245 research outputs found

    A geographically flexible approach for mapping the Wildland-Urban Interface integrating fire activity data

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    The Wildland-Urban Interface (WUI) is the area where houses and natural vegetation meet or intermingle. WUI areas are exposed to an increased hazard of wildfires and have significantly expanded worldwide in the past few decades. In this study, we developed a new empirical approach for mapping the WUI by generating a WUI index based on the juxtaposition among buildings, vegetation, and the fire history of the study area. We first calculated the percentage coverage of buildings and three different fuel typologies within circular moving windows with radii of 100, 250, and 500 m, and then acquired the fire history data between 2012 and 2021 for Israel and the West Bank (Palestinian Authority) from the VIIRS active fires remote sensing product. We defined the WUI as cells where the combination of vegetation cover and building cover had more VIIRS fire detections than expected by chance. To assess the effects of using broad vs. local scale parameterizations on resulting WUI maps, we repeated this process twice, first using national-scale data, and then separately in four distinct geographic regions. We assessed the congruence in the amounts and patterns of WUI in regions as mapped by information from these two analysis scales. We found that the WUI in Israel and the West Bank ranged from 0.5% to 1.7%, depending on fuel type and moving window radius. The scale of parameterization (national vs. regional) affected the WUI patterns only in one of the regions, whose characteristics differed markedly than the rest of the country. Our new method differs from existing WUI mapping methods as it is empirical and geographically flexible. These two traits allow it to robustly map the WUI in other countries with different settlement, fuel, climate and wildfire characteristics

    A global analysis of factors controlling VIIRS nighttime light levels from densely populated areas

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    Remote sensing of nighttime lights has been shown as a good surrogate for estimating population and economic activity at national and sub-national scales, using DMSP satellites. However, few studies have examined the factors explaining differences in nighttime brightness of cities at a global scale. In this study, we derived quantitative estimates of nighttime lights with the new VIIRS sensor onboard the Suomi NPP satellite in January 2014 and in July 2014, with two variables: mean brightness and percent lit area. We performed a global analysis of all densely populated areas (n = 4153, mostly corresponding to metropolitan areas), which we defined using high spatial resolution Landscan population data. National GDP per capita was better in explaining nighttime brightness levels (0.60 45% of the variability in cities' nighttime brightness, when both physical and socio-economic variables were included. Within the generalized linear model, the percent of national GDP derived from income (rents) from natural gas and oil, was also found as one of the statistically significant variables. Our findings show that cities' nighttime brightness can change with the seasons as a function of vegetation and snow cover, two variables affecting surface albedo. Explaining cities' nighttime brightness is therefore affected not only by country level factors (such as GDP), but also by the built environment and by climatic factors

    Are environmental transitions more prone to biological invasions?

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    Aim To examine whether at a subcontinental-scale ecotonal areas of transition between vegetation communities are at higher risk of plant invasion. Location South Africa and Lesotho. Methods Using plant data on native and established alien species in South Africa, we examined the relationship between plant richness (native and alien) in each grid cell (quarter-degree resolution) in the study area and the distance of the grid cell to the nearest ecotone between vegetation communities. We used a residual analysis to estimate each grid cell's relative invasibility (i.e. susceptibility to invasion) relative to its ecotone distance. We further explored the relative importance of ecotones in relation to large-scale environmental variation, and the importance of ecotonal spatial heterogeneity, in structuring alien species richness patterns. Results Both alien and native richness patterns become higher with declining distance to ecotones, suggesting that transitional environments are more susceptible to invasion than areas located farther away; however, levels of invasibility vary across South Africa. The negative relationship between ecotone distance and alien species richness remained negative and significant for the whole of South Africa, grassland and Nama-Karoo, after controlling for environmental variables. Several sources of environmental heterogeneity, which were shown here to be associated with ecotones, were also found to be important determinants of alien species richness. Main conclusions While most of the current conservation efforts at the regional and global scales are currently directed to distinct ecosystems, our results suggest that much more effort should be directed to the transitions between them, which are small in size and have high native richness, but are also under greater threat from invasive alien species. Understanding how alien species richness and invasibility change across transitions and sharp gradients, where environmental heterogeneity is high, is important for ongoing conservation planning in a biogeographical context

    Cross-boundary collaboration: Key to the conservation puzzle

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    Conservation science is advancing rapidly, yet the majority of research overlooks a key factor that can play a major role in shaping the outcomes of conservation initiatives: collaboration. Here, we review the importance, benefits and limitations of incorporating collaboration into conservation and specifically into systematic conservation planning, providing a general framework for considering collaboration in conservation planning. Recent work shows that cross-boundary collaboration can have both positive and negative impacts on the outcomes of conservation and management efforts for protected areas, ecosystems, threatened and invasive species. The feasibility of collaboration, its likely effects and associated trade-offs should therefore be explicitly incorporated into conservation science and planning. This will ensure that conservation decisions avoid wasted funding when collaboration is infeasible, promoting collaboration when the benefits outweigh the costs

    Emerging conservation challenges and prospects in an era of offshore hydrocarbon exploration and exploitation

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    Globally, extensive marine areas important for biodiversity conservation and ecosystem functioning are undergoing exploration and extraction of oil and natural gas resources. Such operations are expanding to previously inaccessible deep waters and other frontier regions, while conservation-related legislation and planning is often lacking. Conservation challenges arising from offshore hydrocarbon development are wide-ranging. These challenges include threats to ecosystems and marine species from oil spills, negative impacts on native biodiversity from invasive species colonizing drilling infrastructure, and increased political conflicts that can delay conservation actions. With mounting offshore operations, conservationists need to urgently consider some possible opportunities that could be leveraged for conservation. Leveraging options, as part of multi-billion dollar marine hydrocarbon operations, include the use of facilities and costly equipment of the deep and ultra-deep hydrocarbon industry for deep-sea conservation research and monitoring and establishing new conservation research, practice, and monitoring funds and environmental offsetting schemes. The conservation community, including conservation scientists, should become more involved in the earliest planning and exploration phases and remain involved throughout the operations so as to influence decision making and promote continuous monitoring of biodiversity and ecosystems. A prompt response by conservation professionals to offshore oil and gas developments can mitigate impacts of future decisions and actions of the industry and governments. New environmental decision support tools can be used to explicitly incorporate the impacts of hydrocarbon operations on biodiversity into marine spatial and conservation plans and thus allow for optimum trade-offs among multiple objectives, costs, and risks

    Can satellite-based night lights be used for conservation? The case of nesting sea turtles in the Mediterranean

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    Artificial night lights pose a major threat to multiple species. However, this threat is often disregarded in conservation management and action because it is difficult to quantify its effect. Increasing availability of high spatial-resolution satellite images may enable us to better incorporate this threat into future work, particularly in highly modified ecosystems such as the coastal zone. In this study we examine the potential of satellite night light imagery to predict the distribution of the endangered loggerhead (Caretta caretto) and green (Chelonia mydas) sea turtle nests in the eastern Mediterranean coastline. Using remote sensing tools and high resolution data derived from the SAC-C satellite and the International Space Station, we examined the relationship between the long term spatial patterns of sea turtle nests and the intensity of night lights along Israel's entire Mediterranean coastline. We found that sea turtles nests are negatively related to night light intensity and are concentrated in darker sections along the coast. Our resulting GLMs showed that night lights were a significant factor for explaining the distribution of sea turtle nests. Other significant variables included: cliff presence, human population density and infrastructure. This study is one of the first to show that night lights estimated with satellite-based imagery can be used to help explain sea turtle nesting activity at a detailed resolution over large areas. This approach can facilitate the management of species affected by night lights, and will be particularly useful in areas that are inaccessible or where broad-scale prioritization of conservation action is required. Crown Copyright (C) 2012 Published by Elsevier Ltd. All rights reserved

    Testing the relevance of binary, mosaic and continuous landscape conceptualisations to reptiles in regenerating dryland landscapes

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    Context Fauna distributions are assessed using discrete (binary and mosaic) or continuous conceptualisations of the landscape. The value of the information derived from these analyses depends on the relevance of the landscape representation (or model) used to the landscape and fauna of interest. Discrete representations dominate analyses of landscape context in disturbed and regenerating landscapes; however within-patch variation suggests that continuous representations may help explain the distribution of fauna in such landscapes

    Oil spill contamination probability in the southeastern Levantine basin

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    Recent gas discoveries in the eastern Mediterranean Sea led to multiple operations with substantial economic interest, and with them there is a risk of oil spills and their potential environmental impacts. To examine the potential spatial distribution of this threat, we created seasonal maps of the probability of oil spill pollution reaching an area in the Israeli coastal and exclusive economic zones, given knowledge of its initial sources. We performed simulations of virtual oil spills using realistic atmospheric and oceanic conditions. The resulting maps show dominance of the alongshore northerly current, which causes the high probability areas to be stretched parallel to the coast, increasing contamination probability downstream of source points. The seasonal westerly wind forcing determines how wide the high probability areas are, and may also restrict these to a small coastal region near source points. Seasonal variability in probability distribution, oil state, and pollution time is also discussed

    The first Neanderthal remains from an open-air Middle Palaeolithic site in the Levant

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    The late Middle Palaeolithic (MP) settlement patterns in the Levant included the repeated use of caves and open landscape sites. The fossil record shows that two types of hominins occupied the region during this period - Neandertals and Homo sapiens. Until recently, diagnostic fossil remains were found only at cave sites. Because the two populations in this region left similar material cultural remains, it was impossible to attribute any open-air site to either species. In this study, we present newly discovered fossil remains from intact archaeological layers of the open-air site 'Ein Qashish, in northern Israel. The hominin remains represent three individuals: EQH1, a nondiagnostic skull fragment; EQH2, an upper right third molar (RM3); and EQH3, lower limb bones of a young Neandertal male. EQH2 and EQH3 constitute the first diagnostic anatomical remains of Neandertals at an open-air site in the Levant. The optically stimulated luminescence ages suggest that Neandertals repeatedly visited 'Ein Qashish between 70 and 60 ka. The discovery of Neandertals at open-air sites during the late MP reinforces the view that Neandertals were a resilient population in the Levant shortly before Upper Palaeolithic Homo sapiens populated the region
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