Articulo
Species-specific phenological trends in shallow Pampean lakes (Argentina) zooplankton driven by contemporary climate change in the Southern Hemisphere
Autor
Diovisalvi, Nadia Rosalia
Odriozola, Mariana Paola
García de Souza, Javier Ricardo
Rojas Molina, Florencia Mercedes
Fontanarrosa, María Soledad
Escaray, Roberto Ulises
Bustingorry, Jose Fernando
Sanzano, Pablo Miguel
Grosman, Manuel Fabián
Zagarese, Horacio Ernesto
Institución
Resumen
The relationship between the timing of recurrent biological events and seasonal climatic patterns (i.e., phenology) is a crucial ecological process. Changes in phenology are increasingly linked to global climate change. However, current evidence of phenological responses to recent climate change is subjected to substantial regional and seasonal biases. Most available evidence on climate-driven phenological changes comes from Northern Hemisphere (NH) ecosystems and typically involves increases in spring and summer temperatures, which translate into earlier onsets of spring population developments. In the Argentine Pampa region, warming has occurred at a much slower pace than in the NH, and trends are mostly restricted to increases in the minimum temperatures. We used zooplankton abundance data from Lake Chascomús (recorded every two weeks from 2005 to 2015) to evaluate potential changes in phenology. We adopted a sequential screening approach to identify taxa displaying phenological trends and evaluated whether such trends could be associated to observe long-term changes in water temperature. Two zooplankton species displayed significant later shifts in phenology metrics (end date of <i>Brachionus havanaensis</i> seasonal distribution: 31 day/decade, onset and end dates of <i>Keratella americana</i> seasonal distribution: 59 day/decade and 82 day/decade, respectively). The timing of the observed shift in <i>B. havanaensis</i> phenology was coincident with a warming trend in the May lake water temperature (4.7°C per decade). Analysis of abundance versus temperature patterns from six additional shallow Pampean lakes, and evaluation of previous experimental results, provided further evidence that the lake water warming trend in May was responsible for the delayed decline of <i>B. havanaensis</i> populations in autumn. This study is the first report of freshwater zooplankton phenology changes in the Southern Hemisphere (SH). Instituto de Limnología "Dr. Raúl A. Ringuelet"