Endemic species predation by the introduced smooth-billed ani in Galápagos

Funder: International Community FoundationFunder: Christ's College, University of Cambridge; doi: http://dx.doi.org/10.13039/501100000590Abstract: The introduced smooth-billed ani Crotophaga ani has become widespread across the Galápagos archipelago in the past half-century. It is known to predate upon a range of native and endemic species, and is a potential vector for the spread of invasive plants and parasites. Here we report previously undocumented examples of smooth-billed ani predation in Galápagos, including that of an endemic racer snake and a scorpion. We highlight the possibility of smooth-billed anis having a serious impact on the endemic Galápagos carpenter bee, a major pollinator, as well as native and endemic Lepidopterans and other invertebrates. In addition, we report smooth-billed ani predation of other introduced species and note the importance of further research on the wide-scale impacts of smooth-billed anis in Galápagos and their role within the archipelago’s ecological networks

Genomic Adaptations to Salinity Resist Gene Flow in the Evolution of Floridian Watersnakes

The migration-selection balance often governs the evolution of lineages, and speciation with gene flow is now considered common across the tree of life. Ecological speciation is a process that can facilitate divergence despite gene flow due to strong selective pressures caused by ecological differences; however, the exact traits under selection are often unknown. The transition from freshwater to saltwater habitats provides strong selection targeting traits with osmoregulatory function. Several lineages of North American watersnakes (Nerodia spp.) are known to occur in saltwater habitat and represent a useful system for studying speciation by providing an opportunity to investigate gene flow and evaluate how species boundaries are maintained or degraded. We use double digest restriction-site associated DNA sequencing to characterize the migration-selection balance and test for evidence of ecological divergence within the Nerodia fasciata-clarkii complex in Florida. We find evidence of high intraspecific gene flow with a pattern of isolation-by-distance underlying subspecific lineages. However, we identify genetic structure indicative of reduced gene flow between inland and coastal lineages suggesting divergence due to isolation-by-environment. This pattern is consistent with observed environmental differences where the amount of admixture decreases with increased salinity. Furthermore, we identify significantly enriched terms related to osmoregulatory function among a set of candidate loci, including several genes that have been previously implicated in adaptation to salinity stress. Collectively, our results demonstrate that ecological differences, likely driven by salinity, cause strong divergent selection which promotes divergence in the N. fasciata-clarkii complex despite significant gene flow

Filling in the Gaps: Clonophis kirtlandii in Illinois

Kirtland’s snake (Clonophis kirtlandii) is a small, enigmatic, and fossorial snake species endemic to the prairie peninsula region. In 2017, this species was reviewed by the USFWS for federal listing, but protection was deemed unwarranted due to insufficient knowledge regarding its natural history, distribution, population size, and threats. However, Kirtland’s snake remains listed as threatened, endangered, or critically imperiled in all eight states – Illinois, Indiana, Kentucky, Michigan, Missouri, Ohio, Pennsylvania, and Tennessee – in which it occurs. A more credible assessment of the current and future status of Kirtland’s snake thus requires new and more rigorous information. The aim of this study is to (1) identify extant populations of Kirtland’s snake in Illinois, (2) expand our knowledge of habitat preferences, (3) investigate floral and faunal community associations, and (4) describe historic and current zoogeographic relationships. To accomplish these objectives, we will actively survey historic and potential localities for presence data, assess the habitat at extant sites, collect and identify crayfish and annelid specimens, monitor extant populations, and utilize niche modeling at various scales to delineate historic, contemporary, and future aspects of its distribution, evolution, and fate. Recent findings include a number of newly discovered populations that suggest Kirtland’s snake may be more widespread in Illinois than previously thought. However, little is understood of the governing principles behind the species’ sporadic persistence in the state. This investigation will provide key insights into the distribution and associations of Kirtland’s snake, thus providing guidance for future conservation management.Ope

Endemic species predation by the introduced smooth-billed ani in Galápagos

Funder: International Community FoundationFunder: Christ's College, University of Cambridge; doi: http://dx.doi.org/10.13039/501100000590Abstract: The introduced smooth-billed ani Crotophaga ani has become widespread across the Galápagos archipelago in the past half-century. It is known to predate upon a range of native and endemic species, and is a potential vector for the spread of invasive plants and parasites. Here we report previously undocumented examples of smooth-billed ani predation in Galápagos, including that of an endemic racer snake and a scorpion. We highlight the possibility of smooth-billed anis having a serious impact on the endemic Galápagos carpenter bee, a major pollinator, as well as native and endemic Lepidopterans and other invertebrates. In addition, we report smooth-billed ani predation of other introduced species and note the importance of further research on the wide-scale impacts of smooth-billed anis in Galápagos and their role within the archipelago’s ecological networks