Population genetic structure of raccoons as a consequence of multiple introductions and range expansion in the Boso Peninsula, Japan

Miki Hirose,Eiji Inoue,Masami Hasegawa,Kazuya Yoshida

doi:10.1038/s41598-021-98029-1

Abstract

The raccoon (Procyon lotor) is an invasive carnivore that invaded various areas of the world. Although controlling feral raccoon populations is important to reduce serious threats to local ecosystems, raccoons are not under rigid population control in Europe and Japan. We examined the D-loop and nuclear microsatellite regions to identify spatially explicit and feasible management units for effective population control and further range expansion retardation. Through the identification of five mitochondrial DNA haplotypes and three nuclear genetic groups, we identified at least three independent introductions, range expansion, and subsequent genetic admixture in the Boso Peninsula. The management unit considered that two were appropriate because two populations have already genetic exchange. Furthermore, when taking management, we think that it is important to monitor DNA at the same time as capture measures for feasible management. This makes it possible to determine whether there is a invasion that has a significant impact on population growth from out of the unit, and enables adaptive management.

Highlights

Controlling invasive species is important for reducing threats to biodiversity and natural resources on a global scale[1], because introduced species may disrupt local ecosystems and eliminate native species through predation and herbivory competition, pathogen transmission, or h ybridization[2]
The newly released or escaped captive raccoons or animals dispersed from adjacent areas should account for the origin of raccoon populations in Boso Peninsula
Boso Peninsula is almost isolated from the adjacent prefecture by the sea and the large rivers of Tonegawa River and Edogawa River (Fig. 1); either human-induced re-introduction from other areas or released or escaped captive pets should be the primary sources of feral raccoons in Boso Peninsula

Summary

Introduction

Controlling invasive species is important for reducing threats to biodiversity and natural resources on a global scale[1], because introduced species may disrupt local ecosystems and eliminate native species through predation and herbivory competition, pathogen transmission, or h ybridization[2]. When the target species have gender differences in dispersion distance, only males are distributed in the foremost part of the distribution expansion area, and a low-density region “lag-phase” is formed, where the Allee-effect[13] retards population growth. It is difficult to achieve eradication, maintaining lag-phase by applying capture pressure is possible We think that this lag-phase management can effectively prevent the expansion of the distribution area. It is important to understand the current genetic structure and set an appropriate management unit. This enables adaptive management by monitoring whether it occurs to exchange with other regions and whether countermeasures are successful. If we focus on a geographically limited area, we might be able to examine the details of range expansion in association with landscape and genetic structures within a particular region

Methods

Results

Conclusion