Figure 3 in Life in the extreme environment: Structure and species richness of bird assemblages on Yuzhny Island of Novaya Zemlya, Russia

Figure 3. Species diversity of bird assemblages on Yuzhny Island of Novaya Zemlya. (A) Bi-plot of detrended correspondence analysis (DCA) with supplementary variables, showing the ordination of species and environmental variables. Circles indicate bird species abundance (categorical estimations by using a logarithmic scale, see Table 3), abundances decrease with increasing distance from each point in a unimodal fashion (ter Braak and Smilauer, 2002). Data represent independent samples from various habitats (n = 10). Total variation is 2.44, supplementary variables account for 66.1% (adjusted explained variation is 23.8%). Eigenvalues (lambda) are 0.675, 0.162, 0.069, and 0.025 for first (horizontal), second (vertical), third and fourth axes, respectively. The first two axes explain 34.4% of the variation. The pseudo-canonical correlations of bird abundance and environmental variables for axes 1 and 2 are 0.77 and 0.91, respectively. For an explanation of environmental variables, see Table 4. For abbreviations of species names see Fig. 4. (B) Bi-plot of the same analysis revealing the ordination of species richness over a range of habitats and environmental variables. Circles indicate bird assemblages in primary types of habitats (size of each circle corresponds to the number of bird species). The red numbers near the circles indicate species richness. The black numbers near the circles (01–10) indicate the codes of habitat types (see Fig. 4 and Table 2 for detail).