The authors declare no conflict of interest.
Multiple drivers of plant diversity in forest ecosystems
Article first published online: 7 MAY 2014
© 2014 John Wiley & Sons Ltd
Global Ecology and Biogeography
Volume 23, Issue 8, pages 885–893, August 2014
How to Cite
Zhang, Y., Chen, H. Y. H. and Taylor, A. (2014), Multiple drivers of plant diversity in forest ecosystems. Global Ecology and Biogeography, 23: 885–893. doi: 10.1111/geb.12188
Editor: Richard Field
- Issue published online: 4 JUL 2014
- Article first published online: 7 MAY 2014
- Natural Sciences and Engineering Research Council of Canada. Grant Numbers: DG283336-09, STPGP428641
- Early Researcher Award
- Ontario Ministry of Research and Innovation
- Forest Ecosystem Science Co-operative Inc.
- Boosted regression trees;
- intermediate disturbance hypothesis;
- productivity and diversity relationship;
- soil drainage class;
- species richness;
- species–energy relationship;
- stand age
Theoretical and empirical studies have shown that climate is a major determinant of species richness, yet the importance of climate relative to local site conditions remains unclear in forest ecosystems across large regions. Furthermore, little is known about how climate and local site conditions affect species evenness and understorey plant diversity.
Canadian forest (42°37′ to 68°14′ N; 53°25′ to 134°46′ W; 4 to 2170 m elevation).
Using national, broad-scale forest inventory data, we tested the influence of growing degree days (GDD), climate moisture index (CMI), soil drainage class (SDC) and stand age (SA) on plant diversity across Canada's forests. Diversity was assessed on variable plot sizes from 125 to 500 m2 for canopy tree and total plant species, and from 100 to 400 m2 for understorey plants.
Our models accounted for 47, 30 and 49% of total variation in canopy tree species richness, Simpson's dominance index and total plant species richness, respectively. After accounting for the effects of plot size and management history, canopy richness increased with GDD and CMI and peaked at intermediate SDC and SA. Simpson's dominance index decreased with increasing GDD and CMI and was lowest at intermediate SDC and SA. Total species richness was most strongly related to SDC and was highest on imperfectly drained soils. Climatic controls on species richness of understorey strata were generally weaker than those on canopy richness.
Our results for canopy richness along a mainly longitudinal gradient demonstrate the positive effects of energy on tree species diversity and show evidence for the effects of local site conditions and secondary succession on diversity. Furthermore, our results show that the extent of the influence of climate and local site conditions on plant species diversity can strongly differ between vegetation strata.