Due to the high content of viable seeds, topsoil is usually spread on ground left bare during railway and motorway construction to facilitate the regeneration of vegetation cover. However, during handling of the topsoil, seeds are often buried deeply and they cannot germinate or the seedlings cannot emerge from depth. This study experimentally explores the predictive value of seed mass for seed germination, mortality and seedling emergence at different burial depths for 13 common annual species in semiarid Mediterranean environments. We separate the effect of burial depth on germination and emergence by means of two experiments. In the germination experiment, five replicates of 20 seeds for each species were buried at depths ranging from 0 to 4 cm under greenhouse conditions. Germinated and empty or rotten seeds were counted after 8 weeks. In the emergence experiment, five replicates of four newly-germinated seeds per species were buried at the same depths under controlled conditions and emergence was recorded after 3 weeks. The effect of burial depth on percentage of germination and seedling emergence was dependent on seed size. Although all species showed a decrease in germination with burial depth, this decrease was greater for small-than large-seeded species. Percentage of emergence was positively related to seed mass but negatively related to burial depth. Seed mortality was higher for small-than large-seeded species, but there was no general effect of burial depth on this variable. Thus, the current practice of spreading 30 cm deep layers of topsoil in post-construction restoration projects is unadvisable. In this restoration scenario, thinner layers of topsoil should be used to achieve the maximum potential of the topsoil for germination and seedling establishment ; Financial support was received from the Spanish Ministry of Science and Innovation (Projects CGL2011-24871 and CGL2014-53789-R), the Madrid Regional Government (Project REMEDINAL3-P2013/MAE2719)
Depending on their response to grazing, grassland species can be categorized as grazing increasers or decreasers. Grazing by livestock includes several different activities that can impact species differently. Recent evidence suggest that one of these actions, dung deposition, can reduce the germinative performance of decreaser species, thus favouring increasers. The present study tested the hypothesis that decreased germinative success of decreaser species is caused by a greater activity of fungal pathogens under the influence of dung leachates. We performed a phytotron experiment analysing the germination and fungal infections of fourteen species from Mediterranean grasslands. Species were grouped into phylogenetically-related pairs, composed of an increaser and a decreaser species. Seeds of each species were germinated under four different treatments (control, dung leachate addition, fungicide addition and dung leachate and fungicide addition), and the differences in germination percentage, germination speed and infection rate between each increaser species and its decreaser counterpart were analysed. Decreaser species were more affected by mortality than increaser ones, and these differences were higher under the presence of dung leachates. The differences in germinative performance after excluding the effect of seed mortality did not differ between treatments, showing that the main mechanism by which dung leachates favour increaser species is through increased mortality of the seeds of decreaser species. Drastic reductions in the number of dead seeds in the treatments including fungicide addition further revealed that fungal pathogens are responsible for these differences between species with different grazing response. The different vulnerabilities of increaser and decreaser species to the increased activity of fungal pathogens under the presence of dung leachates seems the main reason behind the differential effect of these leachates on species with different grazing response ; Financial support was received from the Spanish MINECO (Project CGL2014- 53789-R) and the Madrid Regional Government (Project REMEDINAL3). CPC was supported by a Marie Curie Intra-European Fellowship within the 7th European Community Framework Programme (TANDEM; project id. 626392)
It is commonly accepted that species interactions such as granivory are more intense in the tropics. However, this has rarely been tested. A global dataset of post-dispersal seed removal by invertebrates and vertebrates for 79 native plant species from semi-natural and natural terrestrial habitats ranging from 55° N to 45° S, was compiled from the global literature to test the hypothesis that post-dispersal seed removal by invertebrates and vertebrates is more intense at lower latitudes. We also quantified the relationship between post-dispersal seed removal by vertebrates and by invertebrates to global climatic features including temperature, actual evapotranspiration (AET) and rainfall seasonality. Linear mixed effect models were applied to describe the relationships between seed removal and latitude, hemisphere and climatic variables controlling for the effect of seed mass. Post-dispersal seed removal by invertebrates was negatively related to latitude. In contrast, postdispersal seed removal by vertebrates was positively but weakly related to latitude. Mean annual temperature and actual evapotranspiration were positively related to post-dispersal seed removal by invertebrates, but not to post-dispersal seed removal by vertebrates, which was only marginally negatively related to rainfall seasonality. The inclusion of seed mass improved the fit of all models, but the term for seed mass was not significant in any model. Although a good climatic model for predicting post-dispersal seed predation by vertebrates at the global level was not found, our results suggest different and opposite latitudinal patterns of post-dispersal seed removal by invertebrates vs vertebrates. This is the first time that a negative relationship between post-dispersal seed removal by invertebrates and latitude, and a positive relationship with temperature and AET have been documented at a global-scale. These results have important implications for understanding global patterns in plant-animal interactions, and the factors that shape plant reproductive ecology, and also for predicting how this plant-animal interaction might respond to climate change ; This work was supported by the Spanish Ministry of Economy and Competition (Project CGL2011 24871), the Madrid Government (REMEDINAL2-S2009/AMB-1783), and the Spanish Ministry of Education (Salvador de Madariaga grant PR2011-0491 for the sabbatical of BP in the University of New South Wales). ATM was supported by a QEII fellowship from the Australian Research Council
This is the peer reviewed version of the following article: Functional Ecology 29.4 (2015): 579-588, which has been published in final form at http://dx.doi.org/10.1111/1365-2435.12366. This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Self-Archiving ; Ecologists use approaches based on plant functional traits to tackle several fundamental and applied questions. Although a perfect characterization of functional trait structure requires the measurement of all the individuals in communities, this is prohibitively resource-consuming. Consequently, the general practice is to average the trait values of a reduced number of individuals per species. However, there are different alternatives regarding the number, identity and spatial location of the individuals chosen to calculate species-averaged trait values. In this study, we compared different strategies for sampling functional traits, using community-weighted mean trait values (CWM) and the Rao index of functional diversity (FD). We intensively sampled the functional trait structure along a topographical gradient in a Mediterranean grassland, obtaining accurate estimations of the 'real' values of these indices (CWMI and FDI) for three traits (height, leaf area and specific leaf area). We simulated three different sampling strategies differing in the spatial location of the individuals used to estimate species-mean trait: (i) average of the whole gradient (GLO), (ii) average of the sampling unit in which the abundances of species maximize (MAX) and (iii) average of a reduced number of individuals per species and sampling unit (LOC). For each strategy, we simulated different sampling intensities (number of individuals sampled). For each trait, we examined the ability of each strategy and sampling intensity to accurately estimate CWMI and FDI, as well as their ability to detect changes in functional trait structure along the topographical gradient. LOC outperformed the other strategies in terms of accuracy and bias, and was much more efficient to describe changes along the gradient, regardless of the traits and indicators considered. Furthermore, LOC was the only strategy that improved consistently as sampling intensity increased, especially at low levels of intensity. Our results indicate that the impact of considering intraspecific variability in trait values can be greater than commonly assumed. Strategies that neglect this source of variability can result in inaccurate or biased estimations of the functional trait structure of plant communities. Most importantly, we show that intraspecific variability can be taken into consideration without any increases in the total number of individuals measured ; Financial support was received from the Spanish Ministry of Science (Project CGL2011-24871), the Madrid Regional Government (Project REMEDINAL3), and the Spanish Ministry of Education (FPU AP2012-2849 for CR). CPC was supported by a Marie Curie Intra-European Fellowship within the 7th European Community Framework Programme (TANDEM; project id. 626392)
This is the peer reviewed version of the following article: Journal of Vegetation Science 26.3 (2015): 538-551, which has been published in final form at http://dx.doi.org/10.1111/jvs.12260. This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Self-Archiving. ; Questions: How do inter-annual fluctuations in water availability affect the functional trait patterns along spatial gradients of resource availability and disturbance? Location: Mediterranean grasslands in central Spain, near Madrid. Methods: We surveyed plant communities from 66 sites under different grazing regimes (from heavy grazing to grazing abandonment) in productive and unproductive habitats (corresponding to upper and lower topographic zones) in 2 yr with contrasting rainfall conditions. Community weighted mean (CWM) and Rao quadratic entropy for three key plant ecological strategy traits (specific leaf area, height and seed mass) were calculated for each community. We used null models to estimate functional richness (FR) and functional divergence (FD), the two components of functional diversity with the highest power to detect changes in community assembly processes across environmental gradients. Results: The patterns of CWM remained rather constant across years, with the only exception being seed mass, which experienced considerable temporal changes that suggested that heavy-seeded species are favoured under stressful conditions. Patterns for FR were consistent across years. They revealed both trait convergence and divergence depending on the niche axis and context. Convergence was observed for vegetative traits in unproductive habitats and seed mass in productive ones, and divergence for seed mass in unproductive habitats and vegetative traits in productive ones. In contrast, the patterns of FD of the vegetative traits changed considerably between years, as shown by increased divergence during the wet year in unproductive habitats and decreased divergence in grazing-abandoned productive habitats. Conclusions: Temporal changes in Mediterranean grassland composition depend on complex interactions between species traits, resource availability and disturbance. Increased rainfall appeared to have contrasting effects on assembly processes in stressful and productive habitats. In stressful habitats we found evidence that increased rainfall promoted niche complementarity, while in productive habitats, especially in the absence of disturbance, it increased trait convergence ; Financial support was received from the Spanish Ministry of Science (Projects CGL2007-63382 and CGL2011-24871), the Madrid Regional Government (Projects REMEDINAL- S0505/AMB-0335 and REMEDINAL2-S2009/AMB-1783), and the Spanish Ministry of Education (FPI for Carlos Pérez Carmona)
[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
Analysing temporal patterns in plant communities is extremely important to quantify the extent and the consequences of ecological changes, especially considering the current biodiversity crisis. Long-term data collected through the regular sampling of permanent plots represent the most accurate resource to study ecological succession, analyse the stability of a community over time and understand the mechanisms driving vegetation change. We hereby present the LOng-Term Vegetation Sampling (LOTVS) initiative, a global collection of vegetation time-series derived from the regular monitoring of plant species in permanent plots. With 79 data sets from five continents and 7,789 vegetation time-series monitored for at least 6 years and mostly on an annual basis, LOTVS possibly represents the largest collection of temporally fine-grained vegetation time-series derived from permanent plots and made accessible to the research community. As such, it has an outstanding potential to support innovative research in the fields of vegetation science, plant ecology and temporal ecology. ; The authors acknowledge institutional support as follows. Nicola J. Day: Te Apārangi Royal Society of New Zealand (Rutherford Postdoctoral Fellowship). Jiří Danihelka: Czech Science Foundation (project no. 19-28491X) and Czech Academy of Sciences (project no. RVO 67985939). Francesco de Bello: Spanish Plan Nacional de I+D+i (project PGC2018-099027-B-I00). Eric Garnier: La Fage INRA experimental station. Tomáš Herben: GAČR grant 20-02901S. Anke Jentsch: German Federal Ministry of Education and Research (grant 031B0516C - SUSALPS) and Oberfrankenstiftung (grant OFS FP00237). Norbert Juergens: German Federal Ministry of Education and Research (grant 01LG1201N - SASSCAL ABC). Frédérique Louault and Katja Klumpp: AnaEE-France (ANR-11-INBS-0001). Robin J. Pakeman: Strategic Research Programme of the Scottish Government's Rural and Environment Science and Analytical Services Division. Meelis Pärtel: Estonian Research Council (PRG609) and European Regional Development Fund (Centre of Excellence EcolChange). Josep Peñuelas: Spanish Government (grant PID2019-110521GB-I00), Fundación Ramon Areces (grant ELEMENTAL-CLIMATE), Catalan Government (grant SGR 2017-1005), and European Research Council (Synergy grant ERC-SyG-2013-610028, IMBALANCE-P). Ute Schmiedel: German Federal Ministry of Education and Research (Promotion numbers 01LC0024, 01LC0024A, 01LC0624A2, 01LG1201A, 01LG1201N). Hana Skálová: GAČR grant 20-02901S. Karsten Wesche: International Institute Zittau, Technische Universität Dresden. Susan K. Wiser: New Zealand Ministry for Business, Innovation and Employment's Strategic Science Investment Fund. Ben A. Woodcock: NERC and BBSRC (NE/N018125/1 LTS-M ASSIST - Achieving Sustainable Agricultural Systems). Enrique Valencia: Program for attracting and retaining talent of Comunidad de Madrid (no. 2017-T2/AMB-5406) and Community of Madrid and Rey Juan Carlos University (Young Researchers R&D Project. Ref. M2165 – INTRANESTI). Truman P. Young: National Science Foundation (LTREB DEB 19-31224). ; Peer reviewed
