Estimating the abundance or density of populations is fundamental to the conservation and management of species, and as landscapes become more fragmented, maintaining landscape connectivity has ...become one of the most important challenges for biodiversity conservation. Yet these two issues have never been formally integrated together in a model that simultaneously models abundance while accounting for connectivity of a landscape. We demonstrate an application of using captureârecapture to develop a model of animal density using a leastâcost path model for individual encounter probability that accounts for nonâEuclidean connectivity in a highly structured network. We utilized scat detection dogs (Canis lupus familiaris) as a means of collecting nonâinvasive genetic samples of American mink (Neovison vison) individuals and used spatial captureârecapture models (SCR) to gain inferences about mink population density and connectivity. Density of mink was not constant across the landscape, but rather increased with increasing distance from city, town, or village centers, and mink activity was associated with water. The SCR model allowed us to estimate the density and spatial distribution of individuals across a 388 km² area. The model was used to investigate patterns of space usage and to evaluate covariate effects on encounter probabilities, including differences between sexes. This study provides an application of captureârecapture models based on ecological distance, allowing us to directly estimate landscape connectivity. This approach should be widely applicable to provide simultaneous direct estimates of density, space usage, and landscape connectivity for many species.
No defects related to deficiency of the Wiskott-Aldrich Syndrome protein (WASp) have been described in osteoclasts. Here we show that there are significant morphologic and functional abnormalities. ...WASp-null cells spread over a much larger surface area and are highly polykaryotic. In their migratory phase, normal cells assemble clusters of podosomes behind their leading edges, whereas during the bone resorptive phase multiple podosomes are densely aggregated in well-defined actin rings forming the sealing zone. In comparison, WASp-null osteoclasts in either phase are markedly depleted of podosomes. On bone surfaces, this results in a failure to form actin rings at sealing zones. Complementation of WASp-null osteoclasts with an enhanced green fluorescent protein (eGFP)-WASp fusion protein restores normal cytoarchitecture. These structural disturbances translate into abnormal patterns of bone resorption both in vitro on bone slices and in vivo. Although physiologic steady-state levels of bone resorption are maintained, a major impairment is observed when WASp-null animals are exposed to a resorptive challenge. Our results provide clear evidence that WASp is a critical component of podosomes in osteoclasts and indicate a nonredundant role for WASp in the dynamic organization of these actin structures during bone resorption. (Blood. 2004;103:3552-3561)
Shorebirds in the East Asian-Australasian Flyway have experienced population declines linked to loss of coastal wetlands. Despite this vulnerability to habitat loss, shorebirds regularly use ...artificial habitats, especially for high-tide roosting. Understanding the distribution of shorebirds in artificial versus natural roosts could inform habitat management strategies aimed at population recovery. We analysed time-series of high-tide shorebird monitoring data from five developed regions of Australia where artificial habitat use has previously been documented and made three key discoveries. First, artificial habitat use was generally high across the regions, with >50% of the average proportion of the regional population of 39 of 75 species-region combinations (52%) using artificial habitats at high tide. Second, in 84% of species-region combinations the average proportion of birds that used artificial habitats from the time of their establishment onward did not show a significant temporal trend. Third, migratory and coastal specialist species showed lower proportional artificial habitat use than non-migratory and generalist/inland specialist species. These findings showing consistent, widespread use of artificial habitats by large shorebird aggregations at high tide suggest that a framework for high-tide habitat management that includes artificial habitats alongside preservation of remaining natural habitats could make a significant contribution to shorebird conservation in Australia.
As part of ongoing work on the Flora of the Southeastern United States (Weakley & Southeastern Flora Team 2023) and related projects, as well as for general floristic, conservation, and scientific ...work in eastern North America, it is essential to document taxonomic and nomenclatural changes and significant distribution records. Here, we propose six new species of graminoids (two Rhynchospora, three Dichanthelium, and one Anatherum)—five from fire-maintained pine savannas and embedded wetlands of the southeastern Coastal Plain and one from the floristically and ecologically related fire-maintained pine savannas of North Andros Island in The Bahamas. We provide rationale and documentation for the “taxonomic resurrection” of Vaccinium ashei, an economically important member of Vaccinium sect. Cyanococcus, based on morphology, estimation of ploidy level with flow cytometry, and phylogenomic analysis based on high-throughput DNA sequencing. We make four new combinations in Convolvulus to accommodate the inclusion of Calystegia in Convolvulus to resolve paraphyly. We also make six new combinations necessary to recognize sect. Leptopogon of Andropogon at generic rank, as Anatherum, based on the phylogenetic work of other researchers and the previously incomplete transfer of recognized species to Anatherum, providing the needed names to recognize this group of species in genus Anatherum in North American floristic treatments. We document the surprising discovery of Carex lutea, previously believed to be endemic to two counties in eastern North Carolina, in two counties in the panhandle of Florida, and a county in eastern South Carolina—discoveries aided by iNaturalist and Facebook. We document new states as being within the distribution ranges of additional species: Quercus similis (Florida), Juncus brachycephalus (Arkansas and Missouri), Rhexia mariana var. mariana (Ohio), Asarum acuminatum and Elionurus tripsacoides (Alabama), and Mecardonia procumbens (Georgia). Other important distributional records, many representing rediscoveries of conservationally significant, extant populations of plants previously considered of only historical occurrence in a state, are also reported: Alabama (Arnica acaulis, Asclepias connivens, Berberis canadensis, Bulbostylis warei, Ctenodon viscidulus, Parnassia grandifolia, and Pinguicula pumila) and Georgia and Florida (Lobelia boykinii).
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, UILJ, UKNU, UL, UM, UPUK
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