Sabatté María Leticia, Massobrio Marcelo Juan, Cassani Mariano Tomás, Momo Fernando Roberto
Universidad Nacional de Luján, Laboratorio de Ecología, Rutas 5 y 7, B6700ZAB, Luján, Argentina.
Cátedra de Manejo y Conservación de Suelos. Facultad de Agronomía, Universidad de Buenos Aires, Av. San Martín 4453 C1417DSE, Buenos Aires, Argentina.
Heliyon. 2021 Jan 6;7(1):e05869. doi: 10.1016/j.heliyon.2020.e05869. eCollection 2021 Jan.
We studied the effects of land use change from grassland to spp. plantation on macro and mesofauna soil food webs in two sites in the Rolling Pampas. We expected to find differences in the parameters that characterize the structure of soil food webs, as the implantation of implies changes in the characteristics of the resources and the microhabitat conditions. We also expected to find differences in the communities in terms of diversity, abundance, and species present. The treatments were: grasslands; 10-year-old plantations and 20-year-old plantations. Seasonal samplings were performed for the extraction of soil fauna in winter, spring, summer and autumn. For the analysis of food webs, we worked with "trophic species'': groups of organisms that have the same prey and the same predators. A total of 25 food webs were laid out using bibliographical information of feeding habits from the identified taxa. From each food web, we obtained a predator overlap graph, in which the consumers that share the same source or prey are linked by an arrow. In addition, the Shannon-Wiener index was calculated. We found that trophic species densities were different among the treatments: communities from grassland and the younger plantations were dominated by earthworms and other secondary decomposers, while the community in the older plantation showed a greater contribution of primary decomposers (Shymphyla, Isopoda and Diplopoda). No significant differences between treatments were found in the parameters that characterize the structure of soil food webs, i.e. connections number, number of trophic species nor connectivity. However, the diversity of the community was lower in the youngest plantations than in the other treatments, and it shows evidence of compartmentalization in the predator overlap graphs. Our findings suggest that the meso and macrofauna communities in the 10-years-old plantations represent a transition between the communities from grasslands and the oldest plantations. We conclude that the effects of forestation with on soil fauna communities are evident through changes in functional groups rather than changes in the parameters that characterize the structure of soil food webs.
我们研究了潘帕斯草原地区两个地点从草地转变为特定树种种植园的土地利用变化对大型和中型土壤动物食物网的影响。我们预计会发现表征土壤食物网结构的参数存在差异，因为特定树种的种植意味着资源特征和微生境条件的变化。我们还预计在群落的多样性、丰度和现存物种方面会发现差异。处理方式包括：草地；10年树龄的特定树种种植园和20年树龄的特定树种种植园。在冬季、春季、夏季和秋季进行季节性采样以提取土壤动物。为了分析食物网，我们使用了“营养物种”：具有相同猎物和相同捕食者的生物群体。利用已鉴定分类单元的摄食习性的文献信息，共构建了25个食物网。从每个食物网中，我们获得了一个捕食者重叠图，其中共享相同食物来源或猎物的消费者通过箭头相连。此外，还计算了香农 - 维纳指数。我们发现不同处理方式下营养物种密度存在差异：草地和较年轻种植园的群落以蚯蚓和其他二级分解者为主，而较老种植园的群落中初级分解者（弹尾目、等足目和倍足纲）的贡献更大。在表征土壤食物网结构的参数方面，即连接数、营养物种数量和连通性，各处理之间未发现显著差异。然而，最年轻种植园的群落多样性低于其他处理方式，并在捕食者重叠图中显示出分隔的迹象。我们的研究结果表明，10年树龄种植园中的中型和大型土壤动物群落代表了草地群落和最老种植园群落之间的过渡。我们得出结论，特定树种造林对土壤动物群落的影响通过功能组的变化而非表征土壤食物网结构的参数变化而明显体现。
