Lost forever? Ecosystem functional changes occurring after agricultural abandonment and forest recovery in the semiarid Chaco forests

Aedes aegypti oviposition dynamics in towns with low human population density in yungas and dry chaco, Salta, Argentina

We assessed the presence of Aedes aegypti in five ecorregions of Salta province and compared the oviposition activity of Ae. aegypti using ovitraps in towns of two contrasting ecoregions (yungas and Chaco dry forests) in the province of Salta, Argentina, a major contrast in these ecoregions are rain patterns and altitude. Our aim was to estimate how oviposition activities were associated with the ecoregion and site scale local environmental variables. Mosquito oviposition activity was monitored weekly during the summer using ovitraps. Predictor variables were ecoregion, town, and meteorological variables. The effect of the predictor variables was measured on the response variables using multi-model inference. Besides yungas, the presence of Aedes aegypti was confirmed in towns of dry Chaco and High Monte. The only factor that had a significant effect on the presence of eggs in the ovitraps was the ecoregion, with the frequency of positives being higher in yungas. For the number of eggs, the ecoregion, the night temperature of the first week and the NDVI would explain said variable. Overall, results indicate that the variations between towns would be more related with their ecological and climatic characteristics than with the more immediate meteorological variations.

A Scientometrics Review on Land Ecosystem Service Research

Humans can derive the benefits from the ecosystem to satisfy human needs as well-being. Therefore, good ecosystem management is the intermediary between ecosystems and human well-being. The ecosystem services depend on the supply of nature, and also reflect the value orientation of human beings, as the basis for the realization of human survival and cultural development. Land ecosystem services are the core and hot topic of ecological research. Under the current severe depletion of land use, this research evaluates the sustainable governance on the natural resource shortage, serious environmental pollution and ecosystem degradation. Based on the Web of Science database, this paper analyzes the development characteristics and trends of global land ecosystem services research using the Bibliometrix software package. The results show that (1) the amount of literature on land ecosystem services research between 2000 and 2019 has generally increased significantly, and entered a stage of rapid development from 2015. (2) Developed countries are the main research force in the field of land ecosystem services, and the United States has the absolute leading position. Developing countries are dominated by China, Argentina, and Brazil. (3) The high-frequency keywords for land ecosystem services are land use change, land use, climate change, urbanization, carbon and water quality. This can be regarded as a research hotspot in the field of land ecosystem services to a certain extent. (4) Through cluster analysis on the big data, the research found the direction for the future land ecosystem services, mainly: (I) the restoration of degraded land and its impact on ecosystem services; (II) the environmental impact assessment of land use planning based on the ecosystem services value; (III) the tradeoff analysis of ecosystem services in sustainable land management; (IV) the impact of land cover change on ecosystem services; (V) through the historical analysis of citied papers, the research history and evolution path of land ecosystem services are explored. Based on all these arguments, a comprehensive study on the diverse facets of land ecosystem services and the practical application of land ecosystem services areas is proposed.

Are Ecological Modernization Narratives Useful for Understanding and Steering Social-Ecological Change in the Argentine Chaco?

During the past decades, the Ecological Modernization Theory, and associated ideas such as the Forest Transition Theory and Land Sparing Hypothesis, have dominated the academic and policy arenas regarding the solutions to current environmental crises. However, critiques were raised as these theories, originally conceived for developed countries, started to be applied in developing countries for explaining and prescribing social-ecological transitions. Here, we assess the validity of five key assumptions of Ecological Modernization narratives as applied to the Argentine Chaco, a global deforestation hotspot. We reviewed existing literature and conducted straightforward analysis to disentangle relationships among key variables. Although agriculture intensified, there is no evidence that this intensification inhibited agricultural expansion. Rural depopulation took place between 2001 and 2010; however, deforestation rates did not decrease, and the quality of life of migrants did not increase compared to those that stayed in rural areas. Our review suggests that the consequences of agriculture intensification on biodiversity and the provision of multiple ecosystem services exceeds the area used. Therefore, available evidence does not support the assumed causal relationships of Ecological Modernization, and even contradicts most assumptions. We propose a series of analytical shifts to better capture the complexity of social-ecological transitions in modern commodity frontiers.

Impact of Farmland Abandonment on Water Resources and Soil Conservation in Citrus Plantations in Eastern Spain

Due to the reduction in the prices of oranges on the market and social changes such as the ageing of the population, traditional orange plantation abandonment in the Mediterranean is taking place. Previous research on land abandonment impact on soil and water resources has focused on rainfed agriculture abandonment, but there is no research on irrigated land abandonment. In the Valencia Region—the largest producer of oranges in Europe—abandonment is resulting in a quick vegetation recovery and changes in soil properties, and then in water erosion. Therefore, we performed rainfall simulation experiments (0.28 m2; 38.8 mm h−1) to determine the soil losses in naveline orange plantations with different ages of abandonment (1, 2, 3, 5, 7 and 10 years of abandonment) which will allow for an understanding of the temporal changes in soil and water losses after abandonment. Moreover, these results were also compared with an active plantation (0). The results show that the soils of the active orange plantations have higher runoff discharges and higher erosion rates due to the use of herbicides than the plots after abandonment. Once the soil is abandoned for one year, the plant recovery reaches 33% of the cover and the erosion rate drops one order of magnitude. This is related to the delay in the runoff generation and the increase in infiltration rates. After 2, 3, 5, 7 and 10 years, the soil reduced bulk density, increase in organic matter, plant cover, and soil erosion rates were found negligible. We conclude that the abandonment of orange plantations reduces soil and water losses and can serve as a nature-based solution to restore the soil services, goods, and resources. The reduction in the soil losses was exponential (from 607.4 g m−2 in the active plot to 7.1 g m−2 in the 10-year abandoned one) but the water losses were linear (from 77.2 in active plantations till 12.8% in the 10-year abandoned ones).