DOI: 10.5061/dryad.b2rbnzs9r
title: Context-dependent dispersal determines relatedness and genetic structure in a patchy amphibian population

description: Dispersal is a central process in ecology and evolution with far reaching
 consequences for the dynamics and genetics of spatially structured
 populations (SSPs). Individuals can adjust their decisions to disperse
 according to local fitness prospects, resulting in context-dependent
 dispersal. By determining dispersal rate, distance, and direction, these
 individual-level decisions further modulate the demography, relatedness,
 and genetic structure of SSPs. Here, we examined how context-dependent
 dispersal influences the dynamics and genetics of a Great Crested Newt
 (Triturus cristatus) SSP. We collected capture-recapture data of 5564
 individuals and genetic data of 950 individuals across a SSP in northern
 Germany. We added genetic data from six sites outside this SSP to assess
 genetic structure and gene flow at a regional level. Dispersal rates
 within the SSP were high but dispersal distances were short. Dispersal was
 context-dependent: individuals preferentially immigrated into high-quality
 ponds where breeding probabilities were higher. The studied SSP behaved
 like a patchy population, where subpopulations at each pond were
 demographically interdependent. High context-dependent dispersal led to
 weak but significant spatial genetic structure and relatedness within the
 SSP. At the regional level, a strong hierarchical genetic structure with
 very few first-generation migrants as well as low effective dispersal
 rates suggest the presence of independent demographic units. Overall, our
 study highlights the importance of habitat quality for driving
 context-dependent dispersal and therefore demography and genetic structure
 in SSPs. Limited capacity for long-distance dispersal seems to increase
 genetic structure within a population and leads to demographic isolation
 in anthropogenic landscapes.
description: Demographic Data (CMR and Presence/Absence
 Data): We surveyed 33 water bodies using
 mark-recapture methods for the presence, demography and reproduction of
 crested newts between 2012 and 2014. Newts were captured during two
 capture sessions (<i>cs</i>) per year, one early (April/May)
 and one late (June/July) in the breeding season. Every capture session
 thereby consisted of three consecutive capture events in intervals of two
 days. Within the context of a presence/absence analysis, all sites were
 surveyed for one more day in late July/early August in order to detect
 larvae. If a pond dried out and was therefore not surveyed during a
 capture session, such an event was treated as a missing
 observation. Newts were captured using Ortmann’s funnel
 traps which were evenly distributed along the shoreline of a pond. The
 number of traps deployed per capture event varied according to pond
 perimeter (one trap per 10m shoreline), ranging from one to 27 traps. For
 individual recognition of newts during the CMR study, we used photographs
 of the ventral side of an individual which provides a natural marking in
 form of a highly variable but individually unique and stable color pattern
 through the time. Recaptured individuals were identified automatically by
 the software AmphIdent. Microsatellite Genotypes: Tissue samples were taken from seven sampling sites by puncturing the tails of captured great crested newts (<em>Triturus cristatus</em>) using micro haematocrit capillary tubes (Carl Roth, Ø 1.6 mm) and were then stored in 80% ethanol. Total genomic DNA was extracted using the sodium dodecyl sulfate (SDS)-proteinase K/ Phenol-Chloroform extraction method. Genomic DNA was stored in Tris-EDTA buffer (10 mM Tris-HCl, 0.1 mM EDTA, pH 8.0) and used for all subsequent reactions. Each individual sample was mugenotyped for 17 microsatellite loci. Primers were combined in three multiplex mixes (Drechsler <i>et al., </i>2013). 10 µl Type-it Multiplex PCRs (Qiagen) containing 1 µl of genomic DNA were performed. The PCR profile was as follows: (1) 5 min at 95°C, (2) 30 s at 94°C, (3) 90 s at an annealing temperature of 60°C, (4) 60 s at 72°C, (5) return to step 2 for 30 times, (6) 30 min at 60°C. Obtained PCR products were diluted with 50-200 μl water depending on the strength of obtained PCR products. 1 µl of each diluted multiplex reaction was added to 20 μl of Genescan 500-LIZ size standard (Applied Biosystem) and then run on an ABI 3730 96-capillary or an ABI 3130 16-capillary automated DNA-sequencer. Allele scoring of microsatellite loci was performed using Genemarker software (SoftGenetics version 1.95).
description: Microsatellite Genotypes: Missing values are coded
 "-9". Presence/Absence Data: Missing values
 are coded "-".