Potential Movement Corridors Research Articles

Improving urban flyways for bats: the importance of tree canopy structure

Urbanization can hinder movement and restrict landscape permeability for wildlife. However, there is the potential to improve landscape connectivity by establishing and maintaining movement corridors throughout urban areas. One way to achieve this is through the urban forest; the collection of trees in an urban area. Specifically, it is the characteristics of trees within this forest that can provide the structural and functional connectivity that enables wildlife to move effectively through urban areas. To investigate this, we explored the influence of four tree characteristics, alone and in combination, on bat commuting activity along 30 potential movement corridors in an urban setting in north central Texas. Along 10, 30, and 50 m corridor sections, we calculated percent canopy cover, maximum gap distance between canopies, and canopy rugosity using a 60 cm resolution tree canopy layer, while maximum tree height was determined in situ. We then conducted behavioral observations using thermal cameras and acoustic monitoring along the 10 m section of each site between March and September of 2022 and 2023 to determine the amount of time bats were observed commuting/h and species present. Our analysis revealed that increasing percent canopy cover and rugosity positively influenced commuting activity up to a certain threshold (> 60% and > 1.3, respectively), beyond which they may became detrimental. In contrast, the presence of gaps in the canopy lowered commuting, while tree heights > 11 m increased this activity. When considered together, bats in our study area showed a preference for commuting routes with tall trees and straighter, less cluttered canopies with no gaps. Additionally, sites with these features had a greater species diversity. These findings suggest that we can manage and plan the urban forest by establishing an interconnecting network of tree‐lines and forest edges to enhance landscape permeability for bats and subsequently aid urban bat conservation.

A Canada-wide macro assessment of protected area connectivity

Protected areas have become increasingly important for preventing biodiversity declines. However, their effectiveness depends, in part, on how well they are connected with other viable habitats because maintaining and enhancing species movement is critical for population persistence. We used human footprint data to identify potential movement corridors (within maximum distances of 5 and 50 km) among Canadian protected areas. We then compared the degree of connectivity for government protected areas, private protected areas, Indigenous managed lands, and a control (randomly sampled lands). At a maximum distance of 5 km, compared to the control group, government protected areas had 5.6 times more connections, private protected areas had 5.1 times, and Indigenous managed lands (e.g., Indigenous Protected and Conserved Areas) had 4.8 times. At a maximum distance of 50 km, government and private protected areas had 2.6 and 1.4 times the number of connections than the control group, respectively, but Indigenous managed lands had fewer connections than the control. Among private protected areas, at both maximum distances, conservation agreements had approximately 1.3 times the number of connections than fee simple properties. Our results highlight differences in connectivity between protected area types and the disparity in connectivity between government protected areas and their non-governmental counterparts.

Data-integration of opportunistic species observations into hierarchical modeling frameworks improves spatial predictions for urban red squirrels

The prevailing trend of increasing urbanization and habitat fragmentation makes knowledge of species’ habitat requirements and distribution a crucial factor in conservation and urban planning. Species distribution models (SDMs) offer powerful toolboxes for discriminating the underlying environmental factors driving habitat suitability. Nevertheless, challenges in SDMs emerge if multiple data sets - often sampled with different intention and therefore sampling scheme – can complement each other and increase predictive accuracy. Here, we investigate the potential of using recent data integration techniques to model potential habitat and movement corridors for Eurasian red squirrels (Sciurus vulgaris), in an urban area. We constructed hierarchical models integrating data sets of different quality stemming from unstructured on one side and semi-structured wildlife observation campaigns on the other side in a combined likelihood approach and compared the results to modeling techniques based on only one data source - wherein all models were fit with the same selection of environmental variables. Our study highlights the increasing importance of considering multiple data sets for SDMs to enhance their predictive performance. We finally used Circuitscape (version 4.0.5) on the most robust SDM to delineate suitable movement corridors for red squirrels as a basis for planning road mortality mitigation measures. Our results indicate that even though red squirrels are common, urban habitats are rather small and partially lack connectivity along natural connectivity corridors in Berlin. Thus, additional fragmentation could bring the species closer to its limit to persist in urban environments, where our results can act as a template for conservation and management implications.

Sex-specific connectivity modelling for brown bear conservation in the Carpathian Mountains

ContextRomania is currently one of the best-connected landscapes, with high-quality habitats and a high density of brown bears. However, regional development measures are needed for the nation’s economic growth, and without responsible government actions, these measures pose a threat to brown bear connectivity, a vital pillar of the entire Carpathian region. Despite having important implications for the species conservation, bears sex-specific behaviour has been overlooked in connectivity assessments.ObjectivesThe study’s main goals were to (i) develop sex-specific distribution and connectivity models, (ii) assess the movement patterns differences between females and males, and (iii) identify high-quality areas to be secured for species connectivity conservation.MethodsWe designed a methodological framework based on interdisciplinary approaches and modelling tools for landscape connectivity combined with novel spatial analysis. Telemetry data of sixteen bears (females and males) were utilized to predict habitat selection (MaxEnt), and circuit-theoretic approaches (Circuitscape) were applied to identify the potential movement corridors of both sexes and high-priority areas.ResultsThe obtained results provided new evidence on the uneven movement patterns and pathways used by males and females in the study region. Males’ movement preferences were related to river shores and dense forest coverage areas, avoiding urban areas, while females were predicted to move across forested and open areas and were more tolerant to human‐modified areas. Three high-quality areas were delineated for both sexes, and connectivity conservation efforts are needed due to the vicinity of anthropic pressures.ConclusionsThis study depicts the usefulness of combining interdisciplinary approaches and provides planners, managers, and decision-makers with practical solutions to address sustainable design and management within the intervened landscapes. Using separate female and male spatial models for leading management and conservation measures, setting connectivity targets within environmental and impact assessments while adopting conservation easements could secure a safety network for biodiversity conservation in the Carpathians.

Movement of forest‐dependent dung beetles through riparian buffers in Bornean oil palm plantations

AbstractFragmentation of tropical forests is increasing globally, with negative impacts for biodiversity. In Southeast Asia, expansion of oil palm agriculture has caused widespread deforestation, forest degradation and fragmentation.Persistence of forest‐dependent species within these fragmented landscapes is likely to depend on the capacity of individuals to move between forest patches. In oil palm landscapes, riparian buffers along streams and rivers are potential movement corridors, but their use by moving animals is poorly studied.We examined how six dung beetle species traversed riparian buffers connected to a continuous forest reserve area within an oil palm plantation in Sabah, Malaysian Borneo. We used a mark–release–recapture study and a new Bayesian Joint Species Movement Modelling (JSMM) approach, extended to a continuous capture process model.Dung beetle species were fairly generalist in their habitat use, but two species showed a statistically supported preference for riparian buffer forest over oil palm, and one species showed a strong preference for forest reserve over riparian buffer, indicating the importance of forested areas within oil palm landscapes for some species.A land‐use change simulation indicated that the loss of riparian buffers in oil palm will result in reduced movement by forest‐dependent species.Synthesis and applications. Our results provide evidence for the use of riparian buffers in oil palm plantations for forest‐dependent dung beetle species, strengthening the case for their retention, restoration and re‐establishment. Furthermore, our study demonstrates the wider applicability of the Joint Species Movement Modelling (JSMM) framework to assess movement behaviour of species in fragmented landscapes, a vital tool for future forest and landscape management and conservation prioritisation exercises.

The least‐cost path analysis of landscape genetics identifies two dispersal routes for the threatened Kaiser's mountain newt (Caudata: Salamandridae)

Variation in landscape features plays an important role in shaping the distribution of species in natural populations. These can influence population connectivity, gene flow, genetic drift, and ultimately the genetic structure and diversity of isolated populations. In this study, we aimed to identify the impact of landscape heterogeneity on the dispersal patterns of the threatened Kaiser’s mountain newt, Neurergus kaiseri. We integrated population genetics and geospatial data to predict the rates and patterns of genetic differentiation as well as to identify potential movement corridors among populations. For this purpose, we used two mitochondrial DNA markers and combined data on genetic subdivision (θST) and least-cost path (LCP) analyses from 15 fragmented highland streams and spring-ponds representing the entire species distribution area. Five possible dispersal routes used in this study were straight-line, stepping-stone, least cost slope, stream likelihood and combination least cost slope/stream likelihood. Genetic and LCP analyses indicated that two clades in the northern and southern distribution range have experienced two differing dispersal routes. The newts identified through the northern populations with high genetic diversity have dispersed with stepping-stone movements. In contrast, the southern populations are more isolated and dispersal might be facilitated by aquatic corridors in the least cost slope. We suggest that this study allows new implications for the conservation priorities of N. kaiseri by estimating the potential dispersal activity of the species in the face of climate change and ongoing habitat destruction relating to human activities in the southern Zagros mountains of Iran.

Effect of land use, habitat suitability, and hurricanes on the population connectivity of an endemic insular bat

Urbanization and natural disasters can disrupt landscape connectivity, effectively isolating populations and increasing the risk of local extirpation particularly in island systems. To understand how fragmentation affects corridors among forested areas, we used circuit theory to model the landscape connectivity of the endemic bat Stenoderma rufum within Puerto Rico. Our models combined species occurrences, land use, habitat suitability, and vegetation cover data that were used either as resistance (land use) or conductance layers (habitat suitability and vegetation cover). Urbanization affected connectivity overall from east to west and underscored protected and rustic areas for the maintenance of forest corridors. Suitable habitat provided a reliable measure of connectivity among potential movement corridors that connected more isolated areas. We found that intense hurricanes that disrupt forest integrity can affect connectivity of suitable habitat. Some of the largest protected areas in the east of Puerto Rico are at an increasing risk of becoming disconnected from more continuous forest patches. Given the increasing rate of urbanization, this pattern could also apply to other vertebrates. Our findings show the importance of maintaining forest integrity, emphasizing the considerable conservation value of rustic areas for the preservation of local biodiversity.

Potential Movement Corridors and High Road-Kill Likelihood do not Spatially Coincide for Felids in Brazil: Implications for Road Mitigation.

The negative effects of roads on wildlife populations are a growing concern. Movement corridors and road-kill data are typically used to prioritize road segments for mitigation measures. Some research suggests that locations where animals move across roads following corridors coincide with locations where they are often killed by vehicles. Other research indicates that corridors and road-kill rarely occur in the same locations. We compared movement corridor and road mortality models as means of prioritizing road segments for mitigation for five species of felids in Brazil: tiger cats (Leopardus tigrinus and Leopardus guttulus were analyzed together), ocelot (Leopardus pardalis), jaguarundi (Herpailurus yagouaroundi), and puma (Puma concolor). We used occurrence data for each species and applied circuit theory to identify potential movement corridors crossed by roads. We used road-kill records for each species and applied maximum entropy to determine where mortality was most likely to occur on roads. Our findings suggest that movement corridors and high road mortality are not spatially associated. We suggest that differences in the behavioral state of the individuals in the species occurrence and road-kill data may explain these results. We recommend that the road segments for which the results from the two methods agree (~5300 km for all studied species combined at 95th percentile) should be high-priority candidates for mitigation together with road segments identified by at least one method in areas where felids occur in low population densities or are threatened by isolation effects.

Habitat selection by a threatened desert amphibian.

Habitat degradation and fragmentation are major drivers of amphibian declines. The loss of environmental features that allow for movement between water sources may be particularly detrimental for amphibians in arid environments. Climate changes will increase the importance of microhabitats to amphibians. Enhancing areas to facilitate movement may be a necessary conservation strategy for many animal species that depend on wetlands, including federally threatened Chiricahua leopard frogs (Lithobates chiricahuensis). Habitat preferences of this frog species are not well understood. We sought to better understand fine‐scale habitat selection, to inform conservation of Chiricahua leopard frogs.We conducted our study on the Ladder Ranch, a privately owned working bison ranch in New Mexico, USA that supports a large proportion of the remaining Chiricahua leopard frogs in the state.We attached radio transmitters to 44 frogs during summer 2014. We located each frog daily for up to 8 weeks (median = 30 days). We assessed fine‐scale habitat selection by comparing characteristics at each frog location and a random location 5 m away using conditional logistic regression.Frogs preferred features that likely reduce desiccation, even after accounting for the presence of water. Frogs selected areas with more low‐lying cover, especially aquatic vegetation and woody debris, a tree overstory, and a mud substrate.We recommend managing potential movement corridors for Chiricahua leopard frogs by ensuring the presence of muddy creek bottoms, woody debris, riparian overstory, low‐lying ground cover, and pools. Microclimates created by these features seem especially valuable given warming temperatures and modified precipitation regimes, resulting in decreased surface water, soil moisture, and vegetation cover. Retaining or creating preferred habitat features and microclimates in areas between water sources may increase connectivity among isolated populations of Chiricahua leopard frogs and could improve persistence and recovery of other water‐obligate species in arid landscapes.

Multiscale landscape genetics of American marten at their southern range periphery

American marten (Martes americana) are a conservation priority in many forested regions of North America. Populations are fragmented at the southern edge of their distribution due to suboptimal habitat conditions. Facilitating gene flow may improve population resilience through genetic and demographic rescue. We used a multiscale approach to estimate the relationship between genetic connectivity and landscape characteristics among individuals at three scales in the northeastern United States: regional, subregional, and local. We integrated multiple modeling techniques and identified top models based on consensus. Top models were used to parameterize resistance surfaces at each scale, and circuit theory was used to identify potential movement corridors. Regional gene flow was affected by forest cover, elevation, developed land cover, and slope. At subregional and local scales, the effects were site specific and included subsets of temperature, elevation, developed land cover, and slope. Developed land cover significantly affected gene flow at each scale. At finer scales, lack of variance in forest cover may have limited the ability to detect a relationship with gene flow. The effect of slope on gene flow was positive or negative, depending on the site examined. Occupancy probability was a relatively poor predictor, and we caution its use as a proxy for landscape resistance. Our results underscore the importance of replication and multiscale approaches in landscape genetics. Climate warming and landscape conversion may reduce the genetic connectivity of marten populations in the northeastern United States, and represent the primary challenges to marten conservation at the southern periphery of their range.

Paradigm and pragmatism: GIS‐based spatial analyses of Roman infrastructure networks and land‐use concepts in the Upper Rhine Valley

AbstractThe Roman infrastructural network in the Upper Rhine Valley aligns with the locations of military fortifications and also connects agricultural areas and settlements to trade routes and regional markets. Conventionally, the connection of rural areas to these broader networks is imagined as a straight line, suggesting direct connectivity, maximum accessibility, and engineering pragmatism. However, it is important to appreciate that local environmental conditions had a strong impact on Roman road development and land‐use strategies. This article examines the geomorphological, geological, and hydrogeological conditions in the Upper Rhine Valley to define and analyze the relationships between Roman transport routes, settlement, and land‐use opportunities, and physical‐geographical factors. An accumulative cost surface is generated using vegetation data based on satellite imagery, and attributes are recorded in geomorphological and geological maps in a GIS. This modeling technique leads to potential movement and infrastructure corridors. Topographical aspects and terrain roughness play only a minor role in the study area, and it is argued that the interplay of aquifer thickness, groundwater level, quaternary sedimentology, and soil communities is decisive for assessing the suitability of terrain for corridors of movement.

A potential habitat corridor for Western Purple-faced Langur between Forest Reserves in Sri Lanka: GIS as a tool in connectivity modelling

Endemic Western purple-faced langur (Semnophithecus vetulus nestor) of Sri Lanka, is an exclusively arboreal, critically endangered primate whose habitats are severely fragmented with the human population expansion. Labugama-Kalatuwawa Forest Reserve (LKFR) which is identified as the last strongholds for maintaining viable populations of the species over the long-run and Indikada Mukalana Forest Reserve (IMFR) which is located in a closer proximity to LKFR have no connection with each other at the current status. As there is no assertion of regional habitat connectivity at a metapopulation context, the study aimed to identify a potential habitat corridor for S. v. nestor between LKFR and IMFR by using GIS as a tool in connectivity modelling. Study area was first divided into 0.04 km2 grids using ‘fishnet’ tool. Five main resistance criteria for S. v. nestor movement were selected namely; land use, road density, canopy cover, human tolerance and Feeding Plant Species Richness and Density (FPSRD). Each grid was assigned with resistance values for above criteria ranging from 1 to 6. Overall resistance layer for S. v. nestor movement was created using ‘weighted overlay’ in GIS environment. The best potential habitat corridor was identified via least-cost modelling. The resultant corridor falls within an area which mainly comprises of forest and rubber (Hevea brasiliensis) monoculture. It further accounts for the highest human tolerance, canopy continuity, FPSRD and least road density. Resultant corridor can be improved by bridging existing gaps and enriching the corridor habitats which would play an important role in conservation of S. v. nestor by minimizing the isolation of local populations, ensuring the gene flow and maintaining the minimum viable metapopulation in the long run. This study further demonstrates that GIS can be used as an effective tool for least-cost modelling which helps to identify potential wildlife movement corridors at minimum cost.

Trans-boundary conservation of Chiru by identifying its potential movement corridors in the alpine desert of Qinghai-Tibetan Plateau

The alpine ecosystem of Qinghai-Tibet Plateau (QTP) provides the world's largest habitats for the endangered Chiru (Pantholops hodgsonii). Most female Chiru populations are seasonal long-distance migrants, but their migration routes (corridors) remain mysterious on the QTP. Three adjacent nature reserves (i.e. Altun, Kekexili, Qiangtang nature reserves) have been established to protect the endangered ungulate species and their habitats on the QTP, but they are delineated and managed according to the administrative boundaries. In this study, we employed a GIS-based model (i.e., Linkage Mapper tool) to identify potential movement corridors of Chiru according to the principle of Least Cost Path. We also examined the impacts of human activities on the spatial patterns and conservation status of the identified movement corridors of Chiru. Our results indicated that only 66% of the movement corridors for Chiru were captured by the existing reserves, whilst 76% of the corridors were disturbed by human activities with a relatively high overall disturbance index. The human disturbance index within the existing reserves was considerably lower than that outside the reserves, indicating the conservation efficacy of the reserves. This research developed the conservation strategy for different categories of the corridors (inside, outside, inter-reserve, opening) for Chiru considering their spatial relationship with the existing nature reserves, and highlighted urgent needs to implement trans-boundary conservation strategy by protecting those corridors connecting the existing nature reserves across the alpine desert of QTP.

Finding Vanished Routes: Applying a Multi-modelling Approach on Lost Route and Path Networks in the Veluwe Region, the Netherlands

Route networks are influenced by cultural and environmental dynamics. Consequently, route networks themselves often are dynamic as well. This is especially true in lowland areas, such as the Netherlands, where environmental processes (e.g. geomorphological changes, floods) probably reshaped these networks numerous times. Many of the existing route networks in the Netherlands were established relatively recently, and little is known of their historical predecessors. Recent developments in spatial modelling may improve locating and analysing these old, vanished routes. In this study we have applied two recently-developed applications for historical-route network modelling to the Veluwe (the Netherlands) in order to reconstruct the route network in the region around AD 1500. This region is not densely cultivated and is known to have a long history of routes and paths running through the landscape. The first method, network friction, uses high-resolution geoscientific and cultural data to calculate potential movement corridors and probable route zones. The second method uses a more traditional least-cost path (LCP) model based on surface, groundwater level and slope. The usefulness of these approaches for reconstructing past route networks and the general added value of these approaches was assessed by comparing the reconstructions to the few existing spatial overviews of historical-route networks in this region and hollow ways extracted from Airborne Laser Scanning (ALS) data. Our findings show that the results of the first method, network-friction modelling, correspond best with the comparison data regarding known routes in the study area. However, the general results point towards the necessity of integrating the two applied methods, since a combination of these models best reflects the multiscale variability within regional route networks.

Does one size fit all? A multispecies approach to regional landscape corridor planning

AbstractAimThe practical value of the single‐species approach to conserve biodiversity could be minimal or negligible when sympatric species are limited by factors that are not relevant to the proposed umbrella species. In this study, we quantitatively evaluated as follows: (1) habitat suitability and potential movement corridors of a single umbrella species, giant panda (Ailuropoda melanoleuca); (2) habitat suitability of sympatric mammals; and (3) the potential effectiveness of the single‐species corridor planning to preserve suitable habitat and its connectivity of other focal species.LocationQinling Mountains, central part of China (15,000 km2).MethodsWe collected species distribution, environmental and anthropogenic data and conducted species occupancy modelling for giant panda and six other sympatric species (i.e., takin Budorcas taxicolor, tufted deer Elaphodus cephalophus, Chinese goral Naemorhedus griseus, Reeve's muntjac Muntiacus reevesi, leopard cat Prionailurus bengalensis and yellow‐throated marten Martes flavigula). We then conducted circuit models to identify potential corridors for each species and evaluated the effectiveness of giant panda corridors to restore the habitat connectivity for these sympatric mammals.ResultsOccupancy modelling revealed that each species had a unique set of environmental variables associated with its distribution in the Qinling Mountains. We found that giant panda and all other focal species had some degree of fragmentation to their suitable habitat that required restoring habitat connectivity. Among the eight potential giant panda corridors, conservation efforts to reduce anthropogenic impacts would significantly improve the effectiveness of six corridors, while the other two corridors would require altering the vegetation. Five proposed giant panda corridors had remarkable overlap with corridors proposed for other species. We suggest two giant panda corridors as a priority due to their potential to maximize the benefits to both giant panda and a broader suite of mammals.Main conclusionsCorridor planning in this region of China will likely continue using the single‐species policy, but our results highlight that not all potential giant panda corridors have equal effectiveness for other wildlife species. When offered multiple alternative actions, conservation planners can prioritize corridor development based on a multispecies perspective without loss of connectivity for the priority species. This approach has strong implications to the conservation of wildlife communities in China, and elsewhere, where conservation plans developed for a single‐species garner most available funding and institutional support.

Mitigation reduces road mortality of a threatened rattlesnake

Context Reducing road mortality is essential to reptile conservation in regions with dense road networks. The Georgian Bay, Ontario population of the eastern massasauga rattlesnake (Sistrurus catenatus) is designated as Threatened, in part because of high road mortality. In Killbear Provincial Park, four ecopassages and barrier fencing were constructed along three busy park roads to reduce road mortality of massasaugas. Aim Although mitigation of road mortality has been widely recommended and in some instances implemented for reptiles, effectiveness of mitigation efforts is often inadequately evaluated. The goals of our study were to use long-term data to quantify the effectiveness of ecopassages and barrier fencing in reducing massasauga fatalities on roads, and to evaluate the potential of these structures to serve as movement corridors for individual snakes. Methods We used five approaches to assess the overall efficacy of mitigation efforts: (1) comparison of pre- and post-mitigation road mortality; (2) camera traps in ecopassages to document massasauga and predator presence; (3) automated tag readers in ecopassage entrances to detect PIT-tagged individuals; (4) an experiment to assess massasauga willingness to enter and travel through ecopassages; and (5) measurement of temperature fluctuations in ecopassages to assess thermal suitability for massasaugas. Key results We found a significant decrease in road mortality of massasaugas on stretches of park roads associated with ecopassages and barrier fencing post construction. Automated tag readers and cameras detected the presence of massasaugas and other animals within the ecopassages, and experimental data showed that massasaugas willingly entered, and in some cases crossed through, ecopassages. Conclusion Our evaluation of mitigation structures determined that they successfully reduce road mortality and provide potential movement corridors between bisected habitats, provided that intense maintenance of the fencing is conducted yearly. We also demonstrated the need to utilise a combination of multiple post-monitoring methods to effectively evaluate mitigation structures. Implications This study provides a template for construction of similar mitigation in other key locations where reptile road mortality occurs.

Use of least-cost path analysis to identify potential movement corridors of swift foxes in Montana

The swift fox ( Vulpes velox ) is a small grassland canid native to the North American Great Plains. A reintroduced swift fox population in Canada and northern Montana appears to be isolated from those existing in the central and southern Great Plains. We developed a swift fox habitat suitability model for southeastern Montana, the region between the 2 populations. The resulting model indicated that 67.9% of the study area consisted of highly suitable habitat. We conducted a least-cost path analysis to evaluate the connectivity of swift fox habitat in the study area to existing swift fox populations in the region. We identified a potential dispersal corridor through southeastern Montana that could facilitate movement between swift fox populations in northern Montana and northern Wyoming and identified 4 prairie dog complexes in Rosebud, Custer, and Powder River Counties, Montana, that could serve as potential swift fox reintroduction sites. Each site comprised several prairie dog colonies in close proximity and encompassed ≥ 95 km2. We evaluated the effect that swift fox populations established in each potential reintroduction site could have on population connectivity. Our results as well as future surveys could inform swift fox management and reintroduction programs in Montana.

Assessing differences in connectivity based on habitat versus movement models for brown bears in the Carpathians

Connectivity assessments typically rely on resistance surfaces derived from habitat models, assuming that higher-quality habitat facilitates movement. This assumption remains largely untested though, and it is unlikely that the same environmental factors determine both animal movements and habitat selection, potentially biasing connectivity assessments. We evaluated how much connectivity assessments differ when based on resistance surfaces from habitat versus movement models. In addition, we tested how sensitive connectivity assessments are with respect to the parameterization of the movement models. We parameterized maximum entropy models to predict habitat suitability, and step selection functions to derive movement models for brown bear (Ursus arctos) in the northeastern Carpathians. We compared spatial patterns and distributions of resistance values derived from those models, and locations and characteristics of potential movement corridors. Brown bears preferred areas with high forest cover, close to forest edges, high topographic complexity, and with low human pressure in both habitat and movement models. However, resistance surfaces derived from the habitat models based on predictors measured at broad and medium scales tended to underestimate connectivity, as they predicted substantially higher resistance values for most of the study area, including corridors. Our findings highlighted that connectivity assessments should be based on movement information if available, rather than generic habitat models. However, the parameterization of movement models is important, because the type of movement events considered, and the sampling method of environmental covariates can greatly affect connectivity assessments, and hence the predicted corridors.

Urban land use does not limit weaver bird movements between wetlands in Cape Town, South Africa

Urbanisation often has profound impacts on ecological processes. Management of these impacts is central to urban conservation efforts. We used data from 6591 individually ringed weaver birds from 42 ringing locations to investigate the influence that the urban matrix, as well as patch isolation, size and quality, had on weaver bird movement between ringing locations in Cape Town, a growing city within a global biodiversity hotspot. Distance-based linear models revealed that proximity to other sites was the dominant predictor of weaver movement while the site variables (wetland size and bird abundance) had a limited and inconclusive influence. Once the variation explained by the proximity and site variables had been accounted for, the composition of the surrounding urban matrix, the length of the least cost path between wetlands, and the presence of rivers as potential movement corridors (measured at three spatial scales) all had little influence on weaver movement. Analysis of the weaver bird movement-wetland network using social network analysis showed that the network is simple, clustered, and non-random, with relatively high vulnerability to node loss and some indication of preferential attachment (i.e., increased use of more used sites). Since proximity (site isolation) is the dominant influence on weaver movements, and the network is already sparse, further wetland loss is likely to reduce population viability. Our results match the predictions of classical theory and suggest that patch management will matter more for wetland passerines than matrix management.

Estimating effective landscape distances and movement corridors: comparison of habitat and genetic data

Resistance models provide a key foundation for landscape connectivity analyses and are widely used to delineate wildlife corridors. Currently, there is no general consensus regarding the most effective empirical methods to parameterize resistance models, but habitat data (species' presence data and related habitat suitability models) and genetic data are the most widely used and advocated approaches. However, the practical consequences of applying one or the other approach have not been well studied. To address this knowledge gap, we performed a comparative study on the implications of using habitat suitability versus genetic data for determining effective landscape distances (a proxy inversely related to isolation among patches) based on least‐cost and circuit‐theoretic approaches, and for identifying potential movement corridors. For our comparison, we used data for the Cantabrian brown bear in Spain, an endangered population for which connectivity has been identified as a major conservation concern. Our results show that for brown bears, habitat models tend to overestimate resistance to movement through non‐optimal areas, whereas genetic data yield higher estimates of effective distances within habitat areas. Therefore, our results suggest that (1) dispersal might be generally less constrained by landscape conditions than habitat utilization in home ranges, and that (2) dispersing animals might be more flexible in their movement behavior than residents are in their habitat resource utilization behavior, with records for residents dominating species occurrence data and subsequent habitat models. The assessed approaches provided dissimilar connectivity models with notable differences in patterns of predicted corridors across the study area, mainly due to differences in predicted connections between subpopulations. Our results highlight that the functional differences in habitat vs. genetic data, as well as the assumptions and potential limitations of different analytical approaches that use these data, need to be considered more carefully in connectivity modeling and subsequent corridor delineation.