A Multilocus Genotypic Analysis of Cryptosporidium meleagridis

ABSTRACT. Cryptosporidium meleagridis is a common cause of cryptosporidiosis in birds. In addition, recent reports have described the parasite as an etiologic agent of cryptosporidiosis in both immunocompetent and immunocompromised humans. Therefore, it is important to genetically characterize isolates of C. meleagridis from different hosts and geographic areas, and to develop molecular tools to differentiate isolates from various hosts or areas. In this study, a total of 11 isolates of Cryptosporidium meleagridis from both human and avian hosts were examined at three genetic loci: the small-subunit rRNA, 60-kDa glycoprotein precursor, and 70-kDa heat shock protein genes. Two genotypes of C. meleagridis were seen at the small-subunit rRNA locus. These differed from each other by the presence or lack of a heterogeneous copy of the gene and an ATT repeat. The 60-kDa glycoprotein precursor gene divided these eleven isolates of C. meleagridis into six genotypes with high sequence diversity between groups. The highest genetic heterogeneity, however, was seen at the 70-kDa heat shock protein locus, and was primarily present at the 3'end of the gene. This heterogeneity separated eight isolates of C. meleagridis into six genotypes. These data could be useful in the development of molecular tools to promote understanding of the transmission of C. meleagridisi in humans.     

Assessing transportation by the covariance of species with comments on contagious and random distributions

The paleoecologist must be able to distinguish a transported assemblage from an in situ one. A method is proposed to assess whether the post-mortem transport of individuals affected their observed spatial (horizontal) distribution. The spatial distribution of a species can be random or contagious. The spatial distribution of individuals of a species in the death assemblage produced by the cumulation of many temporally discrete inputs will be random if the individual inputs are random and contagious if the inputs are contagious. The spatial distribution patterns of several species should not covary in the absence of physical disturbance regardless of their own distributions, however. The degree of covariance between individuals of several species of similar hydrodynamic propensity is dependent on the amount and intensity of postmortem movement. The more species that covary, and the larger the size classes that covary, the more likely that transportation played an important role in the species' distribution patterns. Conversely, the absence of covariance suggests that, for at least some species, biological factors determined the species' spatial distributions. Similarly, covariance of vertical distribution patterns might suggest homogenization. by bioturbational or physical mixing.     

Detectability and Response Rates of Ferruginous Pygmy-Owls

Abstract: Survey techniques that are both reliable and efficient are necessary to accurately estimate population parameters, especially for rare species. Cactus ferruginous pygmy-owls (Glaucidium brasilianum cactorum; hereafter pygmy-owls) have declined in southwestern North America and are surveyed often to comply with federal law. We studied owl responses to broadcasted calls to quantify how detectability and response rates (owls/station/transect) vary with environmental, spatial, temporal, and weather-related factors. We surveyed owls along 392 transects (1,113 km) throughout Sonora, Mexico, including a subset of 14 transects (47.2 km) that we surveyed repeatedly to assess factors that affected response rates. We challenged 17 adults and 23 juveniles that were radiomarked, adults attending 50 occupied nests, and adults attending 6 groups of radiomarked juveniles to respond to broadcasted calls to assess factors that affected detectability. Across Sonora, response time averaged 2.6 ± 0.1 minutes (xM ± SE, n = 520), with 99 ± 0.4% of owls detected in ≤8 minutes; response distance averaged 251 ± 7 m, with 91 ± 1% of owls detected at ≤400 m. Response time decreased by an average of 4 ± 2% and response distance decreased by 12 ± 3 m with each half-month period from early courtship through brooding (P ≤ 0.035). Response time averaged 39 ± 24% faster during morning than midday at occupied nests. Detectability was 1.0 ± 0.0 when surveyors were 100 m from occupied nests and decreased to 0.78 ± 0.10 when surveyors were 500 m from occupied nests. Detectability was higher during incubation, brooding, and natal dispersal (0.89 ± 0.05-1.0 ± 0.0) than during fledgling-dependency (0.50 ± 0.20-0.67 ± 0.19). Response rates of males did not vary from early courtship to brooding (P = 0.84), yet those of females decreased systematically to zero across the same period (P < 0.001). Because detectability of pygmy-owls remains consistently high during nesting, response rates generated from carefully designed surveys can provide reliable estimates of occupancy and abundance.     

Evaluating Detection Probabilities for American Marten in the Black Hills,South Dakota

ABSTRACT Assessing the effectiveness of monitoring techniques designed to determine presence of forest carnivores, such as American marten (Martes Americana), is crucial for validation of survey results. Although comparisons between techniques have been made, little attention has been paid to the issue of detection probabilities (p). Thus, the underlying assumption has been that detection probabilities equal 1.0. We used Presence-Absence data obtained from a track-plate survey in conjunction with results from a saturation-trapping study to derive detection probabilities when marten occurred at high (>2 marten/10.2 km²) and low (≤1 marten/10.2 km²) densities within 8 10.2-km² quadrats. Estimated probability of detecting marten in high-density quadrats was p = 0.952 (SE = 0.047), whereas the detection probability for low-density quadrats was considerably lower (p = 0.333, SE = 0.136). Our results indicated that failure to account for imperfect detection could lead to an underestimation of marten presence in 15–52% of low-density quadrats in the Black Hills, South Dakota, USA. We recommend that repeated site-survey data be analyzed to assess detection probabilities when documenting carnivore survey results.