Landscape connectivity among remnant populations of guanaco (Lama guanicoe Müller, 1776) in an arid region of Chile impacted by global change
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Abstract
Connectivity between populations plays a key role in the long-term persistence of species in fragmented habitats. It is an issue of concern for the preservation of biodiversity in drylands since landscapes in water limited environments are characterized by low habitat cover, high habitat fragmentation and harsh matrices, and are being rapidly degraded at the global scale. In this study, we modelled landscape connectivity between the 11 remnant coastal and Andean populations of the guanaco Lama guanicoe, an emblematic herbivore indigenous to South America, in Chile's arid Norte Chico. We first produced a habitat surface model to derive a regional surface resistance map; and we then used circuit theory to map functional connectivity, investigate the degree of isolation of the populations, and identify those that most contribute to the network patch connectivity. Predicted suitable habitat for L. guanicoe represented about 25% of the study region (i.e. 29,173 km2), and was heterogeneously distributed along a continuous stretch along the Andes, and discontinuous patches along the coast. As a result, we found that high connectivity current flows in the mid and high Andes formed a wide continuous connectivity corridor enabling connectivity between all the high Andean populations. Coastal populations, in contrast, were predicted to be more isolated. They only connect to medium and high altitude populations, and for two of them, animal movement was linked to the effectiveness of wildlife crossings. Based on the degree of connectivity, population size, and local threats, the coastal and the northernmost populations were identified as being most vulnerable, while the Andean populations appeared to be least at risk, even when located near areas of mining activity. Collectively, our results suggest that functional connectivity is an issue of concern for L. guanicoe in Chile’s Norte Chico, and that future conservation and management plans should adopt a landscape strategy aiming at conserving the functional connectivity between the coastal and Andean populations, and at protecting the habitat patches likely to act as stepping stones within the connectivity network.
Cite this as
2018. Landscape connectivity among remnant populations of guanaco (Lama guanicoe Müller, 1776) in an arid region of Chile impacted by global change. PeerJ Preprints 6:e3273v2 https://doi.org/10.7287/peerj.preprints.3273v2note This preprint is not peer-reviewed. You may wish to reference the subsequent peer-reviewed version of this article.
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This new version has general changes suggested by peer reviewers.
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Supplemental Information
Supplemental figure S2
Supplemental figure S2. Potential suitable habitat (suitable/unsuitable) (A) and Habitat suitability index (B) maps of Lama guanicoe across Chile’s Norte Chico. The suitable habitat threshold was defined as the habitat suitability index value that maximized the sum of sensitivity and specificity (see Methodology). Habitat patches corresponding to the guanaco populations are represented in Figure part B: 1. Pan de Azúcar National Park; 2. Nevado Tres Cruces National Park; 3. Llanos de Challe National Park; 4. Oso Negro sector; 5. El Morro; 6. Los Choros; 7. Calvario stream; 8. Tres Quebradas river; 9. El Tambo stream; 10. Estero Derecho nature sanctuary; 11. Pelambres area.
Supplementary Table S3
Food items listed according to species and vegetation communities contributing strongly to Lama guanicoe distribution in the study area
Table S4
Extinction risk level of the Lama guanicoe populations in Chile’s Norte Chico based on potential population size, local threats and connectivity extent approximated by current flow centrality values
Additional Information
Competing Interests
The authors declare that they have no competing interests.
Author Contributions
Mara Ines Espinosa Herazo conceived and designed the experiments, performed the experiments, analyzed the data, contributed reagents/materials/analysis tools, prepared figures and/or tables, authored or reviewed drafts of the paper, approved the final draft.
Nicolas Gouin conceived and designed the experiments, performed the experiments, analyzed the data, contributed reagents/materials/analysis tools, prepared figures and/or tables, authored or reviewed drafts of the paper, approved the final draft.
Francisco Antonio Squeo Porcile conceived and designed the experiments, performed the experiments, analyzed the data, contributed reagents/materials/analysis tools, prepared figures and/or tables, authored or reviewed drafts of the paper, approved the final draft.
David López Aspe conceived and designed the experiments, performed the experiments, analyzed the data, contributed reagents/materials/analysis tools, prepared figures and/or tables, authored or reviewed drafts of the paper, approved the final draft.
Angéline Bertin conceived and designed the experiments, performed the experiments, analyzed the data, contributed reagents/materials/analysis tools, prepared figures and/or tables, authored or reviewed drafts of the paper, approved the final draft.
Animal Ethics
The following information was supplied relating to ethical approvals (i.e., approving body and any reference numbers):
Servicio Agrícola y Ganadero – SAG
Field Study Permissions
The following information was supplied relating to field study approvals (i.e., approving body and any reference numbers):
Servicio Agrícola y Ganadero (SAG)
Data Deposition
The following information was supplied regarding data availability:
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Funding
This study was supported by a grant from the Institute of Ecology and Biodiversity (IEB) of Chile and the South America-Barrick Gold Corporation (RCA N° 39/2001). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.
