Churchill Amber C, Faist Akasha M
Department of Ecology, Evolution and Behavior, University of Minnesota, St. Paul, MN 55108, USA.
Department of Animal and Range Sciences, New Mexico State University, Las Cruces, NM 88003, USA.
AoB Plants. 2021 Jul 5;13(6):plab042. doi: 10.1093/aobpla/plab042. eCollection 2021 Dec.
Given the frequent overlap between biological plant invasion and ecological restoration efforts it is important to investigate their interactions to sustain desirable plant communities and modify long-term legacies both above- and below-ground. To address this relationship, we used natural reference, invaded and created vernal pools in the Central Valley of California to examine potential changes in direct and indirect plant effects on soils associated with biological invasion and active restoration ecosystem disturbances. Our results showed that through a shift in vegetation composition and changes in the plant community tissue chemistry, invasion by non-native plant species has the potential to transform plant inputs to soils in vernal pool systems. In particular, we found that while invasive plant litter decomposition was driven by seasonal and interannual variability, associated with changes in precipitation, the overall decomposition rates for invasive litter was drastically lower than native species. This shift has important implications for long-term alterations in plant-based inputs to soils in an amplifying feedback to nutrient cycling. Moreover, these results were independent of historic active restoration efforts. Despite the consistent shift in plant litter decomposition rates and community composition, we did not detect associated shifts in below-ground function associated with invasion by non-native plants. Instead, soil C:N ratios and microbial biomass did not differ between invaded and naturally occurring reference pools but were reduced in the manipulated created pools independent of invasion levels. Our results suggest that while there is an observed invasive amplifying feedback above-ground this trajectory is not represented below-ground, and restoration legacies dominated 10 years after practices were applied. Restoration practices that limit invasive plant feedbacks and account for soil legacy recovery, therefore offer the best solution for disturbed ephemeral ecosystems.
鉴于生物性植物入侵与生态恢复工作之间经常存在重叠，研究它们之间的相互作用对于维持理想的植物群落以及改变地上和地下的长期遗留影响至关重要。为了探究这种关系，我们利用加利福尼亚中央谷地的天然参照池、受入侵池和人工建造的春池，来研究生物入侵和主动恢复生态系统干扰相关的植物对土壤直接和间接影响的潜在变化。我们的结果表明，通过植被组成的转变和植物群落组织化学的变化，非本地植物物种的入侵有可能改变春池系统中植物对土壤的输入。具体而言，我们发现虽然入侵植物凋落物的分解受季节和年际变化驱动，与降水变化相关，但入侵凋落物的总体分解速率远低于本地物种。这种转变对植物向土壤的输入的长期变化具有重要意义，在对养分循环的放大反馈中。此外，这些结果与历史上的主动恢复工作无关。尽管植物凋落物分解速率和群落组成持续变化，但我们未检测到与非本地植物入侵相关的地下功能变化。相反，入侵池和天然参照池之间的土壤碳氮比和微生物生物量没有差异，但在人工建造的池中，无论入侵水平如何，这些指标都有所降低。我们的结果表明，虽然在地上观察到入侵的放大反馈，但这种轨迹在地下并未体现，并且在实施恢复措施10年后，恢复遗留影响占主导。因此，限制入侵植物反馈并考虑土壤遗留恢复的恢复措施，为受干扰的临时生态系统提供了最佳解决方案。
