Global patterns of raptor distribution and protected areas optimal selection to reduce the extinction crises

Carlos Cruz,Giulia Santulli-Sanzo,Gerardo Ceballos

doi:10.1073/pnas.2018203118

Abstract

Globally, human-caused environmental impacts, such as habitat loss, have seriously impacted raptor species, with some 50% of species having decreasing populations. We analyzed global patterns of distribution of all 557 raptor species, focusing on richness, endemism, geographic range, conservation status, and population trends. Highest species diversity, endemism, species at risk, or restricted species were concentrated in different regions. Patterns of species distribution greatly differed between nocturnal and diurnal species. To test the efficiency of the global protected areas in conserving raptors, we simulated and compared global reserve systems created with strategies aiming at: 1) constraining the existing system into the final solution; and 2) minimizing the socioeconomic cost of reserve selection. We analyzed three targets of species distribution to be protected (10, 20, 30%). The first strategy was more efficient in meeting targets and less efficient in cost and compactness of reserves. Focusing on actions in the existing protected areas is fundamental to consolidate conservation, and politically and economically more viable than creating new reserves. However, creating new reserves is essential to protect more populations throughout the species' geographic range. Our findings provide a fundamental understanding of reserves to maintain raptor diversity and reduce the global population and species extinction crisis.

Highlights

Human-caused environmental impacts, such as habitat loss, have seriously impacted raptor species, with some 50% of species having decreasing populations
In Africa, West Africa, vulture populations have decreased by an average of 95% in rural areas over the last 30 y as the result of shooting, harassment, and poisoning through feeding on carcasses of livestock treated with diclofenac [23]
We present a global analysis of the distribution patterns of 557 of all raptor species in order to evaluate conservation priorities based on four parameters: 1) global distribution patterns of total, diurnal, and nocturnal species, species at risk, endemic species, and species with restricted ranges; 2) species population trends; 3) selection of areas that minimize conflict with human activities; and 4) effectiveness of the protected area network

Summary

Introduction

Human-caused environmental impacts, such as habitat loss, have seriously impacted raptor species, with some 50% of species having decreasing populations. Raptors are some of the most threatened vertebrate taxa, and in the last three decades many species have experienced severe population declines or faced extinction [7, 8] This threat is primarily the result of habitat loss and fragmentation, pollution, human–wildlife conflicts, and global climate alterations [5,6,7,8,9]. Our results provide insights into global strategies for conservation of different proportions of the geographic range of raptor species, minimizing socioeconomic conflict. These findings are fundamental to guide conservation actions that may help avert the massive current extinction crises

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Conclusion