Niche and interspecific association of dominant tree populations of <em>Zelkova schneideriana</em> communities in eastern China

Abstract

Background: Zelkova schneideriana Hand.-Mazz., is an endangered species mainly distributed in subtropical China. Currently, little is known about its niche and interspecific association. Questions: What are the niche characteristics of Z. schneideriana and other associated species? What are the interspecific associations between these species? Study sites and dates: Z. schneideriana communities in Jiangsu, China in 2019. Methods: Twenty-one 400 m2 plots were studied for importance value, niche breadth and overlap, interspecific association of Z. schneideriana communities. Results: In 39 species of tree layer, Z. schneideriana had the greatest importance value and niche breadth. For the first 10 dominant species, a considerable difference was detected by the Levins index (1.75 - 19.84) and Shannon-Wiener index (0.77 - 3.02). Forty-four out of the 45 species pairs had the value of niche similarity indices ≤ 0.5; 38 species pairs had the value of niche overlap indices ≤ 0.5. Overall interspecific association was not a significantly negative association for variance ratio < 1. χ2 test and Spearman’s correlation coefficient further revealed that above 60 % of species pairs had negative associations, suggesting most dominant species were slightly associated with other species or even independent. Conclusions: Z. schneideriana was a constructive species. Dissimilarity in environmental requirements was found among most dominant tree species, thus decreasing competition. This is likely due to the unstable community in the early stage of succession.

Keywords

• importance value
• interspecific association
• niche breadth
• niche overlap
• Zelkova schneideriana