Biodiversity loss along a gradient of deforestation in Amazonian agricultural landscapes

Abstract

Assessing how much management of agricultural landscapes, in addition to protected areas, can offset biodiversity erosion in the tropics is a central issue for conservation that still requires cross-taxonomic and landscape-scale studies. We measured the effects of Amazonia deforestation and subsequent land-use intensification in 6 agricultural areas (landscape scale), where we sampled plants and 4 animal groups (birds, earthworms, fruit flies, and moths). We assessed land-use intensification with a synthetic index based on landscape metrics (total area and relative percentages of land uses, edge density, mean patch density and diversity, and fractal structures at 5 dates from 1990 to 2007). Species richness decreased consistently as agricultural intensification increased despite slight differences in the responses of sampled groups. Globally, in moderately deforested landscapes species richness was relatively stable, and there was a clear threshold in biodiversity loss midway along the intensification gradient, mainly linked to a drop in forest cover and quality. Our results suggest anthropogenic landscapes with high-quality forest covering >40 % of the surface area may prevent biodiversity loss in Amazonia.

Land Use Change in Coastal Cities during the Rapid Urbanization Period from 1990 to 2016: A Case Study in Ningbo City, China

“…Forest degradation can also increase surface runoff and decrease groundwater recharge, which finally results in water shortages and increased flood risk and flood severity in coastal regions [79,80]. Besides, a loss of biodiversity is an inevitable consequence of forest degradation and its accompanying agricultural intensification [81,82]. In this context, forest degradation in coastal hilly areas should be strictly controlled through spatial regulations.…”

Tree Diversity Reduces Fungal Endophyte Richness and Diversity in a Large-Scale Temperate Forest Experiment

“…Rapid environmental and anthropogenic changes are altering patterns of biodiversity worldwide, degrading ecosystem productivity, function, and services [1,2]. Increased temperatures and human activities over the last century have reduced forest habitats by 50%, which has subsequently diminished plant and animal diversity [3][4][5][6]. Declining biodiversity will likely have important implications for human wellbeing, as decades of research in land and seascapes have demonstrated a positive relationship between biodiversity and critical ecosystem services (e.g., increasing plant productivity, supporting diverse faunal communities, regulating nutrient cycles, and buffering ecosystems against climate change; reviewed by [7,8]).…”

Anthropogenic Soils Promote Biodiversity in Amazonian Rainforests

“…Modern human activity has been associated with negative environmental impacts in the Amazon 3,18 , but on the other hand, historical human footprints associated with ADEs appear to have "positive" effects on the Amazonian ecosystem 47 . For instance, we found that old forests on ADEs were the most biodiverse LUS.…”

“…Although deforestation rates in Amazonia have been showing 64 a generally decreasing trend over the last decade, human activities in the region were still 65 responsible for losses of 7,900 km 2 of its natural vegetation in 2018 alone 1 . Many forested 66 areas have become highly fragmented, and may be reaching tipping points where 67 biodiversity and ecosystem functions may be dramatically affected 2,3 , potentially leading to 68 cascading effects that impact ecosystem services over a much larger area 4,5 . 69…”