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Grazing exclusion may be used to promote the recovery of disturbed ecosystems. A promising way for the evaluation of its effectiveness is through the monitoring of key biological groups, particularly those more responsive to disturbance and playing key roles in ecosystem functioning. Ants have been used as ecological indicators as they are abundant, diverse and sensitive to environmental changes. Here, we aimed to evaluate changes in ant taxonomic and functional structure and diversity, using functional groups, along a post-grazing succession in a Mediterranean oak woodland and to understand which environmental variables drive them. The post-grazing succession comprised a chronosequence of grazing excluded sites for 8, 12 and 18 years and a grazed control site. We found that ant species richness, functional structure and diversity increased with years since grazing exclusion: Generalist/Opportunist and the Hot Climate specialists increased in the 18 years grazing excluded site, while the Cryptic Species group increased in the 12 years grazing excluded site. Yet, their responses were not linear over time. Time since grazing exclusion and vegetation structure explained differences in ant taxonomic and functional structure and diversity. The Invasive/Exotic group dominated in all sites, except in the longest excluded site, where it occurred in the lowest proportion. The invasive Argentine ant dominated the grazed site, where it may have led to ant taxonomic and functional homogenization. Our results suggest that the time and changes in habitat structure may favour the recovery of ant biodiversity, although the presence of the invasive Argentine ant species may have slowed it down. [ABSTRACT FROM AUTHOR]

Semi-arid areas are particularly susceptible to the loss of biodiversity as a consequence of global change. Species functional traits are key drivers of functioning and resilience of ecosystems, thus monitoring of functional trait diversity is urgently needed. The assessment of functional diversity requires the quantification of species and/or their traits in the field, though there is no consensus on the best plant-sampling method to be used. The aim of this study was to compare the performance of the point-intercept (PT) method with two area-based approaches, the modified-Whittaker (MW) and Dengler (DE) methods, to assess functional diversity in semi-arid areas. The herbaceous community of a savanna-like Mediterranean woodland was surveyed at the two extremes of a regional precipitation gradient (dry to wet). Efficiency in the quantification of species/ traits, precision of cover estimates, and their effect on functional diversity metrics computed for eight functional traits were compared. Results showed that the examined methods differed in their efficiency in quantifying species/traits in both sites. With the DE method, fewer species were detected than with the MW and PT methods, which yielded similar values. The PT method had a higher precision in the quantification of both dominant and non-dominant species/traits. It also had a higher community evenness, mainly in the wet location, which allowed the analysis of a greater number of species/traits within the 80% "dominance" threshold (i.e., species representing 80% of the relative cover of community), a critical aspect of functional diversity assessments. In addition, the PT method yielded higher estimates for multi-trait functional evenness, as well as different estimates (either higher or lower than MW and DE) of single-trait community weighted means (for N-fixing ability and flowering onset), functional dispersion (for N-fixing ability and specific leaf area), and functional evenness (for height and flowering onset). In spite of the observed differences among methods in the assessment of functional diversity, the PT approach demonstrated important advantages in the non-destructive, fine-scale monitoring of semi-arid areas, where "less dominant" species may play a critical role. [ABSTRACT FROM AUTHOR]

Understanding forest regeneration at sites previously used for agriculture underlies the establishment of science-based woodlands management policies. This is especially relevant in semi-arid areas, where the tree cover is critical in ameliorating the effects of aridity and in preventing desertification and land degradation. Natural regeneration in semi-arid areas occurs very slowly, which in part explains why it has hardly been studied. In the present work, we sought to devise a method to predict the natural regeneration potential of woodlands in semi-arid areas, to be used in guiding restoration efforts. Specifically, we evaluated holm oak coverage at a long-term ecological research site and then designed and validated a model to predict the natural regeneration of holm oak based on a few environmental variables. Unlike available studies, we obtained long-term information on tree regeneration (making use of >60 years of aerial photography) and climate (using long-term climate and microclimate data). We found that microclimate, measured using the potential solar radiation as a proxy, was a key driver of natural regeneration: after 60 years of agricultural abandonment, less sun-exposed areas attained a tree cover >90 %, whereas in more sun-exposed areas it remained below 20 %. We then used the model to map the natural regeneration potential, first in the study area and then in an area where holm oak plantations had been unsuccessfully introduced. In the latter case, the model successfully predicted the failure of this reforestation effort. Our results support the use of this model by decision makers to optimize management practices, as it will encourage the concentration of efforts in areas more prone to successful reforestation and allow the identification of areas more likely to benefit from natural regeneration processes. [ABSTRACT FROM AUTHOR]

Adaptation Pathways is a decision support tool designed to create adaptation policies under different climate change scenarios. This tool has been used successfully in several sectors and contexts such as coastal and river adaptation, urban heat waves, floods and rural livelihoods but its use in natural resource management, has faced several challenges and limitations. In the sector of agroforestry its use has seldom been done or documented and one of the reasons for this may due to some of its specific challenges. In this study, these challenges were addressed when using the Adaptation Pathways for the adaptation planning of three case studies in the semi-arid Alentejo region, a Mediterranean dryland of southern Portugal. This tool was integrated in a participatory approach combined with the Scenario Workshop method, to plan the adaptation of the agriculture and forestry sector of one municipality (Mértola) and two agroforestry farms (221 ha and 1000 ha). The methodology included, for each case study, 20 interviews, two workshops, literature review, expert analysis and the use of indicators of efficacy of adaptation measures, to define tipping points. The adaptation process and the resulting adaptation plans were evaluated by questionnaire and expert review. This combination of methods has supported the choice of effective adaptation measures for the case studies and when combined with several adaptation pathways and a landscape approach it supported the creation of integrated climate change adaptation plans that are now in implementation. We discuss how this combination of methods deals with limitation to Adaptation Pathways identified in the literature, conclude that the method was able to create adaptation plans that are now under implementation and present avenues for future research. • There is a growing need for climate adaptation planning and decision making support tools. • Participatory adaptation planning in the field of agroforestry has rarely been done or documented. • Adaptation Pathways approach was successfully used in three case studies. • Limitations of Adaptation Pathways were addressed and discussed. [ABSTRACT FROM AUTHOR]

In temperate areas, vegetation seasonality and phenology have been mostly associated with temperature changes both in space and time. In drylands, where water is the most limiting factor, we expect that they strongly respond to water availability. The degree to what that response depends more on precipitation that occurred when vegetation seasonality and phenology were measured, or on the long-term precipitation, is not fully known. We hypothesize that in drylands, long-term precipitation better explains the patterns of seasonality and phenology metrics than concurrent one, due to constrains imposed by ecosystem legacy. We correlated long-term precipitation (30 years normal) and concurrent precipitation (12 years) to several seasonal metrics (MODIS, average of 12 years) measured in a savannah-like system, Mediterranean evergreen woodlands, located in southwest Europe (Portugal). We observed that seasonal metrics of productivity and phenology were more significantly related with long-term precipitation than with concurrent precipitation. Comparing the extremes of our gradient we found that drier areas (c. 496 mm long-term annual precipitation) showed average growth cycles of annual plants 25 days shorter and ended 16 days sooner than more rainy regions (c. 739 mm). Evergreen vegetation productivity was shown to be c. 30% lower in drier areas. Moreover, productivity and phenology metrics were non-linearly related to the long-term precipitation, suggesting both are particularly constrained below 600–650 mm. These results suggest a memory effect in the response of vegetation to climate, most probably associated to legacies on soil characteristics and on plant community. It also indicates the existence of ecosystem response thresholds in vegetation's response to precipitation along ecosystem transitions. Overall, this method can be used to track ecosystem services over space in drylands and for managing ecosystems for both mitigation and adaptation to climate change. [ABSTRACT FROM AUTHOR]