Reproduction of the prairie skink, Eumeces septentrionalis , in Nebraska

Clutch sizes of the prairie skink, Eumeces septentrionalis , in Nebraska are positively correlated with female snout-vent lengths (SVLs). Data presented in this study and others indicate Nebraska populations of E. septentrionalis have larger average clutch sizes than other populations within this species' range.     

Maternal care of neonates in the prairie skink, Eumeces septentrionalis

Maternal care of neonates has been documented in relatively few species of lizards representing four families. This study documents the occurrence of maternal care of neonates in the prairie skink, Eumeces septentrionalis . Observations made herein indicate that individual variation in maternal behavior existis in this species.     

Bibliography and subject index of the prairie skink, Eumeces septentrionalis (Baird) (Sauria: Scincindae)

The prairie skink, Eumeces septentrionalis , is a small, semifossorial lizard inhabiting the tall-grass prairies and savannas of the central lowland province region of North America. This study provides an extensive bibliography and subject index as a tool for current and future workers studying E. septentrionalis and related species.     

Influence of substrate size, Cladophora , and caddisfly pupal cases on colonization of macroinvertebrates in Sagehen Creek, California

Colonization of stream macroinvertebrates onto artificial substrates was examined in Sagehen Creek, California, during 1993. Substrate size and presence or absence of pupal cases of the caddisfly Anagapetus (Glossosomatidae) were examined as possible influences on macroinvertebrate colonization. Macroinvertebrates were collected from substrates after 60 d of incubation and identified to the lowest feasible taxonomic unit. Dry weight of the filamentous green alga Cladophora also was determined for each substrate. A general linear model indicated a significant positive relationship between both substrate size and presence of pupal cases on richness ( P Anagapetus cases on Micrasema bactro , Epeorus , and Rhyacophila sp. 1, and of substrate size on Hydropsyche occidentalis and Epeorus . Neither cases nor substrate size had a significant effect on Cladophora density ( P > 0.05). There were significant negative correlations between Cladophora density and both Shannon H′ and J′ indices. There were significant positive relationships between Cladophora density with Baetis , Simulium , and Chironomidae density. Combined main effects of substrate size, Anagapetus pupal cases, and Cladophora have dynamic influences on this macroinvertebrate fauna. This study demonstrates the complex interplay of biotic and abiotic factors that determine macroinvertebrate distribution and abundance in this system.     

Influence of water size and type on bat captures in the lower Sonoran Desert

We compared bat use by mist-netting at 4 different types of wildlife water developments in southwestern Arizona during summer 2000 and 2001. Scaling our results by netting effort, we caught bats more frequently and observed higher species diversity at tinajas (modified natural rock pools) with larger open-water area compared with ""guzzler"" type water developments that had less open water and more obstacles to bat flight. We caught the fewest bats at guzzlers with buried concrete vault drinkers, which impede bat access and have the smallest areas of open water. Water development designs that minimize evaporative water loss by reducing the amount of open water apparently reduce use by bats in this area.     

Influence of soil and site characteristics on Palouse prairie plant communties

The structure of grassland communities can vary widely in response to heterogeneous habitat variables. In this study we document plant communities, soil types, and site characteristics for 12 Palouse prairie remnants in southeastern Washington and northern Idaho. We used general linear models to test the predictive value of 6 biophysical variables (slope, aspect, distance from edge, edge type, vegetation structure, and soil type) on 3 plant community metrics: species richness, Simpson’s diversity index, and the dominance of exotic species. From full models including all variables, we used Akaike’s information criterion (AIC) to select the best model for each metric. Aspect and vegetation structure were significant predictors of species richness ( R 2 = 0.08) and diversity ( R 2 = 0.09), while aspect, soil type, distance from edge, and edge type (type of adjacent matrix habitat) influenced the dominance of exotic species ( R 2 = 0.28). Additional soil sampling determined that the depth to a restrictive layer also had significant impacts on the dominance of exotic species ( R 2 = 0.31). This study confirms that biophysical characteristics influence Palouse prairie plant communities and may help set research and conservation priorities for isolated and uninventoried remnants.     

Influence of black-tailed prairie dog towns ( Cynomys ludovicianus ) on carnivore distributions in the Oklahoma Pandhandle

Carnivores were recorded at prairie dog towns and non-prairie dog town paired sites in the Oklahoma Panhandle over 4 sampling sessions from October 1995 to February 1997. We established carnivore presence through the use of baited tracking plates dusted with chalk and matched with infrared-triggered cameras. Five carnivore species were recorded at both prairie dog towns and paired sites across the Oklahoma Panhandle. Of these, 4 were recorded with sufficient regularity to permit analyses. Carnivores were analyzed at prairie dog towns across the entire Panhandle and in the Panhandle's westernmost county (Cimarron County) only. Canids showed no significant preference for prairie dog towns or other areas. In the Oklahoma Panhandle and Cimarron County only, occurrence of swift fox ( Vulpes velox ) between prairie dog towns and control sites was insignificant. Badgers ( Taxidea taxus ) and spotted skunks ( Spilogale putorius ) occurred significantly more often at prairie dog towns in Cimarron County but not in the Panhandle. No single mustelid species showed a significant association with either prairie dog towns or non-prairie dog town habitats. Our results indicate that whereas prairie dog towns do attract some carnivore species, the presumption that prairie dogs are ""keystone species"" for so many organisms (especially threatened or endangered species) in the current plains ecosystem may not be as clear as previously thought.     

Capture rates of reptiles and amphibians on black-tailed prairie dog ( Cynomys ludovicianus ) colonies and on uncolonized prairie in Colorado

Prairie dog eradication negatively affects dependent wildlife. Assessing the effects of prairie dog activities on reptiles and amphibians may depend upon the efficacy of trapping designs. We compared capture rates of reptiles and amphibians on black-tailed prairie dog ( Cynomys ludovicianus ) colonies and on adjacent uncolonized short-grass prairie, using funnel traps and pitfall traps with drift fences, as well as ground captures. We captured 152 reptiles and amphibians representing 10 species. We captured 51.3% of all reptiles and amphibians on colonies, compared to 48.7% from uncolonized sites. Overall, captures of reptiles and amphibians were similar on colonies and uncolonized sites for all capture methods combined. We achieved higher capture rates on uncolonized sites using funnel traps and pitfall traps but higher capture rates on colonies for ground captures. For all years on all sites combined, we captured significantly more animals in funnel traps (52.6%), surpassing pitfall trap captures (23.0%) and ground captures (24.3%). We recommend using multiple Y-shaped drift fence arrays ≥7.6 m in length, funnel traps with double-ended openings, and black-colored pitfall traps with opening diameters ≥30 cm.     

Observations on body mass of prairie dogs in urban habitat

The black-tailed prairie dog is an important component of prairie and steppe ecosystems. Currently many prairie dog colonies are fragmented by, or adjacent to, urban development, but little is known about what effects urbanization may have on these animals. I compare body weights and sex ratios of prairie dogs in isolated urban habitat in Denver, Colorado, to published data for black-tailed prairie dogs at the same time of year. Prairie dogs in this study had summer weights similar to those reported in the literature, although males apparently gained weight earlier in the year, and observed sex ratios were not significantly different from 1:1. Although prairie dogs in urban areas face numerous threats, my study provides no evidence that urban forage is limited enough to result in decreased body mass or skewed sex ratios of urban prairie dogs.     

Species composition, distribution, and phytosociology of Kalsow Prairie, a mesic tall-grass prairie in Iowa

Normal 0 false false false EN-US X-NONE X-NONE MicrosoftInternetExplorer4 /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Table Normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-priority:99; mso-style-qformat:yes; mso-style-parent:""; mso-padding-alt:0in 5.4pt 0in 5.4pt; mso-para-margin:0in; mso-para-margin-bottom:.0001pt; mso-pagination:widow-orphan; font-size:11.0pt; font-family:"Calibri","sans-serif"; mso-ascii-font-family:Calibri; mso-ascii-theme-font:minor-latin; mso-fareast-font-family:"Times New Roman"; mso-fareast-theme-font:minor-fareast; mso-hansi-font-family:Calibri; mso-hansi-theme-font:minor-latin; mso-bidi-font-family:"Times New Roman"; mso-bidi-theme-font:minor-bidi;} Species composition, distribution, and phytosociology of an 8 hectare area of tall grass prairie was intensively studied. Elevation and soils data were correlated with species distribution patterns. All species showed a response. Nine general patterns of distribution were observed in relation to elevation and soil types. Ordination and interspecific association analyses were used to identify clusters or groups of species having similar ecological amplitudes. Sporobolis heterolepis is the dominant plant of the upland prairie. The vegetation of the prairie is best described and represented by the continuum concepts of phytosociology.       

Effects of prairie dog rodenticides on deer mice in western South Dakota

Mortality of nontarget small mammals was determined after application of three black-tailed prairie dog ( Cynomys ludovicianus ) rodenticide treatments (prebaited zinc phosphide, prebaited strychnine, and strychnine alone) in western South Dakota. Immediate (September 1983) and long-term (September 1983 through August 1984) impacts on deer mouse ( Peromyscus maniculatus ) relative densities were evaluated and the three rodenticide treatments were compared for efficacy. The three treatments had no significant (α < .10) immediate impacts on deer mouse relative densities, although zinc phosphide did lower them; that impact was not, however, long term. Long-term impacts of the two strychnine treatments were variable, with an increase in deer mouse densities with the strychnine only treatment. Overall, comparisons among the three treatments indicated that zinc phosphide was more effective than either strychnine treatment in reducing deer mouse densities.     

Spatiotemporal variation in phenology and abundance of floral resources on shortgrass prairie

Phenology and abundance of the floral resources used by bees and other flower-visiting insects were recorded weekly from permanent quadrats for two years on two shortgrass prairie sites in the Laramie Basin, Wyoming. Each site was composed of three distinct plant communities. Results suggest considerable spatiotemporal variability in floral resources. Specifically, most species at both sites showed the following temporal variation: (1) bloom times between one and two weeks earlier in the second year; (2) differences of approximately 1&ndash;2 weeks in bloom span between years; (3) substantial differences in abundance of flowers between years. Species blooming during the last half of the census period were significantly more variable in flower abundance between years than those blooming earlier. Spatial variation was shown both by differences between sites and between plant communities within sites in the direction and magnitude of between-year changes in floral abundance. For example, floral production at Boulder Ridge in 1976 was much lower than in 1975, but at The Dirt Farm between-year differences were less pronounced and depended upon season. Similarity measures and cluster analysis suggest differences in the structure of the bloom season at both sites between years, and a relatively rapid turnover of floral composition within years such that bees face a very different flora over the latter part of their flight seasons relative to that encountered initially. Evidence from other reports support the hypothesis of spatiotemporal unpredictability of floral resources.     

Successful nesting by a Bald Eagle pair in prairie grasslands of the Texas Panhandle

We observed a breeding Bald Eagle ( Haliaeetus leucocephalus ) pair nesting in a short-grass prairie and agricultural community on the southern Great Plains of the Texas Panhandle in 2004 and 2005. The nesting eagles produced 1 fledgling in 2004 and 2 fledglings in 2005. Our assessment of landcover types within a 5-km radius of the nest indicated that grasslands accounted for most of the area (90%), followed by agricultural lands (8%). Black-tailed prairie dog ( Cynomys ludovicianus ) colonies occupied 2.5% of the area, and single human residences with associated structures (i.e., barns) occupied 2.5 ha in surface area was 51 km from the nest. An analysis of regurgitated castings collected near the nest revealed a mammalian-dominated, breeding-season diet with black-tailed prairie dogs occurring in 80.9% of the castings. Other identified prey included cottontails ( Sylvilagus spp., 15.9%), black-tailed jackrabbits ( Lepus californicus , 3.2%), pronghorn ( Antilocapra americana , 3.2%), and plains pocket gopher ( Geomys bursarius , 1.6%). Bird remains were also present in 34.9% of the castings. This is the first reported successful nesting of Bald Eagles in the panhandle region of Texas since 1916; the nest is particularly unique because of its distance from any substantial body of water.     

Distribution and first reports of Branchiobdellida (Annelida: Clitellata) on crayfish in the prairie provinces of Canada

Orconectes virilis (northern crayfish) were collected from 67 sites in Alberta, Saskatchewan, Manitoba, and far-western Ontario, Canada, and yielded 2 species of branchiobdellidans, Cambarincola vitreus and Cambarincola chirocephalus. This is the first report of branchiobdellidans in the Prairie Provinces. Cambarincola vitreus was distributed across the study area, but C. chirocephalus appeared to be restricted to southeastern Saskatchewan, southern Manitoba, and the site in western Ontario. Neither branchiobdellidan species was observed on crayfish in the Beaver River or the South Saskatchewan River and associated tributaries upstream (west) of Saskatoon, Saskatchewan, despite multiple sampling at these locations.     

Association of black-tailed prairie dog colonies with cattle point attractants in the Northern Great Plains

In October 1991 we recorded all black-tailed prairie dog ( Cynomys ludovicianus ) colonies and cattle points in a 1248-km 2 study area in southwest North Dakota and southeast Montana. Cattle point attractants were defined as fabricated water tanks and long-term supplemental feed sites. We found that a signivicant number of prairie dog colonies encompassed or adjoined cattle point attractants ( p < .001). Prairie dog colonies associated with cattle point attractants were a mean distance of 1.0 km from the next nearest town. The existence of cattle point attractants may encourage prairie dog colonization. Conversely, refraining from using long-term cattle point attractants can discourage prairie dog colonization.     

Effects of habitat on clutch size of ornate tree lizards, Urosaurus ornatus

Normal 0 false false false EN-US X-NONE X-NONE /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Table Normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-priority:99; mso-style-qformat:yes; mso-style-parent:""; mso-padding-alt:0in 5.4pt 0in 5.4pt; mso-para-margin:0in; mso-para-margin-bottom:.0001pt; text-indent:.25in; mso-pagination:widow-orphan; font-size:11.0pt; font-family:"Calibri","sans-serif"; mso-ascii-font-family:Calibri; mso-ascii-theme-font:minor-latin; mso-fareast-font-family:"Times New Roman"; mso-fareast-theme-font:minor-fareast; mso-hansi-font-family:Calibri; mso-hansi-theme-font:minor-latin; mso-bidi-font-family:"Times New Roman"; mso-bidi-theme-font:minor-bidi;} Clutch size is an important determinant of female reproductive success in reptiles. Although female body size explains much variation in clutch size, other important factors include differences in food availability, predation risk, morphology, and demography. Ornate tree lizards, Urosaurus ornatus, display extensive variation in life history traits, including clutch size. Tree lizards primarily use 2 distinct habitat types&mdash;trees and rock surfaces&mdash;which influence both the performance and morphology of this species and may affect life history traits such as clutch size. As food availability, microclimate, and, potentially, predator escape probabilities differ between these 2 habitats, I predicted that tree- and rockdwelling lizards would allocate resources toward clutch size differently. Clutch size variation was compared among 15 populations of U. ornatus sampled from the different habitat types. Urosaurus ornatus individuals living on trees had significantly larger clutches than those living on rocks, even after including the effects of body size and environment. Two potential mechanisms leading to larger clutches in tree-dwelling lizards are (1) differences in food availability and (2) differences in performance (sprint vs. endurance) requirements for predator escape in the 2 habitats. Inconsistent distribution of habitat type across the phylogenetic tree indicates either many cases of independent evolution in the allocation strategies of these lizards or a consistent phenotypically plastic response to similar environmental challenges in different populations. El tama&ntilde;o de puesta es un determinante importante del &eacute;xito reproductivo de las hembras. Aunque el tama&ntilde;o corporal de la hembra explica gran parte de la variaci&oacute;n en el tama&ntilde;o de puesta de los reptiles, otros factores importantes incluyen las diferencias en la disponibilidad de alimento, el riesgo de depredaci&oacute;n, la morfolog&iacute;a y la demograf&iacute;a. La lagartija arbolera Urosaurus ornatus exhibe gran variaci&oacute;n en caracter&iacute;sticas de historia de vida, incluyendo el tama&ntilde;o de puesta. Esta lagartija usa principalmente dos h&aacute;bitats distintos, &aacute;rboles y superficies de rocas, los cuales influyen tanto en el desempe&ntilde;o como en la morfolog&iacute;a de esta especie y pueden afectar las caracter&iacute;sticas de historia de vida como el tama&ntilde;o de puesta. En vista de que la disponibilidad de alimento, el microclima y posiblemente el escape de los depredadores difieren entre estos dos h&aacute;bitats, fue posible predecir que las lagartijas que viven en &aacute;rboles distribuir&iacute;an sus recursos de una manera diferente a la de las lagartijas que viven en las rocas con respecto al tama&ntilde;o de puesta. Comparamos la variaci&oacute;n en el tama&ntilde;o de puesta entre 15 poblaciones de U. ornatus provenientes de los dos tipos de h&aacute;bitat. Las Urosaurus ornatus que viven en los &aacute;rboles tuvieron puestas considerablemente m&aacute;s grandes que las que viven en las rocas, aun despu&eacute;s de incluir los efectos del tama&ntilde;o corporal y del ambiente. Dos mecanismos que podr&iacute;an llevar a puestas m&aacute;s grandes en lagartijas que viven en &aacute;rboles son (1) diferencias en la disponibilidad de alimento, y (2) diferencias en las capacidades necesarias (velocidad/resistencia) para eludir depredadores en los dos h&aacute;bitats. La distribuci&oacute;n del tipo de h&aacute;bitat en el &aacute;rbol filogen&eacute;tico indica, o muchos casos de evoluci&oacute;n independiente en las estrategias de asignaci&oacute;n de recursos de estas lagartijas, o una reacci&oacute;n sistem&aacute;tica y fenot&iacute;picamente pl&aacute;stica a presiones ambientales similares en distintas poblaciones.     

Influence of soil water availability on competition among leafy spurge ( Euphorbia Esula ) and grasses

Some perturbations differentially influence invasive plant and grass production. For example, growth regulator herbicides and biological control agents can dramatically reduce leafy spurge production while having little or no influence on grass production, and overgrazing can reduce grass production while not substantially influencing leafy spurge production because cattle typically ingest little or no leafy spurge. To predict how grass production will respond to a perturbation that influences only leafy spurge and to predict how leafy spurge production will respond to a perturbation that affects only grasses, competitive relationships must be understood. Seeding mixtures of leafy spurge and 2 grasses were planted in experiments and grown for 127 days to determine whether different water application regimes influenced competition among these 3 species. Competition became less intense as the number of water applications increased. If this finding holds true under field conditions, then it indicates that competition is less intense in years and locations with numerous precipitation events. Competitive interactions (i.e., competition coefficients) were less variable when water was applied more frequently, but the ability of models to account for variation in plant weight (i.e., r 2 ) was not influenced by the frequency of water application. This suggests that models will predict invasive plant and grass biomass with equal accuracy in years with few or many precipitation events. Competitive effects were similar regardless of grass species, which suggests that grasses might be considered collectively in predicting response to perturbations in the field.     

Influence of ponderosa pine overstory on forage quality in the Black Hills, South Dakota

Forage quality was assessed in pole and sapling ponderosa pine ( Pinus ponderosa ) stands growing at five stocking levels—0, 5, 14, 23, and unthinned (which approximated 40 m 2 /ha basal area)—in the Black Hills of South Dakota. Crude protein, acid detergent fiber, acid detergent lignin, ash, calcium, and phosphorus were evaluated for cream peavine ( Lathyrus ochroleucus ), bearberry ( Arctostaphylos uva-ursi ), and timber oatgrass ( Danthonia intermedia ). Acid detergent fiber, acid detergent lignin, and ash showed some significant differences among growing stock levels for cream peavine growing in sapling stands. Crude protein content of timber oatgrass was different among growing stock levels in pole stands. In all cases, however, no trends or patterns relative to stocking levels were evident. When understory forage quality was compared within pole and sapling stands, only 4 of 18 possible comparisons were significant. In general, modifying the overstory of ponderosa pine in the Black Hills by clearcutting or thinning did not result in predictable changes in nutritional values of selected understory species.     

Qualitative relations of egg size,egg production and colony size in some ponerine ants (Hymenoptera: Formicidae)

The sizes of eggs and reproductives of 13 species of ponerine ant were measured, and information about the mature colony sizes, ovarial anatomy and individual fecundities of a selection of ponerine species was assembled. Inter-specific variation in the size of colonies was found to be poorly related to aspects of individual fecundity, and although the few cases of polygyny were associated with larger colony sizes, monogynous species often attained even larger sizes. Within the subfamily individual fecundity may be increased primarily by a decrease in the maternal investment in individual eggs, and perhaps to a lesser extent by an increase in the number of ovarioles in each ovary or an increase in the length of each ovariole. The diet of a species and the longevity of adult worker ants relative to the duration of their larval development are suggested as factors besides reproductive characteristics that might also contribute to differences in colony size.