Composition Of Benthic Assemblages Research Articles

Predation effects on benthic communities are maximized by greater taxonomic richness and diversity in Subtropical SW Atlantic

Predation effects on benthic communities are locally influenced by biological and ecological processes, such as recruitment, competition, and habitat features. We studied three Southwestern Atlantic (SWA) subtropical reef habitats (a rhodolith bed, a coral reef, and a rocky shore) to test if the predation effects on benthic communities overwhelm the habitat-context differences. We deployed panels protected and unprotected from predators on the three habitats, retrieved the panels after 45 days and quantified the recruitment of benthic sessile organisms. Despite differences in the composition of benthic assemblages, the effect of predation was mainly driven by the reduction of the ubiquitous polychaeta Spirorbidae in the three habitats. For the rhodolith bed, which supported a higher taxonomic richness and diversity than the other habitats, predation effects were higher and also driven by the reduction of other taxa. Although we recorded a greater predation effect in more diverse reefs, we attribute this result to small scale traits intrinsic to each habitat instead large-scale oceanographic patterns. Our results add pieces into the debate about how predation affects marine habitats and the importance of small-scale understanding for direct management actions in marine conservation.

Shifts in dominance of benthic communities along a gradient of water temperature and turbidity in tropical coastal ecosystems.

Tropical coastal benthic communities will change in species composition and relative dominance due to global (e.g., increasing water temperature) and local (e.g., increasing terrestrial influence due to land-based activity) stressors. This study aimed to gain insight into possible trajectories of coastal benthic assemblages in Raja Ampat, Indonesia, by studying coral reefs at varying distances from human activities and marine lakes with high turbidity in three temperature categories (<31°C, 31-32°C, and >32°C). The benthic community diversity and relative coverage of major benthic groups were quantified via replicate photo transects. The composition of benthic assemblages varied significantly among the reef and marine lake habitats. The marine lakes <31°C contained hard coral, crustose coralline algae (CCA), and turf algae with coverages similar to those found in the coral reefs (17.4-18.8% hard coral, 3.5-26.3% CCA, and 15-15.5% turf algae, respectively), while the higher temperature marine lakes (31-32°C and >32°C) did not harbor hard coral or CCA. Benthic composition in the reefs was significantly influenced by geographic distance among sites but not by human activity or depth. Benthic composition in the marine lakes appeared to be structured by temperature, salinity, and degree of connection to the adjacent sea. Our results suggest that beyond a certain temperature (>31°C), benthic communities shift away from coral dominance, but new outcomes of assemblages can be highly distinct, with a possible varied dominance of macroalgae, benthic cyanobacterial mats, or filter feeders such as bivalves and tubeworms. This study illustrates the possible use of marine lake model systems to gain insight into shifts in the benthic community structure of tropical coastal ecosystems if hard corals are no longer dominant.

Long-term impacts on estuarine benthic assemblages (2015–2020) after a mine tailing spill in SE Brazil

The Rio Doce estuary was critically impacted in 2015 by the world's largest mining tailing spill, with still unclear long-term effects on the aquatic biota. Here we present a long-term (2015 to 2020) assessment of estuarine benthic assemblages, where we demonstrate that despite a decline in the absolute concentrations of potentially toxic elements; sediment contamination is still above pre-impact conditions. The presence of these contaminants is likely responsible for a continued low habitat quality for the benthic fauna, characterized by a reduction of 96 % of the macroinvertebrate density and persistent change in the benthic assemblage composition. Our study supports previous work indicating the long-term nature of pollution impacts in estuaries, and demonstrate that although water quality levels were quickly adequate under regulatory terms, they largely lack significance to the overall ecosystem health assessment, as they are not related to the recovery of bottom- dwelling assemblages in estuarine ecosystems.

Tropicalization shifts herbivore pressure from seagrass to rocky reef communities.

Climate-driven species redistributions are reshuffling the composition of marine ecosystems. How these changes alter ecosystem functions, however, remains poorly understood. Here we examine how impacts of herbivory change across a gradient of tropicalization in the Mediterranean Sea, which includes a steep climatic gradient and marked changes in plant nutritional quality and fish herbivore composition. We quantified individual feeding rates and behaviour of 755 fishes of the native Sarpa salpa, and non-native Siganus rivulatus and Siganus luridus. We measured herbivore and benthic assemblage composition across 20 sites along the gradient, spanning 30° of longitude and 8° of latitude. We coupled patterns in behaviour and composition with temperature measurements and nutrient concentrations to assess changes in herbivory under tropicalization. We found a transition in ecological impacts by fish herbivory across the Mediterranean from a predominance of seagrass herbivory in the west to a dominance of macroalgal herbivory in the east. Underlying this shift were changes in both individual feeding behaviour (i.e. food choice) and fish assemblage composition. The shift in feeding selectivity was consistent among temperate and warm-affiliated herbivores. Our findings suggest herbivory can contribute to the increased vulnerability of seaweed communities and reduced vulnerability of seagrass meadows in tropicalized ecosystems.

Disentangling trawling impact from natural variability on benthic communities

Various environmental parameters such as temperature, depth and currents influence the composition and distribution of benthic assemblages. However, the impact of trawling on benthic communities depends on their species composition since not all benthic species are equally sensitive to trawling. Moreover, trawling can have effects on benthic species similar to some natural disturbances, such as a local increase in turbidity. Thus, species adapted to these natural disturbances may be resistant to a certain level of trawling. This study evaluates the joint influence of environmental parameters and trawling pressure on four functional sensitivity indices in three environmentally contrasted areas: the English Channel, the Gulf of Lion and the eastern coast of Corsica, the two latter being located in the Mediterranean Sea. The different environmental parameters influencing the behaviour of these indices were identified in each of the study areas. These parameters were divided into two groups according to the type of influence they have on the benthic community. The first group of variables, used for modeling “Scope for Growth” (SfG), relates to the resilience of species, while the second, “Disturbance” (Dist), concerns their resistance to physical impacts. This work highlighted that the distribution of benthic species in the English Channel is mainly linked to physical disturbances and therefore to their resistance, whereas it is mainly parameters linked to the resilience of communities that influence the distribution of benthic fauna in the Mediterranean. The effect of abrasion could be distinguished from the natural environmental disturbances in the English Channel and Gulf of Lion where trawling was found to have a significant effect on functional sensitivity indices. The composition and distribution of benthic communities in Corsica, did not seem to be influenced by trawling pressure.

Long-term changes in the macrobenthic assemblages at a harbour sediment disposal site in the southern North Sea

This study focussed on the long-term, sediment-driven changes of macrobenthic assemblages in dredged harbour sediment from Rotterdam harbour disposed of in excavated sand extraction pits off the Dutch coast. Macrobenthic species and sediment grain size composition were studied in samples from two disposal sites and the surrounding environment over ten years after the cessation of disposal activities.There was a strong association between the sediment granulometry and the benthic assemblage composition. Shortly after the last discharge, the top layer of the sediments in the pits contained 20%–60% mud (particles <63 μm) and was colonised by benthic species typical for these sediments. The pit sediments and benthic assemblages contrasted strongly with the surrounding medium-coarse sediment, extremely low in mud (<0.01%). Over eight to ten years, the top layers of the disposal sites became significantly less muddy (ca. 5%–15% mud), and the benthic assemblages changed over this period from mud-favouring species dominated by annelids to species preferring fine sand with relatively low mud percentages dominated by molluscs. The two different disposal sites converged in sediment composition and benthic assemblages over the ten years of monitoring. The contrast with the medium-coarse sediments with very low mud percentages remained even after this period. The use of sand extraction pits as disposal sites for dredged harbour sediments may be seen as an economically sound beneficial use option in dredged material management, albeit with long-term ecological effects.

Benthic Assemblage Composition of South Atlantic Seamounts

Seamounts and oceanic islands rise from the seafloor and provide suitable habitat for a diverse range of biological assemblages including Vulnerable Marine Ecosystems (VMEs). Whilst they have been the focus of some work globally, there has been little description of the biological and physical environments of seamounts in the South Atlantic Ocean. In this study, we characterized benthic assemblage composition from 13 seamounts and oceanic islands spanning 8–40°S within the exclusive economic zones (EEZs) of Ascension Island, Saint Helena and Tristan da Cunha. Drop camera imagery was collected between 170 and 1000 m. All fauna present in images were identified and quantified, and multivariate statistics were used to describe biological assemblages and identify their environmental drivers. Benthic communities of temperate regions (Tristan da Cunha archipelago) were shown to be distinct from those found in the tropics, with latitude and depth identified as key environmental drivers of assemblage composition. Our results are consistent with the current understanding of the biogeography of the South Atlantic, both in terms of the distinction between tropical and temperate regions, and the influence of depth and water mass structure on assemblage distribution. Faunal assemblages are similar to those observed in the North Atlantic in terms of functional groups. VMEs are present within the EEZs of all three territories and are potentially protected from some threats by large marine protected areas (MPAs). Our imagery, data and analyses provide a baseline for south Atlantic seamounts so that future monitoring can establish whether existing protected status is sufficient to conserve both unique biodiversity and considerable potential for vital ecosystem services.

Catchment to sea connection: Impacts of terrestrial run-off on benthic ecosystems in American Samoa

Variation in water quality can directly affect the composition of benthic assemblages on coral reefs. Yet, few studies have directly quantified nutrient and suspended particulate matter (SPM) to examine their potential impacts on benthic community structure, especially around high oceanic islands. We assessed the spatio-temporal variation of nutrients and SPM across six sites in American Samoa over a 12-month period and used exploratory path analysis to relate dissolved inorganic nutrients, land use, and natural and anthropogenic drivers to benthic assemblages on adjacent shallow reefs. Multivariate analyses showed clear gradients in nutrient concentrations, sediment accumulation and composition, and benthic structure across watersheds. Instream nutrients and land uses positively influenced reef flat nutrient concentrations, while benthic assemblages were best predicted by wave exposure, runoff, stream phosphate and dissolved inorganic nitrogen loads. Identifying locality-specific drivers of water quality and benthic condition can support targeted management in American Samoa and in other high islands.

Invertebrate Responses to Restoration across Benthic and Hyporheic Stream Compartments

River restoration is a multi-billion-dollar business, yet it is unclear whether benthic community health, which is routinely monitored, can be used as a proxy for the health of the hyporheos. Applying a Before-After-Control-Impact approach to a UK case study, we compared the effects of removing an impoundment on the hyporheos with effects on the benthos. We compared invertebrate biological traits that we expected to respond to the restoration. We constructed sample-size based diversity curves and determined β-diversity between compartments and reaches. Two years post-restoration, hyporheic taxon richness was significantly lower in the restored reach compared to the control. However, three years post-restoration taxon richness was significantly higher in the impact reach. The composition of the control and impact reach hyporheos was most dissimilar at the first sampling time point post-restoration and at this time there was a universal decrease in the relative abundance of burrowing organisms respiring through gills. We did not detect a signal of restoration on benthic assemblage diversity and composition, perhaps because reach-scale restorations can be overwhelmed by catchment-scale disturbances. Thus, the hyporheos and the benthos responded differently to restoration. Given the importance of the hyporheic zone in the provision of ecosystem function and services, it is clear that it should be included in future monitoring protocols that aim to assess river restoration success.

Cohabiting with litter: Fish and benthic assemblages in coastal habitats of a heavily urbanized area

Anthropogenic litter negatively impacts the marine environment and threatens biodiversity. At the same time, it represents a suitable substrate for the settlement of sessile species, thus potentially altering composition and structure of soft bottom benthic assemblages. By using a Remotely Operated Vehicle (ROV), we hereby investigated patterns of abundance, distribution, and origin of benthic litter in three subtidal habitats of a heavily urbanized area and tested whether litter distribution related to patterns of fish and mega- and macro-benthic diversity. Litter accumulation mostly occurred on soft bottoms, while rocky substrata were the least affected, albeit being particularly threatened by sea-based pollution. As expected, the highest biodiversity was observed on rocky bottoms, hosting notable biogenic formations (Cladocora caespitosa, Leptogorgia sarmentosa) despite the area is historically affected by anthropogenic activities. No correlation was found between biota and marine litter, suggesting that litter does not apparently influence biodiversity and distribution of the investigated assemblages.

Ecological enhancement of breakwater upgrades: size and type of rocks used influence benthic communities

Existing coastal breakwaters are ageing and will need to be upgraded to withstand additional forces associated with rising sea levels and storms. Structural upgrades can affect taxa living on or adjacent to breakwaters. These impacts can be mitigated by ecological engineering of breakwaters, which can enhance habitat quality without losing their primary purpose of protection. A recently upgraded breakwater at Coffs Harbour, NSW, Australia was eco-engineered to use boulder fields to mitigate impacts on a critically endangered alga (Nereia lophocladia) living on and adjacent to the infrastructure. Over a year, we assessed the effect of different rock sizes (small versus large), types (greywacke versus granite) and orientations (top versus bottom) on the composition and diversity of benthic taxa. N. lophocladia has yet to recruit to the eco-engineered habitat; however, we found rock size, type and orientation significantly influenced overall benthic assemblage composition, at least at one of the sites. Furthermore, the bottom of the rocks had a higher taxonomic diversity than the top side, and assemblages on native greywacke rocks were more diverse than those on granite, but only at one of the two sites. Overall, the magnitude of differences in benthic assemblage structure and diversity showed substantial temporal and spatial variation, with no clear temporal trends or successional patterns. Our results indicate that the ecological outcomes of coastal protection infrastructure upgrades could be improved by including native rocks of a range of different sizes in multiple patches and layers.

Do wider riparian zones alter benthic macroinvertebrate assemblages’ diversity and taxonomic composition in neotropical headwater streams?

Abstract: Aim The maintenance and condition of riparian vegetation are important factors for conserving headwater streams and their species diversity. Thus, variations in the width of a riparian zone can have dramatic effects in the structure and functioning of the adjacent freshwater ecosystem. In this study, we aimed to determine if increased riparian zone width changed the benthic assemblages’ structure (diversity, taxonomic and functional composition) in headwater streams. Methods We tested two predictions: (1) increased riparian zone width will change the diversity and taxonomic composition of benthic macroinvertebrate assemblages because narrow riparian zones do not buffer the anthropogenic impacts from the surrounding landscape; (2) wider riparian zones will change benthic macroinvertebrate assemblages’ functional structure, due to changes to energetic input and quality. To test the first prediction, we assessed the benthic macroinvertebrate assemblages’ taxonomic composition, richness and Shannon-Wiener diversity index. To test the second prediction, we assessed functional feeding groups (FFG) and metrics based on their proportion. Results Our results showed that our first prediction was not corroborated, because taxonomic structure and diversity did not show significant variation with increased riparian zone width. Our second prediction was partially corroborated, because there were significant alterations in the functional structure of benthic macroinvertebrate assemblages between the narrowest riparian zone width (30 m) and the others two (50 and 100 m). Conclusions Our results suggest that, contrary to the Brazilian Federal Law 12651/2012, 30-m wide riparian zones are insufficient to protect headwater stream ecosystem functioning.

Fish and benthic invertebrate relationship and their association to environmental variables in tropical sandy beaches

Fish and benthic invertebrates are important groups that inhabit shallow coastal areas. Many studies use these two groups separately to answer questions related to environmental relationships, but few assess the correlation between these two groups. This study aimed to assess correlation between richness and composition of fish and benthic invertebrate assemblages and to evaluate their responses to environmental variables in sandy beaches in a tropical coastal area in south-eastern Brazil. We tested for a correlation between fish and benthic invertebrates and evaluated which environmental variables influenced each group. Fish and invertebrate taxonomic richness were not correlated across sites. In addition, the two groups were not significantly correlated, even after controlling the effects of the environmental variables. The taxonomic richness of the two groups were influenced by different set of environmental drivers: fish were influenced mainly by the physicochemical variables, being positively correlated with salinity and dissolved oxygen, and negatively with temperature, whereas invertebrates richness were related mainly to granulometric variables, decreasing in fine and very fine sediment. Fish and invertebrate showed similar patterns with more influence of environmental variables than biotic variables that had comparatively more effects on the invertebrate than on the fish assemblage. Spatial segregation in species distribution along the beaches were found with the Gerreid fish predominating in semi-exposed beaches whereas the sparid Diplodus argenteus, the haemulid Orthopristis ruber and the clupeids Harengula clupeola and Sardinella brasiliensis predominated in the exposed beaches. The Polychaetae families Syllidae and Dorvilleidae, and isopod of the family Cirolanidae predominated in semi-protect beaches, whereas polychaetas of the families Glyceridae and Saccocirridae predominated in the exposed beaches. In this study, we showed that fish and benthic invertebrates are influenced by different environmental variables in tropical sandy beaches and no significant correlation was found between these two taxonomic groups. Our findings are a step to a better understanding of the fish-benthic invertebrate relationship and a contribution to management policies aiming the conservation of tropical coastal areas.

First simultaneous assessment of macro- and meiobenthic community response to juvenile shellfish culture in a Mediterranean coastal lagoon (Thau, France)

Abstract Shellfish aquaculture has the potential to alter benthic assemblage composition with subsequent modifications of ecosystem functioning. While the impacts of aquaculture on the taxonomic structure of macro- and — to a lesser extent — meiofauna, have been widely studied, the functional changes of these communities remain relatively unknown. The recent development of biological trait analysis (BTA) has made it possible to produce information about how ecosystem functioning could change across specific terrestrial or aquatic system. In the present study, we used a BTA in parallel with standard taxonomic analysis to evaluate how well the two approaches detected the potential influence of juvenile oyster culture on the benthic community in the French Mediterranean Thau Lagoon. Two sites were sampled under farm structures and compared with two reference sites beyond the influence of farming. This study is the first detailed parallel description of macro- and meiofauna (nematodes). A total of 118 and 41 taxa were determined for macrofauna and nematodes respectively. Some taxa were more abundant or exclusively observed under farm structures such as Chaetozone gibber and Neanthes acuminata for macrofauna and Daptonema fallax and Anticoma eberthi for nematodes. Overall, our results indicate that biological traits and functional indices both detected the impact of shellfish culture on benthic assemblages, whereas macrofauna taxonomic indices revealed no difference. Our results thus suggest that trophic and ecological groups are particularly good indicators of the effects of shellfish culture. This study confirms the relevance of the functional approach, and more generally of multi-index approaches, to detect the influence of aquaculture on benthic communities. Further work is required to test multiple traits in different regions and under different systems, but this work paves the way for environmental impact assessment using a trait based approach.

Coral species composition drives key ecosystem function on coral reefs.

Rapid and unprecedented ecological change threatens the functioning and stability of ecosystems. On coral reefs, global climate change and local stressors are reducing and reorganizing habitat-forming corals and associated species, with largely unknown implications for critical ecosystem functions such as herbivory. Herbivory mediates coral–algal competition, thereby facilitating ecosystem recovery following disturbance such as coral bleaching events or large storms. However, relationships between coral species composition, the distribution of herbivorous fishes and the delivery of their functional impact are not well understood. Here, we investigate how herbivorous fish assemblages and delivery of two distinct herbivory processes, grazing and browsing, differ among three taxonomically distinct, replicated coral habitats. While grazing on algal turf assemblages was insensitive to different coral configurations, browsing on the macroalga Laurencia cf. obtusa varied considerably among habitats, suggesting that different mechanisms may shape these processes. Variation in browsing among habitats was best predicted by the composition and structural complexity of benthic assemblages (in particular the cover and composition of corals, but not macroalgal cover), and was poorly reflected by visual estimates of browser biomass. Surprisingly, the lowest browsing rates were recorded in the most structurally complex habitat, with the greatest cover of coral (branching Porites habitat). While the mechanism for the variation in browsing is not clear, it may be related to scale-dependent effects of habitat structure on visual occlusion inhibiting foraging activity by browsing fishes, or the relative availability of alternate dietary resources. Our results suggest that maintained functionality may vary among distinct and emerging coral reef configurations due to ecological interactions between reef fishes and their environment determining habitat selection.

Composition and diversity of benthic macroinvertebrates in a Brazilian Cerrado stream

ABSTRACT This study aimed to analyse the diversity and composition of benthic macroinvertebrate assemblages in the dry and rainy seasons in a Brazilian Cerrado stream, where it was hypothesized that the dry season has higher diversity and it differs in terms of organism composition in relation to the rainy season. Sampling was carried out in the dry (May and August/2016 and August/2017) and rainy seasons (November/2016 and February and November/2017). Individuals were identified at the family level and classified according to functional feeding group (FFG). There were 3,776 individuals, in which Chironomidae was the most abundant taxon with 2,226 organisms. The FFG with the highest number of individuals and species richness were collector-gatherer and predator, respectively. The species richness was higher in the dry season than in the rainy season. The ordinance generated by NMDS showed that there was no distinction in the composition of the assemblage between the dry and rainy seasons. Seasonal variations do not alter the abundance and composition of the benthic macroinvertebrate assemblage, but the species richness does decrease in rainy seasons.

Acoustic Complexity Index to assess benthic biodiversity of a partially protected area in the southwest of the UK

Abstract The soundscape of the marine environment is a relatively understudied area of ecology that has the potential to provide large amounts of information on biodiversity, reproductive behaviour, habitat selection, spawning and predator–prey interactions. Biodiversity is often visually assessed and used as a proxy for ecosystem health. Visual assessment using divers or remote video methods can be expensive, and limited to times of good weather and water visibility. Previous studies have concluded that acoustic measures, such as the Acoustic Complexity Index (ACI), correlate with visual biodiversity estimates and offer an alternative to assess ecosystem health. Here, the ACI measured over 5 years in a Marine Protected Area (MPA) in the UK, Lyme Bay, was analysed alongside another monitoring method, Baited Remote Underwater Video Systems (BRUVs). Two treatments were sampled annually in the summer from 2014 until 2018 with sites inside the MPA, as well as Open Control sites outside of the MPA. Year by year correlations, which have been used elsewhere to test ACI, showed significant correlations with Number of Species and ACI. However, the sign of these correlations changed almost yearly, showing that more in-depth analyses are needed. Multivariate analysis of the benthic assemblage composition (from BRUVs) was carried out by Permutational Multivariate Analysis of Variance (PERMANOVA) using Distance Matrices. Although not consistently correlating with univariate measures, the ACI was significantly interacting with the changing benthic assemblage composition, as it changed over time and protection (Inside vs Outside the MPA). ACI showed potential to allude to shifting benthic communities, yet with no consistency when used alongside univariate measures of diversity. Although it is not without its own disadvantages, and thus should be developed further before implementation, the ACI could potentially reflect more complex changes to the benthos than simply the overall diversity.

Spatial variation in the benthic community composition of coral reefs in the Wakatobi Marine National Park, Indonesia: updated baselines and limited benthic community shifts

AbstractCoral reefs have experienced extensive degradation across the world over the last 50 years as a result of a variety of stressors operating at a range of spatial and temporal scales. In order to assess whether declines are continuing, or if reefs are recovering, detailed baseline information is required from across wide spatial scales. Unfortunately, for some regions this information is not readily available, making future reef trajectories difficult to determine. Here we characterized the current benthic community state for coral reefs in the Wakatobi region of Indonesia, one of the most biodiverse marine regions in the world. We surveyed 10 reef sites (5, 10 and 15 m depth) to explore spatial variation in coral reef benthic communities and provide a detailed baseline. Previous data (2002–2011) were available for coral, sponges, algae and soft coral at six of our study sites. Using this information, we determined if any changes had occurred in dominance of these benthic groups. We found that benthic assemblage composition differed significantly over relatively small spatial scales (2–10 km) and hard coral cover was highly variable, ranging from 7–48% (average 19.5% ± 1.5 SE). While coral cover appears to have declined at all sites where data were available since 2002, we found little evidence for widespread increases in other benthic groups or regime shifts. Our study provides a comprehensive baseline dataset for the region that can be used in the future to determine rates of change in benthic communities.

Spatial variability in benthic assemblage composition in shallow and upper mesophotic coral ecosystems in the Philippines

Mesophotic coral ecosystems (MCEs) have received increasing attention in recent years in recognition of their unique biodiversity and also their potential importance as refuges from disturbance events. However, knowledge of the composition of MCEs and how they vary in space is lacking in many regions, particularly the Coral Triangle biodiversity hotspot. Here, we compared the benthic components and coral genera composition between shallow-water reefs (SWRs, 8–13 m depth) and upper MCEs (30–40 m) in four locations in the Philippines that are exposed to differing environmental conditions. Coral cover, abundance, and generic diversity were lower in MCEs than SWRs at three of the four locations. Benthic composition and coral generic composition also varied significantly among locations for both shallow and deep sites. Differences in benthic composition among sites was due primarily to variation in hard corals, macroalgae, sand and silt, while variation in coral assemblage was due to differences in abundance of encrusting Porites, branching Acropora, branching Seriatopora. Our results showed that the composition of MCE communities varied significantly from adjacent shallow reefs, but also among MCEs in differing geographic locations. Furthermore, our results suggest disturbances affecting shallow-water reefs, particularly sedimentation, also negatively impact MCEs, and that depth therefore provides no potential refuge from these disturbances. We recommend that conservation of MCEs consider spatial variability in community composition among sites, and urge further research to better understand the spatial variation in the composition of MCE communities in the Philippines.

The effect of substrate disturbance on benthic invertebrates in old-growth broad-leaved forest and planted conifer forest basin streams in Japan

ABSTRACTDisturbances such as heavy rainfall impact benthic invertebrate assemblages in streams and other lotic systems. In temperate Japan, the steep topography means that even modest rainfall can result in significant substrate disturbance. Impacts of this disturbance on benthic invertebrates were examined in the following 1 week and compared in streams of an old-growth broad-leaved forest (OBF) and a planted conifer forest (PCF). Disturbance in this study occurred by kicking the stream substrate. The number of individuals and genera in both forest types decreased after disturbance and gradually recovered over time, but no difference in recovery was observed between the OBF and PCF streams. Benthic invertebrate assemblage composition in both forest types changed depending on the days from disturbance, and differences in recovery between the OBF and PCF streams were observed in the composition of benthic invertebrate assemblages. Recovery patterns of individual taxa after disturbance were also different. Complete recovery was not observed 1 week after disturbance in either forest type, suggesting more time was required to reestablish pre-disturbance invertebrate community composition.