Composition Of Assemblages Research Articles

Seasonal Variations in Macrobenthos Communities and Their Relationship with Environmental Factors in the Alpine Yuqu River

This study investigated the spatial and temporal variations of macrobenthos community structure in the Yuqu River Basin during the dry and wet seasons due to environmental factors. This study quantified the independent and interactive contributions of hydrophysical, hydrochemical, and climatic factors to the community structure through a variance decomposition analysis (VPA). The study findings indicate that during May (the dry season), factors such as water depth, flow velocity, dissolved oxygen, and air temperature exhibit relatively minor fluctuations, rendering the aquatic environment more stable than in the rainy season. This stability is particularly conducive to the maintenance of the macrobenthic community structure and species diversity, which is especially evident in aquatic insects with nesting habits, such as those belonging to the Trichoptera order (including genera like Glossosoma, Glossosomatidae, and Georodes). In contrast, during August (the rainy season), substantial precipitation alters the thermal conditions of the river, increases flow velocity, raises water levels, and introduces a significant influx of organic matter through sedimentation. This distinctive ecological environment fosters unique adaptive strategies among macrobenthic organisms. Notwithstanding a notable decline in species diversity during this particular phase, there is a concurrent increase in the abundance of individual organisms, which is indicative of the populations’ remarkable capacity to swiftly adapt to environmental heterogeneity. Research has demonstrated that macrobenthic communities within the Yuqu River Basin adopt pronounced adaptive tactics that vary significantly between seasons. During the dry season, these macrobenthic fauna rely heavily on the stability of their physical habitat. In stark contrast, they are compelled to navigate and cope with the more intricate and dynamic changes in hydrological and chemical conditions that characterize the rainy season. The presented results uncover the sensitive responsiveness of the macrobenthic fauna to seasonal hydrological and environmental fluctuations in high-altitude river systems and their adaptive strategies under diverse ecological stressors. Arthropods, in particular, exhibit a marked sensitivity to seasonal hydrological and environmental changes. This study delves into the biodiversity of high-altitude river ecosystems, analyzing the ecological environment and the distribution patterns and seasonal variation characteristics of macrobenthic communities. This study aims to examine how diverse seasons and hydroclimatic conditions modulate the composition of macrobenthic assemblages within the tributaries and principal channels of high-altitude river systems, thereby establishing a foundational reference for future water ecosystem assessments in such regions.

Bivalve shell beds in the Triassic of the Sierra De Gádor (Alpujárride complex, Betic Cordillera, SE Spain)

Abstract The Peñón the Bernal section in the Sierra de Gádor comprises a succession of limestones, marly limestones and marls in the upper part of the Gádor unit, which belongs to the Alpujárride Complex in the Internal Zones of the Betic Cordillera. Several shell beds in this section and the locality of La Zarba in the same unit include relatively well-preserved macroinvertebrate assemblages. These beds reflect shell concentrations caused by storms and later colonised by epifaunal communities of cemented, epibyssate and endobyssate bivalves. Sedimentary features, fossil traces, and composition of bivalve assemblages indicate that the succession accumulated in a peritidal environment in a restricted carbonate platform with cyclic changes in water depth. The identified bivalve and ammonoid taxa suggest a Ladinian (Middle Triassic) age for the limestones, marly limestones and marls culminating the Gádor unit, so far considered as Upper Triassic in age. Like in other domains in the Betic Cordillera, the macroinvertebrate fauna has strong affinities with the Sephardic bioprovince.

Nubian Levallois Cores from MIS 5 Alluvial Terraces in the Negev Desert: New Insights into the Middle Paleolithic in the Arid Regions of the Southern Levant

The Negev region is a part of the great desert belt of north Africa and the Arabian Peninsula, a physical and environmental barrier between eastern Africa and southwest Asia. The proximity of the Negev Desert to the Eastern Mediterranean ecological zone to its north, makes it an interesting study area for identifying movements of people and ideas between these areas, in particular during interglacial periods such as Marine Isotope Stage 5 (MIS 5). Not until recently, the archaeological data associated with this stage in the Negev was quite limited, but new studies point to a complex scenario in which several lithic traditions coexisted. One of them was dominated by the Nubian Levallois technology, that is seen by some as a cultural proxy for population movement from Afro-Arabia into the Levant. A comprehensive geoarchaeological survey conducted during the years 2017–2020 revealed dozens of previously unknown Middle Paleolithic findspots in the central and the southern parts of the Negev. Amongst the new findspots, sites with Nubian Levallois cores were identified. The geomorphological contexts of most of these findspots correspond to MIS 5 terraces, as supported by several luminescence ages. A comparison between surveyed sites and excavated MIS 5 sites from the Negev shows differences in the composition of the lithic assemblages. The surface sites include a combination of Nubian cores, centripetal and bidirectional Levallois knapping modes, while the excavated sites are more homogeneous and dominated by centripetal and bidirectional Levallois, or Nubian Levallois, but not both together. We propose that the Nubian core technology in the Negev is part of a distinct lithic tradition, probably originated in regions to the south and the east, whereas the centripetal and bidirectional Levallois are integral part of the known Middle Paleolithic lithic traditions of the Mediterranean ecological zone to the north and likely represent their expansion south into the Negev Desert.

Factors influencing the presence and relative abundance of Didymosphenia geminata: impact on the composition of diatom assemblages over a broad latitudinal gradient in Chilean rivers

This study explored the abiotic factors influencing Didymosphenia geminata blooms and the combined effect of D. geminata and abiotic factors on local diatom assemblages in 13 Chilean watersheds across a broad latitudinal range (37°–47° S). To understand the multi-scale drivers, we used generalized linear mixed-effects models to assess the abiotic factors most influential on D. geminata presence and relative abundance. We then explored the effects of D. geminata and abiotic factors on the α- and β-diversity of diatom assemblages using generalized linear models and permutational analyses of variance, respectively. Three watersheds lacked D. geminata and another three had low relative abundance. Seasonally, the relative abundance of D. geminata was significantly higher in spring than in autumn. We found positive correlations between elevation, river order, pH and D. geminata presence and relative abundance, while water temperature was negatively correlated with D. geminata relative abundance. Diversity indices were significantly influenced by watershed and to a lower extent by the presence of D. geminata. We found significant spatial (i.e. between watersheds along a south–north latitudinal gradient) and temporal (i.e. between seasons) variations in β-diversity of diatom assemblages. Moreover, increasing relative abundance of D. geminata in the assemblage was correlated with lower diatom diversity. In addition, the compositions of diatom assemblages with D. geminata were more alike and less variable than those in non-invaded sites. This study is a first attempt to understand the multi-scale drivers of diatom assemblages in Chilean lotic ecosystems.

Multilevel Analysis of Ground Beetle Responses to Forest Management: Integrating Species Composition, Morphological Traits and Developmental Instability.

This study evaluates the response of ground beetle (Coleoptera: Carabidae) assemblage to forest management practices by integrating species composition, body traits, wing morphology and developmental instability. Traditional approaches that rely on averaged identity-based descriptors often overlook phenotypic plasticity and functional trait variability, potentially masking species-specific responses to environmental changes. To address this, we applied a three-layered analytical approach to address this gap, utilising ground beetle occurrence and morphological trait data from Podyjí National Park, Czech Republic. The first layer assessed assemblage composition with ecological and dietary preferences across control, ecotone and clearing treatments using multivariate techniques. Building on species-level knowledge, the second layer analysed the interaction between coarse traits, such as wing morphology and fine-scale body traits, including body size (proxied by elytron length), head width and last abdominal sternite, to assess their relationship with the different treatments. These interactions were explored as intraspecific wing plasticity can affect functional interpretations. The third layer focused on fluctuating asymmetry as an intraindividual indicator of developmental instability, examining how ground beetles respond to environmental stressors. Our findings revealed: (i) no significant impact of habitat treatments on the presence of specialist species in the assemblage analysis; (ii) analysis of morphological traits highlights the combined influence of a coarse trait, such as wing morphology, and a fine trait, such as head width, which together contribute to the partitioning of assemblages and help distinguish differences in habitat use; and (iii) FA analysis revealed a significant positive association between the second antennal segment of specialist species and litter while displaying a negative association with Collembola. This multilevel analytical framework not only confirms ecological findings but also advances our approach to habitat and species analysis, offering deeper insights into ecosystem dynamics.

Waterbird assemblages of Australia’s largest east-coast wetland complex: environmental determinants of spatial and temporal distribution

Context The extensive Burdekin–Townsville seasonal freshwater wetlands in the Queensland tropics (adjacent to an intertidal Ramsar site) support important waterbird assemblages within and downstream of the Burdekin–Haughton irrigation area. Little evidence is available of the environmental drivers of these assemblages, possibly including the extensive development of irrigated agriculture. Aims We described the composition and dynamics of freshwater waterbird assemblages to identify their environmental determinants and underpin conservation management. Methods We used up to four decades’ worth of records of waterbird assemblages, and collected biophysical data from 57 sites and water quality data for 32 sites. We predicted that these measured variables would determine assemblage composition, thereby elucidating the environmental drivers of the assemblages. Key results In total, 100 waterbird and shorebird species were recorded. Individual samples were strongly nested. Species richness increased with area but density decreased. Richness had a humped relationship with water depth. Linear modelling identified mostly weak relationships between species, assemblages and environmental variables (e.g. nutrients). Abundances mostly increased during the dry season but irrigation tailwater reduced seasonal variation in some wetlands. No apparent change in common species’ assemblages was evident over four decades. Conclusions The wetlands provide extensive, diverse habitats for rich waterbird assemblages, despite impacts of agricultural development. Impacts on waterbirds appear to be buffered by the extent and complexity of the wetland mosaic that includes modified wetlands. Implications Holistic, active management is required to ensure the long-term conservation of habitats for waterbirds and other biota in the Burdekin–Townsville seasonal freshwater wetlands. Inclusion of these freshwater wetlands in the Ramsar site would be beneficial.

Phytoliths in dicotyledons occurring in North-western Europe: Establishing a baseline.

The absence of a modern plant-based 'dicotyledon' phytolith reference baseline impedes the accurate interpretation of fossil phytolith records in archaeological and palaeoecological research within North-western Europe. This study aims to fill this gap by documenting and analysing the phytolith record from modern dicotyledon taxa occurring in this region. Phytoliths were extracted from several plant parts of 117 plant specimens representing 74 species (1-2 specimens/species). The study employed light microscopy to examine phytolith production (non-producer, trace, common, or abundant) and phytolith assemblage composition. The data were analysed statistically to (a) determine the influence of taxonomy and plant part on phytolith presence (absent/present) using a Mixed Model, (b) assess phytolith assemblage variation using a Permutational Multivariate Analysis of Variance (PerMANOVA), and (c) identify patterns among sample groups including segregation for plant part, life form (forbs vs shrubs/trees), and order using a Linear Discriminant Analyses (LDA). Morphotype analysis reveals diagnostic morphotypes and features for specific plant families, genera, and plant parts. LDA effectively segregated plant parts and life forms, though taxonomic groupings showed limited segregation. Phytolith presence (absent/present) was found to vary, influenced by both plant part and taxonomy. For species examined through two specimens, although phytolith production varied considerably, phytolith assemblage composition was consistent. This study establishes a 'dicotyledon' phytolith baseline for North-western Europe, showing that the phytolith record can be informative in terms of plant part and life form and that several phytolith morphotypes and/or features are taxonomically diagnostic below 'dicotyledon' level. The findings constitute a foundation upon which future research can build, refining and expanding our knowledge of the North-western European region.

Variation of functional diversity structure measured as combined species dominance, functional diversity, and functional redundancy in two taxa of ectoparasitic arthropods at two spatial scales: host-associated, ecological, and geographic effects.

The functional diversity structure of a community can be represented as a combination of three additive components (species dominance D, functional redundancy R, and functional diversity Q) (DRQ approach in which different facets of functional differences between species are considered simultaneously). We applied this concept to assemblages of fleas and gamasid mites parasitic on small mammals at continental (across regions of the Palearctic) and regional (across sampling sites in Slovakia) scales and asked: What are the relative effects of host species, biome/habitat type, and geographic locality on the DRQ composition of a parasite assemblage? At the continental scale, regions were partitioned according to predominant biome or geographic position in a continental section. At the regional scale, sampling sites were partitioned according to habitat type or geographic locality. We tested for differences in the functional diversity structure (measured as the DRQ composition) of an ectoparasite assemblage (a) within a host species between biomes/habitat types or continental sections/localities and (b) between host species within a biome/habitat type or a continental section/locality. At both scales, the functional diversity structure of both flea and mite assemblages differed mainly between host species within a biome/habitat or geographic regions/locations, whereas differences in the DRQ composition between biomes/habitats or geographic regions/locations were only detected in a few host species. We compare our results with the results of earlier studies and conclude that the DRQ approach has an advantage over a single diversity metric and allows a better understanding of spatial variation in different facets of ectoparasite diversity.

Fish associated with microhabitats of submerged fallen logs in a lake in the Brazilian Amazon

Microhabitats represent an important factor for fish survival, providing food and shelter, in addition to good temperature conditions and dissolved oxygen levels. One of these temporary microhabitats formed is that of submerged logs, which, due to the flooding of adjacent areas, become available for fish. In this sense, the present study evaluates the composition and structure of fish assemblages associated with submerged logs on the banks of an Amazonian lake and identified the diversity of species according to the hydrological period. Field work was carried out on the banks of Tupé lake, in the lower Negro River, using scoop nets. The sampling was carried out in an area which measured 16 m² (4 m x 4 m) and, within this area, the effort was standardized with the presence of three researchers fishing for approximately one hour in each of the sampling sites. The capture of the fish was carried out with the aid of hand nets (“puçá” and “rapiché”) and sieve. Absolute abundance (N), richness (S), Shannon-Wiener diversity index (H'), Berger Parker dominance (d) and equitability (E) were analyzed. Analysis of variance (p <0.05) was used to verify the temporal variation. A total of 631 specimens were captured, which were distributed in eight families and 25 species, with the orders of Characiformes (67.8%) and Cyprinodontiformes (22.8%) predominating. In the high water period, the highest values of numerical abundance and dominance were observed, while in the low water period, the highest values of species diversity, richness and equitability were found. Therefore, the results presented here can serve as a basis for fisheries management, as well as for conservation measures in these environments that help to maintain fish assemblages.

Contrasting Patterns of Plants, Bees, Hoverflies and Spiders in Different Habitats in a Central European Agricultural Landscape.

Semi-natural grasslands and their biodiversity decline rapidly, although they are key elements of agricultural landscapes. Therefore, there is a need for the re-establishment of semi-natural grasslands in intensively managed farmlands (e.g., via sowing wildflower seeds). Our knowledge, however, is limited on how different arthropod groups may respond to such newly established wildflower fields. This knowledge gap is especially relevant for the Pannonian biogeographical region, and more generally for Central Europe, where there is little to no evidence so far. We aimed to compare three different habitats (i.e., sown wildflower fields (WFF), semi-natural road verges and adjacent crop fields) in terms of their species and individual numbers and assemblage compositions to reveal differences between primary producers (plants), pollinators (bees and hoverflies) and predators (spiders). We selected eight landscapes in Central Hungary within conventionally managed crop areas. We analysed species and individual numbers by generalised linear mixed models (GLMM) and the assemblage composition with non-metric multidimensional scaling for each taxon in the three habitats. Crop, road verge and WFF habitats had distinct assemblages for each studied group, indicating clear separation among habitats. There are, however, contrasting patterns in the diversity measures of the studied groups. Crop fields are the poorest in both species and individual numbers, road verges harboured the highest abundance of spiders, while WFF had the most bees and plants. No clear pattern for hoverflies emerged. Our results suggest that the studied habitats do not harbour all groups in equal share. We propose that the design of future restorations in Central European farmlands should target a diversity of habitat types needed to support a wide range of functional groups.

Unprecedented toxic blooms of Microcystis spp. in 2019 in the Chowan River, North Carolina

The Chowan River flows from southern Virginia through northeastern North Carolina and into the Albemarle Sound, the second largest U.S. estuary. The Chowan, which serves as an important recreational area and provides critical nursery habitat for multiple vulnerable species, has garnered much attention in recent years due to recurrent cyanobacterial harmful algal blooms (cHABs) associated with microcystins (MCs). Here we document unprecedented toxic blooms of Microcystis spp. during summer and fall of 2019 with MC concentrations two to three orders above the recreational guidelines of the Environmental Protection Agency (EPA, 2019). Based on 16S sequencing results in this study and previously published reports, the genus Microcystis emerged as a primary concern within the region. Shifts in assemblage composition, including relative abundance of Microcystis spp. and contributions from potential MC-degraders, linked to overall toxin concentrations and bloom stage. Congeners of varying toxicity, mainly MC-RR and MC-LR, were the most prevalent, corroborating that congeners other than MC-LR should be considered as health risk guidelines are developed. Downstream toxin transport was indicated based on changes in accumulated dissolved MC within the western Albemarle Sound which matched toxin dynamics in the Chowan River. This study provides important novel data on bacterial community composition, MC dynamics, and spatial connectivity for the Chowan River region that can aid monitoring approaches and management strategies for the protection of public health along the Chowan River and within the western Albemarle Sound.

Drivers of Anuran Assemblage Structure in a Subtropical Montane Region.

Elevation gradients provide excellent semi-experimental conditions to investigate how the spatial distribution of biodiversity is shaped by the environment. Here, we investigate how temperature, productivity, and elevation are related to the diversity of anuran assemblages in a montane region of the southern Brazilian Atlantic Forest. We sampled 20 half-hectare plots between 2020 and 2021, distributed along a sharp elevation gradient. Anuran species richness and abundance decreased with increasing elevation. We show a positive relationship between ambient temperature and frog species richness and abundance, highlighting the importance of temperature in shaping assemblages along the elevation gradient. In contrast, productivity did not affect species richness and abundance, suggesting that available energy via resources does not limit local frog diversity. We further observed marked differences in the composition of anuran assemblages between low and high elevation areas, which were related to temperature. Beta diversity is mainly driven by species replacements among assemblages, which were likely related to environmental conditions. These findings highlight the importance of incorporating protected areas that encompass the entire range of elevations to capture the full complement of landscape-scale diversity. This is crucial as species showed limited distributions, and the marked effects of temperature should be explicitly considered under future scenarios of elevated upslope warming.

Human activities and dispersal capacity: key drivers of dung beetle colonization in Mediterranean and Macaronesian islands

Abstract This study examines how geography, environmental factors, and human history shape the composition of dung beetle assemblages on Mediterranean and Macaronesian islands. We analysed 146 islands (27 in Macaronesia and 119 in the Mediterranean), compiling species inventories from extensive literature. Various environmental factors and species traits, such as body size, geographical range, and nesting behaviours, were evaluated using statistical methods, including Simple Matching Coefficient and k-means clustering, to assess species colonization capacities and biogeographical patterns. Our results show that dung beetle assemblages on these islands are more similar to those of the European mainland than to those inhabiting North Africa or the Middle East, particularly on larger and more populated islands. Human-driven processes, including historical colonization, significantly shape the observed trait distributions, diminishing the impact of geographical isolation. Species with traits such as broader geographical ranges, larger body sizes, and paracoprid nesting behaviour exhibited higher colonization success, indicating that species with better dispersal ability and adaptability are more likely to thrive in insular environments. These findings emphasize the complex interplay between natural and human-mediated factors in shaping island biodiversity. Traditional biogeographical theories prioritize isolation as a key driver of species diversity, whereas our study highlights the pivotal role of human activity in facilitating species establishment and persistence. This human influence can override classical island biogeography effects, such as isolation and island size. Our study underscores the need to integrate both ecological and anthropogenic factors when studying island biodiversity and calls for further research into how these forces interact in insular ecosystems.

Random forest models highlight early Homo sapiens habitats and their relationship to lithic assemblage composition

Random forest models highlight early Homo sapiens habitats and their relationship to lithic assemblage composition

Novel Drop‐Sampler for Simultaneous Collection of Stereo‐Video, Environmental DNA and Oceanographic Data

ABSTRACTThere is an increasing interest in environmental DNA (eDNA) as a method to survey marine biota, enhancing traditional survey methods, and a need to ground truth eDNA‐based interpretations with visual surveys to understand biases in both the eDNA and visual datasets. We designed and tested a rapidly deployable, robust method pairing water sampling for eDNA collection and stereo‐video imagery, comparing inferred fish assemblages with interspersed baited remote underwater video (stereo‐BRUV) samples. The system is capable of rapidly collecting simultaneous wide‐field stereo‐video imagery, oceanographic measurements and multiple water samples across a range of habitats and depths (up to 600 m). A platform demonstration was conducted in a no‐take National Park Zone of the Ningaloo Marine Park, Western Australia, with samples being collected whilst the system is resting on the seafloor. Combining simultaneous visual survey data with eDNA species estimates increased the total diversity of the fish assemblage by ca. 6.5% over eDNA estimates alone, whilst the analysis of the assemblage composition sampled by each method revealed significant differences. The platform demonstration highlights the biases of each sampling method and their complementarity to one another. We suggest that these biases will be better understood by advancements that allow eDNA metabarcoding to discriminate the abundance and life stage of marine biota. Furthermore, investigation of the relationship between eDNA metabarcoding data and concomitant imagery‐derived length, age and habitat data is needed.

Variation in the diversity and composition of tree-related microhabitats across climate and human impact gradients on a tropical mountain

Tree-related microhabitats (TReMs) have been proposed as important indicators of biodiversity to guide forest management. However, their application has been limited mostly to temperate ecosystems, and it is largely unknown how the diversity of TReMs varies along environmental gradients. In this study, we assessed the diversity of TReMs on 180 individual trees and 44 plots alongside a large environmental gradient on Kilimanjaro, Tanzania. We used a typology adjusted to tropical ecosystems and a tree-climbing protocol to obtain quantitative information on TreMs on large trees and dense canopies. We computed the diversity of TReMs for each individual tree and plot and tested how TReM diversity was associated with properties of individual trees and environmental conditions in terms of climate and human impact. We further used non-metric multidimensional scaling (NMDS) to investigate the composition of TReM assemblages alongside the environmental gradients. We found that diameter at breast height (DBH) and height of the first branch were the most important determinants of TReM diversity on individual trees, with higher DBH and lower first branch height promoting TReM diversity. At the plot level, we found that TReM diversity increased with mean annual temperature and decreased with human impact. The composition of TReMs showed high turnover across ecosystem types, with a stark difference between forest and non-forest ecosystems. Climate and the intensity of human impact were associated with TReM composition. Our study is a first test of how TReM diversity and composition vary along environmental gradients in tropical ecosystems. The importance of tree size and architecture in fostering microhabitat diversity underlines the importance of large veteran trees in tropical ecosystems. Because diversity and composition of TReMs are sensitive to climate and land-use effects, our study suggests that TReMs can be used to efficiently monitor consequences of global change for tropical biodiversity.

Fossil insect-feeding traces indicate unrecognized evolutionary history and biodiversity on Australia's iconic Eucalyptus.

Fossilized plant-insect herbivore associations provide fundamental information about the assembly of terrestrial communities through geologic time. However, fossil evidence of associations originating in deep time and persisting to the modern day is scarce. We studied the insect herbivore damage found on 284 Eucalyptus frenguelliana leaves from the early Eocene Laguna del Hunco rainforest locality in Argentinean Patagonia and compared damage patterns with those observed on extant, rainforest-associated Eucalyptus species from Australasia (> 10 000 herbarium sheets reviewed). In the fossil material, we identified 28 insect herbivory damage types, including 12 types of external feeding, one of piercing-and-sucking, five of galls, and 10 of mines. All 28 damage types were observed in the herbarium specimens. The finding of all the fossil damage types on extant Eucalyptus specimens suggests long-standing associations between multiple insect herbivore lineages and their host genus spanning 52 million years across the Southern Hemisphere. This long-term persistence, probably enabled through niche conservatism in wet eucalypt forests, demonstrates the imprint of fossil history on the composition of extant insect herbivore assemblages. Although the identities of most insect culprits remain unknown, we provide a list of Eucalyptus species and specific population locations to facilitate their discovery, highlighting the relevance of fossils in discovering extant biodiversity.

Depth drive shifts in the fish and benthic assemblages of the South American Reef System

The low-latitude habitats of the South American reef system have a high endemism and represent important stepping-stones due to the connectivity with Amazon and Caribbean reefs. We provide the first seabed mapping, and analyze the benthic cover and fish assemblages of these extreme reefs. Fleshy macroalgae (2—66% of cover), algal turfs (0—47%), and sponges (3—25%) are the dominant benthic groups. The main reef builders are crustose coralline algae (2—23%) and only four coral species (0 to 18%), mainly the weedy Siderastrea stellata. Cluster analysis distinguished two groups. The first group includes the shallowest reefs (~ 17 m deep) where fleshy macroalgae are abundant together with higher siltation on the reefs (~ 31% covered by sediments). The second group, by contrast, includes the deeper reefs (22.5—27 m), which have much higher algal turf cover, and the lowest sediment cover (4%). The deeper reefs also have the highest cover of corals (18%) and sponges (25%). We recorded a total of 63 fish species, with the deep reefs being the richest. Analysis indicated that the composition of the benthos was considerably more homogeneous across the study area than the composition of fish assemblages, which had a higher turnover of species among reefs. Moreover, we identified the depth of the reef as a variable structuring the benthic assemblages. The fish assemblage is influenced, in turn, by the benthos. Overall, the seabed mapping revealed the existence of a single reef system with high spatial heterogeneity. Our results provide new insights into the structure of these extreme reefs that have evolved under the influence of sediment resuspension, moderate turbidity, and are warmer than other West Atlantic reefs located at middle- and high-latitudes.

Variation in Abundance and Assemblage Composition of Pollinating Insects in Two Protected Areas of Western Haiti

Variation in Abundance and Assemblage Composition of Pollinating Insects in Two Protected Areas of Western Haiti

Deadwood manipulation and type determine assemblage composition of saproxylic beetles and fungi after a decade

The biodiversity crisis calls for immediate restoration of deteriorated and rare habitat. Due to fire suppression and intensive forest management, boreal pine forests of high conservation value are exceptionally rare. Despite decades of restoration research in boreal forests, relatively few studies have evaluated multi-taxon biodiversity response of restoration measures in pine forests. In a Scots pine experiment, we investigated biodiversity patterns of wood-inhabiting fungi and beetles a decade after restoration (prescribed burning and deadwood creation) and forest management (harvest with varying retention). We found that fungi and beetles develop differently and have distinct preferences in deadwood originating from restoration. Standing deadwood supported more species for beetles and lying deadwood for fungi and for both taxa, standing and lying deadwood harboured different species assemblages. Burned deadwood displayed less variable assemblages than unburned deadwood for both organism groups. We found that, after a decade, deadwood type and not harvest with different retention levels better explained diversity patterns of wood-inhabiting beetles and fungi in pine forests. Pine forests are naturally prone to recurring disturbances creating open light conditions. Pine-associated species are therefore likely resistant to disturbance as long as a variety of deadwood resources are present. To accommodate multiple taxa, a variety of substrate and environment types is required. Beetles benefit from standing deadwood while fungi benefit from lying deadwood. To support assemblages with both rapid and slow turnover rates, a combination of recurring restoration and leaving restored stands in the adjacent landscapes is required.