area of 1245.84 km2, located predominately in Kaili, and Danzhai, accounting for 26% and 16% of the total potential development space of tourism resources, respectively. To ensure sustainable use of ecological and cultural assets in QMDA, it is recommended that zoning and regulatory measures that encompass both ecological and touristic domains be enacted. Our findings contribute to a scientific foundation for the pursuits of ecological preservation and the administration of tourism planning for QMDA.

Study of spatiotemporal variation and driving factors of habitat quality in the northern foothills of the Qinling Mountains: a case study of Xi’an, China

As earth surface human activities become more frequent, global ecosystem service functions and especially biodiversity maintenance functions are challenged. This study aimed to analyze spatiotemporal changes in Xi‘an section of the northern foothills of the Qinling Mountains from 1990 to 2020. Temporal and spatial changes in habitat quality in the study area were visualized using InVEST model and land use data, and factors affecting habitat quality were analyzed using Geodetector. The results showed that during the study period, the cultivated land, grassland, and water decreased by 16.40%, 74.37%, and 35.39%, respectively, while the area of forest land and construction land increased, among which the construction land increased by 117.70%, the largest increase, and the forest land increased by 8.47%. The main changes in land use are the conversion of cultivated land into forest land and construction land, and the conversion of grassland into forest land and cultivated land. During the period 1990–2020, the average habitat quality index in the study area changed from 0.8617 to 0.8585, showing a slow decreasing trend. The spatial distribution of habitat quality showed a trend of “high in the south, moderate in the north, and low in the northwest”. The high habitat quality was mainly concentrated in the southern forest land, the middle habitat quality was mainly distributed in the northern cultivated land, and the low habitat quality was mainly distributed in the northwest construction land. The land use type has a great influence on habitat quality, and the interaction between any two factors is stronger than that of a single factor. The temporal and spatial variation of habitat quality is influenced by both natural and human factors. This study provides a theoretical basis for ecological protection and nature reserve planning in the Qinling Mountains region.

Climate-related habitat variations of Humboldt squid in the eastern equatorial Pacific Ocean

An integrated habitat suitability index (HSI) model was developed in this study for Dosidicus gigas in the eastern equatorial waters of the Pacific Ocean to explore climate-related spatial and temporal variability in the habitat distribution pattern based on three crucial environmental variables: sea surface temperature (SST), sea surface salinity (SSS) and chlorophyll-a concentration (Chl-a). Results revealed that the HSI model could accurately predict potential habitats for D. gigas. The habitat suitability varied significantly by month, with highest suitability in April and lowest in March. Besides, from December to May, the longitudinal gravity center of the fishing grounds (LONG) and the HSI overall shifted eastward and the latitudinal gravity center shifted northward then southward. In comparison to the warm ENSO phases in 2019, the cold ENSO phases in 2018 produced increased suitable habitat from December to May, leading to a significantly higher CPUE. Prospective high-quality habitats in 2018 primarily occurred in the western regions, with the exception of December, which resulted in a more westward distribution of LONG from January to May. High-quality habitats moved northward from December to February and southward from March to May 2018, compared to minor latitudinal movement in 2019. It was inferred that annual variations in squid abundance and distribution were largely affected by the SST-related habitat pattern of D. gigas in the eastern equatorial waters. Our findings suggested that D. gigas habitats clearly varied by month and year and were greatly influenced by climate-induced environmental changes.

Dynamic simulation of land use change and habitat quality assessment under climate change scenarios in Nanchang, China.

Investigating habitat quality under different climate scenarios holds significant importance for sustainable land resource management and ecological conservation. In this study, considering Nanchang as a case study, a coupled patch-generating land use simulation (PLUS) and system dynamics (SD) model was employed in the simulation and prediction of land usage under shared socioeconomic pathway (SSP) and representative concentration pathway (RCP) scenarios. To assess the habitat quality in Nanchang from 2000 to 2020 and in 2030 under three diverse climate scenarios, we used the Integrated Valuation of Ecosystem Services and Trade-offs (InVEST) model to analyze spatial and temporal changes. The findings indicate that the regions of forest land, cultivated land, and grassland in Nanchang City will dramatically decrease by 2030, the construction land will rapidly expand, and the fluctuations in the unutilized land and water area will be minimal. Additionally, the habitat quality declined from 2000 to 2020, and its spatial distributions changed. Zones having a high overall habitat quality were distributed in the mountains, hills, and lake areas, whereas those with relatively low quality were found in cultivated and urban areas. Under three climate scenarios, in 2030, the habitat quality index for Nanchang City will show a decreasing trend, mainly owing to areas with an index of 0.3-0.5 transitioning to <0.3. Considering each scenario, the degree of habitat degradation increased in the order SSP585>SSP245>SSP119. The findings of this study will inform high-quality development and biodiversity conservation in Nanchang City.

Construction of multi-level ecological security network in fragmented nature landscape using the three-dimensional framework of ecological adaptability

As the basis for constructing ecological security network, the ecological source has been broadly understood as larger patches that provide important ecosystem services and high comprehensive habitat quality. But the traditional methods for identifying ecological source (e.g. selecting natural vegetation patches and connectivity analysis) are not suitable for the Yanhe River Basin due to its fragmented patches and high vegetation cover. With the progress of research, the multidimensional evaluation framework is used to extract ecological source to mine more function and characteristic of ecosystem. Considering the fragmented nature of patches and the rapid recovery characteristics of vegetation in the Yanhe River Basin, a comprehensive evaluation model was developed based on the three-dimensional framework of ecological adaptability cycle (potential-resilience-connectivity) to extract ecological source. Additionally, due to the insufficient size of the extracted ecological source area to meet the increasing demand for ecosystem services in the future, the potential patches with high ecosystem services and large distribution were considered as secondary ecological source, and the patches with weak connectivity but high potential resilience were as considered tertiary ecological source. Finally, the ecological corridors were delineated based on the three ecological sources and the selected ecological resistance surface. The primary ecological sources were predominantly located in the central region, where grassland was the dominant land use type. The secondary ecological sources were mainly distributed in the southern woodland belt with the highest ecological services, but further enhancements to these services were unattainable. The tertiary ecological sources were mainly distributed in the western region and represented high-quality potential targets for future ecological source expansion. Therefore, it is recommended to give priority to the construction of a primary ecological corridors. The secondary ecological corridors exhibit the lowest comprehensive resistance, and can be constructed concurrently with the primary ecological corridors. Given its highest total comprehensive resistance, construction of tertiary ecological corridors should be contingent upon economic feasibility.

Modeling habitat quality for rangeland ecosystem restoration in the Alledeghi Wildlife reserve, Ethiopia

Assessment of habitat quality is important for the planning and management of conservation measures at a landscape level. The Alledeghi Wildlife Reserve (AWR) is an iconic wildlife conservation area because it not only contains charismatic wildlife species but also serves as a reliable livestock rangeland. The study aimed to assess habitat quality based on landscape-specific habitat threat information in the AWR using InVEST software. it is the first attempt to model the habitat quality of the landscape using expert-driven information. Six important threats were considered, namely, invasive species, bush encroachment, livestock incursion, fire, habitat destruction, and distance to roads. The quantified habitat quality was classified into low, moderate, and high. The results revealed that the quality of the habitat declined in the study area between 1998 and 2016. The high-quality habitat had a larger extent covering about 837 km2 (57.4%) in 1998 but it was reduced by 128 km2 (64%) during the study period. Conversely, moderate quality and low-quality habitats have increased from 78 km2 (5.35%) in 1998 to 206 km2 (14.12%) in 2016; and from 544 km2 (37.3%) in 1998 to 619 km2 (42.13%) in 2016 respectively. The decline in habitat quality was mainly associated with increased livestock incursion and expansion of invasive species which resulted in rapid land use changes. Thus, it is critical to undertake serious conservation measures to enhance biodiversity and ecosystem services in the AWR and to substantively contribute to the improved livelihood of the pastoral community.

Ecological monitoring using Collembola metabarcoding with extremely low bycatch amplification

Collembola are used widely to monitor soil health and functional parameters. Recent developments in high throughput sequencing (especially metabarcoding) have substantially increased their potential for these ends. Collembola are especially amenable to metabarcoding because of their small size, high abundance, and ubiquity in most habitat types. However, most Collembola sampling protocols collect a substantial and highly varied bycatch that can be a considerable impediment to metabarcoding, especially because of data lost to non-target species. We designed a primer set amplifying the D2 expansion segment of ribosomal DNA that is highly conserved across Collembola and successfully excludes from amplification nearly all other invertebrate taxa. We tested the diagnostic power of the primer set by clearly distinguishing Collembola communities between forest sites with differing habitat qualities in São Paulo State, Brazil. The oligos amplified all Collembola orders previously encountered in the sampling locations, with no non-target amplification, and also excluded the closely related Protura and Diplura. Alpha diversity (OTU count) and phylogenetic diversity was significantly higher in high quality habitats. Moreover, the beta diversity indices successfully differentiated high and low-quality habitats. This new addition to the biomonitoring toolbox greatly increases the accessibility of Collembola metabarcoding for various types of habitat assessments.