Journal
ECOLOGICAL INDICATORS
Volume 77, Issue -, Pages 14-22Publisher
ELSEVIER SCIENCE BV
DOI: 10.1016/j.ecolind.2017.01.038
Keywords
Indicator; Mean size; Abundance; ROC; AUC; Baltic Sea
Categories
Funding
- Maj and Tor Nessling Foundation [201600194]
- DEVOTES (DEVelopment Of innovative Tools for understanding marine biodiversity and assessing Good Environmental Status)
- European Union under 7th Framework Programme [308392]
- BONUS BIO-C3
- BONUS (Art 185) - EU
- Academy of Finland
Ask authors/readers for more resources
Indicators are used to help managers to conserve biodiversity and guarantee the sustainable use of marine resources. Good indicators are scientifically valid, ecologically relevant, respond to pressures, and it is possible to set target levels for them. Zooplankton is an important link in the food web as it transfers energy from primary producers (phytoplankton) to planktivorous fish, including the commercially important herring in the Baltic Sea. Eutrophication is known to increase zooplankton abundance and decrease the mean size of zooplankton individuals, while particularly herring prefers larger zooplankton as prey. Therefore, both the abundance/biomass and the size structure of the zooplankton community are highly relevant for the functioning of the pelagic food web, and their combination has been proposed as an indicator of the status of the pelagic food web. In this study, we evaluated the indicator performance of zooplankton abundance and mean size in the northern Baltic Sea using signal detection theory and annual zooplankton monitoring data from years 1979-2014. Herring weight-at-age and chlorophyll a levels were used to estimate the reference periods or gold standard of the food web status. The sensitivity and specificity of the indicator was evaluated using ROC curves. Thresholds were set and evaluated with positive and negative predictive values for the zooplankton mean size in three sub-basins of the Baltic Sea. The results suggest that zooplankton mean size is able to reflect the state of the food web in the Baltic Sea. Our study also confirms that signal detection theory is useful in evaluating ecological indicators with clear pressures. However, with parameters that are affected by multiple contrary pressures, such as zooplankton abundance, ROC curves cannot offer enough information about the performance of an indicator parameter. (C) 2017 Elsevier Ltd. All rights reserved.
Authors
I am an author on this paper
Click your name to claim this paper and add it to your profile.
Reviews
Recommended
No Data Available