Articles publicats (CTFC)
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- ItemOpen AccessMechanisms underpinning community stability along a latitudinal gradient: Insights from a niche-based approach(Wiley, 2023) Evans, Luke C.; Melero, Yolanda; Schmucki, Reto; Boersch-Supan, Philipp H.; Brotons, Lluís; Fontaine, Colin; Jiguet, Frédéric; Kuussaari, Mikko; Massimino, Dario; Robinson, Robert A.; Roy, David B.; Schweiger, OliverAt large scales, the mechanisms underpinning stability in natural communities may vary in importance due to changes in species composition, mean abundance, and species richness. Here we link species characteristics (niche positions) and community characteristics (richness and abundance) to evaluate the importance of stability mechanisms in 156 butterfly communities monitored across three European countries and spanning five bioclimatic regions. We construct niche-based hierarchical structural Bayesian models to explain first differences in abundance, population stability, and species richness between the countries, and then explore how these factors impact community stability both directly and indirectly (via synchrony and population stability). Species richness was partially explained by the position of a site relative to the niches of the species pool, and species near the centre of their niche had higher average population stability. The differences in mean abundance, population stability, and species richness then influenced how much variation in community stability they explained across the countries. We found, using variance partitioning, that community stability in Finnish communities was most influenced by community abundance, whereas this aspect was unimportant in Spain with species synchrony explaining most variation; the UK was somewhat intermediate with both factors explaining variation. Across all countries, the diversity–stability relationship was indirect with species richness reducing synchrony which increased community stability, with no direct effects of species richness. Our results suggest that in natural communities, biogeographical variation observed in key drivers of stability, such as population abundance and species richness, leads to community stability being limited by different factors and that this can partially be explained due to the niche characteristics of the European butterfly assemblage.
- ItemOpen AccessSpatial and temporal variations of overstory and understory fuels in Mediterranean landscapes(Elsevier, 2021) Sánchez Pinillos, Martina; De Cáceres, Miquel; Casals, Pere; Álvarez, Albert; Beltrán, Mario; Pausas, Juli G. (Juli Garcia); Vayreda, Jordi; Coll Mir, LluísMediterranean forests are prone to fire and highly diverse in environmental conditions, species composition, and forest structure. While much is known about fire hazard and forest responses to fire in Mediterranean climate regions, our understanding of the spatial distribution of fuel characteristics and their dynamics remains incomplete. We hypothesized that fire hazard in heterogeneous Mediterranean regions is primarily explained by the variation in fuel loading and flammability characteristics of the understory layer across the landscape and over time. We used the Spanish National Forest Inventory data to estimate overstory and understory fuel characteristics, compare their spatial and temporal variations across Catalonia (NE Spain) over the last 25 years, and assess the role of climate conditions in explaining spatial distribution and dynamics of fuel characteristics. Our results showed that fuel characteristics strongly depend on the species composition of the overstory and understory layers. Fuel characteristics of both vegetation layers were significantly different and poorly correlated with each other. Although both strata showed significantly different rates of change in most fuel characteristics, the average changes were, in general, very small for the time window considered. Forests in the warmest and driest environments showed the highest flammability characteristics in both overstory and understory layers in contrast to mountain communities. We did not find, however, a remarkable effect of climatic conditions on the rates of change of fuel characteristics during the study period. Altogether, these findings confirm the importance of considering the spatial variation of fuel characteristics of different vegetation strata separately and provide critical information on forest vulnerability to develop appropriate fire mitigation policies in Mediterranean ecosystems.
- ItemOpen AccessUAVs for monitoring responses of regenerating forests under increasing climate change-driven droughts - a review(IOP Publishing, 2023) Luber, A.; Ramachandran, V.; Jaafar, W.S.W.M.; Bajaj, Shaurya; Miguel Magaña, Sergio de; Cardil Forradellas, Adrián; Doaemo, Willie; Mohan, MidhunThe impact of climate change-driven droughts on regenerating forests is poorly understood due to the complexities involved in regeneration processes and the difficulties in measuring the relevant parameters with sufficient spatial and temporal resolution in a timely manner. Drought increases tree mortality in both undisturbed and disturbed forests and may influence forest regeneration dynamics from seed germination to the recruitment, growth, and survival of tree seedlings. Seedlings and small saplings may be more susceptible to changes in water availability than larger individuals due to their shallower roots that may be unable to reach the deeper, moist soil layers, and due to uneven competition with adult trees for soil moisture. The potential range shifts and local extinction of drought-sensitive species can also result in changes in forest species community composition and diversity loss at different scales. There is a need for precise and low-cost monitoring systems that facilitate better capturing of the complexities of such processes for restoration measures. The objective of this paper is to study the use of UAVs (Unmanned Aerial Vehicles) for monitoring responses of regenerating forests under increasing climate change-driven droughts. UAVs have several advantages over traditional field-based monitoring techniques and flexibility in selecting the required spatiotemporal resolution over other remote sensing methods, making them a promising tool for monitoring forest recovery. Although further research is required to ensure the accuracy and effectiveness of UAV-facilitated measures for monitoring forest regeneration, UAVs possess great potential in forest management in the event of increasing occurrences of climate-change driven droughts.
- ItemOpen AccessAssessing Relativeness in the Provision of Urban Ecosystem Services: Better Comparison Methods for Improved Well-Being(MDPI, 2023) Krsnik, Goran; Reyes-Paecke, Sonia; Reynolds, Keith M.; Garcia Gonzalo, Jordi; González-Olabarria, José RamónIn this study, we evaluated alternative methods for comparing the provision of ecosystem services among urban areas, stressing how the choice of comparison method affects the ability to compare the ecosystem service outcomes, in order to improve the management actions in urban green areas, reduce environmental inequality, and ensure satisfactory levels of human well-being. For the analysis, ten spatial indicators were quantified to assess the provision of urban ecosystem services in Barcelona, Spain, and Santiago, Chile. Two comparison methods were applied in both cities to evaluate the differences in their provision scores. The analysis was performed using the Ecosystem Management Decision Support (EMDS) system, a spatially enabled decision support framework for environmental management. The results depicted changes in the values of the provision of ecosystem services depending on the methodological approach applied. When the data were analysed separately for each city, both cities registered a wide range of provision values across the city districts, varying from very low to very high values. However, when the analysis was based on the data for both cities, the provision scores in Santiago decreased, while they increased in Barcelona, showing relativeness and a discrepancy in their provisions, hindering an appropriate planning definition. Our results emphasise the importance of the choice of comparison approach in the analyses of urban ecosystem services and the need for further studies on these comparison methods.
- ItemOpen AccessEcosystem services provision by Mediterranean forests will be compromised above 2ºC warming(Wiley, 2021-07-06) Morán Ordóñez, Alejandra; Ramsauer, Julia; Coll Mir, Lluís; Brotons, Lluís; Améztegui González, AitorForests provide a wide range of provisioning, regulating and cultural services of great value to societies across the Mediterranean basin. In this study, we reviewed the scientific literature of the last 30 years to quantify the magnitude of projected changes in ecosystem services provision by Mediterranean forests under IPCC climate change scenarios. We classified the scenarios according to the temperature threshold of 2℃ set by the Paris Agreement (below or above). The review of 78 studies shows that climate change will lead to a general reduction in the provision of regulating services (e.g. carbon storage, regulation of freshwater quantity and quality) and a general increase in the number of fires, burnt areas and generally, an increase in climate-related forest hazards (median + 62% by 2100). Studies using scenarios above the 2℃ threshold projected significantly more negative changes in regulating services than studies using scenarios below this threshold. Main projected trend changes on material services (e.g. wood products), were less clear and depended on (i) whether or not the studies considered the interaction between the rise in temperatures and other drivers (e.g. forest management, CO2 fertilization) and (ii) differences in productivity responses across the tree species evaluated. Overall, the reviewed studies projected significant reductions in range extent and habitat suitability for the most drought-sensitive forest species (e.g. −88% Fagus sylvatica), while the amount of habitat available for more drought-tolerant species will remain stable or increase; however, the magnitude of projected change for these more xeric species was limited when high-end extreme climatic scenarios were considered (above Paris Agreement). Our review highlights the benefits that climate change mitigation (to keep global mean temperature increase <2℃) can bring in terms of service provision and conservation of Mediterranean forests.