Soil Microfungi in Two Post-Mining Chronosequences with Different Vegetation Types

Soil microfungi were studied in the Sokolov (Czech Republic) post‐mining dumps afforested with Alnus glutinosa and in the Lusatian (Germany) post‐mining dumps afforested with Pinus sylvestris or P. nigra. Microfungi were isolated using the soil dilution plate method. Soil microfungi communities of two chronosequences were compared by species composition, frequency of species occurrence, and colony forming units of fungi (CFU‐counts). Differences in species occurrence were determined. More species of entomopathogenic microfungi were found from the Sokolov post‐mining area in comparison with the Cottbus post‐mining area. Absidia glauca, A. cylindrospora, Penicillium glabrum, and P. janthinellum were the most frequently isolated species from the Cottbus post‐mining area, while A. glauca, Geomyces pannorum, and Trichoderma koningii predominated at the Sokolov post‐mining area.     

金毛弓背蚁的巢穴结构、头宽频数分布及活动节律

对金毛弓背蚁Camponotus tonkinus Santschi的巢穴结构、工蚁头宽频数特征及巢外活动节律作了系统的观察和分析。发现金毛弓背蚁地下巢穴极为复杂,有纵横交错的通道系统和众多的小室,蚁后室位于巢穴底部,工蚁的头宽为连续性,范围在1.05-3.85mm,频数分布为不对称的单峰,头宽在1.4～2.Omm的个体最多,占总数的72.7%,晴朗天气里工蚁出入巢活动在上午和下午各有一个高峰,中午随温度升高金毛弓背蚁外出活动进入低谷.     

Body size changes among otters, Lutra lutra, in Norway: the possible effects of food availability and global warming

Using museum data of adult specimens whose sex, age, and locality are known, we studied temporal and geographical body size trends among the otter, Lutra lutra, in Norway. We found that body size of the otters increased during the last quarter of the twentieth century, and suggest that this trend is related to increased food availability from fish farming and possibly also to energy saving due to elevated sea temperatures. Birth year and death year explained 38.8 and 43.5%, respectively, of the variation in body size. Body size of otters was positively related to latitude, thus conforming to Bergmann’s rule.     

Body size clines in the European badger and the abundant centre hypothesis

Aim To test the abundant centre hypothesis by analysing the physical and climatic factors that influence body size variation in the European badger (Meles meles). Location Data were compiled from 35 locations across Europe. Methods We used body mass, body length and condylo‐basal length (CBL) as surrogates of size. We also compiled data on latitude, several climatic variables, habitat type and site position relative to the range edge. We collapsed all continuous climatic variables into independent vectors using principal components analysis (PCA), and used a general linear model to explain the morphometric variation in badger populations across the species’ range. Results Body mass and body length were nonlinearly and significantly related to latitude. In contrast, CBL was linearly related to latitude. Body mass changed nonlinearly along the temperature (PC1) gradient, with the highest values observed at mid‐range. Furthermore, body mass, body length and CBL differed significantly among habitats, with badgers showing larger size in temperate habitats and core areas relative to peripheral zones. Main conclusions Our analysis supports the nonlinear pattern predicted by the abundant centre hypothesis only for body mass and body length. These results imply that individuals are largest and heaviest at the centre of the climatic range of badger distribution. Variation of CBL with latitude follows a linear trend, consistent with Bergmann’s rule. Our results provide mixed support for the abundant centre hypothesis, and suggest food availability/quality to be the main mechanism underlying body size clines in this species.     

Multilocus patterns of genetic variation across Cryptosporidium species suggest balancing selection at the gp60 locus

Cryptosporidium is an apicomplexan protozoan that lives in most vertebrates, including humans. Its gp60 gene is functionally involved in its attachment to host cells, and its high level of genetic variation has made it the reference marker for sample typing in epidemiological studies. To understand the origin of such high diversity and to determine the extent to which this classification applies to the rest of the genome, we analysed the patterns of variation at gp60 and nine other nuclear loci in isolates of three Cryptosporidium species. Most loci showed low genetic polymorphism (π_S <1%) and similar levels of between‐species divergence. Contrastingly, gp60 exhibited very different characteristics: (i) it was nearly ten times more variable than the other loci; (ii) it displayed a significant excess of polymorphisms relative to between‐species differences in a maximum‐likelihood Hudson–Kreitman–Aguadé test; (iii) gp60 subtypes turned out to be much older than the species they were found in; and (iv) showed a significant excess of polymorphic variants shared across species from random expectations. These observations suggest that this locus evolves under balancing selection and specifically under negative frequency‐dependent selection (FDS). Interestingly, genetic variation at the other loci clusters very well within the groups of isolates defined by gp60 subtypes, which may provide new tools to understand the genome‐wide patterns of genetic variation of the parasite in the wild. These results suggest that gp60 plays an active and essential role in the life cycle of the parasite and that genetic variation at this locus might be essential for the parasite's long‐term success.     

Mating structure and genetic relatedness among gynes in the primitively eusocial wasp Polistes snelleni (Hymenoptera: Vespidae)

Mating structure and genetic relatedness among gynes (potential reproductive females) of the paper wasp Polistes snelleni were investigated using DNA microsatellite markers. All colonies had one foundress inseminated by a single male, and no sign of inbreeding was detected. The mean genetic relatedness among gynes was 0.734 ± 0.028 (SE), which is not significantly different from the expected value of 0.75 for full sisters.     

Diet overlap among two Asian carp and three native fishes in backwater lakes on the Illinois and Mississippi rivers

Bighead and silver carp are well established in the Mississippi River basin following their accidental introduction in the 1980s. Referred to collectively as Asian carp, these species are filter feeders consuming phytoplankton and zooplankton. We examined diet overlap and electivity of Asian carp and three native filter feeding fishes, bigmouth buffalo, gizzard shad, and paddlefish, in backwater lakes of the Illinois and Mississippi rivers. Rotifers, Keratella spp., Brachionus spp., and Trichocerca spp., were the most common prey items consumed by Asian carp and gizzard shad, whereas crustacean zooplankton were the preferred prey of paddlefish. Bigmouth buffalo diet was broad, including both rotifers and crustacean zooplankton. Dietary overlap with Asian carp was greatest for gizzard shad followed by bigmouth buffalo, but we found little diet overlap for paddlefish. Diet similarity based on taxonomy correlated strongly with diet similarity based on size suggesting filtration efficiency influenced the overlap patterns we observed. Although rotifers were the most common prey item consumed by both bighead and silver carp, we found a negative relation between silver carp CPUE and cladoceran density. The competitive effect of Asian carp on native fishes may be forestalled because of the high productivity of Illinois and Mississippi river habitats, yet the potential for negative consequences of Asian carp in less productive ecosystems, including Lake Michigan, should not be underestimated.     

Comparison of dwarf bamboos (Indocalamus sp.) leaf parameters to determine relationship between spatial density of plants and total leaf area per plant

The relationship between spatial density and size of plants is an important topic in plant ecology. The self‐thinning rule suggests a ?3/2 power between average biomass and density or a ?1/2 power between stand yield and density. However, the self‐thinning rule based on total leaf area per plant and density of plants has been neglected presumably because of the lack of a method that can accurately estimate the total leaf area per plant. We aimed to find the relationship between spatial density of plants and total leaf area per plant. We also attempted to provide a novel model for accurately describing the leaf shape of bamboos. We proposed a simplified Gielis equation with only two parameters to describe the leaf shape of bamboos one model parameter represented the overall ratio of leaf width to leaf length. Using this method, we compared some leaf parameters (leaf shape, number of leaves per plant, ratio of total leaf weight to aboveground weight per plant, and total leaf area per plant) of four bamboo species of genus Indocalamus Nakai (I. pedalis (Keng) P.C. Keng, I. pumilus Q.H. Dai and C.F. Keng, I. barbatus McClure, and I. victorialis P.C. Keng). We also explored the possible correlation between spatial density and total leaf area per plant using log‐linear regression. We found that the simplified Gielis equation fit the leaf shape of four bamboo species very well. Although all these four species belonged to the same genus, there were still significant differences in leaf shape. Significant differences also existed in leaf area per plant, ratio of leaf weight to aboveground weight per plant, and leaf length. In addition, we found that the total leaf area per plant decreased with increased spatial density. Therefore, we directly demonstrated the self‐thinning rule to improve light interception.     

Scaling up evolutionary responses to elevated CO2: lessons from Arabidopsis

Results from norm of reaction studies and selection experiments indicate that elevated CO₂ will act as a selective agent on natural plant populations, especially for C₃ species that are most sensitive to changes in atmospheric CO₂ concentration. Evolutionary responses to CO₂ may alter plant physiology, development rate, growth, and reproduction in ways that cannot be predicted from single generation studies. Moreover, ecological and evolutionary changes in plant communities will have a range of consequences at higher spatial scales and may cause substantial deviations from ecosystem level predictions based on short‐term responses to elevated CO₂. Therefore, steps need to be taken to identify the plant traits that are most likely to evolve at elevated CO₂, and to understand how these changes may affect net primary productivity within ecosystems. These processes may range in scale from molecular and physiological changes that occur among genotypes at the individual and population levels, to changes in community‐ and ecosystem‐level productivity that result from the integrative effects of different plant species evolving simultaneously. In this review, we (1) synthesize recent studies investigating the role of atmospheric CO₂ as a selective agent on plants, (2) discuss possible control points during plant development that may change in response to selection at elevated CO₂ with an emphasis at the primary molecular level, and (3) provide a quantitative framework for scaling the evolutionary effects of CO₂ on plants in order to determine changes in community and ecosystem productivity. Furthermore, this review points out that studies integrating the effects of plant evolution in response to elevated CO₂ are lacking, and therefore more attention needs be devoted to this issue among the global change research community.