Microhabitat heterogeneity promotes soil fertility and ground-dwelling arthropod diversity in Mediterranean wood-pastures

Abstract

Mediterranean wood-pastures are extensive agroforestry systems that hold great ecological, social and cultural values, which consist of mixtures of grassland, scattered trees and shrubs, primarily used for livestock grazing. For centuries, low-intensity management in these landscapes has resulted in multiple microhabitats that favour biodiversity and are considered key elements for the long-term persistence of wood-pastures. However, the relative contribution of each microhabitat type to wood-pasture biodiversity and functioning remains poorly studied. We investigated the impact that different wood-pasture microhabitats have on soil chemical fertility and the decomposition food web. We analysed the two main microhabitats that make wood-pastures upopen grasslands and isolated Treesand three additional "litter-trapping" microhabitatsshrubs scattered in the grassland matrix, canopied shrubs and piles of pruning debris-in terms of soil chemical properties (organic matter content, total N, C:N ratio, available P, and exchangeable base cations), collembolan and dipteran (mostly detritivores) abundance, and carabid (seed-eaters and predators) and staphylinid (mostly predators) beetle abundance, body size, biomass, species richness and composition. Grasslands were the most different microhabitats, with the lowest soil nutrient content and particular carabid and staphylinid species composition. Trees had the highest soil fertility levels and abundance of Diptera and staphylinids, and held unique staphylinid assemblages. "Litter-trapping" microhabitats had medium to high soil nutrient values and shared a distinct staphylinid assemblage compared to grasslands and trees. Besides, scattered shrubs provided shelter for large-sized carabid and staphylinid predators, while canopied shrubs held the highest carabid abundance and biomass. "Litter-trapping" microhabitats retained tree leaves that would otherwise be lost to the wood-pasture, recovering nutrients to the system, and provided new habitat, shelter and food for detritivores and unique predator assemblages. "Litter-trapping" microhabitats thus enhanced soil fertility and the decomposition process, at the same time as increased the abundance and diversity of the communities of ground-dwelling detritivores and predators inhabiting wood-pastures. These findings confirmed that microhabitat heterogeneity resulting from low-intensity management is essential to maintain both the primary production and the biodiversity conservation value of wood-pastures.

Sparse trees and shrubs confers a high biodiversity to pastures: Case study on spiders from Transylvania

“…Sparse woody vegetation is of crucial importance for the overall biodiversity of pastures [ 7 ], [ 8 ], [ 11 ], [ 12 ] ( Table 4 ) and contributes to the soil fertility [ 14 ]. Still, this vegetation elements are not explicitly recognized by major policies and institutions responsible for the governance of the management of the pastoral systems [ 18 ].…”

“…Solitary trees on pastures significantly increased the overall diversity of lichens [ 9 ], vascular plants and bryophytes [ 10 ]. Sparse trees are important breeding sites for birds [ 11 ], [ 12 ] and they may also harbor a great invertebrate diversity [ 13 ], [ 14 ]. Trees create a distinct microclimatic conditions on grasslands and this results in distinct arthropod species assemblages, including several rare species [ 15 ], [ 16 ], [ 17 ].…”

Vegetation Heterogeneity Effects on Soil Macro-Arthropods in an Alpine Tundra of the Changbai Mountains, China

“…At the same time, we observed that vegetation heterogeneity can indirectly affect the soil macro-arthropod communities by altering the soil fertility and soil texture. García-Tejero and Taboada have shown that vegetation heterogeneity enhanced the soil fertility and the decomposition process, and increased the contents of available nutrients [34]. A large amount of available nutrients could potentially promote plant growth, as well as supply sufficient food, and thus enhance the abundance, richness and diversity of soil macro-arthropods.…”

Which Factors Favour Biodiversity in Iberian Dehesas?

“…The presence of trees on open grasslands is also a positive factor for diversity in ants [43,44], coleoptera and diptera [45][46][47][48][49]. Ant species richness and Shannon diversity tend to increase in areas under Q. rotundifolia canopies as a consequence of the shade effect, as tree size plays an important role in the density of ground ant nests.…”