Human influence on California fire regimes.

Periodic wildfire maintains the integrity and species composition of many ecosystems, including the mediterranean-climate shrublands of California. However, human activities alter natural fire regimes, which can lead to cascading ecological effects. Increased human ignitions at the wildland-urban interface (WUI) have recently gained attention, but fire activity and risk are typically estimated using only biophysical variables. Our goal was to determine how humans influence fire in California and to examine whether this influence was linear, by relating contemporary (2000) and historic (1960-2000) fire data to both human and biophysical variables. Data for the human variables included fine-resolution maps of the WUI produced using housing density and land cover data. Interface WUI, where development abuts wildland vegetation, was differentiated from intermix WUI, where development intermingles with wildland vegetation. Additional explanatory variables included distance to WUI, population density, road density, vegetation type, and ecoregion. All data were summarized at the county level and analyzed using bivariate and multiple regression methods. We found highly significant relationships between humans and fire on the contemporary landscape, and our models explained fire frequency (R2 = 0.72) better than area burned (R2 = 0.50). Population density, intermix WUI, and distance to WUI explained the most variability in fire frequency, suggesting that the spatial pattern of development may be an important variable to consider when estimating fire risk. We found nonlinear effects such that fire frequency and area burned were highest at intermediate levels of human activity, but declined beyond certain thresholds. Human activities also explained change in fire frequency and area burned (1960-2000), but our models had greater explanatory power during the years 1960-1980, when there was more dramatic change in fire frequency. Understanding wildfire as a function of the spatial arrangement of ignitions and fuels on the landscape, in addition to nonlinear relationships, will be important to fire managers and conservation planners because fire risk may be related to specific levels of housing density that can be accounted for in land use planning. With more fires occurring in close proximity to human infrastructure, there may also be devastating ecological impacts if development continues to grow farther into wildland vegetation.     

Inbreeding and local mate competition in the ant Cardiocondyla batesii

The ant species Cardiocondyla batesii is unique in that, in contrast to all other ant species, both sexes are flightless. Female sexuals and wingless, ergatoid males mate in the nest in autumn and young queens disperse on foot to found their own colonies in spring. The close genetic relatedness between queens and their mates (r_qm=0.76±SE 0.12) and the high inbreeding coefficient (F=0.55; 95%CI 0.45–0.65) suggest that 83% of all matings are between brothers and sisters. As expected from local mate competition theory, sex ratios were extremely female biased, with more than 85% of all sexuals produced being young queens. Despite the common occurrence of inbreeding, we could not detect any adult diploid males. Though the probability of not detecting multiple mating was relatively high, at least one-third of all queens in our sample had mated more than once. Multiple mating to some extent counteracts the effects of inbreeding on worker relatedness (r_ww=0.68±SE 0.05) and would also be beneficial through decreasing diploid male load, if sex was determined by a single locus complementary system.Communicated by L. Sundström     

Establishing minimum water level for Plastiras reservoir (Greece) combining water quality modelling with landscape aesthetics

A water quality model (MERES) is applied in the multi-purpose reservoir of Plastiras in Greece. The model was calibrated with limited field data using the standard trial and error procedure; next, it was applied for four scenarios of reservoir operation, which correspond to four values of minimum water levels (MWL). Model results were combined with landscape aesthetics to establish a “safe” MWL in the reservoir. MWL was proposed to be +784 m, a value that ensures a very good water quality by retaining the reservoir in the status of “a little beyond oligotrophic” and a very good quality of landscape with an acceptable area of dead zones; it also ensures an annual release of 127.5 hm³ of water within a reliability level of 90%. This quantity can be considered as acceptable from the water supply point of view.     

Using triple bottom line metrics and multi-criteria methodology in corporate settings

With the growing importance of environmental sustainability in the corporate sector, businesses are compelled to progress from assessing and benchmarking their environmental impact to making decisions on how to prioritize impact reduction alternatives. Most often, business decisions are driven by financial metrics, but with sustainability improvements becoming a business goal, it is also important to assess metrics from environmental and social spheres; nevertheless, practically and systematically performing such an assessment is challenging. We present an application of a multi-criteria decision analysis (MCDA) method that addresses the aforementioned challenges in a corporate setting. Our case study company – one of the largest inland marine freight carriers in the United States – promotes a business culture focused on financially viable, yet socially and environmentally responsible solutions. Thus, we combine life cycle analysis (LCA), financial calculation methods, and corporate surveys to quantify environmental, economic, and social performance measures, respectively. Multiattribute utility theory is integrated with analytic hierarchy processes (AHPs) and fuzzy analysis to create a carefully designed framework for corporations with diverse groups of stakeholders. With company leadership, implementation is feasible and successful at prioritizing alternatives among diverse stakeholders. The process provides a platform for negotiation and promotes discussions on decision drivers. The use of MCDA methodologies promoted the inclusion of a suite of metrics that aligned with the company's sense of social and environmental responsibility, generating an in-depth analysis of the alternatives that factored in other things besides economics. Return-on-investments (ROI) calculations, the typical approach used in the corporate setting, would have required significantly less time and effort from the company, but the results of our MCDA application indicated that inclusion of triple bottom line metrics delve deeper into stakeholder preferences. Thus, our case study company gained a holistic view of the candidate alternatives, in addition to creating a platform for structured discussions about company goals and priorities.     

How to feed the world sustainably: an overview of the discourse on agroecology and sustainable intensification

Regional Environmental Change - In order to combat hunger and feed a growing world population, adapt to climate change and reduce environmental impacts of unsustainable farming practices, the need...     

Spatio-temporal variability in fatty acid trophic biomarkers in stomach contents and muscle of Iberian sardine (<Emphasis Type="Italic">Sardina pilchardus</Emphasis>) and its relationship with spawning

Temporal variation in the fatty acid (FA) composition of stomach contents of Iberian sardines was compared to the relative contribution to dietary carbon made by different prey types for fish from two areas off Portugal. The effect of the FA content of the diet on sardine muscle FA composition was also studied, aiming at (1) analysing if FA biomarkers can be used as a complementary technique for the study of sardine diet and (2) to relate spatial and temporal variations of prey FA content with sardine condition and reproduction. Significant spatial differences in the FA composition of sardine diet occurred with concentrations of n-3 polyunsaturated FA, namely eicosapentaenoic acid [EPA, 20:5n-3] and linolenic acid 18:3n-3, being significantly higher in the diet of sardines from the west coast, whilst the diet of sardines from the south coast was richer in monounsaturated fatty acids (MUFA), namely the carnivory biomarker oleic acid 18:1n-9. These results are in agreement with the higher contribution made by diatoms and dinoflagellates to the diet of sardines off the west coast. Spatial variation in sardine dietary FA was also detected in their muscle composition, specifically for EPA, and the eicosapentaenoic/docosahexaenoic acid and (n-3)/(n-6) ratios, which were higher in sardines from the west coast. No difference in FA composition was detected between sexes, and the seasonal variability in sardine total FA concentration was primarily related to the seasonality of spawning. Sardines accumulate high concentrations of FAs during the resting stage of reproduction when the feeding intensity is similar or lower to that observed during the spawning season. Additionally, sardines show a high selective retention of MUFA and polyunsaturated FA (PUFA) throughout the year except at the beginning of the spawning season, when these FAs are largely invested in the formation of the gonads. Therefore, temporal and regional differences of prey environments are strong enough to be reflected in fish body composition, namely on the accumulation of essential FAs, which can have a strong impact on reproduction success for this species.     

Ex situ management as insurance against extinction of mammalian megafauna in an uncertain world

The persistence of endangered species may depend on the fate of a very small number of individual animals. In situ conservation alone may sometimes be insufficient. In these instances, the International Union for Conservation of Nature provides guidelines for ex situ conservation and the Convention on Biological Diversity (CBD) indicates how ex situ management can support the CBD's objectives by providing insurance policies for species. The circumstances that justify its use are uncertain. To evaluate the current in situ extinction risk and ex situ management of 43 critically endangered species of mammalian megafauna, we used nonmetric multidimensional scaling and geopolitical variables related to governance, economics, and national policy within their extant ranges. We then fitted generalized additive models to assess the contribution of each variable to the ordination. Fifteen (almost one-third) of the world's terrestrial mammalian megafauna are not the subject of any ex situ management. Seventy-three percent of these taxa occur in areas characterized by political uncertainty, such as border zones or areas affected by armed conflicts, mainly in Africa and the Middle East. A further 23% of taxa in ex situ programs do not meet sustainability criteria for inbreeding avoidance. Strategic conservation planning, such as the One Plan approach, may improve ex situ management for these taxa. Given the escalating trend in threats afflicting megafauna, ex situ management should be considered more rigorously, particularly in politically unstable regions, to achieve CBD Target 12 (prevent extinction of threatened species).