Multiple differentiation centres of a non-Mediterranean butterfly species in south-eastern Europe

Aim  The analysis of the phylogeographical structures of many European species reveals the importance of Mediterranean glacial refugia for many thermophilic species, but also underlines the relevance of extra-Mediterranean glacial differentiation centres for a number of temperate species. In this context, phylogeographical analyses of species from south-eastern Europe are highly important for a comprehensive understanding of Europe as a whole.
Location  Romania and Bulgaria.
Methods  We analysed 19 allozyme loci for 615 individuals of the temperate butterfly species Erebia medusa from 28 populations.
Results  These populations had an intermediate genetic diversity, but the Bulgarian populations were significantly more diverse than the ones north of the Danube in Romania. The differentiation among populations was strong, and 52.1% of the genetic variance among populations was distributed between these two countries. The genetic differentiation was considerably stronger in Romania than in Bulgaria, but several sublineages were distinguished within each of these countries.
Main conclusions  The observed genetic structure is so strong that it is most probably the result of glacial differentiation processes in south-eastern Europe and not a post-glacial structure. The strong differentiation into the two groups north and south of the Danube suggests a separating effect by this river valley. The strong differentiation accompanied with genetic impoverishment in Romania suggests the existence of several differentiation centres: at least two small ones on the southern slopes of the southern Carpathians and one in the eastern Carpathian Basin. The considerably weaker differentiation among the Bulgarian samples and their significantly higher genetic diversity imply that gene flow occurred among different regions of Bulgaria during the last ice age.     

Structure and diversity of stream invertebrate assemblages: the influence of temperature with altitude and latitude

1. Structure and diversity of the macroinvertebrate fauna were studied in relation to altitude and latitude among three groups of streams from Ecuador (lowland: 100–600 m, Central Valley: 2600–3100 m, páramo: 3500–4000 m), and one group from the temperate lowland region of Denmark. The streams in the four regions were comparable with regard to physical characteristics such as size, current and substratum.
2. In terms of faunal composition the Ecuadorian highland streams bore more resemblance to the Danish lowland streams than the Ecuadorian lowland streams. The greater similarity between the Ecuadorian highland and the Danish streams, however, was due to the large number of insect families in the Ecuadorian lowlands, many of which were not found in the other regions. Of ten physico-chemical parameters measured, maximum stream temperature explained by far the most variability in faunal composition.
3. The number of insect orders and families increased linearly with maximum stream temperature and therefore decreased with altitude and latitude. A compilation of literature data on insect richness and maximum water temperature from streams around the world confirmed this pattern, yielding a common linear relation for both temperate and tropical streams. This pattern may arise due to a direct temperature effect on speciation but is probably also related to geological history and the influence of climatic changes on stream ecosystems. We estimate that small, tropical, lowland streams have, on average, a two- to fourfold higher species richness than temperate lowland streams.     

Changing dynamics of the pine beauty moth (Panolis flammea) in Britain: the loss of enemy free space?

1 The pine beauty moth Panolis flammea has two main host plants in Britain: Pinus sylvestris (Scots pine), which is the ancestral food plant where the insect is never abundant enough to cause tree mortality, and Pinus contorta (lodgepole pine), an introduced host tree that has experienced periodic widespread tree mortality due to this pest.
2 We review the recent literature, published mostly after the year 2000, regarding the impact of natural enemies on the population dynamics of P. flammea in Britain.
3 The natural enemies of P. flammea are more diverse and abundant in Scots pine habitat than in lodgepole pine habitat and some of them show differential selection for P. flammea larvae in Scots pine habitat over those located in lodgepole pine habitat.
4 It is concluded that the difference in the population dynamics of this insect in the two different habitats was probably the result of the P. flammea finding enemy-free space in lodgepole pine habitat.
5 Recent evidence on the diversity and impact of natural enemies on lodgepole pine has demonstrated that they currently have a much more significant impact on this pest than they did in the 1970s and 1980s, when outbreaks were frequent.     

中国中亚热带东部常绿阔叶林主要类型的群落多样性特征

 本文通过10个地区61个样地资料分析,研究了中亚热带东部常绿阔叶林群落多样性特征及其随纬度、海拔梯度的变化。结果表明,中亚热带东部常绿阔叶林群落丰富度为49±17种(样地面积400m2),各层次的多样性表现为灌木层(包括幼树与幼苗)>乔木层>草本层。常绿阔叶林各类型间的差异远比落叶阔叶林与多样性较低的常绿阔叶林之间的差异大。各层次中变化幅度从大到小的顺序为：草本层>乔木层>灌木层。在所研究地区常绿阔叶林的群落多样性没有表现出明显的随纬度梯度和海拔梯度的变化规律。     

Species compositions and ecology of the riverine ichthyofaunas in two Sulawesian islands in the biodiversity hotspot of Wallacea

This account of the riverine ichthyofaunas from the islands of Buton and Kabaena, off south‐eastern mainland Sulawesi, represents the first detailed quantitative checklist and ecological study of the riverine fish faunas in the biological hotspot of Wallacea. The results are based on analysis of samples collected by electrofishing at a wide range of sites from July to September in both 2001 and 2002. While the fauna was diverse, with the 2179 fishes caught comprising 64 species representing 43 genera and 22 families, the catches were dominated by the Gobiidae (26 species and 25% by numbers), Eleotridae (seven species and 27% by numbers), Zenarchopteridae (three species and 22% by numbers) and Anguillidae (two species and 12% by numbers). The most abundant species were the eleotrids Eleotris aff. fusca‐melanosoma and Ophieleotris aff. aporos, the anguillid Anguilla celebesensis, the zenarchopterids Nomorhamphus sp. and Nomorhamphus ebrardtii and the gobiids Sicyopterus sp. and Glossogobius aff. celebius‐kokius. The introduced catfish Clarias batrachus was moderately abundant at a few sites. Cluster analysis, allied with the similarity profiles routine SIMPROF, identified seven discrete groups, which represented samples from sites entirely or predominantly in either Buton (five clusters) or Kabaena (two clusters). Species composition was related to geographical location, distance from river mouth, per cent contribution of sand and silt, altitude and water temperature. The samples from the two islands contained only one species definitively endemic to Sulawesi, i.e. N. ebrardtii and another presumably so, i.e. Nomorhamphus sp., contrasting starkly with the 57 species that are endemic to Sulawesi and, most notably, its large central and deep lake systems on the mainland. This accounts for the ichthyofaunas of these two islands, as well as those of rivers in northern mainland Sulawesi and Flores, being more similar to each other than to those of the central mainland lake systems. This implies that the major adaptive radiation of freshwater fishes in Sulawesi occurred in those lacustrine environments rather than in rivers.     

Soil nitrogen and carbon heterogeneity in woodlands and grasslands: contrasts between temperate and tropical regions

Aim  Soil resource heterogeneity is linked to several ecological processes including invasion of woody species into grasslands. Studies from the temperate zone have demonstrated greater soil heterogeneity beneath woody vegetation than beneath grasslands. Woody species have a more widespread and coarser root system than herbaceous species, and may have a competitive advantage in relatively heterogeneous soils. We tested the global generality of greater soil heterogeneity beneath woody vegetation.
Location  Global.
Methods  We used data from published literature for soil nitrogen and carbon heterogeneity from paired woodland and grassland sites around the world.
Results  Woodland and grassland soil heterogeneities from paired observations were strongly correlated. There was, however, significant geographical variability in the relationship. Soils were more heterogeneous in woodlands than grasslands in temperate areas, but the opposite was true for tropical habitats. Grassland soils were more heterogeneous at lower than higher latitudes. Woodland soil heterogeneity did not vary with latitude.
Main conclusions  The previously described high soil heterogeneity in woody vegetation compared to grasslands holds only for temperate regions. Consequently, the relationship between soil resource heterogeneity and vegetation type is dependent on the study region. Macroecological studies should test the generality of relationships between soil and vegetation at the global scale.     

甘肃鸡类物种多样性研究

甘肃鸡类有19种,随纬度变化形成了物种多样性梯度。本文通过气候(年无霜天数、元月均温、年均温、7月均温和年降水量),海拔高差,纬度和植被类型多样性与各县鸡类多样性相关统计分析,揭示了7月均温,年均降水量,海拔高差和纬度是控制甘肃鸡类多样性的主要因素,而甘肃鸡类多样性与植被类型多样性无关。在降水量400—650mm和海拔高差1500—3500m的地带种类最多。一个地区物种的多少不仅取决于其离物种库的远近,还取决于这一地区环境空间异质性程度。     

Ancient lakes as hotspots of diversity: a morphological review of an endemic species flock of <Emphasis Type="Italic">Tylomelania</Emphasis> (Gastropoda: Cerithioidea: Pachychilidae) in the Malili lake system on Sulawesi,Indonesia

The viviparous freshwater gastropod Tylomelania (Caenogastropoda: Cerithioidea: Pachychilidae) endemic to the Indonesian island Sulawesi has radiated extensively in two ancient lake systems. We here present the first systematic species-level review of taxa in the five lakes of the Malili lake system, which contains the most diverse and best studied freshwater fauna on Sulawesi. Our results indicate a significantly higher diversity of Tylomelania in these lakes than previously perceived based on morphological evidence for delimiting the taxa. We describe nine new species, thus increasing the number of taxa known from the Malili lakes to 25. Tylomelania species are inhabiting all available substrates in the lakes, and the diversity of habitats is reflected in an unparalleled range of radula types in this closely related group. Several species show a high intraspecific variability in some characters, and their closer investigation will probably lead to the discovery of more cryptic species. As it is, this species flock on Sulawesi is among the largest freshwater mollusc radiations known. Since the Malili lake system also contains other large endemic species flocks of e.g. crustaceans and fishes, it is a major hotspot of freshwater biodiversity in Asia to become a conservation priority. Handling editor: K. Martens     

Insect herbivore guilds and species—area relationships: leafminers on British trees

Abstract. 1. 239 species of leafmining insects have been recorded from thirty-seven species of trees and large shrubs in Britain.
2. A significant species—area relationship was obtained for these insects, but it explained only 19% of the variation about the regression he. A further 23% of the variation may be accounted for by taxonomic relationship of host plants.
3. A significant correlation was established between the number of species of leafminers and those of mesophyll-feeding leafhoppers for twentyeight host tree species. Both guilds are dominated by host specific feeders.
4. It is suggested that species—area effects are important in determining species richness of phytophagous insects mainly when groups of closely related host plants are considered. With more diverse arrays of hosts, taxonomic influences, which are probably mainly chemical, may outweigh such area related effects.     

Host introductions and the geography of parasite taxonomic diversity

Aim Geographical variation in parasite diversity is examined among populations of fish in their original heartland and in areas where they have been introduced. The diversity in heartland and introduced populations is contrasted, and also compared with the expectations of a null model. Location Data on the parasite communities of two salmonid fish species were obtained: the rainbow trout Oncorhynchus mykiss in its British Columbia heartland and in introduced populations in North America, Great Britain, South America and New Zealand; and the brown trout Salmo trutta in heartland populations from Great Britain, and in introduced populations in North America, South America and New Zealand. Methods The average taxonomic distinctness and its variance were computed for each parasite community, and used as measures of the taxonomic diversity of parasite species in each fish population. Observed values of taxonomic distinctness were also compared with those expected if each community was a random selection from the world list of parasite species known for each of the two host species. Results Few parasite communities departed from the expectations of the null model, i.e. few had a taxonomic diversity of parasites greater or lower than that expected from a random selection of parasite species. However, these departures were not more or less likely among heartland fish populations than among introduced ones. In both fish species, parasite communities in introduced populations tended to be a little more taxonomically diverse than in the heartland populations. Main conclusions Overall, the results suggest that the accumulation of parasite species in introduced hosts over short (ecological) periods of time can result in parasite assemblages that are just as, or even more, taxonomically diverse than those developed over much longer (evolutionary) time frames in the host species geographical heartland. This finding highlights the importance of ecological factors in parasite biodiversity in addition to coevolutionary processes.     

Living on the edge: British and Irish woodland birds in a European context

This paper reviews broad geographical patterns in the species composition of breeding woodland bird communities from Ireland to eastern Europe and outlines how processes affecting woodland birds in Britain and Ireland may differ from those operating in mainland Europe. Bird communities in British and Irish woodlands consist of a subset of the species occurring within European forests at similar latitudes. The occurrence of virtually all groups of forest birds is lower in Britain, and strikingly lower in Ireland, than in other temperate areas of mainland Europe. This phenomenon appears to form part of a west–east gradient in species diversity and is probably not just a consequence of insularity. Across this gradient there appears to be broad geographical constancy in the types (taxonomic, ecological and life-history groups) of species present. There is considerable spatial variation in habitat use by forest species within Europe. Some species in Britain probably use habitats in different ways to elsewhere for reasons related to competition, predation and historical adaptation to landscape change. Several species appear to reach the limits of their geographical ranges within Britain (i.e. in the absence of physical barriers). We suggest that range contraction of one of these species, the Common Nightingale Luscinia megarhynchos , in Britain may partially reflect redistribution into the highest quality areas in response to a wider population decline. It is argued that conclusions drawn from studies of forest birds in Britain do not necessarily apply in other regions and vice versa. There is a need for large-scale studies in Europe of the spatial variation in organization of forest bird assemblages, habitat use and the genetic structure of populations.     

Natural vegetation cover in the landscape and edge effects: differential responses of insect orders in a fragmented forest

Human activities have led to global simplification of ecosystems, among which Neotropical dry forests are some of the most threatened. Habitat loss as well as edge effects may affect insect communities. Here, we analyzed insects sampled with pan traps in 9 landscapes (at 5 scales, in 100–500 m diameter circles) comprising cultivated fields and Chaco Serrano forests, at overall community and taxonomic order level. In total 7043 specimens and 456 species of hexapods were captured, with abundance and richness being directly related to forest cover at 500 m and higher at edges in comparison with forest interior. Community composition also varied with forest cover and edge/interior location. Different responses were detected among the 8 dominant orders. Collembola, Hemiptera, and Orthoptera richness and/or abundance were positively related to forest cover at the larger scale, while Thysanoptera abundance increased with forest cover only at the edge. Hymenoptera abundance and richness were negatively related to forest cover at 100 m. Coleoptera, Diptera, and Hymenoptera were more diverse and abundant at the forest edge. The generally negative influence of forest loss on insect communities could have functional consequences for both natural and cultivated systems, and highlights the relevance of forest conservation. Higher diversity at the edges could result from the simultaneous presence of forest and matrix species, although “resource mapping” might be involved for orders that were richer and more abundant at edges. Adjacent crops could benefit from forest proximity since natural enemies and pollinators are well represented in the orders showing positive edge effects.     

A test of two hypotheses explaining the seasonality of reproduction in temperate mammals

1. Two proposed hypotheses about energy allocation were tested to explain the patterns of seasonal reproduction found in temperate mammals. The two hypotheses predict either that total demand for energy is greater during reproduction than during winter (when thermoregulatory costs are high) (Increased Demand Hypothesis) or that total costs during winter are greater than or equal to total costs during reproduction (Reallocation Hypothesis).
2. Data were compiled from the literature on summer (non-reproducing) and winter metabolic rates of temperate mammals, and were used on litter sizes and a published equation to predict metabolic rates during lactation.
3. All three measures of metabolic rate scaled to body mass with slopes significantly less than one. Metabolic rates during winter averaged ≈ 2 times greater than those of non-reproducing mammals during summer. On average, predicted metabolic rates during lactation were not significantly greater than during winter, but for some individual species they clearly were.
4. It is suggested that neither the Reallocation nor the Increased Demand Hypothesis can fully explain seasonal reproductive patterns in temperate mammals.     

Bird diversity and environmental gradients in Britain: a test of the species–energy hypothesis

1.  We tested the species diversity–energy hypothesis using the British bird fauna. This predicts that temperature patterns should match diversity patterns. We also tested the hypothesis that the mechanism operates directly through effects of temperature on thermoregulatory loads; this further predicts that seasonal changes in temperature cause matching changes in patterns of diversity, and that species' body mass is influential.
2.  We defined four assemblages using migration status (residents or visitors) and season (summer or winter distribution). Records of species' presence/absence in a total of 2362, 10 × 10-km, quadrats covering most of Britain were used, together with a wide selection of habitat, topographic and seasonal climatic data.
3.  We fitted a logistic regression model to each species' distribution using the environmental data. We then combined these individual species models mathematically to form a diversity model. Analysis of this composite model revealed that summer temperature was the factor most strongly associated with diversity.
4.  Although the species–energy hypothesis was supported, the direct mechanism, predicting an important role for body mass and matching seasonal patterns of change between diversity and temperature, was not supported.
5.  However, summer temperature is the best overall explanation for bird diversity patterns in Britain. It is a better predictor of winter diversity than winter temperature. Winter diversity is predicted more precisely from environmental factors than summer diversity.
6.  Climate change is likely to influence the diversity of different areas to different extents; for resident species, low diversity areas may respond more strongly as climate change progresses. For winter visitors, higher diversity areas may respond more strongly, while summer visitors are approximately neutral.     

CLONAL DIVERSITY IN HIGH-ARCTIC POPULATIONS OF DAPHNIA PULEX,A POLYPLOID APOMICTIC COMPLEX

Based largely on analogy with latitudinal trends in species diversity, it has been proposed that levels of genotypic (clonal) diversity in parthenogenetic populations from high latitudes should be lower than those in populations from the temperate zone or the tropics. Prior studies have shown that low-arctic populations of obligately asexual Daphnia pulex are less clonally diverse than temperate-zone populations. To test for the existence of a latitudinal trend, an allozymic survey of obligately parthenogenetic populations of D. pulex was conducted at a site in the Canadian high-arctic. The study revealed the presence of 75 clones in 179 tundra ponds that were surveyed. On average, 4.5 clones coexisted in single ponds with a range of 1–14 clones. These diversity values are as great (or greater) than those observed in more southerly populations and conflict with the notion of reduced levels of genetic variation in arctic populations. Mechanisms that may influence genetic (clonal) diversity in apomictic complexes are discussed.     

Long-term stability in the richness and structure of helminth communities in eels,Anguilla anguilla,in Lough Derg,River Shannon,Ireland

A data set on intestinal helminth parasites was collected in the course of an 18 year investigation into the biology of eels in Meelick Bay, Lough Derg, River Shannon. This was used to test two hypotheses relating to the composition and structure of intestinal helminth communities, namely that eels in large rivers do not harbour richer and more diverse communities than those in small rivers but that community composition and structure are more stable over time than in small rivers. The helminth community was species poor, with only six species comprising the component community and a maximum infracommunity richness of three species. The community was overwhelmingly dominated by the acanthocephalan Acanthocephalus lucii, reflecting the importance of its intermediate host Asellus aquaticus in the eels' diet. The remaining helminth species contributed to species richness but made very little contribution to community diversity. Population levels of Acanthocephalus lucii fell and remained low between 1992 and 2000, probably reflecting increased movement of eels from other parts of the lough into Meelick Bay. Diversity values were low, but similar to those reported from other rivers in Britain and Europe. The results provided support for both hypotheses and indicated that in respect of richness, diversity and dominance, the helminth communities of eels in the River Shannon were typical of, and comparable to, those of other large rivers throughout Europe.     

Adaptive radiation and ecological opportunity in Sulawesi and Philippine fanged frog (Limnonectes) communities

Because island communities are derived from mainland communities, they are often less diverse by comparison. However, reduced complexity of island communities can also present ecological opportunities. For example, amphibian diversity on Sulawesi Island is lower than it is in the Philippines, but Sulawesi supports a surprising diversity of Sulawesi fanged frogs (Limnonectes). Here we examine molecular, morphological, and geographical variation of fanged frogs from these two regions. Using genealogical concordance, morphology, and a Bayesian approach to species delimitation, we identified 13 species on Sulawesi, only four of which have been previously described. After evolutionary history is accounted for, a model with multiple body size optima in sympatric species is favored over a "random-walk" model of body size evolution. Additionally, morphological variation is higher among sympatric than nonsympatric species on Sulawesi but not in the Philippines. These findings suggest that adaptive radiation of fanged frogs on Sulawesi was driven by natural selection to infiltrate ecological niches occupied by other frog lineages in the Philippines. This supports a role of ecological opportunity in community assembly: diversification in mature communities, such as the Philippines, is limited by a dearth of unoccupied ecological niches. On Sulawesi, evolutionary novelties originated in a predictable and replicated fashion in response to opportunities presented by a depauperate ancestral community.     

Physical variability,diversity gradients and the ecology of temperate and tropical reefs

Traditionally, compared with the tropics, temperate systems are believed to: (i) have environments which are less favourable (i.e. harsher, more variable and less predictable); and (ii) support communities which are less diverse. Explanations for differences between temperate and tropical communities, including differences in diversity, generally rely on the former notion. The evidence for these ideas is, at best, equivocal. Organisms are subjected to physical stresses and disturbances on both temperate and tropical reefs. Communities on temperate reefs are not invariably less diverse than those in the tropics, at least at small spatial scales. Finally, there is as yet little evidence of genuine differences between the ecology of temperate and tropical communities. There is, however, much small-scale, spatial patchiness in the structure of reef communities and their physical environment. This patchiness in structure may result from patchiness in biological factors (e.g. recruitment) or in the physical environment. This small-scale variation in environmental factors may prove to be a more important determinant of community structure than the large-scale, latitudinal trends some ecologists have been obsessed with.     

Adaptative significance of a temperature induced diapause in a cosmopolitan parasitoid of Drosophila

Abstract. 1. We have previously demonstrated pre-pupal diapause in a tropical population of Leptopilima boulardi Barbotin, Carton and Kelner-Pillault (Cynipidae, Hymenoptera), a larval parasitoid of Drosophila melanogaster Meigen. Prepupal diapause was induced by low temperature (17.5°C) but absent at 25°C; it was independent of photoperiod.
2. Four populations which originated from different latitudes (4°S to 44°N) exhibit the same response to temperature without any major genetic geographical variation.
3. In temperate areas, this diapause may permit a phenological and temporal coincidence between the parasitoid and its host whose larval growth is only possible for temperatures above 13°C.
4. The significance of the persistence of this diapause in tropical areas is discussed.     

Effects of insects on primary production in temperate herbaceous communities: a meta-analysis

Abstract.  1. The effects of insects on primary production in temperate herbaceous communities were investigated in a meta-analysis. The following hypotheses were tested: (1) the effect of insects on primary production depends on community type, (2) the effect of insects on primary production varies as a function of productivity, (3) insects have a greater effect on primary production in communities with low species diversity, and (4) insects have a larger effect on primary production during outbreaks.
2. Data were collected from 24 studies in which insecticides were used to suppress insects in self-sown or pastoral communities. Effect sizes were calculated from sprayed and control plot standing crop or yield, expressed as the log response ratio, ln (sprayed plot phytomass/control plot phytomass).
3. There was a significant increase in primary production as a result of insect suppression. Forb-dominated communities showed a more variable response than graminoid communities. During outbreaks, insects had a greater negative impact on primary production. Effect size was unaffected by productivity or plant species richness.
4. Although insects lower primary production in a diversity of temperate herbaceous communities, the basic measures by which such communities are often described have little effect on the proportional impact that insects have on primary production. While outbreaks are significant predictors of higher negative impact on primary production, causes of outbreaks are not always related to traits of the plant community.