The Promise of Genetics and Genomics for Improving Invasive Mammal Management on Islands

Abstract

Invasive species are major contributors to global biodiversity decline. Invasive mammalian species (IMS), in particular, have profound negative effects in island systems that contain disproportionally high levels of species richness and endemism. The eradication and control of IMS have become important conservation tools for managing species invasions on islands, yet these management operations are often subject to failure due to knowledge gaps surrounding species- and system-specific characteristics, including invasion pathways and contemporary migration patterns. Here, we synthesize the literature on ways in which genetic and genomic tools have effectively informed IMS management on islands, specifically associated with the development and modification of biosecurity protocols, and the design and implementation of eradication and control programs. In spite of their demonstrated utility, we then explore the challenges that are preventing genetics and genomics from being implemented more frequently in IMS management operations from both academic and non-academic perspectives, and suggest possible solutions for breaking down these barriers. Finally, we discuss the potential application of genome editing to the future management of invasive species on islands, including the current state of the field and why islands may be effective targets for this emerging technology.

A genotyping‐in‐thousands by sequencing panel to inform invasive deer management using noninvasive fecal and hair samples

“…eDNA has been demonstrated as an effective noninvasive approach for invasive species research; however, such approaches are largely limited to presence‐absence detection (Beng & Corlett, 2020 ). Often, invasive species management can benefit from population‐level information, especially when planning eradications or culls (Browett et al, 2020 ; Burgess et al, 2021 ). For example, estimating population densities before a cull can help to inform stopping rules when target densities are reached, preventing excess resource investment (Ramsey et al, 2011 ).…”

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

“…As a result, management interventions such as invasive mammal eradication or control have become important strategies for mitigating biodiversity losses 1 , 2 . While proven to be effective when implemented successfully, eradications are often subject to failure due to the complex nature of species invasions; chances of success can be greatly improved with a priori knowledge of their invasion history, including population connectivity, contemporary movement patterns, and dispersal capacity 7 . Knowledge of these processes can further inform the development of biosecurity plans to maintain conservation gains from eradication or control programs over time.…”

“…Genetic and genomic tools have a proven history and promising future for informing invasive mammal management 6 , 7 . An early application involved population genetic analysis of invasive Norway rats ( Rattus norvegicus ) across 18 islands representing five archipelagos off the coast of France, where microsatellite genotypic data were used to determine eradication units (i.e., islands with sufficient gene flow to be considered single populations) and highlight the importance of conducting pre-eradication genetic surveys to minimize eradication failure 8 .…”

“…Since then, using genetic data for defining eradication units has become an effective strategy for invasive species management on islands, evidenced by its many applications and recommendations 5 , 9 , 10 . Genetic data can also be used to infer invasion pathways, including the source(s) of invasion, extent and direction of migration, and the dispersal capacity of a particular species 7 , 11 . Moreover, genotyping individuals before and after an eradication can better inform management outcomes by identifying the source of reinvasion and guiding subsequent planning 12 – 14 .…”

Genomic data is missing for many highly invasive species, restricting our preparedness for escalating incursion rates

“…‘invasion genetics’) for over 55 years 26 . This has resulted in broad understanding of the evolutionary processes associated with invasion, such as the general effects of bottlenecks and genetic drift on invasion success and the specific adaptive responses of some invasive species 27 . However, much invasive biology research still suffers from a lack of information around complex processes operating at the genomic level 28 , 29 .…”