Diversity Of Invertebrate Communities Research Articles

“Species” Radiations of Symbiotic Dinoflagellates in the Atlantic and Indo-Pacific Since the Miocene-Pliocene Transition

Endosymbiotic dinoflagellates, or "zooxanthellae," are required for the survival of a diverse community of invertebrates that construct and dominate shallow, tropical coral reef ecosystems. Molecular systematics applied to this once understudied symbiont partner, Symbiodinium spp., divide the group into divergent lineages or subgeneric "clades." Within each clade, numerous closely related "types," or species, exhibit distinctive host taxon, geographic, and/or environmental distributions. This diversity is greatest in clade C, which dominates the Indo-Pacific host fauna and shares dominance in the Atlantic-Caribbean with clade B. Two "living" ancestors in this group, C1 and C3, are common to both the Indo-Pacific and Atlantic-Caribbean. With these exceptions, each ocean possesses a diverse clade C assemblage that appears to have independently evolved (adaptively radiated) through host specialization and allopatric differentiation. This phylogeographic evidence suggests that a worldwide selective sweep of C1/C3, or their progenitor, must have occurred before both oceans separated. The probable timing of this event corresponds with the major climactic changes and low CO(2) levels of the late Miocene and/or early Pliocene. Subsequent bursts of diversification have proceeded in each ocean since this transition. An ecoevolutionary expansion to numerous and taxonomically diverse hosts by a select host-generalist symbiont followed by the onset of rapid diversification suggests a radical process through which coral-algal symbioses respond and persist through the vicissitudes of planetary climate change.

EFFECTS OF SOLAR ULTRAVIOLET RADIATION ON STREAM BENTHIC COMMUNITIES: AN INTERSITE COMPARISON

The effects of solar ultraviolet radiation (UVR), both mid-ultraviolet (UVB; 280–320 nm) and near-ultraviolet (UVA; 320–400 nm), on benthic algal and invertebrate communities were compared in three reaches of a British Columbia coastal stream that differed in the degree of shading by riparian canopy (a full canopy, a partial canopy, and no canopy). At each of the three sites benthic communities were exposed to three different radiation treatments: photosynthetically active radiation alone (PAR; 400–700 nm), PAR+UVA, and PAR+UVA+UVB. Relative to the site with no canopy, UVR was 88% and 66% lower, and PAR was 83% and 49% lower at sites with full and partial canopy, respectively. Late summer increases in UVR to the streambed caused by declines in water level and dissolved organic carbon (DOC) were also lower at sites with high canopy. Sites with less canopy shading had greater algal accrual, decreased biomass of total invertebrates, mayflies, and stoneflies, and reduced invertebrate community diversity compared to the heavily shaded reach of the stream. UVR produced taxon-specific community responses that varied across sites and increased with increasing UVR as summer progressed. At the full canopy site UVR had no impact, and the final (day 91) biomass and diversity of invertebrates was highest, and algal biomass lowest. Higher UVA radiation under reduced canopies inhibited algal accrual but had little effect on algal community composition. The biomass of several invertebrate taxa (e.g., Dicosmoecus spp., Limnephilidae) and community diversity were reduced by both UVA and UVB. Less sensitive taxa (e.g., Paraleptophlebia spp., Paraleptophlebidae) were inhibited only by the highest UVB levels in late summer when water transparency to UVR was greatest. Inhibition of grazers by UVR appeared to indirectly increase algal accrual, particularly at the partial canopy site. Our results indicate that riparian shading may moderate UVR effects on benthic communities, mainly through impacts on invertebrates with indirect effects on algae. By reducing UVR exposure of streambeds, riparian canopies may be important for ameliorating UVR effects on shallow lotic systems, especially during late-summer, low-flow periods when DOC concentrations are reduced.

Species distribution and habitat exploitation of fauna associated with kelp (Laminaria Hyperborea) along the Norwegian Coast

Fauna associated with the common kelp along the Norwegian coast, Laminaria hyperborea, was sampled at four sites covering 1000 km of coastline. Exploitation of the kelp habitat by the fauna, and the ways in which habitat size and seasonal variations affect the kelp fauna community were analysed. The study focused on mobile macrofauna, of which 238 species were found on 56 kelps sampled, with an average density of almost 8000 individuals per kelp. Amphipods and gastropods were the most diverse and abundant fauna groups. The species composition was different on the lamina, stipe (with epiphytic algae) and holdfast. A similar pattern of epiphyte- and holdfast-fauna composition was found for all regions. Lowest diversity and abundance were found on the lamina, and highest diversity in the holdfast. Highest abundance was found on the stipe in summer, but there were large variations between sites and seasons, from a few individuals to more than 80 000 animals per stipe. Neither seasonal changes nor variation in habitat volume affected the number of species significantly, but abundance was significantly related to season and habitat volume. These variations were most pronounced for stipe fauna. Laminaria hyperborea offers a heterogeneous habitat exploited by a diverse and abundant invertebrate community, its abundance depending on local and regional variations in kelp size.

Changing management in Scottish birch woodlands: a potential threat to local invertebrate biodiversity.

The silvicultural management of Scottish birch woodlands for timber production is replacing traditional low intensity management practices, such as domesticated livestock grazing. These new management practices involve thinning of existing woodlands to prescribed densities to maximize biomass and timber quality. Although presently infrequent, the wide scale adoption of this practice could affect invertebrate community diversity. The impact of these changes in management on Staphylinidae andCarabidae(Coleoptera) in 19 woodlands in Aberdeenshire, north-east Scotland was investigated. Grazing and logging practices were important determinants of beetle community structure. Woodland area had no effect on any measure of beetle community structure, although isolation did influence the abundance of one carabid species. Changes towards timber production forestry will influence the structure of invertebrate communities, although the scale at which this occurs will determine its effect.

Colonisation of kelp imitations by epiphyte and holdfast fauna; a study of mobility patterns

The kelp Laminaria hyperborea provides a habitat for a diverse invertebrate community. Invertebrate abundance is particularly high in the kelp holdfasts and associated with epiphytes on the stipes. We investigated colonisation patterns of this fauna on artificial substrata (holdfast and epiphyte mimics) exposed for short time periods in the kelp forest in two seasons, summer and late autumn. Within 7 days, 99 taxa common on natural kelp substratum colonised the artificial substrata in large numbers, demonstrating high mobility and indicating that there may be a rapid exchange of individuals and species among algae. Gastropods and amphipods were the most abundant colonisers. In summer, a specific “epiphyte fauna” could be distinguished from a “holdfast fauna”, and species associated with epiphytes were significantly more abundant on the artificial substrata. Colonisation was more rapid in summer than in late autumn, which may be related to animal population density. The high dispersal rate can facilitate the interaction with other communities and with higher trophic levels in the kelp-forest food web.

Diet of Sanderling in Buenos Aires Province, Argentina

Abstract The diet of the Sanderling (Calidris alba) was studied using 105 droppings, 34 pellets and direct observations of feeding behavior. This study was carried out during the non-reproductive seasons of 1996 to 2000 in Monte Hermoso, SW of Buenos Aires, Argentina. A total of eleven prey items were identified, with beetles (Coleoptera), Mussels (Brachydontes rodriguezi), clams (Corbula sp.), amphipods (Corophium sp.) and Diptera being the most frequent. The consumption of polychaetes, algae, ants and small fish was also recorded. Sanderlings followed foraging American Oystercatchers (Haematopus palliatus) and cleaned out the valves of mussels and clams (Mesodesma mactroides) left by them. Mussels and beetles were the most constant and dominant prey during the study period. The association of Sanderlings with sandy coasts with rocky patches or restingas is probably due to the rich and diverse invertebrate communities present in this kind of environment, which allow birds to change feeding techniques bet...

Invertebrates in ornithogenic soils on Ross Island, Antarctica

A habitat suitability model developed for soil biotic communities in the McMurdo Sound region, Antarctica predicts that soil moisture, organic carbon, and salinity exert control on the abundance and complexity of soil food chains. The model has been intensively tested in dry and carbon-poor soils of the Dry Valleys. To determine the influence of moisture and soil organic mater in wetter soils with high C content, invertebrates (nematodes, rotifers, and tardigrades) from soil samples collected in and near penguin rookeries on Ross Island (Cape Bird, Cape Crozier, and Cape Royds) were examined. Invertebrates were present in less than 50% of all collected soil samples. Although four nematode species were identified (Eudorylaimus antarcticus, Panagrolaimus davidi, Plectus antarcticus, Scottnema lindsayae), only populations of Panagrolaimus davidi were observed in soils collected from within penguin rookeries. Abundances of Panagrolaimus davidi and rotifers differed among rookeries, and year of sampling had a significant effect only on the populations of Panagrolaimus davidi. There were no temporal differences in soil moisture and soil chlorophyll a concentrations within each rookery or across rookeries. No invertebrates were correlated with soil moisture or chlorophyll a at the time of collection. Counter to our expectations, higher nutrient, organic matter, and moisture levels did not result in more abundant and diverse invertebrate communities in the rookery soils. It appears that excessive accumulations of nutrients, creating high soil salinity, may limit soil invertebrate presence within active rookeries.

Depth-area-volume and hydroperiod relationships of ephemeral (vernal) forest pools in southern New England

Ephemeral or ''vernal'' pools occur commonly throughout the forests of the northeastern United States and adjacent eastern Canada. These pools are critical breeding habitat for a number of amphibian species and support a diverse invertebrate community. The hydroperiod or duration of surface water of vernal pools affects faunal composition and reproduction. We conducted bathymetric surveys of 34 vernal pools located in central Massachusetts in early spring when the pools were at maximum extent after receiving snowmelt runoff. With these data, we estimated maximum pool depths, surface areas, perimeters, volumes, and basin profile coefficients. We calculated relative hydroperiod indices for the pools based on the presence or absence of surface water during periodic pool visits over the three-year study. The ranges of estimated pool morphological parameters were 0.11-0.94 m for maximum depth, 68-2941 m 2 for maximum surface area, 6-506 m 3 for maximum volume, and 30-388 m for maximum perimeter. Basin profile coefficients ranged between 0.60 (convex) and 2.24 (concave), with a median value of 1.02 (straight slope). Maximum pool depth was positively correlated with area and perimeter, but the correlations were only moderately strong, and there were many shallow pools with large surface areas. Correlations between basin profile coefficients and other morphological parameters were weak or non-significant. Maximum pool volume was proportional to the product of area and depth, but the proportionality constant was dependent on the basin profile coefficient. Relative hydroperiod was weakly correlated with pool morphometry; the strongest rela- tionship was found between hydroperiod and maximum pool volume. In general terms, pools with a maxi- mum depth greater than 0.5 m, a maximum surface area larger than 1000 m 2 , or a maximum volume greater than 100 m 3 had surface water more than 80% of the times they were visited. In contrast, shallower pools, smaller pools, or pools with lesser volumes had varying hydroperiods. The weak relationships between pool morphometry and hydroperiod indicate that other factors, including temporal patterns of precipitation and evapotranspiration and ground-water exchange may have significant influence on vernal pool hydrology and hydroperiod.

Macroinvertebrates As Bioindicators of Water Pollution in Streams Draining Dairy Farming Catchments

Runoff from intensive dairy farming systems can impair the quality of catchment waters, with potential ecological and human health implications. A water quality study was carried out in three streams in a predominantly dairy farming region, with the aim of assessing the effects of diffused- and point-sourced inputs on a number of water quality parameters and benthic macroinvertebrates. the results showed significant increases in streamwater biochemical oxygen demand (BOD), ammonium-nitrogen (NH4-N) and molybdate reactive phosphorus (MRP) concentrations between the farm reaches. These changes in water quality appeared to be due largely to the point-sourced inputs from farmyards, and had a significant effect on the ability of the water to support a healthy and diverse community of invertebrates. the results also showed that concentrations of dissolved oxygen (DO) and ammonium in streamwater were the two most important parameters studied that were inversely related to the invertebrate scores.

Plasmid transfer between strains of Pseudomonas putida, and their survival, within a pilot scale percolating-filter sewage treatment system

The ability of non-indigenous bacteria to survive and conjugate within a fully functioning pilot-scale percolating filter bed, with a substantial biofilm and a diverse invertebrate community, was investigated. Pseudomonas putida UWC8, harbouring the conjugative plasmid pQKH6, isolated from river epilithon, and P. putida UWC9 were introduced and survived in a culturable state for up to 145 days. During this time plasmid transfer, with transfer frequencies of up to 6.54 × 10 −5 cfu per recipient, could be detected. The macro-invertebrate community was also investigated. The invertebrate grazers had no detectable effect upon the densities of the introduced bacteria.

Empirical relationships between diversity of invertebrate communities and altitude in rivers: Application to biomonitoring

The relationships between the diversity of invertebrate communities and the altitude of sampling sites were analysed in 438 benthic samples, collected between 1982 and 1991, in 56 rivers of western Switzerland. Diversity, estimated from total number of taxa (genus or family) and from number of taxa intolerant of pollution, was positively correlated with increasing altitude. In contrast, density of human population and the level of organic pollution were negatively correlated with increasing altitude. Therefore, the upstream increase of invertebrate diversity was attributed to the decrease of human population which is the main source of organic pollution. In this study, altitude was used, instead of organic pollution, to predict diversity. Empirical relationships between diversity and altitude were applied to surveys of water quality to describe the general altitudinal pattern characteristic for each region and to single out anomalous sites and rivers. In addition, changes in the altitudinal patterns of diversity can be used to monitor the recovery of rivers from pollution.

Water trapping by seagrasses occupying bank habitats in Florida Bay

Seagrasses, largely Thalassia testudinum, occupy habitats atop shallow ( < 0·5 m deep) carbonate mudbanks adjoining basins up to 3 m deep in Florida Bay. We quantified the phenomenon of water trapping whereby, during low tides, the seagrass meadow matrix retains a thin ( < 20 cm) layer of water high on the bank top despite water levels in the adjoining basins being some 25–70 cm lower. The matrix slows water flow off the banks such that changes in the rate at which water recedes through time approximates a sigmoid function of water level. A meadow with a large seagrass standing crop (59·0 g dry mass m −2) held a 17·4-cm layer of water atop the bank, while a meadow of lesser standing crop (less biomass per area, 13·0 g dry mass m −2) that may have been facilitated by a topographical berm held just 3·3 cm of water. Similarly, on the bank slope the higher standing crop meadow held 10·4 cm of water while the bank slope meadow at the site with lesser standing crop held only 1·6 cm of water. Water trapping by seagrass can keep water on the banks for up to 8 h during low tides, preventing desiccation of the bank, and thereby providing permanent habitat for a diverse community of epibenthic fishes and invertebrates. The water trapping phenomenon presumably enhances overall prey abundance and diversity, and regulates the temporal patterns of prey exposure to different types of predation risk, e.g. to wading birds vs. predatory fishes.

Nannoplankton productivity fluctuations and rhythmically-bedded pelagic carbonates of the greenhorn limestone (upper cretaceous)

Comparison of calcareous nannofossil assemblages from rhythmically-interbedded calcareous shales and adjacent bioturbated chalks of the Greenhorn Limestone (Cenomanian-Turonian) of the Western Interior Basin indicate significant changes in phytoplankton paleocommunity structure between lithotypes. Significantly higher Shannon diversity and evenness values in the chalk assemblages indicate more stable surface water conditions with lower fertility. Three taxa indicative of high surface water fertility are significantly more abundant in marlstone assemblages which suggests that calcareous shale/marlstone deposition corresponded with fluctuating surface water conditions with relatively high fertility. The higher surface fertility and concomitant production of organic matter resulted in sediment anoxia during marlstone deposition, leading to high rates of organic carbon storage. Reduced phytoplankton production during chalk deposition allowed oxygenation of the sea floor and establishment of diverse benthic invertebrate communities.

Marine invertebrates in an algal succession. III. Mechanisms linking habitat complexity with diversity

A diverse community of marine invertebrates is associated with suceessional algal mats in an intertidal boulder field in southern California. Species richness and abundance of invertebrates increased from early to middle suceessional stages, then remained similar into the later stage. These changes are paralleled by those in the physical structure (biomass and surface area) of the algae. Increased complexity of the algal physical structure probably influenced the associated invertebrate community through several mechanisms. (1) It decreased mortality caused by predation from fish and crabs. (2) It reduced the severity of physical stresses, primarily wave shock. (3) It increased the accumulation of those individuals and species transported passively by wave action. (4) In mobile species, selection of algal substrates was largely based on physical aspects of algal structure. While no species tested appeared to select particular algal species. all actively chose algal clumps of high biomass. All four mechanisms result in the accumulation of greater numbers of individuals in algal mats with higher biomass and surface area. Because a larger sample of the available pool of individuals is collected, more species are found in a given area of algal mat when the structure is more complex. The suceessional patterns of change in species richness of the invertebrate community seem to result from this sampling phenomenon. Laboratory experiments and correlations in abundance between pairs of species gave no evidence of any competitive interactions. Any apparent “structure” in this assemblage seems to be the result of the summation of individual responses to changing algal physical structure during succession.

Ecology of the tube-building polychaete Diopatra leuckarti Kinberg, 1865 (Onuphidae) in Hawaii: community structure, and sediment stabilizing properties*

Large numbers of the tube-building polychaete Diopatra leuckarti Kinberg form extensive mounds of sand on a Hawaiian reef-fiat, providing a stable environment with plentiful resources to support a diverse invertebrate community. The vertically oriented tubes reach densities of 21 800 m-2 and the projecting tubes trap drift algae and sediments which are sources of food and tube-building materials for the associated community. There are 22 polychaete species, six crustacean species and eight of other taxa represented, with Leptochelia dubia (tanaid) and Capitella capitala (capitellid) as the dominant organisms, reaching densities of 32 800 m-2 and 11600 m-2, respectively. Both species form fine mud tubes on the sediment surface among the Diopatra tubes. Other numerically abundant taxa are the deposit feeders comprising orbiniid, capitellid and cirratulid polychaetes, small crustaceans and a holothurian. Crustaceans, fishes and polychaetes are the primary predators. Both low salinities (15–26%, at low tides) due to ground water seepage and fine sediments are probably major factors affecting the species composition of the Diopatra mounds. They also act as a buffer between the reef-flat and the beach, serving to reduce beach erosion.

Review of the Benthos of the Strait of Georgia and Contiguous Fjords

The distribution of benthic communities in the Strait of Georgia is partially determined by the relative areas of various sediment types, their depths, and characteristics of overlying water. Rocky shores, which account for 88% of the shoreline length, have been fairly closely examined and communities have been described in the context of worldwide zonation patterns. The ecology of macrofauna and meiofauna of unconsolidated sediments at several estuaries (Nanaimo, Fraser, Squamish) has been documented. In eelgrass beds, very diverse invertebrate communities are found, whereas in brackish marshes closer to river mouths the ecosystem is characterized by a few very abundant species. To date, between 325 and 350 macroalgae species have been recorded from the shallow subtidal habitats of the Strait. In an intensive study at Bath Island, 10 algal communities were defined, each with an associated faunal group. The deep subtidal habitats are extensive: 71% of the surface area of the bottom of the Strait is between 50 and 300 m. These habitats are dominated by burrowing macrofauna such as holothurians, bivalves, and the heart urchin, Brisaster latifrons. The fauna of the rocky walls of fjords connecting with the Strait are characterized by cup corals, brachiopods, and sponges. Even though subject to low and fluctuating dissolved oxygen levels, a diverse fauna of epilithic organisms has been found in Saanich Inlet. Agglomeration, flocculation, and zooplankton pelletization are important mechanisms for transport of phytodetrital food for deep subtidal benthos. Provision of organic material from nearshore and riverine production sites is very important because of the extensive shoreline around the Strait. Juvenile salmonids, especially chinook (Oncorhynchus tshawytscha) and chum (O. keta), are strongly shoreline oriented and feed on epibenthic crustaceans and insects on foreshores. The deeper subtidal habitats in the Strait apparently do not support productive bottom fish communities. Although the major benthic assemblages have been described and standing crops have been estimated, there are very few data on the dynamics of benthic communities, secondary production of zoobenthos, benthic–pelagic coupling, or the quantitative relationships between oceanographic variables and benthic production.

The Role of Predation in Causing Major Changes in the Limnology of a Hyper‐Eutrophic Lake

AbstractAn experiment was carried out by separation of a shallow man‐made lake into two basins with an earth dam. Unintended leaks allowed extremely fertile river water to feed both basins so that nutrients were unlikely ever to have been limiting to phytoplankton populations. The two basins had greatly differing fish populations. In the basin in which these were low, a chain of events took place in which zooplankton grazing reduced phytoplankton growth sufficiently to allow establishment of aquatic macrophyte populations and an associated diverse benthic invertebrate community. In the basin to which fish had free access from the river, phytoplankton populations remained high, and no aquatic macrophyte community developed. The implications of these observations for shallow lake management are considered.

Effects of eroding oil sand and periodic flooding on benthic macroinvertebrate communities in a brown-water stream in Northeastern Alberta, Canada

The portion of the Steepbank River which cuts through the Athabasca oil sands deposit supported a less diverse benthic invertebrate community than did upstream areas. The variety and relative abundance of Plecoptera and Trichoptera were consistently lower in the area of oil sand exposure. As a substrate for benthic invertebrates, oil sand appears to be analogous to bedrock, supporting about 60% as many animals per unit area as adjacent rubble substrates. Burrowing and negatively phototropic organisms were significantly less abundant on oil sand than on rubble. When high discharge of the Athabasca River flooded a riffle to form a pool near the mouth of the Steepbank, rheophilic forms, such as Baetis and Simulium, were largely eliminated from the riffle and benthic standing stocks were reduced by about 50%. The invertebrate community recovered quickly after riffle conditions returned.

The Effect of Stable Dissolved‐Oxygen Stress on Marine Benthic Invertebrate Community Diversity

AbstractThe Fosa de Cariaco off the coast of Venezuela is an anoxic basin which is subject to small seasonal fluctuations in the depth of the anoxic water. Samples taken in the interface region (between oxic and anoxic waters) contained from 13 to 37 species represented by 117 to 380 individuals. Species‐diversity, based on H′(s), was greater than that previously reported for samples from oxygen minimum regions. It is suggested that the relatively stable low dissolvedoxygen concentrations allow the development of diverse assemblages.