Heavy grazing causes plant cluster fragmentation of sparse grasses

Zihan Wang; Shijie Lv; Hongmei Liu; Chen Chen; Zhiguo Li; Zhongwu Wang; Guodong Han

doi:10.1002/ece3.10581

Heavy grazing causes plant cluster fragmentation of sparse grasses

Ecol Evol. 2023 Oct 5;13(10):e10581. doi: 10.1002/ece3.10581. eCollection 2023 Oct.

Authors

Zihan Wang¹, Shijie Lv², Hongmei Liu³, Chen Chen¹, Zhiguo Li¹, Zhongwu Wang¹, Guodong Han¹

Affiliations

¹ College of Grassland, Resources and Environment Inner Mongolia Agricultural University Hohhot Inner Mongolia China.
² Science College Inner Mongolia Agricultural University Hohhot Inner Mongolia China.
³ Forestry Research Institute of Inner Mongolia Autonomous Region Hohhot Inner Mongolia China.

Abstract

Cleistogenes songorica, as a clustered grass, is the main grassland flora of the Stipa breviflora desert grassland. Some studies have shown that the constructive species of S. breviflora (sparse cluster type) is prone to cluster fragmentation; however, research on C. songorica is relatively rare. Then will the C. songorica plant population (dense cluster type) also have cluster fragmentation under the influence of intense grazing? To answer this question, we used variance analysis and geo-statistical methods. The spatial distribution of C. songorica in S. breviflora desert steppe in Inner Mongolia was measured under four grazing intensities (no grazing, CK, 0 sheep·ha^-1·half year^-1; light grazing, LG, 0.93 sheep·ha^-1·half year^-1; moderate grazing, MG, 1.82 sheep·ha^-1·half year^-1; and heavy grazing, HG, 2.71 sheep·ha^-1·half year^-1) and four scales (10 cm × 10 cm, 20 cm × 20 cm, 25 cm × 25 cm, 50 cm × 50 cm). We then analyzed C. songorica whether fragmentation was present. The results showed that increased grazing intensity is associated with increased density and decreased height, coverage, and standing crop of C. songorica. The spatial distribution of C. songorica was affected by structural factors, and spatial heterogeneity decreased with increased spatial scale. With increased grazing intensity and spatial scale, the patch area of C. songorica gradually increased and tended toward band distribution. In summary, increased grazing intensity and spatial scale led to weakened heterogeneity of C. songorica spatial distribution and increased consistency.

Keywords: different scales; geo‐statistics; plant cluster fragmentation.