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Effects of tree mortality on the spatial patterns and interspecific associations of plant species in a Quercus aliena var. acuteserrata forest in Baotianman,Henan, China |
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| Affiliation: | College of Life Sciences, Henan Agricultural University, Zhengzhou 450002, China Huaxian Environmental Protection Agency, Huaxian, Henan 456400, China and Henan College of Finance and Taxation, Zhengzhou 451464, China |
| Abstract: | Aims Tree mortality is an important ecological process in forest ecosystems. The aims of this study were to determine how tree mortality influences the spatial patterns and interspecific associations of plant species, and what are the causes of tree mortality in a 1 hm2 permanent plot in Baotianman National Nature Reserve, Nanyang City, Henan Province. Methods We conducted field investigations in the plot and used spatial point pattern analysis to examine the spatial patterns and interspecific associations of 17 species prior to and following mortality. Important findings (1) Most of the species in the study plot showed an aggregated distribution both pre- and post-mortality. However, the number of species showing aggregated distribution decreased and the number of species showing random distribution increased following the mortality event. (2) Most species were positively associated with Quercus aliena var. acuteserrata both pre- and post-mortality, while some had no apparent association. Following tree mortality, on fine scales, the number of species with positive associations increased, and the number of species with negative associations decreased. (3) Tree mortality was in consistency with the random death hypothesis. The interspecific associations of four species with Q. aliena var. acuteserrata completely changed following death. For most species, the spatial patterns and the interspecific association with Q. aliena var. acuteserrata either changed at minor scales or did not change. The variations in spatial patterns or interspecific associations were inconsistent among species. (4) The dead trees of Q. aliena var. acuteserrata were significantly associated with the living trees in 13 species, but the associations between dead and living trees were not in agreement with the changes in interspecific association following mortality. Only five living tree species competed with the dead trees of Q. aliena var. acuteserrata, and the competition between each of these species and Q. aliena var. acuteserrata intensified after individual death. Tree mortality is the result of a variety of factors. Although the tree mortality in the study plot was in accordance with the random death hypothesis, there were also a few individuals which were dead from competition. |
| Keywords: | mortality random death hypothesis spatial patterns interspecific associations Quercus aliena var Quercus aliena var" target="_blank"> acuteserrata')">Quercus aliena var acuteserrata |
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