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Decline of dry grassland specialists in M editerranean high‐mountain communities influenced by recent climate warming
Author(s) -
JiménezAlfaro Borja,
Gavilán Rosario G.,
Escudero Adrián,
Iriondo José María,
FernándezGonzález Federico
Publication year - 2014
Publication title -
journal of vegetation science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.1
H-Index - 115
eISSN - 1654-1103
pISSN - 1100-9233
DOI - 10.1111/jvs.12198
Subject(s) - generalist and specialist species , grassland , species richness , altitude (triangle) , ecology , climate change , geography , global warming , community structure , physical geography , habitat , biology , geometry , mathematics
Questions What changes have occurred in M editerranean high‐mountain communities during the last 50 yr? Do these changes reflect upward shifts and decline in dry grassland specialists due to climate warming? Location Upper belt (1900–2400 m a.s.l.) in S ierra de G uadarrama, S pain. Methods We re‐surveyed dry grassland communities in 50 summits that were previously sampled between the 1960s and 1980s. New plots were placed in the same localities and the same conditions as the original surveys. Changes at the species level were evaluated by comparing, between the two survey periods, species frequencies and optimal altitude estimated by local distribution models done with Maxent. Changes at the community level were assessed by comparing species richness and composition of the two surveys in relation to altitude, plot size and time between surveys. We evaluated observed changes in the whole data set and species groups by structuring the species into dry grassland specialists, other alpine species and generalists occurring at wider altitudinal ranges. Results There was a general decline in the frequency of dry grassland specialists, an increase in frequency of generalists and no clear trends in the other species. Upward shifts were mainly detected in generalists, with significant increases in frequency. At the community level, we found a general increase in species richness that was mainly determined by the increase in generalists; coupled with a decline in number of dry grassland specialists. The structure of the communities evidenced changes between the historical surveys and the re‐survey, which were mainly correlated with the number of years and the increasing dominance of generalists. Conclusions In contrast with trends observed in other Mediterranean high‐mountain communities, our study reports a general increase in species richness, although this effect is concurrent with a decline in dry grassland specialists. The observed trends support on‐going replacement of endemic species by low‐altitude species, and associated changes in community assemblages. Despite the limitations of re‐visitation studies for assessing climate‐driven changes, our results highlight the necessity of developing more studies for assessing the effects of drought in Mediterranean high‐mountain communities.