Habitat Networks Research Articles

An equitable method for evaluating habitat amount and potential occupancy

Landscape connectivity measures based on metapopulation theory were developed over 20 years ago. Initially, they applied classic metapopulation models to simple patch-based representations of landscapes using vector spatial data structures. Realism was improved by developing dynamic estimates of occupancy and metapopulation capacity, the latter providing a measure of the integrated habitat amount. Such measures are used to estimate the ability of habitat networks to support metapopulation persistence. The original methods for occupancy mapping and metapopulation capacity were adapted to work with fine-grained, continuous-value raster data. That step shifted the method outside of the classic metapopulation model which left some methodological issues unresolved; in particular, what has been termed the deceptive paradox of patch-based connectivity whereby perverse and what we describe as inequitable results are obtained through arbitrary circumscription of the analysis grid and through the trading of habitat between habitat quality, extent and connectivity. We provide a solution to this issue and apply it within the frame of Drielsma and Ferrier's (2009) raster-based Rapid Evaluation of Metapopulation Persistence (REMP).We demonstrate our solution using simple hypothetical examples; and in order to demonstrate the practicality of our approach to real-world settings, we apply the approach to habitat suitability mapping of the White-browed Treecreeper (Climacteris affinis) in south eastern New South Wales, Australia.

Restoring farmlands for food and nature

Changes in the intensity and extent of farmland have a profound impact on life on Earth. Although nature-rich farmlands have conservation value, their promotion competes with the protection and restoration of natural habitat. Restoring the productive capacity of existing farmland can help maximize opportunities for the restoration of both nature-rich farmlands and natural habitat.

Species-habitat networks elucidate landscape effects on habitat specialisation of natural enemies and pollinators.

Measuring habitat specialisation is pivotal for predicting species extinctions and for understanding consequences on ecosystem functioning. Here, we sampled pollinator and natural enemy communities in all major habitat types occurring across multiple agricultural landscapes and used species-habitat networks to determine how habitat specialisation changed along gradients in landscape composition and configuration. Although it is well known that landscape simplification often causes the replacement of specialists with generalists, our study provided evidence for intraspecific variation in habitat specialisation, highlighting how a large number of arthropod species adapted their way of selecting habitat resources depending on the landscape structure. Groups with higher diet specialisation and limited foraging flexibility appeared to have a reduced ability to respond to landscape changes, indicating that some arthropod taxa are better able than others to adapt to an increasingly broad set of resources and persist in highly impacted landscapes.

Indicators for assessing the robustness of metapopulations against habitat loss

Habitat loss and fragmentation resulting from environmental changes are main drivers of global biodiversity loss, as the survival of metapopulations relies on the ability of individuals to disperse among suitable habitat patches. To prioritize conservation efforts, methods are needed for evaluating the robustness of metapopulations against habitat loss. We therefore investigate this robustness for different degrees of habitat loss, for different types of habitat loss (random, peripheral, and contagious) and of habitat networks, and for species differing in their local-extinction risks and dispersal ranges. In particular, we analyse several standard network types (with random, regular, small-world, or scale-free structure) and compare them with several alternative network types derived from real-world two-dimensional habitat landscapes (with random, clustered, or contiguous habitat allocation). Furthermore, we investigate how well 29 different graph-theoretic metrics of habitat networks can serve as indicators of metapopulation robustness against habitat loss – as this approach, where feasible, allows replacing complex simulation-based predictions with simple indicator-based predictions. We find that responses of species to habitat loss on the considered landscape-based habitat networks qualitatively differ from those on the considered standard habitat networks. This suggests that results obtained for the latter, albeit widely examined in the literature, can be unrepresentative and misleading. As expected, species with high risks of local extinction and short dispersal ranges are particularly vulnerable to habitat loss, across all considered types of habitat loss and habitat networks. The graph-theoretic network metric that best explains the robustness of metapopulations against habitat loss depends on the considered types of species, habitat networks, and habitat loss. None of the examined metrics give consistently reliable predictions under all circumstances. For sensitive species, characterized by high local-extinction risks and short dispersal ranges, a network’s average clique size, redundancy, average degree, connectance, clustering coefficient, and average closeness centrality are the best indicators of metapopulation robustness. For landscape-based habitat networks, a network’s average clique size, beta coefficient, clustering coefficient, redundancy, and cyclomatic number work best. For contagious habitat loss, the network type has a particularly strong impact on the species-specific robustness against habitat loss. In summary, our study introduces a method for evaluating the robustness of metapopulations against habitat loss and shows that a network’s clustering coefficient, under a wide range of circumstances, is a particularly reliable indicator of this robustness.

Effects of drought on the abundance and distribution of non-breeding shorebirds in central California, USA

Conservation of migratory species requires anticipating the potential impacts of extreme climatic events, such as extreme drought. During drought, reduced habitat availability for shorebirds creates the potential for changes in their abundance and distribution, in part because many species are highly mobile and rely on networks of interior and coastal habitats. Understanding how shorebirds responded to a recent drought cycle that peaked from 2013 to 2015 in central California, USA, will help optimize management of wetlands and fresh water for wildlife. In the Central Valley, a vast interior region that is characterized by a mosaic of wetlands and agricultural lands, we found 22% and 29% decreases in the annual abundance of shorebirds during periods of 3-year drought (2013-2015) and 2-year extreme drought (2014-2015), respectively, when compared to non-drought years. Lower abundance of shorebirds coincided with significant decreases in the mean proportion flooded of survey units (7% and 9%, respectively) that were reliant on fresh water. Drought was associated with lower abundance within both the interior Central Valley and coastal San Francisco Bay for greater and lesser yellowlegs (Tringa melanoleuca and T. flavipes) and long- and short-billed dowitchers (Limnodromus scolopaceus and L. griseus). Only dunlins (Calidris alpina) had patterns of abundance that suggested substantial shifts in distribution between the Central Valley and coastal regions of San Francisco Bay and Point Reyes. Our results indicate that drought has the potential to reduce, at least temporally, shorebird populations and flooded habitat in the Central Valley, and the ability to respond to drought by taking advantage of nearby coastal habitats may limit the long-term effects of drought on some species. Successful conservation strategies must balance the impacts of reduced habitat availability at interior sites with the ability of some migratory shorebirds to adapt rapidly to shifting distributions of resources.

Maximising the clustering coefficient of networks and the effects on habitat network robustness.

The robustness of networks against node failure and the response of networks to node removal has been studied extensively for networks such as transportation networks, power grids, and food webs. In many cases, a network’s clustering coefficient was identified as a good indicator for network robustness. In ecology, habitat networks constitute a powerful tool to represent metapopulations or -communities, where nodes represent habitat patches and links indicate how these are connected. Current climate and land-use changes result in decline of habitat area and its connectivity and are thus the main drivers for the ongoing biodiversity loss. Conservation efforts are therefore needed to improve the connectivity and mitigate effects of habitat loss. Habitat loss can easily be modelled with the help of habitat networks and the question arises how to modify networks to obtain higher robustness. Here, we develop tools to identify which links should be added to a network to increase the robustness. We introduce two different heuristics, Greedy and Lazy Greedy, to maximize the clustering coefficient if multiple links can be added. We test these approaches and compare the results to the optimal solution for different generic networks including a variety of standard networks as well as spatially explicit landscape based habitat networks. In a last step, we simulate the robustness of habitat networks before and after adding multiple links and investigate the increase in robustness depending on both the number of added links and the heuristic used. We found that using our heuristics to add links to sparse networks such as habitat networks has a greater impact on the clustering coefficient compared to randomly adding links. The Greedy algorithm delivered optimal results in almost all cases when adding two links to the network. Furthermore, the robustness of networks increased with the number of additional links added using the Greedy or Lazy Greedy algorithm.

Composition, structure and diversity of fish assemblages across seascape types at Príncipe, an understudied tropical island in the Gulf of Guinea (eastern Atlantic Ocean)

Coastal seascapes are often composed of a mosaic of interconnected habitats. Transitions between adjacent habitats are of special relevance to the ecology of many reef-associated organisms. In this study, we tested (i) whether the degree of similarity in the composition and structure of coastal fish assemblages differed between three interconnected seascape types, and (ii) whether differences in taxonomic and phylogenetic diversity of the fish assemblages were consistent between the seascape types. We sampled fish species from diverse habitats in the shallow coastal waters surrounding the island of Príncipe (Gulf of Guinea, eastern Atlantic Ocean), an understudied and remote tropical island. Specifically, video transects were carried out by SCUBA divers at three seascape types: rocky reefs, rocky reef–rhodolith bed transitions, and rocky reef–sandy bottom transitions, to extract presence/absence and ordinal abundance data, across a range of depths (9–31 m), covering the entire perimeter of the island. A total of 71 fish taxa were recorded. Both the composition and structure of the fish assemblages differed between the studied seascapes. The mean number of fish species (taxonomic diversity) was higher on ‘reefs’ than in both the ‘reef–rhodolith bed’ and ‘reef–sandy bottom’ transitions. In contrast, the taxonomic distinctness index (phylogenetic diversity) was higher for fish assemblages in both transitional seascape types than on rocky reefs. Hence, at the island-scale, the protection of local fish assemblages needs to consider a representative network of interconnected habitats, including at these seascapes boundaries where important ecological functions seem to occur.

Land-use legacies of twentieth-century forestry in the UK: a perspective

ContextComplex interactions between societies and their environment have shaped landscapes across Europe over centuries. Therefore, taking a historical perspective can be important when designing new forestry policy and management activities.ObjectivesThis perspective aims to improve our appreciation of how a better historical understanding of landscapes can increase our understanding of current conditions and inform current and future policy and practice. I provide a perspective on land-use legacies and forest change, with a particular emphasis on landscapes, and using the example of forestry in the United Kingdom.MethodsFor this purpose, I undertook a comprehensive review of scholarly forestry literature and of relevant policy and legal documents in the UK, covering the last 100 years.ResultsThis brief review of the dynamics of forest landscapes in the UK over the last 100 years, shows that certain decisions, policies and management activities had major effects on the landscape, especially in terms of landscape patterns and species distribution, constraining it until today. Historic research investigated some of these legacies, leading to real change in policy and management, including a Broadleaved Policy, an Ancient Woodland Inventory, habitat restoration, habitat network and rewilding schemes. Research on past experiences of Dutch Elm disease in the UK and of similar outbreaks in other countries have guided responses to today’s tree pest/disease outbreaks and plant trade decisions.ConclusionA better appreciation of past decisions and activities, especially in forestry, helps to anticipate landscape legacy effects and potential cross-scale interactions of new policies and practices. It may also help to better justify and negotiate new decisions and long-term planning among multiple actors.

Linking wilderness mapping and connectivity modelling: A methodological framework for wildland network planning

Habitat fragmentation is one of the key drivers of global biodiversity loss. In this context, connectivity modelling is increasingly important for effective conservation. Most previous studies on connectivity modelling are based on focal species, while fewer studies focus on models based on landscape naturalness or wildness. We propose a methodological framework for wildland network planning, which utilizes the results from wilderness mapping as input data for connectivity models. The least-cost model and circuit model are applied using Linkage Mapper and Circuitscape, with wilderness areas selected as source patches together with resistance values transformed from a wilderness quality index. Taking the Great Taihang region of China as an example, wildland networks are created and pinch-points are identified. We show that the selection of core patches and resistance surfaces have a significant impact on the resulting corridors. The wildland network could serve as an effective and efficient alternative to habitat network and supplement the protected areas network, especially when the species distribution data are lacking, or a rapid assessment is required. This framework for wildland planning could potentially be applied to fragmented landscapes across various countries to eliminate or reduce the negative impacts of habitat fragmentation on biodiversity.

Monitoring Urban Green Infrastructure Changes and Impact on Habitat Connectivity Using High-Resolution Satellite Data

In recent decades, the City of Stockholm, Sweden, has grown substantially and is now the largest city in Scandinavia. Recent urban growth is placing pressure on green areas within and around the city. In order to protect biodiversity and ecosystem services, green infrastructure is part of Stockholm municipal planning. This research quantifies land-cover change in the City of Stockholm between 2003 and 2018 and examines what impact urban growth has had on its green infrastructure. Two 2018 WorldView-2 images and three 2003 QuickBird-2 images were used to produce classifications of 11 land-cover types using object-based image analysis and a support vector machine algorithm with spectral, geometric and texture features. The classification accuracies reached over 90% and the results were used in calculations and comparisons to determine the impact of urban growth in Stockholm between 2003 and 2018, including the generation of land-cover change statistics in relation to administrative boundaries and green infrastructure. For components of the green infrastructure, i.e., habitat networks for selected sensitive species, habitat network analysis for the European crested tit (Lophophanes cristatus) and common toad (Bufo bufo) was performed. Between 2003 and 2018, urban areas increased by approximately 4% while green areas decreased by 2% in comparison with their 2003 areal amounts. The most significant urban growth occurred through expansion of the transport network, paved surfaces and construction areas which increased by 12%, mainly at the expense of grassland and coniferous forest. Examination of urban growth within the green infrastructure indicated that most land area was lost in dispersal zones (28 ha) while the highest percent change was within habitat for species of conservation concern (14%). The habitat network analysis revealed that overall connectivity decreased slightly through patch fragmentation and areal loss mainly caused by road expansion on the outskirts of the city. The habitat network analysis also revealed which habitat areas are well-connected and which are most vulnerable. These results can assist policymakers and planners in their efforts to ensure sustainable urban development including sustaining biodiversity in the City of Stockholm.

Cross-scale connectivity of macrobenthic communities in a patchy network of habitats: The Mesophotic Biogenic Habitats of the Northern Adriatic Sea

Connectivity is a fundamental ecological property affecting stability, resilience and recovery of marine populations, in particular in networks of patchy habitats as the Mesophotic Biogenic Habitats of the Northern Adriatic Sea. Specific information on the dispersal behaviour of many species living in these habitats is lacking, thus the connectivity simulations were performed over different pelagic propagules duration and different reproductive seasons of six consecutive years, covering most of the possible dispersal behaviour variability. The connectivity simulations were analysed with graph analysis methods by characterizing each connectivity graph with several structural measures and by identifying sites with greatest individual and group centrality. We tested the hypothesis that geographic proximity of sites cannot be a proxy for the connectivity and that hydrodynamic connectivity is statistically significantly related to the observed beta diversity among the studied sites. Results showed that species with different pelagic propagules duration follow greatly different dispersal dynamics, and that the network of studied outcrops is only partially connected to coastal benthic populations. Our results also made possible a critical appraisal of the current conservation strategies, evidencing gaps in the existing network of protected Mesophotic Biogenic Habitats in the Northern Adriatic Sea. We suggest possible improvements for an efficient preservation strategy of these unique biodiversity hotspots by including a fundamental ecological process, the dispersal connectivity, into the process of decision making for conservation.

Simulation modeling reveals the evolutionary role of landscape shape and species dispersal on genetic variation within a metapopulation

Different shapes of landscape boundaries can affect the habitat networks within them and consequently the spatial genetic‐patterns of a metapopulation. In this study, we used a mechanistic framework to evaluate the effects of landscape shape, through watershed elongation, on genetic divergence among populations at the metapopulation scale. Empirical genetic data from four, sympatric stream‐macroinvertebrates having aerial adults were collected from streams in Japan to determine the roles of species‐specific dispersal strategies on metapopulation genetics. Simulation results indicated that watershed elongation allows the formation of river networks with fewer branches and larger topographic constraints. This results in decreased interpopulation connectivity but a lower level of spatial isolation of distal populations (e.g. those found in headwaters) occurring in the landscapes examined. Distal populations had higher genetic divergence when their downstream‐biased dispersal (relative to upstream‐ and/or overland‐biased dispersal) was high. This underscores the importance of distal populations influencing genetic divergence at the metapopulation scale for species having downstream‐biased dispersal. In turn, lower genetic divergence was observed under watershed elongation when the genetic isolation of distal populations was decreased in such species. This strong association between landscape shape and evolutionary processes highlights the importance of natural, spatial architecture in assessing the effectiveness of conservation and management strategies.

Mobility, habitat selection and population connectivity of the butterfly Lycaena helle in central Sweden

To be able to predict habitat quality and potential distribution of threatened species is key to developing successful conservation strategies for threatened species with fragmented distributions. The aim of this study was to assess factors that limit the local distribution and density of Lycaena helle, an endangered butterfly, in central Sweden, and to estimate its mobility in order to classify local populations according to their importance for the connectivity on a regional level. An additional aim was to test if L. helle habitat quality could be assessed using remotely-sensed data such as laser scanning (LiDAR). We derived potential predictors of L. helle occurrence from laser scanning data and used a resource selection function to assess their predictive power. We used a mark-recapture approach to study L. helle movement and estimate dispersal distances. The probability of occurrence of L. helle increased with higher solar irradiation and was negatively affected by sloping terrain, but the LiDAR data generally had low predictive power. Population density increased with host plant density, but this effect was weak. The mark-recapture study confirmed that L. helle is very sedentary, with a mean movement distance of only 114 m and a maximum of 600 m. The studied population extends over a large network of interconnected linear habitats, which probably facilitates dispersal and thereby population persistence. Our study highlight the importance of a warm micro-climate and of man-made habitats like road verges and power-line corridors for the conservation of L. helle.

Preserving connectivity under climate and land-use change: No one-size-fits-all approach for focal species in similar habitats

Habitat connectivity is essential for maintaining populations of wildlife species, especially as climate changes. Knowledge about the fate of existing habitat networks in a changing climate and in light of land-use change is critical for determining which types of conservation actions must be taken to maintain those networks. However, information is lacking about how multiple focal species that use similar habitats overlap in the degree and geographic patterns of threats to linkages among currently suitable habitat patches. We sought to address that gap. We assessed climate change threat to existing linkages in the southeastern United States for three wildlife species that use similar habitats but differ in the degree to which their ranges are limited by climate, habitat specificity, and dispersal ability. Linkages for the specialist species (timber rattlesnake), whose range is climate-restricted, were more likely to serve as climate change refugia – that is, they were more likely to be climate-stable – by the middle of the 21st century. This contrasts with the two more generalist species (Rafinesque's big-eared bat and American black bear), whose linkages were threatened by climate change and thus required adaptation measures. Further incorporation of projected land-use change and current protection status for important linkages narrows down our recommended conservation actions for each species. Our results highlight the surprising ways in which even species that use similar habitats will experience differences in the degree and geographic patterns of threats to connectivity. Taking action before these projected changes occur will be critical for successful conservation.

Mapping connectivity and conflict risk to identify safe corridors for the Persian leopard

ContextMany large carnivores depend on habitat patches outside protected areas, as well as safe corridors between them. However, corridor assessments typically ignore potential conflicts between carnivores and people, which can undermine corridor effectiveness and thus conservation success.ObjectivesWe identified safe dispersal corridors and conflict-prone movement bottlenecks for Persian leopard (Panthera pardus saxicolor) between protected areas in the Alborz Mountains, Iran, by mapping habitat, landscape permeability, and conflict risk. We then identified priority areas for conservation interventions according to the intensities of different threats.MethodsWe mapped land cover using Landsat satellite images, gathered data on leopard and prey distributions and livestock depredation events via interview surveys in 69 cells of 6 × 6 km each. We then used occupancy modeling to identify habitat patches, used circuit theory modeling to analyze landscape permeability, and assessed human-leopard conflict risk using generalized linear models.ResultsLeopard habitat use increased with prey availability and decreased with elevation. Prey distribution, in turn, was mostly negatively influenced by agricultural lands and distance from protected areas. Conflict risk (i.e., probability of leopard depredation on livestock) was high in landscapes where agriculture was widespread and historical forest loss high. Not accounting for conflicts overestimated connectivity among habitat patches substantially.ConclusionsHuman-carnivore conflicts are an important constraint to connectivity and should be considered in corridor assessments. Our study shows how habitat analysis, connectivity assessment, and conflict risk mapping can be combined to guide conservation planning for identifying habitat networks and safe corridors for carnivores in human-dominated landscapes.

<p class="Body"><strong>Network structure of interactions between phytophagous mites and their host-plants in natural ecosystems in Brazil</strong></p>

Phytophagous mites represent a diverse group of Arachnida, however, the patterns of their interactions with their host plants remain little explored. Herein we compare structural patterns of plant-phytophagous mite networks of forest and open habitats in Brazil. We adopted network size, network connectance and network modularity to characterize plant-mite network structure. We analyzed 11 plant-mite networks composed by 106 mite species, 96 host-plant species, and 342 distinct interactions. Tetranychidae and Eriophyidae were the most speciose mite families while Euphorbiaceae and Fabaceae were the most relevant host-plant families, hosting 67 and 16 mite species, respectively. We did not find any differences in network size and modularity between biomes and habitat types. However, network connectance was lower for open vegetation habitats than for forest habitat networks. Open areas can constrain the selection of defensive traits by plant species, leading phytophagous mites to consume plant species more selectively, which generates low connectivity in networks of these environments. The small number of plant-mite networks described here highlights the need for more efforts to increase knowledge about plant mites in Brazilian natural vegetation.

Habitat network topology influences the importance of ecological traps in metapopulations

AbstractThe majority of species exist in metapopulations, where populations are linked to one another through dispersal. Disturbances (natural or anthropogenic) are known to affect population vital rates which can reverberate to the metapopulations through dispersal, which is determined by the topology of the habitat network (i.e., the number of patches and their spatial layout). Within a habitat network, disturbed patches become sinks or ecological traps depending on whether individuals avoid or are attracted to the disturbed patch. Ecological traps occur when individuals preferentially disperse to patches that result in low fitness which can have severe consequences for metapopulations. However, the effects of ecological traps should be considered relative to a number of factors, such as the number of disturbed patches, the fitness cost of the disturbance, and dispersal. Further, the relative importance of each factor can vary among different habitat network topologies according to the position and role of the disturbed patches for maintaining the functional connectivity of the entire metapopulation. Using a spatially explicit stochastic stage‐based metapopulation model based on amphibian life history, we investigate how the number of disturbed patches, fitness cost of the disturbance, dispersal rate, and attractiveness of disturbed habitat patches affect the persistence of metapopulations in different habitat network topologies (random, tree, and full). Overall, dispersal, the number of disturbed patches, and the fitness penalty of the disturbance were the most important factors affecting mean metapopulation growth rate, the probability of extinction, and time to extinction. Ecological traps had the largest effect in the tree network topology where the number of links between patches was limited. For all network topologies studied, larger negative effects were observed when disturbed patches were centrally located in the network. Reducing the number and spatial correlation of disturbances is known to be a reliable conservation strategy, we add the importance of considering the location of disturbances within habitat networks and network topology.

Enhanced shrub growth in the Arctic increases habitat connectivity for browsing herbivores.

Habitat connectivity is a key factor influencing species range dynamics. Rapid warming in the Arctic is leading to widespread heterogeneous shrub expansion, but impacts of these habitat changes on range dynamics for large herbivores are not well understood. We use the climate-shrub-moose system of northern Alaska as a case study to examine how shrub habitat will respond to predicted future warming, and how these changes may impact habitat connectivity and the distribution of moose (Alces alces). We used a 19year moose location dataset, a 568km transect of field shrub sampling, and forecasted warming scenarios with regional downscaling to map current and projected shrub habitat for moose on the North Slope of Alaska. The tall-shrub habitat for moose exhibited a dendritic spatial configuration correlated with river corridor networks and mean July temperature. Warming scenarios predict that moose habitat will more than double by 2099. Forecasted warming is predicted to increase the spatial cohesion of the habitat network that diminishes effects of fragmentation, which improves overall habitat quality and likely expands the range of moose. These findings demonstrate how climate change may increase habitat connectivity and alter the distributions of shrub herbivores in the Arctic, including creation of novel communities and ecosystems.

Contribution of Connectivity Assessments to Green Infrastructure (GI)

A major goal of green infrastructure (GI) is to provide functional networks of habitats and ecosystems to maintain biodiversity long-term, while at the same time optimizing landscape and ecosystem functions and services to meet human needs. Traditionally, connectivity studies are informed by movement ecology with species-specific attributes of the type and timing of movement (e.g., dispersal, foraging, mating) and movement distances, while spatial environmental data help delineate movement pathways across landscapes. To date, a range of methods and approaches are available that (a) are relevant across any organism and movement type independent of time and space scales, (b) are ready-to-use as standalone freeware or custom GIS implementation, and (c) produce appealing visual outputs that facilitate communication with land managers. However, to enhance the robustness of connectivity assessments and ensure that current trends in connectivity modeling contribute to GI with their full potential, common denominators on which to ground planning and design strategies are required. Likewise, comparable, repeatable connectivity assessments will be needed to put results of these scientific tools into practice for multi-functional GI plans and implementation. In this paper, we discuss use and limitations of state-of-the-art connectivity methods in contributing to GI implementation.

Genetic Diversity and Demographic Connectivity of Atlantic Green Sea Turtles at Foraging Grounds in Northeastern Colombia, Caribbean Sea

The Atlantic green sea turtle Chelonia mydas is a migratory and endangered species with a network of nesting rookeries and foraging grounds in the Atlantic basin that needs elucidation. Foraging grounds are important areas for immature turtle’s feeding and growth after pelagic migrations. Aggregations of sea turtles at these grounds usually come from genetically distinct nesting rookeries; therefore, they are called mixed stocks. The northeastern coast of Colombia has extensive seagrass and macroalgae marine ecosystems that constitute foraging grounds, and perhaps long-term developmental habitats for a significant number of immature C. mydas. However, it is unknown which C. mydas nesting rookeries may be using these ecosystems for feeding and development. This study estimated the genetic diversity and genetic origin of C. mydas mixed stocks at two foraging grounds in northeastern Colombia (Santa Marta and La Guajira), and inferred their connections to nesting rookeries groups in the Atlantic basin using mitochondrial Control Region (mtCR) as a marker. A high genetic diversity, evidenced by the high nucleotide and haplotype diversities, was found in both studied mixed stocks and may be explained by different contributing nesting rookeries groups found with mixed stock analyses. At least three genetically distinct groups from different sides of the Atlantic Basin contributed juveniles to the mixed stocks in Colombia. Observed demographic connectivity can be explained by the confluence of two major, opposite directions ocean currents by the study area, the Caribbean Current (westward) and the Panama-Colombia Countercurrent (eastward). The high diversity of turtles at Colombia’s foraging grounds suggests the area is an important link in the network of habitats used by C. mydas to be considered in management and transnational conservation planning for the species recovery.