DOI: 10.5061/dryad.rv15dv46c
title: Data from: The impact of anthropogenic disturbances on the genetic diversity of terrestrial species: a global meta-analysis

description: Duplicate of 10.5061/dryad.6hdr7sqxq Human activities are primarily
 responsible for habitat loss and changes in natural environments around
 the world. It has been suggested that populations inhabiting
 human-modified landscapes experience reduced gene flow, inbreeding
 depression, and loss of alleles due to genetic drift. However, the
 empirical evidence shows contrasting effects of anthropogenic disturbances
 on the genetic diversity of species. We performed a meta-analysis of 61
 studies that compared the genetic diversity of plant and/or animal
 populations in disturbed and more preserved areas (316 paired comparisons)
 to investigate the genetic responses to different disturbance types. There
 is a negative effect (effect size: -0.45; 95% CI: -0.61, -0.29) of
 disturbances on genetic diversity, in which the most detrimental effects
 are caused by the loss of connectivity and forest cover. The
 methodological approach can explain part of the heterogeneity among the
 genetic responses detected by primary studies: (i) studies using the
 number of effective alleles did not detect genetic erosion, while all
 other indices, revealed negative responses to disturbances; and (ii) only
 studies performed with transferred or a combination of transferred and
 specific microsatellites detected negative responses. The effects on
 animal populations are more detrimental than in plant populations. Only
 plant species with shrub life form, self-incompatible reproductive
 systems, and biotic pollination and seed dispersal, showed negative
 responses to disturbances. Despite all heterogeneity among studies, there
 is an overall negative effect of disturbances on the genetic diversity,
 which indicates that remaining populations inhabiting human-modified
 landscapes have reduced evolutionary potential and are prone to local
 extinction.
description: We searched for studies that evaluated the effects of
 anthropogenic disturbances on plant and animal genetic diversity published
 before February 07<sup>th</sup>, 2019. The search was
 performed in the Scopus database using the following term sequences:
 [("Genetic diversity") AND (Microsatellite OR SSR) AND
 ("fragmented habitat" OR "habitat fragmentation" OR
 deforest* OR logging OR "habitat disturbance" OR "disturbed
 habitat" OR "habitat loss")]. These terms were searched for
 in the title, abstract, and keyword sections of the manuscripts, except
 for the sequence of terms related to the genetic marker, which were
 searched for in the entire manuscript. Initially, we
 identified 1,263 manuscripts that were screened based on the following
 additive criteria (Figure S1, Supporting information 1):
 <b>I.</b> studies that explicitly evaluated the
 effects of anthropogenic disturbances on the genetic diversity of
 terrestrial plants and/or animals. We considered six genetic
 descriptive parameters as measures of genetic diversity:
 observed and expected heterozygosity (H<sub>O</sub> and
 H<sub>E</sub>), allelic richness (Ar), mean number of alleles
 (A), mean number of effective alleles (Ae), and mean number of private
 alleles (Ap); <b>II.</b> studies that used microsatellite
 markers; <b>III.</b> studies that evaluated genetic diversity
 along a gradient of anthropogenic disturbances or compared it between
 relatively preserved (control) and disturbed (treatment) areas in the same
 geographical region. We considered four categories of local-scale
 disturbance – (1) habitat quality, (2) patch size, (3) edge effects, and
 (4) land use intensification – and three categories of landscape-scale
 disturbance – (1) landscape quality, (2) connectivity, and (3) forest
 cover; I<b>V.</b> studies that provided values of sample size
 and genetic parameters (mean estimate and error measure for each
 treatment, or linear regression coefficients for gradient studies) for all
 evaluated populations; <b>V</b>. studies with replication of
 treatments and control groups, and <b>VI</b>. studies
 published in the English language. Details about the criteria for studies
 inclusion are presented in the Supplementary Information. The reviews and
 meta-analyses identified in the initial search were used as a source of
 additional papers for our database, to which 4 additional manuscripts were
 included. This screening procedure resulted in 61
 studies and 316 paired comparisons (mean ± SD = 5.2 ± 3.1 comparisons per
 study). For each paired comparison we extracted the sample size, mean
 value of genetic parameter and standard deviation per treatment. In case
 of gradient studies, we extracted the sample size and the linear
 regression coefficient. Additionally, we extracted information about each
 study methodology such as the genetic parameter, type of microsatellite
 marker used, number of loci analyzed, investigated taxa (amphibians,
 birds, insects, mammals, reptiles, and plants), and life history traits of
 plant species . Whenever information was not available in the manuscript,
 we searched the literature to obtain it.