Assessing the effects of alternative fuel treatments to reduce wildfire exposure

Effective landscape-scale fuel management strategies are essential for reducing wildfire risk in Mediterranean fire-prone areas.In this study,the minimum travel time(MTT)fire-spread algorithm as implemented in FlamMap was applied to assess the potential of alternative fuel treatments for lowering wildfire losses in a 5,740-ha study area in eastern Sardinia,Italy.Twenty-seven wildfires at 10-m resolution were simulated considering three wind speeds(15,18,and 21 km h-1)to compare fuel treatments:no treatment(NT),irrigated agroforestry areas with shrub clearing(T1),prescribed fire in eucalyptus stands(T2),and irrigated grasslands(T3).The simulations replicated a recent large wildfire that occurred in the study area(Orrìwildfire,2019)and considered the weather and fuel moisture conditions associated with this event.The average wildfire exposure outputs(burned area,probability of burning,conditional flame length,potential crown fire occurrence,and surfaces withflame lengths above 2.5 m)decreased after fuel treatments,compared to no treatment.T1 was the most effective strategy in mitigating wildfire hazards and provided the most significant performance for several wildfire exposure indicators.Treating only 0.5%of the study area(~30 ha)resulted in a decrease in all wildfire exposure metrics to~10%within the study area.In addition,the total surface characterized by high flame length(average>2.5 m)was the lowest in the T1 treatment.This study can help land and fire managers optimize fuel treatment opportunities and wildfire risk mitigation strategies in Mediterranean areas.

Congruent responses of vascular plant and ant communities to pastoral land-use abandonment in mountain areas throughout different biogeographic regions

Background:There is a long-term trend towards the abandonment of agro-pastoral activities in the mountain areas of Europe:the following encroachment process of semi-natural grasslands by shrubs is one of the main severe threats to the conservation of biodiversity in mountain environments.To better understand the impact of land abandonment,we analysed the reliability of plant functional groups,ant traits,and ant functional groups as indicators of land use changes.We carried out the research in Italy at four sites along a latitudinal/altitudinal gradient in three biogeo-graphic regions(Mediterranean,Continental,Alpine).We identified three stages of a chronosequence at each site as representative of the plant succession in response to pastoral land-use abandonment.Results:As expected,both the plant and ant assemblages considerably differed across sites at the species level and,within each site,among the three stages.This trend was found also using ant traits,functional groups of ants,and plant functional groups.Ant and plant communities were related in terms of composition and functionality.Harvester ants and ants with collective foraging strategy were associated with annual legumes and grasses(Therophytes);ants with a strictly individual foraging strategy with Phanerophytes.Ant traits and plant functional groups indicated significant differences among the three stages of the chronosequence.However,ant functional groups could not discriminate between the stages represented by secondary grasslands currently grazed and shrub-encroached grasslands ungrazed.Conclusion:Despite some limitations of ant functional groups in explaining the succession stages of land abandonment,our results suggest that ants are a good surrogate taxon and might be used as bioindicators of land-use changes and ecosystem functioning.Furthermore,our findings indicate that the functional group approach should be applied to other European ecosystems.Finally,reducing the taxonomic complexity could contribute to developing predictive models to detect early environmental changes and biodiversity loss in mountain habitats.