Identification of priority areas for landscape connectivity maintenance in the Xingu Area of Endemism in Brazilian Amazonia

Abstract

Forest fragmentation has been intense in the eastern Amazon region, which has negatively affected wildlife populations. The speed of deforestation in this region underscores the urgent need to understand the effects of such changes on populations of endemic species, and to implement measures for ecosystem conservation. We analyzed the extent to which fragmented forests are still connected in the Xingu Area of Endemism, in the eastern Brazilian Amazon, and assigned conservation priority to fragments most important for connectivity maintenance. We structurally classified the Xingu landscape using the Morphological Spatial Pattern Analysis and ranked each fragment according to its importance using an Index of Connectivity. Our data revealed important differences in conservation potential across the region. Although most of the study area already receives some degree of protection, future conservation actions should prioritize the connection of habitat fragments to maximize dispersal potential and minimize genetic isolation of biodiversity components. We produced a map of prioritary areas for connectivity maximization. These areas include fragments with large core areas and high-quality fragments that provide connection among habitats which, together, should maintain crucial corridors for gene flow in a biologically-rich region of the Amazon.

Forest fragmentation and its potential implications for the management of the Tarumã-Açu River basin, Central Amazon, Brazil

“…This diagnosis converges with the studies by Numata and Cochrane (2012), Haddad et al (2015) and Hansen et al (2020), whose data showed an increase in the number of fragments < 10 ha in Amazonian forests, where there is a numerical predominance of patches smaller than 100 ha. Concerning hydrographic basins as a territorial unit, several studies have found similar results, both in the Amazon and in other biomes (Jesus et al, 2015;Rusca et al, 2017;Rex et al, 2018;Lisboa et al, 2019;Andrade et al, 2020;Cavalcante et al, 2020;Castro et al, 2020;Thiago et al, 2020).…”

“…Although small fragments generally function as habitat sinks (Odum and Barret, 2008) in very anthropized matrices -is the case of the TARB low basin region -these scattered patches can function as ecological "stepping stones" or connection points, facilitating the flow of some species in the landscape (Saura et al, 2014;Andrade et al, 2020). Managing strategies for these fragments should be considered in watersheds management plans (Castro et al, 2020;Cavalcante et al, 2020;Thiago et al, 2020), aiming at maintaining and/or increasing connectivity with larger fragments. These, in turn, although in smaller numbers (Class V: NUMP = 9), represent 88.15% of the forest areas (Figure 2B), and function as sources for eco-hydrological processes, standing out in importance for the resilience and sustainability capacity of the watershed landscape (Jesus et al, 2015).…”

“…As recorded by Castro et al (2020) in the Xingu Endemism Area, the conflict of interests and the potential for exploiting varied natural resources (water, forests, soils, non-metallic minerals) shaped the occupation and transformation of the Tarumã-Açu basin landscape. The impacts of forest cover loss are possibly aggravated by reducing fragment size, creating edges and reducing connectivity (structural and functional).…”

“…Thus, the planning and use of network strategies can present better results for Tarumã-Açu basin landscape conservation/restoration. As proposed by Haddad et al (2015) and Castro et al (2020), these strategies can initially focus on prioritizing the protection of those fragments with high connectivity potential (IIC and PC), which are not protected; the enrichment of buffer zones of small fragments with fast growing native species in the low course, due to the urban use already consolidated in this region; and effective land use planning.…”

“…Following fragmentation studies in Amazonian environments (e.g. Rusca et al, 2017;Lisboa et al, 2019;Santos et al, 2019;Andrade et al, 2020;Castro et al, 2020;Duarte et al, 2020), we apply the metrics described in Table 1 to characterize the structural and functional patterns of the TARB landscape. The selection included metrics that, according to Baranyi et al (2011), Saura et al (2011) and Ziólkowska et al (2014), Thiago et al (2020).…”