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Research article - Peer-reviewed, 2021

Unravelling the mechanisms of spatial correlation between species and size diversity in forest ecosystems

Pommerening, Arne; Zhang, Gongqiao; Zhang, Xiaohong


With ongoing climate change at global scale we are currently losing biodiversity at an unprecedented rate. The insurance hypothesis and associated research, however, suggest that biodiversity has a major stabilising effect in ecosystems. In this situation, it is crucial to develop a better understanding of natural processes of maintaining biodiversity for employing them in conservation practice. In forest ecosystems, spatial species and size diversity are important aspects of α-diversity at woodland community and species population level. Both aspects of spatial diversity stem from complex relationships between tree interaction, disturbances and subsequent waves of colonisation by tree seedlings of various species. Using point process statistics, particularly the mark mingling function and the mark variogram, we studied the processes causing spatial correlations of species and size diversity. We found that spatial species dispersal and conspecific size distributions are key drivers of spatial species-size correlations and that a combination of simple random size-labelling techniques applied to mark variograms is instrumental in efficiently diagnosing them. If size ranges differ between species, spatial size diversity is largely a function of spatial species mingling. The existence of these correlations is crucial to conservation because they imply that conservation efforts can be rationalised: It is possible to focus on only one of the two tree diversity aspects. Interestingly, in multi-species forest ecosystems, although general species diversity is high, spatial species-size correlations can be diluted, because some of the many species populations may have similar size distributions.


Insurance hypothesis; Plant-plant interactions; Point process statistics; Mark mingling function; Mark variogram; Random-labelling test

Published in

Ecological Indicators
2021, volume: 121, article number: 106995

Authors' information

Swedish University of Agricultural Sciences, Department of Forest Ecology and Management
Zhang, Gongqiao
Research Institute of Forestry, CAF
Zhang, Xiaohong
Chinese Academy of Forestry

Sustainable Development Goals

SDG15 Life on land

UKÄ Subject classification


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