Intervention ecology with fire uses to maintain the availability of flowers and fruits for fauna in tropical wetlands

Abstract

Fire is an ecological disturbance acting as one of the major environmental filters shaping the structure and functioning of open grassy vegetation. Likewise, water selects for species tolerant to certain environmental conditions, such as soil moisture saturation and flooding, filters species tolerant to each environmental condition. In the Pantanal, for example, flooding is one of the main factors responsible for shaping vegetational heterogeneity. Therefore, as the Pantanal is a seasonal biome with high primary productivity, different fire regimes, considering frequency and period of burning, help shape the heterogeneity of its landscapes. The interaction between different fire and flood regimes reflects in different patterns of biodiversity in the Pantanal and in surrounding ecosystems, such as the Cerrado vegetation in the Pantanal plateau. The Kadiwéu Indigenous Territory is located in the ecotone between the Pantanal and Cerrado biomes, and therefore provides an ideal setting for monitoring biodiversity under different regimes of fire and flooding. In this doctoral thesis (“tese de doutorado, no Brasil”), I evaluated how different fire regimes, by influencing patterns of plant diversity, can affect the availability of flowers and fruits of tree and non-tree plants. In the same sense, I assess whether certain regimes may be most suitable over others, also considering the fertile period of the monitored plant species. Besides, we considered that fire may affect seed germinability of common species found in the Cerrado/Pantanal ecotone, as an example of Calliandra parviflora Benth. (Fabaceae). Calliandra parviflora, is well adapted to this environment due to its vegetative reproduction and these functional traits can be useful to choose species for ecological restoration. In general, my premises are based on the hypothesis of pyrodiversity, as a way of promoting biodiversity, for the design of technical recommendations. Here, we test pyrodiversity hypothesis on plant floral functional diversity, based on 21 years historical data series of spatiotemporal patters of fire in the study site. Moreover, we avaluate, how different fire frequencies and fire season can diverifies plant reproductive phenology. Contribuitions of my field studies, are presented in the three first chapters, I make technical recommendations for the integrated management of fire in wetlands, considering socio-environmental aspects. Moreover, in the fourth chapter, I present a case study focused on efforts to conserve the Hyacinth Macaw (Anodorhynchus hyacinthinus), which may be compromised by habitat and resources loss due to periods of extreme fire occurence, as recorded in 2020. In summary, we conclude that efforts for Integrated Fire Management in wetlands, such as the Pantanal and its surroundings, must be adaptive and include preventive measures against megafires. To this end, the maintenance of teams permanently providing educational and preventive work is essential, as is the work provided by the indigenous Kadiwéu Brigade, under the assistance and responsibility of competent environmental agencies. These brigades must be trained for constant technical updating according to scientific advances. Science must therefore be taken into consideration for ecological interventions with the use of fire in wetlands, as recommended in our papers and in the references that we consulted. The pyrodiversity, increases the beta-diversity of plant species, the high diversity of species reflects in high functional diversity in floral traits. In addition, diversification in fire regimes reduces the risk of burning plants in flowering and/or fruiting period, while diversifying phenological responses, ensuring the continued maintenance of flowers and fruits in fire-prone landscapes.