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Prior to this study, there was no information on arthropods, bats, and other vertebrates of caves in northwesternmost Arizona. Based on invertebrate and vertebrate inventory work conducted during 2005 and 2006, we provide future directions for conservation and management for caves on Grand Canyon—Parashant National Monument, northwestern Arizona. Baseline investigations to find and identify arthropods, bats, and other vertebrates were conducted at 7 of the largest known caves on the monument. We identified 52 morphospecies including 44 arthropods, 4 bats, and 4 other vertebrates. Of the cave-dwelling arthropods, we found 10 eisodophiles, 6 troglophiles, 8 questionable troglophiles, 7 trogloxenes, 8 accidentals, 3 taxa of unknown cave affiliations, and 2 mammalian parasites. We made several contributions to the entomological record including 2 new genera, 6 new species, 3 possible new species, one range extension, and one possible range extension. Also, we identified 5 bat roosts—1 hibernaculum, 2 night roosts, and 3 summer roosts of unconfirmed use. Observed arthropod richness per cave ranged from 1 to 14 morphospecies, and observed bat and other vertebrate (combined) richness was 1–3 morphospecies. We did not detect any cave-adapted arthropods during this investigation. For the caves sampled, we are uncertain whether the lack of cave-adapted taxa is due to (a) low nutrient input and high cryptoaridity associated with many southwestern cave systems or (b) lack of intensive sampling. Despite the lack of cave-adapted species, 5 of the 7 caves inventoried are considered of high management concern. Additional research at these caves will be required to obtain the data necessary to best manage and protect these systems.
We used sequences from the mitochondrial control region to examine the phylogeography and historical demography of the Scaled Quail and to determine whether the geographic distributions of mtDNA genealogy were concordant with the distribution of the subspecies. Overall, the Scaled Quail exhibited lower haplotype and nucleotide diversity than other quail species. The highest levels of haplotype diversity were found in 3 Texas counties: Dimmit, La Salle, and Hudspeth. The Scaled Quail exhibited no phylogeographic structure among its 16 haplotypes, and the patterns of genetic variation were not congruent with potential geographic barriers or current subspecies taxonomy. The geographic distribution of haplotypes and partitioning of molecular variation suggested slight genetic differentiation between the chestnut-bellied subspecies of Scaled Quail and the 3 western subspecies. The low levels of genetic diversity and the evidence of demographic expansion suggest that the Scaled Quail has undergone population and range expansion from a Pleistocene refugium. The greater genetic diversity within the Chestnut-bellied Quail may indicate the geographic location of the refugium.
Successfully managing wetlands requires monitoring changes in plant community composition. We used remote sensing techniques to document the replacement of desirable native wetland vegetation with invasive species in response to catastrophic flood disturbance in the 1980s and to evaluate wetland vegetation management between 1998 and 2010. We conducted our study at the Bear River Migrator Bird Refuge wetlands, which are located on the northeastern arm of the Great Salt Lake in northern Utah. We acquired high-resolution airborne multi spectral imagery of the refuge in 1992 and 2010 to quantify changes in vegetation cover over time. We produced classified vegetation maps for the years 1992 and 2010 to calculate vegetation and water cover in management units. Classification results indicate that invasive vegetation is fast replacing native species in areas adjacent to the water deliver canals. We also compared vegetation changes to historical data provided by refuge managers, and these data contained information about the management activities undertaken in the wetland units over the study period. We found that the managers’ efforts to control the expansion of invasive species—such as keeping the units full of water throughout the year, adjusting water depth to manage salinity levels and aquatic vegetation, and undertaking burning or mechanical disturbance when needed—were successful in most of the units, although some units were still invaded by undesirable plants. Here we demonstrate how wetland managers can use remote sensing and historical data of vegetation cover to understand which native plant species are most susceptible to replacement by invasive species, how vegetation responds to management actions, and ultimately how managers can promote diverse plant communities with high wildlife value.
This is the last in a series of papers clarifying the taxonomy of a critically imperiled assemblage of cochliopid gastropods (Tryonia sensu lato) that inhibit thermal springs in the Chihuahuan Desert (Mexico and United States). We describe 2 new narrowly endemic species of Tryonia from Chihuahua, both of which appear to have been recently extirpated, and we provide new records for 4 congeners (also from Chihuahua) and for a species of Pseudotryonia (from Durango). The 2 new species of Tryonia differ from closely similar regional congeners in shell and penial characters. On the basis of new anatomical data, we also transfer T. bruneiTaylor, 1987 to the genus Juturnia and provide evidence that this species, which was endemic to the Phantom Lake spring complex in west Texas, became extinct sometime after 1984. Our findings provide additional insight into the complex biogeographic history of the Chihuahuan Desert cochliopids and further document the recent decline of regional spring-dwelling biota as a result of groundwater mining.
Organisms often respond to variation in temperature by altering their behavior, but the sensitivity of each behavioral trait depends on the degree to which temperature affects its costs and benefits. Here, we tested whether a little-studied trait, the timing of the first nest departure in the morning, varied in response to ambient temperature at sunrise, sunrise time, and nesting stage (incubation vs. nestling) in female Orange-crowned Warblers breeding on Santa Catalina Island, California. We found that the time of first nest departure was significantly correlated with sunrise time but was not affected by ambient temperature at sunrise. Compared with the nestling period, first nest departure times tended to be later and more variable during incubation, but the causes of these patterns remain to be explored in future studies of avian early-morning behavior.
We captured and marked Mediterranean geckos, Hemidactylus turcicus, occupying a one-story building in southwestern Louisiana in 1999–2000 and 2002–2005 and calculated 2 estimates of growth rate: length growth rate (difference in snout—vent length [SVL] between captures divided by time between captures) and mass growth rate (difference in gecko mass between captures divided by time between captures). Both length growth rate and mass growth rate were significantly negatively correlated with gecko snout—vent length. When data from all years were combined, adult female geckos showed greater mean length growth rates and mean mass growth rates than males, but the trend was not statistically significant. Length growth rate and mass growth rate varied dramatically between years; neither correlated with yearly differences in rainfall. Comparison of our results to studies done in Texas and Florida showed that Mediterranean geckos in Louisiana had the lowest mean length growth rates and a much wider range of variation.
Due to limited water supplies, use of drought-tolerant species to conserve water in irrigated urban landscapes is increasingly important in the Intermountain West. The Colorado Plateau endemic shrub Shepherdia rotundifolia Parry is a potential candidate for use in sustainable urban low-water landscapes (LWLs) for its aesthetic and drought-tolerant qualities. However, the species is difficult to establish in urban landscapes of different fertility and water availability than found in regional native habitats. A better understanding of environmental and genetic constraints, as well as morphological adaptation in native habitats, may facilitate greater use of S. rotundifolia in LWLs. The goal of this study was to investigate variability in environmental conditions, morphology, and genetics among 6 populations of S. rotundifolia along an elevation gradient (range 1200–2500 m) in the species' native range. Aboveground environmental conditions were characterized from 30-year proximal weather station data, intra-annual weather collected on-site, and site relative light intensity (RLI) from hemispherical canopy images. Belowground, we analyzed site-specific soils for texture, pH, salinity, organic matter (OM), and macronutrients. We characterized plant morphology and genetics from leaf area and specific leaf area (SLA), scanning electron microscopic imaging of tri chôme structure and leaf thickness, and amplified fragment length polymorphism (AFLP) genetic variation among populations. Precipitation, air temperature, RLI, and soil properties varied widely among populations. Differences among leaf area, SLA, and leaf trichome structure suggest population-level adaptations consistent with environmental differences, particularly between high- and low-elevation populations. Similarly, distinct AFLP banding patterns among high- and low-elevation populations suggest differences due to isolation by distance. SLA was correlated with RLI, OM, and potassium (K). Relatively high native levels and positive correlation with SLA suggest that K may be a limiting factor in urban landscape soils. Selection of plants adapted to environmental conditions similar to those present in urban landscapes may enhance successful use of S. rotundifolia. Genetic variation also suggests potential for cultivar selection.
The oriental weatherfish (Misgurnus anguillicaudatus) is invasive to 13 U.S. states and at least 9 other countries. Although this cryptic fish species is widespread, very little is known regarding its ecology. We used baited minnow traps to collect 237 individuals from water bodies connected to the Boise River, Idaho. To determine the diet of the fish within this invasive population, we dissected and examined stomach contents of the sampled fish. Most of the stomachs (158 of 237) were empty, and 42 contained only the trap bait. However, 37 contained natural food items. Gravimetric analysis, frequency of occurrence, and mean percent by number all indicated macroinvertebrates as the primary diet component, with chironomid larvae as the most numerous prey eaten. Graphical analysis of prey-specific abundance also indicated that oriental weatherfish fed on a generalized diet, of which detritus is likely an important part. An omnivorous diet may, in part, explain the species' ability to expand its invasive range quickly and successfully. Our findings add to a growing list of traits indicating that the oriental weatherfish fits the profile of a highly successful invader. As such, the oriental weatherfish should be a target species for further ecological research.
We examined the presence of the exotic weevil Rhinocyllus conicus Fröelich on native thistles at high elevations in the Rocky Mountains of Colorado. We tested whether the distribution of R. conicus was related to elevation by performing 2 separate studies. First, transects along an elevation gradient were sampled in Rocky Mountain National Park and presence/absence of R. conicus was scored to infer relationships between environmental variables and weevil occurrence. Second, an experiment was conducted on Niwot Ridge to determine whether weevils were able to complete their reproductive cycle and overwinter at an elevation where they do not currently exist. Results of a logistic regression indicated that R. conicus presence was negatively correlated with elevation. In addition, weevils successfully reproduced at tree line, but climatic limitations suppressed their ongoing presence at this site. The ability of the weevils to utilize native thistles at tree line was unknown prior to this experiment, and our results suggest that within the context of climate warming, the range of R. conicus could expand to include more native alpine thistles in North America.
Understanding factors that influence recruitment can improve wildlife conservation. Endangered black-footed ferrets (Mustela nigripes) rely on prairie dogs (Cynomys spp.) for food and on prairie dog burrows for shelter. We hypothesized that younger female ferrets with greater densities of prairie dogs in their core use area and fewer adult ferrets in their respective prairie dog colony, would produce more kits due to age-dependent productivity, increased food resources, and decreased competition. We used generalized linear mixed-effects regression and Akaike's information criterion adjusted for sample size (AICc) to rank models relating adult female black-footed ferret litter size (range 1–7 kits, n = 24 litters) to female age, core area density of prairie dogs, and adult ferret densities from 3 sites in the USA, 2005–2008. We included year and site as random effects in all models. We observed great model uncertainty; the null model was most supported and received 44% of model weight (w). The next best-supported model included ferret density only (ΔAICc = 1.55, w = 0.20). Ferret density may not have been great enough to negatively affect prey acquisition and litter sizes. Mean litter size did not vary among female ages, but inference was limited because only one individual was >3 years old ( = 2.13 years, SD = 0.99). All adult females produced kits, suggesting that the observed minimum prairie dog density in ferret core use areas (12.3 individuals · ha-1) was above a threshold of minimal prey abundance for reproduction. Our findings support previous selections of reintroduction sites as those meeting minimum resource needs of individual ferrets for reproduction. Future selections of reintroduction sites may become more difficult if the number of areas with the minimum necessary prairie dog density decreases due to disease and reductions in habitat availability.
We studied the diet of the exotic American bullfrog (Lithobates catesbeianus) in Arroyo San Carlos, located in northwestern Baja California, Mexico, during spring and summer 2009. Analysis of 64 stomach contents revealed 15 prey types, of which the exotic red crayfish (Procambarus clarkii) and terrestrial isopods (Armadillidiidae) were the most significant items (according to an index of their relative importance), making up 64% and 31% of the bullfrog's diet, respectively. Diet differed between the sexes, with red crayfish eaten more frequently by males (84%) than females (69%). Bullfrog diet changed with body size, with smaller individuals (≤86 mm) containing woodlice (61%) as the dominant prey type and larger individuals (≥129 mm) containing red crayfish (97%) as the dominant prey type. The average prey size consumed was significantly correlated with body length.
The Red-winged Blackbird (Agelaius phoeniceus) is a polygynous species, and females are typically responsible for the majority of parental care. Despite their limited involvement, males can contribute to reproduction through nest defense and the feeding of nestlings. Some aspects of nest defense may be learned, and older males are more likely to feed young, suggesting that males with previous breeding experience may enjoy higher nest success than their naïve counterparts. We manipulated territory ownership on 10 wetlands in central North Dakota in order to examine the influence of breeding experience on reproductive success. We found no evidence that breeding experience increased nest survival ( = 23.0%) or increased the number of fledglings per nest ( = 2.2). In this population, territory quality may contribute more to nesting success than male parental contributions.
The Mountain Plover (Charadrius montanus) is a declining migratory shorebird that nests on shortgrass prairies across the western Great Plains. This ground-nesting species exhibits an uncommon split-clutch mating system, in which each member of a pair simultaneously incubates a nest and uniparental care continues throughout brood-rearing. We report on an observation of within-season nest reuse in this species. To our knowledge, this report includes the first documented occurrence of 2 different Mountain Plovers using the same nest cup in the same breeding season. Nest reuse could represent a time- and energy-saving strategy for renesting individuals.
Cougars (Puma concolor) are widely distributed throughout the western portion of North America and are generally described as solitary carnivores. Most cougar social interactions have been described as instances of parental care, intraspecific strife, or breeding. We report an apparent case of an adoption of orphaned juveniles in a wild cougar population. We used radiotelemetry and direct visual observations to document an adult female, her 3 dependent offspring, and 2 orphaned juvenile males physically interacting, sharing bed sites, and sharing kills in the late winter of 2007/2008. We consider the potential benefits and/or negative effects of these social interactions, and the role that relatedness and/or familiarity may play in the motivation for developing such associations.
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