High Diversity Of Invertebrates Research Articles

Remotely characterizing photosynthetic biocrust in snowpack-fed microhabitats of Taylor Valley, Antarctica

Microbial communities are the primary drivers of carbon cycling in the McMurdo Dry Valleys of Antarctica. Dense microbial mats, consisting mainly of photosynthetic cyanobacteria, occupy aquatic areas associated with streams and lakes. Other microbial communities also occur at lower densities as patchy surface biological soil crusts (hereafter, biocrusts) across the terrestrial landscape. Multispectral satellite data have been used to model microbial mat abundance in high-density areas like stream and lake margins, but no previous studies have investigated the lower detection limits of biocrusts. Here, we describe remote sensing and field-based survey and sampling approaches to study the detectability and distribution of biocrusts in the McMurdo Dry Valleys. Using a combination of multi- and hyperspectral tools and spectral linear unmixing, we modeled the abundances of biocrust in eastern Taylor Valley. Our spectral approaches can detect low masses of biocrust material in laboratory microcosms down to biocrust concentrations of 1% by mass. These techniques also distinguish the spectra of biocrust from both surface rock and mineral signatures from orbit. We found that biocrusts are present throughout the soils of eastern Taylor Valley and are associated with diverse underlying soil communities. The densest biocrust communities identified in this study had total organic carbon 5x greater than the content of typical arid soils. The most productive biocrusts were located downslope of melting snowpacks in unique soil ecosystems that are distinct from the surrounding arid landscape. There are similarities between the snowpack and stream sediment communities (high diversity of soil invertebrates) as well as their ecosystem properties (e.g., persistence of liquid water, high transfer of available nutrients, lower salinity from flushing) compared to the typical arid terrestrial ecosystem of the dry valleys. Our approach extends the capability of orbital remote sensing of photosynthetic communities out of the aquatic margins and into the drier soils which comprise most of this landscape. This interdisciplinary work is critical for measuring and monitoring terrestrial carbon stocks and predicting future ecosystem dynamics in this currently water-limited but increasingly dynamic Antarctic landscape, which is particularly climate-sensitive and difficult to access.

New insight into the macroinvertebrates of the Rawka River Nature Reserve (central Poland)

This paper presents the results of a preliminary survey on macroinvertebrate communities of a pristine lowland river Rawka in central Poland. The whole river is protected by a nature reserve but its invertebrates haven’t yet been investigated extensively. This research has three main objectives: 1) to recognise preliminarily Rawka’s macrofauna, 2) to determine the dissimilarity pattern between macroinvertebrates from the riverbed and the local oxbow, 3) to compare the invertebrate assemblages occurring in different habitats. The material was collected at three riverbed sampling points and one oxbow study site. It was found that the oxbow of Rawka River has different aquatic invertebrate communities than the riverbed. Conducted preliminary studies indicate that Rawka and its oxbow reveal high invertebrate diversity that is still vastly underestimated. Seventy-seven invertebrate taxa were collected and twenty-seven of them are first-recorded for Rawka River. Some rare and protected species have been found in the river, e.g. Ophiogomphus cecilia − a dragonfly which remains under strict species protection in Poland. The composition of aquatic invertebrates indicates that water quality of Rawka at the investigated section is good, but this needs to be confirmed with more extensive studies.

Rhinodrilus priscilae and Andiorrhinus (Amazonidrilus) caxiuana (Crassiclitellata, Rcrilidae) two new species from Caxiuanã National Forest

The amazon forest is the habitat of a high species diversity of invertebrates and unfortunately the real richness had been underestimated. Earthworms' inventories had been poor because difficult to describe new species. This study adds new records to eastern amazon of two new species belong Rhinodrilus and Andiorrhinus genera. R. priscilae n. sp. is another rare specimen of the genre having two pair of prostatoid glands. A. (Amazonidrilus) caxiuana differ of other species in size, the intestinal origin is in XXVIII and also has only one glandular mass associated to spermatheca.

A Multi-Community Approach in Biodiversity Assessment of a Peat Bog in the Southern Carpathians (Romania) and Implications for Conservation.

Although natural peatlands have been recognized as an important type of wetlands because they support high biodiversity and provide important ecosystem services, the value of peatlands both in biodiversity research and conservation is still largely underestimated. Our study characterizes the biodiversity and conservation value of Peşteana peat bog, an upland mesotrophic peat bog, located in the Southern Carpathians, Romania. More specifically, we: (1) characterized the invertebrate (i.e., top soil, surface litter, and plant-dwelling) and plant communities along a humidity gradient in Peşteana peat bog and nearby habitats (i.e., treeline, ecotone, lowland and highland meadow, and forest), (2) assessed the main environmental factors driving the invertebrate community diversity and composition, and (3) determined the relationship between invertebrate community diversity and vegetation, focusing on the top soil invertebrates. Our study revealed a high diversity of invertebrates spanning over 43 taxonomic groups and a high number of plant indicator species, emphasizing the role of natural peatlands in preserving diverse communities in a small area. The results showed that the composition of top soil invertebrate community was determined by depth of organic layer, vegetation cover, and soil compaction. We found that the diversity of top soil invertebrate community was strongly influenced by habitat type and soil attributes and weakly by vegetation. Overall, the invertebrate and plant communities showed different responses to habitat conditions along the humidity gradient. This highlights the importance of using a multi-community approach to support the design of effective conservation and management actions beneficial for a wide range of taxa.

Trace elements in relation to trophic ecology of long-distance migratory shorebirds and seabirds in West Africa

Shorebirds and seabirds are abundant predators in coastal habitats worldwide, relying upon a high diversity of benthic invertebrates and fish, respectively. While occupying different trophic guilds, they are differently exposed to element contamination entering the coastal food web. Therefore, these birds have been used as bioindicators of environmental contamination in marine ecosystems. We analysed the concentration of trace elements in blood samples of 16 shorebird and seabird migratory species in a major non-breeding site, the Bijagós Archipelago, in regard to their trophic ecology. Overall, our study shows low exposure of this bird community to toxic elements, except for Hg. Most species presented Hg burdens within the moderate toxicity threshold, but one species (Dunlin) presented values at a potential high Hg toxicity risk. We found a positive relationship between Se and Ni concentrations and δ15N values (a proxy for trophic level). In addition, a positive relationship was found between δ13C (a proxy for habitat characteristics) and Hg, Fe, Cu and Mn, while the opposite pattern was recorded for As. Differences were also shown for several trace elements between the two studied trophic guilds: concentrations of As, Pb and Se were higher in pelagic fish consumers (seabirds), whereas Cr, Fe and Sr burdens were higher in benthic invertebrate consumers (shorebirds). Although previous studies in the same site revealed very high concentrations of Cd and Pb in some of the prey species of shorebirds and seabirds (bivalves and fishes), values found in birds for these two elements suggest no toxicological risk. Thus, exposure to toxic elements is not currently a threat to coastal bird populations, namely those facing apparent local declines in Guinea-Bissau, one of the most important non-breeding quarters for of West Africa. Still, Hg burdens were high in some species, deserving further monitoring.

AUMENTO DA MESOFAUNA EDÁFICA RESULTANTE DO ESTABELECIMENTO DE ÁRVORES E EXCLUSÃO DE ANIMAIS EM UM SÍTIO DEGRADADO DE CAATINGA

ABSTRACT Environmental degradation impacts negatively the diversity and quantity of invertebrates living in the soil, mainly in semiarid regions. Generally, a high diversity of invertebrates indicates good biofunctionality and sustainable use of the soil. We evaluated the effects of 14 years of grazing deferment and the presence of the native trees Mimosa tenuiflora and Cnidoscolus quercifolius on the soil mesofauna of a degraded Caatinga area, according to the χ 2 test, applied to assess the abundance of these microorganisms. The grazing deferment alone more than tripled the soil mesofauna. The abundance of the mesofauna under M. tenuiflora canopies increased by a factor of 3.17 and 3.41 in grazed and ungrazed areas, respectively, and under C. quercifolius canopies increased by a factor of 22.6 in the ungrazed area. The effect of M. tenuiflora in the grazed area was similar to 14 years of grazing deferment. The quantity of mesofauna under C. quercifolius canopies after 14 years of grazing deferment was 6.6-fold higher than that under M. tenuiflora canopies, under similar conditions. The grazing deferment and trees, especially C. quercifolius, increased the soil mesofauna; however, full recovery of such organisms in degraded Caatinga areas may need more than 14 years. Considering the current scenario of increasing environmental degradation, our findings regarding the relationships between soil mesofauna, grazing deferment and native trees are important to devise strategies and procedures for the recovery of degraded areas in the Caatinga biome.

Pilbarana, a new subterranean amphipod genus (Hadzioidea: Eriopisidae) of environmental assessment importance from the Pilbara, Western Australia

The Pilbara and nearby regions in north-western Western Australia have an exceptionally high diversity of short-range endemic invertebrates inhabiting threatened groundwater-dependent habitats. Amphipod crustaceans, in particular, are dominant in these communities, but are poorly understood taxonomically, with many undescribed species. Recent molecular phylogenetic analyses of Pilbara eriopisid amphipods have, nonetheless, uncovered a previously unknown biodiversity. In this study, we formally establish a new genus, Pilbarana Stringer & King gen. nov., and describe two new species, P. grandis Stringer & King sp. nov. from Cane River Conservation Park and P. lowryi Stringer & King sp. nov. from the Fortescue River Basin near the Hamersley Range, using a combination of molecular and morphological data. The new genus is similar morphologically to the two additional Western Australian eriopisid genera, Nedsia Barnard & Williams, 1995 and Norcapensis Bradbury & Williams, 1997, but represents a genetically divergent, reciprocally monophyletic lineage, which can be differentiated by its vermiform body shape, the presence of an antennal sinus, and by the length and form of the antennae and uropods. This research signifies an important contribution to knowledge of Pilbara subterranean communities and has critical implications for future environmental impact assessments and conservation management.

New Insights into a Mediterranean Sea Benthic Habitat: High Diversity of Epiphytic Bryozoan Assemblages on Phyllophora crispa (Rhodophyta) Mats

With its geographically isolated location and geological history, the Mediterranean Sea harbors well-known biodiversity hotspots, such as Posidonia oceanica seagrass meadows. Recently, long-living mats formed by the fleshy red alga Phyllophora crispa have been described to be associated with a high diversity of sessile invertebrates in the Tyrrhenian Sea. One of the key taxa among these sessile invertebrates are bryozoans: their abundance, diversity, and spatial distribution in P. crispa mats represent a gap in scientific knowledge. Thus, we conducted a pilot study on bryozoan assemblages associated with P. crispa mats around Giglio Island (Tuscan Archipelago, Italy) in 2018, followed by a comparative study on four sites distributed around the island in the subsequent year, 2019. We compared these findings to bryozoan abundance and diversity on P. oceanica shoots and leaves during the second expedition. The findings revealed more than 46 families, with a significantly higher number of taxa identified in P. crispa mats (33) than in P. oceanica meadows (29). The Shannon diversity index was similar between P. crispa and P. oceanica shoots, while Pielou’s evenness index was lower in P. crispa mats. The most abundant families reported across all habitats were Crisiidae, Aetidae, and Lichenoporidae; but the most abundant family on P. crispa was Chlidoniidae (Chlidonia pyriformis). The assemblages associated with P. crispa differed among sites, with higher abundances but lower diversity on the exposed southernmost site. The total bryozoan abundance was significantly higher on P. crispa (average 2.83 × 106 ± 1.99 × 106 colonies per m2 seafloor) compared to P. oceanica meadows (average 0.54 × 106 ± 0.34 × 106 colonies per m2 seafloor). Our results show a high diversity of bryozoans on P. crispa thalli compared to P. oceanica meadows, which was consistent throughout the study. These findings confirm the value of the red alga-generated habitat for associated bryozoans and may have implications for future biodiversity assessments and conservation measures.

The Importance of Surface Orientation in Biodiversity Monitoring Protocols: The Case of Patagonian Rocky Reefs

Temperate rocky reefs in Atlantic Patagonia are productive areas that support a high diversity of invertebrates, algae, and fishes. Complex surface structures on rocky reefs offer a range of microhabitats, which in turn, lead to a broad variety of co-existing species. Despite their ecological importance and the ecosystem services they provide, Patagonian rocky reef habitats have received limited attention. Until now studies have not discerned nor consequently described the assemblages found on each of the different surface orientations, namely horizontal, vertical, overhang and cavefloor. During this study we developed a protocol for sampling different surface orientations on subtidal rocky reefs using georeferenced high-resolution photoquadrats. We described and compared the epibenthic assemblage of surface orientations on 7 rocky reefs within 1–25 m depth in a northern Patagonia gulf. A total of 70 taxa were identified (12 macroalgae, 44 invertebrates, 10 tunicates, and 4 fishes), which doubles the number of species previously reported for the area. Each surface orientation presented a different assemblage structure while species richness was higher on vertical surfaces. The overhang surfaces had the most distinct assemblage conformed by cnidarians, tunicates, sponges and the absence of algae. The average overall species richness increased with depth due to the increase of sponge and tunicate species. Our results highlight the need of including several surface orientations in rocky reef biodiversity monitoring. This study offers a protocol for large-scale programs aimed at monitoring changes in biodiversity, which is broadly accessible and will provide accurate information. With robust yet simple, non-destructive and relatively low-cost practices this protocol can adequately assess changes in marine habitats, which provide important ecosystem services.

Maintaining mechanisms of riparian invertebrate biodiversity: A review

Riparian zones, the critical ecological interfaces between terrestrial and aquatic ecosystems, are species rich habitats. However, riparian zones are seriously threatened by human activities in the world. Riparian invertebrates represent a large proportion of riparian biodiversity, perform various ecological functions, and provide an essential link between aquatic and terrestrial ecosystems. Although many studies have investigated the riparian invertebrate communities, there is lacking a comprehensive summary of maintaining mechanisms underlying riparian invertebrate diversity. This review discussed seven characteristics of riparian zones that might support high riparian invertebrate diversity: flood and drought, nutrient, microhabitat diversity, riparian vegetation, microclimate gradients, food resources and river spatial gradients. Further, we summarized the maintaining mechanisms of riparian invertebrate diversity. Disturbances of periodic flood and drought trigger the reproduction and migration of invertebrates, increase the turnover of invertebrate communities, and create suitable conditions for riparian invertebrates. Adequate nutrients support a high invertebrate diversity by increasing primary productivity of riparian habitats. Elevated microhabitat diversity provides a variety of niche space for specialist riparian invertebrates. Strong microclimate gradients provide complex and diverse habitats and thus facilitate the coexistence of aquatic and terrestrial invertebrates in riparian zones. Cross-ecosystem resource subsidies increase food availability and contribute unique food sources to riparian invertebrates. The differentiation of these factors along river longitudinal and lateral gradients provides conditions for the diversification of riparian invertebrates at a larger scale. Understanding the maintaining mechanisms of riparian invertebrate diversity is important for conservation of riparian biodiversity and integrated management of river ecosystems.

Ecological Role of an Offshore Industry Artificial Structure

Decommissioning of oil and gas infrastructure in all major basins globally has focused attention on its importance as hard substratum on continental shelf and slope habitats. Observational studies are needed to improve understanding of faunal assemblages supported by offshore infrastructure and better predict the effect of removal. Here we present results from visual inspection and physical sampling of a small oil and gas industry structure decommissioned from an oil field in the North East Atlantic. This is supported by observations of similar structures nearby and by photographs of the surrounding seabed from environmental baseline surveys. The structure supported a reasonably high biomass and diversity of invertebrates (>10 kg and > 39 macrofaunal and 17 megafaunal species) and fishes (>20 kg biomass and > 4 species). The invertebrate megafaunal species present on the structure were a sub-set of the hard substratum fauna observed on surrounding seabed. Porifera were absent from the structure. Biological succession in the first two years occurred as follows. Sparse colonies of the hydroid Obelia sp. stet were early colonisers then subsequent development of thick hydroid turf (Obelia sp. stet. and Halecium sp. stet.) supported a diverse invertebrate assemblage (2654 individuals kg wet mass-1) dominated by saddle oysters (Pododesmus squama (Gmelin, 1791) and Heteranomia sp. stet.)) and scale worms (Hormothoe spp.). Percentage cover of hydroid turf varied significantly over the structure, with most growth on sections exposed to strongest currents. Commercially important fish species present around the structure included Gadus morhua (Atlantic cod), Pollachius virens (saithe) and Lophius piscatorius (monkfish). Studies of artificial structures such as this provide much needed data to understand their role in the ecology of seafloor habitats and inform environmental decision making on all stages of industry from exploration to decommissioning. We show that the ecological role of the decommissioned three-dimensional structures was to enhance the biomass of a sub-set of epifaunal invertebrates found in the area. This supported diverse associated macrofaunal organisms, providing a food source for motile invertebrates and fishes in an area where background hard substratum can be lost through the impacts of drilling.

Food or furniture: Separating trophic and non‐trophic effects of Spanish moss to explain its high invertebrate diversity

AbstractFoundation species are typically suggested to enhance community diversity non‐trophically by increasing habitat structure and mitigating physical stress, while their trophic role is considered of minor importance. Yet, there is little experimental evidence on the relative importance of trophic and non‐trophic effects and the interaction with patch size. Here, we transplanted different festoon sizes of living Tillandsia usneoides (Spanish moss) and structural mimics assessing the trophic and non‐trophic roles of this habitat‐forming epiphyte in mediating the invertebrate community. Compared to bare branches, mimics enhanced species and feeding guild richness and abundances, but living festoons even more so, demonstrating that trophic and non‐trophic effects jointly stimulated the community. Specifically, our results show that, independent of patch size, 40% of the total species richness and 46% of total guild richness increase could be contributed to habitat structure alone, while Spanish moss trophically stimulated these metrics by another 60% and 54%. As detritivores were particularly enhanced in living festoons, our findings suggest that trophic stimulation occurred primarily through the provisioning of Spanish moss detritus. Our results highlight that foundation species can facilitate their associated communities through both trophic and non‐trophic pathways, calling for studies addressing their indirect trophic role via the brown food web.

Working to the conservation and good use of the Devonian palaeontological heritage in Floresta, Boyacá (Colombia): a review of teaching case studies to engage students and the community

The Floresta Massif, located in the Eastern Cordillera of Colombia, has a diverse and precious natural heritage. It is one of the areas that contains an exceptional palaeontological heritage of the Middle Devonian not only of Colombia, but also of South America. This heritage is represented by fossil specimens of marine fauna and terrestrial flora (correlated with North America and Europe) of the Floresta and Cuche Formations, respectively. Since 2004, actions made by several academic and research institutions, community and local government have introduced schoolchildren, teenagers and University students to art and science, and have promoted the conservation of palaeontological heritage as an essential, vibrant and relevant discipline. The high diversity of invertebrates, fishes and terrestrial plant fossils unearthed has promoted teaching and outreach projects, the creation of a small Museum of Palaeontology in the Floresta municipality, and the aim of developing a geotouristic ring road in the Floresta municipality and towns surrounding the Floresta massif. These initiatives are a lively example of conservation and good use of the palaeontological heritage of Floresta.

Urban rain-fed lakes: macro-invertebrate assemblages associated with Egeria najas as indicators of biological integrity in wetlands of Corrientes Province (Argentina)

In northeast Corrientes Province, there are more than 50,000 semi-rounded shallow rain-fed lakes. Several lakes have been disturbed mainly because urbanization causes eutrophication due to the illegal discharge of wastewater. We compared 22 metrics based on the structural attributes of macro-invertebrates associated with Egeria najas across seasons between five lakes with different human disturbance levels. Sixty-six samples of E. najas and associated invertebrates were collected seasonally using a net with an area of 962 cm2. A total of 17,737 macro-invertebrates of eight major groups, 35 families and 30 genera were recorded. The total macro-invertebrate abundance (number of individuals per plant dry weigh) and the family richness were significantly higher in less disturbed lakes than those under human disturbance, but the differences between seasons were not significant. Non-metric multidimensional scaling analysis differentiated the macro-invertebrate abundances between the more and less disturbed lakes; instead, the diversity indices were not useful for measuring the changes in the studied lakes. Besides, total number of taxa, number of EOT (Ephemeroptera, Odonata, Trichoptera) taxa, abundance and proportion of Trichoptera and abundance of Chironomidae reflected significant differences between the more and less disturbed lakes. Our results suggest that seven invertebrate metrics respond to urbanization, and they could be used to assess biological integrity of the studied lakes in complement of chemical monitoring of water quality. Management efforts should focus on the maintenance of macrophyte stands that provide high invertebrate diversity, which serve as food for a wide variety of fish.

Boreal Sand Hills are Areas of High Diversity for Boreal Ants (Hymenoptera: Formicidae)

The boreal forest in Canada comprises a wide variety of ecosystems, including stabilized (overgrown) sand dunes, often referred to as sand hills. Globally, sandy soils are known for supporting a high diversity of invertebrates, including ants, but little is known for boreal systems. We used pitfall trap sampling in sand hill, aspen parkland and peatland ecosystems to compare their ant diversity and test the prediction that areas with sandy soils have higher invertebrate diversity compared to more mesic/organic soils. Overall, sand hills had ~45% more ant species compared to other sampled ecosystems from Alberta. Similar to other studies, local canopy cover within sand hills was found to be inversely related to ant species richness and diversity. Although sand hills are rare across the region, they are high biodiversity areas for ants, with the sand hills of north-central Alberta having higher species richness of ants compared to other studied areas in Canada.

Middle Miocene shark teeth from the southern margin of the Pannonian basin system (Serbia, Central Paratethys)

This paper describes Middle Miocene (Badenian) shark teeth from Serbia and discusses their geographical distribution at other localities of the Central Paratethys. The shark teeth originate from Visnjica (near Belgrade), from Visnjica Clay, or the ?Pleurotoma Clay?. The variety of sharks is very low, but according to these fossils Visnjica is the richest among serbian localities. The sharks teeth reported in the paper belong to the following taxa: Otodus (Megaselachus) megalodon (AgAssiz, 1835), Hemipristis serra AgAssiz, 1835 and Odontaspididae indet. The high diversity of invertebrates (molluscs, echinoids, corals etc.) and other coeval fossil assemblages indicate a warm period (the Middle Miocene Climatic Optimum), which preceded the Middle Miocene Climatic Transition.

Differences in diversity and habitat use of avifauna in distinct mangrove areas in São Sebastião, São Paulo, Brazil

Mangroves are an important ecosystem for many bird species for breeding, roosting and feeding, but habitat use depends on the area and vegetation structure. Avifaunal diversity studies are essential to establish baseline knowledge, identify impacts on communities, and for the effective management of ecosystems, especially in coastal areas under intense anthropogenic pressure. In this study, we: 1) characterized the mangrove vegetation structure on a former landfill (Ferry's site) from the expansion of São Sebastião Port, on the southeast coast of Brazil, 2) compared bird richness, abundance, and seasonal diversity of waterbirds and terrestrial birds at Ferry's site, with four sites located on natural land at Araçá Bay, a small semi-enclosed coastal bay, and 3) analyzed birds' habitat use. Ferry's site and Araçá Bay both border the port in the São Sebastião municipality. Overall, 52 bird species were detected in Ferry's site and 78 species in Araçá Bay. The waterbird community showed a higher average richness, abundance, and diversity in Ferry's site (A1) than in the Araçá sites (A2-A5). There were significant differences in these variables among sites, but not among seasons. For terrestrial birds, average richness and diversity were higher at Ferry's site, but average abundance was higher at Araçá Bay. These differences may be explained by habitat heterogeneity in the areas, however no pattern in these variables was found among A2-A5, because A5 has less human traffic and has more edge vegetation, which attracts birds. Ferry's site was used mainly for roosting throughout the year and as a breeding site for four heron species in summer, whereas Araçá Bay was used mainly as a foraging ground for waterbirds. Differences in habitat use were probably due to the higher density and maximum height of mangrove vegetation at Ferry's site, even though mangroves of Araçá Bay had a greater structural development. Furthermore, Araçá Bay has a large tidal plain, with high invertebrate diversity, which could explain why waterbirds used it mainly for foraging. This study highlights the importance of mangrove in the life cycle of several bird species and their aggregation. Therefore, protection of these coastal habitats should be prioritized in conservation measures.

Impacts of Indian waterfern (Ceratopteris thalictroides (L.) Brongn.) infestation and removal on macroinvertebrate biodiversity and conservation in spring‐fed streams in the Australian arid zone

Abstract Removal of invasive macrophytes is a priority for river managers. However, the ecological effects of macrophyte removal on macroinvertebrate diversity are rarely examined but may be of particular significance in conservation reserves and when threatened species are present. This study investigated the macroinvertebrate fauna inhabiting invasive and native macrophytes in spring‐fed channels in the Millstream‐Chichester National Park, Australia. The effects of waterfern management (periodic hand‐weeding) were examined by comparing assemblages at weeded and unweeded reaches on three occasions. Ceratopteris thalictroides harboured a diverse, insect‐dominated macroinvertebrate assemblage, including the endangered damselfly Nososticta pilbara. Total taxon richness was similar between waterfern and native macrophytes, but macroinvertebrate assemblages differed in the dry season. Damselflies (including N. pilbara) were associated with waterfern‐dominated reaches, whereas dragonfly nymphs were more common among native macrophytes. Weeding altered macroinvertebrate assemblage composition. Some weeded reaches developed assemblages indistinguishable from those in native‐dominated reaches, but others did not. Weeded reaches often supported taxa that were rare or absent from waterfern‐dominated reaches, including suspension feeders, found also in native‐dominated reaches. Odonata are particularly diverse at Millstream, with 18 species recorded. Odonate species richness was significantly lower at weeded reaches than unweeded reaches. Nososticta pilbara and other short‐range endemic species were absent from weeded reaches. As most odonates are univoltine, these adverse effects on local population size may affect species persistence. Invasive macrophyte species may support a high diversity of native invertebrates, including endangered and short‐range endemic species. Furthermore, although hand‐weeding appeared to enable a greater diversity of species to co‐exist, the removal of a large biomass of macrophytes appeared to remove whole cohorts of insect populations from stream reaches, including endangered species. Removal of invasive macrophytes should not be implemented without understanding their effects on invertebrate assemblage composition and life‐cycles.

Integrated management in the Mekong River Basin

The Mekong River is of great importance because of its geographical size, the size of the human population that depends on it, its geopolitical location, and the high diversity of fish and invertebrates that it supports. It is shared by six countries and the need to manage it for the benefit of all has been recognized since the end of World War II (1945). The present Mekong River Commission (MRC) was established through an agreement reached by the four lower Mekong countries (Cambodia, Laos, Thailand and Viet Nam) in 1995 as an agency to assist with planning and promoting sustainable integrated development within the basin. It has been successful in improving technical understanding, developing planning tools and improving cooperation between the four lower Mekong countries. However, integrated management in the Mekong has been inhibited by a number of factors: the lack of participation by two countries, Myanmar and Peoples Republic of China in the MRC; by the poorly coordinated activities of multiple agencies, including unilateral aid agencies, the Asian Development Bank (ADB) and World Bank; and a continuing lack of technical capacity and understanding. The absence of a culture of public participation and the pursuit of narrow short-term national objectives benefitting the powerful continue to be major constraints on integrated management of the Mekong.

Coral reef habitats strongly influence the diversity of macro- and meiobenthos in the Caribbean

Macro- and meiobenthos contribute substantially to the diversity of marine habitats and should account for a significant fraction of the diversity in coral reefs. The aims of the present study are to characterize macro- and meiobenthic communities in a Caribbean coral reef and to analyze the effects of habitat type on the α-, β-, and γ-diversity of free-living nematodes. Two reef sites with four habitat types each were selected: seagrass bed, bare sand, coral rubble, and algal turf. Habitats within sites were adjacent to each other and characterized by their physical architecture, hydrodynamic regime, and foundation species. The diversity of marine communities was high, with eight phyla represented in the macrobenthos and 18 phyla in the meiobenthos. The structure of macrobenthos was strongly associated with the habitat type. This relationship was weaker for meiobenthos, which is likely related to ecological drift, hydrodynamic regime, and macrobenthic influence. The nematode species richness was high at both studied scales: α-diversity ranged from 31 to 83 species per habitat and γ-diversity for the whole reef was 156 ± 4 species. The nematode assemblages consisted of few dominant and many rare species, which is typical of hyperdiverse faunas. The β-diversity was large in the reef with few shared species and the presence of distinctive nematode assemblages adapted to the physical architecture and food availability of each habitat. The results imply that the physical structure and heterogeneity of the coral reef habitats are important for maintaining the high diversity of small invertebrates, especially regarding the richness and turnover of nematode species.