Serum electrolytes and skeletal mineralization in hard- and soft-water areas

Serum levels of calcium and magnesium were measured in two Ontario cities that differ widely in the hardness of their local water-supply. The hypothesis being tested was that residents of the city with the hard water-supply (and a low cardiovascular death-rate) would show relatively high serum levels of calcium and/or magnesium. In addition, a comparison was made of the cortical thickness of the second metacarpal bone in the two areas to see if there was any evidence of increased skeletal mineralization in the hard-water area. The results obtained did not support either of these hypotheses, but it is suggested that the failure to demonstrate differences in body-levels of calcium or magnesium may not be incompatible with one (or both) of these water-borne elements functioning as the “water-factor” in cardiovascular disease.     

中国钮虫责属种类记述(襀翅目:鰿科:钮虫责亚科)

记述中国钮虫责属 Acroneuria Pictet昆虫 4种 ,其中包括 2新种 :莫氏钮虫责Acroneuria morsei,sp.nov.和多锥钮虫责 Acroneuria multiconata,sp.nov.。模式标本存扬州大学植物保护系昆虫标本室 ( YU)和西北农林科技大学昆虫博物馆 ( NW-STUAF)。     

The influence of environmental variables on larval growth of stoneflies (Plecoptera) in natural and deforested streams

A total 14 streams located in the Tatra Mts (Slovakia) were investigated. The studied river basins have different deforestation range (0–45.5%) influenced by windstorm. Daily and annual water temperature suggested that in streams overflowing through the area deforested by windstorm the temperature was higher than in selected non-disturbed streams. Higher average nutrient concentrations in samples from these streams are connected with nutrient mobilization from disturbed forest soils after the windstorm. Most of the damaged streams have higher trophic status, including POM and biofilms. The growth of the most abundant larvae increases with deforestation. Growth of species Leuctra rauscheri, Protonemura Montana, and Perlodes intricatus correlates with the sum of daily temperatures over a given time interval. Growth of species Brachyptera seticornis, Leuctra autumnalis and Isoperla sudetica are affected by stream trophy.     

Biodiversity loss in Appalachian headwater streams (Kentucky,USA): Plecoptera and Trichoptera communities

Government and academic studies indicate that many streams in the Appalachian Mountains have degraded biological communities stemming from a variety of regional landuses. Headwater stonefly (Plecoptera) and caddisfly (Trichoptera) assemblages were assessed between 1999 and 2004 in relation to pervasive landuse disturbances (coal mining and residential) in mountainous areas of eastern Kentucky, USA. Indicator metrics (richness, abundance, tolerance, and an observed/expected (O/E) null model) were compared among 94 sites with different land use pressures including least disturbed reference, residential, mining, and mixed mining and residential categories. Thirty-three stonefly species from 26 genera and 9 families were identified; Leuctra, Acroneuria, Haploperla, and Isoperla comprised the core genera that commonly decreased with disturbance. Caddisflies were represented by 48 species, 32 genera, and 14 families. Core caddisfly genera (Neophylax, Pycnopsyche, Rhyacophila, Lepidostoma, and Wormaldia) were extirpated from most disturbed sites. Species richness was significantly higher at reference sites and reference site mean tolerance value was lowest compared to all other categories; relative abundance of both orders was variable between disturbance groups. Non-metric multidimensional scaling (for riffle-dwelling stonefly and caddisfly genera) clustered reference sites distinctly from most other sites. The O/E index was highly correlated with individual habitat and chemical stressors (pH, conductivity) and on average, it estimated ~ 70% loss of common stoneflies and caddisflies across all disturbed landuse categories. Expected plecopteran and trichopteran communities were radically altered in streams draining mining and residential disturbance. Long-term impacts incurred by both landuses will continue to depress these vulnerable indigenous fauna.     

Filters and templates: stonefly (Plecoptera) richness in Ouachita Mountains streams, U.S.A.

1.  We collected adult stoneflies periodically over a 1-year period at 38 sites in two headwater catchments in the Ouachita Mountains, Arkansas, U.S.A. The 43 species collected were a subset of the Ozark-Ouachita fauna and the much larger fauna of the eastern U.S.A. We estimated 78–91% species coverage in the two catchments using jackknife extrapolation of species richness from our survey.
2.  Many streams, especially small ones, lacked surface water for months, but others, both small and large, flowed permanently.
3.  Using published regional presence–absence and coarse ecological data in a discriminant function analysis (DFA), we identified stream size (negative) and regional frequency of occurrence (positive) as predictors of presence in these headwater catchments. For the combined catchments, the extrapolated richness (51 spp.) was similar to an estimate (48 spp.) based on predicted absences from DFA and the Ouachita provincial total of known stonefly species (57 spp.).
4.  Local species richness (1–27 spp. per site) was correlated strongly with stream size (catchment area) but was independent of stream drying. Generic richness was correlated negatively with stream drying and positively, but less strongly, with stream size.
5.  Regionally endemic stoneflies dominated in drying streams, and widely distributed species dominated in more permanent streams. The composition of stonefly assemblages was associated with regional factors (species pools, regional abundance, evolution of tolerant endemic species, regional climate) and local factors (drying, stream size).     

Plecoptera response to acidification in several headwater streams in the Vosges Mountains (northeastern France)

Plecoptera are among the most threatened aquatic invertebrates in industrialised countries as they are very sensitive to many types of pollution. On the contrary, stoneflies are largely considered as tolerant to acidification in comparison with many other macroinvertebrate groups. However, an understanding of Plecoptera responses to acidification is lacking due firstly to the complexity of most Nemouroidea specific determinations at larval instars and secondly to the poor Plecoptera diversity in North European countries, where most studies on acidification impact were performed. In the present study, we assess the response of Plecoptera species and species assemblages to freshwater acidification by collecting adults, allowing specific determination. Significant relationships were observed between richness and several chemical parameters. The relative abundance of several species was also significantly correlated to pH and acid neutralizing capacity (ANC). The results highlight the importance of species determination to assess the effects of acidification. Direct effects, i.e. ecotoxicological effects, were not the only factor leading to the erosion of Plecoptera diversity. Finally, this study tends to demonstrate that this order of aquatic insects is more severely affected by freshwater acidification than commonly believed.     

Response of secondary production by macroinvertebrates to large wood addition in three Michigan streams

1. We measured responses in macroinvertebrate secondary production after large wood additions to three forested headwater streams in the Upper Peninsula of Michigan. These streams had fine‐grained sediments and low retention capacity due to low amounts of in‐channel wood from a legacy of past logging. We predicted that wood addition would increase macroinvertebrate secondary production by increasing exposed coarse substrate and retention of organic matter. 2. Large wood (25 logs) was added haphazardly to a 100‐m reach in each stream, and a 100‐m upstream reach served as control; each reach was sampled monthly, 1 year before and 2 years after wood addition (i.e. BACI design). Macroinvertebrate secondary production was measured 1 year after wood addition in two habitat types: inorganic sediments of the main channel and debris accumulations of leaf litter and small wood. 3. Overall macroinvertebrate production did not change significantly because each stream responded differently to wood addition. Production increased by 22% in the main‐channel of one stream, and showed insignificant changes in the other two streams compared to values before wood addition. Changes in main‐channel macroinvertebrate production were related to small changes in substrate composition, which probably affected habitat and periphyton abundance. Macroinvertebrate production was much greater in debris accumulations than in the main‐channel, indicating the potential for increased retention of leaf litter to increase overall macroinvertebrate production, especially in autumn. 4. Surrounding land use, substrate composition, temperature and method of log placement are variables that interact to influence the response of stream biota to wood additions. In most studies, wood additions occur in altered catchments, are rarely monitored, and secondary production is not a common metric. Our results suggest that the time required for measurable changes in geomorphology, organic matter retention, or invertebrate production is likely to take years to achieve, so monitoring should span more than 5 years, and ecosystem metrics, such as macroinvertebrate secondary production, should be incorporated into restoration monitoring programs.     

Reproductive biology of mixed-species populations of Goodyera (orchidaceae) in northern Michigan

The reproductive biology ofGoodyera oblongifolia, G. repens var.ophioides andG. tesselata is discussed with emphasis on the reproductive isolating mechanisms operating in mixed-species populations. Cytology, phenology and pollination of the above three species were studied. Artificial hybridizations were made of these three species and ofG. pubescens. Results show that within mixed-species populations,G. oblongifolia,G. repens var.ophioides andG. tesselata are not completely isolated reproductively, and hybridization does occur. The deleterious effects of the loss of gametes to interspecific crosses are reduced by seasonal isolation, perennial growth and geitonogamous seed production which is encouraged by self-compatibility and clonal growth. Thus, hybridization in mixed-species populations is apparently kept to levels low enough to allow the species to maintain their identities.     

A Revision of South American Austroperlidae (Plecoptera)

The South American Austroperlidae are revised. Klapopteryx kuscheli and Penturoperla barbata are redescribed. The male and nymph of K. armillata are described and figured for the first time and the female genitalia redescribed. K. costalis is declared a junior synonym of K. armillata. K. barilochensis is transferred to Andesobius new genus and redescribed. New family and generic diagnoses and keys to genera and species are given.     

A comparison of three methods to investigate the diet of breeding double-crested cormorants (Phalacrocorax auritus) in the Beaver Archipelago, northern Lake Michigan

In order to understand the role of waterbirds in aquatic food webs it is important to first get an accurate depiction of their diet. Three methods of dietary assessment (pellets, regurgitate and stomach contents) are compared here for breeding double-crested cormorants (Phalacrocorax auritus) of the Beaver Archipelago, northern Lake Michigan. By numerical frequency (percent number), each method yielded different depictions of the diet. However, in terms of presence and absence (percent frequency) of possible prey types, stomach content data did agree with both pellets and regurgitate data. However, differences were noted between regurgitate and pellets. In terms of biomass measured (percent biomass) in regurgitate and stomachs, data gathered agreed. In essence, pellets underestimate the importance of alewife (Alosa pseudoharengus) and overestimate the importance of crayfish (Orconectes sp.) in the diet when compared to both regurgitate and stomach analysis. The non-lethal method of regurgitate collection and analysis appears most practical in assessing cormorant diet in this system. In combination with information on avian foraging ecology and prey populations, these data may be used to investigate the relationships among cormorants and their prey, and lead to a better understanding of Great Lake food web dynamics.     

Food preference, growth and maturation of Nemurella pictetii (Plecoptera: Nemouridae)

1. The stonefly Nemurella pictetii has a highly variable life cycle and is semi‐ and uni‐, but also plurivoltine in different geographical areas. 2. The influence of the type of food on growth and maturation of larvae was studied in laboratory experiments. Food preference was also assessed. 3. Larvae of N. pictetii are strongly opportunistic feeders utilising a broad range of food sources. However, biofilm was preferred over detritus (conditioned leaves), green algae and animal food. The highly mobile larvae quickly found the preferred food. Larvae fed on biofilm grew and developed significantly faster than larvae fed on conditioned leaves. 4. Larval growth and maturation in experiments as well as in the field differed with available food qualities. Phases of faster growth and maturation corresponded well with maximum availability of biofilm in the field. This contributes to the interpretations of differences in life cycles in the field.     

Life cycle and production of Skwala parallela (Frison) (Plecoptera: Perlodidae) in a Colorado montane stream

The life cycle and production of Skwala parallela, a perlodid stonefly, was investigated in a third-order Colorado montane stream. The species exhibited a univoltine life cycle with a distinct cohort. Small nymphs appeared in May. Rapid growth was exhibited throughout summer and autumn. During winter, growth slowed somewhat but was continuous until April. Maximum density of 34 nymphs/m² occurred in July. Based upon the instantaneous growth method, annual production was 395.3 mg/m² or 3.95 kg/ha dry weight with a P/B ratio of 4.4     

Relationship between benthic insects (Ephemeroptera, Plecoptera, Coleoptera, Trichoptera) and temperature in small and medium-sized streams in Germany: A multivariate study

Benthic insect communities (Ephemeroptera, Plecoptera, Coleoptera, Trichoptera) were studied together with water temperature and environmental parameters in streams between June 2000 and June 2001. The sampling area consisted of 20 sites in small and medium-sized streams located in the lower mountainous area of Central Europe. Temperature was recorded nearly continuously and several physicochemical and environmental variables were assessed. Macroinvertebrates were sampled both in spring and summer. Data-sets of species abundance and occurrence were analysed using multivariate techniques and were correlated to the thermal and environmental conditions of the streams. The temperature preferences of the species were compared to published data-sets on their autecological characteristics. Up to 29% of the variability in the Ephemeroptera, Plecoptera, Trichoptera and Coleoptera community was explained by summer temperature variation in the data-sets for both small and medium-sized streams. A smaller, but significant part of the variability in species distribution was explained by conductivity, substratum type, and the percent coverage of local riparian forest. Compared to small streams, temperature was less important for the macroinvertebrate composition in medium-sized streams. This result is likely due to the more tolerant, eurythermic species composition in larger streams. A total of 33 Ephemeroptera, Plecoptera, Coleoptera and Trichoptera taxa were positively correlated and 28 taxa were negatively correlated to summer temperature patterns. The temperature preferences of taxa considered in this study were related to species traits, such as egg dormancies and life cycle plasticity.     

Nymphal trophic behaviour of two Nemouridae species (Insecta,Plecoptera) in the Curone creek (northern Apennines,Italy)

Feeding habits of the Euholognathan stoneflies Nemoura hesperiae and Amphinemura sulcicollis are studied in a little stream located in northern Italy. The former fed mainly on coarse particulate organic matter (CPOM), together with detritus, while the latter fed principally on detritus and, in a lower concern, on CPOM. Thus they can be catalogued fundamentally as shredder and collector‐gatherer, respectively. Shifts in diet composition were detected in relation to size in both taxa. Probably niche overlapping does not exist despite both species having similar size and nymphal development duration, and coinciding in time. This work supports that, though functional feeding groups are very useful, they should not be inferred from related species or higher taxonomical levels. Even intra‐population differences and ontogenetic shifts should be considered in fine scale studies.     

Tropical acid streams – the chironomid (Diptera) response in northern Australia

1. Chironomidae, sampled by interception of drifting cast pupal exuviae, responded to inputs of acid, heavy metal-rich waters in a seasonally flowing tropical stream in northern Australia.
2. Responses included gain of distinctive (indicative) taxa, loss of some species typical of pristine conditions, and increase in species richness.
3. Experimental manipulation (upstream diversion) of a mine adit entry showed that these responses were the result of change in water quality.
4. The higher species richness at low pH, which is contrary to temperate studies, may be explained by the large tropical (Australian and south-east Asian) pool of species tolerant of naturally occurring acidic aquatic habitats.
5. The structure and responses of the exuvial-assessed chironomid community matched long-term larval data.     

Tropical acid streams – the chironomid (Diptera) response in northern Australia

1. Chironomidae, sampled by interception of drifting cast pupal exuviae, responded to inputs of acid, heavy metal-rich waters in a seasonally flowing tropical stream in northern Australia.
2. Responses included gain of distinctive (indicative) taxa, loss of some species typical of pristine conditions, and increase in species richness.
3. Experimental manipulation (upstream diversion) of a mine adit entry showed that these responses were the result of change in water quality.
4. The higher species richness at low pH, which is contrary to temperate studies, may be explained by the large tropical (Australian and south-east Asian) pool of species tolerant of naturally occurring acidic aquatic habitats.
5. The structure and responses of the exuvial-assessed chironomid community matched long-term larval data.     

A New Apterous Leuctra (Plecoptera) Species from Turkey

Leuctra boluensis sp.n., which is the only apterous stonefly from Turkey, is described and illustrated. The ecology is also given.     

Size relationships of Acroneuria californica (perlidae,plecoptera) and its prey

Summary Acroneuria californica has a life cycle of three years and nymphs of quite different sizes were present throughout the year. The annual cycle of feeding habits is described. Diptera were heavily consumed in summer and Trichoptera in winter. Ephemeroptera were a regular component of the diet with minor peaks in spring and late summer. A positive relationship is shown between the size of stonefly nymphs and their prey of three insect orders. A size-dependent relationship is also shown in the qualitative nature of the diet. Trichoptera were eaten by large nymphs, Ephemeroptera by those of intermediate size and Diptera by the smallest nymphs. Interactions between prey size and seasonal availability are discussed.

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Zusammenfassung Acroneuria californica hat einen dreijährigen Lebenszyklus, und Nymphen von ganz verschiedener Grösse waren anwesend während des Jahres. Der jährliche Zyklus der Nahrungsgewohnheiten ist beschrieben. Im Sommer wurden Diptera bevorzugt, im Winter Trichoptera. Ephemeroptera waren ein regulärer Teil der Nahrung mit kleinen Spitzen im Frühling und im Spätsommer. Ein positives Verhältnis ist aufgezeigt zwischen der Grösse von Nymphen und ihrer Beute von drei Insektenordnungen. Ein grössenabhängiges Verhältnis ist auch aufgezeigt in der qualitativen Art der Nahrung. Trichoptera wurden von grossen Nymphen verzehrt, Ephemeroptera von mittleren und Diptera von den kleinsten. Die Wechselwirkung zwischen Grösse der Beute und jahreszeitlicher Verfügbarkeit wird diskutiert.

     

Diatoms and water quality in lowland streams in the province of northern Brabant (The Netherlands)

Summary The diatoms of two Dutch lowland streams were studied. The stream Beerze is heavily polluted by the effluent of a sewage treatment plant, causing a change in the pH from less than 4 to more than 6. The acidobiontic diatomEunotia exigua is replaced by more alkaline and eutraphentic species such asGomphonema parvulum, Cyclotelia meneghiniana andFragilaria capucina. The Simpson diversity index rises from 0.2 in the upper course to 0.9 in the middle course and maintains this level in the lower course.From stream Rosep samples of 1919–1930 and recent ones were studied. This stream is polluted now by agriculture. In the earlier samples oligo-mesotraphentic species dominated (Eunotia spp.,Melosira distans). In 1976 the species of organically polluted waters were most abundant. The oligo-mesotraphentic species were hardly recovered.In spite of the severe pollution the number of rare species in both streams is still high, compared with that in stagnant waters. Only in mesotrophic moorland pools and mesotrophic quivering bogs, which are situated in trophic gradients just like both streams, a comparable number of rare species may be found.     

A New Synonymy in the Genus Pteronarcys (Plecoptera: Pteronarcyidae)

Pteronarcys macra Ra, Baik et Cho, 1991 from South Korea is a new junior synonym of P. sachalina Klapálek, 1908. P. sachalina is frequently sympatric with P. reticulata Burmeister, 1839, and new characters to distinguish the larvae of both species are presented.