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Connectivity is crucial for species conservation, but most assessments define connectivity solely in terms of protected or natural areas and land covers without regard for the underlying thermal environment. As climate change accelerates, it is becoming increasingly important to not only assess land use and land cover changes (LULCC) but also how surface temperatures are evolving and creating more fragmented thermal refuges over time. This research investigates how the surface thermal environment has changed over time in Phoenix, Arizona, USA, a desert city in the southwestern United States, and how the spatial patterns of cooler refuges within the heat landscape, or “heatscape,” may be affecting wildlife habitat availability alongside LULCC. We quantify the structural and functional connectivity of thermal refuges using a suite of connectivity metrics from landscape ecology to demonstrate how the spatial distribution and configuration of these critical areas has changed over the last 35 years and what the implications are for the many wildlife species living in this desert environment. Results show that thermal refuge patches have been shrinking and becoming more fragmented over the past 35 years, with connectivity also declining over the same period. A key inflection point was identified in 2000, when the probability that cooler refuges patches were connected dropped to nearly zero, and it has remained at that low level ever since. These shifts in connectivity are tightly coupled with LULCC in the study area, particularly the loss of irrigated agriculture as it has been replaced by residential and other developed land uses over time. Decreasing water security in the region also threatens to reduce the availability of cooler patches and, simultaneously, the connectivity of those refuges. Introducing cooler patches through engineered materials or artificial shade may help offset some of the losses from irrigated lands. The findings offer a perspective for conservation research with implications for advancing a more formal thermal landscape ecology for understanding and improving the relationship between spatial thermal patterns and ecological processes.
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Optimization Model and Solution Algorithm for the Design of Connected and Compact Nature Reserves
Ecosystem conservation is fundamental to guarantee the survival of endangered species and to preserve other ecological functions important for human systems (e.g., water). Planning land conservation increasingly requires a landscape approach to mitigate the negative impacts of spatial threats such as urbanization, agricultural development, and climate change. In this context, landscape connectivity and compactness are vital characteristics for the effective functionality of conservation areas. Connectivity allows species to travel across landscapes, facilitating the flow of genes across populations from different protected areas. Compactness measures the spatial dispersion of protected sites, which can be used to mitigate risk factors associated with species leaving and reentering the reserve. This research describes an optimization model for the design of conservation areas, while inducing connectivity and compactness. We use the Reocks index, a metric of compactness that maximizes the ratio of area of the selected patches to the area of their smallest circumscribing circle. Our model includes budget and minimum protected area constraints to reflect realistic financial and ecological requirements. The initial nonlinear model is reformulated into a mixed-integer linear program, which is solved using an adaptation of the Newtons method for problems with integer variables. We characterize an optimal solution and derive cuts to improve the model performance. We illustrate our results using real life landscapes with irregular patches.
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- Award ID(s):
- 2308687
- PAR ID:
- 10538671
- Editor(s):
- Babski-Reeves, K; Eksioglu, B; Hampton, D
- Publisher / Repository:
- ProQuest
- Date Published:
- Format(s):
- Medium: X
- Location:
- https://www.proquest.com/docview/2878499128/abstract/451DE6F3AF7B4764PQ/1?accountid=10920&sourcetype=Scholarly%20Journals
- Sponsoring Org:
- National Science Foundation
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Balancing the competing, and often conflicting, needs of people and wildlife in shared landscapes is a major challenge for conservation science and policy worldwide. Connectivity is critical for wildlife persistence, but dispersing animals may come into conflict with people, leading to severe costs for humans and animals and impeding connectivity. Thus, conflict mitigation and connectivity present an apparent dilemma for conservation. We present a framework to address this dilemma and disentangle the effects of barriers to animal movement and conflict-induced mortality of dispersers on connectivity. We extend random-walk theory to map the connectivity–conflict interface, or areas where frequent animal movement may lead to conflict and conflict in turn impedes connectivity. We illustrate this framework with the endangered Asian elephantElephas maximus, a species that frequently disperses out of protected areas and comes into conflict with humans. We mapped expected movement across a human-dominated landscape over the short- and long-term, accounting for conflict mortality. Natural and conflict-induced mortality together reduced expected movement and connectivity among populations. Based on model validation, our conflict predictions that explicitly captured animal movement better explained observed conflict than a model that considered distribution alone. Our work highlights the interaction between connectivity and conflict and enables identification of location-specific conflict mitigation strategies that minimize losses to people, while ensuring critical wildlife movement between habitats. By predicting where animal movement and humans collide, we provide a basis to plan for broad-scale conservation and the mutual well-being of wildlife and people in shared landscapes.more » « less
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Abstract Climate change and land use change are two main drivers of global biodiversity decline, decreasing the genetic diversity that populations harbour and altering patterns of local adaptation. Landscape genomics allows measuring the effect of these anthropogenic disturbances on the adaptation of populations. However, both factors have rarely been considered simultaneously. Based on a set of 3660 SNPs from which 130 were identified as outliers by a genome–environment association analysis (LFMM), we modelled the spatial turnover of allele frequencies in 19 localities ofPinus leiophyllaacross the Avocado Belt in Michoacán state, Mexico. Then, we evaluated the effect of climate change and land use change scenarios, in addition to evaluating assisted gene flow strategies and connectivity metrics across the landscape to identify priority conservation areas for the species. We found that localities in the centre‐east of the Avocado Belt would be more vulnerable to climate change, while localities in the western area are more threatened by land conversion to avocado orchards. Assisted gene flow actions could aid in mitigating both threats. Connectivity patterns among forest patches will also be modified by future habitat loss, with central and eastern parts of the Avocado Belt maintaining the highest connectivity. These results suggest that areas with the highest priority for conservation are in the eastern part of the Avocado Belt, including the Monarch Butterfly Biosphere Reserve. This work is useful as a framework that incorporates distinct layers of information to provide a more robust representation of the response of tree populations to anthropogenic disturbances.more » « less
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