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1.
Effects on the aquatic biota of lime (CaCO3) application in acidified lakes and streams were studied in a number of waters. After treatment, lime-sensitive species of mosses (Sphagnum spp.) decreased, but species such as Potamogeton natans and Myriophyllum alterniflorum seemed to be favoured. A few years after liming species composition and diversity of phytoplankton, zooplankton and benthic insect larvae were almost identical to that found in oligotrophic and non-acid lakes. Molluscs and benthic crustaceans may have difficulties recolonizing. Reproduction of remaining species of fish was successful as soon as pH increased. High survival of larvae and fry can result in some extremely rich year classes with slow individual growth. In most cases restocking of depleted fish stocks was successful. 相似文献
2.
Rudi Verovnik Miloš Popović Martina Šašić Sylvain Cuvelier Dirk Maes 《Journal of Insect Conservation》2014,18(4):675-682
The Brown’s Grayling (Pseudochazara amymone) is one of the most enigmatic and sought after species among European butterflies. Hiding its exact distribution for almost 40 years with the idea of protecting it, resulted in an increasing collector’s interest, with market prices reaching up to 1,000 euro for a single female after its discovery in Albania. Aiming to demystify this butterfly and enable entomologists and conservationists to see the species in its natural environment, we provide detailed information on its distribution in south-eastern Albania. In addition, we modelled the potential species distribution to facilitate further surveys within its potential range. The modelled range of P. amymone is highly fragmented stretching from the central part of eastern Albania to northern Greece and is strongly bound to ophiolite geological strata. The species was re-assessed as Endangered according to the IUCN criteria, with a predicted population decline due to construction of hydroelectric power plants in one of the locations. We argue that hiding valuable information regarding threatened insect species may have negative effects and we advocate publishing available distribution data so that conservation measures may be undertaken where and when necessary. 相似文献
3.
The present study was aimed to understand the diversity, abundance and distribution of macrozoobenthic community of three selected fishponds differing in sewage intake and culture practices of East Calcutta Wetlands of Kolkata, India, as well as the aquatic ecosystem health of these waterbodies considering benthos as the best indicator of pollution. One year seasonal samplings were done to study the diversity and distribution of macrozoobenthos along with 12 water quality parameters to reflect the ecological conditions and aquatic ecosystem health of these waterbodies through biodiversity indices and statistical analysis (SPSS 10). A total of 27 species of macrozoobenthic organisms belonging to 18 families under four phyla comprising eight major groups viz. Polychaeta, Oligochaeta, Hirudinea, Diptera, Odonata, Gastropoda, Bivalvia and Pisces have been recorded. The diversity of macrozoobenthic fauna of these three waterbodies revealed that Ruby wetland had the highest representation of 24 species followed by Sukantanagar pond (17 species) and Sukantanagar bheri (16 species). The result of Pearson’s correlation coefficient showed that amongst the collected macrozoobenthos the gastropod species, Bellamya bengalensis and Lymnaea acuminata were wetland site-wise significant. The total benthic population and biomass have positive correlation with water transparency and organic enrichment of the waterbody. Shannon Weiner and Margalef’s indices have revealed higher values for Ruby wetland. Biodiversity indices and BMWP Score System designated to benthic organisms, suggested Ruby wetland is healthier than the other two waterbodies, differing in sewage intake and culture practices. 相似文献
4.
L. T. Toth R. van Woesik T. J. T. Murdoch S. R. Smith J. C. Ogden W. F. Precht R. B. Aronson 《Coral reefs (Online)》2014,33(3):565-577
With coral populations in decline globally, it is critical that we tease apart the relative impacts of ecological and physical perturbations on reef ecosystems to determine the most appropriate management actions. This study compared the trajectories of benthic assemblages from 1998 to 2011 in three no-take reserves and three sites open to fishing, at 7–9 and 15–18 m depth in the Florida Keys. We evaluated temporal changes in the benthic assemblage to infer whether fisheries bans in no-take reserves could have cascading effects on the benthos in this region. Coral cover declined significantly over time at our sites and that trend was driven almost exclusively by decline of the Orbicella (formerly Montastraea) annularis species complex. Other coral taxa showed remarkable stasis and resistance to a variety of environmental perturbations. Protection status did not influence coral or macroalgal cover. The dynamics of corals and macroalgae in the 15 years since the reserves were established in 1997 suggest that although the reserves protected fish, they were of no perceptible benefit to Florida’s corals. 相似文献
5.
V. Delucchi 《BioControl》1982,27(1):77-92
There are 109 species of primary and secondary parasitoids associated withZeiraphera diniana Guénée in the Central European Alps. Ninety species are primary, 6 facultative secondary and 13 obligate secondary parasitoids. At family level, the composition of the complex seems to be the same in every outbreak area of the host, with ichneumonids predominating. In the Upper Engadine Valley (Switzerland), where intensive studies were conducted over a period of 3 consecutive outbreak periods (28 years), 65% of the complex is represented. The nomenclature ofZ. diniana parasitoids has been clarified as far as possible. Many species names cited in the literature are synonyms or misidentifications. The complex of parasitoids, together with the associated predators ofZ. diniana, is unable to slow down the rate of density increase of the host in outbreak areas. This fact has stimulated investigations on the most important parasitoid species, i.e.Phytodietus griseanae Kerr. (Ichneumonidae), Sympiesis punctifrons Thomson,Dicladocerus westwoodii West. andElachertus argissa Walker (Eulophidae) over a period of about 10 years. Recent research has demonstrated that immigration ofZ. diniana moths into the outbreak areas during the phase of host density increase is very important. The rate of increase of the natural enemies — which are univoltine —can never equal or exceed that of their host; consequently, control by these natural enemies alone is not possible. 相似文献
6.
Long-term variability of meiobenthos: value,synopsis, hypothesis generation and predictive modelling 总被引:1,自引:1,他引:0
Bruce C. Coull 《Hydrobiologia》1986,142(1):271-279
Few long-term data sets exist for meiofauna. Such data sets are expensive to collect, sort and identify; continuous meiofauna data for a period of greater than two years are limited to one site in Belgium (7 yrs) and two sites (one mud, one sand) in South Carolina, USA (11 yrs). The Belgian study concentrates on benthic copepod abundances whereas data from South Carolina includes major taxa and benthic copepods as well as 4 years of concurrent macrofauna abundance and 3 years of nematode species abundances. In South Carolina, the variance associated with meiofaunal abundance had 6 or 12 month recurrent cycles. Similar analyses on 4 years of macrofauna from the same 2 sites indicated the same cyclicity: one year. Seasonality of the South Carolina major taxa and the 6 most abundant mud copepod species was pronounced at the mud site, but absent or less pronounced at the sand site. Similar results were also found for the nematode species over three years. Variability in meiofaunal abundance was greater year-to-year than within a year. Many such long-term data sets are analysed and abandoned. Herewith, I use our long-term results to hypothesize the causes of the high temporal variance in mud and the lower temporal variance in sand. Is it because the mud fauna is controlled by seasonal inputs of natant predators while at the hydrodynamically active sand site temporal variability is homogenized by constant physical activity? By appropriate statistical modelling long-term data sets can also be used to assess the appropriateness of the sampling schedule (spatial and temporal) and as a predictor of future trends. 相似文献
7.
Since 2007, the ArcticNet and CHOne programmes have allowed researchers, through oceanographic surveys on the ‘NGCC Amundsen’, to collect yearly benthic samples in the Canadian High Arctic. From the Beaufort Sea to the Bay of Baffin, more than 262 samples have been collected and analysed to provide essential data to explain patterns of biodiversity in the Canadian Arctic archipelago. Whereas common species are well known, other more rare species belonging to a few minute species groups, with debatable taxonomy, were set aside for further analyses. Focusing on Syllidae (Annelida, Polychaeta), we found and describe here Streptospinigera niuqtuut sp. nov. from muddy habitats of bathyal Arctic and continental slope beds of northern Atlantic coasts of United States between depths of 169 and 707 m. S. niuqtuut differs from congeneric species by unique dorsal simple chaetae of 1–5 chaetigers dorsally curved and distally rounded, with some sub-distal serration. This species may have frequently been reported from the region as Syllides longocirrata Ørsted 1845 but in fact are species of the genus Streptospinigera Kudenov 1983. We also transfer Streptosyllis templadoi San Martín 1984 to this genus and provide herein a key for the identification of all species of the genus. 相似文献
8.
The South American cichlid fish, Acarichthys heckelii, is one of many exotic species established in Singapore’s artificial freshwater habitat; forming the only recorded population outside its native distribution. The discovery of an A. heckelii individual in a sensitive natural waterway (Nee Soon Swamp Forest) prompted this study, which aimed to investigate the distribution, diet, growth and reproductive ecology of the fish, as well as its possible route of introduction. We found that A. heckelii is largely restricted to artificial freshwater bodies, although a sizable established population occurs in a modified waterway connected to Nee Soon Swamp Forest. Gut contents revealed that the fish fed mainly on benthic algae and macroinvertebrates, the latter occurring in higher frequencies in larger individuals. While unable to ascertain clear seasonality in its breeding, we observed a peak in reproductive investment coinciding with the Northeast monsoon, indicating possible life history adaptations. Genetic comparisons of the cytochrome b mitochondrial marker between individuals from South America, Singapore and the ornamental fish trade shows that the A. heckelii populations in Singapore’s fresh waters are more closely related to fishes in the ornamental fish trade than the native population in South America, corroborating anecdotal evidences identifying aquarists as the source of local releases. Our findings also demonstrate the viability of the ornamental trade as an avenue of species introduction and the potential invasiveness of A. heckelii. 相似文献
9.
A systematic study of more than 15,000Myriophyllum specimens from 189 North American herbaria yielded 63M. quitense specimens. Late 19th century collections were made from Henry's Fork of the Snake River in Jefferson County, Idaho, in 1872, from Santa Cruz Creek, Tucson, Pima County, Arizona, in 1881, from Yellowstone Lake in 1885, and from Crook County, Oregon, in 1894. Twentieth century collections have been made from Yellowstone National Park, at several sites along the Snake River in Idaho, in Summit County, Utah, in Lassen and Shasta counties of northern California, at numerous sites along the Deschutes River, and in Benton County, Oregon, and at three sites in Washington. We contend that the species was introduced into North America by migratory waterfowl more than 100 years ago. Only in the Yellowstone Lake and numerous Deschutes River habitats in which populations now exist are environmental conditions conducive to full morphological development of the species in North America. 相似文献
10.
The species composition of centric diatoms from Lake Frolikha (Transbaikal area) has been studied. The lake is located on the eastern shore of Lake Baikal and connected with it by a river. Twenty-three species of Centrophyceae from 7 genera (Aulacoseira, Cyclostephanos, Cyclotella, Discostella, Handmania, Pliocaenicus, and Stephanodiscus) have been found. The most represented genus is Aulacoseira (11 species). Fifteen species and 4 genera are new for the lake record. All revealed species are known in other lakes of the Baikal region; however Baikal endemics are absent in Lake Frolikha. The flora of centric diatoms in Lake Frolikha can be divided into two groups. The first group includes taxa common in Lake Baikal, and the second group includes taxa not typical for Lake Baikal. The level of differences between flora in Lake Baikal and Lake Frolikha is high (43%) despite the close location and connection to the river. An analysis of distribution of interesting species in Asia is presented. 相似文献
11.
Caryopsis and spikelet fork remains of Dasypyrum villosum (L.) Coss. & Durieu ex P. Candargy have been recovered from a Hallstatt period archaeobotanical assemblage (ca. 900/800–450 cal. bc) in western Hungary (Carpathian basin). The presence of D. villosum has not been reported previously from any Hungarian archaeological sites, however there are accounts of its possible occurrence from the Neolithic, the Bronze and Iron Age in northern Serbia. The exact identification of the species has been hindered by its morphological similarity to wild rye and wheat species, as well as to Secale cereale L. and Triticum timopheevii Zhuk. ssp. timopheevii. D. villosum has been found growing at seven locations in Hungary during the past 100 years. Most of these occurrences do not exist today, and the species is not considered indigenous to the present Hungarian flora. The new finds of this species from an Iron Age feature dated to 702–696 cal. bc in western Hungary leave doubts as to whether it is indigenous or not, and should encourage archaeobotanists to consider the possibility of the occurrence of this species on other sites. 相似文献
12.
Julian A. Steyermark 《Brittonia》1981,33(3):385-400
Collections from French Guiana, Amazonian Brazil, and Colombia taken in the last 20 years include new species in the following genera:Duroia, Pagamea, Psychotria, Randia, Retiniphyllum, Rudgea, Sabicea, Sipanea, andSphinctanthus. Twenty-one new species are described and five are illustrated. 相似文献
13.
C. Prada M. B. DeBiasse J. E. Neigel B. Yednock J. L. Stake Z. H. Forsman I. B. Baums M. E. Hellberg 《Coral reefs (Online)》2014,33(4):1019-1030
Coral species are difficult to discern because of their morphological plasticity, long generation times, and slow rates of mitochondrial DNA evolution. Among Caribbean representatives of the genus Porites are three named species (P. divaricata, P. furcata, and P. porites) with branching colony morphologies whose validity as genetically isolated species has been debated. We present sequence data from the mitochondrial control region, nuclear ITS, and nine single-copy nuclear loci for the Caribbean Porites and a related eastern Pacific species. mtDNA sequences were nearly invariant among the three branching species and their crustose sister P. branneri, and ITS sequences from these four were intermingled. An information theoretic analysis provided no support for upholding the three named Caribbean branching species. Both a clustering analysis and an analysis of molecular variance showed that sequence variation from the three branching forms is partitioned more by geography than by taxonomy. Multi-locus coalescent phylogenetic analysis provided a calibrated estimate for the nuclear DNA substitution rate (0.14 % Ma?1) close to that for other corals. Because no generalities have emerged from genetic investigations of the validity of morphologically defined coral species, the use of single-copy nuclear data is likely to be important in testing problematic species designations. 相似文献
14.
A modification of the general system of classification ofCalliphoridae is proposed in this report. Information about the chromosome complements of about 90 species is provided including references to the earlier literature on chromosomes of this family. With one exception all species studied by us or by earlier investigators have 2n=12. The total complement length of 556 complements from 83 species averaged 66.4 μ. Most species have a short heteromorphic sex pair but the size and morphology vary considerably and one species,Hemipyrellia fernandica, seems to have a quadrivalent sex-chromosome complex in a 2n=14 complement. The autosomal pairs vary in both length and arm ratios between the species but seem to be more stable than the sex chromosomes. Only minor variations were found between different collections of the same species except for two collections ofCalliphora croceipalpis. Although presently available data on the chromosomes of Diptera species suggest that increases in total complement length accompany evolutionary progress, no such general trends were obvious in either the total complement lengths or chromosome morphology, either within or between the tribes ofCalliphoridae. Thus the karyotypical reorganizations in the family have apparently not been directly associated with changes in the general morphological features of the adults which may have responded in these respects more extensively to genetic mutations. 相似文献
15.
InCallithrix, Saguinus, Aotus, andCallicebus other group members than the mother participate in infant care. Differences among these species are obvious in respect to the time of being off any caregiver, and in respect to the carrying position (Aotus andCallicebus). Alloparental care, a basic behaviour pattern in these species, has evolved from the parking behaviour of the prosimians. The infants are «parked» at other group members. 相似文献
16.
Hawis H. Madduppa Neviaty P. Zamani Beginer Subhan Unggul Aktani Sebastian C. A. Ferse 《Environmental Biology of Fishes》2014,97(12):1353-1365
Marine fishes reach their highest diversity in coral reef ecosystems, which they utilize as territory, place of refuge and reproduction, and source of food. One type of predation among reef fishes is feeding on coral polyps, and a single, easily identifiable family of fishes, Chaetodontidae, contains the majority of obligate corallivore species. Multiple studies have examined the behaviour and ecology of Chaetodontidae and their relationship with the benthic habitat. However, many questions remain about their feeding ecology and food specifity at the species level. The present study is the first attempt to systematically decipher the feeding behavior of the obligate corallivore, Chaetodon octofasciatus. Field data were collected from four sites in the Thousand Islands, Indonesia, during two sampling campaigns in 2006, covering two seasons and two different depths. A high abundance of C. octofasciatus was positively related to hard coral cover. Out of a total of 57 scleractinian coral genera observed during the study period, 24 were utilized by C. octofasciatus. All fish collected during the study (n?=?36) had >86 % nematocysts in their guts, supporting their classification as obligate corallivores. Based on the Strauss electivity index, C. octofasciatus displayed a preference for the coral genus Acropora at all depths, while preference for Fungia became more marked at greater depth. Both Acropora and Fungia were observed at high density at all sites, with Acropora density decreasing markedly with depth and Fungia density increasing. Bite rates showed an asymptotic relationship to Acropora density, levelling off between 15 and 20 bites/5 min. The existence of a strong relationship with live coral cover and the preference for specific genera such as Acropora designate C. octofasciatus as a potential bioindicator in the Thousand Islands reefs, while making it particular susceptible to the ongoing degradation of reefs in the region. 相似文献
17.
18.
Tamal Mondal C. Raghunathan K. Venkataraman 《Proceedings of the Zoological Society》2014,67(2):136-139
Reefs of Andaman and Nicobar Islands harbour 418 species of scleractinian corals spread over an area of 2,000 km2. In April to May, 2010, due to the delayed onset of the southwest monsoon the sea surface temperature of the coastal and oceanic region increased to 31.7 °C in respect to the earlier record of maximum 29.0 °C during the said period. This resulted in mass bleaching of hermatypic corals during May, 2010. Rapid under water surveys have been conducted in reefs of Andaman and Nicobar Islands to assess the health of corals between May 2010 and August 2011. It is estimated that 76.62 ± (SD) 10.83 % of coral species are bleached up to a water depth of 10–15 m. Species from the genus Acropora appeared more susceptible to bleaching than those belong to the genus Porites. During the month of June 2010 the sea surface temperature was reduced to 29 °C perhaps due to the rainfall which stimulated rebuilding of zooxanthellae population in bleached corals. Recovery of 85.54 ± (SD) 6.33 % of bleached corals was seen during the study period of 11 months after the bleaching event. Porites spp. showed a high recovery rate, while Acropora spp. had the highest mortality rate. Coral mortality can have profound ecological and socio-economical implications and highlights the need for sustained monitoring for coral reef conservation in India. Hence, steps must be taken to improve management tools to protect these resources of global significance. 相似文献
19.
Siméon Tchakonté Gideon A. Ajeagah Dramane Diomandé Adama Idrissa Camara Pierre Ngassam 《Aquatic Ecology》2014,48(4):379-395
Urban land use has increased dramatically over the past few decades, resulting in high variability in nutrients loading which is likely to alter the biological component of urban streams. Freshwater snails and environmental variables that might structure their diversity and distribution were studied from September 2012 to September 2013 in three contiguous watersheds in Douala. Twelve stations were monitored monthly, two of these are located in a suburban forest area, and the rest situated in urbanized and industrialized zones. Snails were collected using a long-handled net (30 × 30 cm side, 400-µm mesh). Meanwhile, measurements of the environmental variables were taken. Ten species were recorded which are as follows: Melanoides tuberculata (Thiaridae); Gabbiella africana (Bythiniidae); Physa acuta, Aplexa sp. (Physidae); Lymnaea natalensis, Lymnaea stagnalis, Lymnaea columella (Lymnaeidae); Biomphalaria pfeifferi, Bulinus forskalii (Planorbidae) and one undetermined taxon of Bythiniidae. All these snails were identified at nine of the ten urban stations; no species being found in suburban stations. These urban streams have very poor health status with highly polluted waters. Among the species found P. acuta (76.95 %), L. natalensis (19.46 %) and M. tuberculata (2.79 %) were the most abundant. Multiple stepwise regression analysis, Spearman correlation test and redundancy analysis showed that snail occurrences and abundances were probably influenced by water temperature, conductivity, suspended solids, alkalinity, nitrites, nitrates, ammonium, phosphates, oxydability, biochemical oxygen demand, rainfall, encumbrance rate of the riverbed and water width. Moreover, snail dynamics showed a seasonal pattern with peak population abundances and recruitment of young generations during rainy season. This malacological survey spotlighted the impacts of anthropogenic activities on snail’s diversity and distribution, with the proliferation of the invasive pulmonate P. acuta in Douala urban streams. 相似文献
20.