Marking quilled animals for individual recognition may be challenging. This is particularly true for European hedgehogs Erinaceus europaeus, whose defense mechanism involves the concealment of muzzle and underparts. Heat-shrink tubes have been widely used to mark quills, but they do not adapt to the morphological structure of the spines and are rapidly lost, thus reducing method effectiveness. We adapted a cheap and ethical method used to mark crested porcupine quills, which involves the use of colored adhesive tapes applied to quills. The retention period of this marking technique lasts up to 9 months, allowing short-term field studies and possibly dispersal distances measurements. The method could be improved by doubling the number of marked spines and by reapplying adhesive tape at every recapture event. Moreover, the use of a marking code can be obtained by subdividing the body of the hedgehog into six body areas, to increase the number of marking possibilities, through the combination of tape colors and body areas.
We present a new method of collective marking (rhodamine B) of small mammals that can be used under natural conditions. We examine the acceptance of marked baits, detection and persistence of the signal on the different kinds of hairs of two small species of rodents. Rhodamine B was ingested by captive animals and their hairs were dyed a fluorescent red coloration and observed over more than 150 days. Preliminary results obtained under field conditions tend to demonstrate that winter and summer movements could be detected by this technique. This new collective marking technique may be of great interest to study population turnover and movements of small mammals between habitat patches; it may represent an important method of assessing connectivity and permeability of landscapes by small mammals.
Lynx Lynx lynx maternal behaviour and dispersal pattern were studied by radio -telemetry in the Białowieża Primeval Forest, E Poland from 1992-1995. From June-July, 2 females with kittens used 1-4 dens per month, for 5 to 33 days each, Consecutively used dens were 1-3 km apart and were located in inaccessible places. Female movements were concentrated around the den at this time, Mothers left their kittens and returned to them, on average, 3 times per day. Mean time of female's absence from the den was 4 h 20 min. Mean den attendance averaged 4 hours. In August, kittens began to accompany their mother. At this time, each den was used for 2-3 days only and the distances between consecutive dens were 0.5—2 km. Dens were situated in places where a female killed large prey. In August, a female spent an average of 12 h 50 min with kittens, alternating with 4-h of absence. Subadults dispersed at 9-11 months of age, immediately after separation from their mothers. Four subadult males dispersed for 11, 39, 62 and 129 km from their natal ranges. Two subadult females dispersed for 5 and 9 km. Lynx that moved the farthest distances covered most of their routes during the first two months of dispersal, when they moved 20-32 km/month, compared to 3-11 km/month in the later period. Distant emigrations of two adult lynx (55 km by a male and 120 km by a female) were also recorded. Directions and routes of lynx dispersal and emigration were related to the contemporary distribution and availability of woodlands and forest corridors.
The development of our understanding of population dynamics over the past 50 years is reviewed from a personal perspective. An early emphasis on population vital rates was superceded by recognition of the importance of the specific community context of focal populations, and most recently has in turn been enriched by a landscape perspective. Certain basic principles are outlined including the value of a systems context for population analyses, the power of a dual mechanistic and contextual perspective, and the inevitability of density control in a finite biosphere. Numbers are determined by the balance of two complex parameters: p - the per capita growth promoting (enhancing) forces, and s - the per capita growth suppressing forces. Multiple factor explanations of demographic behavior are therefore to be expected, as well as temporal and spatial variations in them. An appreciation for the potential role of dispersal as a population vital rate led to the development of metapopulation theory. A renewed understanding of the role of community context in population dynamics provoked the realization that a multi-factor approach was required. This in turn allowed us to reconcile the reality of local demographic complexity with global generalizations. Finally, the introduction of landscape ecology into demographic thinking added many new insights. It is now appreciated that a spatially explicit mosaic of habitat patches, edge effects, corridors, and even the proportion of favorable to marginal habitats can all be critically important factors in influencing population dynamics.
Habitat and spatial organisation of 11 radio tagged Eurasiani lynxes Lynx lynx Linnaeus, 1758 were studied in a low-density (ca 0.3 ind/100 km ) population in a boreal-alpine environment with low and temporally varying densities {< 180 ind/100 km in winter) of ungulate prey, primarily roe deer and semi-domestic reindeer. The use of habitat measured as 4 biome categories ranked from south boreal to alpine influenced mountain vegetation did not vary seasonally, but lowlands were much preferred to alpine habitats. Adult males moved almost 3 times farther per day in linear distance (x = 5.9 km, n = 3) than did females with kittens ix = 2.0 km, n = 4) or subadult females (x = 2.5 km, n = 6; p = 0.002). Subadults (n = 5) dispersed 42 ± 13 (x ± SE) km during the first 9 months of independence, but often visited their natal range during the first year on their own. Adult lynxes roamed over very large annual ranges [males: 1906 ± 387 km (n = 4), females: 561 ± 102 km2 (n = 6)J that took > 5 days to pass through, independently of sex. The oniy male monitored over more than 1 year maintained 2 separate home ranges each year. The larger home ranges and the possible tendency towards less defined territory boundaries than previously reported for the species, may be caused by the lower prey and population densities, though culling of adult individuals may also have played a role by continuously creating empty gaps in the territorial mosaic.
Collembola often play an important controlling role in the interrelationship between arbuscular mycorrhizal fungi (AMF) and host plants. However, there are little data to prove AMF dispersing ability of Collembola. In our experiment Folsomia candida (Willem) did not consume the spores of Glomus mossea (Nicol. and Gerd.) and G. intraradices (Schenck and Smith), but Sinella coeca (Schött) consumed 45% of the G. mossea spores and 71% of G. intraradices spores. Both species were able to disperse mycorrhiza in the soil, but the efficiency of dispersal was different. F. candida carried the infection more effectively than S. coeca, in spite of the fact that F. candida did not consume the spores in the food choice experiment. The total plant biomass was 23% higher in the presence of F. candida and 8.5% higher in the presence of S. coeca than in the control treatment without Collembola. The water content of the plants was also a little higher in the presence of both Collembola species (about 10%) than that of the control plants, but this difference was not statistically significant. Collembola improved the dispersion of the AM fungi, therefore enhanced the nutrient and water uptake of the plant.
When conditions deteriorate, freshwater cladocerans from the genus Daphnia switch to production of diapausing eggs encased in chitinous shells called ephippia. Ephippia may serve for temporal escape and recolonisation of the habitat or for geographical dispersal and colonisation of other habitats. While dormancy and dispersal of ephippia have been well studied, initial factors determining the fate of the ephippia have remained unknown. We first consider the fate of an ephippium that sinks to the bottom of the water body, where it enriches the egg bank present in the sediments. We then discuss the potential and evidence for dispersal of ephippia, which is probably facilitated by their flotation on the water surface. Finally, we concentrate on the moment of the release of the ephippium showing a likely mechanism that determines its further fate – temporal or spatial dispersal – and we demonstrate it to be accomplished through maternal behaviour.
The alvarezsauroid theropod Linhenykus monodactylus from the Upper Cretaceous of Inner Mongolia, China is the first knownmonodactyl non−avian dinosaur, providing important information on the complex patterns of manual evolution seen in alvarezsauroids. Herewe provide a detailed description of the osteology of this taxon. Linhenykus shows a number of fea− tures that are transitional between parvicursorine and non−parvicursorine alvarezsauroids, but detailed comparisons also re− veal that some characters had a more complex distribution. We also use event−based tree−fitting to perform a quantitative analysis of alvarezsauroid biogeography incorporating several recently discovered taxa. The results suggest that there is no statistical support for previous biogeographic hypotheses that favour pure vicariance or pure dispersal scenarios as explana− tions for the distributions of alvarezsauroids across SouthAmerica, NorthAmerica andAsia. Instead, statistically significant biogeographic reconstructions suggest a dominant role for sympatric (or “within area”) events, combined with a mix of vicariance, dispersal and regional extinction. At present the alvarezsauroid data set is too small to completely resolve the biogeographic history of this group: future studies will need to create larger data sets that encompass additional clades.
Studies dealing with the individual survival of birds in open populations usually estimate survival according to capture-recapture models like the Cormack-Jolly-Seber (CJS). In fact, these models estimate local apparent survival (φ), which is a combination of the probabilities of true survival (S) and site-fidelity (F), i.e. death and emigration are confounded. These S and F parameters can be estimated by using 'robust' models (e.g. Barker's model), which use additional resighting and dead reports data. We aim to compare the results (and associated biological implications) obtained by analysing juvenile and adult survival in a Polish urban population of Blackbirds Turdus merula using both the CJS and Barker models. Our CJS models estimated high φ values for both juvenile and adult birds (0.48 and 0.62, respectively). The lower scores for juveniles could be interpreted as low juvenile overwintering survival. By fitting Barker models to the same dataset we determined that juvenile site fidelity was lower than that of adults (0.91 and 0.93, respectively), so natal dispersal was slightly greater than breeding dispersal. The high fidelity causes similarity between apparent survival and true survival parameters (S: 0.51 for juveniles, 0.64 for adults). The results are comparable with data from other urban populations. Thus, using robust models certainly allows one to reduce the noise of movements confounding and/or masking survival probabilities, but one can also determine the individual or environmental variables affecting any of them separately.
Spatial distribution and genetic variation of a population of Sorbus chamaemespilus (L.) Crantz and putative hybrids between S. chamaemespilus, S. aria and S. aucuparia growing in the nature reserve Skalnä Alpa (central Slovakia) were studied. The analysis of spatial patterns using Ripley's K-function revealed a significant clustering of the adults of both S. chamaemespilus and hybrid taxa at distances up to ~15 m and a strong affinity between both taxonomical groups, indicating similar ecological requirements. Bivariate point-pattern analysis considering cardinal direction showed that juvenile individuals of S. chamaemespilus are clustered around the adults up to the distance of ~2 m, whereas in hybrid taxa with larger and more dense crowns, juveniles are clustered at distances more than ~3 m from the adults. The analysis of genetic variation in a subset of adult shrubs using 4 nuclear microsatellite loci revealed that unlike expected, there was no variation in S. chamaemespilus but several genotypes were found in the group of hybrid taxa. Implications for the reproduction system and conservation of the investigated taxa are discussed.
The world-wide research on ship-aided dispersal of marine organisms and invasions of non-indigenous species focuses primarily on the plankters, which show the greatest potential for invading new areas and establishing viable populations in them, either in the water column (holoplankton) or on the bottom (meroplanktonic larvae of benthic species settling on the sea floor). As meiobenthic animals usually lack a pelagic larval stage in their life cycle, no biological invasion study has, to our knowledge, ever specifically targeted marine transport as a means of meiofaunal dispersal. Here we present a set of data showing that the sediment deposited in a ship’s ballast water tank does support a viable meiobenthic assemblage. We examined 0.015-dm3 aliquots of a 1 dm3 sample from a c. 1.5-cm thick layer of sediment residue in the ballast tank of MS Donnington, brought to the ‘Gryfia’ Repair Shipyard in Szczecin (Poland). The samples were found to contain representatives of calcareous Foraminifera, hydrozoans, nematodes, turbellarians, harpacticoid copepods and their nauplii, and cladocerans, as well as meiobenthic-sized bivalves and gastropods. Nematodes proved to be the most constant and most numerous component of the assemblage. The sediment portions examined revealed the presence of 1–11 individuals representing 11 marine nematode genera. The viability of the meiobenthic assemblage was evidenced by the presence of ovigerous females of both nematodes and harpacticoids. Survival of the meiobenthos in shipborne ballast tank sediment residues may provide at least a partial explanation for the cosmopolitan distribution of meiobenthic taxa and may underlie the successful colonisation of new habitats by invasive meiofaunal species.
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