Species co-occurrence shapes spatial variability in plant diversity–biomass relationships in natural rangelands under different grazing intensities.

Sayer, Emma (2021) Species co-occurrence shapes spatial variability in plant diversity–biomass relationships in natural rangelands under different grazing intensities. Land Degradation and Development, 32 (15). pp. 4390-4401. ISSN 1085-3278

[img]
Text (Sanaei et al_LDD_preprint)
Sanaei_et_al_LDD_preprint.pdf - Accepted Version
Available under License Creative Commons Attribution-NonCommercial.

Download (2MB)

Abstract

Grazing can alter plant species interactions in natural rangelands, which in turn might influence the productivity of the ecosystem but we do not fully understand how spatial variability in plant diversity-biomass relationships are modulated by grazing intensity. Here, we hypothesized that plant species co-occurrence in rangelands is mainly driven by niche segregation due to grazing and heterogeneity in local resources, and that grazing, therefore, modulates diversity–biomass relationships. We tested our hypothesis across 35 rangeland sites in Iran, using a species co-occurrence index to assess plant spatial aggregation within each site. At each site, we measured aboveground biomass, plant diversity, topography, soil nutrients, and three levels of grazing intensity. High spatial segregation of plant communities (low species co-occurrence) was found at heavily grazed sites, whereas greater spatial aggregation (high species co-occurrence) was found on low and moderate grazed sites, showing varied associational patterns of species with grazing intensity. Soil nutrients increased with grazing intensity and spatial segregation of plant communities was greater at sites with high soil nutrient concentrations, indicating that grazing intensity influences the spatial heterogeneity of plant communities via nutrients deposited in urine and feces. Declining plant biomass with grazing intensity was related to a strong decline in graminoid species diversity, which suggests that the diversity-biomass relationship is influenced by selective grazing of palatable species. The relationships between species co-occurrence and biomass or plant diversity suggest non-random patterns in species co-occurrences with grazing intensity, which could be the result of competition driven by high livestock grazing intensity. We, therefore, suggest that rangeland stocking rates should be managed properly to maintain rangeland production while promoting plant diversity.

Item Type:
Journal Article
Journal or Publication Title:
Land Degradation and Development
Additional Information:
This is the peer reviewed version of the following article: Sanaei, A., Sayer, E. J., Saiz, H., Yuan, Z., & Ali, A. (2021). Species co-occurrence shapes spatial variability in plant diversity–biomass relationships in natural rangelands under different grazing intensities. Land Degradation & Development, 32( 15), 4390– 4401. doi:10.1002/ldr.4044 which has been published in final form at https://onlinelibrary.wiley.com/doi/10.1002/ldr.4044 This article may be used for non-commercial purposes in accordance With Wiley Terms and Conditions for self-archiving.
Uncontrolled Keywords:
/dk/atira/pure/subjectarea/asjc/1100/1111
Subjects:
ID Code:
157424
Deposited By:
Deposited On:
19 Jul 2021 11:10
Refereed?:
Yes
Published?:
Published
Last Modified:
22 Nov 2022 10:27