Arid West Research Articles

Black‐Eyed Pea in the High Plains

AbstractBlack‐eyed pea is a pulse crop and a subspecies of cowpea. Historically, most of the black‐eyed pea grown for grain has been in California. As water availability declined in the region, production shifted to Texas in the 1990s and to Arizona in the early 2000s. The pulse‐crop‐producing regions of Nebraska, Kansas, and Colorado have seen an increase in black‐eyed pea acreage over the past nine years as an effort to maintain U.S. production levels. Black‐eyed pea is a suitable cash crop legume to enhance the dryland cropping rotations. What once was a crop grown on irrigated acres in the arid West has been found to flourish on the dryland and limited‐irrigation acres of the High Plains. Earn 0.5 CEUs in Crop Management by reading this article and taking the quiz at https://web.sciencesocieties.org/Learning‐Center/Courses.

Habitat changes in response to pressures in the Verlorenvlei Estuarine Lake, South Africa

Verlorenvlei is a globally important RAMSAR wetland on the arid west coast of South Africa. A prolonged drought between 2016 and 2021 and increasing competition for water from the agricultural sector resulted in extremely low water levels. We used historical aerial and satellite imagery from 1942 and rainfall and water level data for the past 50 years, to assess habitat changes within the estuarine functional zone of the Verlorenvlei Estuarine Lake. Prior to the drought, lake water levels and water surface area remained stable (1113 ± 27 ha (SE)). Since then, there has been a 64% decrease in open water area, exposing 193 ha of sandbanks, of which 190.9 ha were hyper-sulfidic pyrite-rich. The water in the lower lake was hypersaline ( >100), and in the middle, it was acidic (pH<3). The low water level plus sediment and nutrient input from surrounding agriculture resulted in a localised increase in reeds. Additional pressures, such as fires, have reduced the above-ground biomass of reeds and sedges, potentially altering surface morphology and reducing stored carbon. Despite flooding and filling up in June 2023, the lake remained in an acidic state (3.9–4.3). Similar low-lake level, hypersaline and acidic conditions are predicted to become more common under future climate change scenarios where aridity and extreme weather events are anticipated. Inflow of fresh water into the estuary and control of farming practices are required to keep the Verlorenvlei in a functional state, with long-term monitoring necessary to assess the ecological condition in response to restoration actions.

Southern Africa's Great Escarpment as an amphitheater of climate-driven diversification and a buffer against future climate change in bats.

Hosting 1460 plant and 126 vertebrate endemic species, the Great Escarpment (hereafter, Escarpment) forms a semi-circular "amphitheater" of mountains girdling southern Africa from arid west to temperate east. Since arid and temperate biota are usually studied separately, earlier studies overlooked the biogeographical importance of the Escarpment as a whole. Bats disperse more widely than other mammalian taxa, with related species and intraspecific lineages occupying both arid and temperate highlands of the Escarpment, providing an excellent model to address this knowledge gap. We investigated patterns of speciation and micro-endemism from modeled past, present, and future distributions in six clades of southern African bats from three families (Rhinolophidae, Cistugidae, and Vespertilionidae) having different crown ages (Pleistocene to Miocene) and biome affiliations (temperate to arid). We estimated mtDNA relaxed clock dates of key divergence events across the six clades in relation both to biogeographical features and patterns of phenotypic variation in crania, bacula and echolocation calls. In horseshoe bats (Rhinolophidae), both the western and eastern "arms" of the Escarpment have facilitated dispersals from the Afrotropics into southern Africa. Pleistocene and pre-Pleistocene "species pumps" and temperate refugia explained observed patterns of speciation, intraspecific divergence and, in two cases, mtDNA introgression. The Maloti-Drakensberg is a center of micro-endemism for bats, housing three newly described or undescribed species. Vicariance across biogeographic barriers gave rise to 29 micro-endemic species and intraspecific lineages whose distributions were congruent with those identified in other phytogeographic and zoogeographic studies. Although Köppen-Geiger climate models predict a widespread replacement of current temperate ecosystems in southern Africa by tropical or arid ecosystems by 2070-2100, future climate Maxent models for 13 bat species (all but one of those analyzed above) showed minimal range changes in temperate species from the eastern Escarpment by 2070, possibly due to the buffering effect of mountains to climate change.

Thirty years of regional groundwater-quality trend studies in the United States: Major findings and lessons learned

Changes in groundwater quality have been evaluated for more than 2,200 wells in 25 Principal Aquifers in the United States based on repeated decadal sampling (once every 10 years) from 1988 to 2021. The purpose of this study is to identify contaminants with changing concentrations, the locations and magnitude of those changes, the factors driving those changes, the obstacles to interpreting the changes, and approaches to ameliorate those obstacles. Sampling was conducted in 89 networks of 20–30 wells each that represent various geographic regions, aquifer types and land use types. Each network, and the wells that comprise them, are sampled on a rotating basis once every 10 years. Of the 28 constituents evaluated for trends, concentrations of Na, Cl, dissolved solids, SO4, and NO3 exhibited statistically significant increases at the network level more frequently than other constituents. Factors affecting trends in Cl and NO3 are emphasized in this study. Regional patterns show large increases of Cl in urban areas in the Northeast and Midcontinent, where road-deicing salt application rates are 10 to 100 times greater than in other regions of the country, and in semiarid and arid regions of the western United States, where evaporation concentrates solutes in recharge. The largest increases in NO3 were in agricultural areas of the semiarid west, arid west and Pacific regions which are characterized by oxic groundwater, long-term increases in nitrogen fertilizer usage, and high rates of irrigation. However, finding a direct relation between increasing contaminant sources and corresponding groundwater quality response, particularly when sampling once every 10 years, can be complicated by factors such as uncertainty in the timing, mass, and location of contaminant sources, groundwater residence time (recharge date), geochemical conditions in the aquifer that affect contaminant transport, and variability in water quality due to climatic factors such as seasonality and hydrologic conditions. Understanding groundwater residence time allows the changes in groundwater quality to be evaluated in the context of recharge date rather than the sample date. Likewise, information on geochemical characteristics of the aquifer can be helpful for understanding relations between contaminant source inputs and groundwater concentrations. For example, oxic geochemical conditions in the aquifer may allow for conservative transport and accumulation of NO3 in groundwater, whereas reducing environments could favor NO3 degradation. Differences in hydrologic conditions (wetter or drier than average) on the date of sampling could impact the statistical results of sampling at decadal intervals and obscure long-term patterns. Samples collected under substantially different hydrologic conditions can be identified, and high-frequency sampling can improve interpretation of measured results in these cases. Although decadal sampling and associated water-quality interpretations have limitations, repeated, scheduled sampling of thousands of wells over multiple decades has great value for identifying and understanding long-term, regional groundwater-quality trends. Despite these limitations, the concepts presented herein provide options that could be used to interpret trends or changes when sampling over longer timespans, which is less common than trend networks with higher frequency sampling intervals.

Changes in How Climate Forces the Vegetation of Southern Africa

Global climatic changes are altering ecosystem structure and functioning, yet detecting and forecasting such change is difficult. In this study, we use the concept of a phytoclime—a region where climate favours the growth of similar combinations of plant types—to examine how changes in climate forcing may impact on regional vegetation. We use species distribution data to estimate the parameters of a physiological plant growth model for 5006 vascular plant species common to southern Africa. Plant type suitability surfaces are calculated as the average climatic suitability of locations for all species belonging to a plant type. We calculated plant type suitability surfaces for ten different plant types. The resulting surfaces were used to produce a spatial classification of phytoclimes, which we interpret as regions that can climatically support particular plant type combinations. We use the phytoclime definitions and climatologies from five global circulation models (GCMs) simulating three shared economic pathways (SSPs) to forecast how the climatic forcing underlying the phytoclimes will change. Our analyses forecast that change in phytoclime state will be widespread throughout the region. There were, however, substantial differences in the timing of when changes would occur. The central interior of the region was forecast to change earlier than the arid west and southern coast. These differences in timing were driven by differences in the responses of trees, succulents, C3 and C4 grasses to the GCMs forecast aridification of the region’s central interior. Phytoclime modelling provides an indication of the potential of a region’s climate to support different plant types; it thereby provides forecasts of the potential impacts of climate change on regional vegetation structure and functioning.

Taxonomy in the phylogenomic era: species boundaries and phylogenetic relationships among North American ants of theCrematogaster scutellarisgroup (Formicidae: Hymenoptera)

AbstractWe investigate the species-level taxonomy and evolutionary history of Nearctic ants in the Crematogaster scutellaris group (Hymenoptera: Formicidae), drawing on evidence from morphology and UCE (ultraconserved element) phylogenomics. The New World species in this group form a well-supported clade that originated in the Late Miocene (~7.3 Mya) and subsequently diverged into three major lineages: the C. coarctata clade (south-western Nearctic), the C. opaca clade (south-western Nearctic and northern Neotropics) and the C. lineolata clade (eastern Nearctic and Caribbean, with four isolated south-west endemics). We hypothesize trans-Beringian dispersal into the New World, west-to-east movement within North America and restriction of mesophilic species to the east with increasing aridification of the west. The ancestral nesting behaviour of these ants is inferred to be ground-dwelling, and this is still the predominant condition in the arid west, whereas most species in the eastern United States are arboreal. We resurrect from synonymy nine species and describe three new species: C. detecta sp. nov. (from Nevada), C. parapilosa sp. nov. (Florida) and C. vetusta sp. nov. (Arizona). We provide a worker-based key to the 34 species of Crematogaster occurring in America north of Mexico, but emphasize that there are still ongoing taxonomic issues that need to be resolved.

Implementing an Operational Framework to Develop a Streamflow Duration Assessment Method: A Case Study from the Arid West United States.

Streamflow duration information underpins many management decisions. However, hydrologic data are rarely available where needed. Rapid streamflow duration assessment methods (SDAMs) classify reaches based on indicators that are measured in a single brief visit. We evaluated a proposed framework for developing SDAMs to develop an SDAM for the Arid West United States that can classify reaches as perennial, intermittent, or ephemeral. We identified 41 candidate biological, geomorphological, and hydrological indicators of streamflow duration in a literature review, evaluated them for a number of desirable criteria (e.g., defensibility and consistency), and measured 21 of them at 89 reaches with known flow durations. We selected metrics for the SDAM based on their ability to discriminate among flow duration classes in analyses of variance, as well as their importance in a random forest model to predict streamflow duration. This approach resulted in a "beta" SDAM that uses five biological indicators. It could discriminate between ephemeral and non-ephemeral reaches with 81% accuracy, but only 56% accuracy when distinguishing 3 classes. A final method will be developed following expanded data collection. This Arid West study demonstrates the effectiveness of our approach and paves the way for more efficient development of scientifically informed SDAMs.

Producer preferences for drought management strategies in the arid west

AbstractThis study uses choice experiments to assess fresh produce and hay/forage grower preferred drought management strategies, the level of drought at which growers adopt specific management strategies and the level of drought at which they choose to exit farming in the arid west. Results show preferred strategies differ by drought level and across grower groups. Using logit models, we find that fresh produce growers prefer adopting a water-saving technology (cover crops, manure/mulch application, etc.) and hay/forage growers prefer switching to a more efficient irrigation system. Growers would only exit farming in extreme circumstances such as loss of all water resources. Policies aimed at assisting growers with drought adaptation should focus on preferred strategies to ensure effectiveness. Incentives to offset adoption costs are also recommended. Additionally, growers may benefit from information related to productivity changes under various drought management strategies and drought scenarios.

Switchgrass biomass yield and composition and soil quality as affected by treated wastewater irrigation in an arid environment

Freshwater (FW) scarcity as a result of prolonged drought has reduced FW availability to agriculture in the arid west Texas region in order to meet demands from other sectors. Alternatively, there is enormous potential to utilize treated urban wastewater (TWW) for agricultural irrigation. However, the soil salinization potential of TWW is a concern as it can be detrimental to crops and soil quality. Alternative crops that are both less water-intensive and salt-tolerant are therefore needed to sustain this region's agriculture. Switchgrass is a perennial grass that is well adapted to grow on marginal lands and is a novel crop for lignocellulosic bioenergy feedstock. However, its performance when irrigated with TWW on arid soils of far west Texas is largely unknown. This field study evaluated the yield potential and composition of switchgrass biomass as affected by TWW along with soil quality changes, using a split-plot experimental design. Results indicate that biomass yields were not affected by TWW irrigation and there were no significant differences between TWW and FW across years. With respect to biomass composition, cellulose and lignin contents were lower, while ash content was significantly higher in TWW treatment. Theoretical ethanol production was not affected. Soil salinity and sodicity increased overtime but this increase was more prominent under TWW irrigation. However, application of gypsum and sulfur significantly reduced soil sodicity. These results indicate that switchgrass can tolerate soil salinity induced by TWW application and therefore can be successfully grown on these marginal arid soils as a bioenergy feedstock.

Prehispanic Highland Textile Technologies: A View from the First Millennium AD at Hualcayán, Ancash, Peru

The exceptional preservation of perishable artifacts on the arid west coast of the Andes has led to an abundance of knowledge on prehispanic textile production. Yet comparatively little of this knowledge is based on highland examples due to their poor preservation in the moist environment of the Andean sierra. Systematic excavations in 2011–2012 at the archaeological complex of Hualcayán in highland Ancash, Peru, revealed surprisingly well-preserved textiles and cordage from four partially looted machay-style tombs. In this article we provide an overview of textile forms, production techniques, and iconography from a sample of 292 textile and cordage fragments, equaling 20% of Hualcayán's assemblage. This work contributes to a better understanding of ancient Andean weaving in general and interregional interaction during the Early Intermediate period and Middle Horizon (ca. AD 1–1000) in particular. Significantly, we document variability in cotton yarn and a general uniformity in camelid yarn and weaving techniques in the overall sample. These findings, in combination with similarities in weaving techniques and style between coastal examples and Hualcayán's fabrics, suggest a coastal–highland relationship.

Yield response of canola as a biofuel feedstock and soil quality changes under treated urban wastewater irrigation and soil amendment application

Treated urban wastewater (TWW) is seen as a potential alternative for agricultural irrigation in arid west Texas region, due to scarcity of Freshwater (FW) supplies. However, TWW can potentially cause soil salinization and affect soil quality and crop productivity. Therefore, crops that are salt-tolerant and less water-intensive are needed to sustain agriculture in this region. Canola (Brassica napus L.) as an edible oilseed and biodiesel/biofuel crop, is salt-tolerant and relatively less water-intensive than crops that are traditional to this area. This two–year field study evaluated the performance of canola under TWW irrigation in terms of its seed yield potential and seed quality (oil content, oil yield and salt constituents), along with quantifying changes in soil salinity and sodicity. Experimental design included a randomized block split-plot with water quality (FW and TWW) as the main-plot and soil amendment (gypsum + sulfur and no-amendment) as the subplot factor. Results show that TWW application did not significantly affect canola seed yields in any of the two years. On average, seed yields were 1975 kg ha−1 across all treatments and years. Seed oil content, oil yield and mineral constituents were also not affected by TWW irrigation. Nevertheless, average seed oil content was 42 % and oil yield was 849 kg ha−1. Other than the effects on soil salinity and sodicity, Gypsum + Sulfur application did not influence canola seed productivity and quality. Changes in soil salinity and sodicity were more prominent under TWW irrigation but the levels were below the thresholds after two years. Gypsum + Sulfur application significantly reduced soil sodicity, especially in TWW irrigated soils. These results highlight that TWW can be successfully used to grow canola as a biofuel feedstock in this arid region while following appropriate soil management practices to alleviate sodicity hazard of TWW in the long-term.

Response of soil organic carbon and soil health indicators to treated wastewater irrigation in bioenergy sorghum production on an arid soil

AbstractTreated urban wastewater (WW) reuse for crop irrigation is seen as an way to mitigate prolonged drought effects and reduced freshwater (FW) availability for agriculture in arid west Texas. However, the impacts of WW on arid soil health are not clearly understood. This field study evaluated the effects of WW irrigation on soil health indicators including soil organic carbon (SOC), permanganate oxidizable carbon (POXC), mineralizable carbon (MC), and soil protein under bioenergy sorghum production. Water type and gypsum + sulfur application were used as main and subplot factors in a split‐plot experimental design with growth year as a repeated measure. Results across time and soil amendments showed that the SOC of WW‐irrigated soils (3.26 g kg−1) was significantly higher than that of FW‐irrigated soils (2.96 g kg−1). This signifies the positive impact of WW to contribute to soil carbon with no associated priming effects. Wastewater and soil amendment application by themselves did not affect other soil health indicators, given their soil salinization potential. Irrespective of the water type and amendment application, soil POXC significantly increased from 245 to 262 mg kg−1 over time, indicating that a labile pool of C was added to the soil. Soil protein concentrations significantly decreased from 1.31 to 1.23 g kg−1 after 2 years, possibly due to mineralization of organic nitrogen. In conclusion, our results demonstrate that WW application did not adversely affect soil health in the short term. Long‐term studies could provide more insight into the sustained effects of WW irrigation on arid soil health.

The Colorado River Delta and California’s Central Valley are critical regions for many migrating North American landbirds

Abstract Migration is an important component of some species full annual cycle. California’s Central Valley and the Colorado River Delta provide important riparian and wetland habitats for migrating waterbirds in the arid west of North America, but little is known about whether these locations are important at the population level to migrating landbirds. We used eBird Status and Trends abundance data to quantify the importance of the Central Valley and Colorado River Delta to landbirds by estimating the proportion of the breeding population of 112 species that use each site during migration. We found that ~17 million landbirds use the Colorado River Delta in the spring and ~14 million in the fall. Across 4 study regions in the Central Valley, up to ~65 million landbirds migrate through in the spring and up to ~48 million in the fall. In the spring and fall, respectively, up to 37 and up to 30 species had at least 1% of their continental population migrate through the study regions. We also quantified the spatial concentration of each species across latitudinal transects to determine the extent to which study regions were acting as migratory bottlenecks. Landbird abundances were spatially concentrated in study regions 29.4% of all migration weeks, indicating that each study region acts as a migratory bottleneck. This application of eBird data is a powerful approach to quantifying the importance of sites to migrating birds. Our results provide evidence of population-level importance of the Central Valley and Colorado River Delta for many migratory landbirds.

How to Prioritize Voluntary Dietary Modification

Environmentally motivated voluntary diet modifications are the focus of much research and public discourse. Yet the nuanced multi-faceted, multi-dimensional nature of agriculture-earth interactions, and limited public environmental knowledge likely combine to undermine the efficacy of environmentally motivated dietary shifts, squandering limited good will. To counter this, here I devise two related indices for crudely estimating importance of various environmental impacts of alternative dietary choices. Based on the devised indices (which—coarse, simple and inexhaustive—are best viewed as preliminary assessment) I find that in the U.S., soil conservation and water use in the arid west may well dominate the environmental impacts of food, easily eclipsing greenhouse gas emissions, and that of a limited considered subset of possible dietary shifts, replacing beef with tofu, some legumes, and some cereals are the most beneficial modifications.

Exploring the Function of Ion-Exchange Membrane in Membrane Capacitive Deionization via a Fully Coupled Two-Dimensional Process Model

In the arid west, the freshwater supply of many communities is limited, leading to increased interest in tapping brackish water resources. Although reverse osmosis is the most common technology to upgrade saline waters, there is also interest in developing and improving alternative technologies. Here we focus on membrane capacitive deionization (MCDI), which has attracted broad attention as a portable and energy-efficient desalination technology. In this study, a fully coupled two-dimensional MCDI process model capable of capturing transient ion transport and adsorption behaviors was developed to explore the function of the ion-exchange membrane (IEM) and detect MCDI influencing factors via sensitivity analysis. The IEM enhanced desalination by improving the counter-ions’ flux and increased adsorption in electrodes by encouraging retention of ions in electrode macropores. An optimized cycle time was proposed with maximal salt removal efficiency. The usage of the IEM, high applied voltage, and low flow rate were discovered to enhance this maximal salt removal efficiency. IEM properties including water uptake volume fraction, membrane thickness, and fixed charge density had a marginal impact on cycle time and salt removal efficiency within certain limits, while increasing cell length and electrode thickness and decreasing channel thickness and dispersivity significantly improved overall performance.

Vegetation Response to Elevated CO2 Slows Down the Eastward Movement of the 100th Meridian

AbstractThe 100th meridian is a conceptual arid‐humid divide that effectively bisects the continent of the United States into the humid east and arid west. Here, we examine the historical and future shifts of the 100th meridian from atmospheric, hydrologic, and agroecological perspectives. We find that the effective arid‐humid divide regarding vegetation greenness and runoff has been moving toward west with a mean shift of 0.73° (1982–2015) and 2.08° (1961–2010), respectively, suggesting decreased agroecological and hydrologic aridity in the region. For future periods, the agroecological divide shows a persistent westward movement, whereas eastward shifts of the 100th meridian are detected from the atmospheric and hydrologic perspectives. Nevertheless, the eastward movements of the atmospheric and hydrologic divide substantially slow down when the vegetation response to elevated atmospheric CO2 is accounted for. This finding demonstrates that CO2 fertilization on vegetation could largely alleviate the warming‐induced drying tendency around the 100th meridian region.

Geographic patterns and environmental correlates of phylogenetic relatedness and diversity for freshwater fish assemblages in North America

The tropical niche conservatism hypothesis suggests that most groups should be most phylogenetically clustered in cold, dry environments. This idea has been well‐tested in plants and some animal groups, but not for fishes. We assess the geographic patterns of freshwater fish phylogenetic structure and investigate the relationships between these patterns and environmental variables across North America and within two biogeographic realms. Phylogenetic relatedness and diversity of 360 freshwater fish assemblages across North America were quantified with three metrics based on a well‐dated phylogeny, and were related to 15 environmental variables using correlation and regression analyses. Geographically, the data were analyzed for North America as well as for separate biogeographic realms. We found that cold temperatures are the strongest determinant of phylogenetic clustering overall. However, in the arid west, clustering is most pronounced in the driest regions. In eastern North America, phylogenetic clustering increases at higher latitudes, while the reverse is true in western North America. The strongest phylogenetic clustering for freshwater fish assemblages on the continent is found in the most arid, rather than the coldest, climate in North America. Our results highlight that patterns of phylogenetic structure of freshwater fishes in North America are driven by both ecological and evolutionary processes that differ regionally.

Assessing Water Resource Issues Among States in the US South East Region

The US Southeast region is endowed with vast deposits of water resource assets located in numerous states. Considering the growing water use to serve rapidly expanding land uses from agriculture, residential areas, thermoelectric to industrial facilities. Over the years, the demand for water to meet the needs of various sectors in the zone has precipitated increased withdrawals, declining levels in aquifers and sectorial imbalance in the distribution. Accordingly, sectorial imbalance and stress attributed to socio-economic, physical and ecological parameters is now being felt in the areas many considered fully endowed with hydrological assets and less vulnerable to depletion. Beset by the management implications of the trends, various agencies in the zone have stepped up mitigation measures. Notwithstanding the gravity of the challenges and the fact that most studies are still festooned with projected depletion patterns in the US arid West, very little work exists in the literature on the changing patterns in water resource use in the Southeast region using a mix scale model. For that, this research will fill that void by assessing the variabilities in water resource use among some states in the Southeast. With emphasis on the issues, trends, factors, and impacts, the study uses secondary info from major data agencies analyzed by mix scale techniques of descriptive statistics and Geographic Information Systems (GIS) to assess the tendencies. The results point to changes in usage among the sectors in the form of gains and declines, the emergence of hydroelectricity and irrigation as the largest users, the dominance of Florida, regional dependence on surface water sources, evidence of depletion and spatial dispersion of these trends across the states. With these changes attributed to various elements, the paper offered suggestions ranging from water conservation measures, the adoption of efficient polices to the design of a regional hydrological information system.

Contextualizing a Latin American Music Video: Natalia Lafourcade's "Nunca es Suficiente"

Contextualizing a Latin American Music Video:Natalia Lafourcade's "Nunca es Suficiente" Richard Francaviglia Last year, while researching the geographical roots of popular "salsa" music heard throughout Latin America, I encountered a cumbia-influenced version of a song titled "Nunca es Suficiente." I knew that the original version of this love song by Mexican singer-songwriter Natalia Lafourcade was a bit up-tempo, but wondered how it would sound when given an even more lively cumbia treatment. For those unfamiliar with the term cumbia, it is a musical style that features a distinctive Latin American beat and melodic incorporation of percussion, vocals, and other instrumentation. If that definition seems a bit vague, I suggest listening to some songs in that genre, which will give you a good idea of how it sounds and feels. Your first reaction—unless you do not have a pulse—is to embrace the rhythm and almost involuntarily sway to it. Cumbia is one of those musical genres that persuades on two levels: it simultaneously invites one to listen and to dance. That explains why the best way to understand it is to experience it firsthand. Regarding cumbia's geographical origins, there is considerable speculation and disagreement. Most claim it originated in Colombia, while others may simply say "the Caribbean." As to cultural origins, the safest bet is a combination of Indigenous, Spanish, and African—no surprise, since all three cultures have played a major role in the region's history. In fact, some claim that the word cumbia itself derives from African roots, cumbe meaning to dance in several languages in the western part of that continent. Others suggest that it means "to party" in a number of Caribbean dialects. In either case, cumbia involves a physical and even sensual engagement with one's surroundings. As a friend from Panama put it, "With cumbia, you hear and feel the music—which is very liberating." The phenomenal spread of cumbia in Latin America is noteworthy. In a region of tremendous musical diversity—folk music styles as well as more elite musical traditions—this rhythm-driven genre seems to know no borders. [End Page 164] Although cumbia may have originated about three hundred years ago (or more) in one part of Latin America, in more recent years it has become one of the defining aspects of a broader regional cultural identity. There is no question that it has found its way into all of Latin America in the past fifty years or so. As a Pacific Coast-oriented geographer, I've heard it playing on radio, television, and other devices from Baja California way down into South America. In fact, when I first noticed versions of it in 1992, I was in the Pacific port of Guayaquil, Ecuador, and thought its Caribbean quality sounded a bit out of place, but nevertheless very delightful. As I later traveled south along the foothills of the central Andes, cumbia seemed to have caught on there as well. In my most recent studies focusing on South America's arid west coast, I noticed that it had even found a home in string bean-shaped Chile, from locales as remote as the Atacama Desert in the country's far north to its populous heart in the vicinity of Valparaíso and Santiago. From the U.S.-Mexican border to Tierra del Fuego is an impressive geographical range, indeed; moreover, the growing popularity of cumbia in the United States confirms its broad appeal, not only among Latinos but among increasing numbers of gringos as well. That said, I should note that even within Latin America, there appear to be some regional variations in cumbia that may depend on earlier local styles that may also determine its rates of acceptance. To understand more about this, however, one would have to conduct research very quickly, since things are changing so rapidly. I should note that I was not consciously studying music on my trips to Latin America, with my main interest being cultural landscapes. Rather, I've enjoyed listening to it as the soundtrack to which people live their daily and nightly lives. One thing has now become clear to me: cumbia is a...

Cross-scale interactions of socio-hydrological subsystems: examining the frontier of common pool resource governance in Arizona

A critical frontier of water management in the western US is the challenge of cross-scale interactions. It is difficult to establish clear governance boundaries and collectively act when basins are interconnected, surface water and groundwater flows are interrelated, and urban and rural water demands are increasingly affected by regional and international telecoupling. Changing climate, snowpack, and rainfall, peri-urbanization, and shifting economics of rural landscapes further increase sustainable governance challenges. Using a lens of cross-scale interactions drawn from the social-ecological literature, we develop a set of conceptual frames for socio-hydrology that highlight: (1) spatial and temporal mismatches, (2) telecoupled flows, and (3) networked and nested systems. Using the exemplary case of Central Arizona, we explore nesting of the system within the larger western socio-hydrological system (SHS), impacts of changing Colorado River policies, such as the Drought Contingency Plan, and emerging institutional arrangements between the State of Arizona, agricultural communities, and Tribal Nations. We conclude with a set of questions that inform analyses of cross-scale, multi-level governance within social-ecological systems. Without grappling with the dynamics and interconnectedness of SHSs, we cannot sustainably manage water in an increasingly arid West.