No consistent effects of humans on animal genetic diversity worldwide

Abstract

Human impacts on genetic diversity are poorly understood yet critical to biodiversity conservation. We used 175 247 COI sequences collected between 1980 and 2016 to assess the global effects of land use and human density on the intraspecific genetic diversity of 17 082 species of birds, fishes, insects and mammals. Human impacts on mtDNA diversity were taxon and scale‐dependent, and were generally weak or non‐significant. Spatial analyses identified weak latitudinal diversity gradients as well as negative effects of human density on insect diversity, and negative effects of intensive land use on fish diversity. The observed effects were predominantly associated with species turnover. Time series analyses found nearly an equal number of positive and negative temporal trends in diversity, resulting in no net monotonic trend in diversity over this time period. Our analyses reveal critical data and theory gaps and call for increased efforts to monitor global genetic diversity.

Latitudinal biodiversity gradients at three levels: Linking species richness, population richness and genetic diversity

“…Despite this, Schluter and Pennell () demonstrated that mammalian and amphibian mitochondrial genetic diversity, equivalent to GenPerSpp here, has a slightly negative slope with latitude. Another study found some evidence for scale‐ and taxa‐dependent latitudinal gradients in genetic diversity (Millette et al, ). These results are mostly consistent with the expectations from a historical perspective, wherein species at low latitudes have experienced more time for genetic diversity to accumulate, but some nuances appear to blur gradient patterns.…”

“…The predictions for latitudinal genetic diversity patterns are more difficult to untangle due to the combined effects of history and current population size/distribution, and perhaps even the limited range/variability of genetic diversity levels (see Leffler et al, 2012 (Schluter, 2016), to have experienced fewer genetic bottlenecks, to have larger range sizes than tropical species (Stevens, 1989) (Cincotta, Wisnewski, & Engelman, 2000;Ellis & Ramankutty, 2008;Gibbs et al, 2010;Matthews, 1983). While the broad-scale impacts of humans on species genetic diversity are unclear (Millette et al, 2019), they could blur latitudinal patterns if human activities causing habitat loss reduce genetic diversity in regions where high levels of genetic diversity might be otherwise expected (see Ascensão et al, 2016;Cardillo et al, 2004;Cincotta et al, 2000). Collectively, a number of factors operating differently along the latitudinal gradient appear to have varying consequences for genetic diversity both among and within species.…”

“…Complicating expectations even further, anthropogenic impacts are highest at intermediate latitudes where most land conversion for agriculture and human population density exist (Cincotta, Wisnewski, & Engelman, ; Ellis & Ramankutty, ; Gibbs et al, ; Matthews, ). While the broad‐scale impacts of humans on species genetic diversity are unclear (Millette et al, ), they could blur latitudinal patterns if human activities causing habitat loss reduce genetic diversity in regions where high levels of genetic diversity might be otherwise expected (see Ascensão et al, ; Cardillo et al, ; Cincotta et al, ). Collectively, a number of factors operating differently along the latitudinal gradient appear to have varying consequences for genetic diversity both among and within species.…”

Building a global genomics observatory: Using GEOME (the Genomic Observatories Metadatabase) to expedite and improve deposition and retrieval of genetic data and metadata for biodiversity research

“…Likewise, repositories of species occurrence data such as GBIF have been transformational for ecological studies. With the exponential increase in genomic data from free‐living populations and species, molecular ecologists can now pursue expansive research programmes to yield deeper insights into how and why alleles, species, communities, and ecosystems are arrayed in space and time (Crandall, et al., 2019a; Crandall, et al., 2019b; Gratton et al., 2017; Manel et al., 2020; Millette et al., 2020; Miraldo et al., 2016; Salces‐Castellano et al., 2020; Smith et al., 2014) and toward the conservation of biodiversity (e.g., supporting the Group on Earth Observations Biodiversity Observation Networks; geobon.org/). These ambitious enterprises, however, necessitate that the metadata providing ecological context remain linked to DNA sequences.…”

“…Sample provenance, indigenous names, and value of the samples to indigenous communities can already be accommodated using existing metadata fields within GEOME. For example, in using existing and standard metadata fields to incorporate indigenous provenance and value, the New Zealand (Crandall, et al, 2019a;Crandall, et al, 2019b;Gratton et al, 2017;Manel et al, 2020;Millette et al, 2020;Miraldo et al, 2016;Salces-Castellano et al, 2020;Smith et al, 2014) and toward the conservation of biodiversity (e.g., supporting the Group on Earth Observations Biodiversity Observation Networks;…”