Comparing different environmental variables in predictive models of bird distribution

The response variable (often the presence of a species) in predictive habitat models relies on a set of environmental predictors. Among all known environmental predictors, vegetation has the most effect on species abundance and on their habitat preferences, due to the wide range of necessary resources that it provides for the survival of bird species. However, other predictors, in turn, affect bird distribution, and some-times they play a more important role in habitat selection, depending on the natural history and ecological needs of the bird species. In this regard, different analyses have been conducted to predict the distribution, and define habitat suitability (such as discriminant function analysis, General Linear Models, and ANOVA). In this study, all three analytical designs were used to investigate the relationship of seven bird species to the major environmental gradients in the study area, to find out the significance of each of these factors on habitat selection. GIS has been used to prepare spatial distributional data, and to overlay and calculate different aspects of the environmental factors. The results suggest that potential individual habitat patches play a small role compared to the landscape (entire corresponding habitat patches), when considering vegetation. The influence of built-up areas is significant for all the species, and the proximity to the sea shore is very significant for at least one of the species, however, it is not neutral for all other species.     

Dynamics of Habitat Distribution in Birds Differing in the Level of Site Tenacity

The dynamics of habitat distribution in two bird species differing in the level of site tenacity—willow warbler (relatively tenacious) and little bunting (more flexible)—were studied at the boundary of the northern taiga and forest–tundra zones over ten years. The distribution pattern proved to be more uniform in the willow warbler than in the little bunting. Both species occupied their habitats according to a well-known scheme: initially, the birds settled in their favorable floodplain habitats and later; when their abundance increased, in less preferable habitats (terraces above the floodplain, moss bogs, and the tundra). In the case of willow warbler, the process of occupying the floodplain was stepwise: bird density increased sharply, remained at the same level in the next year, then increased again, etc. In the case of little bunting, the degree of floodplain occupation by birds remained high, except for the years when high spring floods interfered with bird settling.     

Abundance of orchids on calcareous grasslands in relation to community species,environmental, and vegetational conditions

The abundance of Orchidaceae on three calcareous grasslands is studied in relation to floristic composition, environmental and vegetational factors and plant traits (ecological and life forms). The aims are: (i) to identify a group of species that is significantly correlated with the abundance of Orchidaceae or with individual species of orchids on calcareous grasslands; (ii) to study the relationship between traits associated with habitat specialisation, community life forms and the abundance of orchids; (iii) to identify the main environmental and vegetational predictors of the abundance of orchids. A shortlist of species is found to be significantly correlated with the abundance of total orchids, Orchis pauciflora and O. morio. The life forms of the community species do not show any correlation with the orchids, with the exception of Orchis pauciflora, which tends to increase in communities rich in hemicryptophytes and poor in annual species. Analyses of Orchis morio seem to suggest that it has a high level of ecological tolerance. The most important predictors of the abundance of orchids are the substrate reaction (basic) and arid grassland with low herbaceous vegetation cover (i.e. high soil reaction and luminosity values, positive correlation with the cover of lichens and rockiness, negative correlation with tree cover and herbaceous layer). The least favourable sites were the least basic and most superficial and arid sites.     

Long-Term Changes in the State of Gonads in Sea Urchins Strongylocentrotus intermediusfrom Amur Bay,the Sea of Japan

The state of gonads was analyzed in sea urchins Strongylocentrotus intermediuscollected in Amur Bay (Peter the Great Bay, the Sea of Japan) in August 1984, 1985, 1989, and 1997 at five stations: Skrebtsov Island (1), Sportivnaya Harbor (2), Cape Tokarevskii (3), Alekseev Bay on Popov Island (4), and Verkhovskii Islands (5). The first three stations were in the polluted inshore zone of Vladivostok; stations 4 and 5 were in the open (insular) part of the bay, remote from the main sources of pollution. The state of gonads of sea urchins collected in different years and areas strongly varied with respect to gonad index (GI), gonad maturity index, and indices of pathological changes in gonads. As compared with the data obtained in 1984, 1985, and 1989, the values of GI increased in sea urchins from stations 1–3 and decreased in sea urchins from stations 4 and 5. Although GI values were high, the indices of gonad maturity in animals from the coastal zone were very low. In general gonad maturity in sea urchins from the Amur Bay was lower in 1997 than in the previous years. The correlation analysis of long-term data revealed no positive correlation between the values of GI and gonad maturity index in sea urchins from stations 1–4. Histopathological changes were more serious in sea urchins from stations 1–3. In 1997, the indices of pathological changes in the gonads of sea urchins from the insular zone (stations 4 and 5) were higher than in the previous period (1984–1989). The influence of various ecological factors—temperature, salinity, environmental pollution, and food supply—on gametogenesis in sea urchins is discussed.     

Ecophysiological Responses of Larix sibiricaLedeb. and Pinus sibiricaDu Tour Undergrowth to Climate Change

The effects of probable climate change—an increase in atmospheric CO₂(by two times), air temperature, precipitation—on CO₂exchange and temperature dependence of net photosynthesis in the larch and Siberian stone pine undergrowth formed in the light larch forests of West Siberia were studied in chambers with an artificial climate. The change of the aforementioned ecological factors caused an increase in the temperature optima of photosynthesis and the range of optimum temperatures (in the case of Siberian stone pine, to a slightly greater degree). Therefore, the ranges of both species may broaden, and the Siberian stone pine can expand to the north, displacing larch tree stands.     

Composition and Some Ecological Features of Winter Zooplankton in Deep Stratified Lakes

For the first time, zooplankton and environmental factors have been studied in winter in the deep stratified lakes Siverskoe, Borodaevskoe, and Vydogoshch. The zooplankton consists of 18–22 species of rotifers, copepods, and cladocerans, including 15–18 specifically winter, cryophilic and eurythermic forms. The populations of zooplankters reproduce actively: males and egg-bearing females (in copepods), females with embryos and eggs in brood pouches (in cladocerans), and females with attached eggs (in rotifers) are present. In lakes Siverskoe and Borodaevskoe (depth 20–24 m), where oxygen deficiency is observed only in the bottom water layer, the zooplankton populates the greater part of the water column and forms a large aggregation in the oxycline and near the bottom. The abundance of bacteria in these zones is high (up to 4–6 × 10⁶ cells/ml). In Lake Vydogoshch (depth 16 m), oxygen deficiency extends to the middle layers, and all zooplankton is distributed above the oxycline. The biomass of winter zooplankton in Lake Siverskoe in 1983 averaged 1.26 g/m³, with a maximum of 4 g/m³; in 1993, 1.4 and 8.04 g/m²; the respective values in Lake Borodaevskoe were 0.98 and 3.1 in 1983 and 0.14 and 1.6 in 1993; in Lake Vydogoshch, 0.15 and 0.24 in 1983 and 1.25 g/m³ in 1993. The development of winter zooplankton is limited by the size of the zone of oxygen deficiency and depends on the amount of food (bacterioplankton). The distribution of zooplankton in the water column and its biomass in individual layers is determined by the rate of methane formation and oxidation.__________Translated from Ekologiya, No. 3, 2005, pp. 201–214.Original Russian Text Copyright © 2005 by Rivier.     

三峡水库春季浮游植物群落特征及影响因素

浮游植物群落特征是水域生态系统的一个基础信息,三峡水库作为长江经济带环境保护的重要区域,而关于三峡水库全水域浮游植物群落特征及其影响因素的研究报道仍不多见。为了解三峡水库浮游植物群落特征差异及影响因素等一系列基础信息,于2015年4月对三峡水库进行了大范围的调查,调查范围包括17个长江断面(共51个样点)及22条支流库湾(共122个样点)。结果显示:共采集到浮游植物7门39属61种,以绿藻门、硅藻门、甲藻门为主,其中绿藻门有26种,占据总种数的42.62%;硅藻门有16种,占据总种数的26.23%;甲藻门有7种,占据总种数的11.48%。丰度方面,硅藻门占绝对优势,比例为34.26%,其次是隐藻门(23.72%)、蓝藻门(20.96%)。生物量方面,则是甲藻门占绝对优势,其比例达到了44.18%,随后是隐藻门(29.92%)、硅藻门(14.32%)。丰度和生物量分别变化在2.22×10~4～5.12×10~(7 )cells/L和0.001 8～120.99 mg/L之间,且存在一致的趋势,从三峡大坝往长江上游,丰度值和生物量值逐渐增加。支流库湾浮游植物Shannon-Wiener多样性指数显著高于长江干流(Mann-Whitney U检验,P0.001)。冗余分析(Redundancy Analysis,RDA)表明,在长江干流中,水温(WT)、可溶性硅酸盐(DSi)是影响浮游植物群落结构的主要环境因子(P0.001);在支流库湾中,硝态氮(NO~-_3-N)、水温(WT)是影响浮游植物群落结构的主要环境因子(P=0.002)。该研究的成果有助于全面认识了解三峡水库长江干流和支流库湾春季浮游植物种类组成和影响因子,同时对三峡水库水资源管理和水生态保护具有一定参考价值。     

1990~2013年来洞庭湖区鸟类生物多样性热点区时空动态及变动机理

评估与确定生物多样性分布格局与热点区是建立保护区、制定生物保护决策的基础。洞庭湖地区位处长江中游,是我国重要的淡水湖泊湿地生态系统,为中国乃至亚洲较大的鸟类越冬地之一。以洞庭湖地区14种Ⅰ、Ⅱ级重点保护鸟类为指示物种,基于1990~2013年间的多期遥感影像,运用物种生境分布MAXENT模型,选取地形、水系、植被、气候及人类干扰等共35个影响因子,对其进行生境适宜性评价及生物多样性热点区的筛选与制图,并对热点区时空动态特征进行分析。结果表明：（1）鸟类生物多样性热点区的分布范围呈现出组团状特征,1990~2013年来,热点区面积呈下降趋势;（2）鸟类栖息生境景观格局总体上趋于破碎,生境形状向简单且扁平化形态转变,生境格局呈复杂化;（3）经济与社会发展因素对研究区的鸟类生物多样性热点区变化影响显著,而自然因素产生的影响不明显。研究结果在制定区域生物多样性保护规划方案中可体现较好应用价值。     

Patterns of the formation of bird population in the lake-river system of the Asian Subarctic mountains based on the example of the Putorana Plateau

This paper analyzes the patterns of the formation of the aquatic and semiaquatic bird species population under the conditions of the altitudinal zonality of the Putorana Plateau. The population density and abundance of a number of background species was ascertained to decrease from the subalpine belt towards the forest and alpine belt. The bird population density in all the considered aquatic and semiaquatic habitats was revealed to change in a rather narrow range of values: the maximal population density indicator in aquatic and semiaquatic habitats is only 1.9 times higher than the minimal indicator. In the mountainous Subarctic region with a radial macrosymmetry, the spatial dynamics of abundance has a concentrically centrifugal nature in many aquatic and semiaquatic bird species.     

Ecological Analysis of Spleen Hypertrophy in Cyclomorphic Rodents Taking into Account the Type of Ontogeny

The functional approach at the level of physiological functional groups (PFGs) reflecting two types of ontogeny was used to analyze spleen hypertrophy in five species of rodents. In addition to a wide variation of spleen weight, its hypertrophy was observed: in bank voles (Clethrionomys glareolus), the spleen weight was as great as 3.5 g versus the normal value of 100–150 mg. The variation range of the relative spleen weight was estimated. For example, in the dominant species, C. glareolus, this range was considerable (from 2 to 125). A distinct relationship with the types of animal ontogeny was revealed. The genus specificity of the phenomenon—its occurrence in three species of Clethrionomys voles and absence in Microtus voles and mice—was determined in the study region. The animals with normal and hypertrophied spleens did not differ from each other significantly in their vital activity (at least, with respect to the parameters studied). The voles with hypertrophied spleens normally reproduced, and the hypertrophy was asymptomatic. These findings suggest that the populations have adapted to a damaging factor (or factors) in the course of a prolonged coevolution. This parameter is regarded as the indicator of the presence of a damaging factor in the population.     

On the Classification of Aquatic Communities: An Example of Zooplanktonic Cenoses of Karst Lakes in the North of European Russia

Nine lakes in the Arkhangelsk oblast were analyzed with respect to their morphometry, hydrology, and hydrochemistry, and their zooplankton was studied for three years. The data on zooplankton abundance, biomass, the ratio of filter-feeders and predators, the Shannon index of species diversity, and average individual weight of zooplankters were obtained. Differences in the structure of zooplanktonic cenoses were revealed in lakes differing in morphometric parameters, prevailing ions (HCO₃ ^–, SO₄ ^2–), and their concentration.     

Effect of Climatic Changes on the Formation of Siberian Spruce Generations in Subglotsy Tree Stands of the Southern Urals

The correlation between climatic changes and the numbers of trees in the generations of Siberian spruce (Picea obovata Ledeb.) in subgoltsy tree stands of the Southern Urals was analyzed over the past 200 years. The results showed that the most abundant generations appeared in 1809–1816, 1821–1827, 1839–1845, 1850–1867, 1875–1887, 1891–1896, 1900–1904, 1911–1918, 1923–1932, 1944–1952, 1958–1966, and 1975–1995. Their formation proved to be related to the improvement of thermal conditions of the warm season during the five to seven years before and after the emergence of trees and conditions of the cold season in the year of their emergence, as well as to the periods of increased snow depth in late April in the years 27–32 of tree growth.     

Effect of Climatic Changes on Radial Increment and Age Structure Formation in High-Mountain Larch Forests of the Kuznetsk Ala Tau

The relationship between growth indices and renewal rates of the Siberian larch (Larix sibiricaLedeb.) stands that have grown at the timberline in the Kuznetsk Ala Tau mountains during the past 350 years was analyzed. The age generations of larch were formed in the 1640s, 1660s, 1680s, 1700s, 1720s, 1740s, 1760s–1770s, 1800s–1810s, 1850s, 1870s–1880s, 1900s, 1920s, and 1930s–1940s. It was shown that the formation of these age generations coincided with 10- to 30-year periods of increased growth of larch and improved temperature conditions in summer.     

Dynamics of Yielding Capacity of Small Cranberry in Southern Karelia

The dynamics of yielding capacity of small cranberry (Oxycoccus palustris Pers.) were studied in three permanent sampling plots in a natural bog in southern Karelia for 28 years (1975–2002). The yield of berries varied from year to year from 1 to 179 g/m² depending on phytocenotic and, to a greater extent, climatic factors. The proportion between the number of ripe berries and the number of flowers varied from 10 to 66%. No distinct periodicity in the abundance of fruiting was revealed.__________Translated from Ekologiya, No. 4, 2005, pp. 264–268.Original Russian Text Copyright © 2005 by Yudina, Maksimova.     

Effect of water-loving bird colonies on zooplankton in littoral zones of water bodies of different types

Changes in zooplankton developing under the effect of waste products from water-loving bird colonies were studied in water bodies of different types. The trophic status index in the nesting area showed no difference from its background values in an oligomesotrophic water body but was decreased in mesoeutrophic and eutrophic-hypertrophic water bodies. The abundance and biomass of zooplankton in the oligomesotrophic and mesoeutrophic water bodies were consistently higher than background values, while in the eutrophichypertrophic water body they were higher only at the beginning and in the middle of the nesting period. Irrespective of the trophic state of water body, the species diversity of zooplankton in the zone of impact from bird colonies was increased, but the number of dominant species remained unchanged, and no mass development of species indicating high organic load was observed; the proportion of Rotifera in the total abundance and biomass of zooplankton was decreased, that of Copepoda was increased, and the abundance of Cladocera was found to increase with the degree of overgrowing. Among possible explanations, this specific response of zooplankton is most likely due to changes in the ratio of nitrogen and phosphorus in the water.     

Specific features of bird community formation depending on the degree of anthropogenic impact

The population density and relative abundance of some bird species reach the highest values in the communities of habitats with a high degree of anthropogenic transformation. The species diversity of birds shows an inverse correlation with the index of anthropogenic impact (in grades) calculated with regard to a number of parameters. Relevant correlations change periodically, with the correlation coefficient reaching the highest values in the nesting period and decreasing to a minimum during the flight period.     

Comparative Analysis of Foraging Behavior in Aquatic and Semiaquatic Spiders of the Genera Argyroneta,Dolomedes, Pirata,and Pardosa

A group of sympatric aquatic and semiaquatic spiders inhabiting Western Siberia (Argyroneta, Dolomedes, Pirata, and Pardosa) has been studied with respect to specific ethological features. The results provide a basis for the conclusion that these spiders differ in a number of behavioral adaptations related to prey catching and the use of common biotopic space. Experiments with the predator–prey system have shown that spiders have different effects on the abundance of bloodsucking mosquito larvae and on the age and genetic structure (at the chromosomal level) of their populations. The functional role of spiders in communities is discussed.     

Analysis of the long-term dynamics of bird population in forests of the Ilmen State Reserve,Southern Urals

The results of long-term bird censuses in the Ilmen State Reserve are presented. Analysis of dynamic processes in the forest ornithocomplexes has shown that factors influencing changes in the abundance of birds in multispecies communities have unequal effects on different species. It has been found that the abundance dynamics of some species is correlated with spring meteorological parameters and the timing of phenological phases.     

Alternative Types of Ontogeny in Cyclomorphic Rodents and Their Role in Population Dynamics: An Ecological Analysis

Two alternative ontogenetic pathways regularly effected in the populations of small mammals are analyzed as a manifestation of developmental multiversality. The types of ontogeny in rodents are characterized. These data are reflected in the concept of the functional approach. Multiversality of development in plants and animals is considered. Based on the results of long-term (26-year) observations on the natural populations of six rodent species, the dynamics of relationships between the types of ontogeny, abundance, and basic population parameters are analyzed using an example of a background species (Clethrionomys glareolus). A trigger mechanism of switching to a certain type of ontogeny, the role of environmental factors in actuating this mechanism, and the role of the genotype as a basis of multivalence are discussed. The existence of two developmental variants is regarded as a basis for functional rearrangements providing for a high flexibility of population responses and as a mechanism of population regulation determining the dynamics of rodent fauna. An adaptive population response to a board spectrum of influences, including anthropogenic damage, depends not only on the type and strength of the influence, but also on the functional structure of the population. The concepts described in the paper may explain the significance of critical periods in the life of populations.     

Evaluation of the usefulness of bird feathers as a non-destructive biomonitoring tool for organic pollutants: a comparative and meta-analytical approach

In this study, we investigated whether bird feathers can be used as a non-destructive biomonitor for organic pollutants. We analysed the outermost tail feathers of 8 terrestrial and aquatic bird species from Belgium (8 species, n=108) for polychlorinated biphenyls (PCBs), polybrominated diphenyl ethers (PBDEs) and organochlorine pesticides (OCPs). Every compound class could be quantified in one single tail feather of the birds under study (sum PCBs ranging from 5.5 to 510 ng/g feather, sum PBDEs from 0.33 to 53 ng/g feather, sum DDTs from 1.5 to 730 ng/g feather), except for PBDEs in feathers of the common moorhen (Gallinula chloropus). Further, we calculated Pearson correlations between concentrations of organic pollutants in feathers and concentrations in corresponding muscle or liver tissue from the birds. Correlations were found significant in half of the cases of the terrestrial species, but were found not significant for the aquatic species, with the exception of a significant correlation of sum PCBs in the common moorhen. Only for the common buzzard (Buteo buteo) (n=43) all correlations were found significant (0.32相似文献