Southwestern Kansas Research Articles

Climate-Informed Management of Irrigated Cotton in Western Kansas to Reduce Groundwater Withdrawals

The Ogallala aquifer, underlying eight states from South Dakota to Texas, is practically non-recharging south of Nebraska, and groundwater withdrawals for irrigation have lowered the aquifer in western Kansas. Subsequent well-yield declines encourage deficit irrigation, greater reliance on precipitation, and producing profitable drought-tolerant crops like upland cotton (Gossypium hirsutum (L.)). Our objective was to evaluate deficit irrigated cotton growth, yield, and water productivity (CWP) in northwest, west-central, and southwest Kansas in relation to El Niño southern oscillation (ENSO) phase effects on precipitation and growing season cumulative thermal energy (CGDD). Using the GOSSYM crop growth simulator with actual 1961–2000 location weather records partitioned by the ENSO phase, we modeled crop growth, yield, and evapotranspiration (ET) for irrigation capacities of 2.5, 3.75, and 5.0 mmd−1 and periods of 4, 6, and 8 weeks. Regardless of location, the ENSO phase did not influence CGDD, but precipitation and lint yield decreased significantly in southwest Kansas during La Niña compared with the Neutral and El Niño phases. Simulated lint yields, ET, CWP, and leaf area index (LAI) increased with increasing irrigation capacity despite application duration. Southwestern Kansas producers may use ENSO phase information with deficit irrigation to reduce groundwater withdrawals while preserving desirable cotton yields.

“Sex Out of Boredom”: Key Stakeholders’ Perspectives on Teen Pregnancy Prevention in Emerging Immigrant Latino Rural Communities

Abstract Introduction Teen pregnancy (TP) rates are 1.5 times higher among Latina youth than the United States national average and one-third times higher in rural counties. The Socio-Ecological framework recognizes the myriad of issues that impact TP, including four bidirectional levels of influence on teenagers’ behaviors: macro, community, institutional, and interpersonal levels. We aim to fill critical knowledge gaps regarding the influence of key community stakeholders living in rural, Latino-majority communities shaping Latino/a, immigrant adolescents’ TP-related environments. Methods A purposive sample of 48 key stakeholders was drawn from three rural counties (Finney, Ford, and Seward) in southwestern Kansas from 2016 to 2017; participants completed a brief demographic survey and a semi-structured qualitative interview. Qualitative data analysis followed grounded theory within a Socio-Ecological framework, and we used descriptive statistics to analyze survey data. Results Respondents (N = 48) included 5 public health department staff, 8 community health workers, 8 healthcare workers, 9 community members, and 18 high school/college administrators. The mean age was 43 years (SD = 15.5) and 50% self-identified as Latino/a. Recommendations included developing TP prevention education programs for parents, utilizing ongoing events and familiar venues, and keeping content consistent with local culture and norms. Conclusions Key stakeholders’ perceptions regarding TP are often unaccounted for but play a role in shaping youth’s decision-making environments. Policy Implications This information could inform the development of culturally specific TP prevention interventions, especially considering the controversial politics centered on immigration to the U.S. and its negative impact on the overall health of Immigrant Latinos living in the U.S.

Availability of lesser prairie‐chicken nesting habitat impairs restoration success

AbstractRegional populations of lesser prairie‐chickens (Tympanuchus pallidicinctus) have been declining irregularly since the early 1900s (Jensen et al. 2000). Populations in the Sand Sagebrush Prairie Ecoregion of Kansas and Colorado, USA, have been experiencing declines during the last 2 decades. Ecoregion‐wide declines included the Cimarron and Comanche National Grasslands in southwestern Kansas and southeastern Colorado, respectively, from which lesser prairie‐chickens were nearly extirpated by 2016. In 2014, the United States Department of Agriculture (USDA)–Forest Service created a vegetation management plan to restore lesser prairie‐chicken nesting habitat on the National Grasslands. We used management plan recommendations to evaluate available nesting habitat on National Grasslands and surrounding areas for 394 transmitter‐marked lesser prairie‐chickens translocated to the Sand Sagebrush Prairie Ecoregion during 2016–2019. We found that a small proportion of vegetation measurements met the USDA–Forest Service's 100% visual obstruction guidelines of 25.4 to 38.1 cm (Cimarron: 5.3–21.8% of observations among cover types; Comanche: 1.5–3.0%), and grass species with a high value for nesting were rare (Cimarron: 0.5–20.1% of observations within each cover type; Comanche: 1.5–3.0%). Lesser prairie‐chickens selected for 2 of the 10 National Grasslands' cover types (shrubland state and warm season shortgrass state) during breeding season movements, but only shrubland state was selected for during nesting. Our results indicate that nesting habitat for lesser prairie‐chickens is limited on Cimarron and Comanche National Grasslands. As private grassland was also avoided during nesting, lesser prairie‐chickens in Baca and Morton counties are currently primarily relying on Conservation Reserve Program (CRP) grasslands to meet nesting habitat thresholds (Morton, KS: 17.7% CRP; Baca, CO: 16.6% CRP), which may be insufficient to sustain a viable population. Due to the impermanence of CRP, efforts to sustain local populations are likely to depend on increased improved lesser prairie‐chicken nesting habitat on National Grasslands. Grazing strategies such as rest‐rotation and year‐long deferments may provide opportunities to restore lesser prairie‐chicken habitat on sand sagebrush prairie.

Exploring the influence of Late Mississippian to Middle Pennsylvanian tectonics on sediment transport through detrital zircon geochronology, southwestern Kansas and northwestern Arkansas

This study explores the influence of the Alleghanian-Ouachita-Marathon Orogeny and Ancestral Rocky Mountains (ARM) uplifts on sediment dispersal in the Carboniferous through sandstone compositions and detrital zircon provenance analysis. We focus on Upper Mississippian to Middle Pennsylvanian siliciclastic intervals in two areas: (1) the Hugoton Embayment in southwestern Kansas, where six samples of Upper Mississippian and Lower Pennsylvanian sandstone were collected from two boreholes and (2) the Arkoma Shelf and foreland basin in northwestern Arkansas, where nine samples were collected from Lower through Middle Pennsylvanian outcrops. We report 1544 new concordant ages, 582 ages from Kansas core and 962 ages from Arkansas outcrop samples. UPb age spectra are characterized by major Grenville (900–1300 Ma) and Taconic-Acadian (350–500 Ma) age clusters and minor components of older age groups, suggesting a persistent source in the Appalachians tied to the Alleghanian orogeny. However, by Early Pennsylvanian, the Hugoton Embayment samples see the Appalachian source partially replaced by Yavapai-Mazatzal (1800–1600 Ma) and Granite-Rhyolite (1550–1300 Ma) grains, major components of the local basement, that suggest contributions from nearby ARM uplifts. In contrast, contributions from midcontinent basement sources are limited in the Arkoma Shelf and foreland basin samples. Sandstone composition data are also consistent across all Arkoma Shelf and Upper Mississippian Hugoton Embayment samples; whereas, Lower Pennsylvanian Hugoton samples show increases in feldspar and volcanic lithic grains, consistent with input from local midcontinent age provinces. Comparison with published data suggests a similar change in provenance, from extraregional to local sediment sources, is observed across western Laurentia where ARM deformation was active. Together, new and published data support development of a major transcontinental sediment dispersal system in the Late Mississippian, controlled by Alleghanian orogenesis on the eastern Laurentian margin; however, by the Early Pennsylvanian this system was disrupted by development of the ARM.

Fluctuation of body mass in cotton rats and pocket gophers during the late Cenozoic in the Meade basin of Kansas: possible influence of the Huckleberry Ridge Ash-fall

ABSTRACT Equations estimating body mass were used to depict a near 5-million-year history of size change in pocket gophers and cotton rats from the Meade Basin of southwestern Kansas. Although phyletic size decrease was noted in Sigmodon minor and Geomys minor and size increase in Geomys quinni, no long-term intra-basin size trends were observed. Immediately following the Huckleberry Ridge ash-fall at 2.11 Ma, the small Pliocene cotton rat S. minor became extinct, a large cotton rat entered the basin, two gophers became extinct, and two new ones entered the basin. Assuming the same rodent contingent at the Short Haul locality as at the Aries A site, between deposition of the Borchers and Short Haul assemblages, minimally about 0.12 million years, 40% of the Meade Basin rodent fauna turned over and Microtus dispersed into North America across Beringia. Geochemical environmental proxy data did not identify significant climatic events in the Borchers Badlands Pleistocene sequence; consequently it is possible that a super-eruption from the Yellowstone caldera was at least partly responsible for size shifts in cotton rats and pocket gophers and significant modifications to the Meade Basin rodent community.

Estimation of foot-and-mouth disease windborne transmission risk from USA beef feedlots

Windborne spread of foot-and-mouth disease (FMD) requires specific epidemiological and meteorological conditions, thus modeling the risk of windborne spread involves integrating epidemiological and meteorological models. The objective of this study was to investigate the potential risk of windborne spread of FMD from an infected US feedlot using an integrated modeling approach, and to identify factors that determine this risk.To address this objective, we integrated a within-herd epidemiological model and an advanced atmospheric dispersion model, and calculated infection risk dependent on exposed herd size. A previously developed epidemiological model was used to simulate the spread of FMD through a typical U.S. feedlot, while the National Oceanic and Atmospheric Administration’s (NOAA) HYSPLIT atmospheric dispersion model, which has been validated for FMD modeling, was used to model virus dispersion. Infection risk for exposed herds was calculated as a binomial probability accounting for dose and exposed herd size. We modeled risk of windborne spread from a typical 4000 head feedlot in the U.S. state of Iowa (IA), and a typical 48,000 head feedlot in the U.S. state of Kansas (KS) during winter and summer seasons.The risk of windborne spread of FMD varied based on weather/season conditions, estimated average viral shedding rate per head, size of infected herd, and size of exposed herd. In the baseline Kansas scenario (KS/103/W), the median of the maximum daily risk of infecting a 1000-head exposed herd ranged from 58.16 % at 1 km to 0.78 % at 10 km (Table 4). In the baseline Iowa scenario (IA/103/W), the median of the maximum daily risk of infecting a 1000-head exposed herd ranged from 21.78 % at 1 km to 0.05 % at 10 km (Table 4).The minimum control area recommended by the United States Department of Agriculture (USDA) in an FMD outbreak is 10 km from the infected premise. Our results indicate that significant risk of windborne spread may extend beyond 10 km in certain situations. This is particularly a concern in areas where there are large feedlots in relatively close proximity, such as in southwestern Kansas. Our model may be useful as a research tool in the absence of an outbreak and may help direct surveillance and response efforts in the event of an outbreak.

Seal Properties of the Carbonate Reservoirs in Southwestern Kansas for Geological Co2 Storage

Seal Properties of the Carbonate Reservoirs in Southwestern Kansas for Geological Co2 Storage

Evaluating optimal irrigation for potential yield and economic performance of major crops in southwestern Kansas

The Decision Support System for Agrotechnology Transfer – Cropping System Model was used with an objective to evaluate maize (Zea mays L.), winter wheat (Triticum aestivum L.) and grain sorghum (Sorghum bicolor L. Moench) yield, crop water productivity (CWP) and return after variable cost (RAVC) under different combinations of irrigation interval/capacity and plant available soil water (PASW) thresholds on three soil types in southwestern Kansas. Maize, grain sorghum and winter wheat yields were maximized under irrigation capacity of 4.2–6.3, 3.1–4.2 and 2.5–3.1 mm/d, respectively. The lowest and highest values in the range corresponded to silt loam and fine sand soils, respectively. For maize, maximum RAVC ($630–710/ha) and CWP (25–27 kg/ha/mm) were achieved with a relatively shorter irrigation interval (25 mm/4–8 d). RAVC values for grain sorghum and winter wheat were not substantially affected by irrigation interval. The RAVC for grain sorghum and winter wheat ranged from $150 to $200/ha and $310 to $370/ha, respectively. The CWP of grain sorghum peaked at shorter irrigation interval (25 mm/6–8 d), whereas, high CWP of wheat was simulated even at longer irrigation interval (25 mm/26 d). Overall, for winter wheat and grain sorghum, irrigation strategy for attaining higher RAVC values is different from irrigation strategy for attaining higher yield. Whereas, for maize, irrigation strategy for higher yield is the same as that irrigation strategy for higher RAVC. This study guides producers to identify and prioritize the most suitable irrigation strategy for optimizing yield, CWP and/or income while enhancing sustainability of environment and management of ground water. The present work assumes all factors except water are optimal and findings are sensitive to dynamics of price changes, productivity levels and variations in crop management and climate.

SARS-COV-2 and biomimetics: What saves the planet will save our health.

SARS-COV-2 and biomimetics: What saves the planet will save our health.

Detrital Zircon Geochronologic Constraints on Patterns and Drivers of Continental‐Scale Sediment Dispersal in the Late Mississippian

AbstractThe Late Mississippian was a critical time interval in Laurentia's history, marking the transition from carbonate deposition on a stable platform, during the Early to Middle Mississippian, to extensive clastic deposition in the Pennsylvanian to Permian associated with the Laurentia‐Gondwana collision. In the U.S. midcontinent, Chesterian incised valley fill (IVF) systems that developed within a carbonate‐dominated platform provide new insights on the patterns and drivers of continental‐scale sediment dispersal during this transitional period. Here we report 1,037 new concordant detrital zircon U‐Pb ages from nine samples of Uppper Mississippian sandstone collected from cores in southwestern Kansas and from outcrops in northwestern Arkansas. The sandstones are characterized by major age clusters corresponding to the Grenville (900–1,300 Ma) and Taconic‐Acadian (350–500 Ma) orogenies and minor older age groups, suggesting derivation from the Appalachian region. A compilation of published detrital zircon ages from Early Paleozoic sandstones as well as from temporally equivalent units across North America, including from the Appalachian Foreland Basin, Illinois Basin, Arkoma Shelf, Ozark Dome, Black Warrior Basin, and Grand Canyon, suggests Chesterian sandstone age distributions are distinct from those of older sandstones and are consistent with a change to a dominantly Appalachian age signature that was roughly synchronous across the continent. Together, the new and compiled ages support development of a generally E‐W transcontinental sediment dispersal system in the Late Mississippian that was likely controlled by orogenesis on the eastern Laurentian margin, while local variations in the age signatures appear to be controlled by N‐S drainage networks, influenced by glacioeustatic fluctuations and local structures.

Correlation of Pliocene and Pleistocene fossil assemblages from the central and eastern United States: toward a continental rodent biochronology

ABSTRACT The ubiquitous presence and rapid evolution of rodents lend this group to the development of a correlational scheme for United States Cenozoic continental fossil deposits, equivalent to the later Cenozoic section of European MN zones. Expanding on earlier work in the Meade Basin of southwestern Kansas and Florida, Pliocene and Pleistocene mammal assemblages from the northern and southern Great Plains and the eastern United States are correlated based on rodent biostratigraphy. Eleven rodent zones (RZs) are constructed for the last 5 million years based on a new database including all rodent species assemblages during the study period. In addition to the 11 refined RZs that aid in temporal sequencing of unknown rodent assemblages, three broader biozones are recognised, including an early period characterised by the Promimomys immigration event and Hemphillian holdovers, a longer, relatively warm Pliocene to early Pleistocene period dominated by primitive cricetids and archaic arvicolids, and a final zone spanning the last two million years defined by the immigration and radiation of hypselodont Microtus and large, dentally advanced species of the cotton rat, Sigmodon. Modern rodent communities are established in the later part of Biozone 3, between about 0.6–0.3 Ma.

When Bilingualism is the Common Factor: Switch Reference at the Junction of Competence and Performance in Both Second Language and Heritage Language Performance

In this paper we take a closer look at the oft-touted divide between heritage language speakers and adult second language (L2) learners. Here, we explore whether some properties of language may display general effects across different populations of bilinguals, explaining, at least partially, why these two groups show some common differences when compared with monolinguals. To test this hypothesis, we adduce data from two unique populations of bilinguals: a moribund variety of heritage German spoken in southwestern Kansas (Moundridge Schweitzer German) and L2 adult learners of Spanish. Empirically, we investigate whether the confound of switch reference adds an additional cognitive burden to these bilinguals in licensing object control predicates in the former and referential subject pronouns in the latter. Our preliminary findings support the view that overarching concepts such as incomplete acquisition cannot capture the variability observed in these populations, thus further supporting approaches that interpret findings such as these to be the result of specific variables.

Discovery of the Arkansas Darter (Etheostoma cragini) in the Cow Creek Watershed, Cherokee County, Southeastern Kansas

The Arkansas Darter (Etheostoma cragini) is a threatened species in Kansas and was a candidate for threatened status under the Endangered Species Act (1973). The Arkansas Darter's distribution in Kansas includes the Cimarron River basin of southwestern Kansas, the Arkansas River basin in southcentral Kansas, and the Spring River basin (SRB) in southeastern Kansas. Historical surveys in the SRB during the 1960s and 1990s did not detect the Arkansas Darter in the Cow Creek watershed, which is the northernmost tributary of the Spring River. Here we report detection of the Arkansas Darter in three streams of the Cow Creek watershed during August and September 2017, including an unnamed tributary of Cow Creek (eight individuals), the Cow Creek mainstem (one individual), and the Long Branch (five individuals). Although Arkansas Darters were detected in three different streams, collections were all within 1.5 river kilometers of one another. Further, the species was not detected at 26 other locations in the Cow Creek watershed during 2017, indicating a restricted distribution for this fish in this system. This range extension for the Arkansas Darter in the SRB of Kansas may have conservation implications.

Understanding the Impact of Radar and In Situ Observations on the Prediction of a Nocturnal Convection Initiation Event on 25 June 2013 Using an Ensemble-Based Multiscale Data Assimilation System

The initiation of new convection at night in the Great Plains contributes to a nocturnal maximum in precipitation and produces localized heavy rainfall and severe weather hazards in the region. Although previous work has evaluated numerical model forecasts and data assimilation (DA) impacts for convection initiation (CI), most previous studies focused only on convection that initiates during the afternoon and not explicitly on nocturnal thunderstorms. In this study, we investigate the impact of assimilating in situ and radar observations for a nocturnal CI event on 25 June 2013 using an ensemble-based DA and forecast system. Results in this study show that a successful CI forecast resulted only when assimilating conventional in situ observations on the inner, convection-allowing domain. Assimilating in situ observations strengthened preexisting convection in southwestern Kansas by enhancing buoyancy and locally strengthening low-level convergence. The enhanced convection produced a cold pool that, together with increased convergence along the northwestern low-level jet (LLJ) terminus near the region of CI, was an important mechanism for lifting parcels to their level of free convection. Gravity waves were also produced atop the cold pool that provided further elevated ascent. Assimilating radar observations further improved the forecast by suppressing spurious convection and reducing the number of ensemble members that produced CI along a spurious outflow boundary. The fact that the successful CI forecasts resulted only when the in situ observations were assimilated suggests that accurately capturing the preconvective environment and specific mesoscale features is especially important for nocturnal CI forecasts.

New specimens of Pliocene bats (Mammalia, Chiroptera, Vespertilionidae and Molossidae) from the Meade Basin, Kansas, U.S.A.

ABSTRACTNew Pliocene bat records from the Meade Basin of southwestern Kansas increase our knowledge of chiropterans from the late Neogene of the central Great Plains. Examination of previously collected, unstudied material and new specimens recovered over the past 20 years resulted in 23 fossils of Pliocene bats from nine localities that add to the two Pliocene specimens previously known from the area. All are from the early Blancan North American Land Mammal Age. Two families and at least five species were identified: Molossidae, represented by a Tadarida, and Vespertilionidae by Lasiurus fossilis, Perimyotis cf. subflavus, Nycticeius cf. humeralis, Eptesicus cf. fuscus, and several vespertilionids of indeterminate genera. Lasiurus fossilis is the only extinct species and is shown to be a member of the subgenus Lasiurus, diagnosed by the unique combination of a small P3 and a two-rooted p4. Most of the Meade Basin Pliocene bats probably roosted in trees, although the Perimyotis during hibernation and the molossid may have roosted in rock crevices or possibly gypsum karst features. These results affirm that the modern bat fauna of the central Great Plains had largely been established at the generic level by the Pliocene.Citation for this article: Czaplewski, N. J., G. S. Morgan, and R. A. Martin. 2018. New specimens of Pliocene bats (Mammalia, Chiroptera, Vespertilionidae and Molossidae) from the Meade Basin, Kansas, U.S.A. Journal of Vertebrate Paleontology. DOI: 10.1080/02724634.2018.1430034.

High-resolution techno–ecological modelling of a bioenergy landscape to identify climate mitigation opportunities in cellulosic ethanol production

Although dedicated energy crops will probably be an important feedstock for future cellulosic bioenergy production, it is unknown how they can best be integrated into existing agricultural systems. Here we use the DayCent ecosystem model to simulate various scenarios for growing switchgrass in the heterogeneous landscape that surrounds a commercial-scale cellulosic ethanol biorefinery in southwestern Kansas, and quantify the associated fuel production costs and lifecycle greenhouse gas (GHG) emissions. We show that the GHG footprint of ethanol production can be reduced by up to 22 g of CO2 equivalent per megajoule (CO2e MJ–1) through careful optimization of the soils cultivated and corresponding fertilizer application rates (the US Renewable Fuel Standard requires a 56 gCO2e MJ−1 lifecycle emissions reduction for ‘cellulosic’ biofuels compared with conventional gasoline). This improved climate performance is realizable at modest additional costs, less than the current value of low-carbon fuel incentives. We also demonstrate that existing subsidized switchgrass plantings within this landscape probably achieve suboptimal GHG mitigation, as would landscape designs that strictly minimize the biomass collection radius or target certain marginal lands.

Derivational complexity vs. transfer effects

Abstract We investigate whether non-target wh-questions in heritage Low German and L2 English speakers are due primarily to cross-linguistic transfer or the reduction of grammatical complexity in developing grammars as modelled by the Derivational Complexity Hypothesis (DCH, Jakubowicz 2005). Previous research shows that complex (i.e. cross-clausal) wh-dependencies pose more difficulty to child L1 and adult L2 learners than monoclausal dependencies (Jakubowicz & Strik, 2008; Schulz, 2011; Slavkov, 2015). To avoid complex dependencies, learners often use medial constructions where the wh-item surfaces once at the left periphery of the embedded CP and a second time at the left periphery of the matrix clause. Medial-wh is ungrammatical in English, though possible in German and its varieties, e.g. the low German Plautdietsch. In this study, we investigate the linguistic behavior of twelve (n = 12) bilingual Plautdietsch-English speakers in Southwestern Kansas, analyzing their production and judgments of wh-questions in both languages. In production and judgment tasks, we find that, in the L1, only heritage speakers produced medial-wh, while in L2 English, only late L2 learners produced medial-wh. This pattern cannot be due to transfer, since speakers produce medial-wh in only one of their languages. Instead, medial-wh surfaces as a mechanism to reduce syntactic complexity in the less dominant language, irrespective of whether it is the L1 or the L2 or whether it was acquired early or late. We argue that the DCH can account for grammatical restructuring in both heritage L1 speakers and late L2 speakers and discuss its potential as a metric of incomplete acquisition and attrition in bilingual syntax.

Planting Geometry Effects on the Growth and Yield of Dryland Cotton

The declining Ogallala Aquifer beneath the Southern High Plains may necessitate dryland crop production and cotton (Gossypium hirsutum L.) is a well-adapted and potentially profitable alternative crop. The limited growing season duration of the Texas Panhandle and southwestern Kansas, however, imposes significant production risk due to incomplete boll maturation. Emphasizing earlier boll production that is usually confined to sites on lower fruiting branches may reduce risk, but offsetting high planting densities are needed to maintain desirable lint yield. Our objectives were to quantify planting: 1) row width and 2) in-row spacing effects on growth, yield, and fiber quality of dryland cotton. Field tests of row widths from 0.25 to 0.76 m and plant densities with in-row spacing ranging from 0.075 to 0.15 m were conducted from 1999 to 2005 on a nearly level Pullman clay loam (fine, mixed, superactive, thermic Torrertic Paleustoll) managed in a wheat (Triticum aestivum L.), cotton, fallow (W-Ctn-F) rotation. To expand the basis of comparison, cotton growth and yields were simulated using GOSSYM and long-term (1958-2000) weather records from Bushland, TX, as input for all combinations of 0.38 or 0.76 m row widths and plant spacing of 0.075, 0.10 and 0.15 m. Experimental and computer simulated plant height and harvested boll number increased significantly with increased row spacing and, occasionally, in-row plant spacing. Modeled lint yield for 0.38 m rows decreased by approximately 50% compared with the 582 kg·ha-1 yield for conventional row spacing, which was practically duplicated by field observations in 2001 and 2004. Measured fiber quality occasionally improved with conventional row spacing over ultra-narrow rows, but was unaffected by plant spacing. Because narrow rows and frequent plant spacing did not improve lint yield or fiber quality of dryland cotton, we do not recommend this strategy to overcome a thermally limited growing season.

Conserving the Ogallala Aquifer in southwestern Kansas: from the wells to people, a holistic coupled natural–human model

Abstract. The impact of water policy on conserving the Ogallala Aquifer in Groundwater Management District 3 (GMD3) in southwestern Kansas is analyzed using a system-level theoretical approach integrating agricultural water and land use patterns, changing climate, economic trends, and population dynamics. In so doing, we (1) model the current hyper-extractive coupled natural–human (CNH) system, (2) forecast outcomes of policy scenarios transitioning the current groundwater-based economic system toward more sustainable paths for the social, economic, and natural components of the integrated system, and (3) develop public policy options for enhanced conservation while minimizing the economic costs for the region's communities. The findings corroborate previous studies showing that conservation often leads initially to an expansion of irrigation activities. However, we also find that the expanded presence of irrigated acreage reduces the impact of an increasingly drier climate on the region's economy and creates greater long-term stability in the farming sector along with increased employment and population in the region. On the negative side, conservation lowers the net present value of farmers' current investments and there is not a policy scenario that achieves a truly sustainable solution as defined by Peter H. Gleick. This study reinforces the salience of interdisciplinary linked CNH models to provide policy prescriptions to untangle and address significant environmental policy issues.

Regeneration and invasion of cottonwood riparian forest following wildfire

Populus deltoides is considered to be a weak resprouter and highly susceptible to wildfire, but few post‐wildfire studies have tracked P. deltoides response and resprouting within the Great Plains of North America. Following a wildfire in southwestern Kansas, U.S.A., we surveyed burned and unburned areas of a cottonwood riparian forest along the Cimarron River that included a major understory invader, tamarisk (Tamarix ramosissima Ledeb.). We tested the following hypotheses, which are consistent with the current understanding of P. deltoides response to wildfire in the Great Plains: (1) regeneration of P. deltoides will be low in areas burned by the wildfire; (2) the number of dead P. deltoides individuals will be greater in the wildfire than unburned areas; and (3) tamarisk regeneration will be higher than P. deltoides regeneration in the wildfire areas because tamarisk is considered a stronger resprouter. We found evidence contrary to two of our hypotheses 3 years following the wildfire. (1) P. deltoides regeneration was high following the wildfire, averaging 692 individuals/ha. (2) The number of dead mature cottonwood trees was greater in wildfire plots than in unburned plots. (3) There was more P. deltoides regeneration than tamarisk regeneration following wildfire. These findings, which diverge from the majority of studies examining P. deltoides regeneration in the Great Plains, suggest that differing local environmental and forest stand conditions, coupled with the timing and intensity of the fire, could be important determinants of riparian forest species' responses to wildfire.