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We used 10-km grid data from the Finnish Bird Atlas data and high-resolution data on temperature and rainfall to estimate species richness from climate and environmental variables across spatial scales. We used an ordinary least-squares (OLS) linear-regression model with a quadratic error function to estimate the number of bird species that occur. As a baseline, we used a simple dummy model that estimated the number of species in each grid to be the average number of species over all grids. We found that the best estimator for avian species richness in Finland is the length of the growing season with R2 values from 0.5 to 0.8, depending on the scale. Our results support the energy-water hypothesis, and we suggest that the proximate control of species richness in the present case is productivity, which is in turn controlled by climate. Some of the effects conventionally attributed to scaling may have trivial causes associated with sampling, in particular the completion of missing data as primary units of observation are merged. For broad surveys of patterns, medium resolution may often be adequate and even superior to the highest nominal resolution available.
Fecal sexual estradiol (E2) and progesterone (P4) analyses were conducted on three adult female Formosan black bears in order to establish non-invasive enzyme-linked immunosorbent assays (ELISA) for describing the endocrine profile in a simulated natural breeding environment. Moreover, we investigated whether the Formosan black bear living in subtropical habitats in Taiwan is a seasonal breeder with delayed embryo implantation, ovulation pattern, and maternal perinatal fasting. Our results indicate that mating behavior occurred both before and after the fecal E2 peak of March–June. Fecal P4 concentrations initially increased after mating, then decreased to lower levels, and finally increased again, which is indicative of a delayed embryo-implantation. Fecal P4 levels decreased postpartum. Peaks of fecal P4 levels were also observed in unmated female bears housed with male bears without coitus: their annual fecal P4 levels were higher from winter to spring, similar to the pregnant female bear. Interestingly, only pregnant female bears displayed a physiological state of fasting before and after parturition. These results suggest that Formosan black bears' breeding is seasonal and takes place from spring to early summer. Delayed implantation, maternal perinatal fasting and induced ovulation from male stimulation independent of coital stimulation alone are typical for the species.
In the context of intraspecific competition, the distribution of key resources within a territory could influence the spatial patterns of scent deposition by territory owners, in order to maximise the defensibility of resources and reduce the costs of their defence. We investigated the pattern of spraint deposition by the Eurasian otter (Lutra lutra) in Mediterranean rivers of southern Italy, testing the hypothesis that spraints are concentrated around deep pools bordered by riparian vegetation because these represent important patchy sources of food. Otters strongly selected pools throughout the year, marking the largest ones which probably supported the highest fish biomass. Sprainting sites at pools were also marked more consistently than sites elsewhere on watercourses. A positive correlation between the percentage of spraints next to pools (pool markings) and overall volume of the main prey in otter diet confirmed the importance of pools as sources of prey. These results are consistent with the idea that territory owners should concentrate scent marks on key resources, as an adaptation to the constraints of defending long and narrow territories, which follow the shape of the rivers. Pool marking increased in the warm season and in December–January, but was not correlated with monthly consumption of the main prey, raising the hypothesis of an additional, reproductive function of scent marking. In the absence of specific data on reproduction or births in our study area, this hypothesis needs further investigation.
This study examines the structure and composition of landscapes surrounding ponds with and without great crested newts (Triturus cristatus) — a species that needs an aquatic and a terrestrial environment. We related presence and absence data to 31 local and landscape variables, in a total of 143 areas in south-central Sweden. Land-use variables were measured within the radii of 100 m (local scale) and 500 m (landscape scale) surrounding the ponds. To find drivers of the distribution of great crested newts we used a principal component analysis (PCA) and a logistic regression analysis. Higher amounts of deciduous forest and pasture, together with proximity to deciduous forest seem to be positive for presence of great crested newts. Coniferous forest and mire appear to have a negative effect on the habitat quality for the species. We argue that management of the great crested newt should to a greater extent include the terrestrial habitat. Special attention should also be given to identifying and securing older, deciduous-rich forest in the vicinity of breeding ponds.
We compared trapping and kill efficiency, and by-catch rate of a new reverse-bait trigger rat trap (Ka Mate) with conventional snap traps (Ezeset and Victor), and assessed methods for calculating abundance indices, over 2879 trap nights on Wallis & Futuna and New Caledonia. Ka Mate traps were most effective at killing larger (> 100 g) rats whereas Ezeset traps had the best capture rates of smaller (< 100 g) rodents. Victor mouse traps caught rodents up to 50 g, but were no more efficient than rat traps. Proportions of live captures were similar for Ka Mate and Ezeset traps, but the mass threshold for live rats in Ezeset traps was much lower than that of the Ka Mate traps. Ka Mate traps had much lower non-target by-catch rates than Ezeset traps in habitats free of land crabs. We developed a new rodent abundance index to standardise results of different trap systems.