Monitoring and manipulation of a sublittoral hard bottom biocoenosis in Balsfjord,northern Norway

Sublittoral hard bottom biocoenoses in Balsfjord, Norway (69°31′ N, 19°1′ E), were monitored using underwater stereophotogrammetry. The study includes manipulation of natural densities of organisms and testing the importance of biological interactions and “key species ” for the structure of biocoenoses. Underwater photography has the advantages of being a non-destructive method, but it is selective because small or hidden organisms cannot always be observed. Field experiments with exclusion of organisms from cages seem suitable for testing hypotheses concerning which animals are “key species ” in certain biocoenoses. Sea-urchins(Strongylocentrotus droebachiensis, S. pallidus) were suspected to be “key species ” in the present study, and their removal from cages caused an increase in abundance of barnacles(Balanus balanoides), the limpetAcmaea testudinalis and algal cover.     

Subtropical coral-reef associated sedimentary facies characterized by molluscs (Northern Bay of Safaga, Red Sea, Egypt)

Summary The shallow marine subtropical Northern Bay of Safaga is composed of a complex pattern of sedimentary facies that are generally rich in molluscs. Thirteen divertaken bulk-samples from various sites (reef slopes, sand between coral patches, muddy sand, mud, sandy seagrass, muddy seagrass, mangrove channel) at water depths ranging from shallow subtidal to 40m were investigated with regard to their mollusc fauna >1mm, which was separated into fragments and whole individuals. Fragments make up more than 88% of the total mollusc remains of the samples, and their proportions correspond to characteristics of the sedimentary facies. The whole individuals were differentiated into 622 taxa. The most common taxon,Rissoina cerithiiformis, represented more than 5% of the total mollusc content in the samples. The main part of the fauna consists of micromolluscs, including both small adults and juveniles. Based on the results of cluster-, correspondence-, and factor analyses the fauna was grouped into several associations, each characterizing a sedimentary facies: (1) “Rhinoclavis sordidula—Corbula erythraeensis-Pseudominolia nedyma association” characterizes mud. (2) “Microcirce sp.—Leptomyaria sp. association” characterizes muddy sand. (3)”Smaragdia spp.-Perrinia stellata—Anachis exilis—assemblage” characterizes sandy seagrass. (4) “Crenella striatissima—Rastafaria calypso—Cardiates-assemblage” characterizes muddy seagrass. (5) “Glycymeris spp.-Parvicardium sueziensis-Diala spp.-assemblage” characterizes sand between coral patches. (6) “Rissoina spp.-Triphoridae —Ostreoidea-assemblage” characterizes reef slopes. (7) “Potamides conicus—Siphonaria sp. 2—assemblage” characterizes the mangrove. The seagrass fauna is related to those of sand between coral patches and reef slopes with respect to gastropod assemblages, numbers of taxa and diversity indices, and to the muddy sand fauna on the basis of bivalve assemblages and feeding strategies of bivalves. The mangrove assemblage is related to those of sand between coral patches and the reef slope with respect to taxonomic composition and feeding strategies of bivalves, but has a strong relationship to those of the fine-grained sediments when considering diversity indices. Reef slope assemblages are closely related to that of sand between coral patches in all respects, except life habits of bivalves, which distincly separates the reef slope facies from all others.     

Macroinvertebrate Diversity in Alpine Lakes: Effects of Altitude and Catchment Properties

Lakes are common features of alpine landscapes, and the attention given to alpine lakes has increased recently in response to increased recognition of the important role that these freshwaters play as sensible indicators of climate change. Despite this general research interest, there is nevertheless a general lack of information about zoobenthos especially of lakes in the Alps, and only few published data are available, which has made it nearly impossible to draw general conclusions in respect to benthic community structure, profundal and/or littoral food webs. This paper aims to explore the relationships between main environmental/catchment properties of 55 lakes and their littoral benthic fauna across three regions of the Alps. We provide updated information on relative abundance, species richness, distribution and ecology of macroinvertebrates which occur and are typical in the littoral of high-mountain lakes of the Alps. These lakes were located in the Lago-Maggiore Watershed (Italy and Switzerland), in South Tyrol (Italy) and in North/East Tyrol (Austria), between 1840 and 2796 m a.s.l., in catchments undisturbed by human activities. As the studied lakes are situated above the tree line, they were characterised by low nutrient levels indicating an oligotrophic status. Lake water chemistry corresponded closely to the geo-lithology of the catchment and some parameters (especially nutrient concentrations) differed between the regions. The macroinvertebrates were dominated by insects which to a high degree were chironomid larvae and pupae. Other insect orders were typical cold stenotherm species of Ephemeroptera, Plecoptera and Trichoptera. Non-insect macroinvertebrates contributed to the 144 taxa found. Other than lake size and catchment area, the faunal parameters exhibited a clearer pattern along altitude. Macroinvertebrates per sample increased with higher elevation, reached their maximum in lakes between 2400 and 2600 m a.s.l., but decreased strongly above 2600 m. The altitudinal pattern of species richness and Shannon diversity resembled each other being highest between 2001 and 2200 m a.s.l., but decreased when going lower and higher, respectively. Various patterns and trends along altitude were also evident when individual groups were analysed within the individual sampling regions. The somewhat conflicting trends of various biocoenotic indices let assume that factors other than altitude are also responsible for the structure of faunal assemblages in the littoral of alpine lakes. Six variables (“bare rocks” and “nitrate”, “alkalinity”, “ammonia” and “peat bog”) were selected by the CCA analysis where these three groups of lakes were identified: (1) lakes with a higher alkalinity (higher pH, conductivity, ion concentration), a higher relative vegetation cover (compared to the “bare rocks” on the opposite side) and lower nitrate levels; (2) lakes with a higher portion of “bare rocks” in their catchments and higher nitrate levels; and (3) a smaller group of lakes with higher ammonia levels and a boggy environment. Geographical patterns seemed to have weak effects on the presence of taxa while catchment properties had evident impacts on macroinvertebrate communities in these lakes. In this way, the present study contributes to the overall understanding of environmental settings and effects on high mountain lake ecosystems and assists in refining research and conservation strategies for an important landscape aspect in the Alps.     

Rare and infrequent southern African grasses: assessing their conservation status and understanding their biology

The taxonomic treatment for the grasses of southern Africa was one of the first to be based on computerised data and the DELTA system. These data, based on over 70,000 herbarium records, are amenable for analysis of species parameters including abundance, frequency and distribution. This information is suitable for the allocation of species into the seven categories of rarity proposed by Rabinowitz using a combination of habitat specificity (“Narrow” or “Broad”), population structure (“Sparse” or “Abundant”) and distribution (“Restricted” or “Widespread”). We compare the species lists obtained for each combination of these three aspects to published Red Data Lists (RDLs) for southern and South Africa. Ninety-three species are placed in the most sensitive or potentially threatened category (Narrow habitat, Sparse populations and Restricted distributions; RSN). This is substantially more than the number of species listed in current RDLs for the region. Chi-square tests indicate a statistically significant bias in taxa from the Fynbos Biome for three of the categories (RSN, RAN and WSN), from the Savanna Biome for the WAN category and from the arid Succulent Karoo and Desert Biomes for the RAB category. Analyses of habitat requirements indicate that many grasses listed (especially those associated with a “Narrow” habitat) are found in some form of wetlands (ephemeral or permanent), especially those at higher altitudes (montane). Despite concerns about the subjective nature in determining the boundaries between the categories, this method is shown to provide a meaningful and valuable list of taxa that require prioritisation for more detailed assessment according to the IUCN criteria.     

The composition of the coastal fish fauna around Elephant Island (South Shetland Islands, Antarctica)

The composition of the coastal fish fauna around Elephant Island (northern South Shetland Islands) was investigated during seven bottom trawl surveys of FRV “Walther Herwig”, FV “Polarstern” and FRV “Yuzhmorgeologiya” from 1981 to 1998. Low-Antarctic (or lesser or peri-Antarctic) fish species were the predominant element of the coastal fish fauna. Large-scale fishing from 1978 to 1981 reduced stock sizes of the most abundant species Champsocephalus gunnari and Notothenia rossii to the extent that only a small fraction of the initial stock remained. After the period of intensive fishing, Gobionotothen gibberifrons became the most abundant species around the island. The by-catch species, which had probably been less affected by harvesting, recovered by the end of the 1980s/beginning of the 1990s. Fish biomass was highest in the 100- to 400-m depth range. An MDS plot revealed the existence of five groups of species that overlapped in their distribution to some extent. One important factor that separated the five groups was depth. Other factors that might have been important in structuring the vertical distribution of the fish fauna, such as bottom topography and sediment type, could not be investigated. Species composition was dominated by a few abundant low-Antarctic species. In four of the five groups, G. gibberifrons was by far the most abundant species, after C. gunnari and N. rossii had been largely eliminated due to fishing. Only in the 100- to 200-m depth range was C. gunnari more abundant than G. gibberifrons. In the 400- to 500-m depth stratum, a high-Antarctic species, Chionodraco rastrospinosus, and Lepidonotothen squamifrons, a species of Patagonian origin which lacks antifreeze glycopeptides, gained some importance. Species richness showed a positive trend with increasing depth. Evenness and Hill's N1 index were highest in the shallowest and deepest depth strata. Hill's N2 index was lowest in depth strata 3 and 4, which had the most even distribution of the abundant fish species. Accepted: 21 May 2000     

Biostratigraphic subdivision and correlation of Uppermost Carboniferous/Lower Permian sediments in the Southern Alps: Fusulinoidean and condont faunas from the Carnic Alps (Austria/Italy), Karavanke Mountains (Slovenia), and Southern Urals (Russia)

Summary In order to establish a refined biostratigraphic subdivision and correlation of the Uppermost Carboniferous/Lower Permian deposits of the Southern Alps (Carnic Alps, Karavanke Mountains; Austria/Italy/Slovenia), two major microfossil groups (fusulinoideans, conodonts) were investigated within the same sample. The fusulinoidean species diversity (71 species, including five new species and three new subspecies) and generic composition were reviewed and complemented. Additionally, the data on fusulinoidean assemblages were supplemented by co-occurring conodont faunas (seven species). Accompanying studies on material from the type sections of the Southern Urals (Russia) were made to improve the biostratigraphic correlation with the Russian standard zonation and to discuss paleobiogeographical aspects of the faunal associations. An integrated microfacies analysis of the sampled material in the Southern Alps serves to evaluate the relationships between certain genera and specific microfacies types. The fusulinoidean fauna of the Lower “Pseudoschwagerina” Limestone is of late Gzhelian age. The Carboniferous/Permian boundary is close to the base of the Grenzland Formation, which covers the entire Asselian and a part of the Sakmarian. The Upper “Pseudoschwagerina” Limestone and Trogkofel Limestone are Lake Sakmarian to Artinskian. The studies sequences in the Karavanke Mountains. formerly known as “carbonate and clastic Trogkofel beds”, correlate to the Lower “Pseudoschwagerina” Limestone, respectively with parts of the Grenzland Formation. Due to the lithologic differences, new formation names (Dolzanova Soteska Fm., Born Fm.) were introduced for the so-called “Trogkofel” Limestone along the Dolzanova Soteska. Whereas late Gzhelian/Asselian fusulinoidean faunas of the Southern Alps correspond to the Southern Uralian faunas to a large extent, Sakmarian and Artinskian faunas reveal an increasing divergence in species and genus composition. Climatic as well as geographic barriers may have prevennted the dispersal of Paleotethyan taxa into the Southern Urals. Biostratigraphic correlation of Sakmarian to Artinskian deposits is therefore possible only on the basis of the sparse conodont faunas.     

Responses of mobile epifauna to small-scale seagrass patchiness: is fragmentation important?

Habitat fragmentation is a process involving splitting of continuous habitats into smaller, and more isolated habitat patches. To assess the effects of small-scale habitat patchiness and isolation without the confounding effect of habitat loss on benthic macrofauna, two field experiments were conducted in the Archipelago Sea, SW Finland. Using artificial seagrass units (ASUs) we contrasted continuous patches (“C”) with fragmented patches (“F”) of the same combined area as the continuous patches. The fragmentation treatment involved two isolation distances (0.5 and 3.0 m) between the ASUs (“F 0.5”) and (“F 3.0”). This design was repeated in two consecutive experiments where the patch area was 0.25 and 0.0625 m², respectively. Mobile epifauna were allowed to colonize patches for 12 days in both experiments. In both experiments, the total epifaunal density was significantly higher in the “F 0.5” treatment than in the “C” treatment, and the three dominant taxa showed positive or neutral responses to the habitat configuration. No fragmentation effect on the number of species was detected in either of the experiments, but fragmentation had a negative effect on the epifaunal diversity (Shannon’s H′) in the experiment with the largest patch area. Epifaunal diversity was significantly lower in “F 3.0” treatment than in “C” or “F 0.5” treatments in the first experiment, indicating stronger effect of isolation instead of fragmentation per se. Edge effects were indirectly tested by comparing epifaunal densities with patch edge:area ratios. The results suggest that edge effects may have a more important role than patch size for the total densities of epifaunal taxa, and that small, isolated patches have equal or higher habitat value compared to larger fragments.     

Echiniscus corrugicaudatus (Heterotardigrada; Echiniscidae) a new species from Ellsworth Land, Antarctica

Echiniscus corrugicaudatus sp. nov., (Heterotardigrada; Echiniscidae) was found in the limited vegetation from the inland nunataks of Ellsworth Land, West Antarctica. The tardigrade fauna of this a rarely explored region shows limited overlap with the fauna from the maritime or coastal continental Antarctic. This species is placed within the Echiniscus “arctomys-group” based on the characteristic of, “a lack of body appendages other than cirrus A”. It has less well-defined edges to the dorsal plates than other species within the group and distinct ridges on the caudal plate. Males were found in the population indicating gonochoristic reproduction, and a large number of juveniles suggesting an over-wintering strategy of eggs or a biennial population over-wintering as adults/sub-adults and eggs.     

Small scale gradient effects on isopods (Crustacea: Oniscidea) in karstic sinkholes

We studied abundance and diversity patterns of terrestrial isopod assemblages along a ‘micro-scale’ vertical gradient in sinkholes in the Aggtelek National Park, Hungary. Time restricted manual sampling yielded ten native species, including endemic and rare ones. Along the gradient we found no major differences in species richness and -composition, and abundance decreased from the bottoms to the upper zones of the sinkholes. Species specific habitat preference on a vertical gradient showed two distinct groups by indicator species analysis: occurrence of habitat “generalists” was irrespective of vertical zones while “specialists” were restricted to the bottoms of the dolines. The latter group is formed mainly by rare species. We found that both diversity and evenness of isopod assemblages were highest in the bottom zone. Our results draw the attention to the significance of such common, yet undiscovered surficial depressions that can provide shelters for rare and specialist species and can provide shelter for survival of populations under changing climatic conditions.     

The freshwater aquarium trade as a vector for incidental invertebrate fauna

The aquarium trade has a long history of transporting and introducing fish, plants and snails into regions where they are not native. However, other than snails, research on species carried “incidentally” rather than deliberately by this industry is lacking. I sampled invertebrates in the plankton, and from water among bottom stones, of 55 aquaria from 43 New Zealand households. I recorded 55 incidental invertebrate taxa, including copepods, ostracods, cladocerans, molluscs, mites, flatworms and nematodes. Six were known established non-indigenous species, and eight others were not previously recorded from New Zealand. Of the latter, two harpacticoid copepod species, Nitokra pietschmanni and Elaphoidella sewelli, are not native to or known from New Zealand, demonstrating the aquarium trade continues to pose an invasion risk for incidental fauna. The remaining six species were littoral/benthic rotifers with subtropical/tropical affinities; these may or may not be native, as research on this group is limited. A variety of behaviours associated with the set-up and keeping of home aquaria were recorded (e.g., fish and plants in any home were sourced from stores, wild caught, or both, and cleaning methods varied), which made prediction of “high risk” behaviours difficult. However, non-indigenous species had a greater probability of being recorded in aquaria containing aquatic plants and in those that were heated. Methods for disposal of aquarium wastes ranged from depositing washings on the lawn or garden (a low risk for invasion) to disposing of water into outdoor ponds or storm-water drains (a higher risk). It is recommended that aquarium owners be encouraged to pour aquarium wastes onto gardens or lawns—already a common method of disposal—as invasion risk will be minimised using this method.     

Dive form and function in belugas Delphinapterus leucas of the eastern Canadian High Arctic

The underwater behaviour of 11 belugas or white whales was examined during summer using time-at-depth records relayed by satellite-linked data-loggers. Simultaneous tracking information was obtained for each whale. Eight distinct dive profiles were identified in submergences made to depths of >40 m. Four of these, together comprising 84% of these “deep” dives, were of a square profile. They were characterised by a continuous descent to a particular depth (usually the sea bed), a “bottom phase” at or near that depth, and a direct ascent to the surface. These dives are presumed to be made for benthic foraging. Other, much less common, dive shapes were “V”-shaped, parabolic and trapezoidal. “Shallow” dives (15–40 m depth) were of a variety of shapes, short duration and high average horizontal speeds. Many probably occurred during periods of directed travel. This population of belugas treats most of the water column as dead space separating resources of oxygen and nutrition. Received: 8 January 1998 / Accepted: 27 April 1998     

Selection of indicative taxa for river habitats: a case study on benthic macroinvertebrates using indicator species analysis and the random forest methods

The aim of the study was to evaluate the exclusivity and/or preference of macroinvertebrate taxa for river habitats. Indicator species analysis and random forests methods were applied to the data set of macroinvertebrate samples taken from 58 sampling points. Samples were classified according to habitat types defined by the position in a river channel and local hydraulic characteristics. 86 macroinvertebrate taxa were included in the analyses. High indicative values for habitats (importance value ≥50 and/or indicator value ≥40) were identified for 26 taxa. The results of both methods can be considered similar. Merged habitats of channel margin (margin of main channel and side arms) were mainly defined by “negative” indicator taxa (correct classification of given samples was caused by non-occurrence and low abundances of certain taxa in this habitat). In general, there was only a small group of taxa preferring these habitats. Taxa were not fully habitat specific because they mostly occurred in two or three habitat types. This could be the result of autecological plasticity of individual taxa and the connectivity among habitats. According to the experience from this case study, it can be concluded that both random forests and IndVal methods are suitable for the detection of indicative species, and random forests method has some additional advantages.     

How do follower reef fishes find nuclear fishes?

Among reef fishes, it is common for “follower” individuals to accompany “nuclear” species and to feed on prey uncovered by their foraging. In this study, I examine the cues used by followers to find nuclear fish. A model of a ubiquitous nuclear fish was maintained immobile or moved to disturb the substratum and the number of fish species and individuals attracted was compared to control treatments. The results showed that: 1) bottom disturbance was the strongest attraction factor for follower reef fishes; 2) visual features of the nuclear also attracted follower reef fishes; 3) there was no evidence of an interaction between bottom disturbance and nuclear fish appearance in the attraction of followers, supporting the idea that both factors independently elicit following behaviour by reef fishes.     

Effects of the “Amoco Cadiz ” oil spill on an eelgrass community at roscoff (france) with special reference to the mobile benthic fauna

In October 1977 an investigation was initiated of the qualitative and quantitative composition of the fauna of the eelgrass (Zostera marina) beds at Roscoff. Samples were taken in 2 seagrass beds at different tidal levels in order to follow numerical changes in the course of the year. In March 1978 the area of study was struck by the oil slick of the tanker “Amoco Cadiz ”. For this reason sampling has been continued at the same frequency. The tabulated results show clearly that the oil slick had a profound but selective influence on the various animal groups; some of them disappeared while others were apparently unaffected. Rapid recovery of some species has taken place, but re-establishment of other species, particularly the filter feeders has not been observed. The very diverse amphipod fauna has disappeared, and has been replaced by a population ofPherusa fucicola andGammarus locusta; the latter was absent in the year before the oil disaster took place.     

Abundance and diversity of tidal marsh plants along the salinity gradient of the San Francisco Estuary: implications for global change ecology

From 2003 through 2005, tidal marsh plant species diversity and abundance on historically surveyed vegetation transects along the salinity gradient of the San Francisco Estuary were investigated to establish empirical relationships between plant distributions and environmental conditions, and furthermore to examine and predict past and future plant distribution changes. This study suggests that for most species, salinity is the primary control on plant distribution. Thus, ongoing changes in estuarine conditions (increasing sea level and salinity) are resulting in a complex mix of plant distribution changes. On the low marsh, where sediment salinity is similar to that of ambient water, halophytic species are replacing salt-intolerant taxa. However, on marsh plains, where increased tidal flooding is moderating high salinity (concentrated by evaporation), halophytic “high marsh” species are being replaced by salt-intolerant “low marsh” taxa. Thus, future changes in plant distributions will hinge on whether marsh sediment accumulation keeps pace with sea level rise.     

Domestic Fauna and Anthropochorous Fauna

The term “anthropochorous” can be referred to the fauna which has populations or nuclei of individuals brought to and diffused in geographical areas by the direct or indirect action of humans. This definition therefore implicates the role of humans, either conscious or unconscious, in the alteration of the areas of distribution of the fauna. Hence, all the faunal populations that have originated as a consequence of human intervention fully belong to this category. As well as domestic animals in the strict sense, we can also cite several other “wild” species, such as rats and mice, which at present enjoy an artificial diffusion in areas that are completely extraneous to that of their original distribution.     

Materials towards the revision of the genus Triplophysa rendahl, 1933 (Cobitoidea: Balitoridae: Nemacheilinae): A revision of nominal taxa of Herzenstein (1888) described within the species “Nemachilus” stoliczkae and “N.” dorsonotatus, with the description of the new species T. scapanognatha sp. nova

This study reviews the nominal taxa within the species “Nemachilus” stoliczkae and “N.” dorsonotatus, described by Herzenstein (1888). N. dorsonotatus, N. d. retropinnis, and N. plagiognathus are reviewed within the species Triplophysa stoliczkae; it is suggested that this species is represented by at least 5 subspecies. N. stoliczkae brevicauda, N. s. leptosoma (synonym, N. s. productus), and N. s. crassicauda are considered as valid species, the last 2 are related to the group including the species T. tenuis, T. choprai, T. tenuicauda, and T. yasinensis rather than with T. stoliczkae. It was shown that the “stoliczkae” species group (sensu Prokofiev, 2001) should be divided into three species groups: “stoliczkae” (s. str.), “tenuis,” and “robusta”; their diagnoses and the species composition are presented. A new species from the “stoliczkae” group is described (T. scapanognatha sp. nova), related to T. tanggulaensis (Zhu, 1982). Original Russian Text ? A.M. Prokofiev, 2007, published in Voprosy Ikhtiologii, 2007, Vol. 47, No. 1, pp. 5–25.     

Emergence trap, a new method to survey Limoniscus violaceus (Coleoptera: Elateridae) from hollow trees

The study of insects inhabiting basal hollow trees presents a methodological challenge inducing the fact that there is very little research done on fauna of this habitat. Many endangered saproxylic species only develop in cavities located at ground level. One of the most emblematic species of the kind is the Violet Click Beetle (Limoniscus violaceus), included in Annex II of the UE “Habitats” Directive. Surveys have been conducted in five Natura 2000 areas using a new method to monitor L. violaceus: the emergence traps. A total of 376 beetle species, including 239 saproxylics, have been identified. Five are considered threatened and are registered on the European Red List of saproxylic beetles and three are included in Annex II of the “Habitats” Directive. Among 191 trees studied, 33 revealed the presence of L. violaceus. Sampling efforts required to detect at least one specimen have been evaluated. Our results show that sampling a minimum of 20 hollow trees in April and May with emergence traps is recommended to obtain a meaningful survey on the presence of the Violet Click Beetle.     

Studies of diversity of benthic fauna of lakes in Mari El Republic by rank distribution method in perspectives of application to water quality biological benchmark

The dataset on benthic fauna diversity obtained by ecological monitoring of lakes (Mari El Republic) was analyzed for applicability in water quality biological benchmark. The effect of several parameters on biodiversity were tested: (1) calculation errors in species number definition, (2) application of certain evaluation method of rank distribution parameters, (3) adequacy degree of distribution model, (4) evenness: diversity ratio, (5) hydrochemical parameters of lake, and (6) “sampling site effect” (natural reserve area impact). The biodiversity characteristics were suggested, which highly correlated to obtained data. The critical level for each characteristic was proposed to define favorable and adverse conditions of benthic communities. Practical recommendations were given for using studied parameters in the evaluation of the water quality biological benchmark in Mari El Republic.