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

Camilo A Calderón-Acevedo,J Angel Soto-Centeno,Armando Rodríguez-Durán

doi:10.1038/s41598-021-88616-7

Abstract

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.

Highlights

Urbanization and natural disasters can disrupt landscape connectivity, effectively isolating populations and increasing the risk of local extirpation in island systems
When land use alone was included as a resistance layer, i.e., differential permeability in the landscape depending on the type of land use, the model produced an even connectivity gradient across the island (Fig. 2A)
The current population trend of S. rufum is u nknown[35], our results suggest that land use, natural disasters, and the availability of suitable habitat remaining play a role in maintaining the connectivity across the landscape for this bat

Summary

Introduction

Urbanization and natural disasters can disrupt landscape connectivity, effectively isolating populations and increasing the risk of local extirpation in island systems. The Caribbean island of Puerto Rico, itself a small archipelago of some 140 small islands and cays, contains seven different types of forest h abitats[15,16] These forests are subject to various levels of anthropogenic and natural pressures across the island derived from urban development concentrated in the northeast and south-central areas[17], and agricultural development located primarily in the west and southwest. The protected and rustic areas form corridors that span from east to west and connect all forest types and protected areas in the main island of Puerto Rico. El Yunque National Forest, itself the largest protected area of the island, and the nearby Carite State Forest (Fig. 1A and B, respectively) contain subtropical wet and rain forests and lower montane wet and rain forests Notwithstanding, these large protected areas are under anthropogenic pressure and are affected by u rbanization[17]. The negative effects of hurricanes on S. rufum in Puerto Rico could be exacerbated by the poor continuity of forest patches connecting local demes between the east and west of the island

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Results

Conclusion