Differing short-term impacts of agricultural tarping on soil-dwelling and surface-active arthropods

Agricultural tarping, the practice of placing impermeable plastic tarps over crop beds before planting to suppress weeds, is rising in popularity. However, the use of tarps has uncertain effects on soil arthropod communities. We studied the impact of silage (black plastic) tarps and clear plastic tarps on surface-active and soil-dwelling arthropods by tracking immediate impacts and arthropod recovery for 5 weeks after tarps were removed. We also assessed how well environmental and experimental variables explained arthropod diversity and composition. During tarp application, we found that both silage and clear plastic tarps had significant negative impacts on surface-active arthropod diversity, while only clear plastic tarps impacted soil-dwelling arthropods. Surface-active arthropod diversity recovered by 1-3 weeks after tarping, but at 5 weeks after tarping soil-dwelling arthropod diversity was significantly lower in silage tarp and clear plastic plots than control plots. Tarps also led to compositional changes in the arthropod communities, though these changes were only significant during tarp cover. The variables that best explained arthropod diversity and community composition were treatment (i.e., silage tarp, clear plastic tarp, or control) during tarping and farm site after tarps were removed. Other variables, such as soil moisture and weed coverage, were not strong model predictors. These results imply that tarps may have temporary impacts on surface-active arthropods but potentially longer-lasting impacts on soil-dwelling arthropods. Continuing to monitor impacts on tarps on soil arthropods will better inform the sustainability of this practice

Biases and limitations of Global Forest Change and author-generated land cover maps in detecting deforestation in the Amazon.

Studying land use change in protected areas (PAs) located in tropical forests is a major conservation priority due to high conservation value (e.g., species richness and carbon storage) here, coupled with generally high deforestation rates. Land use change researchers use a variety of land cover products to track deforestation trends, including maps they produce themselves and readily available products, such as the Global Forest Change (GFC) dataset. However, all land cover maps should be critically assessed for limitations and biases to accurately communicate and interpret results. In this study, we assess deforestation in PA complexes located in agricultural frontiers in the Amazon Basin. We studied three specific sites: Amboró and Carrasco National Parks in Bolivia, Jamanxim National Forest in Brazil, and Tambopata National Reserve and Bahuaja-Sonene National Park in Peru. Within and in 20km buffer areas around each complex, we generated land cover maps using composites of Landsat imagery and supervised classification, and compared deforestation trends to data from the GFC dataset. We then performed a dissimilarity analysis to explore the discrepancies between the two remote sensing products. Both the GFC and our supervised classification showed that deforestation rates were higher in the 20km buffer than inside the PAs and that Jamanxim National Forest had the highest deforestation rate of the PAs we studied. However, GFC maps showed consistently higher rates of deforestation than our maps. Through a dissimilarity analysis, we found that many of the inconsistencies between these datasets arise from different treatment of mixed pixels or different parameters in map creation (for example, GFC does not detect reforestation after 2012). We found that our maps underestimated deforestation while GFC overestimated deforestation, and that true deforestation rates likely fall between our two estimates. We encourage users to consider limitations and biases when using or interpreting our maps, which we make publicly available, and GFC's maps

Projected losses of ecosystem services in the US disproportionately affect non-white and lower-income populations

Social inequalities may be reflected in how ecosystem services are distributed among groups of people. Here the authors estimate the distribution of three ecosystem services across demographic and socioeconomic groups in the US between 2020 and 2100, finding that non-white and lower-income groups disproportionately bear the loss of ecosystem service benefits