Grazing intensity alters the plant diversity‐ecosystem carbon storage relationship in rangelands across topographic and climatic gradients

Sanaei, Anvar and Sayer, Emma J. and Yuan, Zuoqiang and Saiz, Hugo and Delgado‐Baquerizo, Manuel and Sadeghinia, Majid and Ashouri, Parvaneh and Ghafari, Sahar and Kaboli, Hasan and Kargar, Mansoureh and Seabloom, Eric W. and Ali, Arshad (2023) Grazing intensity alters the plant diversity‐ecosystem carbon storage relationship in rangelands across topographic and climatic gradients. Functional Ecology. ISSN 0269-8463 (In Press)

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Abstract

1. Plant diversity supports multiple ecosystem functions, including carbon sequestration. Recent shifts in plant diversity in rangelands due to increased grazing pressure and climate changes have the potential to impact the sequestration of carbon in arid to semi-humid regions worldwide. However, plant diversity, grazing intensity and carbon storage are also influenced by environmental factors such as nutrient availability, climate, and topography. The complexity of these interactions limits our ability to fully assess the impacts of grazing on biodiversity-ecosystem function (BEF) relationships. Read the free Plain Language Summary for this article on the Journal blog. 2. We assessed how grazing intensity modifies BEF relationships by determining the links between plant diversity and ecosystem carbon stocks (plant and soil carbon) across broad environmental gradients and different plant growth forms. To achieve this, we surveyed 1493 quadrats across 10 rangelands, covering an area of 23,756 ha in northern Iran. 3. We show that aboveground carbon stocks increased with plant diversity across topographic, climatic and soil fertility gradients. The relationship between aboveground carbon stocks and plant diversity was strongest for forbs, followed by shrubs and grasses. Soil carbon stocks increased strongly with soil fertility across sites, but aridity, grazing, plant diversity and topography were also important in explaining variation in soil carbon stocks. 4. Importantly, aboveground and soil carbon stocks declined at high grazing intensity, and grazing modified the relationship between plant diversity and carbon stocks regardless of differences in abiotic conditions across sites. 4. Our study demonstrates that relationships between plant diversity and ecosystem carbon stocks persist across gradients of aridity, topography, and soil fertility, but the relationships are modified by grazing intensity. Our findings suggest that potential losses in plant diversity under grazing intensification could reduce ecosystem carbon storage across wide areas of arid to semi-humid rangelands. We discuss the potential mechanisms underpinning rangeland BEF relationships to stimulate future research.

Item Type:
Journal Article
Journal or Publication Title:
Functional Ecology
Uncontrolled Keywords:
/dk/atira/pure/subjectarea/asjc/1100/1105
Subjects:
ID Code:
184865
Deposited By:
Deposited On:
25 Jan 2023 11:35
Refereed?:
Yes
Published?:
In Press
Last Modified:
25 Jan 2023 11:35