Data from: Small but connected islands can maintain populations and genetic diversity under climate change
Data files
May 09, 2024 version files 8.37 KB
Abstract
In response to the striking effects of environmental change, conservation strategies often include the identification of conservation areas that can effectively maintain vulnerable species. Consequently, identifying system-specific conditions that maintain the demographic and genetic viability of species of conservation concern is essential. Connectivity plays a critical role in the persistence of populations. Islands have been model systems to understand connectivity and metapopulation processes and have emerged as particularly favorable targets for conservation. While islands can be isolated from mainland disturbances, it is unknown what degree of isolation is necessary to avoid unfavorable changes but remain sufficiently connected to maintain population viability. To test this question, we explored connectivity within the Apostle Islands, an archipelago of 22 islands within Lake Superior, by comparing historical and contemporary trends in ice bridge connectivity and by simulating the effect of reduced connectivity within this system. We developed a demographically informed individual-based model to explicitly test the role of connectivity to influence the persistence and genetic diversity of American marten (Martes americana), a forest carnivore at risk across its southern range boundary. We found that genetic diversity was resilient to moderate changes in ice cover, but a complete loss of connectivity resulted in rapid genetic erosion. Despite genetic erosion, populations persisted as long as nominal connectivity occurred between islands. Our work suggests that connectivity will decline, but martens would be resilient to moderate changes, and, in the short term, the Apostle Islands can act as a refuge along this species’ southern range boundary. Identifying thresholds in connectivity that maintain populations but allow for isolation from disturbance will be necessary to identify suitable areas for species conservation across space and time.
https://doi.org/10.5061/dryad.h70rxwdsd
Summary statistics and genetic data of American martens on the Apostle Islands collected between 2017 and 2019. This dataset was used to parameterize an individual based model to infer parameters of survival and migration. Then simulate a population forward in time to track changes in genetic diversity.
Description of the data and file structure
Smith_and_Pauli_2024_Ecography_summary_statistics.csv - Observed population size, allelic richness, and observed heterozygosity by island used as summary statistics in approximate Bayesian computation to infer parameter values.
Smith_and_Pauli_2024_Ecography_starting_genotypes.csv - File contains multilocus genotypes of individuals used in the analysis with a unique ID column and island identifier. Each microsatellite marker is represented by two columns.
Smith_and_Pauli_2024_Ecography_found_allele_frequencies.csv - File contains observed allele frequencies of the founding population of the Apostle Islands. Allele frequencies were used to simulate genotypes of simulated immigrating individuals.
DATA-SPECIFIC INFORMATION FOR: Smith_and_Pauli_2024_Ecography_summary_statistics.csv
1. Number of variables: 4 columns (island/pop size/allelic richness/heterozygosity)
2. Number of cases/rows: 5
3. Variable List:
- Island - Island name within the Apostle Islands, WI, USA
- Pop size - estimated population size of martens
- Allelic richness - allelic richness estimated from 13 microsatellite markers.
- Heterozygosity - observed heterozygosity estimated from 13 microsatellite markers.
4. Missing data codes: NA
5. Specialized formats or other abbreviations used: NA
DATA-SPECIFIC INFORMATION FOR: Smith_and_Pauli_2024_Ecography_starting_genotypes.csv
1. Number of variables: 24 columns (id/pop/11 markers)
2. Number of cases/rows: 43
3. Variable List:
- id - individual marten identity
- pop - island that individual was sampled on
- 11 msat markers with 2 columns for each marker.
4. Missing data codes:-1
5. Specialized formats or other abbreviations used: NA
DATA-SPECIFIC INFORMATION FOR: Smith_and_Pauli_2024_Ecography_found_allele_frequencies.csv
1. Number of variables: 3 columns (marker/allele/frequency)
2. Number of cases/rows: 63
3. Variable List:
- Marker - name of microsatellite marker
- Allele - base pair length of allele
- Frequency - frequency of allele in founding population of martens to the Apostle Islands.
4. Missing data codes: NA
5. Specialized formats or other abbreviations used: NA
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