State of Birch Outliers in the Southern Trans-Urals in the Zone of High Anthropogenic Load on Natural Ecosystems

Biology Bulletin - Abstract—The results of our study of the ecosystem diversity and state of forest outliers located in the Shchuchanskii district of the Kurgan region are presented. The...     

The Concept of Dispositional Regulation of Individual Social Behavior

After a period of relative neglect by psychologists of issues of social motivation and goal-directed behavior (in favor of attending to the person as a "cognizer," or reinforcement-shaped "responder"), it is clear that the preoccupations of Miller, Galanter, & Pribram (1960) a quarter-century ago have been taken up with renewed interest. Current investigators are of many different persuasions—e.g., cognitively oriented theorists concerned with "lay epistemology" (Kruglanski & Klar, 1986), "personologists" interested in person-environment interactions (Little, 1983), psychologists attempting to clarify the structure and components of action (e.g., Brenner, 1980), etc. Readers familiar with the work of Leont'ev (1975) and the translations and discussions of related work (Wertsch, 1979) will know that a concern with goal direction has never been absent from psychology in the USSR.     

Consortia in Aquatic Ecosystems of the Transbaikalia

A survey in the basin of the Khilok River (a right tributary of the Selenga River) in 1999–2002 allowed us to reveal and describe the consortia of cyanobacteria Stratonostoc linckia f. linckia and Stratonostoc verrucosum, green alga Cladophora aegagropila, stonewort Nitella opaca, water moss Fontinalis sp., and duckweed Lemna trisulca. The relationship between the consort organisms and edificator plants can become the limiting factor in these communities. The long-term studies of the benthic communities of the Arakhlei Lake demonstrate the significance of the consortium approach in the long-term prediction of changes in the lake ecosystem.     

The Relation Between Adenosine Triphosphate and Microbial Biomass in Diverse Aquatic Ecosystems

By using autoradiographic examination of ¹⁴C labeled viable cells, natural phytoplankton communities were separated into living and non-living components. Comparisons of carbon to adenosine triphosphate (ATP) content of living cells yielded consistent ratios with depth, during periods of high and low nutrient supply at Lake Tahoe. Over time the ratio fluctuated by no more than ± 17% of the mean between the time of maximum nutrient supplies and nutrient depletion. The viability of specific phytoplankton groups was surprisingly low at times, indicating that conventional counting methods tend to overestimate live biomass. A survey of lakes differing in trophic states and having diverse phytoplankton and bacterial assemblages has shown that ATP measurements can be used as an accurate measure of total living microbial biomass.     

Experimental Approach to the Role of Protozoa in Aquatic Ecosystems

In enrichment batch experiments, samples from three water bodieswere alternatively supplemented by various amounts of organicmaterial and incubated at 20 C. Colpidium campylum reached itshighest total cell volumes in cultures with the highest initialtotal cell volumes in cultures with the highest initial concentrationsof organics; Cyclidium glaucoma preferred lower concentrations;and Glaucoma chattoni occupied the intermediate position. Noneof the species preferred any special type of organic material.In two-stage continuous-flow units, a mixed culture of bacteriawas kept in stage I and the clones of ciliates were maintainedin stage II. The interrelations between the total cell volumesof ciliates at various concentrations of bactopeptone were inaccordance with the results from the enrichment experiments.Since the growth of bacteria continued in the presence of ciliates,a four-stage apparatus was constructed in which a bacterialculture was raised and diluted in three stages before enteringthe culture ofColpidium. The bacterial growth in the presenceof Colpidium was not eliminated even by this arrangement, asdemonstrated by dosing antibiotics along with bacteria. An effectof ciliate metabolites on bacterial growth rate is suggested,completing a metabolic cycle in the bacteria-protozoa system.     

Anthropogenic Effects of Reservoir Construction on the Parasite Fauna of Aquatic Wildlife

The creation of large freshwater reservoirs is one of the most dramatic anthropogenic impacts on the natural environment. With worldwide rising demand for water, the construction of more reservoirs is inevitable. Although the effects of reservoir construction on many medically important parasites are well known and appreciated, changes to aquatic wildlife host–parasite interactions have been largely undervalued even though a large body of literature exists. The present review examines changes in the wildlife parasite fauna during the impoundment of reservoirs, focusing on the parasites of invertebrates, fish, and birds, the effects both upstream and downstream of the reservoir, parasitic zoonoses, the associated pollution generated, and assesses the impact of the recently completed Three Gorges Dam in China on the Yangtze River’s parasite fauna.     

General Model of Microbial Growth and Decomposition in Aquatic Ecosystems

A model capable of simulating freely suspended and attached decomposers, particulate organic matter, labile and refractory dissolved organic matter, inorganic nitrogen, and phosphate in the open-water portion of lakes is presented. Examples are given showing the utility of the model when coupled to the whole-ecosystem model CLEANER.     

The Influence of Soil Biodiversity on Hydrological Pathways and the Transfer of Materials between Terrestrial and Aquatic Ecosystems

The boundaries between terrestrial and aquatic ecosystems, known as critical transition zones (CTZ), are dynamic interfaces for fluxes of water, sediment, solutes, and gases. Moreover, they often support unique or diverse biotas. Soils, especially those of riparian zones, have not been recognized as CTZ even though they play a critical role in regulating the hydrologic pathways of infiltration and leaching, or runoff and erosion, which can cumulatively affect biogeochemical processes and human livelihoods at landscape scales. In this review, we show how the processes that regulate hydrologic fluxes across and through soil CTZ are influenced by the activities of soil biota. Our message is fourfold. First, there are a variety of ways in which soil biodiversity, in terms of richness and dominance, can influence hydrological pathways in soil and thus the transfer of materials from terrestrial to aquatic ecosystems. Second, the influence of soil organisms on these hydrological pathways is very much interlinked with other environmental, soil biophysical, and vegetation factors that operate at different spatial and temporal scales. Third, we propose that the influence of soil biodiversity on hydrological pathways is most apparent (or identifiable), relative to other factors, in situations that lead to the dominance of certain organisms, such as larger fauna. Fourth, soils are buffered against environmental change by biophysical properties that have developed over long periods of time. Therefore, the effects of changes in soil biodiversity on hydrological processes at the ecosystem scale might be delayed and become most apparent in the long term. Received 25 February 2000; accepted 11 December 2000.     

Concept and Classification of Coarse Woody Debris in Forest Ecosystems

Coarse woody debris (CWD) is generally considered as dead woody materials in various stages of decomposition, including sound and rotting logs, snags, and large branches. CWD is an important functional and structural component of forested ecosystems and plays an important role in nutrient cycling, long-term carbon storage, tree regeneration, and maintenance of heterogeneous environmental and biological diversity. However, the definition and classification of CWD have been the subject of a long debate in forest ecology. CWD has not been precisely defined. Recently, with the rapid development of landscape ecology in CWD, the USDA Forest Service and the Long Term Ecological Research (LTER) have provided a standardized definition and classification for CWD, which makes data comparison in landscape scale possible. Important characteristics of their definition include: (1) a minimum diameter (or an equivalent cross-section) of CWD ≥10 cm at the widest point (the woody debris with a diameter from 1 to 10 cm should be defined as fine woody debris, and the rest is litterfall); and (2) sound and rotting logs, snags, stumps, and large branches (located above the soil), and coarse root debris (larger than 1 cm in diameter). This classification has greatly facilitated CWD studies. Therefore, it has been widely applied in some countries (particularly in North America). However, this classification has long been a source of confusion for forest ecologists in China. Furthermore, different definitions and criteria are still adopted in individual studies, which makes the interpretation and generalization of their work difficult. This article reviewed recent progress in classifying CWD, with an emphasis on introducing the classification system of the USDA Forest Service and the LTER. It is expected that this review will help facilitate the development of standardized definition and classification suitable to forest ecosystems in China. Translated from Acta Ecologica Sinica, 2005, 25(1) (in Chinese)     

Environmental Controls of Cryptogam Composition and Diversity in Anthropogenic and Natural Peatland Ecosystems of Chilean Patagonia

Peatlands exhibit highly characteristic ecological traits and are unique complex ecosystems. Nevertheless, knowledge about southern South American peatlands is very limited. In this study, we analyzed species composition of bryophytes and lichens of Southern Hemisphere peatlands, specifically from eight peatlands of Isla Grande de Chiloé (Chiloé Island) in southern Chile (42°–43°S and 75°–73°W). Two kinds of Sphagnum peatlands were studied: natural and anthropogenic peatlands. Our results indicate the existence of clear environmental gradients affecting the structure of bryo-lichenic communities in the Sphagnum peatlands of Chiloé. Canonical correspondence analysis suggests that variation in bryophyte and lichen species composition mainly follows ombrotrophic–minerotrophic and lithotrophic-thalassotrophic gradients. Surface-water chemistry is the most significant factor accounting for changes in floristic composition among our study sites. In contrast to our expectations, bog origin (natural or anthropic) was not the most significant factor accounting for changes in floristic composition among peatlands. Other elements, such as the water source supplying peatlands or the influence of sea spray, were more relevant in the bryo-lichenic flora species occurrence in the peatlands of Chiloé. We also observed clear differences in ecological niches among species in general additive model response curves. Therefore, our results show that despite the origin, the ecology of peatlands follows common rules with peatlands from the Northern Hemisphere.     

Changes in Rodent Populations in Eastern Fennoscandia under the Influence of Anthropogenic Transformations of Boreal Ecosystems

Long-term (1966–2015) stationary and expedition studies in eastern Fennoscandia have revealed specific changes in the structure and abundance of rodent populations under the influence of concentrated forest fells. The general patterns of the influence of intensive forest exploitation on the natural habitats, numbers, territorial distribution, and ecological features of small rodents in the region are analyzed. It has been established that, for most rodent species, industrial harvesting leads to a decrease in the total abundance of populations, as well as to an erratic shift in population dynamics with sudden short recoveries and deep longterm depressions, the formation of a nonresistant mosaic spatial distribution, and a disturbance of the rates and a decrease in the intensity of breeding and population reproduction.     

Concept and Classification of Coarse Woody Debris in Forest Ecosystems

Coarse woody debris (CWD) is generally considered as dead woody materials in various stages of decomposition,including sound and rotting logs,snags,and large branches.CWD is an important functional and structural component of forested ecosystems and plays an important role in nutrient cycling,long-term carbon storage,tree regeneration,and maintenance of heterogeneous environmental and biological diversity.However,the definition and classification of CWD have been the subject of a long debate in forest ecology.CWD has not been precisely defined.Recently,with the rapid development of landscape ecology in CWD,the USDA Forest Service and the Long Term Ecological Research (LTER)have provided a standardized definition and classification for CWD,which makes data comparison in landscape scale possible.Important characteristics of their definition include:(1) a minimum diameter (or an equivalent crosssection) of CWD≥10 cm at the widest point (the woody debris with a diameter from 1 to 10 cm should be defined as fine woody debris,and the rest is litterfall);and (2) sound and rotting logs,snags,stumps,and large branches (located above the soil),and coarse root debris (larger than 1 cm in diameter).This classification has greatly facilitated CWD studies.Therefore,it has been widely applied in some countries (particularly in North America).However,this classification has long been a source of confusion for forest ecologists in China.Furthermore,different definitions and criteria are still adopted in individual studies,which makes the interpretation and generalization of their work difficult.This article reviewed recent progress in classifying CWD,with an emphasis on introducing the classification system of the USDA Forest Service and the LTER.It is expected that this review will help facilitate the development of standardized definition and classification suitable to forest ecosystems in China.     

Using Parasitic Load to Measure the Effect of Anthropogenic Disturbance on Vervet Monkeys

Vervet monkeys, Chlorocebus pygerythrus, thrive in urban areas of KwaZulu-Natal, South Africa, and present a suitable model to assess parasitic load as a measure of anthropogenic disturbance, such as urbanization. We collected vervet monkey faecal samples from four study sites representing a gradient of land use and urbanization. We assessed faecal parasites using the faecal flotation method calculating eggs per gram and parasite richness. Overall, the more urban vervet monkey populations had a significantly higher parasite richness and abundance. Our study shows the applicability of using parasite load to measure the effect of urbanization on wildlife.     

Comparative Toxicity of Three Organic Acids to Freshwater Organisms and Their Impact on Aquatic Ecosystems

The comparative toxicity of lactic acid, acetic acid, and benzoic acid to tilapia (Oreochromis mossambicus), cladoceran crustacea (Moina micrura), and oligochaete worm (Branchiura sowerbyi) were determined using static bioassay tests. Worms were found most sensitive to all the acids whereas the cladoceran was found most resistant to lactic acid and the fish most resistant to acetic acid and benzoic acid. The 96h LC₅₀ values of lactic acid, acetic acid, and benzoic acid, were, respectively, 257.73, 272.87, and 276.74 mg L^?1 for O. mossambicus; 329.12, 163.72, and 71.65 mg L^?1 for M. micrura and 50.82, 14.90, and 39.47 mg L^?1 for B. sowerbyi. Tilapia lost appetite at sub-lethal concentrations as low as 2.18 mg L^?1 lactic acid, 1.26 mg L^?1 acetic acid, and 13.84 mg L^{? 1} of benzoic acid. Growth and reproduction of the fish were affected following 90-day chronic exposure to sub-lethal concentrations of the acids. Minimum effective concentration of the acids that significantly reduced food conversion efficiency (FCE), percent increase of weight, specific growth rate, yield and fecundity of the fish were 2.18, 1.47, and 3.95 mg · L^?1 of lactic acid, acetic acid, and benzoic acid, respectively. Effects of acetic acid and benzoic acid on FCE, weight increase, and yield were not significantly different from each other whereas lactic acid produced different effects from acetic acid as well as benzoic acid. Mean values of dissolved oxygen, primary productivity, and plankton populations of the test medium significantly reduced from control at 16.94 mg L^?1 lactic acid, 16.79 mg L^?1 acetic acid, and 13.84 mg L^?1 benzoic acid.     

Bioturbation as Driver of Zooplankton Recruitment,Biodiversity and Community Composition in Aquatic Ecosystems

In an experimental study we assessed if benthic bioturbating invertebrates affect the recruitment (hatching) of zooplankton from the sediment, and if this effect persists as differences in the zooplankton community in the water column, that is, if bioturbation quantitatively stimulates benthic–pelagic coupling. We investigated the effects of four different benthic invertebrates (Asellus aquaticus, Chironomus plumosus, Tubifex tubifex in the presence or absence of the predator Sialis lutaria). In total, 45 zooplankton taxa hatched from the sediment and the hatching success of some of these was dependent on the species identity of the bioturbating invertebrate. The predator Sialis reduced the abundance of all three invertebrate species, but tended to positively influence the zooplankton recruitment rates, possibly through increasing the activity of the bioturbating invertebrates. The most striking effect of bioturbation on the hatching and pelagic zooplankton community properties was that, on average, 11% more species hatched in the Asellus treatment than in any other treatment. This was also mirrored in the zooplankton water column community where, on average, 7% more species established a viable population in treatments with Asellus as bioturbator. In a complementary field survey, Asellus was more common in littoral than in profundal sediments. Because Asellus strongly affected recruitment of zooplankton in our experiment, we argue that bioturbation may partly explain why recruitment of resting stages of both phyto- and zooplankton is generally higher in littoral than in profundal areas.     

运用概念图进行“植物的激素调节”的教学内容分析

教师在备课的过程中,对教学内容进行系统的分析和梳理是一个非常重要的环节.它是教师划分教学内容、确定教学思路、分配教学时间、设计教学活动以及选择教学策略的直接依据.而概念图恰恰可以有效地帮助教师对教学内容进行系统的分析和梳理.以高中生物学课"植物的激素调节"为例,介绍了利用概念图进行教学内容分析的一般步骤友详细过程.     

Pico- and Nanoplankton in Aquatic Ecosystems in the Valley of the Lakes and Great Lakes Depression (Mongolia)

The abundance and biomass of bacterioplankton, phototrophic picoplankton, and heterotrophic nanoflagellates has been determined in lakes, rivers, and reservoirs located in the Valley of the Lakes and Great Lakes Depression (Mongolia). The species richness of the heterotrophic flagellates and their consumption of bacteria are estimated. Pico- and nanoplankton are the most abundant in shallow mineral lakes Orog and Tatsyn and in the freshwater Durgun Reservoir. Heterotrophic nanoflagellates consume 26–92% (on average 66%) of the daily bacterioplankton production. Thus, flagellates are important in the transfer of bacterial carbon to the higher levels of planktonic trophic webs. A total of 30 species and their forms of heterotrophic flagellates from 14 large taxa are identified. The highest species diversity of these protists are found in the Durgun and Taishyr reservoirs.