Scott D. Bassett

Placing the 2012–2015 California-Nevada drought into a paleoclimatic context: Insights from Walker Lake, California-Nevada, USA

Assessing regional hydrologic responses to past climate changes can offer a guide for how water resources might respond to ongoing and future climate change. Here we employed a coupled water balance and lake evaporation model to examine Walker Lake behaviors during the Medieval Climate Anomaly (MCA), a time of documented hydroclimatic extremes. Together, a 14C-based shoreline elevation chronology, submerged subfossil tree stumps in the West Walker River, and regional paleoproxy evidence indicate a ~50 year pluvial episode that bridged two 140+ year droughts. We developed estimates of MCA climates to examine the transient lake behavior and evaluate watershed responses to climate change. Our findings suggest the importance of decadal climate persistence to elicit large lake-level fluctuations. We also simulated the current 2012–2015 California-Nevada drought and found that the current drought exceeds MCA droughts in mean severity but not duration.

Predictive Soil Maps Based on Geomorphic Mapping, Remote Sensing, and Soil Databases in the Desert Southwest

We present an expert based system to rapidly predict the shallow soil attributes that control dust emissions in the arid southwest U.S. Our system’s framework integrates geomorphic mapping, remote sensing, and the assignment of soil properties to geomorphic map units using a soil database within a geographic information systems (GIS) framework. This expert based system is based on soil state factor-forming model parameters that include: (1) climate data, (2) landform, (3) parent material, and (4) soil age. The four soil-forming data layers are integrated together to query the soil database. To validate the accuracy of the expert based model and resultant predictive soil map, a blind test was performed at Cadiz Valley in the Mojave Desert, California. The desert terrain in Cadiz Valley consists of alluvial fans, fan remnants, sand dunes, and playa features. The test began with three users independently mapping an area of over 335 km2 using 1:40,000-scale base maps to rapidly create geomorphic and age class layers, and then integrating these with climate and parent material layers. The results of the four data layers were then queried in the soil data base and soil attributes assigned to map unit layers. The soil-forming model presented here is geomorphic-based, and considers soil age as a significant factor in accurately predicting soil conditions in hyper arid to mildly arid regions. This work comprises a successful first step in the development of an expert-based system to map shallow soil conditions in support of dust emission models in remote desert regions.

Distribution and Recovery Of Vegetational Assemblages In Ash Meadows National Wildlife Refuge, Nevada

Abstract Ash Meadows National Wildlife Refuge, Nye Co., Nevada, is a small oasis in the northern Mojave Desert. Changes in use of land through irrigated agriculture and associated pumping of groundwater, as well as mining peat moss, altered the environment prior to its designation as a refuge in 1984. We evaluated relationships between land use, land cover, and groundwater in Ash Meadows National Wildlife Refuge from 1948 to 2004. Recovery of land cover was documented following cessation of agricultural activities and pumping of groundwater. Land-use activities from 1948 to 1980 reduced land cover by 1,141 ha, while later changes in land-use activities allowed recovery of 935 ha of land cover. Limited change in groundwater might have aided in recovery of land cover, although no relationship was established between depth-to-groundwater and land cover.

Impact of urban structure on avian diversity along the Truckee River, USA

Urban riparian habitats are potentially important resources for native birds in arid ecosystems. Most studies have assessed the value of urban riparian habitat in terms of vegetation and natural resources; however, the surrounding land use and infrastructure may determine the viability of urban habitat. We studied the impact of urban structure, the combination of land use, infrastructure and vegetation variables that work together to shape the urban environment, on avian riparian habitat in the Truckee Meadows, Nevada, USA. Land use and infrastructure explained avian species richness and abundance better than local vegetation alone, but community resemblance was more strongly correlated to vegetation. Avian species guilds responded differentially to surrounding land use, suggesting there may be a functional difference between land use types. The best models for bird diversity used urban structure (both land use and vegetation) to describe potential habitat. Urban structure describes urban habitat in ways that vegetation variables alone cannot. Studies that ignore land use and infrastructure and other socioeconomic variables are likely missing key functional differences within urban ecosystems, and may miss the potential for compatible development that encourages both biodiversity and urban growth.

Raptor nesting locations along an urban density gradient in the Great Basin, USA

Raptors are the most prevalent group of urban apex predators, and the majority of raptor genera in North America have been recorded using urban areas. Prior research assessments along urban-wildland gradients show that urban habitat preference varies by raptor species and that raptor nesting preferences within urban settings may vary. Attempts to understand the intra- and inter-specific nesting patterns along an urban gradient would advance extant knowledge. Here we present the locations of individual nest sites of nine raptor species along an urban gradient in Reno-Sparks, NV. We developed an urban density model based on the number of residents, number of employees, and building footprints and number of floors for built structures within each land parcel at four spatial scales, representing nest site, macrohabitat, average nearest-nest, and landscape scales. Cooper’s Hawks (Accipiter cooperii), Sharp-shinned Hawks (Accipiter striatus), and Red-tailed Hawks (Buteo jamaicensis) nested across the widest range of the urban spectrum and closest to the urban core, whereas Golden Eagles (Aquila chrysaetos) and Swainson’s Hawks (Buteo swainsonii) nested on the urban fringe. Urban density for all nest locations was lowest at the nest-site scale, and the highest at the average nearest-nest and landscape scales. Raptors tended to occupy a wide range of the building-area density spectrum but not the building-height or employee density spectrums indicative of the attractiveness of suburban habitat.

Developing alternative land-use scenarios to facilitate natural resource management across jurisdictional boundaries

Scenario planning is an effective approach for examining possible futures by exploring the implications and consequences of different policy responses to landscape stressors. We present here a case study that explores plausible futures of urban growth in Southern Nevada, USA that illustrates how scenario analysis can be used to inform region-wide resource management by spatially modeling drivers of change, resource impacts, and potential policy responses. Using a suite of energy, water and biodiversity impact models, we assess the outcomes of the various futures on priority resources, resulting in a clear basis of comparison between alternative policies and their potential outcomes. This case study demonstrates the utility of scenario modeling for natural resource management by exploring crucial policy decisions that might be made in the near-term that could have lasting and sometimes conflicting influences on regional resources over the long term.

Integrated Terrain Forecasting for Military Operations in Deserts: Geologic Basis for Rapid Predictive Mapping of Soils and Terrain Features

During the past three decades, the U.S. armed forces have been called on repeatedly to operate in the deserts of the Middle East and southwest Asia. Avoiding locations susceptible to extreme dust emissions and other terrain-related hazards requires the ability to predict soil and terrain conditions, often from limited information and under dynamic environmental conditions. This paper reports the approach used to develop an integrated, predictive tool for forecasting terrain conditions to support military operations in desert environments at strategic, operational, and tactical scales. The technical approach relies on the systematic integration of desert landform parameters in geomorphic models for predicting terrain conditions. This integrated effort is performed in a geographic information system (GIS) framework using expert-based analysis of airborne and spaceborne imagery to identify terrain elements. Advances in earth science research have established that unique, predictable relations exist among landscape position, soils, vegetation, and geology. Furthermore, new instrumentation allows the collection of a wide range of environmental information to characterize surface and subsurface conditions. By integrating models and methods from geomorphology, soil science, climatology, and atmospheric science with remote sensing and other technologies, a predictive model can be developed to support military operations.

Book Review: Water and the City: Risk, Resilience and Planning for a Sustainable Future

Throughout the book, there are some ideas about planning here and there, although Kahneman does not address planning directly. For example, in comparing a pair of choice problems with sure gain and loss in relation to probabilistic combinations of gain and loss, Kahneman distinguishes narrow from broad framing. When looking at a pair of choices separately (i.e., narrow framing), the subjects tended to make the choices that were inferior to those when the pair of choices were considered together (i.e., broad framing). I argue that the implications in the planning context are twofold. On one hand, this particular experiment shows that making single decisions separately results in an outcome that is different from that of making interdependent decisions. On the other hand, making interdependent decisions may yield an outcome that is better than that derived from making single decisions. Making interdependent decisions is a special feature of plan making and normally yields better outcomes than those of making single decisions independently (Hopkins 2001, 58–64). Kahneman does, however, address planning to some extent by noting the planning fallacy. He and Amos Tversky “term planning fallacy to describe plans and forecasts that are unrealistically close to best-case scenarios” and “could be improved by consulting the statistics of similar cases” (p. 250). Kahneman then continues to argue that examples of the planning fallacy abound in the experiences of individuals, governments, and businesses by providing some true stories in the real world. The planning fallacy occurs when the decision maker focuses on the inside view of a project that depends solely on the decision maker’s own experiences, without realizing that the outside view exists that takes into account a sample of similar situations in the world. Thus, Kahneman suggests ways of mitigating the planning fallacy by citing Bent Flyvbjerg’s (2006) work to adopt distributional information in making plans and forecasts of projects. Kahneman spends a significant number of pages depicting and justifying the heuristics on which people depend to make probabilistic choices. I believe that if the formulation of plans itself is a decision-making problem, then these explanations and justifications of heuristics can and should be readily applied to explain planning behavior. According to Kahneman, a heuristic is a simple mental procedure that helps find adequate, albeit imperfect, answers to difficult questions. In particular, people tend to substitute a simple question for a more difficult one in finding answers of probabilistic judgments, thus resulting biases. For example, a more difficult question of “How much would you contribute to save an endangered species?” would be replaced by an easier one of “How much emotion do I feel when I think of dying dolphins?” The answer to the second question apparently does not address the first question. In the urban planning context, the first question asks for the valuation of some type of natural resource while the second question might prompt the decision maker’s feeling for saving that resource, resulting in a psychological judgment completely different from the true valuation. Numerous analogies can be derived directly and indirectly from Kahneman’s arguments for debiasing heuristic judgments in the planning context. The scope of planning research can be very wide, and planning logic can be explained from narrow and broad viewpoints. From the narrow point of view, the logic is a set of axioms describing how plans should be made, whereas from the broad point of view, it is a set of explanations about planning phenomena. The behavioral planning theory proposed here belongs to the narrow viewpoint of planning logic, that is, it explores how plans should be and are actually made. Even within the narrow definition of plans, there remain many interesting research topics worth pursuing. I have slighted some preliminary ideas about how to proceed to constructing such a theory. I believe that academic planners can learn many lessons from Kahneman’s work in understanding the behavioral aspects of planning behavior. Much work remains to be done in the future.