College of Resources and Environmental Engineering, Tianshui Normal University, Tianshui, 741001, Gansu, China; Gansu Key Laboratory of Utilization of Agricultural Solid Waste Resources, Tianshui Normal University, Tianshui, 741001, Gansu, China.
Gansu Key Laboratory of Utilization of Agricultural Solid Waste Resources, Tianshui Normal University, Tianshui, 741001, Gansu, China.
J Environ Manage. 2024 Jun;361:121239. doi: 10.1016/j.jenvman.2024.121239. Epub 2024 May 29.
The roles of plateau pika (Ochotona coronae) in the Tibetan Plateau are often controversial, because it is often regarded as a destructive pest or an ecosystem engineer. Here a meta-analysis using 72 paired observations was conducted to examine whether the impacts of plateau pika on environmental quality (i.e., plant and soil properties) depend on population density in the Tibetan Plateau. Pika population density was used as a proxy for disturbance intensity. The pika disturbance intensity was divided into five groups based on the number of burrows, including low disturbance intensity (LD) (9-30 burrows per ha), medium disturbance intensity (MD) (31-100 burrows per ha), high disturbance intensity (HD) (101-170 burrows per ha), extreme disturbance intensity (ED) (171-240 burrows per ha) and uncontrolled (or excessive) disturbance intensity (UD) (>241 burrows per ha). Given that sample sizes in some of the groups are small (especially for the HD), we further pooled the disturbance groups including the LD-MD and HD-UD. Overall, relative to control (i.e., no disturbing), there was a great increase (80.3%) in aboveground biomass under the LD-MD, whereas a decrease of 41.1% occurred under the HD-UD. At the same time, plant coverage, species richness, height, and belowground biomass greatly decreased only in the HD-UD. Furthermore, the effect size of plant coverage, species richness, and aboveground biomass also declined with pika burrow density significantly. With regard to soil properties, there was a significant increase in soil organic carbon, ammonium nitrogen, and soil organic carbon stock under the LD-MD, whereas a decrease under the HD-UD. In addition, soil total nitrogen, total potassium, and nitrate nitrogen increased at the LD-MD and HD-UD. Nevertheless, the effect size of these soil properties (with >20 observations) was not related to pika burrow density. In summary, there is an implication that the low and moderate disturbance of pikas is beneficial to maintain and promote ecosystem functioning in the Tibetan grasslands. In the future pikas' eradication policy should be reconsidered in alpine grassland management.
高原鼠兔在青藏高原上的作用常常存在争议，因为它通常被视为一种破坏性害虫或生态系统工程师。在这里，我们使用 72 对观测数据进行了荟萃分析，以检验高原鼠兔对环境质量（即植物和土壤特性）的影响是否取决于高原鼠兔的种群密度。鼠兔种群密度被用作干扰强度的替代指标。根据洞穴数量，将鼠兔干扰强度分为 5 组，包括低干扰强度（LD）（每公顷 9-30 个洞穴）、中干扰强度（MD）（每公顷 31-100 个洞穴）、高干扰强度（HD）（每公顷 101-170 个洞穴）、极高干扰强度（ED）（每公顷 171-240 个洞穴）和失控（或过度）干扰强度（UD）（每公顷>241 个洞穴）。鉴于一些组的样本量较小（尤其是 HD），我们进一步将 LD-MD 和 HD-UD 这两个干扰组进行了合并。总的来说，与对照（即无干扰）相比，LD-MD 下地上生物量增加了 80.3%，而 HD-UD 下则减少了 41.1%。同时，只有在 HD-UD 下，植物覆盖率、物种丰富度、高度和地下生物量才会大幅下降。此外，植物覆盖率、物种丰富度和地上生物量的效应大小也随鼠兔洞穴密度的显著下降而显著下降。至于土壤性质，LD-MD 下土壤有机碳、铵态氮和土壤有机碳储量显著增加，而在 HD-UD 下则减少。此外，LD-MD 和 HD-UD 下土壤全氮、全钾和硝态氮增加。然而，这些土壤性质（有>20 个观测值）的效应大小与鼠兔洞穴密度无关。总之，这表明低强度和中强度的鼠兔干扰有利于维持和促进青藏高原草地的生态系统功能。在未来的高山草原管理中，应该重新考虑对鼠兔的根除政策。
