Insects and recent climate change Halsch, Christopher A; Shapiro, Arthur M; Fordyce, James A ...
Proceedings of the National Academy of Sciences,
01/2021, Letnik:
118, Številka:
2
Journal Article
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Insects have diversified through more than 450 million y of Earth's changeable climate, yet rapidly shifting patterns of temperature and precipitation now pose novel challenges as they combine with ...decades of other anthropogenic stressors including the conversion and degradation of land. Here, we consider how insects are responding to recent climate change while summarizing the literature on long-term monitoring of insect populations in the context of climatic fluctuations. Results to date suggest that climate change impacts on insects have the potential to be considerable, even when compared with changes in land use. The importance of climate is illustrated with a case study from the butterflies of Northern California, where we find that population declines have been severe in high-elevation areas removed from the most immediate effects of habitat loss. These results shed light on the complexity of montane-adapted insects responding to changing abiotic conditions. We also consider methodological issues that would improve syntheses of results across long-term insect datasets and highlight directions for future empirical work.
Climate change and habitat destruction have been linked to global declines in vertebrate biodiversity, including mammals, amphibians, birds, and fishes. However, invertebrates make up the vast ...majority of global species richness, and the combined effects of climate change and land use on invertebrates remain poorly understood. Here we present 35 years of data on 159 species of butterflies from 10 sites along an elevational gradient spanning 0-2,775 m in a biodiversity hotspot, the Sierra Nevada Mountains of Northern California. Species richness has declined at half of the sites, with the most severe reductions at the lowest elevations, where habitat destruction is greatest. At higher elevations, we observed clear upward shifts in the elevational ranges of species, consistent with the influence of global warming. Taken together, these long-term data reveal the interacting negative effects of human-induced changes on both the climate and habitat available to butterfly species in California. Furthermore, the decline of ruderal, disturbance-associated species indicates that the traditional focus of conservation efforts on more specialized and less dispersive species should be broadened to include entire faunas when estimating and predicting the effects of pervasive Stressors.
We document changes in forest structure between historical (1930s) and contemporary (2000s) surveys of California vegetation through comparisons of tree abundance and size across the state and within ...several ecoregions. Across California, tree density in forested regions increased by 30% between the two time periods, whereas forest biomass in the same regions declined, as indicated by a 19% reduction in basal area. These changes reflect a demographic shift in forest structure: larger trees (>61 cm diameter at breast height) have declined, whereas smaller trees (<30 cm) have increased. Large tree declines were found in all surveyed regions of California, whereas small tree increases were found in every region except the south and central coast. Large tree declines were more severe in areas experiencing greater increases in climaticwater deficit since the 1930s, based on a hydrologic model of water balance for historical climates through the 20th century. Forest composition in California in the last century has also shifted toward increased dominance by oaks relative to pines, a pattern consistent with warming and increased water stress, and also with paleohistoric shifts in vegetation in California over the last 150,000 y.
Protected areas (PAs) are often considered the most important biodiversity conservation areas in national plans, but PAs often do not represent national-scale biodiversity. We evaluate the current ...conservation status of plant biodiversity within current existing PAs, and identify potential additional PAs for South Korea. We modeled species ranges for 2,297 plant species using Multivariate Adaptive Regression Splines and compared the level of mean range representation in South Korea's existing PAs, which comprise 5.7% of the country's mainland area, with an equal-area alternative PA strategy selected with the reserve algorithm Marxan. We also used Marxan to model two additional conservation scenarios that add lands to approach the Aichi Biodiversity Target objectives (17% of the country). Existing PAs in South Korea contain an average of 6.3% of each plant species' range, compared to 5.9% in the modeled equal-area alternative. However, existing PAs primarily represent a high percentage of the ranges for high-elevation and small range size species. The additional PAs scenario that adds lands to the existing PAs covers 14,587.55 km2, and would improve overall plant range representation to a mean of 16.8% of every species' range. The other additional PAs scenario, which selects new PAs from all lands and covers 13,197.35 km2, would improve overall plant range representation to a mean of 13.5%. Even though the additional PAs that includes existing PAs represents higher percentages of species' ranges, it is missing many biodiversity hotspots in non-mountainous areas and the additional PAs without locking in the existing PAs represent almost all species' ranges evenly, including low-elevation ones with larger ranges. Some priority conservation areas we identified are expansions of, or near, existing PAs, especially in northeastern and southern South Korea. However, lowland coastal areas and areas surrounding the capital city, Seoul, are also critical for biodiversity conservation in South Korea.
Climate-change refugia Morelli, Toni Lyn; Barrows, Cameron W; Ramirez, Aaron R ...
Frontiers in ecology and the environment,
06/2020, Letnik:
18, Številka:
5
Journal Article
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Climate-change adaptation focuses on conducting and translating research to minimize the dire impacts of anthropogenic climate change, including threats to biodiversity and human welfare. One ...adaptation strategy is to focus conservation on climate-change refugia (that is, areas relatively buffered from contemporary climate change over time that enable persistence of valued physical, ecological, and sociocultural resources). In this Special Issue, recent methodological and conceptual advances in refugia science will be highlighted. Advances in this emerging subdiscipline are improving scientific understanding and conservation in the face of climate change by considering scale and ecosystem dynamics, and looking beyond climate exposure to sensitivity and adaptive capacity. We propose considering refugia in the context of a multifaceted, long-term, network-based approach, as temporal and spatial gradients of ecological persistence that can act as “slow lanes” rather than areas of stasis. After years of discussion confined primarily to the scientific literature, researchers and resource managers are now working together to put refugia conservation into practice.
The severity of wildfire burns in interior lands of western US ecosystems has been increasing. However, less is known about its coastal mountain ecosystems, especially under extreme weather ...conditions, raising concerns about the vulnerability of these populated areas to catastrophic fires. Here we examine the fine-scale association between burn severity and a suite of environmental drivers including explicit fuel information, weather, climate, and topography, for diverse ecosystems in California's northern coastal mountains. Burn severity was quantified using Relative difference Normalized Burn Ratio from Landsat multispectral imagery during 1984-2017. We found a significant increasing trend in burned areas and severity. During low-precipitation years, areas that burned had much lower fuel moisture and higher climatic water deficit than in wetter years, and the percentage of high-severity areas doubled, especially during the most recent 2012-2016 drought. The random forest (RF) machine learning model achieved overall accuracy of 79% in classifying categories of burn severity. Aspect, slope, fuel type and availability, and temperature were the most important drivers, based on both classification and regression RF models. We further examined the importance of drivers under four climatic conditions: dry vs. wet years, and during two extended drought periods (the 2012-2016 warmer drought vs. the 1987-1992 drought). During warm and dry years, the spatial variability of burn severity was a mixed effect of slope, long-term minimum temperature, fuel amount, and fuel moisture. In contrast, climatic water deficit and short-term weather became dominant factors for fires during wetter years. These results suggest that relative importance of drivers for burn severity in the broader domain of California's northern coastal mountains varied with weather scenarios, especially when exacerbated by warm and extended drought. Our findings highlight the importance of targeting areas with high burn severity risk for fire adaptation and mitigation strategies in a changing climate and intensifying extremes.
Accurate information on the distribution of existing species is crucial to assess regional biodiversity. However, data inventories are insufficient in many areas. We examine the ability of ...Multivariate Adaptive Regression Splines (MARS) multi-response species distribution model to overcome species' data limitations and portray plant species distribution patterns for 199 South Korean plant species. The study models species with two or more observations, examines their contribution to national patterns of species richness, provides a sensitivity analysis of different range threshold cutoff approaches for modeling species' ranges, and presents considerations for species modeling at fine spatial resolution. We ran MARS models for each species and tested four threshold methods to transform occurrence probabilities into presence or absence range maps. Modeled occurrence probabilities were extracted at each species' presence points, and the mean, median, and one standard deviation (SD) calculated to define data-driven thresholds. A maximum sum of sensitivity and specificity threshold was also calculated, and the range maps from the four cutoffs were tested using independent plant survey data. The single SD values were the best threshold tested for minimizing omission errors and limiting species ranges to areas where the associated occurrence data were correctly classed. Eight individual species range maps for rare plant species were identified that are potentially affected by resampling predictor variables to fine spatial scales. We portray spatial patterns of high species richness by assessing the combined range maps from three classes of species: all species, endangered and endemic species, and range-size rarity of all species, which could be used in conservation planning for South Korea. The MARS model is promising for addressing the common problem of few species occurrence records. However, projected species ranges are highly dependent on the threshold and scale criteria, which should be assessed on a per-project basis.
The impacts of climate change traverse administrative borders, which calls for new strategies for forest ecosystem conservation and adaptive management. Despite relatively high biodiversity, the ...temperate forests in East Asia have lacked a comprehensive regional evaluation of potential climate change impacts. Here, we assess the level of climate change exposure of the Temperate Broadleaf and Mixed Forests Biome of East Asia by 2070. These temperate forests occupy 18 ecoregions, five countries, and 102 provinces. We categorize climate change exposure by classifying baseline (1960–1990) climate conditions for the current geographic distribution of five temperate forest types within each ecoregion and within the biome. We then measure the level of change under four future climates: a warmer or a hotter future climate and under reduced emissions (RCP4.5) or with emissions continuing unabated (RCP8.5). By 2070, using the RCP8.5 emission scenario, 24.5–65.7% of these forests enter non-analog or the most marginal 1% of baseline climate conditions. These results reveal the need for extensive transboundary governmental coordination, including forest preservation actions among 51 of 54 provinces that will retain some forest locations in climatically stable or low-risk conditions. Furthermore, among 96 provinces with forests that will be highly exposed, 90 will require transboundary climate change adaptation strategies because these forests span their borders, including the border areas of China, the Russian Federation, and North Korea. The analytical approach of this study could serve as a template for supporting transboundary institutional coordination to address climate change.
Increasing heat in urban areas raises heat-related health risks. Green infrastructure and managing surface albedo can reduce the radiation exposure of pedestrians. However, selecting options among ...various radiant fluxes mitigation strategies is challenging, particularly due to potential interactions among options such as planting vegetation or changing surface albedos. We used a multi-strategies model for determining optimal design combinations for reducing mean radiant temperature (MRT) in urban environments across a range of costs and benefits. The solutions are developed by a non-dominated sorting genetic algorithm II (NSGA II) with a MRT simulator. We selected four MRT reduction strategies: tree planting, grass planting, albedo reduction of building walls, and albedo reduction of sidewalks. Model test results for a simulated street canyon show a wide range of optimal alternative plans considering the combination effects of the four strategies. While previous studies have focused on single options to reduce heat load, we found benefits were higher by using a combination of these strategies, which can provide synergistic benefits. These results provide useful information for decision makers confronting real world problems such as heat related mortality. Thermal-friendly design methods and green infrastructure will help the urban environment become sustainable and improve human health and well-being.
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•Solutions to reduce MRT can be informed by using meta-heuristics.•We evaluated multiple combinations of four options to reduce MRT.•Synergistic combination effects occur when applying strategies together.•The model identifies optimal options that maximize MRT reduction and minimize costs.•These optimal solutions can inform cost-effective planning to reduce mortality.
Empirical studies and habitat suitability modeling project significant shifts in species distributions in response to climate change. Because habitat fragmentation can impede species range shifts, ...wildlife corridors may have increasing importance in enhancing climate resilience for species persistence. While habitat connectivity has been studied for over four decades, the design of connectivity specifically to facilitate species movement in response to climate change is a relatively new challenge. We conducted a systematic review of 116 relevant papers from 1996-2017. Research focused on assessing the utility of habitat connectivity for climate change adaptation by species (N = 29) and modeling and mapping climate-wise connectivity for planning purposes (N = 55). Others addressed fundamental questions of connectivity related to climate adaptation (N = 31). Based on empirical data and computer simulations examining species range shifts in response to climate change at leading edges of current distributions; it is clear that large protected areas connected through linkages, and stepping stones embedded in a permeable matrix promote population persistence and facilitate range expansion. We identified 13 approaches to modeling climate-wise connectivity based on either focal species or landscape structure. When prioritizing areas for connectivity conservation, approaches include focusing on connecting areas of low climate velocity, refugia, climate analogs, or linking current to future suitable habitats. Riparian corridors should be considered in connectivity plans because of their importance as natural movement corridors, climate gradients, and refugia. Guidance is provided on selecting the best methods for connectivity design depending on the objectives, available data, and landscape context. Future research needs to evaluate the functionality of climate-wise connectivity models for facilitating range shifts and compare connectivity outcomes across modeling approaches.
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