Macro and mesofauna soil food webs in two temperate grasslands: responses to forestation with Eucalyptus

María Leticia Sabatté; Marcelo Juan Massobrio; Mariano Tomás Cassani; Fernando Roberto Momo

doi:10.1016/j.heliyon.2020.e05869

Macro and mesofauna soil food webs in two temperate grasslands: responses to forestation with Eucalyptus

Heliyon. 2021 Jan 6;7(1):e05869. doi: 10.1016/j.heliyon.2020.e05869. eCollection 2021 Jan.

Authors

María Leticia Sabatté^{1

2}, Marcelo Juan Massobrio², Mariano Tomás Cassani², Fernando Roberto Momo³

Affiliations

¹ Universidad Nacional de Luján, Laboratorio de Ecología, Rutas 5 y 7, B6700ZAB, Luján, Argentina.
² Cátedra de Manejo y Conservación de Suelos. Facultad de Agronomía, Universidad de Buenos Aires, Av. San Martín 4453 C1417DSE, Buenos Aires, Argentina.
³ Instituto de Ciencias, Universidad Nacional de General Sarmiento, Juan M. Gutiérrez 1150, B1613GSX, Los Polvorines, Argentina.

Abstract

We studied the effects of land use change from grassland to Eucalyptus 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 Eucalyptus 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 Eucalyptus plantations and 20-year-old Eucalyptus 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 Eucalyptus 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.

Keywords: Biodiversity; Detrital food webs; Disturbance; Land use; Soil fauna; Trophic species.