Maintaining Landscape Connectivity Research Articles

Using irregular ranger patrols to quantify elephant occupancy in non‐protected and community‐modified landscapes

AbstractWhile wildlife management efforts have primarily focused on protected areas, unprotected areas – including community‐owned lands – are becoming increasingly important as habitat linkages and dispersal areas between multiple protected areas for species and processes that sustain them. However, these unprotected areas and community lands often lack structured protection measures and face numerous threats to both species and habitats. Involvement of local communities in the management of these areas through community‐led strategies can enhance safety for both people and wildlife, thereby promoting coexistence. To examine the effectiveness of community‐led strategies for managing wildlife outside protected areas, we fit multi‐season occupancy models on African elephant (Loxodonta africana) sightings data collected by volunteer Village Game Scouts (VGS) while on irregular and demand‐driven patrols within Mwanga district in Northern Tanzania. Patrol data were processed using the Spatial Monitoring And Reporting Tool (SMART). We estimated elephant probability of occupancy, detection, colonization and extinction, identifying key elephant dispersal areas in the community‐modified areas within the district. Our results indicate that proximity to Tsavo West National Park and the availability of seasonal water sources positively influenced the probability of elephant colonization. In contrast, the proportion of built‐up and farmed areas, and distance to permanent water sources, negatively influenced the probability of colonization. The number of scout patrols did not significantly influence the probability of elephant colonization or extinction, and elephant occupancy remained relatively stable during the study period. Our study highlights the complementary role of non‐protected areas in maintaining populations of endangered species such as elephants. We demonstrate that structured, volunteer community‐led strategies coupled with effective communication with authorities, can be used to monitor wildlife spatial distribution and identify factors influencing their distribution in non‐protected areas. We recommend community‐led protection measures for corridors and dispersal areas, as well as transboundary collaboration to maintain landscape connectivity for endangered species such as elephants.

Using irregular ranger patrols to quantify elephant occupancy in non‐protected and community‐modified landscapes

AbstractWhile wildlife management efforts have primarily focused on protected areas, unprotected areas – including community‐owned lands – are becoming increasingly important as habitat linkages and dispersal areas between multiple protected areas for species and processes that sustain them. However, these unprotected areas and community lands often lack structured protection measures and face numerous threats to both species and habitats. Involvement of local communities in the management of these areas through community‐led strategies can enhance safety for both people and wildlife, thereby promoting coexistence. To examine the effectiveness of community‐led strategies for managing wildlife outside protected areas, we fit multi‐season occupancy models on African elephant (Loxodonta africana) sightings data collected by volunteer Village Game Scouts (VGS) while on irregular and demand‐driven patrols within Mwanga district in Northern Tanzania. Patrol data were processed using the Spatial Monitoring And Reporting Tool (SMART). We estimated elephant probability of occupancy, detection, colonization and extinction, identifying key elephant dispersal areas in the community‐modified areas within the district. Our results indicate that proximity to Tsavo West National Park and the availability of seasonal water sources positively influenced the probability of elephant colonization. In contrast, the proportion of built‐up and farmed areas, and distance to permanent water sources, negatively influenced the probability of colonization. The number of scout patrols did not significantly influence the probability of elephant colonization or extinction, and elephant occupancy remained relatively stable during the study period. Our study highlights the complementary role of non‐protected areas in maintaining populations of endangered species such as elephants. We demonstrate that structured, volunteer community‐led strategies coupled with effective communication with authorities, can be used to monitor wildlife spatial distribution and identify factors influencing their distribution in non‐protected areas. We recommend community‐led protection measures for corridors and dispersal areas, as well as transboundary collaboration to maintain landscape connectivity for endangered species such as elephants.

Human footprint and rainfall shape Masai giraffe's habitat suitability and connectivity in a multiple‐use landscape

AbstractGiraffe populations have declined by around 40% in the last three decades. Climate change, poaching, habitat loss, and increasing human pressures are confining giraffes to smaller and more isolated patches of habitats. Masai giraffes (Giraffa tippelskirchi) have been subjected to habitat loss and fragmentation, diseases, poaching, and unpredictable calamities such as wildfires and climate change. In this study, we aimed to identify (1) suitable Masai giraffe habitats within the transboundary landscape of Tsavo‐Mkomazi in Southern Kenya and Northern Tanzania; and (2) key connecting corridors in a multiple‐use landscape for conservation prioritization. We combined Masai giraffe presence data collected through a total aerial survey with moderate resolution satellite data to model habitat suitability at 250 m resolution using species distribution models (SDMs) implemented in Google Earth Engine (GEE). Model accuracy was assessed using area under precision recall curve (AUC‐PR). We then used the habitat suitability index as a resistance surface to model functional connectivity using Circuitscape theory and cost‐weighted distance pairwise methods. Human habitat modification, rainfall, and elevation were the main model predictors of Masai giraffe habitat and corridors. On average, our 10‐fold model fitting attained a good predictive performance with an average AUC‐PR = 0.80 (SD = 0.01, range = 0.79–0.83). The model predicted an area of 15,002 km2 as potential suitable Masai giraffe habitat with over 17% outside protected areas within the landscape. Although Tsavo West National Park formed a key habitat and a key connecting corridor, nonprotected community ranches connecting Tsavo West and Tsavo East National Parks are equally important in maintaining landscape connectivity joining more than two Masai giraffe core areas with low resistance and high permeability. To maintain critical Masai giraffe's habitats and landscape functional connectivity, especially in multiple‐use landscapes, conservation‐compatible land use practices, capacity building, and land use planning should be considered at the outset of any new infrastructure development and land use changes. This modeling shows the potential of utilizing remotely sensed information and ground surveys to guide the management of habitats and their connecting corridors across important African landscapes, complementing existing efforts to identify, conserve, and protect wildlife habitats and their linkage zones.

Recent changes in tropical-dry-forest connectivity within the Balsas Basin Biogeographic Province: potential effects on endemic-bird distributions

Maintaining landscape connectivity is a conservation priority for biodiversity as it may mitigate the adverse effects of forest degradation, fragmentation, and climate change by facilitating species dispersal. Despite their importance for biodiversity conservation, Mexican tropical dry forests (TDFs) face high fragmentation rates due to anthropogenic activities. In this study, we analyzed the connectivity dynamics of TDFs in the Balsas Basin Biogeographic Province (BBBP) between 2013 and 2018, focusing on old-growth and secondary TDF covers, including Protected Areas and Important Bird Areas. We evaluated the effects of connectivity loss and gain on the distribution areas of 30 endemic bird species with ecological associations with TDFs in the BBBP. We found expansion in TDFs accounting for a total increase of 227,905 ha due to secondary forest increase (12%). In contrast, old-growth forests experienced a reduction of 66,576 ha in the study area (8%). We also found a decrease in areas with high and very-high connectivity, coupled with an increase in low connectivity, except for TDFs inside Protected Areas, which increased by 3,000 ha, leading to higher connectivity. There was an increase in total forest cover in 27 species’ potential distribution, highlighting the possible role of secondary forests in promoting connectivity between old-growth forest patches. Our results reveal the complex dynamics between forest types, connectivity, and bird-species distributions. Despite an overall increase in forested areas, most TDFs continue to have low connectivity, likely impacting biodiversity, particularly for species that rely on highly conserved ecosystems. This study underscores the importance of integrated conservation strategies considering connectivity, forest recovery, and the dynamics of species-ecosystem interactions.

Human activities influence mule deer use of overpasses across multiple scales

AbstractAnthropogenic linear infrastructures (ALIs), including roads, railways, and canals, provide important resources to humans, but they can affect wildlife through habitat fragmentation and reduced movement through landscapes. To mitigate these effects, overpass crossing structures (i.e., overpasses) can facilitate wildlife movement across ALIs and maintain landscape connectivity. Human activities can potentially influence spatial and temporal patterns in wildlife use of overpasses; however, little information is available about human–wildlife interactions across some types of ALIs. Using remote wildlife cameras, we evaluated human and mule deer (Odocoileus hemionus) use and interactions at 43 overpasses along the Central Arizona Project canal in Arizona, USA, during 2 seasons (warm and cool) from February 2021 to February 2022. Mule deer exhibited spatial avoidance of human activities at overpasses, although the effect varied across seasons and types of human activity. At a broad scale, the presence of recreationists at overpasses did not exclude mule deer from using overpasses to cross the canal; however, human presence reduced mule deer detection probability in the warm season. At a fine scale, mule deer decreased use of overpasses as activity associated with canal personnel (i.e., security and maintenance workers) increased in the cool season. For both seasons, mule deer exhibited greater overlap in daily activity patterns with recreationists compared to canal personnel. Further, mule deer shifted daily activity patterns to be more active earlier in the morning at sites with high amounts of recreational use compared to sites with lower recreational use. Because human activities can influence mule deer crossings at overpasses, managers might consider minimizing human activities at crossing locations to increase wildlife use and promote wildlife movement across canals and other types of ALIs.

Improving landscape connectivity through habitat restoration: application for Asian elephant conservation in Xishuangbanna Prefecture, China.

Habitat restoration is an effective method for improving landscape connectivity, which can reduce habitat fragmentation. Maintaining landscape connectivity could promote connections between habitat, which is extremely essential to preserve gene flow and population viability. This study proposes a methodological framework to analyze landscape connectivity for Asian elephant habitat conservation, aiming to provide practical options for reducing habitat fragmentation and improving habitat connectivity. Our approach involved combining a species distribution model using MaxEnt and landscape functional connectivity models using graph theory to assess the impact on connectivity improvement via farmland/plantation restoration as habitat. The results showed that: (1) there were 119 suitable habitat patches of Asian elephant covering a total area of 1952.41 km2 . (2) The connectivity between habitats improved significantly after vegetation restoration and the gain first decreased and then increased with the increase of dispersal distance. (3) The first few new habitat patches that were identified played an important role in improving connectivity, and the variation rate of connectivity gradually leveled off as the number of new habitats increased. (4) Prioritization of the 25 best new habitat patches increased connectivity from 0.54% to 5.59% as the dispersal distance increased and mainly was located between two Asian elephant distribution regions and two components. Establishment of new habitat patches was effective for improving or restoring connectivity. Our findings can be used as guidance for improving the studied fragmented Asian elephant habitats, and they can also be used as a reference for the habitat restoration of other endangered species heavily affected by habitat fragmentation.

Unveiling the ghosts of landscapes past: Changes in landscape connectivity over the last decades are still shaping current woodland plant assemblages

Abstract In ever‐changing landscapes, there is increasing evidence that current plant assemblages are shaped by the temporal dynamics of landscape connectivity. So far, attempts to take the temporal dynamics of connectivity into account have only focused on the degree of connectivity at one or several moments in time, but neglected the cumulative effects of temporal changes in connectivity. We investigated the effects of the temporal dynamics of landscape connectivity (i.e. the degree of connectivity, the magnitude and the variability of its temporal changes) over the last seven decades on current woodland plant herbaceous assemblages. The assemblages were described using a taxonomic approach combined with a functional approach based on four traits linked to the colonisation capacity of plant species. The taxonomic diversity of current woodland assemblages did not respond to the degree of connectivity nor to the magnitude and the variability of temporal changes, but the mean and/or the diversity of trait values linked to their colonisation capacity did. Responses, mainly driven by generalist species, were modulated by the type of connectivity trend experienced by woodlands. In woodlands experiencing an upward connectivity trend, high magnitude of temporal changes in connectivity increased the abundance of species that invest mostly in sexual reproduction at the expense of vegetative reproduction whereas the degree of connectivity and the variability of its temporal changes had no effect. In woodlands experiencing a downward connectivity trend, the diversity of seed mass values was independent on the magnitude but decreased with the variability of temporal changes, and increased with the degree of connectivity. Synthesis. Overall, we show that, besides the degree of connectivity, the cumulative effects of decades of changes in connectivity shape woodland plant community assembly by selecting for particular trait values in plant species. This study opens new perspectives for integrating the temporal dynamics of landscape connectivity in the theoretical framework of plant assembly rules. It should also be considered in the development of management strategies to restore and maintain landscape connectivity.

Come back to stay: landscape connectivity analysis for the Eurasian otter (Lutra lutra) in the western Alps

Assessing landscape connectivity allows defining the degree to which the landscape facilitates or impedes the movement of a species between resource patches. In this phase of climate change and biodiversity crisis, maintaining landscape connectivity by restoring and protecting connecting areas and corridors is a key strategy to ensure the survival of many species. The Eurasian otter (Lutra lutra) is a freshwater top predator that is slowly recovering after a dramatic decline occurred in central and southern Europe in the last century. To assess the chances of otter recolonization of the western Alps, we analyzed environmental connectivity by applying electrical circuit theory to an expert-based resistance surface using the Circuitscape software. The study area included southeastern France, northwestern Italy, and Switzerland. We produced a cumulative current flow map and a gap analysis was also conducted to highlight the “conservation gaps” for optimal corridors. The results revealed that the orography of the landscape was the main factor influencing the quantity and quality of the pathways in the western Alpine landscapes. As main corridors were concentrated on valley bottoms, human pressure could severely diminish animal movement. Despite this, some heavily populated areas showed high connectivity values. Some important pathways did not fall within protected areas, potentially hindering otter dispersal and highlighting the need to expand the system of protected areas in the Alpine arc. Recolonization of Alpine territories by otters can therefore only occur if connectivity and environmental suitability combine to ensure the animals' survival over time.

Geospatial modelling of overlapping habitats for identification of tiger corridor networks in the Terai Arc landscape of India

Wildlife corridors in a landscape include local vegetation, topography, prey base, water and are associated with isolated wildlife habitat patches. They facilitate maintenance of ecological structure and function as well as provide connectivity to faunal populations supporting genetic transfers, and are elements critical to wildlife management. In this work, habitat patches for tiger, both inside as well as outside of Protected Areas have been identified by developing a Habitat Suitability Index model utilizing Remote Sensing and Geographical Information System datasets for the Terai Arc landscape, India. By using a computational approach based on the framework of theory of complex networks, for exclusively pairwise interactions between the habitat patches, a potential tiger corridor network has been structurally identified and studied in this landscape. The interactions between these habitat patches on a spatial scale has been analyzed as a clique of the corridor network. Further, the Clique Percolation Method has been applied to detect overlapping communities of habitat patches in the landscape. The Cliques required for maintaining contiguity between the habitat patches in order to support tiger movement are validated using field observations of tiger communities within the landscape matrix. The model developed for identification of tiger corridors in this study could potentially be of a vital importance for wildlife stakeholders to better understand and manage tiger populations both within and outside of protected areas. The study also highlights Critical Habitat Patches and their importance in maintaining landscape connectivity for tiger dispersal in the landscape. Using a report published by the Government of India as a benchmark, the model presented in the work is found to have an accuracy of 90.73% in predicting tiger carrying patches and the corridor network in the focal landscape.

Effectiveness of management of the Mesoamerican Biological Corridor in Mexico

As a project of regional conservation, the purpose of the Mesoamerican Biological Corridor in Mexico (MMBC) was to maintain landscape connectivity to ensure the permanence of species and ecological processes. This study appraised the effectiveness of the MMBC management implemented in two Mexican states: Chiapas and Tabasco. The analysis covered the period from design to termination of the project (2000-2018). An evaluation of the MMBC management effectiveness was conducted based on documentary research, mapping of actors, structured interviews, qualitative analysis and application of indicators. The conceptualization of the MMBC had its origin in international organizations and was implemented with a top-down approach at local scale and support from various stakeholders, including governmental and nongovernmental organizations, consultancy agencies and private and community landowners. In both states, the effectiveness of the MMBC management was considered as good, based on strengths such as the adequate design and implementation of actions and the multi-level participation of the stakeholders. However, the consultancy agencies responsible for the management of the MMBC were unable to become self-financed, limiting the long-term continuity of corridor projects. The configuration of the corridor landscapes, which was initially based on ecological criteria, later became subordinate to the acceptance of some landowners, as a key aspect. Implementation became governed by the technical and political processes of negotiation among the stakeholders involved. Ultimately, corridors remained only within the lands where landowners had accepted and cooperated with the MMBC projects.

Island biogeography theory and the urban landscape: stopover site selection by the silver-haired bat (Lasionycteris noctivagans)

Many migratory bats require forested sites for roosting and foraging along their migration path, but increased urbanization and intensive agricultural practices may reduce the availability of stopover sites. Urban forests may provide important stopover habitat, maintaining landscape connectivity in regions where the majority of natural habitat has been cleared for development. Island biogeography theory can be applied to urbanized temperate forest biomes where small urban forests represent islands separated from the larger “mainland” forest. We used acoustic monitoring during the fall migration period to investigate the use of urban forest habitat by a migratory species, the silver-haired bat (Lasionycteris noctivagans (Le Conte, 1831)). We predicted that recorded activity would have a positive relationship with forest patch area and shape and a negative relationship with isolation from other forest patches, as suggested by island biogeography theory. We observed greater activity at larger forest patches, and although relationships for shape and isolation were not statistically supported, the observed patterns were consistent with predictions. Our results demonstrate the need for more in-depth research on the habitat requirements for both migratory and resident bat species and the impact that ongoing urbanization has on local bat populations.

Impact of climate and land cover changes on the potential distribution of four endemic salamanders in Mexico

Anthropogenic changes, such as land use and climate change, are the greatest threats to biodiversity, especially for amphibians, which are the most endangered vertebrate class worldwide. Species distribution modelling was applied to assess how expected future climate and land cover change scenarios might influence the geographic distribution and habitat connectivity of four salamanders endemic to Mexico: Aquiloeurycea cephalica (Cope, 1865), Isthmura bellii (Gray, 1850), Pseudoeurycea robertsi (Taylor, 1939), and Pseudoeurycea leprosa (Cope, 1869). For this, the Community Climate System Model (CCSM4) with two Representative Concentration Pathways (RCP 45 and RCP 85) and two modelling methods (Maxent in ENMeval and an ensemble model in biomod2) were used. The most important environmental variables explaining the distribution of the target species, as well as the environmental niche overlap between them, were also determined. Abies forest cover was one of the most important variables explaining the current distribution of P. robertsi (contribution of 39%), P. leprosa (contribution of 18%), and A. cephalica (contribution of 22%) with a positive effect. The distribution of these three species was also limited by maximum temperatures, whereas the I. bellii distribution was more limited by minimum temperatures. The environmental niches of P. leprosa and A. cephalica were significantly similar (D = 0.637, I = 0.801, p-value = 0.02), as well as the environmental niches of P. robertsi and P. leprosa (D = 0.640, I = 0.797, p-value = 0.01). As expected, all salamander species were predicted to face a reduction in their potential distribution (reductions between 2.64 and 32.16%) and landscape connectivity (reductions between 4.93 and 73.92%) under future scenarios of climate and land cover change. Different models and scenarios were inconsistent in determining which species’ distribution would suffer the biggest reduction in the future. However, P. robertsi suffered the largest reduction in connectivity under both scenarios of climate change. Similarly, our results suggest that Sierra de las Cruces and Corredor Biológico Chichinautzin are very important areas in terms of connectivity. Unfortunately, great losses of Abies and Pinus forests were also predicted to occur in these areas between 2011 and 2014. According to these findings, the preservation of Abies forests of the Trans-Mexican Volcanic Belt is essential to preserve P. robertsi, P. leprosa, and A. cephalica salamanders, whereas the preservation of Corredor Biológico Chichinautzin and Sierra de las Cruces is essential to maintain landscape connectivity for P. leprosa, A. cephalica, and I. bellii. Thus, these areas should be prioritized in conservation programs.

Greenway Network: A Participatory Planning Approach for Municipalities of the South Region of Brazil

Abstract Development of greenways represent a planning strategy that seeks to reconcile both nature conservation and human uses. It is crucial for maintaining landscape connectivity in an increasingly anthropized world. Such strategy encompasses complex socio-ecological variables and its success greatly depends on the integration of different types of knowledge and active support from the local communities and stakeholders. This demands participatory planning processes within multidisciplinary platforms that promote a close collaboration between experts and lay people. The goal of this paper is to describe and analyse a participatory planning approach for the early-stage design of a greenway network for municipalities in South Brazil. The majority of southern Brazilian municipalities contain a very high rate of small farms which are under intensive agricultural production, and consequently, harming the natural landscapes. Actions to effectively tackle this problem are scarcely observed. The procedures encompassed by the approach were determined by the context constraints and potentials that make it applicable in the reality at stake. The approach is focusing on the early-stage design of a greenway network plan and comprises two phases with each a multi-stakeholder workshop for the local landscape analysis and the plan co-design by experts and local actors. The application of the approach in a municipality in southern Brazil has enabled local actors to use key concepts of connectivity planning and foster a critical reflection on local issues, and allowed the incorporation of local knowledge into the solution developed by participants. This resulted in a plan tailored to the local reality.

Landscape Connectivity Analysis and Optimization of Qianjiangyuan National Park, Zhejiang Province, China

As natural ecosystems in most parts of the world come under increasing human influence, fragmentation is becoming the major driving factor of the global biodiversity crisis. Therefore, connectivity between habitat patches is becoming even more important. China began building national parks with the primary purpose of protecting nationally representative natural ecosystems and maintaining the integrity of their structure, processes and functions. Research is necessary to improve the internal connectivity of national parks and to propose suggestions for existing functional zoning and biological corridors. In this study, Qianjiangyuan National Park was selected as an example park, and landscape fragmentation was evaluated exponentially and simulated visually. The habitat characteristics of protected species in the region, morphological spatial pattern analysis and the delta of the probability of connectivity were used together to identify key habitat patches and their importance levels in the study area. Potential habitat corridors in the region were then obtained using least-cost path analysis and gravity modeling methods based on the distribution of key habitat and the migration costs of target species. The results of this study show that the disturbed landscape of the study area is dominated by tea plantations and drylands, with central roads being an important factor affecting the overall landscape connectivity. In terms of the distribution of key habitat patches, the mountains have a high value. In terms of area, their size is not directly proportional to their importance for maintaining landscape connectivity in the region, but large area patches are generally of higher importance. In terms of distance, key habitats that are closer to each other have a stronger correlation and a greater possibility for species migration. Combined with the functional zoning of Qianjiangyuan National Park, the setting of strictly protected areas and recreational areas is reasonable, and traditional use areas and ecological conservation areas could be appropriately adjusted according to the distribution of key habitats. The important corridor in the middle of the ecological conservation area is crucial for the overall connectivity of the national park, and the connectivity between strict protected areas will depend on successful protection of the ecological conservation area.

Land Use Dynamics and Optimization from 2000 to 2020 in East Guangdong Province, China

Anthropogenic land-use change is one of the main drivers of global environmental change. China has been on a fast track of land-use change since the Reform and Opening-up policy in 1978. In view of the situation, this study aims to optimize land use and provide a way to effectively coordinate the development and ecological protection in China. We took East Guangdong (EGD), an underdeveloped but populous region, as a case study. We used land-use changes indexes to demonstrate the land-use dynamics in EGD from 2000 to 2020, then identified the hot spots for fast-growing areas of built-up land and simulated land use in 2030 using the future land-use simulation (FLUS) model. The results indicated that the cropland and the built-up land changed in a large proportion during the study period. Then we established the ecological security pattern (ESP) according to the minimal cumulative resistance model (MCRM) based on the natural and socioeconomic factors. Corridors, buffer zones, and the key nodes were extracted by the MCRM to maintain landscape connectivity and key ecological processes of the study area. Moreover, the study showed the way to identify the conflict zones between future built-up land expansion with the corridors and buffer zones, which will be critical areas of consideration for future land-use management. Finally, some relevant policy recommendations are proposed based on the research result.

Moving through the mosaic: identifying critical linkage zones for large herbivores across a multiple‐use African landscape

Reduced connectivity across grassland ecosystems can impair their functional heterogeneity and negatively impact large herbivore populations. Maintaining landscape connectivity across human-dominated rangelands is therefore a key conservation priority. Integrate data on large herbivore occurrence and species richness with analyses of functional landscape connectivity to identify important areas for maintaining or restoring connectivity for large herbivores. The study was conducted on a landscape with a mosaic of multiple land uses in Laikipia County, Kenya. We used occupancy estimates for four herbivore species [African elephant (Loxodonta africana), reticulated giraffe (Giraffa reticulata), plains zebra (Equus quagga), and Grevy’s zebra (Equus grevyi)] and species richness estimates derived from aerial surveys to create resistance surfaces to movement for single species and a multi-species assemblage, respectively. We validated single-species resistance surfaces using telemetry data. We used circuit theory and least cost-path analyses to model linkage zones across the landscape and prioritize areas for connectivity restoration. Resistance layers approximated the movements of our focal species. Results for single-species and multi-species connectivity models were highly correlated (rp > 0.9), indicating similar spatial patterns of functional connectivity between individual species and the larger herbivore assemblage. We identified critical linkage zones that may improve permeability to large-herbivore movements. Our analysis highlights the utility of aerial surveys in modeling landscape connectivity and informing conservation management when animal movement data are scarce. Our results can guide management decisions, providing valuable information to evaluate the trade-offs between improving landscape connectivity and safeguarding livelihoods with electrified fences across rangelands.

Using stepping-stone theory to evaluate the maintenance of landscape connectivity under China’s ecological control line policy

Developed areas are gradually expanding with the acceleration of urbanization. The degree of fragmentation of urban ecological land is increasing, and the risk of reducing the connectivity between important ecological patches is rising. In this context, the municipal governments in China have delineated ‘ecological control lines’ (ECLs) to protect landscape connectivity—however, its effectiveness has not been evaluated. In the study reported here, circuit theory was used to simulate flow among ecological sources, stepping stones carrying ecological flow were identified, and the effectiveness of the ECL, in terms of maintaining landscape connectivity, was evaluated. In this study, we classified the absence of stepping-stone protection based on stepping-stone area, distribution, and potential loss and identified key stepping-stone categories in urgent need of ECL protection, which will be useful for delineating the ecological red line in the future. The results showed that there were 1488 ecological stepping stones in Shenzhen, with an average area of 0.124 km2 and a total area of 185.2 km2. Under the current ECL protection, five stepping-stone groups were characterized as hotspots lacking protection, and this absence threatened the connectivity between some ecological sources. Through stepping stone classification and analysis, we were also able to show that there were 34 key stepping stones that were not protected effectively by the ECL, and they should be incorporate in the future. Using stepping stone and circuit theory models, our study has provided a reference for policy making that addresses connectivity under landscape fragmentation.

Resistance-Based Connectivity Model to Construct Corridors of the Przewalski’s Gazelle (Procapra Przewalskii) in Fragmented Landscape

Habitat connectivity is indispensable for the survival of species that occupy a small habitat area and have isolated habitat patches from each other. At present, the development of human economy squeezes the living space of wildlife and interferes and hinders the dispersal of species. The Przewalski’s gazelle (Procapra przewalskii) is one of the most endangered ungulates, which has experienced a significant reduction in population and severe habitat shrinkage. Although the population of this species has recovered to a certain extent, human infrastructure severely hinders the gene flow between several patches of this species. Therefore, we used the maximum entropy (MaxEnt) model to simulate the habitat suitability of the Przewalski’s gazelle. In addition, we combined habitat suitability and ecological characteristics of the species to obtain eight habitat patches. Finally, we used the least-cost path (LCP) and circuit theory based on the resistance model to simulate the landscape network of this species. The results showed that habitat patches and connectivity in the east of the Qinghai Lake were crucial to the communication between populations of the Przewalski gazelle, and our study provided important reference for the distribution of important habitats and the construction of corridor between patches. Our study aimed to provide habitat networks and maintain landscape connectivity for achieving the fundamental goal of protecting and revitalizing populations of the Przewalski’s gazelle.

Pairing functional connectivity with population dynamics to prioritize corridors for Southern California spotted owls

AbstractAimLand use change, climate change, and shifts to disturbance regimes make successful wildlife management challenging, particularly when ongoing urbanization constrains habitat and movement. Preserving and maintaining landscape connectivity is a potential strategy to support wildlife responding to these stressors. Using a novel model framework, we determined the population‐level benefit of a set of identified potential corridors for spotted owl population viability.LocationSouthern California, United States.MethodsCombining habitat suitability and dynamic metapopulation models, we compared the benefit of corridors to the Southern California spotted owl population, measured as the increase in the expected minimum abundance, both now and under a future climate. Our approach considered key corridor characteristics important to conservation decisions, namely corridor irreplaceability and local population network benefit.ResultsWe identified two corridors likely to increase Southern California spotted owl expected minimum abundance under current climate conditions. At the regional scale, of the 27 corridors evaluated, one corridor was irreplaceable (i.e., no other corridors in the network could provide a similar increase in abundance when the irreplaceable corridor was removed) and one corridor was identified as redundant (i.e., remaining corridors in the network can provide some of the increases in abundance offered by the removed corridor). Both putative corridors connected two large, populous and similarly sized patches. Additionally, we identified two more corridors at the local scale. We found that, under climate change, population declines may limit the benefit of connectivity for a range‐restricted species like the spotted owl.Main conclusionsOur analytical approach highlights important criteria for corridor identification and prioritization, namely irreplaceability versus redundancy, local versus regional benefit, and corridor impact in a changing landscape. With the capability of incorporating estimated functional connectivity into population dynamics, our modelling framework advances connectivity decision‐making for other species of conservation concern and archetypal taxa within ecological communities.

Road-crossings, vegetative cover, land use and poisons interact to influence corridor effectiveness

Landscape connectivity is essential to conserving resilient wildlife populations in the Anthropocene. Maintaining connectivity requires preserving or restoring patches of habitat, accounting for the behavioral factors that determine movement between patches and mitigating threats. We measured natural and anthropogenic features that influence movement and mortality for bobcats (Lynx rufus) in a system threatened with complete isolation by urbanization. Our overarching objective was to inform local land acquisition and restoration to maintain two last-chance wildlife corridors. We collected five-minute movement data from 36 bobcats in central California to assess features of road-crossing hotspots and model habitat selection, including functional responses to housing densities and vegetation. We collected opportunistic mortalities and assessed rat poison exposure to evaluate edge effects as acute threats. Bobcats strongly selected for natural vegetation, evident at the level of a single tree or shrub. Individuals selected low-density housing (<5 houses/ha) yet avoided high-density housing development and monoculture agriculture. Narrow (<25 m wide) riparian strips were critical to connectivity. Bobcats successfully crossed the busiest highway in the landscape but frequently died when crossing a less-trafficked road with a high median barrier. Vehicles and disease were dominant sources of mortality, while 94% of bobcats were exposed to rat poisons despite California's 2014 regulations implemented to reduced wildlife exposure. Maintaining landscape connectivity requires conserving key habitats, mitigating the effects of infrastructure, and sustaining populations of highly mobile, healthy individuals. Our findings have driven conservation action through land acquisition. We demonstrate how robust, rapid data collection can facilitate real-world conservation outcomes.