TY - JOUR
T1 - Long-term change in the biotic integrity of a shallow tropical lake
T2 - A decadal analysis of the Lake Chapala fish community
AU - Moncayo-Estrada, Rodrigo
AU - Lyons, John
AU - Escalera-Gallardo, Carlos
AU - Lind, Owen T.
N1 - Funding Information:
We thank J. Morales-Castellanos for extremely helpful support in field work. The research upon which this paper is based was supported by the Bob Gardner Memorial Grant Award and the Jack and Norma Folmar Endowment Fund Research Award from Baylor University, and The Explorers Club Research Award to R. Moncayo-Estrada. Rodrigo Moncayo-Estrada and Carlos Escalera-Gallardo are supported by the Comisión de Operación y Fomento de Activi-dades Académicas (COFAA) and Estímulo al Desempeño Académico (EDI).
PY - 2012/3/1
Y1 - 2012/3/1
N2 - We describe the successful application of a 4-decade analysis of an Index of Biotic Integrity (IBI) demonstrating its assessment value when applied to the fish community of Lake Chapala. We based our analysis on fish community and fishery composition and on the proportion and density of native and exotic species for each decade. Fisheries landings and IBI values document a long-term downward trend since the 1970s. Data from the 1990s and 2000s reveal a dramatic drop in the IBI score to 20 points (out of a possible 100), a rating of very poor. The fisheries collapse and the loss of 11 native species as a consequence of habitat degradation and invasive species have reduced native fish biomass and richness. Fluctuations in rainfall, principally, and water-extraction related to human activities have had a major impact on the lake. Additionally, water quality deterioration has been caused by a lack of wastewater treatment. The fish community has been further modified by large increases in the number and biomass of exotic fishes. Although the exact degree of decline in biotic integrity is impossible to determine because of uncertainty about the representativeness and accuracy of some historical information, the analysis of the temporal changes in the IBI provides compelling evidence for an accelerating drop in ecosystem health. The application of IBI, which is broad in scope and has flexible data requirements, can serve as a template for assessing trends in other water bodies with a history of fisheries data but limited standardized monitoring of the fish community.
AB - We describe the successful application of a 4-decade analysis of an Index of Biotic Integrity (IBI) demonstrating its assessment value when applied to the fish community of Lake Chapala. We based our analysis on fish community and fishery composition and on the proportion and density of native and exotic species for each decade. Fisheries landings and IBI values document a long-term downward trend since the 1970s. Data from the 1990s and 2000s reveal a dramatic drop in the IBI score to 20 points (out of a possible 100), a rating of very poor. The fisheries collapse and the loss of 11 native species as a consequence of habitat degradation and invasive species have reduced native fish biomass and richness. Fluctuations in rainfall, principally, and water-extraction related to human activities have had a major impact on the lake. Additionally, water quality deterioration has been caused by a lack of wastewater treatment. The fish community has been further modified by large increases in the number and biomass of exotic fishes. Although the exact degree of decline in biotic integrity is impossible to determine because of uncertainty about the representativeness and accuracy of some historical information, the analysis of the temporal changes in the IBI provides compelling evidence for an accelerating drop in ecosystem health. The application of IBI, which is broad in scope and has flexible data requirements, can serve as a template for assessing trends in other water bodies with a history of fisheries data but limited standardized monitoring of the fish community.
KW - biotic integrity
KW - environmental trends
KW - fisheries
KW - habitat degradation
KW - historical information
UR - http://www.scopus.com/inward/record.url?scp=84859115447&partnerID=8YFLogxK
U2 - 10.1080/07438141.2012.661029
DO - 10.1080/07438141.2012.661029
M3 - Artículo
SN - 0743-8141
VL - 28
SP - 92
EP - 104
JO - Lake and Reservoir Management
JF - Lake and Reservoir Management
IS - 1
ER -