Diel and seasonal utilization of home ranges in a small lake by smallmouth bass (Micropterus dolomieui)

Abstract– Diel and seasonal movements of 9 smallmouth bass were monitored by ultrasonic tracking for 1–1.5 years in a small gravel pit lake in northeastern Illinois. Each fish had several home ranges over the study period. Males established home ranges around a nesting site in May and June. During the summer months, smallmouth bass had diurnal, nocturnal, diurnal and nocturnal home ranges. The fish exhibited 2 types of behavior when they were within their home ranges. They were either motionless, which generally occurred on the nocturnal home ranges, or they swam slowly about their home ranges. Rapid directional swimming movements occurred when fish were swimming across the lake or moving between home ranges. The home ranges were transitory. The average size of the reproductive (male) home range was 0.07 hectare; 0.12 hectare for nocturnal home ranges; 0.18 hectare for diurnal home range; and 0.20 for diurnal-nocturnal home range. Generally, reproductive and nocturnal home ranges were smaller; other types could be as small as these but were often larger. However, there was no significant difference in home range sizes.     

Architecture of a fungal fatty acid synthase at 5 A resolution

All steps of fatty acid synthesis in fungi are catalyzed by the fatty acid synthase, which forms a 2.6-megadalton alpha6beta6 complex. We have determined the molecular architecture of this multienzyme by fitting the structures of homologous enzymes that catalyze the individual steps of the reaction pathway into a 5 angstrom x-ray crystallographic electron density map. The huge assembly contains two separated reaction chambers, each equipped with three sets of active sites separated by distances up to approximately 130 angstroms, across which acyl carrier protein shuttles substrates during the reaction cycle. Regions of the electron density arising from well-defined structural features outside the catalytic domains separate the two reaction chambers and serve as a matrix in which domains carrying the various active sites are embedded. The structure rationalizes the compartmentalization of fatty acid synthesis, and the spatial arrangement of the active sites has specific implications for our understanding of the reaction cycle mechanism and of the architecture of multienzymes in general.     

Influenza virus infections in mammals

The natural reservoir of all known subtypes of influenza A viruses are aquatic birds, mainly of the orders Anseriformes and Charadriiformes in which the infection is asymptomatic and the viruses stay at an evolutionary equilibrium. However, mammals may occasionally contract influenza A virus infections from this pool. This article summarizes: (i) natural infections in mammals including pigs, horses, marine mammals, ferrets, minks; (ii) results from experimental infections in several animal models including mice, ferrets, primates, rats, minks, hamsters and (iii) evidence for the increased pathogenicity of the current influenza A H5N1/Asia viruses for mammals. Several reports have shown that a number of mammalian species, including pigs, cats, ferrets, minks, whales, seals and finally also man are susceptible to natural infection with influenza A viruses of purely avian genetic make up. Among the mammalian species naturally susceptible to avian influenza virus the pig and the cat might exert the greatest potential public health impact. Despite numerous studies in animal and cell culture models, the basis of the extended host spectrum and the unusual pathogenicity of the influenza A H5N1 viruses for mammals is only beginning to be unraveled. Recently, also the transmission of equine influenza A virus to greyhound racing dogs has been documented.     

Innovations in the diagnosis of infectious agents of veterinary importance--a seven-league boots fairy tale?

The development of infectiological diagnostic methodology is characterized by saltatoric, revolutionary leaps. Improved sensitivity and specificity, reduction of analytical sample volumes, increased sample throughput, reduced test complexity associated with improved user friendliness are hallmarks of such developments. Apart from purely technical amenities some innovations also enable conceptual adaptations of monitoring strategies. These include the use of diagnostic assays on-site, e. g. in the stable or in the practice. Selecting the assay which is most "fit-for-purpose" among the plethora of sometimes loudly advertised new technology may be difficult even for the well trained and experienced diagnostician. Standardized licensing procedures for infectiological diagnostic kits may be required to guarantee minimal norms of diagnostic quality. At the same time availability of a diversity of diagnostic kits is needed to broaden the base of diagnostic reliability. New infectiological diagnostic innovations will only be useful if the (expanded) results are transposable to the improved practical care of companion animals and farm animal holdings. In addition, the judgment of results, e. g. for epidemiological plausibility, remains a very important issue even when the test results have been produced by novel high technology diagnostics.     

Traditional Mobile Pastoralism in a Contemporary Semiarid Rangeland in Namaqualand,South Africa

Pastoral systems are regarded as complex social-ecological systems with components that interact and change over a range of spatial and temporal scales. As such, herd mobility has traditionally been used to respond to the dynamic nature of these systems. However, mobile pastoral systems around the world are becoming more constrained and increasingly fragmented with important implications for herd mobility. This study assessed the spatial distribution of 256 herds and their mobility patterns over a decade in the 10 villages that comprise the spatially constrained Leliefontein pastoral area in South Africa. We developed a hierarchical model of rangeland use, which showed that several stratified and connected socioeconomic, climatic, and environmental factors determined the spatial and temporal use of grazing areas in this 192 000-ha semiarid environment. At the highest level of use, access to the Leliefontein pastoral area is formally regulated. At the next level, the place of residence of herd owners largely defined which village commons was used by their livestock. At the third level of rangeland use, the wealth status of owners determined where in relation to human settlements their herds were located. At the lowest level in the hierarchy, the locations of water and croplands delineated seasonal grazing areas and the movement of stockposts. These stratified factors, together with the overall variability in grazing resource availability and the different decision making processes involved, resulted in high flexibility and diversity of herd mobility patterns at the lowest level of rangeland use. This, in turn, ensured heterogeneity in resource use over a range of spatial and temporal scales. It was concluded that policies should embrace the complexity of the pastoral system and enable the adaptive management of herds. This could reduce the level of vulnerability experienced by pastoralists to climate variability and wider societal change.     

Multi-scale Mexican spotted owl (<Emphasis Type="Italic">Strix occidentalis lucida</Emphasis>) nest/roost habitat selection in Arizona and a comparison with single-scale modeling results

Context

Organisms commonly respond to their environment across a range of scales, however many habitat selection studies still conduct selection analyses using a single-scale framework. The adoption of multi-scale modeling frameworks in habitat selection studies can improve the effectiveness of these studies and provide greater insights into scale-dependent relationships between species and specific habitat components.

Objectives

Our study assessed multi-scale nest/roost habitat selection of the federally “Threatened” Mexican spotted owl (Strix occidentalis lucida) in northern Arizona, USA in an effort to provide improved conservation and management strategies for this subspecies.

Methods

We conducted multi-scale habitat modeling to assess habitat selection by Mexican spotted owls using survey data collected by the USFS. Each selected covariate was included in multi-scale models at their “characteristic scale” and we used an all-subsets approach and model selection framework to assess habitat selection.

Results

The “characteristic scale” identified for each covariate varied considerably among covariates and results from multi-scale models indicated that percent canopy cover and slope were the most important covariates with respect to habitat selection by Mexican spotted owls. Multi-scale models consistently outperformed their analogous single-scale counterparts with respect to the proportion of deviance explained and model predictive performance.

Conclusions

Efficacy of future habitat selection studies will benefit by taking a multi-scale approach. In addition to potentially providing increased explanatory power and predictive capacity, multi-scale habitat models enhance our understanding of the scales at which species respond to their environment, which is critical knowledge required to implement effective conservation and management strategies.