TY - JOUR A1 - Estrany, Joan A1 - Ruiz, Maurici A1 - Calsamiglia, Aleix A1 - Carriqui, Marc A1 - Garcia-Comendador, Julian A1 - Nadal, Miquel A1 - Fortesa, Josep A1 - López-Tarazón, José Andrés A1 - Medrano, Hipolito A1 - Gago, Jorge T1 - Sediment connectivity linked to vegetation using UAVs BT - High-resolution imagery for ecosystem management JF - The science of the total environment : an international journal for scientific research into the environment and its relationship with man N2 - In this study, a low-cost unmanned aerial vehicle was used to obtain multi-spectral high-resolution imagery (1.4 cmpx(-1)) from2 microcatchments (3.3 ha) with burned Mediterranean shrubland and pine forests. This imagery was used to calculate the blue normalized differential vegetation index and to generate digital elevation models for estimating the sediment connectivity index. Both indices enabled an integrated approach for deciphering how hydrological and sediment connectivity interact with vegetation as well as soil conservation structures. The application of spatial analysis improves our understanding of the feedback between biological and geomorphological processes. Local spatial data analysis established a significant link between local geomorphological and biological factors, enabling a precise identification of homogeneous areas at micro-catchment scale and the minimal size of vegetation units reacting to geomorphology as natural groups at plot-scale where management strategies and efforts should be applied. Establishing this local relationship between sediment connectivity and vegetation patterns through new and interdisciplinary methodologies represents a new strategy for the assessment of ecosystem dynamics and management. KW - Ecogeomorphology KW - Mediterranean shrubland KW - Burned areas KW - UAVs KW - BNDVI KW - Sediment connectivity Y1 - 2019 U6 - https://doi.org/10.1016/j.scitotenv.2019.03.399 SN - 0048-9697 SN - 1879-1026 VL - 671 SP - 1192 EP - 1205 PB - Elsevier CY - Amsterdam ER - TY - JOUR A1 - Metz, Johannes A1 - Tielboerger, Katja T1 - Spatial and temporal aridity gradients provide poor proxies for plant-plant interactions under climate change: a large-scale experiment JF - Functional ecology : an official journal of the British Ecological Society N2 - 1. Plant-plant interactions may critically modify the impact of climate change on plant communities. However, the magnitude and even direction of potential future interactions remains highly debated, especially for water-limited ecosystems. Predictions range from increasing facilitation to increasing competition with future aridification. 2. The different methodologies used for assessing plant-plant interactions under changing environmental conditions may affect the outcome but they are not equally represented in the literature. Mechanistic experimental manipulations are rare compared with correlative approaches that infer future patterns from current observations along spatial climatic gradients. 3. Here, we utilize a unique climatic gradient in combination with a large-scale, long-term experiment to test whether predictions about plant-plant interactions yield similar results when using experimental manipulations, spatial gradients or temporal variation. We assessed shrub-annual interactions in three different sites along a natural rainfall gradient (spatial) during 9 years of varying rainfall (temporal) and 8 years of dry and wet manipulations of ambient rainfall (experimental) that closely mimicked regional climate scenarios. 4. The results were fundamentally different among all three approaches. Experimental water manipulations hardly altered shrub effects on annual plant communities for the assessed fitness parameters biomass and survival. Along the spatial gradient, shrub effects shifted from clearly negative to mildly facilitative towards drier sites, whereas temporal variation showed the opposite trend: more negative shrub effects in drier years. 5. Based on our experimental approach, we conclude that shrub-annual interaction will remain similar under climate change. In contrast, the commonly applied space-for-time approach based on spatial gradients would have suggested increasing facilitative effects with climate change. We discuss potential mechanisms governing the differences among the three approaches. 6. Our study highlights the critical importance of long-term experimental manipulations for evaluating climate change impacts. Correlative approaches, for example along spatial or temporal gradients, may be misleading and overestimate the response of plant-plant interactions to climate change. KW - annual plant communities KW - climate manipulation KW - competition KW - facilitation KW - Mediterranean shrubland KW - nurse plant KW - rainfall gradient KW - Sarcopoterium spinosum KW - semi-arid KW - stress-gradient hypothesis Y1 - 2016 U6 - https://doi.org/10.1111/1365-2435.12599 SN - 0269-8463 SN - 1365-2435 VL - 30 SP - 20 EP - 29 PB - Wiley-Blackwell CY - Hoboken ER -