Search
Saiga and outgroup specimens were subjected to X-ray computed tomographic (CT) imaging, gross dissection and skeletonization. The nasal cavity of saiga is characterized by an enlarged nasal vestibule and basal conchal fold. Many structures (e.g. turbinates, lateral cartilages, mucosal folds, nasolacrimal duct) are retracted caudally to a small area in the caudodorsal part of the nasal cavity proper. The enlarged vestibule is associated laterally and ventrally with paired sacs. The nasal septum is largely membranous and contains a large patch of cavernous tissue that serves as a dynamic baffle modifying the flow of inspired air...
In this study we explore the factors influencing inferred poaching behav- iour of the Critically Endangered saiga antelope (Saiga tatarica) in six communities in three countries of the former Soviet Union. We show that local people have a good understanding of the species' status and positive attitudes towards its conservation, regardless of their household's inferred poaching status. Poaching is a low prestige occupation, and our analyses suggest that it is carried out by poor, unemployed households who have the means to hunt. These results are consistent for all villages.
Censuses are an important component of monitoring the status of
wildlife populations. Different techniques are used for different
species, on account of their specific biological characteristics.
The European population of the saiga antelope (Saiga tatarica)
inhabiting northwest Caspian Lowlands (eastern part of the Republic
of Kalmykia and south-western part of the Astrakhan Region) is in a
critical condition.
In order to describe the population dynamics of the saiga antelope adequately, a discreet time, stochastic age-structured model is needed. Management strategies investigated are: taking a proportion of the population or a constant number of individuals; selecting the individuals killed by age and sex or harvesting in the proportions found in the population; harvesting every year, every other year or only in years with a good climate. These options are chosen with reference to the management strategies that were in place before the collapse of the Soviet Union.
Satellite tracking of gazelles proved their ability to move long distances and provided details of their migration routes. In Omnogobi, the NDVI of the summer range was higher than those of annual and winter ranges during summer, but from October to November the NDVI of the summer range was lower than annual or winter ranges. The shift in NDVI values between summer and winter ranges corresponded with seasonal migrations of gazelles.
Despite the potential effects of numerous sex-skewed harvests, in this paper we investigate one potentially deleterious effect of sex-skewed harvests. Both theory and experimental data suggest that male ungulates are limited in their absolute ability to inseminate females.
Using a Leslie-Matrix model and published data on impala, we show that the interaction between sperm limitation and harvests with highly male-biased sex ratios can lead to greatly reduced female fecundity (defined as the number of young born) and population collapse. These results are robust and suggest that present methods of harvesting may not be optimal or viable in the long term.
The battle over access to mates is perhaps one of the most extreme conflicts in evolution. Male to male conflict sometimes becomes so intense that it can result in the death of all males in a population. For example, in marsupials of the genera Antechinus and Dasyurus, the diseases that appear to follow from excessive investment in mating can wipe out all males in the population after the mating season. This is not harmful to population persistence, however, as inseminated females produce new males. If males can invest so much in sex that they eventually kill themselves, to what extent will they harm a potential mate?