Galicio-portuguese oak forest of Quercus robur and Quercus pyrenaica:biodiversity patterns and forest response to fire

Tese de doutoramento, Biologia (Ecologia), 2009, Universidade de Lisboa, Faculdade de CiênciasDisponível no document

Highly productive sown biodiverse pastures with low invasion risk

Driscoll et al. (1) have recently drawn attention to the risk of new pasture plants becoming invasive, because the same biological traits that promote pasture productivity may also facilitate the invasion of natural areas. The authors indicate some aspects that could mitigate the risk of invasion: namely, the use of native species to develop new pasture plants, the avoidance of new characteristics associated with environmental weeds, and the selection of new characteristics that limit invasion risk. Here we describe a system that meets the above criteria—specifically, the last one—through the existence of a mismatch between the environmental conditions found in managed and in natural areas, such that improved pasture plants face environmental limitations in natural areas while keeping a high performance in managed ones. The system of sown biodiverse permanent pastures rich in legumes (SBPPRL) has been successfully implemented in Portugal on farms in Mediterranean climate areas (2, 3). SBPPRL were developed by Portuguese agronomists, namely David Crespo, as a response to the low levels of productivity and feed quality obtained in seminatural pastures. The pastures’ low performance results from endogenous low soil fertility and historical land use practices that depleted soil nutrients, disrupted soil structure, and caused plant community impoverishment, especially the decline of legume species (4). SBPPRL consist in mixtures of up to 20 taxa of grasses and legumes, each mixture tailored to local environmental conditions (e.g., precipitation and soil texture) to best cover the available environmental niches. Seed mixtures include autochthonous (the majority) and exotic species (all native to the Mediterranean basin) selected to achieve the best performance in soils with enhanced fertility. Legumes and associated Rhizobium fix atmospheric nitrogen, making the system self-sufficient in nitrogen, but require an external input of phosphorus (a limiting nutrient in Mediterranean soils) and the correction of soil acidity for optimal legume growth (5). As result, improved cultivars are not competitive in oligotrophic environments with acidic soils (i.e., natural environments) but outcompete spontaneous pasture plants in managed systems. This aspect not only contributes to the longterm persistence of SBPPRL but also to reducing their invasive risk. In fact, the older SBPPRL are now over 30 y old, and there are no reports of exotic pasture species establishment outside ruderal or managed pasture habitats (i.e., in natural ecosystems). Moreover, SBPPRL offer an alternative for sustainable intensification by combining higher pasture productivity (i.e., socio-economic benefits) with environmental benefits that emerge as positive externalities, such as soil carbon sequestration and soil restoration, both associated with the absence of tillage in SBPPRL and the accumulation of soil organic matter (3, 4). Additionally, the use of phosphorus fertilization is more than compensated by the avoided impacts of using nitrogen fertilizers (otherwise required either to produce concentrate feed or fertilize pastures), and potential leaching of phosphorus is mitigated by increased soil organic matter (4). The opportunities for society of SBPPRL were acknowledged by the Portuguese Carbon Fund* through the payment of soil carbon sequestration (2009– 2014) in around 50,000 ha, in an estimated total of 1 million tons of CO2 (2).info:eu-repo/semantics/publishedVersio

Fire regime as a driver of resilience, functional diversity and ecosystem services in Mediterranean mountains

Mountain areas in Portugal are usually defined as territories with rough morphology, low demographic densities, and peculiar agrarian systems based on cattle raising and husbandry. The use of fire has been a common management practice in traditional land use, mainly to control vegetation encroachment and to promote pasturelands. Therefore, historically fire has been a strong driver of vegetation patterns, soil properties and ecosystem services throughout Iberian mountains. Recently, however, a generalized tendency for abandonment of agriculture and pastoralism is promoting vegetation recovery and changes in fire regimes, driving a shift from small fires in recurrently burnt areas to energetic and largely unpredictable wildfires. We present results from studies of ecosystem resilience and vegetation dynamics driven by fire regimes, discussing their connection to the provision of ecosystem services. We report strong effects of fire recurrence, distance to the latest wildfire, and geology on scrubland resilience, with potential implications for regulating services. We also evaluated the resistance and resilience of young deciduous forests to fire disturbance and its implications for supporting services. Overall, our results support the idea that fire regime is a major driver of functional diversity in Mediterranean mountains and suggest that land abandonment and related shifts in fire regimes promote unpredictability in the spatiotemporal patterns of several ecosystem services. Finally, we discuss response options for managing changing mountain landscapes

Modeling soil water dynamics and pasture growth in the montado ecosystem using MOHID land

The southern Iberian Peninsula is characterized by evergreen oak woodlands (locally known as montado), which constitute an important savanna-type agro-silvo-pastoral ecosystem. This ecosystem is facing a progressive decline for several reasons, with the foremost being overgrazing. Better management tools are necessary to accurately quantify the systems’ carrying capacity and the sustainable stocking rates that prevent land degradation. The purpose of this study was to determine whether the MOHID-Land model could adequately simulate soil water dynamics and pasture growth in the montado ecosystem. The study area was located in the Alentejo region of southern Portugal. The model successfully simulated soil water contents and aboveground biomass during the 2010–2011 and 2011–2012 growing seasons, producing acceptable errors of the estimates (0.015 RMSE 0.026 cm3 cm3; 279 RMSE 1286.5 kg ha1), and relatively high modeling efficiencies (0.481 EF 0.882). The model was further used to simulate the same variables for a longer period (1979/2009 seasons), to account for the effect of climate variability on model estimates. Water balance and dry biomass estimates were found to be significantly different between rainfed and irrigated pastures, as well as between the ten driest and ten wettest seasons, with the model responding well to climate variability. The results showed the potential of using the MOHID-Land model for improving pasture management in the montado ecosysteminfo:eu-repo/semantics/publishedVersio

Modelling impacts of drivers on biodiversity and ecosystems

Purpose of this chapter: Explores key issues in modelling impacts of changes in direct drivers on biodiversity and ecosystems; and critically reviews major types of models for generating outputs that are either directly relevant to assessment and decision-support activities, or are required as inputs to subsequent modelling of nature’s benefits to people. Key findings: 1-Models of biodiversity and ecosystem function are critical to our capability to predict and understand responses to environmental change; 2- There is a need to match biodiversity and ecosystem function model development to stakeholder and policy needs; 3- Biodiversity and ecosystem modelling depends heavily on our understanding of ecosystem structure, function and process and on their adequate representation in models; 4- Uncertainty in ecosystem dynamics is inherent in ecosystem modelling.EEA Santa CruzFil: Brotons, Lluís. InForest jru. Creaf-Ctfc; EspañaFil: Christensen, Villy. The University of British Columbia; Canadá.Fil: Ravindranath, N. H. India Center for Sustainable Technologies. Indian Institute of Science; India.Fil: Cao, Mingchang. Keqiang Zhao; China.Fil: Chun, Jung Hwa. National Institute of Forest Science, Division of Forest Ecology; Corea del SurFil: Maury, Olivier. Institut de Recherche pour le Développement (IRD); Francia.Fil: Peri, Pablo Luis. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Santa Cruz; Argentina.Fil: Peri, Pablo Luis. Universidad Nacional de la Patagonia Austral; Argentina.Fil: Peri, Pablo Luis. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina.Fil: Proença, Vânia. Instituto Superior Tecnico - UNIU Lisboa; Portugal.Fil: Salihoglu, Baris. Middle East Technical University. Institute of Marine Sciences; Turquí

Interacting regional-scale regime shifts for biodiversity and ecosystem services

Current trajectories of global change may lead to regime shifts at regional scales, driving coupled human–environment systems to highly degraded states in terms of biodiversity, ecosystem services, and human well-being. For business-as-usual socioeconomic development pathways, regime shifts are projected to occur within the next several decades, to be difficult to reverse, and to have regional- to global-scale impacts on human society. We provide an overview of ecosystem, socioeconomic, and biophysical mechanisms mediating regime shifts and illustrate how these interact at regional scales by aggregation, synergy, and spreading processes. We give detailed examples of interactions for terrestrial ecosystems of central South America and for marine and coastal ecosystems of Southeast Asia. This analysis suggests that degradation of biodiversity and ecosystem services over the twenty-first century could be far greater than was previously predicted. We identify key policy and management opportunities at regional to global scales to avoid these shifts

Biodiversity and resilience of ecosystem functions

Accelerating rates of environmental change and the continued loss of global biodiversity threaten functions and services delivered by ecosystems. Much ecosystem monitoring and management is focused on the provision of ecosystem functions and services under current environmental conditions, yet this could lead to inappropriate management guidance and undervaluation of the importance of biodiversity. The maintenance of ecosystem functions and services under substantial predicted future environmental change (i.e., their ‘resilience’) is crucial. Here we identify a range of mechanisms underpinning the resilience of ecosystem functions across three ecological scales. Although potentially less important in the short term, biodiversity, encompassing variation from within species to across landscapes, may be crucial for the longer-term resilience of ecosystem functions and the services that they underpin

A synthesis is emerging between biodiversity–ecosystem function and ecological resilience research: reply to Mori

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