Search results for "POPULATION"
showing 10 items of 9945 documents
Social flexibility and social evolution in mammals: a case study of the African striped mouse (Rhabdomys pumilio)
2011
Environmental change poses challenges to many organisms. The resilience of a species to such change depends on its ability to respond adaptively. Social flexibility is such an adaptive response, whereby individuals of both sexes change their reproductive tactics facultatively in response to fluctuating environmental conditions, leading to changes in the social system. Social flexibility focuses on individual flexibility, and provides a unique opportunity to study both the ultimate and proximate causes of sociality by comparing between solitary and group-living individuals of the same population: why do animals form groups and how is group-living regulated by the environment and the neuro-en…
Life history and spatial distribution of the enchytraeid wormCognettia sphagnetorum(Oligochaeta) in metal-polluted soil: Below-ground sink-source pop…
2001
We studied the life history, metal-avoidance behavior, spatial distribution, and population growth of enchytraeid worms (Cognettia sphagnetorum [Oligochaeta]) originating from two sites: one uncontaminated, and another patchily polluted by heavy metals. Effects of patchy soil contamination on populations were studied in microcosms. In uncontaminated soil, worms from the polluted site had lower viability and reduced growth rate as juveniles but higher growth rate as adults compared to worms from the unpolluted site. They were also smaller in size at fragmentation (reproduction). Worms from the polluted site reached a larger population size than worms from the unpolluted site. Hence, worms fr…
Dispersal of Egyptian Vultures Neophron percnopterus: the first case of long-distance relocation of an individual from France to Sicily.
2016
ABSTRACTKnowledge of juvenile dispersal is important for understanding population dynamics and for effective conservation, particularly of geographically isolated raptor populations. Here, we report the first documented case of a long-distance movement of an Egyptian Vulture Neophron percnopterus from the French population to Sicily. This observation opens a new perspective for the conservation of the small and endangered Sicilian population of this species, providing evidence that persistence of the Italian population may be aided by new input from other countries.
Does Population Density Determine the Mating Strategy in Males of the Water Strider Aquarius paludum?
2018
Mating behavior of a large Aquarius paludum paludum (Fabricius 1794) (Hemiptera: Gerridae: Gerrini) population was investigated on several field surveys during the mating season. Both types of mating behavior known for semi-aquatic true bugs were observed in the studied population: aggressive Type I mating for non-territorial males and unaggressive Type II mating for the territorial males. Some males establish individual territories at the lake shores that they defend for around one hour and switch to aggressive mating if they fail to attract a female to mate, while most males remain non-territorial. Radial 1–1.5 meter territories were aggressively defended from other males, conflicts being…
An electrochemical analysis suggests role of gynodioecy in adaptation to stress in Cortaderia selloana
2018
Cortaderia selloana is an invasive, gynodioecious species prevalent in Mediterranean area which contains both female and hermaphrodite specimens in the wild population. Using voltammetric data we show that the female and hermaphrodite specimens exhibit differential electrochemical response. Cortaderia selloana leaves from two different provenances in the Valencia Mediterranean area, Sueca and Cullera (Comunitat Valenciana, Spain), in the surroundings of the Albufera Natural Park, a peculiar ecosystem containing unspoilt dune beaches and forests, were studied to determine correlation of flower morphology with the plant's ability to adapt to stress conditions. Our data suggests that gynodioec…
Gadoria (Antirrhineae, Plantaginaceae): A new genus, endemic from Sierra de Gádor, Almería, Spain
2017
The surprising discovery of a population of a new species of Antirrhineae (Plantaginaceae) has also given rise to the description of a new genus situated in the subtribe Maurandyinae: Gadoria falukei. This is supported by the characteristics of the flower, pollen grains, seeds and capsule, and phylogenetic results based on DNA sequences. The species is endemic from Sierra de Gádor, Almería, Spain. Scanning electron microscopy was used to explore micromorphology of the capsule, indument, and seed and pollen grains ornamentation. Additionally, chromosomal number, preliminary insights on reproductive biology, phylogenetic position within Antirrhineae, ecological data and conservation status of…
Demographic responses to protection from harvesting in a long-lived marine species
2021
Abstract Marine protected areas (MPAs) are usually considered to have positive effects on the recovery of over-exploited populations. However, resolving the extent to which MPAs function according to their conservation goals requires that essential demographic information such as individual survival and population size are quantified. To this end, we analyzed a 16-year replicated mark-recapture study on European lobster (Homarus gammarus, n = 8793) conducted at several protected and unprotected sites in southern Norway, quantifying the impact of MPAs on local population dynamics by means of a “before-after control-impact” study approach (BACI). Lobster survival and abundance were estimated …
Primera cita del endemismo mexicano Agave Difformis a. Berger (Agavaceae) fuera de su área de distribución nativa
2016
17 p., fot., gráf.
Harvesting changes mating behaviour in European lobster
2018
Removing individuals from a wild population can affect the availability of prospective mates and the outcome of competitive interactions, with subsequent effects on mating patterns and sexual selection. Consequently, the rate of harvest‐induced evolution is predicted to be strongly dependent on the strength and dynamics of sexual selection, yet there is limited empirical knowledge on the interplay between selective harvesting and the mating systems of exploited species. In this study, we used genetic parentage assignment to compare mating patterns of the highly valued and overexploited European lobster (Homarus gammarus) in a designated lobster reserve and nearby fished area in southern Nor…
Population Trends of Cave-Dwelling Bats in the Eastern Iberian Peninsula and the Effect of Protecting Their Roosts
2017
Populations trends of cave-dwelling bats in the Eastern Iberian Peninsula and the effect of placing a perimeter fencing around their roosts (to avoid human disturbance on breeding colonies) were evaluated from 1997 to 2014. The species with the highest relative abundance was Miniopterus schreibersii (62.4%), followed by Myotis myotis/blythii (18%), and both populations showed positive trends. On the other hand, Myotis capaccinii (6.2%), M. escalerai (4.8%) and M. emarginatus (0.9%) showed significant, but minor increases, particularly in recent years. Rhinolophus mehelyi (0.2%) displayed no significant trends, while a moderate population decline was recorded for R. euryale (5.1%). Rhinoloph…