Lhasa Plateau Ecosystem Research Station, Key Laboratory of Ecosystem Network Observation and Modelling, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing 100101, China; University of Chinese Academy of Sciences, Beijing 100049, China.
Lhasa Plateau Ecosystem Research Station, Key Laboratory of Ecosystem Network Observation and Modelling, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing 100101, China; Freie Universität Berlin, Institute of Biology, Biodiversity/Theoretical Ecology, Altensteinstraße 34, 14195 Berlin, Germany.
J Environ Manage. 2019 May 15;238:352-359. doi: 10.1016/j.jenvman.2019.03.010. Epub 2019 Mar 8.
Forage-livestock balance is important for sustainable management of alpine grasslands under global change, but the robustness of diverse algorithms for assessing forage-livestock balance is still unclear. This study compiled long-term (2009-2014) field observations of aboveground biomass (AGB). Using climate and remote sensing data, we evaluated the inter-annual dynamics of the forage-livestock balance on the Northern Tibetan Plateau (NTP). Here, we assumed that AGB dynamics in fenced grasslands (AGB) is only driven by climate change; whereas AGB dynamics in open grasslands grazed by livestock (AGB) is driven by a combination of climate change and human activities. Thus, human-induced change in AGB (AGB) could be estimated via the difference between AGB and AGB. Furthermore, differences in the temporal trends between AGB and AGB could indicate the state of forage-livestock balance, overgrazed or not, in alpine grasslands. Our results showed that the overall status of the forage-livestock balance from 2000 to 2006 was overgrazed owing to poor climatic conditions. Ecological projects and economic policies for alpine grassland conservation had not been implemented at that time, which also resulted in local overgrazing. From 2006 to 2014, the alpine grasslands in some areas were in a less-grazed state. We suggest that the livestock number could potentially increase in northern NTP and should be reduced or strictly controlled to maintain the balance between livestock and forage in the southern and southeast areas. In conclusion, the results of this study suggest that the evaluation of the forage-livestock balance in the NTP should include the local climatic conditions and make better use of grassland resources while ensuring ecological security.
在全球变化下，饲草-家畜平衡对于高山草地的可持续管理至关重要，但评估饲草-家畜平衡的各种算法的稳健性仍不清楚。本研究汇编了长期（2009-2014 年）地上生物量（AGB）的野外观测。利用气候和遥感数据，我们评估了青藏高原北部（NTP）饲草-家畜平衡的年际动态。在这里，我们假设围栏草地（AGB）的 AGB 动态仅受气候变化驱动；而牲畜放牧的开放草地（AGB）的 AGB 动态则受到气候变化和人类活动的共同驱动。因此，可以通过 AGB 与 AGB 的差异来估计 AGB 的人为变化。此外，AGB 和 AGB 之间时间趋势的差异可以指示高山草地的饲草-家畜平衡状况，即是否过牧。我们的研究结果表明，由于气候条件较差，2000 年至 2006 年的饲草-家畜平衡总体状况处于过牧状态。当时，针对高山草地的生态保护项目和经济政策尚未实施，这也导致了局部过牧。2006 年至 2014 年，部分地区的高山草地处于放牧较轻的状态。我们建议，在 NTP 的北部地区，牲畜数量可能会增加，为了保持南部和东南部地区的家畜与饲草之间的平衡，应该减少或严格控制牲畜数量。总之，本研究结果表明，在 NTP 评估饲草-家畜平衡时，应考虑当地的气候条件，在确保生态安全的同时更好地利用草地资源。
