Linking soil biodiversity and ecosystem function in a Neotropical savanna

Abstract

Conserving the remaining savanna ecosystems in the Brazilian savanna (Cerrado) -a global biodiversity hotspot that stores carbon and provides water to a large portion of South Americarequires understanding the ecological processes maintaining their function. Nutrient cycling supports savanna function via plant litter production and decomposition by soil fauna, releasing nutrients for plant and soil organism uptake. Soil biodiversity and biogeochemistry linkages with litter dynamics in Neotropical savannas under a changing climate are poorly understood. Here, we combined two years of rainfall seasonality, leaf and wood litter production and decomposition with soil epigeic fauna abundancethe number of ground-surface dwelling invertebrates collected through pitfall trapstaxa richness, Shannon's diversity and Pielou's evenness, and 16 soil biogeochemical variables measured in 12 plots of preserved savanna. Rainfall seasonality modulated the mean soil epigeic fauna diversity and evenness across all plots, which were highest in the rainy season, in contrast to litterfall rates, which peaked in the dry season. In the dry season (April to September), the Formicidae family was the most abundant with 50% of all individuals, while in the rainy season (October to March), the Isoptera order was the most abundant with approximately 39% of individuals. Wood litter decomposition grouped with annual Hemiptera abundance, covarying with soil epigeic fauna diversity and evenness per plot and against soil fertility variables. Leaf litter decomposition co-varied with the total epigeic fauna abundance and soil pH. We speculate that the specific need to decompose wood litter may be associated with a greater need for diversity than an abundance of soil epigeic fauna. Our work highlights the role of rainfall seasonality on soil biodiversity and physicochemistry, which is also tightly linked with litter production and decomposition. This study advances our understanding of the mechanisms governing nutrient cycling in savanna ecosystems on nutrient-impoverished soils, with implications for achieving sustainable conservation and restoration goals.

Mixed Forest of Larix principis-rupprechtii and Betula platyphylla Modulating Soil Fauna Diversity and Improving Faunal Effect on Litter Decomposition

“…The diversity index of soil fauna can reflect the complexity of community composition and reveal the response characteristics of the soil fauna community to environmental changes [43]. In this study, the Shannon-Wiener index (H) in the MF was higher than in the LF, consistent with the higher soil fauna diversity in other mixed forest areas [44][45][46].…”

Response of Soil Nematode Community Structure and Function to Monocultures of Pumpkin and Melon

“…Soil biodiversity is an indicator of soil health, and the H was positively correlated with soil nutrients, suggesting that soil nematode diversity could be associated with soil nutrient cycling. There is speculation that the decomposition of wood litter may be more associated with diversity than the abundance of soil epigeic fauna [54], and some studies have proven that soil biodiversity is very important for maintaining soil fertility [55]. The relationship between food web indices (EI, SI, and CI) and soil properties indicates that higher nutritionrich soil increases the available soil resources of soil nematodes and promotes the structure and trophic links of the soil food web, thereby resulting in a more bacterial-dominated decomposition pathway.…”

Ants (Hymenoptera: Formicidae) of the Parque Estadual São Camilo, an isolated Atlantic Forest remnant in western Paraná, Brazil

“…This forest type was once considered one of the richest in Brazil in terms of wood volume per unit of area due to a fertile soil derived from basalt (IAT 2022b). Also, the high humidity and wide range substrates for nesting and forage as mold, leaf litter and well-developed roots provide conditions that favor the establishment of ant colonies (Inkotte et al 2022). Ants in these environments are more prone to be captured with Winkler extractors, which could explain the higher number of exclusive species obtained with this technique in our study.…”