caa a22 4500 467885990 CHVBK 20180406152734.0 cr unu---uuuuu 170328e20060801xx s 000 0 eng 10.1007/s10021-005-0065-y doi (NATIONALLICENCE)springer-10.1007/s10021-005-0065-y Detecting Stress at the Whole-Ecosystem Level: The Case of a Mountain Lake (Lake Santo, Italy) [Elektronische Daten] [Cristina Bondavalli, Antonio Bodini, Giampaolo Rossetti, Stefano Allesina] Detecting the early signs of stress is imperative for the conservation of natural ecosystems. They may, however, go unrecognized because ecosystems, when disturbed, may act as sinks that absorb the external impact without showing any evident changes. This seems to be the case for Lake Santo, a small water body located in a mountainous area of northern Italy. Tourism activity in this area began to develop in the early 1970s and grew continuously over the following 20 years. This activity caused a continually increasing nutrient load into the waters, but surprisingly the lake has remained oligo-mesotrophic, as it was before human pressure became a stressor to the lake. To anticipate possible severe damage to the ecosystem, we searched for early signs of stress by carrying out a retrospective analysis based on a whole-ecosystem approach using trophic flow networks. Ecosystem properties of the lake as calculated from network analysis for the disturbed (year 1991) and unimpacted (year 1973) configurations were compared, with the support of sensitivity analysis and statistical tests. We found evidence that in the period 1970-90 nutrient enrichment did change the course of normal development as the observed increase in system throughput was accompanied by a drop in the level of mutual organization of flows, which instead would be expected to increase during the natural progression of the ecosystem. The scenario that emerged from the comparison of system-level indices, cycling activity, trophic structure, and trophic efficiency indicates that the ecosystem has been subjected to stress. In particular, the type of disturbance corresponds to a quantitative definition of eutrophication. Springer Science+Business Media, Inc., 2006 ecosystem development nationallicence lake ecosystem nationallicence network analysis nationallicence nutrient cycling nationallicence stressed ecosystem nationallicence system-level trends nationallicence trophic analysis nationallicence Bondavalli Cristina Department of Environmental Sciences, University of Parma, Parco Area delle Scienze, 33/A, 43100, Parma, Italy aut Bodini Antonio Department of Environmental Sciences, University of Parma, Parco Area delle Scienze, 33/A, 43100, Parma, Italy aut Rossetti Giampaolo Department of Environmental Sciences, University of Parma, Parco Area delle Scienze, 33/A, 43100, Parma, Italy aut Allesina Stefano Department of Environmental Sciences, University of Parma, Parco Area delle Scienze, 33/A, 43100, Parma, Italy aut Ecosystems Springer-Verlag; www.springer-ny.com 9/5(2006-08-01), 768-787 1432-9840 9:5<768 2006 9 10021 https://doi.org/10.1007/s10021-005-0065-y text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1007/s10021-005-0065-y text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Bondavalli Cristina Department of Environmental Sciences, University of Parma, Parco Area delle Scienze, 33/A, 43100, Parma, Italy aut NATIONALLICENCE 700 1- Bodini Antonio Department of Environmental Sciences, University of Parma, Parco Area delle Scienze, 33/A, 43100, Parma, Italy aut NATIONALLICENCE 700 1- Rossetti Giampaolo Department of Environmental Sciences, University of Parma, Parco Area delle Scienze, 33/A, 43100, Parma, Italy aut NATIONALLICENCE 700 1- Allesina Stefano Department of Environmental Sciences, University of Parma, Parco Area delle Scienze, 33/A, 43100, Parma, Italy aut NATIONALLICENCE 773 0- Ecosystems Springer-Verlag; www.springer-ny.com 9/5(2006-08-01), 768-787 1432-9840 9:5<768 2006 9 10021 Metadata rights reserved Springer special CC-BY-NC licence nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer