Title | Changes in sub-fossil chironomid assemblages in two Northern Patagonian lake systems associated to the occurrence of historical fires |
Publication Type | Journal Article |
Year of Publication | 2013 |
Authors | Araneda, A, Ortega, C, Jana, P, Torrejon, F, Bertrand, S, Vargas, P, Fagel, N, Alvarez, D, Urrutia, R |
Journal | Journal of Paleolimnology |
Volume | 50 |
Issue | 1 |
Pagination | 41-56 |
Abstract | Patagonia is commonly seen as an exceptionally pristine area because of its wildlife and practically unpolluted waters. However, during the twentieth century the burning of natural forests was one of the most important human activities in Northern Chilean Patagonia. Some estimations indicate that three million hectares were burned during the first three decades of the century. Hence the objective of this study was to evaluate the impacts of the historical fires in Lake Burgos (45º42′S) and Lake Thompson (45º38′S) in Chilean Patagonia. The impact was measured by evaluating chironomid assemblage since they are sensitive enough to be used as an indicator of aquatic ecosystem health. Fires have a direct and drastic effect on a lake watershed but also indirectly affect a lake ecosystem, changing sedimentation patterns or increasing nutrient inputs. In the studied lakes the periods with higher prevalence of fires were identified by charcoal analysis, while organic matter and magnetic susceptibility allowed the confirmation of pre-fire and post-fire periods. The chironomid composition was evaluated through a PCA and an analysis of similarity (ANOSIM) to test the significance among periods while a Detrended Correspondence Analysis was applied to the chironomid assemblage downcore to assess compositional structure and taxa turnover. In Lake Burgos the ANOSIM test indicated significant differences between the pre-fire and fire periods (p |
DOI | 10.1007/s10933-013-9703-0 |