A novel holistic framework for genetic‐based captive‐breeding and reintroduction programs

Abstract

Research in reintroduction biology has provided a greater understanding of the often limited success of species reintroductions and highlighted the need for scientifically rigorous approaches in reintroduction programs. We examined the recent genetic-based captive-breeding and reintroduction literature to showcase the underuse of the genetic data gathered. We devised a framework that takes full advantage of the genetic data through assessment of the genetic makeup of populations before (past component of the framework), during (present component), and after (future component) captive-breeding and reintroduction events to understand their conservation potential and maximize their success. We empirically applied our framework to two small fishes: Yarra pygmy perch (Nannoperca obscura) and southern pygmy perch (Nannoperca australis). Each of these species has a locally adapted and geographically isolated lineage that is endemic to the highly threatened lower Murray-Darling Basin in Australia. These two populations were rescued during Australia's recent decade-long Millennium Drought, when their persistence became entirely dependent on captive-breeding and subsequent reintroduction efforts. Using historical demographic analyses, we found differences and similarities between the species in the genetic impacts of past natural and anthropogenic events that occurred in situ, such as European settlement (past component). Subsequently, successful maintenance of genetic diversity in captivity-despite skewed brooder contribution to offspring-was achieved through carefully managed genetic-based breeding (present component). Finally, genetic monitoring revealed the survival and recruitment of released captive-bred offspring in the wild (future component). Our holistic framework often requires no additional data collection to that typically gathered in genetic-based breeding programs, is applicable to a wide range of species, advances the genetic considerations of reintroduction programs, and is expected to improve with the use of next-generation sequencing technology.

Landscape genetics informs mesohabitat preference and conservation priorities for a surrogate indicator species in a highly fragmented river system

“…Many native MDB species have poor or moderate dispersal potential and a relatively high degree of habitat specialization. These characteristics, in combination with humandriven fragmentation and disturbance of the basin (Lintermans, 2007;Hammer et al, 2013), account for the high population structure and isolation typically detected in population genetic studies of MDB fishes (see, for example, Faulks et al, 2011;Brauer et al, 2013;Attard et al, 2016;Cole et al, 2016;Sasaki et al, 2016). Therefore, our microsatellite results support the proposal that G. marmoratus represents a valuable surrogate indicator species of how fragmentation might affect co-occurring low dispersal species in affected riverine ecosystems.…”

“…These findings are also consistent with coalescent-based and genome-wide analyses of a co-occurring poor dispersal species in the MDB, the southern pygmy perch Nannoperca australis. Here, isolation and basin-wide demographic declines observed for several populations are better explained by human-driven disturbances that post-date European settlement than by the historical effects of genetic drift (Attard et al, 2016;Brauer et al, 2016;Cole et al, 2016). Such analyses would probably prove useful to better delineate factors that have shaped the history of isolation of G. marmoratus populations.…”

“…Riverscape genetics of a poor dispersal fish J Lean et al action recently conducted with endangered fishes in the MDB is genetically informed captive breeding followed by reintroduction to the wild Attard et al, 2016). This was implemented for four endangered species in the lower Murray and was particularly successful with two species of pygmy perches.…”

“…This was implemented for four endangered species in the lower Murray and was particularly successful with two species of pygmy perches. Genetic diversity in pygmy perches was maintained after one generation of captive breeding, a few thousand offspring were reintroduced to the wild after some habitat recovery, and subsequent recapturing events demonstrated not only survival but also recruitment of captive-born individuals (Attard et al, 2016). However, the same program had very limited success in breeding G. marmoratus in captivity as a larger and territorial species.…”

Maximising evolutionary potential in functional proxies for extinct species: a conservation genetic perspective on de‐extinction

“…Genetic diversity may be further eroded by genetic drift in captivity if founder representation is not equalised and monitored regularly (e.g. Attard et al 2016;Hammerly et al 2016).…”