Suchergebnisse

Iberian dehesas and montados are agroforestry systems protected by the European Habitats Directive due to high levels of biological diversity associated to their savannahlike structure. Tree scattering in dehesas, montados and other agroforestry systems is, however, known to compromise tree regeneration, although recent work suggests that it may protect tree populations from climate warming by alleviating plant-plant competition. We analyze how climatic conditions, tree isolation and their interactions influence the outcomes of regeneration stages, from flower production to early seedling establishment, using data gathered during the long-term monitoring (2001–2018) of ca. 300 Holm oak Quercus ilex trees located in central Spain. Holm oak reproductive effort, predispersal seed losses, and early seedling recruitment were sensitive to climate change, especially to year-round drought. Effort and early seedling recruitment decreased, while abortion and predispersal seed predation increased, with higher drought intensity. Spring warming increases pollination effectiveness, but had no further effect on acorn crops. Forest clearing seemed to have little scope to ameliorate these negative effects, as shown by weak or no interactive effects between the spatial configuration of trees (cover or isolation) and climate variables (spring temperature or drought intensity). Forest opening aimed at decreasing adult tree mortality under climate change scenarios would then have little or no effects on tree recruitment. Landscapescale rotations alternating shrub encroachment and thinning along periods adapted to changing climate are proposed as the main management option to preserve both oak forests and dehesas in the long term. ; This work was supported by the Projects QLK5-CT-2002-01495, FP7-KBBE-2008-227161, and PCIN-2016-159 (EU), 096/2002 and 003/2007 (Spanish National Parks), CGL2006-06647/BOS, CSD2008–00040, CGL2009-08430, CGL2010-22180-C03-03 and CGL2013-42271-P (Spanish National I + D + i Research Plans), and PGC2010-RNM-5782 (Andalucía regional government), now all ended, which provided partial financial support. TS-M was partially financed by a JAE-intro grant funded by the Spanish Research Council (CSIC). ; Peer reviewed

Received 27 December 2015, Revised 14 March 2016, Accepted 19 March 2016, Available online 31 March 2016 ; The effects of fragmentation on acorn production should be mediated by their impacts on the physiological status of oaks during seed development particularly in water-limited systems, such as Mediterranean forests. The creation of forests edges reduces tree-to-tree competition, which may in turn temper water shortage during summer and, as a result, enhance acorn production. To test these two hypotheses we monitored acorn production and predawn water potential during the 2012–2014 period in two holm oak (Quercus ilex) forest archipelagos of the Iberian Peninsula. Acorn production and fragmentation effects did not differ between localities despite of their contrasting climatic conditions (accumulated water deficit from April to August was a 60% higher in the South). In general, forest interiors showed a high proportion of non-producing trees (∼50%) while trees at small forest fragments showed high acorn crops (acorn score ⩾3, ∼40% of studied trees). Our results confirmed the expectation that intraspecific competition in small forest fragments was reduced, which alleviated summer water shortage of the trees studied. This reduced water stress entailed an increased acorn production. Overall, our results show that local processes such as fragmentation may counteract climatic differences among localities and could even override the impacts of increased aridity on acorn crops. ; We are also grateful to Laura Barrios for her help in the statistical analysis. Teresa Morán-López was beneficiary of a FPI grant (funded by the Spanish Government (BES-2011-048346). This paper is a contribution to the Spanish-funded projects VULGLO (CGL2010–22180-C03–03), VERONICA (CGL2013-42271-P) and REMEDINAL 2 & 3 (CM S2009 AMB 1783) (S2013/MAE-2719). ; Peer reviewed

We analyse the reply by Suárez et al. (2003) to our previous paper (Martínez et al., 2003), concluding that both reached the same general conclusion. The low quality of studies and evaluations of environmental impact assessment on birds is mostly due to a lack of interest and political will for using the information available and for detecting and solving relevant gaps in our knowledge. For this reason, the regulation of the Environmental Impact Assessment of projects is not applied efficiently in Spain. We also conclude that the disagreements between both papers refer mostly to details on (1) the relevance of gaps in basic information, (2) methods for using such information and (3) proposals to improve the quality of studies and evaluations. There are gaps in basic information, but a proper use of available sources which are seldom used would improve significantly studies and evaluations in the short term. Such sources are scientific papers on the biology of bird species and reports on the results of monitoring programs of the efficiency of correction measures of previous impacts. Increasing the scientific skills of technicians would improve the efficient use of these sources of information. Finally, the development of a variety of methods for the control of the quality of studies and evaluations, as well as of some regulations seldom used such as Territory Planning and Strategic Environmental Assessment, would further contribute to solve its general low quality. ; Peer Reviewed

Received 11 December 2015, Revised 1 March 2016, Accepted 3 March 2016, Available online 12 March 2016 ; Demographic and genetic connectivity of fragmented plant populations will depend on effective propagule flow across the landscape. We analyze functional connectivity in a holm oak (Quercus ilex) fragmented landscape by considering three important stages driving recruitment: effective pollination, acorn production and acorn dispersal. We used a network approach to (1) determine if pollen-mediated gene exchange across the landscape was spatially structured; (2) estimate the effects of limited acorn dispersal on functional connectivity; (3) identify which landscape traits could drive source–sink dynamics of gene flow. Although long distance dispersal was relatively frequent, most effective pollen flow occurred over short distances (10 ha) are the main pollen sources, while small ones (<1 ha) are important pollen sinks. Thus, big fragments are critical to maintain functional connectivity, while small forest fragments may provide acorn crops better representing regional genetic diversity. In addition to area effects, less isolated and more central fragments showed higher migration rates and exchanged effective pollen with more fragments. Hence, we expected that landscapes with uniform or clumped distribution of big forest fragments would show optimal connectivity traits. However, despite that simulated gene flow was more evenly distributed across the landscape, connectance and migration rates decreased. Our results call for caution before translating patch-level management guidelines to the landscape scale. They also show that the level of functional connectivity may change throughout the recruitment process, suggesting that large-scale conservation strategies may fail if local effective seed establishment is disregarded. ; TM-L was beneficiary of a FPI grant funded by the Spanish Government (BES-2011-048346). This paper is a contribution to the Spanish-funded projects VULGLO (CGL2010e22180-C03e03), VERONICA (CGL2013-42271-P) and REMEDINAL3eCM (S2013/MAE-2719). ; Peer reviewed

[EN] The next reform ofthe EU Common Agricultural Policy (CAP) for the period 2021-2027 (currently extended to 2023-2030) requires the approval by the European Commission of a Strategic Plan with environmental objectives for each Member State. Here we use the best available scientific evidence on the relationships between agricultural practices and biodiversity to delineate specific recommendations for the development of the Spanish Strategic Plan. Scientific evidence shows that Spain should (1) identify clear regional biodiversity targets and the landscape-level measures needed to achieve them; (2) define ambitious and complementary criteria across the three environmental instruments (enhanced conditionality, eco-schemes, and agri-environmental and climate measures) of the CAP's Green Architecture, especially in simple and complex landscapes; (3) ensure that other CAP instruments (areas of nature constraints, organic farming and protection of endangered livestock breeds and crop varieties) really support biodiversity; (4) improve farmers' knowledge and adjust measures to real world constraints; and (5) invest in biodiversity and ecosystem service monitoring in order to evaluate how the Plan achieves regional and national targets andto improve measures if targets are not met. We conclude that direct assessments of environmental objectives are technically and economi- cally feasible, can be attractive to farmers, and are socially fair and of great interest for improving the environmental effectiveness of CAP measures. The explicit and rigorous association of assessments and monitoring, relating specific environmental indicators to regional objectives, should be the main criterion for the approval of the Strategic Plan in an environmentally-focused CAP2023-2030. ; [ES] La reforma de la Política Agraria Común (PAC) para el periodo 2021-2027 (extendido en la actualidad a 2023-2030) exige que la Comisión Europea apruebe un Plan Estratégico por cada Estado Miembro con claros objetivos ambientales. En este trabajo desarrollamos recomendaciones específicas para la elaboración del Plan Estratégico para los sistemas agrícolas españoles, basadas en la mejor evidencia científica disponible sobre las relaciones entre la gestión agrícola y los componentes de la biodiversidad. La evidencia científica muestra que España debe 1) identificar objetivos regionales claros relativos a la biodiversidad de los medios agrarios y las medidas a nivel paisajístico necesarias para alcanzarlas; 2) definir criterios ambiciosos y complementarios para los tres instrumentos ambientales (condicionalidad extendida, eco-esquemas y medidas agroambientales y climáticas) de la Arquitectura Verde de la PAC, especialmente en paisajes sencillos y complejos; 3) garantizar que otros instrumentos de la PAC (zonas desfavorecidas, agricultura ecológica y protección de razas ganaderas y variedades de cultivos en peligro de extinción) favorecen realmente la diversidad biológica; 4) mejorar el conocimiento de los agricultores y ajustar las medidas a las limitaciones del mundo real; y 5) invertir en seguimiento de la biodiversidad y sus servicios ecosistémicos asociados con el fin de evaluar si el Plan alcanza los objetivos regionales y nacionales y mejorarlos adaptativamente si no lo consigue. Concluimos que la evaluación directa de los objetivos ambientales es técnica y económicamente viable, puede ser atractiva para los agricultores, es socialmente justa y de gran utilidad en la mejora de la efectividad de las medidas de la PAC. Una combinación rigurosa de seguimiento y evaluación de medidas y objetivos adaptados regionalmente mediante indicadores ambientales directos y claros debería ser el criterio que guíe la aprobación del Plan Estratégico para una PAC 2023-2030 centrada en el medio ambiente y orientada a la conservación de la biodiversidad. ; Peer reviewed

Conversion of semi-natural habitats, such as field margins, fallows, hedgerows, grassland, woodlots and forests, to agricultural land could increase agricultural production and help meet rising global food demand. Yet, the extent to which such habitat loss would impact biodiversity and wild species is unknown. Here we survey species richness for four taxa (vascular plants, earthworms, spiders, wild bees) and agricultural yield across a range of arable, grassland, mixed, horticulture, permanent crop, for organic and non-organic agricultural land on 169 farms across 10 European regions. We find that semi-natural habitats currently constitute 23% of land area with 49% of species unique to these habitats. We estimate that conversion of semi-natural land that achieves a 10% increase in agricultural production will have the greatest impact on biodiversity in arable systems and the least impact in grassland systems, with organic practices having better species retention than nonorganic practices. ; This work was funded by the European Union through FP7 project BioBio (Indicators for biodiversity in organic and low-input farming systems; www.biobio-indicator.org; Agreement Nr. 227161), by the Austrian Ministry for Science and Research, and by the Lendület program of the Hungarian Academy of Sciences. ; Peer reviewed