DOI: 10.5061/dryad.fxpnvx0vm
title: Can antioxidant responses be induced by habitat fragmentation process?

description: Animal populations are increasingly forced to live in small residual
 natural or semi-natural areas due to habitat loss and fragmentation. Here,
 the viability of populations is often compromised by intrinsic threat
 factors typical of small and isolated populations, such as inbreeding
 depression, genetic drift, and environmental and demographic
 stochasticity. Under these circumstances, organisms may have low fitness
 due to inadequate physiological responses needed to face environmental
 challenges. However, few studies have investigated the relationship
 between habitat fragmentation and stress defences. In this study, we aimed
 to test whether an increase in the level of individual inbreeding produced
 an increase in the antioxidant system response. To this purpose, we
 genotyped 151 individuals of Fire Salamander Salamandra salamandra
 (Amphibia: Urodela) within 5 sampling populations, located in forest
 landscapes with different degree of fragmentation in northern Italy. For
 113 individuals we also measured the glutathione-S-transferase (GST) and
 catalase (CAT) enzyme activity. Results showed a significant increase in
 individual GST activity for increasing levels of inbreeding, whereas no
 relationship was found for CAT. We also measured acetylcholinesterase to
 test the possible confounding effects of pesticides that might have
 occurred in fragmented landscapes with forests interspersed with
 agricultural areas. However, no difference in this enzyme activity was
 found among sampling populations. We argue that high levels of GST
 activity may be symptomatic of oxidative stress derived from inbreeding.
 An increased frequency of homozygous deleterious alleles due to inbreeding
 may cause homeostatic alterations and trigger the expression of GST for
 protection against hydrogen peroxide reactive oxygen species. We suggest
 using GST as a biomarker for environmental stressors with great caution
 and not to underestimate that the sources of stress deriving from habitat
 fragmentation could lead to an unbalance in the oxidative status, possibly
 increasing population susceptibility to infectious diseases and,
 potentially, spillover events and zoonoses.
description: The dataset is composed of genetic and enzymatic data of Fire
 Salamander larvae and water parameters of sampled pools. Biological
 samples have been collected from larvae at multiple sampling sites in
 Northern Italy, which were arranged along an habitat fragmentation
 gradient. Biological samples for genetic analysis were processed according
 to methods in Pisa et al. (2015). The individual inbreeding coefficient
 (F) was estimated using genotype data obtained from the 16
 species-specific microsatellites of Pisa et al. (2015) through the
 adegenet package in R. Biological samples for enzyme analysis were
 suspended and homogenised, the crude extract was then centrifuged and the
 supernatant was used to measure the enzyme activity of GST, CAT and AChE.
 Water parameters include water temperature, O2 saturation, pH,
 conductivity, total nitrogen and total phosphorus. The
 first sheet (Enzymatic, Gentic & Water data) includes enzyme
 activities and Inbreeding coefficient averaged at the sampling location
 scale.  The second sheet (Individual Enzymatic data)
 includes enzyme activities at the individual scale.
description: The data file is in .xlsx format, which can be opened in
 Microsoft Excel or OpenOffice.