Department of Ecology and Evolutionary Biology, University of Arizona, Tucson, AZ, USA.
Department of Environmental Science and Technology, University of Maryland, 1428 Anim. Sci/Agr. Eng Bldg., College Park, MD, 20742-2315, USA.
Sci Rep. 2022 Apr 6;12(1):5794. doi: 10.1038/s41598-022-09769-7.
Biological soil crusts (BSC) are important contributors to nutrient cycling in arid environments such as the Sonoran Desert. BSC at an urban (University Indian Ruins) and at a non-urban site (Santa Rita Experimental Range) were compared to determine if their structure or function was influenced by proximity to an urban environment. The Step Point method was used in the field to determine ground cover; which was found to be similar between sites. However, the spatial distribution of the BSCs was significantly different, such that more BSCs were found under plants at the non-urban site (P < 0.05). Relative gross photosynthesis was measured in the lab by addition of a watering event. Gross photosynthesis was found to be higher in the non-urban BSCs (P < 0.001), indicating lowered productivity in urban BSCs due to effects caused by proximity to urban environments. This study provides evidence that BSCs at urbanized sites are affected functionally, and therefore may be contributing differently to carbon and nitrogen cycling in these ecosystems.
生物土壤结皮（BSC）是干旱环境（如索诺兰沙漠）养分循环的重要贡献者。对城市（印第安遗址大学）和非城市（圣丽塔实验牧场）的 BSC 进行了比较，以确定它们的结构或功能是否受到接近城市环境的影响。现场采用步点法确定地表覆盖度；结果发现，两个地点的地表覆盖度相似。然而，BSC 的空间分布有显著差异，即在非城市地点，更多的 BSC 出现在植物下（P<0.05）。相对总光合作用在实验室通过加水事件进行测量。结果发现，非城市 BSC 的总光合作用更高（P<0.001），这表明由于接近城市环境的影响，城市 BSC 的生产力降低。本研究提供的证据表明，城市化地区的 BSC 在功能上受到影响，因此可能对这些生态系统的碳氮循环产生不同的影响。
