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Quantifying patterns of change in marine ecosystem response to multiple pressures.

Large SI, Fay G, Friedland KD, Link JS - PLoS ONE (2015)

Bottom Line: The ability to understand and ultimately predict ecosystem response to multiple pressures is paramount to successfully implement ecosystem-based management.We used ecological indicators, synthetic measures of ecosystem status and functioning, to enumerate important ecosystem attributes and to reduce the complexity of the Northeast Shelf Large Marine Ecosystem (NES LME).Although present, threshold shifts in ecosystem response to environmental pressures were much less important, which suggests that anthropogenic pressures have significantly altered the ecosystem structure and functioning of the NES LME.

View Article: PubMed Central - PubMed

Affiliation: NOAA-Fisheries, Woods Hole, Massachusetts, United States of America.

ABSTRACT
The ability to understand and ultimately predict ecosystem response to multiple pressures is paramount to successfully implement ecosystem-based management. Thresholds shifts and nonlinear patterns in ecosystem responses can be used to determine reference points that identify levels of a pressure that may drastically alter ecosystem status, which can inform management action. However, quantifying ecosystem reference points has proven elusive due in large part to the multi-dimensional nature of both ecosystem pressures and ecosystem responses. We used ecological indicators, synthetic measures of ecosystem status and functioning, to enumerate important ecosystem attributes and to reduce the complexity of the Northeast Shelf Large Marine Ecosystem (NES LME). Random forests were used to quantify the importance of four environmental and four anthropogenic pressure variables to the value of ecological indicators, and to quantify shifts in aggregate ecological indicator response along pressure gradients. Anthropogenic pressure variables were critical defining features and were able to predict an average of 8-13% (up to 25-66% for individual ecological indicators) of the variation in ecological indicator values, whereas environmental pressures were able to predict an average of 1-5 % (up to 9-26% for individual ecological indicators) of ecological indicator variation. Each pressure variable predicted a different suite of ecological indicator's variation and the shapes of ecological indicator responses along pressure gradients were generally nonlinear. Threshold shifts in ecosystem response to exploitation, the most important pressure variable, occurred when commercial landings were 20 and 60% of total surveyed biomass. Although present, threshold shifts in ecosystem response to environmental pressures were much less important, which suggests that anthropogenic pressures have significantly altered the ecosystem structure and functioning of the NES LME. Gradient response curves provide ecologically informed transformations of pressure variables to explain patterns of ecosystem structure and functioning. By concurrently identifying thresholds for a suite of ecological indicator responses to multiple pressures, we demonstrate that ecosystem reference points can be evaluated and used to support ecosystem-based management.

No MeSH data available.


Related in: MedlinePlus

Biplot of the first two principal components display the coordinate positions and connecting segments for each year and indicating inferred compositional patterns.Environmental and anthropogenic pressure variables used in the analysis displayed as vectors.
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pone.0119922.g005: Biplot of the first two principal components display the coordinate positions and connecting segments for each year and indicating inferred compositional patterns.Environmental and anthropogenic pressure variables used in the analysis displayed as vectors.

Mentions: Using cumulative importance functions (Fig. 3), shifts in ecological indicator value along pressure gradients can be mapped in multivariate space using principal component analysis (PCA; sensu Fig. 5 in [29]). The first two principal components account for 94.59% of the total variance. Coordinate position represents inferred ecosystem compositions, as associated with the anthropogenic and environmental pressure variables, as vectors. Each coordinate position is linked by a line segment to facilitate comparison as a time-series. Given the coordinate position of the inferred ecosystem compositions, two distinct groupings of data emerge: 1965–1977 and 1978–2010 (Fig. 5). Pressure variable vectors further indicate that exploitation, landings, and 1-yr lagged landings are important in defining this difference, which accounts for 89.5% of the explained variation. Both groupings vary according to the 2nd PCA axis representative of environmental pressure variables, however, this axis only accounts for 4% of the explained variation.


Quantifying patterns of change in marine ecosystem response to multiple pressures.

Large SI, Fay G, Friedland KD, Link JS - PLoS ONE (2015)

Biplot of the first two principal components display the coordinate positions and connecting segments for each year and indicating inferred compositional patterns.Environmental and anthropogenic pressure variables used in the analysis displayed as vectors.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4362946&req=5

pone.0119922.g005: Biplot of the first two principal components display the coordinate positions and connecting segments for each year and indicating inferred compositional patterns.Environmental and anthropogenic pressure variables used in the analysis displayed as vectors.
Mentions: Using cumulative importance functions (Fig. 3), shifts in ecological indicator value along pressure gradients can be mapped in multivariate space using principal component analysis (PCA; sensu Fig. 5 in [29]). The first two principal components account for 94.59% of the total variance. Coordinate position represents inferred ecosystem compositions, as associated with the anthropogenic and environmental pressure variables, as vectors. Each coordinate position is linked by a line segment to facilitate comparison as a time-series. Given the coordinate position of the inferred ecosystem compositions, two distinct groupings of data emerge: 1965–1977 and 1978–2010 (Fig. 5). Pressure variable vectors further indicate that exploitation, landings, and 1-yr lagged landings are important in defining this difference, which accounts for 89.5% of the explained variation. Both groupings vary according to the 2nd PCA axis representative of environmental pressure variables, however, this axis only accounts for 4% of the explained variation.

Bottom Line: The ability to understand and ultimately predict ecosystem response to multiple pressures is paramount to successfully implement ecosystem-based management.We used ecological indicators, synthetic measures of ecosystem status and functioning, to enumerate important ecosystem attributes and to reduce the complexity of the Northeast Shelf Large Marine Ecosystem (NES LME).Although present, threshold shifts in ecosystem response to environmental pressures were much less important, which suggests that anthropogenic pressures have significantly altered the ecosystem structure and functioning of the NES LME.

View Article: PubMed Central - PubMed

Affiliation: NOAA-Fisheries, Woods Hole, Massachusetts, United States of America.

ABSTRACT
The ability to understand and ultimately predict ecosystem response to multiple pressures is paramount to successfully implement ecosystem-based management. Thresholds shifts and nonlinear patterns in ecosystem responses can be used to determine reference points that identify levels of a pressure that may drastically alter ecosystem status, which can inform management action. However, quantifying ecosystem reference points has proven elusive due in large part to the multi-dimensional nature of both ecosystem pressures and ecosystem responses. We used ecological indicators, synthetic measures of ecosystem status and functioning, to enumerate important ecosystem attributes and to reduce the complexity of the Northeast Shelf Large Marine Ecosystem (NES LME). Random forests were used to quantify the importance of four environmental and four anthropogenic pressure variables to the value of ecological indicators, and to quantify shifts in aggregate ecological indicator response along pressure gradients. Anthropogenic pressure variables were critical defining features and were able to predict an average of 8-13% (up to 25-66% for individual ecological indicators) of the variation in ecological indicator values, whereas environmental pressures were able to predict an average of 1-5 % (up to 9-26% for individual ecological indicators) of ecological indicator variation. Each pressure variable predicted a different suite of ecological indicator's variation and the shapes of ecological indicator responses along pressure gradients were generally nonlinear. Threshold shifts in ecosystem response to exploitation, the most important pressure variable, occurred when commercial landings were 20 and 60% of total surveyed biomass. Although present, threshold shifts in ecosystem response to environmental pressures were much less important, which suggests that anthropogenic pressures have significantly altered the ecosystem structure and functioning of the NES LME. Gradient response curves provide ecologically informed transformations of pressure variables to explain patterns of ecosystem structure and functioning. By concurrently identifying thresholds for a suite of ecological indicator responses to multiple pressures, we demonstrate that ecosystem reference points can be evaluated and used to support ecosystem-based management.

No MeSH data available.


Related in: MedlinePlus