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Abstract (from http://link.springer.com/article/10.1007/s11069-016-2376-z): Drought is among the most insidious types of natural disasters and can have devastating economic and human health impacts. This research analyzes the relationship between two readily accessible drought indices—the Palmer Drought Severity Index (PDSI) and Palmer Hydrologic Drought Index (PHDI)—and the damage incurred by such droughts in terms of monetary loss, over the 1975–2010 time period on monthly basis, for five states in the south-central USA. Because drought damage in the Spatial Hazards Events and Losses Database for the United States (SHELDUS™) is reported at the county level, statistical downscaling techniques were used to estimate...
Severe droughts cause widespread tree mortality and decreased growth in forests across the globe. Forest managers are seeking strategies to increase forest resistance (minimizing negative impacts during the drought) and resilience (maximizing recovery rates following drought). Limited experimental evidence suggests that forests with particular structural characteristics have greater capacity to resist change and or recover ecosystem function in the face of drought. However, the applicability of these results to practical forest conservation and management remains unclear. This project utilized an existing network of eight long-term, operational-scale, forest management experiments from Arizona to Maine to examine...
Drought indices are widely used for drought monitoring. This study evaluates the performance of six indices (Palmer’s Drought Severity Index (PDSI), Palmer’s Z-index, precipitation percent normal, precipitation percentiles, Standardized Precipitation Index (SPI), and the Standardized Precipitation Evapotranspiration Index (SPEI)) to determine which are most appropriate for monitoring agricultural drought in the south-central United States. Soil moisture and crop yield data for winter wheat, corn and cotton are used to assess the performance of drought indices. The results indicate that SPEI is the most representative of soil moisture conditions. The best drought index for crop yield varies depending on crop type...
Abstract (from http://www.tandfonline.com/eprint/EBxQ7emIEP3P6pzxz74H/full) Drought is a hazard that inflicts costly damage to agricultural, hydrologic, and ecological systems and affects human health and prosperity. A comprehensive assessment of resilience to the drought hazard in various communities and an identification of the main variables that affect resilience is crucial to coping with the hazard and promoting resilience. This study assessed the community resilience to drought hazards of all 503 counties of Arkansas, Louisiana, New Mexico, Oklahoma, and Texas using the resilience inference measurement (RIM) model for the period of 2000 to 2015. Through k-means cluster analysis, stepwise discriminant analysis...
Volodymyr V. Mihunov, Nina S.N. Lam, Robert V. Rohli, Lei Zou, 2019, Emerging disparities in community resilience to drought hazard in south-central United States, International Journal of Disaster Risk Reduction.
Abstract (from http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0173844): Urban habitats are characterized by impervious surfaces, which increase temperatures and reduce water availability to plants. The effects of these conditions on herbivorous insects are not well understood, but may provide insight into future conditions. Three primary hypotheses have been proposed to explain why multiple herbivorous arthropods are more abundant and damaging in cities, and support has been found for each. First, less complex vegetation may reduce biological control of pests. Second, plant stress can increase plant quality for pests. And third, urban warming can directly increase pest fitness and abundance. These...
The south central U.S. is one of the main agricultural regions in North America and annual agricultural production is valued at more than $44 billion dollars. Climate variability and drought have both direct and indirect impacts on agriculture and consequences for land management. There are many different drought monitoring products and tools available, but unfortunately most were developed without input from the stakeholders who are intended to use them. In the SC CSC region private landowners, such as farmers and ranchers, are responsible for the majority of land management. The goal of this project is to assess the information needs of famers and ranchers in the SC CSC region in the development of drought monitoring...
Abstract (from Natural Hazards): Drought indices are useful for quantifying drought severity and have shown mixed success as an indicator of drought damage and biophysical dryness. While spatial downscaling of drought indicators from the climate divisional level to the county level has been conducted successfully in previous work, little research to date has attempted to “upscale” remotely sensed biophysical indicators to match the downscaled drought indices. This upscaling is important because drought damage and indices are often reported at a coarser scale than the biophysical indicators provide. This research upscales National Oceanic and Atmospheric Administration’s Advanced Very High Resolution Radiometer sensor-acquired...
Abstract (from http://link.springer.com/article/10.1007/s10113-014-0585-0): Drought is a part of the normal climate variability and the life and livelihoods of the Western United States. However, drought can also be a high impact or extreme event in some cases, such as the exceptional 2002 drought that had deleterious impacts across the Western United States. Studies of long-term climate variability along with climate change projections indicate that the Western United States should expect much more severe and extended drought episodes than experienced over the last century when most modern water law and policies were developed, such as the 1922 Colorado River Compact. This paper will discuss research examining...
Categories: Publication; Types: Citation; Tags: Drought, North Central CASC
Abstract (from Ecological Society of America): Tree mortality is an important outcome of many forest fires. Extensive tree injuries from fire may lead directly to mortality, but environmental and biological stressors may also contribute to tree death. However, there is little evidence showing how the combined effects of two common stressors, drought and competition, influence post‐fire mortality. Geographically broad observations of three common western coniferous trees subjected to prescribed fire showed the likelihood of post‐fire mortality was related to intermediate‐term (10 yr) pre‐fire average radial growth, an important component of tree vigor. Path analysis showed that indices of competition and drought...
Abstract (from Ecological Society of America): Predicting vegetation responses to increased future drought is challenging, owing to the complex interaction of multiple factors influencing both plant drought resistance and local climatic conditions, each of which may be subject to spatial and temporal heterogeneity. We conducted a detailed study of potential mechanisms underlying an elevational gradient in mortality that has characterized recent population declines of a threatened alpine plant, the Haleakalā silversword (Argyroxiphium sandwicense subsp. macrocephalum). We used a pair of greenhouse experiments staged at high and low elevations to test the influences of plasticity (to contrasting soil water availability...
Abstract (from http://link.springer.com/article/10.1007/s11258-016-0568-y): Resprouting is a key functional trait for species in disturbance prone environments. In many semi-arid environments, woody plants face both fire and drought as recurring disturbances. Past work has demonstrated that oaks inhabiting sky-island forests of the northern Sierra Madre Oriental have differing microhabitat preferences and heavy stem dieback occured during the historic 2011 drought indicating potential xylem failure. These oak species, representing two sections within the genus, are all post-fire resprouters: they can resprout from underground storage organs when fire kills above ground tissue. Resprouts provide an opportunity to...
Precipitation amounts and frequencies are major regulators of soil heat-load profiles as the interval between rainfall events allows for increased heat storage during cloudless periods. The extreme drought of 2011 and the subsequent Flash Drought that occurred in summer, 2012, developed in part due to soil temperature dynamics across the landscape of the Southern High Plains. The negative impacts of highly variable soil temperatures on ecosystem process can be easily seen in family gardens. Most gardeners across the SHP realize that mulching has a beneficial impact on the success of any gardening effort as mulch reduces the heat storage of the soil thereby providing for a more stable temperature while also reducing...
The responses of individual species to environmental changes can be manifested at multiple levels that range from individual-level (i.e., behavioral responses) to population-level (i.e., demographic) impacts. Major environmental changes that ultimately result in population level impacts are often first detected as individual-level responses. For example, herbivores respond to limited forage availability during drought periods by increasing the duration of foraging periods and expanding home range areas to compensate for the reduction in forage. However, if the individual-level responses are not sufficient to compensate for reduced forage availability, reduced survival and reproductive rates may result. We studied...
Hydrologic extremes of drought and flooding stress water resources and damage communities in the Red River basin, located in the south-central United States. For example, the summer of 2011 was the third driest summer in Oklahoma state history and the driest in Texas state history. When the long-term drought conditions ended in the spring of 2015 as El Niño brought record precipitation to the region, there were also catastrophic floods that caused loss of life and property. Hydrologic extremes such as these have occurred throughout the historical record, but decision-makers need to know how the frequency of these events is expected to vary in a changing climate so that they can mitigate these impacts and losses....
In the southwestern United States, desert mountain ranges are “islands” of forest in a sea of dry grasslands and desert shrubs. It is likely that this region will face a hotter climate in the future. A particular concern is that many of these tree species (oaks, pines, and junipers) are restricted to higher elevations and that a warming climate will reduce the available habitat causing populations to decline. Although all trees are restricted to mountains in this region, different species prefer different local habitats (for example, one might prefer south slopes, others valley bottoms). This suggests that more than simply elevation determines tree habitat. We took detailed measurements of temperature and soil moisture...
The responses of individual species to environmental changes can be manifested at multiple levels that range from individual-level (i.e., behavioral responses) to population-level (i.e., demographic) impacts. Major environmental changes that ultimately result in population level impacts are often first detected as individual-level responses. For example, herbivores respond to limited forage availability during drought periods by increasing the duration of foraging periods and expanding home range areas to compensate for the reduction in forage. However, if the individual-level responses are not sufficient to compensate for reduced forage availability, reduced survival and reproductive rates may result. We studied...
While we collect and monitor soil temperatures within natural and managed ecosystems across the Southern High Plains (SHP), we do not have a clear understanding of how soil temperature parameters are linked to ecosystem services, soil health and sustainability under increasing climate variability and increasing drought severity. Understanding how management decisions will either create positive or negative feedback loops with respect to soil temperature dynamics may be critical for developing sound conservation and soil management practices. As much of the SHP is privately owned and is managed either under intensive row cropping systems, any drought mitigation efforts and practices that influence and promote soil...
Abstract (from http://onlinelibrary.wiley.com/doi/10.1111/gcb.13612/full): Rich fens are common boreal ecosystems with distinct hydrology, biogeochemistry and ecology that influence their carbon (C) balance. We present growing season soil chamber methane emission (FCH4), ecosystem respiration (ER), net ecosystem exchange (NEE) and gross primary production (GPP) fluxes from a 9-years water table manipulation experiment in an Alaskan rich fen. The study included major flood and drought years, where wetting and drying treatments further modified the severity of droughts. Results support previous findings from peatlands that drought causes reduced magnitude of growing season FCH4, GPP and NEE, thus reducing or reversing...