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Remaining Species (remaining + species)
Selected AbstractsAbundance and microhabitats of freshwater sponges (Spongillidae) in a Danubean floodplain in AustriaFRESHWATER BIOLOGY, Issue 6 2007IRIS DRÖSCHER Summary 1. This study examined the abundance and distribution of freshwater sponges (Spongillidae) at 32 sites in a floodplain on the Danube within the ,Donau-Auen' National Park east of Vienna, Austria. Ranked from abundant to rare, the species inventory comprised Ephydatia fluviatilis, Spongilla lacustris, Ephydatia mülleri, Eunapius fragilis and Trochospongilla horrida. 2. The presence of hard substratum was essential for the growth of sponges. Timber stands near the water and drifting dead wood increased the abundance of E. fragilis, E. fluviatilis and E. mülleri, whereas stony substrata were important for S. lacustris. A small fraction of E. fluviatilis was collected from macrophytes (Phragmites). 3. Based on the area colonised, the abundance of S. lacustris, E. fragilis and E. fluviatilis was highest (94.2,100% of the total) in floodplain waters where hydrological connectivity with the Danube was low (0,6 days year,1), whereas E. mülleri and T. horrida made up 20.3,35.9% of the total at sites connected for up to 179 days year,1. Moreover, the area colonised by T. horrida at a current velocity >0.20 m s,1 was larger than in the remaining species. Sites with E. mülleri and T. horrida had a higher silicon concentration (0.9 mg L,1) than sites where the remaining three species were collected (0.4,0.6 mg L,1). 4. In most species, the length of macroscleres (the larger spicules) was positively correlated with conductivity and negatively with pH. With respect to aberrant macroscleres, hooks were observed most frequently, whereas the proportion of centrotylotes (ie with the one on more globular swellings along the spicule) was lowest. 5. Freshwater sponges have a great deal of potential as bioindicators and restoration measures that improve floodplain connectivity will favour rare species, such as E. mülleri and T. horrida, while impairing others (e.g. E. fragilis, S. lacustris and E. fluviatilis). [source] Rhinoceros behaviour: implications for captive management and conservationINTERNATIONAL ZOO YEARBOOK, Issue 1 2006M. HUTCHINS All species of rhinoceros are, to varying degrees, threatened with extinction because of poaching, habitat loss, human-rhinoceros conflict, hunting and civil unrest. Clearly the threats facing the five remaining species (Black rhinoceros Diceros bicornis, White rhinoceros Ceratotherium simum, Greater one-horned rhinoceros Rhinoceros unicornis, Javan rhinoceros Rhinoceros sondaicus and Sumatran rhinoceros Dicerorhinus sumatrensis) are anthropogenic. Although many disciplines are important for conservation, understanding the behaviour characteristics of a species should be considered a key component when developing wildlife-management and conservation strategies. A general overview of the behaviour of rhinoceros is presented, addressing ecology and social organization, activity and habitat use, feeding strategies, courtship and reproduction, and anti-predator behaviour. The implications of behavioural studies for successful management and husbandry of rhinoceros in captivity are discussed in sections on group size and composition, enclosure design and enrichment programmes, activity patterns, introductions, reproduction, hand-rearing, and health and stress. Finally, there is some discussion about the implications of this knowledge for in situ conservation in relation to designing protected areas, further aspects of animal health and stress, and reintroduction and translocation. A detailed understanding of rhinoceros behaviour is important for survival both in range-country protected areas and captivity, and such knowledge should be used to provide the most appropriate animal care and environments for these species. [source] Importance of long-term research in classical biological control: an analytical review of a release against the cabbage seedpod weevil in North AmericaJOURNAL OF APPLIED ENTOMOLOGY, Issue 8 2006D. R. Gillespie Abstract:, Cabbage seedpod weevil, Ceutorhynchus obstrictus (Marsham) (Col., Curculionidae), is an invasive alien pest that is spreading in North America. To aid with planning for introductions of European parasitoids in North America, we examined the status of the only classical biological control release against this pest in North America, which in 1949 introduced Mesopolobus morys, Stenomalina gracilis and Trichomalus perfectus (Hym., Pteromalidae). Weevils and parasitoids were reared in 2005 from mass collections of seedpods of Brassica napus, Brassica rapa and Raphanus raphanistrum (Brassicaceae) from 18 sites in the Fraser Valley, near Vancouver, British Columbia, Canada. Of the three European parasitoid species that were originally released, only S. gracilis was found. The predominant hymenopterous parasitoid species were Trichomalus lucidus, S. gracilis, Mesopolobus moryoides (Pteromalidae), Necremnus tidius (Eulophidae) and Eupelmus vesicularis (Eupelmidae). These constituted over 97% of the parasitoids reared, although overall parasitism was low. Only M. moryoides is clearly North American in distribution; other than S. gracilis, the remaining species were either accidentally introduced or are Holarctic in distribution. Based on these results, re-releases of M. morys and T. perfectus in North America should be considered as part of a classical biological control programme. However, redistribution of S. gracilis is not recommended at present because of potential conflicts with biological control programmes against weeds. Ongoing re-examination of classical biological control programmes can further our understanding of failure of release programmes, particularly when re-examination can be made in the light of improved taxonomy and systematics of the target and agent species. [source] ORIGINAL ARTICLE: Cycads in the insular South-west Pacific: dispersal or vicariance?JOURNAL OF BIOGEOGRAPHY, Issue 6 2008Gunnar Keppel Abstract Aim, Cycads constitute an ancient plant group that is generally believed to disperse poorly. However, one group of cycads (subsection Rumphiae) is thought to have dispersed relatively recently from a Malesian source area westwards to East Africa and eastwards into the Pacific, using a floatation-facilitating layer in their seeds. We use morphological and allozyme characters to investigate the relationships among the species within this group and to deduce whether the wide distribution was achieved by recent dispersal (as evidenced by high genetic similarity) or more distant vicariance events (high genetic differentiation). Location, We examined specimens collected throughout the range of subsection Rumphiae, from East Africa through Southeast Asia to Tonga in the South-west Pacific. Methods, We investigated relationships within subsection Rumphiae of the genus Cycas by analysing 18 variable (11 informative) morphological characters and 22 allozyme loci for seven of the 10 species currently assigned to this taxon. Results, Distinctive morphological characters are few and fail to resolve relationships within the group. Allozyme data show that species within this subsection are closely related and suggest that there are two groups within the subsection, one comprising Cycas thouarsii (East Africa) and C. edentata (the Philippines), and the other the remaining species (from Malesia and the Pacific). The Australian species C. silvestris is sister to subsection Rumphiae in the morphological analysis but is closely allied to C. rumphii (nested within the subsection) in the allozyme analysis, suggesting that Rumphiae may be paraphyletic and that characters thought to be taxonomically important may need to be re-evaluated. Main conclusions, Cycads within subsection Rumphiae are closely related, and the wide distribution of this group was probably achieved through relatively recent oceanic dispersal events. Separate events probably account for the dispersal of these cycads into the Pacific and to Africa. The origin and distribution of C. silvestris (Australia) could be explained by a dispersal event from New Guinea or may have resulted from a former land connection between Australia and New Guinea. [source] The biogeography of Gunnera L.: vicariance and dispersalJOURNAL OF BIOGEOGRAPHY, Issue 7 2003Livia Wanntorp Abstract Aim The genus Gunnera is distributed in South America, Africa and the Australasian region, a few species reaching Hawaii and southern Mexico in the North. A cladogram was used to (1) discuss the biogeography of Gunnera and (2) subsequently compare this biogeographical pattern with the geological history of continents and the patterns reported for other Southern Hemisphere organisms. Location Africa, northern South America, southern South America, Tasmania, New Zealand, New Guinea/Malaya, Hawaii, North America, Antarctica. Methods A phylogenetic analysis of twenty-six species of Gunnera combining morphological characters and new as well as published sequences of the ITS region, rbcL and the rps16 intron, was used to interpret the biogeographical patterns in Gunnera. Vicariance was applied in the first place and dispersal was only assumed as a second best explanation. Results The Uruguayan/Brazilian Gunnera herteri Osten (subgenus Ostenigunnera Mattfeld) is sister to the rest of the genus, followed sequentially upwards by the African G. perpensa L. (subgenus Gunnera), in turn sister to all other, American and Australasian, species. These are divided into two clades, one containing American/Hawaiian species, the other containing all Australasian species. Within the Australasian clade, G. macrophylla Blume (subgenus Pseudogunnera Schindler), occurring in New Guinea and Malaya, is sister to a clade including the species from New Zealand and Tasmania (subgenus Milligania Schindler). The southern South American subgenus Misandra Schindler is sister to a clade containing the remaining American, as well as the Hawaiian species (subgenus Panke Schindler). Within subgenus Panke, G. mexicana Brandegee, the only North American species in the genus, is sister to a clade wherein the Hawaiian species are basal to all south and central American taxa. Main conclusions According to the cladogram, South America appears in two places, suggesting an historical explanation for northern South America to be separate from southern South America. Following a well-known biogeographical pattern of vicariance, Africa is the sister area to the combined southern South America/Australasian clade. Within the Australasian clade, New Zealand is more closely related to New Guinea/Malaya than to southern South America, a pattern found in other plant cladograms, contradictory to some of the patterns supported by animal clades and by the geological hypothesis, respectively. The position of the Tasmanian G. cordifolia, nested within the New Zealand clade indicates dispersal of this species to Tasmania. The position of G. mexicana, the only North American species, as sister to the remaining species of subgenus Panke together with the subsequent sister relation between Hawaii and southern South America, may reflect a North American origin of Panke and a recolonization of South America from the north. This is in agreement with the early North American fossil record of Gunnera and the apparent young age of the South American clade. [source] Response of recruitment to light availability across a tropical lowland rain forest communityJOURNAL OF ECOLOGY, Issue 6 2009Nadja Rüger Summary 1. ,Many hypotheses about species coexistence involve differential resource use and trade-offs in species' life-history traits. Quantifying resource use across most species in diverse communities, although, has seldom been attempted. 2. ,We use a hierarchical Bayesian approach to quantify the light dependence of recruitment in 263 woody species in a 50-ha long-term forest census plot in Panama. Data on sapling recruitment were obtained using the 1985,1990 and 1990,1995 census intervals. Available light was estimated for each recruit from yearly censuses of canopy density. 3. ,We use a power function (linear log,log relationship) to model the light effect on recruitment. Different responses of recruitment to light are expressed by the light effect parameter b. The distribution of b had a central mode at 0.8, suggesting that recruitment of many species responds nearly linearly to increasing light. 4. ,Nearly every species showed increases in recruitment with increasing light. Just nine species (3%) had recruitment declining with light, while 198 species (75%) showed increasing recruitment in both census intervals. Most of the increases in recruitment were decelerating, i.e. the increase was less at higher light (b < 1). In the remaining species, the response to light varied between census intervals (24 species) or species did not have recruits in both intervals (41 species). 5. ,Synthesis. Nearly all species regenerate better in higher light, and recruitment responses to light are spread along a continuum ranging from modest increase with light to a rather strict requirement for high light. These results support the hypothesis that spatio-temporal variation in light availability may contribute to the diversity of tropical tree species by providing opportunities for niche differentiation with respect to light requirements for regeneration. [source] Above- versus below-ground competitive effects and responses of a guild of temperate tree speciesJOURNAL OF ECOLOGY, Issue 1 2009K. David Coates Summary 1The neutral theory debate has highlighted the scarcity of robust empirical estimates of the magnitude of competitive effects and responses within guilds of co-occurring tree species. Our analysis quantifies the relative magnitude of all possible pairwise competitive interactions within a guild of nine co-occurring tree species in temperate forests of northern, interior British Columbia, and explicitly partitions the competitive effects of neighbours into the effects of shading versus the residual effects of ,crowding', assumed to reflect below-ground competition. 2Models that treated neighbours as equivalent in their competitive effects were the most parsimonious for the five species with the smallest sample sizes. For the remaining species (samples sizes of > 150 individuals), the best models estimated separate competition coefficients for all nine species of neighbours. We take this as evidence that species do indeed differ in their competitive effects, but that there can be a minimum sample size required to discriminate between them. 3There was a strong size-dependency in potential growth. Six species showed an optimal growth at a size between 5 and 20 cm diameter. Potential growth declined moderately to strongly as diameter increased. Sensitivity to crowding varied as a function of tree size for five of the nine species; however, this response was not consistent by tree species. 4The magnitude of reduction in growth due to crowding was greater on average than the reduction in growth due to shading, except for the two least shade tolerant conifers. Sensitivity to shading among the conifer species was correlated with their shade tolerance. 5The per capita effects of crowding by different species of neighbours varied widely. A large number of the estimated pairwise per capita competition coefficients were very low. The relative magnitude of the strength of intra- versus interspecific competition also varied widely among the tree species. 6Synthesis. Model selection techniques effectively separated above- and below-ground competition in complex forests, and allowed us to assess differences among species in competitive effects and responses. While below-ground effects were strong, they were due to proximity of neighbours from a very specific (and small) subset of strong competitors within the guild. Response to crowding varied with tree size but the nature of the relationship varied widely among the species. [source] Plant functional types do not predict biomass responses to removal and fertilization in Alaskan tussock tundraJOURNAL OF ECOLOGY, Issue 4 2008M. Syndonia Bret-Harte Summary 1Plant communities in natural ecosystems are changing and species are being lost due to anthropogenic impacts including global warming and increasing nitrogen (N) deposition. We removed dominant species, combinations of species and entire functional types from Alaskan tussock tundra, in the presence and absence of fertilization, to examine the effects of non-random species loss on plant interactions and ecosystem functioning. 2After 6 years, growth of remaining species had compensated for biomass loss due to removal in all treatments except the combined removal of moss, Betula nana and Ledum palustre (MBL), which removed the most biomass. Total vascular plant production returned to control levels in all removal treatments, including MBL. Inorganic soil nutrient availability, as indexed by resins, returned to control levels in all unfertilized removal treatments, except MBL. 3Although biomass compensation occurred, the species that provided most of the compensating biomass in any given treatment were not from the same functional type (growth form) as the removed species. This provides empirical evidence that functional types based on effect traits are not the same as functional types based on response to perturbation. Calculations based on redistributing N from the removed species to the remaining species suggested that dominant species from other functional types contributed most of the compensatory biomass. 4Fertilization did not increase total plant community biomass, because increases in graminoid and deciduous shrub biomass were offset by decreases in evergreen shrub, moss and lichen biomass. Fertilization greatly increased inorganic soil nutrient availability. 5In fertilized removal treatments, deciduous shrubs and graminoids grew more than expected based on their performance in the fertilized intact community, while evergreen shrubs, mosses and lichens all grew less than expected. Deciduous shrubs performed better than graminoids when B. nana was present, but not when it had been removed. 6Synthesis. Terrestrial ecosystem response to warmer temperatures and greater nutrient availability in the Arctic may result in vegetative stable-states dominated by either deciduous shrubs or graminoids. The current relative abundance of these dominant growth forms may serve as a predictor for future vegetation composition. [source] Floral free fall in the Swiss lowlands: environmental determinants of local plant extinction in a peri-urban landscapeJOURNAL OF ECOLOGY, Issue 4 2007IVANA STEHLIK Summary 1Local floras are being depleted by a host of human activities, including habitat destruction and fragmentation, eutrophication, and the intensification of agriculture. Species with particular ecological demands or life-history attributes are more prone to extinction than species with a broader niche. 2We used an old herbarium from the municipality of Küsnacht (Swiss lowlands) as a historical record for comparison with contemporary plant diversity. This comparison revealed that 17% to 28% of all vascular plants that occurred between 1839 and 1915 were extinct by 2003. 3Species of different habitats and life-forms had significantly different rates of extinction: wetlands, disturbed sites and meadows lost most species, whereas forests and rocky habitats were least affected; aquatics and annuals were most prone to extinction, geophytes and hemicryptophytes were intermediate, and phanerophytes and chamaephytes were least affected. 4Species adapted to nutrient-poor soils suffered highest extinction in all habitats, indicating that eutrophication poses an urgent threat to species diversity. Light and soil moisture requirements also had significant effects on extinction, but the direction of the effect varied by habitat. 5When species were grouped into IUCN categories of the red list of Switzerland, the rank order of the observed extinction matched the red list assignment. 6Because many of the remaining species had high estimated extinction probabilities and because extinction is often delayed (extinction debt), a substantial part of the remaining flora of Küsnacht is likely to go extinct in the near future. This will increase the dominance of the common species that already comprise 81% of the local flora. 7The rates and patterns of extinction in Küsnacht are probably representative of surrounding Swiss lowlands and peri-urban landscapes in most developed countries. Studies such as ours can serve as a call for action and form a basis for future monitoring of biodiversity. [source] The relationship of oocyte diameter and incubation temperature to incubation time in temperate freshwater fish speciesJOURNAL OF FISH BIOLOGY, Issue 3 2009F. Teletchea Based on the analysis of six egg variables and incubation temperature of 65 temperate freshwater fish species, the possible relationships between oocyte diameter, incubation time and incubation temperature were reassessed and compared to the results obtained from marine fishes. Most freshwater species have eggs (mean ±s.d. 2·19 ± 1·52 mm) larger than marine species, that are chiefly demersal and develop stuck to various substrata, such as plants or rocks. A strong negative relationship was found between incubation time (t, days) and incubation temperature (T, ° C): t = 186·23e,0·197T (r2= 0·87). A strong dependence of incubation time on oocyte diameter (Ø, mm) and incubation temperature was also found and was defined as: log10t= 3·002 + 0·599 log10Ø, 1·91 log10 (T + 2), which explained 92% of the variance of the data set. Five major groups of species were defined based on the principal component analysis (PCA) of four quantitative variables. There were two distinct groups of salmonids, displaying demersal and non-adhesive eggs with a long incubation time at low temperature, the eggs of which required a high number of degree-days. There was a large group of species possessing small, mostly demersal and adhesive eggs developing at high temperature during a short period of time, and requiring a low number of degree-days. Between these two extremes, there was a fourth group displaying intermediate values and a fifth group including three species with large, adhesive and demersal eggs incubating at high temperatures during a short period of time. The burbot Lota lota displayed an unusual combination of variables compared to the remaining species in the data set. [source] A new species of Creagrutus Günther (Teleostei: Ostariophysi: Characiformes), from the upper Rio Paraná basin, central BrazilJOURNAL OF FISH BIOLOGY, Issue 3 2004A. C. Ribeiro Creagrutus varii n. sp. is described based on material from the Rio São Marcos basin, in the upper Rio Paraná system, Goiás State, Brazil. This is the first record of Creagrutus in the upper Rio Paraná. The new species is proposed to be the sister group of the remaining species of Creagrutus. Creagrutus varii differs from congeners in the morphology of the maxilla, primordial ligament, premaxillary dentition and other features. The evolution of premaxillary tooth morphology in Piabina and Creagrutus and the biogeography of the Rio Paranaíba basin are discussed. [source] Effect of germicidal UVC light on fungi isolated from grapes and raisinsLETTERS IN APPLIED MICROBIOLOGY, Issue 3 2007A. Valero Abstract Aims:, To examine how UVC affects the different genera of fungi commonly isolated from grapes, with the aim of understanding changes in mycobiota during grape ripening and possible applications for preventing grape decay during storage. Methods and Results:, Spores of Aspergillus carbonarius, Aspergillus niger, Cladosporium herbarum, Penicillium janthinellum and Alternaria alternata (between 100,250 spores/plate agar) were UVC irradiated for 0 (control), 10, 20, 30, 60, 300 and 600 s. Plates were incubated at 25°C and colonies were counted daily up to 7 days. Alternaria alternata and Aspergillus carbonarius were the most resistant fungi. Conidial germination in these species was reduced by approx. 25% after 10 s of exposure, compared with greater than 70% reduction for the remaining species tested. Penicillium janthinellum spores were the most susceptible at this wavelength. UVC exposures of 300 s prevented growth of all isolates studied, except for Alternaria alternata. Conclusions:, UVC irradiation plays a major role in selecting for particular fungi that dominate the mycobiota of drying grapes. Significance and Impact of the Study:, The UVC irradiation of harvested grapes could prevent germination of contaminant fungi during storage or further dehydration. [source] Conflicting estimates of connectivity among deep-sea coral populationsMARINE ECOLOGY, Issue 2010Karen Miller Abstract Genetic data were used as an indirect means of assessing connectivity among deep-sea coral populations on seamounts and slopes in the Australian and New Zealand region. We sequenced three DNA regions (16S, ITS and Control Region) in nine deep-sea coral species from sites spanning thousands of kilometers. Based on haplotype distributions and AMOVA, we found evidence of genetic subdivision across ocean expanses for three species: the scleractinian Desmophyllum dianthus, and the antipatharians Antipathes robillardi and Stichopathes variabilis. Levels of genetic variation were low for the remaining species, including the reef-forming Solenosmila variablis and Madrepora oculata, and more sensitive molecular markers may be needed to resolve their spatial structure properly. For two species (the scleractinian Stephanocyathus spiniger and the antipatharian Stichopathes filiformis), we found no evidence of genetic subdivision among sites within regions, suggesting sufficient gene flow occurs to maintain genetic homogeneity at scales of tens to hundreds of kilometers. Recognising that some seamount regions and coral populations are, or are not, effectively isolated will be a key component of successful management planning based on marine protected area networks , both within and beyond national jurisdictions. [source] Defoliation and site differences influence vegetative spread in grasslandNEW PHYTOLOGIST, Issue 2 2002G. T. Barthram Summary ,,Plants spread vegetatively at rates that depend on both their own and their neighbours' traits. We tested hypotheses that such rates also interact with defoliation intensity and differ between sites. ,,Well-established monoculture patches (20 × 20 cm) of five grass species were arranged in plots so that every species patch had all the remaining species as neighbours. Sites were in central Scotland, UK, and at a drier location in eastern Scotland. Plots were cut at 3 cm (,short') or 6 cm (,tall'), either uniformly or in a chessboard pattern. ,,Invasiveness and resistance to invasion followed the transitive hierarchy, Agrostis capillaris > Festuca rubra > Lolium perenne = Holcus lanatus > Poa trivialis , except that P. trivialis strongly invaded H. lanatus at the damper, more fertile site. ,Tall' patches spread and intermixed most, independent of species. The effects of cutting neighbouring patches depended on both invading and invaded species' traits. ,,Thus, defoliation altered the relationships between species, as did differences between sites, influencing both the speed and direction of species replacement. [source] Body mass and extinction risk in Australian marsupials: The ,Critical Weight Range' revisitedAUSTRAL ECOLOGY, Issue 1 2009CHRISTOPHER N. JOHNSON Abstract Australian mammals have suffered an exceptionally high rate of decline and extinction over the last two hundred years. Body mass is linked to extinction risk in Australian mammals, but the nature of this association is controversial. A widely held view is that species of intermediate body mass (between 35 and 5500 g, the ,critical weight range', CWR) have declined most severely. However, the existence of the CWR has been disputed. In this paper we clarify the relationship of decline status and body mass in Australian marsupials. We show that the form of this relationship differs for ground-living versus arboreal species, and for species from low versus high rainfall areas. Among ground-living species and those from low-rainfall areas, declines were strongly size-selective and concentrated on species within the CWR. For the remaining species, decline was only weakly related to body mass with no evidence of heightened risk for species of intermediate size. We conclude that for terrestrial species in low rainfall areas, species within the CWR are most at risk of decline and extinction. 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