398 research outputs found
Wood Frog (Rana sylvatica) Use of Wildlife Ponds in Northcentral Arkansas
Forty-one wildlife ponds were monitored between 1988 and 1992 for breeding use by wood frogs (Rana sylvatica). Data were collected on egg deposition and pond characteristics. Breeding activity and characteristics were similar to that reported in other portions of the range of the wood frog. We also monitored 15 newly-constructed ponds to determine chronological breeding patterns. Data collected for each site indicated a significant increase (P\u3c 0.05) in the number of egg masses deposited in ponds as they age from 1-3 years during our study period. Increased chronological use of newly-constructed ponds may be due to localized population increase resulting from greater availability of breeding habita
Long-Term White-Tailed Deer Harvest Trends for the Southcentral United States
White-tailed deer herd size across the southcentral states continues to increase. Concurrent with this increase has come a total harvest level increase for most states. Southcentral states have increased bag limits on antlerless deer to insure that herd health is maintained as herd sizes approach total carrying capacity. Harvest growth rates, however, show irregularities from year to year. The cyclic pattern of harvest (and population) growth rate is of shorter duration than would be expected in a large ungulate population. An exogenous influence is suspected. Cyclic patterns in harvest growth rates move opposite the growth rate of epizootic hemorrhagic disease incidence in southcentral counties. Initial results suggest causality between disease incidence and harvest growth rate. As herds approach carrying capacity on many southern sites, management challenges increase
Genic Variation in White-tailed Deer from Arkansas
Liver and kidney samples of 33 white-tailed deer (Odocoileus virginianus) representing three populations in Arkansas were examined with horizontal starch gel electrophoresis. Of 17 loci examined, only PGM-1 and ES-2 exhibited polymorphism. Average individual heterozygosity, ranging from 2.3% to 4.7% with a mean of 3.1 %, was much lower than that reported for white-tailed deer in other parts of its range. The three populations examined in this study were highly similar based on Rogers\u27 genetic similarity coefficient
Factors Affecting Annual Deer Harvest in Arkansas
An understanding of general forces affecting annual harvest is essential to the management of white-tailed deer (Odocoileus virginianus). A predictive model based on such factors would be valuable to managers. The relationship between 27 different variables and annual, legal deer harvest in Arkansas was evaluated for 1957-1986. Variables most affecting harvest were soybean acreage, hay acreage, number of days in the deer season, rain during the deer season, and total state timber production, total state pulpwood production, and deer harvest 2 years prior. Because significant autocorrelation and heteroscedasticity were present in the variables, log-linear, first differencing and non-linear quasi-Newton regression methods were used in addition to ordinary least squares. First differencing removed autocorrelation and heteroscedasticity, but fit was not acceptable (R2 = 0.710). Non-linear estimation of first differenced log transformed variables provided an acceptably high R2 (0.896) with high significance of the individual parameter estimators. Factors associated with habitat quality 2 years prior most affected present-year deer harvest
Perceived Damage by Elk in the Arkansas Ozarks
Wildlife managers in Arkansas are faced with managing a growing population of Rocky Mountain elk (Cervus elaphus neloni) that has extended its range to incorporate private lands near the Buffalo National River (BNR) in northcentral Arkansas. This range expansion has created conflicts between private landowners and wildlife management personnel. To document the extent of damage and assess attitudes of landowners with elk on their land, interviews were conducted with landowners who contacted us or the Arkansas Game and Fish Commission about problems with elk. A survey also was created and sent to landowners who live near the BNR in Boone and Newton counties and who may have elk on their land. Ten of 18 respondents with elk on their land reported having a problem with nuisance activity. Landowners indicated that most damage was to pastures, hay crops, and food plots. Damage appeared to occur more often in summer, when elk home ranges were smallest, than in other seasons. Landowners incurring damage from elk had a strong negative opinion. Continued research into effective management practices should be conducted to properly manage this growing population of elk and reduce conflicts between elk and Arkansas landowners
Arms and the mollusc: An evolutionary arms race has produced armor based on molluscan biomineralization
A.G.C. acknowledges funding from Project No. PID2020116660GB-I00, funded by Spanish Ministry of Science and Innovation (MCIN/AEI/10.13039/ 501100011033).
Open Access funding provided thanks to the CRUE-CSIC agreement with Springer Nature.More than half a billion years ago in the early Cambrian period, there began an evolutionary arms race between molluscs and their predators, in which molluscs developed armor in the form of a biomineral exoskeleton—a shell—to avoid being eaten by predators that were developing jaws and other novel means of devouring them. The mollusc fabricates multiple layers of shell, each of a particular microstructure of a composite between an inorganic and an organic phase, which are the end result of more than 500 million years of coevolution with increasingly deadly predators. Molluscan biomineralization is an excellent case to study how a biological process produces a complex structure, because the shell is constructed as an extracellular structure in which all construction materials are passed out of the cells to self-assemble outside the cell wall. We consider what is known of the development of multilayer composite armor in the form of nacre (mother of pearl) and the other strong microstructures with which molluscs construct their shells.MCIN/AEI/10.13039/ 501100011033 PID2020116660GB-I00CRUE-CSI
Samples from Differentiated Asteroids; Regolithic Achondrites
Differentiated and partially differentiated asteroids preserve a glimpse of planet formation frozen in time from the early solar system and thus are attractive targets for future exploration. Samples of such asteroids arrive to Earth in the form of achondrite meteorites. Many achondrites, particularly those thought to be most representative of asteroidal regolith, contain a diverse assortment of materials both indigenous and exogenous to the original igneous parent body intermixed at microscopic scales. Remote sensing spacecraft and landers would have difficulty deciphering individual components at these spatial scales, potentially leading to confusing results. Sample return would thus be much more informative than a robotic probe. In this and a companion abstract [1] we consider two regolithic achondrite types, howardites and (polymict) ureilites, in order to evaluate what materials might occur in samples returned from surfaces of differentiated asteroids and what sampling strategies might be prudent
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