Population genomics of Sitka black-tailed deer supports invasive species management and ecological restoration on islands

Brock T Burgess,Michael A Russello,Robyn L Irvine

doi:10.1038/s42003-022-03159-5

Brock T Burgess, Michael A Russello + Show 1 more

Open Access

https://doi.org/10.1038/s42003-022-03159-5

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Abstract

Invasive mammals represent a critical threat to island biodiversity; eradications can result in ecological restoration yet may fail in the absence of key population parameters. Over-browsing by invasive Sitka black-tailed deer (Odocoileus hemionus sitkensis) is causing severe ecological and cultural impacts across the Haida Gwaii archipelago (Canada). Previous eradication attempts demonstrate forest regeneration upon deer removal, but reinvasion reverses conservation gains. Here we use restriction-site associated DNA sequencing (12,947 SNPs) to investigate connectivity and gene flow of invasive deer (n = 181) across 15 islands, revealing little structure throughout Haida Gwaii and identifying the large, central island of Moresby (>2600 km2) as the greatest source of migrants. As a result, the archipelago itself should be considered the primary eradication unit, with the exception of geographically isolated islands like SGang Gwaay. Thus, limiting eradications to isolated islands combined with controlled culling and enhanced biosecurity may be the most effective strategies for achieving ecological restoration goals.

Highlights

Invasive mammals represent a critical threat to island biodiversity; eradications can result in ecological restoration yet may fail in the absence of key population parameters
There is a need for quantitative tools to assist managers in the decision-making process before, during, and after management operations to increase chances of successful ecological restoration, while minimizing the costs associated with eradication failure
Sequencing of four restriction-site associated DNA sequencing (RADseq) libraries yielded 1,013,204,998 total forward and reverse DNA sequence reads from Sitka black-tailed deer harvested across 15 islands in Haida Gwaii (Fig. 1 and Supplementary Table 1)

Summary

Introduction

Invasive mammals represent a critical threat to island biodiversity; eradications can result in ecological restoration yet may fail in the absence of key population parameters. Over-browsing by invasive Sitka black-tailed deer (Odocoileus hemionus sitkensis) is causing severe ecological and cultural impacts across the Haida Gwaii archipelago (Canada). Efforts to remove such species are costly and subject to failure; for example, mammal eradication attempts on islands throughout the world have resulted in a ~15% failure rate[4]. Eradication failures, those resulting from rapid recolonization, are often due to knowledge gaps of key population parameters, including population connectivity and dispersal capacity[5]. Columbia (Canada), in the late 19th century and have become a widespread invasive species in the 50–80 generations since[15]

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