Biology subjects

de Greef, E.

Publications and source records attributed to de Greef, E..

5 recordsLinked to original sources

bioRxiv2024

Urbanization is associated with reduced genetic diversity in marine fish populations

The economic and ecological benefits of living by the ocean have led many coastal settlements to grow into large densely populated cities. Large coastal cities have had considerable environmental effects on marine ecosystems through resource extraction, waste disposal, and use for transportation. Thus, it is important to understand the consequences of urbanization and human activities on evolutionary processes and biodiversity in marine fishes. Using published population genetic datasets for marine fishes amounting to 75,496 individuals sampled from 73 species at 1143 sample sites throughout the worlds oceans, we evaluated how human population density and a composite measure of cumulative human impacts affected genetic diversity and differentiation. We found that genetic diversity was significantly lower in marine fish populations associated with denser human populations regardless of species and locality. The effects of cumulative human impacts on genetic diversity were less prominent, perhaps due to this measure capturing more spatially varying processes. Urbanization in coastal regions has degraded marine biodiversity in a way that erodes adaptive potential for marine fish populations. This highlights the need to mitigate threats from human activities and focus efforts on sustainable urban planning and resource use to conserve marine biodiversity sustaining coastal fisheries and ecosystems.

evolutionary biology↗

bioRxiv2024

Unraveling the genetic legacy of commercial whaling in bowhead whales and narwhals

Commercial whaling decimated many whale populations over several centuries. Bowhead whales (Balaena mysticetus) and narwhal (Monodon monoceros) have similar habitat requirements and are often seen together in the Canadian Arctic. Although their ranges overlap extensively, bowhead whales experienced significantly greater whaling pressure than narwhals. The different harvest histories but similar habitat requirements of these two species provide an opportunity to examine the demographic and genetic consequences of commercial whaling. We whole-genome resequenced Canadian Arctic bowhead whales and narwhals to delineate population structure and reconstruct demographic history. Bowhead whale effective population size sharply declined contemporaneously with the intense commercial whaling period. Narwhals instead exhibited recent growth in effective population size, reflecting limited opportunistic commercial harvest. Although the genetic diversity of bowhead whales and narwhals was similar, bowhead whales had more genetic diversity prior to commercial whaling and will likely continue to experience significant genetic drift in the future. In contrast, narwhals appear to have had long-term low genetic diversity and may not be at imminent risk of the consequences of the erosion of genetic diversity. This work highlights the importance of considering population trajectories in addition to genetic diversity when assessing the genetics of populations for conservation and management purposes.

genomics↗

bioRxiv2023

Climate change introduces threatened killer whale populations and conservation challenges to the Arctic

The Arctic is the fastest-warming region on the planet, and sea ice loss has opened new habitat for sub-Arctic species such as the killer whale (Orcinus orca). As apex predators, killer whales can cause significant ecosystem-scale changes, however, we know very little about killer whales in the Arctic. Setting conservation priorities for killer whales and their Arctic prey species requires knowledge of their evolutionary history and demography. We found that there are two highly genetically distinct, non-interbreeding populations of killer whales using the eastern Canadian Arctic--one population is newly identified as globally distinct. The effective sizes of both populations recently declined, and both are vulnerable to inbreeding and reduced adaptive potential. Furthermore, we present evidence that human-caused mortalities, particularly ongoing harvest, pose an ongoing threat to these populations. The certainty of substantial environmental change in the Arctic complicates conservation and management significantly. Killer whales bring top-down pressure to Arctic food webs, however, they also merit conservation concern. The opening of the Arctic to killer whales exemplifies the magnitude of complex decisions surrounding local peoples, wildlife conservation, and resource management as the effects of climate change are realized.

genomics↗

bioRxiv2023

Migration distance and mating system are not associated with genetic diversity and differentiation among bats (Chiroptera)

Genetic variation is critical for evolutionary responses to environmental change. Links between genetic variation and behavioural or life history traits may reveal how varied strategies influence evolutionary trends in speciation and adaptation. Traits associated with movement typically correlate with population genetic structure and could help predict populations vulnerability to geographic processes such as habitat fragmentation and disease spread. With their wide diversity in behaviours and ecologies, bats provide a useful testing ground for hypotheses about population structure related to species-specific movement patterns. We used a global sample of microsatellite data (n=233 sites from 17 bat species) associated with published studies to examine potential links between genetic variation and migration and mating strategies. The genetic measures we tested were population-specific differentiation, gene diversity, and allelic richness. Using Bayesian models that accounted for phylogenetic distances among species, we identified no correlations between migration or mating strategy and genetic variation. Our results do not support long-standing hypotheses about dispersal-mediated genetic structure, and contrast with prior studies on bat genetic diversity and differentiation. We discuss the need for continued research into the complex association of ecological, biogeographical, and behavioural factors that facilitate gene flow among populations, especially in species with diverse movement patterns.

zoology↗

bioRxiv2022

Genomic architecture of migration timing in a long-distance migratory songbird

The impact of climate change on spring phenology poses risks to migratory birds, as migration timing is controlled predominantly by endogenous mechanisms. Despite numerous studies on internal cues controlling migration, the underlying genetic basis of migration timing remains largely unknown. We investigated the genetic architecture of migration timing in a long-distance migratory songbird (purple martin, Progne subis subis) by integrating genomic data with an extensive dataset of direct migratory tracks. Our findings show migration has a predictable genetic basis in martins and maps to a region on chromosome 1. This region contains genes that could facilitate nocturnal flights and act as epigenetic modifiers. Additionally, we found that genomic variance explained a higher proportion of historic than recent environmental spring phenology data, which may suggest a reduction in the adaptive potential of migratory behavior in contemporary populations. Overall, these results advance our understanding of the genomic underpinnings of migration timing and could provide context for conservation action.

genomics↗