Abstract
The classical environmental control model assumes that species distribution is determined by the spatial variation of underlying habitat conditions. This niche-based model has recently been challenged by the neutral theory of biodiversity which assumes that ecological drift is a key process regulating species coexistence. Understanding the mechanisms that maintain biodiversity in communities critically depends on our ability to decompose the variation of diversity into the contributions of different processes affecting it. Here we investigated the effects of pure habitat, pure spatial, and spatially structured habitat processes on the distributions of species richness and species composition in a recently established 24-ha stem-mapping plot in the subtropical evergreen broad-leaved forest of Gutianshan National Nature Reserve in East China. We used the new spatial analysis method of principal coordinates of neighbor matrices (PCNM) to disentangle the contributions of these processes. The results showed that (1) habitat and space jointly explained approximately 53% of the variation in richness and approximately 65% of the variation in species composition, depending on the scale (sampling unit size); (2) tree diversity (richness and composition) in the Gutianshan forest was dominantly controlled by spatially structured habitat (24%) and habitat-independent spatial component (29%); the spatially independent habitat contributed a negligible effect (6%); (3) distributions of richness and species composition were strongly affected by altitude and terrain convexity, while the effects of slope and aspect were weak; (4) the spatial distribution of diversity in the forest was dominated by broad-scaled spatial variation; (5) environmental control on the one hand and unexplained spatial variation on the other (unmeasured environmental variables and neutral processes) corresponded to spatial structures with different scales in the Gutianshan forest plot; and (6) five habitat types were recognized; a few species were statistically significant indicators of three of these habitats, whereas two habitats had no significant indicator species. The results suggest that the diversity of the forest is equally governed by environmental control (30%) and neutral processes (29%). In the fine-scale analysis (10 x 10 m cells), neutral processes dominated (43%) over environmental control (20%).
Abstract from the paper’s OpenAlex record, shown for indexing and research. Copyright remains with the authors or the publisher. Read at the source ↗
The text the model read, with the source record’s inline markup (italics, sub- and superscripts) rendered and its character entities decoded; quote offsets refer to the raw text.
Claims 16
Claim · model-written summary
Habitat and space jointly explained about 53% of species richness variation, depending on sampling scale.
Not reportedTaxonSetting
Verbatim
e0“habitat and space jointly explained approximately 53% of the variation in richness”
Claim · model-written summary
Habitat and space jointly explained about 65% of species composition variation, depending on sampling scale.
- Outcome
- variation in species compositione0
- Direction
- explainede0
- Value
- approximately 65%e0
- Qualifier
- depending on the scale (sampling unit size)e0
Not reportedTaxonSetting
Verbatim
e0“habitat and space jointly explained approximately 53% of the variation in richness and approximately 65% of the variation in species composition, depending on the scale (sampling unit size)”
Claim · model-written summary
Spatially structured habitat accounted for 24% of tree diversity in the Gutianshan forest.
Verbatim
e0“tree diversity (richness and composition) in the Gutianshan forest was dominantly controlled by spatially structured habitat (24%)”
Claim · model-written summary
A habitat-independent spatial component accounted for 29% of tree diversity in the Gutianshan forest.
Verbatim
e0“tree diversity (richness and composition) in the Gutianshan forest was dominantly controlled by spatially structured habitat (24%) and habitat-independent spatial component (29%)”
Claim · model-written summary
Spatially independent habitat contributed a negligible 6% to tree diversity.
Not reportedTaxonSetting
Verbatim
e0“the spatially independent habitat contributed a negligible effect (6%)”
Claim · model-written summary
Altitude and terrain convexity strongly affected richness and species composition.
Not reportedTaxonSetting
Verbatim
e0“distributions of richness and species composition were strongly affected by altitude and terrain convexity”
Claim · model-written summary
Slope and aspect had weak effects on richness and species composition.
Not reportedTaxonSetting
Verbatim
e0“the effects of slope and aspect were weak”
Claim · model-written summary
Broad-scale spatial variation dominated the forest diversity distribution.
Not reportedTaxon
Verbatim
e0“the spatial distribution of diversity in the forest was dominated by broad-scaled spatial variation”
Claim · model-written summary
Environmental control and unexplained spatial variation corresponded to different spatial scales in the Gutianshan plot.
Not reportedTaxon
Verbatim
e0“environmental control on the one hand and unexplained spatial variation on the other (unmeasured environmental variables and neutral processes) corresponded to spatial structures with different scales in the Gutianshan forest plot”
Claim · model-written summary
Five habitat types were recognized in the forest plot.
Not reportedTaxon
Verbatim
e0“five habitat types were recognized”
Claim · model-written summary
A few species were significant indicators of three habitat types.
Not reportedSetting
Verbatim
e0“a few species were statistically significant indicators of three of these habitats”
Claim · model-written summary
Two habitat types had no significant indicator species.
Verbatim
e0“two habitats had no significant indicator species”
Claim · model-written summary
Environmental control accounted for 30% of forest diversity.
Not reportedTaxonSetting
Verbatim
e0“diversity of the forest is equally governed by environmental control (30%) and neutral processes (29%)”
Claim · model-written summary
Neutral processes accounted for 29% of forest diversity.
Not reportedTaxonSetting
Verbatim
e0“diversity of the forest is equally governed by environmental control (30%) and neutral processes (29%)”
Claim · model-written summary
At a 10 x 10 m scale, neutral processes accounted for 43%, dominating environmental control.
Not reportedTaxonSetting
Verbatim
e0“In the fine-scale analysis (10 x 10 m cells), neutral processes dominated (43%) over environmental control (20%)”
Claim · model-written summary
At a 10 x 10 m scale, environmental control accounted for 20%, below neutral processes.
Not reportedTaxonSetting
Verbatim
e0“In the fine-scale analysis (10 x 10 m cells), neutral processes dominated (43%) over environmental control (20%)”