Faculty of Natural Resources & Marine Sciences; Tarbiat Modares University, 46417-76489 Noor, Mazandaran, Iran.
Sci Total Environ. 2022 Dec 20;853:158664. doi: 10.1016/j.scitotenv.2022.158664. Epub 2022 Sep 10.
Vegetation degradation can have significant effects on organic matter fractions as well as various soil characteristics. All these can lead to the changes in soil microbial communities, which are main drivers of nutrient cycles. This is especially important for mountainous ecosystems that are very sensitive and fragile habitats due to their climatic conditions, but less attention has been paid to them. Thus, Mirkola mountainous region (northern Iran) with semi-arid climate and vegetation being dominated by Crataegus and Berberis shrubs were investigated in this study. Sites with different intensities of vegetation degradation [light (60-70 % coverage), moderate (30-40 % coverage) and heavy (0-10 % coverage)] and also non-degraded control sites (90-100 % coverage) were selected. In order to avoid pseudoreplication, three plots, each with an area of 1 ha (100 m × 100 m), were used for each of the four studied habitats. Soil (in three soil depths at 0-10 cm, 10-20 cm and 20-30 cm) samples were collected from the corners and also the center (n = 5) of the plots using iron frames (30 × 30 cm). A total of 180 soil samples (4 habitats × 15 sample × 3 depths) were transferred to the laboratory. Labile and non-labile contents of soil organic matter (SOM) (C and N in soil particles and aggregates, C and N stocks, particulate and dissolved organic matter, hot-water extractable carbohydrate, C and N mineralization) were measured in each of these sites. Results showed that vegetation degradation might result in both labile and non-labile SOM losses. SOM and its associated properties were highest in the non-degraded sites, whereas, lower values were common under degraded areas. Based on the obtained data, vegetation cover can enhance the amount of organic matter entering the soil (especially in the surface layers) and formation of fertile islands in ecosystems. Accordingly, vegetation protection is emphasized to maintain stability and provide ecosystem services in mountainous semi-arid regions.
植被退化会对有机质的各个组分以及各种土壤特性产生显著影响。所有这些都会导致土壤微生物群落的变化，而土壤微生物群落是养分循环的主要驱动因素。这对于山地生态系统来说尤为重要，由于其气候条件，山地生态系统是非常敏感和脆弱的栖息地，但人们对其关注较少。因此，本研究对伊朗北部半干旱气候条件下，以山楂属和小檗属灌木为主的米尔科拉山区进行了研究。选择了不同植被退化强度（轻度[60-70%的覆盖率]、中度[30-40%的覆盖率]和重度[0-10%的覆盖率]）和未退化的对照点（90-100%的覆盖率）。为了避免伪重复，每个研究的四个栖息地都使用了三个面积为 1 公顷（100 m×100 m）的样地。从样地的角落和中心（n=5）用铁框（30×30 cm）采集了 0-10 cm、10-20 cm 和 20-30 cm 三个土壤深度的土壤（共 180 个土壤样品[4 个栖息地×15 个样本×3 个深度]）。将这些土壤样品转移到实验室，测量了土壤有机质（SOM）的可利用和不可利用含量（土壤颗粒和团聚体中的 C 和 N、C 和 N 储量、颗粒态和溶解态有机质、热水可提取碳水化合物、C 和 N 矿化）。结果表明，植被退化可能导致可利用和不可利用的 SOM 损失。未退化的样地中 SOM 及其相关特性的含量最高，而退化样地中的含量则较低。根据获得的数据，植被覆盖可以增加进入土壤的有机物质（特别是在表层土壤）的数量，并在生态系统中形成肥沃的岛屿。因此，强调了保护植被，以保持山区半干旱地区的生态系统稳定性和提供生态系统服务。
