Influence Of Habitat Conditions Research Articles

Maternal behaviors influence survival of ungulate neonates under heavy predation risk.

Predators impose top-down forces on prey populations, with the strength of those effects often varying over space and time and among demographic groups. In ungulates, predation risk is typically greatest for neonatal offspring, with some suggesting that predators can key in on adult activity to locate hidden neonates. However, few field studies to date have been able to directly assess the influence of maternal care on ungulate neonate survival. Using a population of white-tailed deer under heavy coyote predation pressure, we tested the maternal dispersion hypothesis, which suggests the dispersion of maternal activity temporally and spatially attenuates risk of predation for ungulate neonates during this vulnerable altricial phase. We compared support for this hypothesis with more commonly tested hypotheses regarding the influence of habitat conditions and intrinsic factors on neonatal survival. Fawn survival to 16 weeks was 27.7%, with coyotes accounting for 59% of fawn mortalities. In support of our maternal temporal diffusion hypothesis, we found that neonatal survival decreased as more maternal visits (proportionally) occurred at night. The only other significant (p < .1) predictor of fawn survival was birth timing, with fawn survival decreasing as the season progressed. Given that fawn survival declined as the proportion of nighttime visits increased, and that wild pig presence and human disturbance can push doe and fawn activity toward nocturnal hours, additional research is needed to determine whether managing pig and human disturbance can decrease fawn mortality. More broadly, given the importance of recruitment in ungulate population dynamics, our finding opens a potentially important new line of inquiry on how maternal behaviors influence predation risk in large animal predator-prey ecology.

Особенности роста и структуры древесины сосны на вырубке и под пологом древостоя в условиях Республики Карелии

The intraspecific variability of the anatomical and hydraulic characteristics of xylem in the undergrowth in Scots pine (Pinus sylvestris L.) has been assessed during natural regeneration in the felling areas and under the canopy of a middle taiga blueberry pine forest in the conditions of the European North (Republic of Karelia). The influence of habitat conditions on the formation of structural elements of wood cells has been revealed. In felling areas under conditions of higher illumination, air and soil temperatures, the transition of pine undergrowth to the category of large with a height of more than 1.5 m occurs at the age of 6 years, whereas under the canopy of a mature stand the undergrowth reaches this category no earlier than 15 years. At the same time, in the 1st decade of growth under felling conditions, the growth of pine in diameter has been 4 times higher than that of pine under the canopy of a mature stand due to the formation of a larger number of rows of tracheids in the early and late zones. In addition, the pine undergrowth in the felling area has the highest potential hydraulic conductivity of the xylem, and, on the contrary, the lowest specific density of tracheids, the basic wood density and late wood content relative to the pine undergrowth under the canopy of the stand. The latter exhibited a significant decrease in the structural and functional characteristics of wood, with the exception of the thickness of the cell membranes of late tracheids. In the interanual dynamics, more stringent linear regression dependencies between the indices of early and late tracheids have been observed in pine undergrowth under the forest canopy. The results obtained indicate a greater correspondence of the environmental conditions in the felling area to the optimum for the growth and formation of wood of young pine trees relative to the conditions under the canopy of a mature blueberry pine forest. Inhibition of the growth activity of undergrowth under the canopy occurs due to high intraspecific competition from the dominant pine stand for light, moisture and soil nutrition.

Characterization of the size and spatiotemporal structure of the cenopopulation Caragana arborescens Lam. in the forest park of Yekaterinburg

The article is devoted to the study of the dimensional and space-time structure of Caragana arborescens Lam. in various ecological and cenotic conditions in the forest park named after. Foresters of Russia in Yekaterinburg on the basis of population and organismal parameters. For the first time, a quantitative characteristic of the manifestation of organismal indicators in each ontogenetic state of the caragana was obtained. Regularities in the manifestation of traits depending on the ontogenetic conditions of plants and forest type, as well as features of changes in traits that occur during the growth of individuals during the life period, are revealed. Features of the average values of the manifestation of traits in ontogenetic states can be associated with the number of individuals of a given state in the corresponding samples, while there is an influence of habitat conditions. A one-way analysis of variance, in which the habitat type of a coenopopulation fragment was a factor, showed a significant effect of the factor for traits of crown height and width. Significant differences in these traits of the habitat of the mixed herb meadow from other habitats and the reduced values of the traits in the forb pine forest are explained by the predominance of medium generative individuals in the first case, and juvenile individuals in the second. The ability of the species to successfully adapt in fragmented and urbanized areas affected by recreational impacts and other forms of pollution and survive in a wide range of environmental conditions has been established.

ОПЫТ ПРИМЕНЕНИЯ МЕТОДОВ СТАТИСТИКИ ДЛЯ ОЦЕНКИ ТАКСОНОМИЧЕСКОГО И МОРФОЛОГИЧЕСКОГО РАЗНООБРАЗИЯ РАННЕМЕЛОВЫХ БЕЛЕМНИТОВ СЕВЕРНОЙ СИБИРИ

The paper considers the application of statistical methods for assessing variations in the taxonomic diversity of belemnites using the example of the Early Cretaceous representatives of the family Cylindroteuthididae from northern Siberia. Global and regional factors influencing the biodiversity dynamics were taken into account. A composite curve of the biodiversity of Ryazanian–Valanginian belemnites in northern Siberia was constructed using the methods of rarefaction and extrapolation of data. Using graphic techniques, the influence of habitat conditions on the predominant morphology of belemnite rostra is shown. Based on indices of similarity and difference, an assessment of the pattern of changes in taxonomic diversity over time was made.

The Influence of Habitat Conditions on the Properties of Pinewood

This article starts a series of articles on dependences between the conditions of the growth of trees in forests and the technical aspects and directions of using the raw material obtained from these trees. This is a key feature for wood purchasers because it determines the efficiency of production and directly affects the final financial result of their activity. Wood represents an environmentally sustainable and renewable material, which is a widely available raw material on the market and must meet specific quality and strength requirements. These parameters indicate the utility values of wood and the possibilities of its use. One of the factors influencing the properties of wood is the type of the forest habitat it comes from. In order to determine this influence, tests were carried out to show how tree growth conditions affected changes in the density and strength of raw wood. The assumption (hypothesis) about the correlation between the static bending strength of Scots pine (Pinus sylvestris L.) wood and the forest habitat was verified on four forest types, i.e., fresh coniferous forest (FCF), fresh mixed coniferous forest (FMCF), fresh mixed forest (FMF) and fresh forest (FF). The properties depend largely on the wood structure, its origin on the cross section and the length of the stems. The raw material selected for the study came from Scots pine trees growing in forests in central Poland. The study confirmed the influence of the habitat on changes in the density and strength of pinewood. There was a correlation between the habitat FMCF and the quality parameters of the raw material, which reflected the wood structure r = 0.775; p &lt; 0.05.

New association between Spodoptera frugiperda J.E. Smith (Lepidoptera: Noctuidae) and native natural enemies: Bioprospection of native natural enemies as biological control agents

Fall armyworm (FAW) Spodoptera frugiperda is an invasive pest that enters Indonesia which can pose a serious threat to the continued production of maize and other crops. This condition is exacerbated if there are no natural enemies who can control the pests. This study aims to explore potential native natural enemies to control the population of FAW in Indonesia and the influence of habitat conditions on the distribution and population of natural enemies. The research was conducted in seven sub-districts in Bogor and three plots were selected from each district. Observation of natural enemies was carried out directly by collecting samples of eggs and larvae of FAW which attacked maize with the transect method on 200 individual plants. The samples collected will be rearing until the parasitoids emerged. We Collected seven genera of parasitoids that were associated with FAW: Apanteles, Charops, Euplectrus, Microplitis, Telenomus, Trichogramma, and two types of predators: ground beetles and Assasin bug. The highest parasitization rate of egg parasitoid was 93.4% while for larvae parasitoid was 12.44%. In conclusion, Telenomus and Microplitis are native parasitoids that can be used as potential natural enemies to control the S. frugiperda population in the field.

LINEAR AND WEIGHT GROWTH OF THE WALLEYE IN THE TEREK-CASPIAN FISHERY SUBDISTRICT

The article presents the linear and weight growth of the pikeperch in the coastal and inland waters of the Terek-Caspian fishery subdistrict. The dynamics of the linear and weight growth of the pikeperch on the Daghestan coast of the Caspian Sea and in the inland waters of Daghestan in the long-term aspect is shown. It was revealed that the average length and weight of the same-age pikeperch in different years are at a close level, which indicates stable conditions of living, feeding and food supply in the study period. The formation of the pikeperch populations in the Terek-Caspian region is influenced by the dynamic environmental conditions (sea level, hydrological and hydrochemical regime, water pollution). At the same time, the influence of habitat conditions is not critical and does not lead to significant changes in the qualitative and quantitative characteristics of the pikeperch and its forage objects in modern conditions.

Influence of habitat conditions on group size, social organization, and birth pattern of golden langur (Trachypithecus geei).

We studied endangered golden langurs in fragmented and altered habitats to understand the consequences of habitat conditions on group size, social organization, and birth seasonality. We selected 12 groups inhabiting forest edge and forest core of Chakrashila Wildlife Sanctuary (henceforth Chakrashila WLS) and adjoining the Abhaya rubber plantation. Each group was monitored every month from May 2013 to September 2016 and recorded the age-sex of individuals in the group. The births were recorded with the individual identity of females in five focal groups. The overall group size of golden langur was 11.3 ± 3.5SD, and ranged between 5 and 18. The mean group size in forest core, forest edge, and rubber plantation differed significantly. We recorded a total of 46 births in 12 groups across the three different habitats. The number of infants correlates positively with adult females and group size across all the 12 groups for all the years. The number of births that occurred in all the months varied significantly across the months. Births occurred in all the months but peaked between May and September (82.6%). The mean number of births positively correlated with mean monthly rainfall. Mean inter-birth interval was 24.5 ± 1.6SD months that did not vary between the females. It therefore appears that group size is sensitive to forest type, and births are positively related to social and environmental factors. The behavioral parameters may influence life-history traits if continuous habitat alteration persists.

The influence of habitat conditions on the abundance and selected traits of the rare medicinal plant species Filipendula vulgaris Moench

The research on the influence of habitat conditions on the traits of Filipendula vulgaris were carried out in 2015 and 2016 in abandoned wet meadows (Patches I and II) and frequently disturbed, calcareous grasslands (Patches III and IV). The cover of vas- cular plants and cryptogams was much greater and soil pH was remarkably lower in the meadow patches than in the grassland ones, whereas the height of neighbouring plants and soil humidity gradually decreased from Patches I to IV. The meadow populations of F.vulgaris showed much lower abundance as well as lower total relative abundance of seedlings and vegetative rosettes compared to the grassland populations due to the scarcity of safe sites for offspring recruitment. Rosettes presenting solely spatial variability were characterised by a significantly greater number of short leaves in the meadow populations or not numerous, large leaves in the grassland populations. The similar (in consecutive years) height of generative shoots, the number of cauline leaves, inflorescences and flowers gradually decreased at subsequent study sites. The results may provide the basis for further studies on the impact of habitat conditions and the size of aboveground parts of F. vulgaris on the content of bioactive compounds in plant material.

Hemolymph cholinesterase activity in the Mussel Crenomytilus grayanus (Dunker, 1853) that was exposed to adverse natural and anthropogenic conditions

The influence of habitat conditions on the activity, the structure of the substrate specificity (the ratio of the substrate hydrolysis rates), and the kinetic parameters of substrate hydrolysis due to the effect of hemolymph cholinesterase of the mussel Crenomytilus grayanus was studied. Mussels were collected from areas that are influenced by seasonal and stationary upwelling, as well as from a polluted area. Upwelling and anthropogenic pressure were shown to alter the structure of hemolymph cholinesterase substrate specificity in mussels, up to complete loss of the ability to catalyze the hydrolysis of propionyland butyrylthiocholine. It was established that during the seasonal upwelling the efficiency of the cholinergic process in mussels is provided by a wide range of effective concentrations of the substrates and by decreasing their affinity to the enzyme. Under the conditions of chronic anthropogenic pollution, the cholinesterase of the mussel hemolymph loses its ability to hydrolyze substrates other than acetylthiocholine.

The dimorphic queens of Polyrhachis australis (Hymenoptera: Formicidae)

AbstractThe formicine weaver ant Polyrhachis australis Mayr is one among many species of ants that have queens of two more or less distinct sizes, usually referred to as microgynes and macrogynes. The current consensus explains this phenomenon in terms of alternative strategies of dispersal and reproduction: microgynes typically walk to found new nests locally, macrogynes typically fly to found new nests farther afield. This study addressed four questions bearing on that interpretation: is the dimorphism complete (without intermediate sizes) or continuous in P. australis? Does the proportion of macrogynes correlate with the number of queens in the nest? Does the microgyne/macrogyne proportion vary over time? And are brachypterous individuals always microgynes? The implications of these questions concern the fitness status of the intermediate size individuals, the relative fitnesses of the two main morphs as the number of queens diminishes, the influence of habitat conditions on the production of the morphs, and the dispersal behaviour of microgynes. The size distribution of P. australis queens was incompletely bimodal, with some individuals of intermediate size. The proportion of macrogynes in nests increased with decreasing numbers of queens in nests, suggesting that macrogynes do better in whatever contests take place between queens during the ergonomic stage. Between 2009 and 2014, the proportion of macrogynes in nests fell from about 1 in 3 or 4, to less than 1 in 11, perhaps reflecting a differential production of queen morphs in saturated and unsaturated habitats: it profits a colony to produce more microgynes and fewer macrogynes when local conditions favour the easy founding of new nests by walking. Brachyptery was centred on the smallest microgynes, consistent with their assumed mode of dispersal for which wings are not needed.

Changes in the chlorophyll a and b content in different-aged leaves of Spergula vernalis Willd.

The result are reported of investigations on the seasonal variations in the chlorophyll a and b content in the successive leaf tiers of &lt;i&gt;Spergula vernalis&lt;/i&gt; Willd. growing in two different dune habitats. It was endeavoured to determine the influence of habitat conditions on the concentration of green pigments. The eventual relationship between their amount and the production of organic matter by the plants is discussed.

Subsistence Shell Fishing in NW Santa Isabel, Solomon Islands: Ethnoarchaeology and the Identification of Two Polymesoda (Solander 1786) Species

The large mangrove bivalves of the Polymesoda genus represent a major contributor to Indo-Pacific marine resource economies and are frequently recovered from archaeological deposits in this region. Unfortunately, malacologists have long struggled to accurately distinguish between Polymesoda expansa and Polymesoda erosa—the two most prolific and widely distributed species of the Polymesoda genus. For archaeologists this scientific inaccuracy has likely hindered the correct identification of shell remains (casting possible doubt over reconstructions of prehistoric marine subsistence economies) and has led to taxonomic confusion and inconsistencies within archaeological literature. This paper presents new scientific data on P. erosa and P. expansa obtained through ethnoarchaeological investigations of contemporary shell fishing in northwestern Santa Isabel, Solomon Islands. Through interviews with female shell fishers, size analyses of live subsistence shellfish hauls and participant observation of gathering episodes, new criteria for improving the reliability of identification and interpretation of archaeological shell remains are presented. Other outcomes of this research include new insights into the influence of environmental and habitat conditions on shell morphology, which contribute new ecological information on P. erosa and P. expansa that is broadly useful to malacologists (for better understanding distribution, settlement, and survival of species within the mangrove habitat) and archaeologists (for better understanding the influence of habitat conditions on radiocarbon dating of marine shell remains).

The influence of habitat conditions on the performance of two invasive, annuals — Impatiens glandulifera and Bidens frondosa

The investigations of habitat conditions on the variability of selected population features in the two invasive, annuals with different life-history traits were conducted in the years 2008–2010, in the Polish part of the Carpathian Mountains in communities characterized by the gradual decrease of light availability. The individuals of Impatiens glandulifera were surveyed along roadsides, in willow thickets, as well as inside and along the edges of the riparian forest, whereas the individuals of Bidens frondosa were observed in riverside gravels characterized by a different species composition. Each year, the number and density of individuals (stems) occurring in the particular sites were examined, as well as the height and the fruit production in 30 randomly chosen stems were surveyed. Moreover, the number of seeds per fruit, the diaspore dimensions and the seedling recruitment in laboratory conditions were examined during each season. As the values of height of individuals, number of fruits per stem, number of seeds per fruit, as well as the seedling abundance in some groups were not consistent with the normal distribution and the variances were not homogeneous, the non-parametric Kruskal-Wallis test was used in statistical analyses.

Spatial heterogeneity in habitat selection: Nest site selection by greater prairie‐chickens

AbstractEcological relationships of animals and their environments are known to vary spatially and temporally across scales. However, common approaches for evaluating resource selection by animals assume that the processes of habitat selection are stationary across space. The assumption that habitat selection is spatially homogeneous may lead to biased inference and ineffective management. We present the first application of geographically weighted logistic regression to habitat selection by a wildlife species. As a case study, we examined nest site selection by greater prairie‐chickens at 3 sites with different ecological conditions in Kansas to assess whether the relative importance of habitat features varied across space. We found that 1) nest sites were associated with habitat conditions at multiple spatial scales, 2) habitat associations across spatial scales were correlated, and 3) the influence of habitat conditions on nest site selection was spatially explicit. Post hoc analyses revealed that much of the spatial variability in habitat selection processes was explained at a regional scale. Moreover, habitat features at local spatial scales were more strongly associated with nest site selection in unfragmented grasslands managed intensively for cattle production than they were in fragmented grasslands within a matrix of farmland. Female prairie‐chickens exhibited spatial variability in nest site selection at multiple spatial scales, suggesting plasticity in habitat selection behavior. Our results highlight the importance of accounting for spatial heterogeneity when evaluating the ecological effects of habitat components. © 2013 The Wildlife Society.

Preliminary phytochemical studies for the quantification of secondary metabolites of medicinal importance in the plant, Acalypha fruticosa Forssk

The medicinal plant, Acalypha fruticosa Forssk for the treatment of dyspepsia, stomachache, fever, jaundice, skin diseases and even as an antidote is generally distributed in different environments of tropical region in Coimbatore district of Tamil Nadu. However, its occurrence is more common in lower hills of Western Ghats and other habitats in this region where the soil is stony with low moisture. So far, there was no study on the influence of habitat conditions on the change in the content of secondary metabolites of medicinal importance in this plant. Hence to know the changes in the content of such secondary metabolites in the leaves of A. fruticosa, the present study was undertaken in three different habitats. Thin layer chromatography revealed the presence of phytochemical compounds viz., alkaloids, flavonoids and saponins in the leaves of all the three populations. Further the content of all these compounds are found to be higher in the population of dry habitats.

The Influence of Habitat Conditions on the Properties of Eggs Proteins of Silver Carp

The Influence of Habitat Conditions on the Properties of Eggs Proteins of Silver Carp