Sustainable management of the native mixed forest: aerial and belowground interactions between plants and insects

Abstract

The loss of native forests and the services that these provide is a problem of great relevance in Argentina and worldwide. Such loss is partly due to the lack of technologies that allow producers to use the forest sustainably, both in economic and environmental terms. In Río Negro, the native mixed forest, one of the most diverse in the region (also known as tall shrubland), has been historically replaced by livestock systems or by afforestation with exotic species. In three mixed forests of Río Negro, we are evaluating the relationship between economic profitability and the environmental impact of 8 management practices. These practices result from a factorial design at the plot level (1418 m2 each), which includes 4 harvesting intensities crossed with plantation of native tree species (plots with or without plantation). At the transect level within the plot, we planted 3 origins of each of 6 native tree species (one species per transect). These practices prioritize different forest products, such as firewood and non-wood products in the unplanted plots vs. timber in the planted plots, and we expect them to have different environmental and economic impacts. We are evaluating the response of quantitative plant-insect interaction networks, both aerial and belowground, focusing on plant-pollinator interactions, plant-leaf herbivores and plant- root herbivores. Insects are an important component of the biodiversity of Patagonian forests, which in turn can have an impact on forest productivity and timber quality as well as on non-wood products. We will evaluate leaf quality for herbivores and physical-chemical characteristics of soils that impact both plants and insects. We will relate the impact of practices on quantitative networks of plant-insect interaction with aspects of economic profitability (e.g. product quality, target market and price). From the point of view of the implementation of local and regional policies, we will provide information lacking on management technologies, economic profitability and environmental impact that will contribute to the adequate implementation of the Law 26,331 of Minimum Budgets for the Protection of Native Forests. For example, our results will contribute to the allocation of economic incentives to producers by Law 26,331 according to the economic profitability and the environmental impact of the practices proposed in their management plans. From the global and conceptual point of view, our results will be novel contributions on less explored aspects of agricultural and forestry theory, such as the simultaneous interaction of a diverse group of plants and insects and their consequences on the belowground and aerial processes.