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Rural depopulation, abandonment of traditional land uses and decrease of extensive stockfarming is accelerating shrub encroachment in mountain areas. In NW Spain, gorse ( Ulex gallii Planch.) is expanding, developing dense shrublands that accumulate high fuel-loads, ignite easily and persist during long periods as alternate stable states. Under this scenario, traditional bush-to-bush farming fires are being replaced by high fuel-load burnings performed by specialised teams to reduce fuels and promote mosaic landscapes. This research analyses the effects on soil function and nitrogen (N)-cycling of these new generation of prescribed fires practiced under similar conditions to traditional fires (winter time, moist soils), but differing in the biomass and the continuity of the surface burnt. The results showed significant changes in N-cycle parameters, such as increases in inorganic N and dissolved organic nitrogen (DON), but declines in N microbial biomass and urease activity. At the ecosystem level, potential N losses were high because the pulse of water-soluble forms, DON and nitrate, following fire overlaps with periods of low biological N retention by microorganisms and plants. Although most effects were similar to those observed in traditional burnings done in the same region, the primary concern is the high potential for DON losses following prescribed burning in highly gorse-encroached areas. In N-limited ecosystems, a crucial issue is to attain an equilibrium between frequent burnings, which may prevent an optimal recovery of the soil function, and uneven burnings, which burn high amounts of accumulated fuel and increase the risk of removing large quantities of dissolved N from the ecosystem in a unique fire event. Overall, the use of different techniques combined with fire are needed to promote and consolidate desired changes in dense gorse lands. [ABSTRACT FROM AUTHOR]

Abstract: Continental freshwater, irrespective of its origin, natural or artificial, may contribute significantly to biodiversity conservation. Because of the decline of natural aquatic habitats, an increasing concern exists about the role of water ponds as spots of biological richness. Amphibians are strongly at risk since the loss of aquatic habitats, among other factors, causes the isolation of their populations. The implementation of livestock ponds as artificial wetlands may be an effective measure for enhancing amphibian decaying communities. This policy assumes that managing ponds for wildlife conservation purposes joins livestock welfare requirements, but this hypothesis has not been specifically studied. The purpose of this research is to evaluate this premise in the Urbasa-Andia Natural Park, a high-valuable environmental area that holds a relevant amphibian community and has an extended grazing history. We analyse the relationship between the amphibian assemblages present and the design and attributes of a variety of drinking points previously chosen by embodying a high environmental heterogeneity of water resources. The results of this study indicate that the quality of the water stored varies largely along the season, degrading severely in summer because of the wading of animals (in unfenced ponds) and the low water recharge. The contamination, caused by increased enteric microorganisms and dissolved N, is likely to affect livestock more severely than amphibian populations, since the sensitive breeding stage of many amphibians occurs before the loss of water quality. Although the quality of the water is essential, and mammals (wild and domestic) have an influence on it, other factors that are less considered by environmental managers emerge as main drivers of amphibian assemblages, such as hydroperiod, predator occurrence and the environmental quality of the surrounding habitat. [Copyright &y& Elsevier]

In the southern Pyrenees, human population and therefore land uses have changed from forests to pastures, then crops, and back to pastures and secondary forests during the last two centuries. To understand what such rapid land use changes have meant for carbon (C) and nitrogen (N) stocks, we used data from two forest sites in the western Pyrenees, combined with regional data on pastures and crop production (potato, cereal), to calibrate the ecosystem-level model FORECAST. Then, we simulated 150 years of land use for each site, emulating historical changes. Our estimates show that the conversion from forests into pastures and crops created C and N deficits (378–427 Mg C ha −1 , 4.0–4.6 Mg N ha −1 ) from which these sites are still recovering. The main ecological process behind the creation of these deficits was the loss of the ecological legacy of soil organic matter (SOM) created by the forest, particularly during conversion to farming. Pastures were able to reverse, stop or at least slow down the loss of such legacy. In conclusion, our work shows the deep impact of historical land use in ecosystem attributes, both in magnitude of removed C and N stocks and in duration of such impact. Also, the usefulness of ecological modeling in absence of historical data to estimate such changes is showcased, providing a framework for potential C and N stocks to be reached by climate change mitigation measures such as forest restoration. [ABSTRACT FROM AUTHOR]