Avaliação da recuperação de serviços de polinização e diversidade funcional de atributos florais de áreas em restauração: uma comparação entre sistemas de restauração ativa e sistemas agroflorestais

Abstract

Ecological restoration is the process that initiates or accelerates the restoration of an ecosystem that has been degraded. Biodiversity is closely linked to the ecosystem functioning, and there is a positive relationship between biodiversity and the improvement of ecosystem services. The main goal was to investigate and compare the effect of different ecological restoration systems (i.e., agroforestry systems - AFS - and active restoration systems with planting of native species - RES) on the availability of resources for the fauna (flowers/fruits) and the magnitude of difference or similarity in terms of ecosystem functionality, considering areas in their natural state (REF) as reference forests. For this, I used bee-plant networks interactions as an ecological indicator of restoration. I tested the following hypotheses: 1. Reference ecosystems have more zoochoric species and greater diversification of functional groups - floral types (Chapter 1). 2. Agroforestry systems can be self-sustaining, approaching or matching the degree of resistance and resilience of their reference ecosystem (Chapter 1). 3. Areas under restoration contain a characteristic subset of species that occur in the reference ecosystem, and exhibit robust mutualistic interactions, providing an appropriate community structure (Chapter 2). 4. There will be functional redundancy in the areas under restoration when compared to the reference ecosystem and consequent similarity in the structural patterns of the interaction networks among the areas (Chapter 2). I used three areas for each system (REF, RES and AFS) located in the municipalities of Ivinhema, Jateí, Caarapó and Dourados, State of Mato Grosso do Sul, Brazil. Furthermore, through a systematic review, I discussed the potential of AFS to restore pollination services and contribute to the maintenance of pollinator diversity and abundance both in these areas and in adjacent matrices (Chapter 3). The first hypothesis was partially rejected. I found significant differences among the areas when I compared the size and color of the flowers to characterize the functional groups, however I did not observe any difference in the pattern of occurrence of the dispersion syndromes or floral type. I didn’t find evidence to reject the second hypothesis, considering the high availability of flowers and fruits throughout the year, in addition to the considerable diversity of floral types found in the AFS. Ecological restoration through AFS can have excellent results, as long as the interventions are handled with caution, without invasive species and with preferential use of native food plants. Bee-plant ecological networks proved to be excellent indicators for monitoring the success of ecological restoration. The AFS were similar to the reference ecosystems in terms of species diversity and interactions between bee-plant pairs, in addition to presenting considerable nestedness. Therefore, hypotheses 3 and 4 were supported. However, it should be pointed out that in the active restoration areas, the interactions were less robust, although it appears that these communities are on the way to complete restoration, since they showed a high diversity of bee species and a nested network structure. The systematic review revealed a growing scientific production on the subject in the last two decades. Contrarily to conventional restoration systems, AFS have shown great profit potential over restoration. However, ecological restoration through AFS still remains poorly understood, requiring studies of biological aspects of these systems in addition to socioeconomic approaches at different scales so that AFS are designed in a way that fit the various objectives, especially sustainable food production.