Fig. 13

Forest plots showing maximum negative effects on Crustacea abundance during the study period in each included study. The size of the squares is proportional to the weight of the studies, which is based on the number of replicates. Kroeger (2013) reported separate abundance data for different taxa groups, but to avoid statistical dependence we have used data for only one taxa group. To obtain a conservative estimate of negative effects the taxa group showing the least negative effect (Cyclopoida) was selected (results do not change significantly if other species are used). Data represents 13 regions (five in Europe, five in North America, two in Asia, one in Australia). Study labels refer to short reference and study name information as recorded in Additional file 6