An assessment of the causes and consequences of agricultural land abandonment in Europe

The agriculture sector is the principal source of income for around 20% of the EU-26 population, which live in predominantly rural regions that would be devastated without its contribution. Moreover, the combined agricultural and food sector forms an important part of the EU economy, accounting for 15 million jobs (8.3% of total employment) and 4.4% of GDP. The 12 million active farmers across Europe today, have an average farm size of about 15 ha, and are expected to meet the needs of 500 million Europeans. In addition, they are also expected to promote a sustainable and balanced development of their land, also in areas where production conditions are difficult. Yet, despite the relevance of the sector, the use of land for agriculture purposes is not very sustainable. Among other issues, there is a serious problem in respect of the abandonment of agricultural land. Based on the perceived need for research on this topic, the aim of this paper is to examine the causes and consequences of agricultural land abandonment, outlining its social, economic and environmental impacts, as well as the implications for territorial integration

Gravel pits support waterbird diversity in an urban landscape

We assessed the benefit of 11 gravel pits for the settlement of waterbird communities in an urbanized area lacking natural wetlands. Gravel pits captured 57% of the regional species pool of aquatic birds. We identified 39 species, among which five were regionally rare. We used the Self Organizing Map algorithm to calculate the probabilities of presence of species, and to bring out habitat conditions that predict assemblage patterns. The age of the pits did not correlate with assemblage composition and species richness. There was a positive influence of macrophyte cover on waterbird species richness. Larger pits did not support more species, but species richness increased with connectivity. As alternative wetland habitats, gravel pits are attractive to waterbirds, when they act as stepping stones that ensure connectivity between larger natural and/or artificial wetlands separated in space

Quantifying soil hydrology to explain the development of vegetation at an ex-arable wetland restoration site

Wetland restoration frequently sets well-defined vegetation targets, but where restoration occurs on highly degraded land such targets are not practical and setting looser targets may be more appropriate. Where this more ‘open-ended’ approach to restoration is adopted, surveillance methods that can track developing wetland habitats need to be established. Water regime and soil structure are known to influence the distribution and composition of developing wetland vegetation, and may be quantified using Sum Exceedence Values (SEV), calculated using the position of the water table and knowledge of soil stress thresholds. Use of SEV to explain patterns in naturally colonizing vegetation on restored, ex-arable land was tested at Wicken Fen (UK). Analysis of values from ten locations showed that soil structure was highly heterogeneous. Five locations had shallow aeration stress thresholds and so had the potential to support diverse wetland assemblages. Deep aeration stress thresholds at other locations precluded the establishment of a diverse wetland flora, but identified areas where species-poor wetland assemblages may develop. SEV was found to be a useful tool for the surveillance of sites where restoration targets are not specified in detail at the outset and may help predict likely habitat outcomes at sites using an open-ended restoration approach

Forest Biomass Density across Large Climate Gradients in Northern South America is related to Water Availability but not with Temperature

Understanding and predicting the likely response of ecosystems to climate change are crucial challenges for ecology and for conservation biology. Nowhere is this challenge greater than in the tropics as these forests store more than half the total atmospheric carbon stock in their biomass. Biomass is determined by the balance between biomass inputs (i.e., growth) and outputs (mortality). We can expect therefore that conditions that favor high growth rates, such as abundant water supply, warmth, and nutrient-rich soils will tend to correlate with high biomass stocks. Our main objective is to describe the patterns of above ground biomass (AGB) stocks across major tropical forests across climatic gradients in Northwestern South America. We gathered data from 200 plots across the region, at elevations ranging between 0 to 3400 m. We estimated AGB based on allometric equations and values for stem density, basal area, and wood density weighted by basal area at the plot-level. We used two groups of climatic variables, namely mean annual temperature and actual evapotranspiration as surrogates of environmental energy, and annual precipitation, precipitation seasonality, and water availability as surrogates of water availability. We found that AGB is more closely related to water availability variables than to energy variables. In northwest South America, water availability influences carbon stocks principally by determining stand structure, i.e. basal area. When water deficits increase in tropical forests we can expect negative impact on biomass and hence carbon storage

Meta-analysis and the science of research synthesis

Meta-analysis is the quantitative, scientific synthesis of research results. Since the term and modern approaches to research synthesis were first introduced in the 1970s, meta-analysis has had a revolutionary effect in many scientific fields, helping to establish evidence-based practice and to resolve seemingly contradictory research outcomes. At the same time, its implementation has engendered criticism and controversy, in some cases general and others specific to particular disciplines. Here we take the opportunity provided by the recent fortieth anniversary of meta-analysis to reflect on the accomplishments, limitations, recent advances and directions for future developments in the field of research synthesis