Does shrub encroachment reduce foraging grass abundance through plant-plant competition in Lesotho mountain rangelands?

PeerJ

article

Meredith Root-Bernstein¹  Colin Hoag⁴ 

[1] CESCO, CNRS, Musée National d’Histoire Naturelle;Center for Sustainability and Applied Ecology;Institute of Ecology and Biodiversity;Department of Anthropology, Smith College

关键词: Shrub encroachment;    Rangelands;    Plant-plant competition;    Forbs;    Livestock production;    Lesotho;   

DOI  :  10.7717/peerj.13597

学科分类：社会科学、人文和艺术（综合）

来源: Inra

【 摘 要 】

Shrub encroachment is understood to be an important problem facing rangeland ecosystems globally. The phenomenon is still poorly understood both in regard to its impacts (e.g., on diversity, productivity, and soil properties) and its causes. We study the impacts and causes of dwarf shrub encroachment in the highlands of Lesotho. There, shrubs have been described as indicators of generalized land degradation and soil erosion. Surprisingly, our findings show that grass abundance is not reduced by shrub abundance, but that forb abundance does decrease with shrub abundance. We suggest that not enough research has been done to examine the role of forbs in livestock diets, nor in assessing its role in plant-plant competition in grass-shrub systems. Equating shrub presence with declines in available forage may be hasty, as according to our results, grasses were not decreased by shrub expansion in this context; however, forbs are critical components of livestock diets. We propose that the role of forbs in this system should be further studied, focusing on the role that high-nutrient or N-fixing forbs could play in returning nutrients to the soil and affecting livestock grazing patterns, both of which could reduce shrub abundances and favor the establishment of a richer forb community.

【 授权许可】

CC BY