Abstract: Birds are an important part of the agricultural landscape, as having nature value, but also as pest control agents and bio-indicators for the health of the environment. Here we look at linear non-crop elements in agricultural areas as a potential source of food for nestlings of avian species. We measured invertebrate availability as it relates to structural complexity at the local and landscape levels in three counties in central Illinois. Invertebrates were measured with taxonomic diversity, abundance, and estimated biomass during spring of 2012 and 2013. Our study shows that easily modifiable field edge characteristics have the greatest impact on invertebrate diversity and abundance, as compared to field and landscape features. This finding shows that a potential invertebrate food source as measured by both diversity and biomass, may be easily enhanced without changes to agricultural practices.
Abstract: Land use and land cover (LULC) patterns play an important role in the establishment and spread of invasive plants. Understanding LULC changes is useful for early detection and management of land-use change to reduce the spread of invasive species. The primary objective of this study is to analyze and predict LULC changes in Connecticut. LULC maps for 1996, 2001 and 2006 were selected to analyze past land cover changes, and then potential LULC distribution in 2018 was predicted using the Multi-Layer Perceptron Markov Chain (MLP_MC) model. This study shows that the total area of forest has been decreasing, mainly caused by urban development and other human activity in Connecticut. The model predicts that the study area will lose 5535 ha of deciduous forest and gain 3502 ha of built-up area from 2006 to 2018. Moreover, forests near built-up areas and agriculture lands appear to be more vulnerable to conversion. Changes in LULC may result in subtle spatial shifts in invasion risk by an abundant invasive shrub, Japanese barberry (Berberis thunbergii). The gain of developed areas at the landscape scale was most closely linked to increased future invasion risk. Our findings suggest that the forest conversion needs to be controlled and well managed to help mitigate future invasion risk.
Abstract: Smallholder farming in the Brazilian Amazon has changed markedly over the last few decades, following a pervasive swing to cattle production observed across the basin. These changes have brought opportunities for accumulating a modicum of wealth that were not available in the early stages of colonization. At the same time, they have reconfigured livelihood systems away from diversified agriculture to a strong engagement with the cattle economy. They are also exposing smallholders to new forms of exploitation by transnational corporations, seeking to pass risk upstream to less powerful economic agents who provide inputs to production, such as calves. The case of Southeastern Pará provides a natural laboratory for investigating such phenomena, which the article considers through the presentation of data from field research conducted in the region over the past decade. Here, agrarian reform efforts have been particularly intense, and social movements have often espoused a green rhetoric in favor of diversified agriculture, even though smallholders show little interest in anything but cattle. Household level incentives promote Amazonia’s emergent cattle economy, demonstrating how global production networks have reached into the basin, where production relations between smallholders provisioning calves to large ranching operations often resemble what has been referred to in the literature as “contract farming” land grabs, given the exploitive terms of trade.
Abstract: Few land disturbances impact watersheds at the scale and extent of mountaintop removal mining (MTM). This practice removes forests, soils and bedrock to gain access to underground coal that results in likely permanent and wholesale changes that impact catchment hydrology, geochemistry and ecosystem health. MTM is the dominant driver of land cover changes in the central Appalachian Mountains region of the United States, converting forests to mine lands and burying headwater streams. Despite its dominance on the landscape, determining the hydrological impacts of MTM is complicated by underground coal mines that significantly alter groundwater hydrology. To provide insight into how coal mining impacts headwater catchments, we compared the hydrologic responses of an MTM and forested catchment using event rainfall-runoff analysis, modeling and isotopic approaches. Despite similar rainfall characteristics, hydrology in the two catchments differed in significant ways, but both catchments demonstrated threshold-mediated hydrologic behavior that was attributed to transient storage and the release of runoff from underground mines. Results suggest that underground mines are important controls for runoff generation in both obviously disturbed and seemingly undisturbed catchments and interact in uncertain ways with disturbance from MTM. This paper summarizes our results and demonstrates the complexity of catchment hydrology in the MTM region.
Abstract: Urban ecosystems are carrying an extinction debt. Mitigating this debt will require the development of a predictive framework that improves our understanding of the factors causing decline of native biodiversity in urban areas. I argue that nitrogen is a common currency around which such a predictive framework could be built. I first summarise the evidence that shows the probable extent of nitrogen enrichment in urban ecosystems. I then review the body of empirical evidence that describes how nitrogen enrichment affects ecosystem process and function. By unifying these two bodies of empirical evidence, I generate a series of testable hypotheses that may allow for a better understanding of native biodiversity loss in urban areas.
Abstract: Botswana is a semi-arid, middle-income African country that imports 90 percent of its food. Despite its relative prosperity, Botswana also suffers from one of the highest measures of income inequality in the world, persistent poverty, and relatively high levels of food insecurity. The objective of this paper is to explore how political economy, climate change and livelihood dynamics are synergistically impacting household food security. The major finding is that the marginalization of smallholder farming in Botswana has as much or more to do with domestic, regional and international political economy as it does with climate change. As such, international efforts to support climate change adaptation in Botswana will have a limited effect on smallholder farming livelihoods and rural food security unless such efforts take account of political economic constraints. Effective support must be based on a grounded understanding of the real drivers of marginalization and food insecurity. One initiative that merits further exploration is the government’s backyard gardening initiative, which could be viewed as a pro-poor climate adaptation strategy. The findings of this paper are based on semi-structured interviews with policymakers and surveys with urban, peri-urban and rural households undertaken in 2012 and 2015.