Subjects: Biology >> Botany >> Applied botany submitted time 2024-02-07 Cooperative journals: 《广西植物》
ZHANG Yong
MA Yandan
ZHENG Qiuzhu
SU Derong
DONG Shikui
LIANG Kemin
WU Kaiting
YUE Haitao
WANG Xiaorong
Abstract： This study aimed to investigate the effects of environmental disturbances on the stoichiometry characteristics of plants in degraded alpine meadows. To achieve this, a mowing experiment was conducted on an alpine meadow with three degradation levels (i.e., light degradation LD, moderate degradation MD, and severe degradation SD) in Shangri-La from 2018 to 2020. Subsequently, differences in plant carbon (C) content, nitrogen (N) content, phosphorous (P) content, C:N:P ratio, and N-P power function relationship among different mowing durations (i.e., 0 a, 1 a, and 2 a, respectively) were analysed. The results were as follows: (1) Except for the P content of Cyperaceae, plant C, N and P of the entire community, Gramineae and forbs did not vary among degradation levels (P > 0.05) during the mowing experiment. Plant C, N and P tended to increase and then decrease with increasing mowing years, i.e., these indices were the highest after 1 a of mowing (P < 0.05). (2) At the community and functional group levels, there was no significant difference in plant C:N ratio and C:P ratio among degradation levels (P > 0.05). From LD to SD, the N:P ratio of the plant community, Cyperaceae and forbs tended to increase (P < 0.05), while the N:P ratio of Gramineae did not change significantly (P > 0.05). (3) The N:P ratio showed a parabolic trend, while the C:N ratio and C:P ratio showed an inverse trend with increasing mowing duration. Before mowing (i.e., mowing 0 a), the C:P ratio and N:P ratio of Cyperaceae were higher than those of forbs (P < 0.05) but did not vary from those of the plant community and Gramineae (P > 0.05). After mowing (i.e., mowing 1 a or 2 a), the C:P ratio and N:P ratio of Cyperaceae were higher than those of the whole plant community, Gramineae, and forbs (P < 0.05). At each mowing duration, the C:N ratio of plants did not vary among plant communities and functional groups (P > 0.05). (4) Mowing caused a stronger N-P power function relationship and a stable power exponent both at the plant community and functional group levels. And the N-P power exponent of Cyperaceae was less than 0.1, while that of the plant community, Gramineae and forbs remained stable at 0.19-0.22. In conclusion, this study found that plant stoichiometry remained stable across degradation levels but changed significantly with the prolongation of the mowing duration. This implies that different degraded alpine meadows in Northwestern Yunnan Province may share common response mechanisms to mowing disturbance.
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