Comparing wetlands repeatedly sampled in spring (high and summer (environmental water) revealed that average abundance of calling males at wetlands was significantly higher in spring than in summer (p = 0.005) (Figure 36A). Average frog species call richness was also significantly higher in spring than in summer 2012 (p<0.001) (Figure 36B)(Appendix VIII). Figure 36. Mean (± Standard Error) (a) abundance and (b) species richness of calling males at wetlands (n = 9) in spring (high flows) and summer (environmental water) 2012. Comparison of environmental variables at wetlands sampled during spring (high flows) and summer (environmental water) 2012 frog surveys revealed that flow to South Australia, and emergent vegetation decreased significantly from spring to summer and air temperature increased significantly over the sampling period (Hoffmann et al. 2014). Emergent vegetation was positively correlated with flows to South Australia (r2 = 0.28, p = 0.028, n = 18). Electrical conductivity, humidity and submerged vegetation were not significantly different between spring and summer surveys. Both frog call abundance and species call richness displayed a positive relationship with emergent vegetation (Figure 37 and Figure 38). Generalised linear modelling revealed that flows to South Australia and emergent vegetation were significant predictors for frog call abundance and species call richness at wetlands (Appendix IX and Appendix X)). Overall, the included environmental variables explained 62.4% and 46.7% of the variation in frog call abundance and species richness respectively. Figure 37. Relationship between species richness of calling males and emergent vegetation (%) at wetlands in spring and summer 2012. Figure 38. Relationship between the abundance of calling males and emergent vegetation (%) at wetlands in spring and summer 2012.
Comparing wetlands repeatedly sampled in spring (high and summer (environmental water) revealed that average abundance of calling males at wetlands was significantly higher in spring than in summer (p = 0.005) (Figure 36A). Average frog species call richness was also significantly higher in spring than in summer 2012 (p<0.001) (Figure 36B)(Appendix VIII). Figure 36. Mean (± Standard Error) (a) abundance and (b) species richness of calling males at wetlands (n = 9) in spring (high flows) and summer (environmental water) 2012. Comparison of environmental variables at wetlands sampled during spring (high flows) and summer (environmental water) 2012 frog surveys revealed that flow to South Australia, and emergent vegetation decreased significantly from spring to summer and air temperature increased significantly over the sampling period (Hoffmann et al. 2014). Emergent vegetation was positively correlated with flows to South Australia (r2 = 0.28, p = 0.028, n = 18). Electrical conductivity, humidity and submerged vegetation were not significantly different between spring and summer surveys. Both frog call abundance and species call richness displayed a positive relationship with emergent vegetation (Figure 37 and Figure 38). Generalised linear modelling revealed that flows to South Australia and emergent vegetation were significant predictors for frog call abundance and species call richness at wetlands (Appendix IX and Appendix X)). Overall, the included environmental variables explained 62.4% and 46.7% of the variation in frog call abundance and species richness respectively. Figure 37. Relationship between species richness of calling males and emergent vegetation (%) at wetlands in spring and summer 2012. Figure 38. Relationship between the abundance of calling males and emergent vegetation (%) at wetlands in spring and summer 2012.
ecological-response-monitoring-lower-murray-2012-13-final-report.docx