Spatial Patterns Of Abundance Research Articles

Bumble bee diet breadth increases with local abundance and phenophase duration, not intraspecific variation in body size.

Patterns of abundance across space and time, and intraspecific variation in body size, are two species attributes known to influence diet breadth and the structure of interaction networks. Yet, the relative influence of these attributes on diet breadth is often assumed to be equal among taxonomic groups, and the relationship between intraspecific variation in body size on interaction patterns is frequently neglected. We observed bee-flower interactions in multiple locations across Montana, USA, for two growing seasons and measured spatial and temporal patterns of abundance, along with interspecific and intraspecific variation in body size for prevalent species. We predicted that the association between spatial and temporal patterns of abundance and intraspecific variation in body size, and diet breadth, would be stronger for bumble bee compared to non-bumble bee species, because species with flexible diets and long activity periods can interact with more food items. Bumble bees had higher local abundance, occurred in many local communities, more intraspecific variation in body size, and longer phenophases compared to non-bumble bee species, but only local abundance and phenophase duration had a stronger positive association with the diet breadth of bumble bee compared to non-bumble bee species. Communities with a higher proportion of bumble bees also had higher intraspecific variation in body size at the network-level, and network-level intraspecific variation in body size was positively correlated with diet generalization. Our findings highlight that the association between species attributes and diet breadth changes depending on the taxonomic group, with implications for the structure of interaction networks.

Dynamic oceanographic influences on zooplankton communities over the northern Gulf of Mexico continental shelf

Dynamic influences of ocean processes on distribution, abundance, and diversity of zooplankton communities were studied over the continental shelf in the northern Gulf of Mexico (GoM) from 2015 to 2017. Zooplankton sampling was conducted on four summer cruises in the northcentral GoM. Sampling was designed in waters potentially influenced by the Loop Current (LC) and/or Mississippi River discharge to assess the impacts of these two mesoscale features on the abundance and diversity of zooplankton. During the three-year study, the LC displayed distinct spatial-temporal variations in penetration and occurrence in the northern GoM. Environmental conditions (i.e., sea surface temperature, salinity, and dissolved oxygen) varied between months and years sampled, and were significantly different among cruises (ANOVA, p < 0.001). The majority of zooplankton consisted of calanoid copepods (65% ± 7.2%, mean ± SD), while non-copepod taxa were primarily chaetognaths, polychaetes, tunicates, and ostracods (23 ± 9.2%). Species abundance and diversity of zooplankton were significantly correlated with sea surface temperature, salinity, and dissolved oxygen (p < 0.05). Canonical correspondence analysis displayed significant associations between mesoscale features and dominant zooplankton groups among cruises and by taxa (Monte Carlo Permutation Test, p < 0.001). In addition, non-metric multidimensional scaling indicated that zooplankton assemblages were distinct, likely caused by Mississippi River plumes during the study period. As one of the few efforts to examine zooplankton dynamics at a low taxon level over the GoM continental shelf regarding the impact of mesoscale features, this study revealed seasonal (i.e. summer) and spatial patterns in distribution, abundance, and diversity of zooplankton communities subjected to the dynamic physicochemical conditions in the northern GoM, which will continue in a changing climate.

Abundance and diversity patterns and environmental drivers of Peracarida (Arthropoda, Crustacea) macrofauna from the deep sea of the southwestern Gulf of Mexico

We present unique data of abundance, spatial diversity, and bathymetric patterns of the Peracarida communities of the economic and ecological important scarce studied area of the southern Gulf of Mexico. Peracarida macrofauna was collected from 63 sites in a large geographical area (92.67°– 96.70° W, 18.74°–23.04° N) with a wide bathymetric gradient (185–3740 m depth) of the deep-sea southwestern Gulf of Mexico. The samples were obtained onboard the R/V Justo Sierra (Universidad Nacional Autónoma de México, UNAM) using a Reineck-type box corer during four oceanographic cruises (SOGOM 1–4; 2015–2018). We examined the bathymetric and spatial patterns of standardized abundance (ind. m-2) and taxonomic diversity (Hill numbers, q = 0, 1, and 2). Abundance patterns were related to environmental parameters (organic matter, aromatic and aliphatic hydrocarbons, bottom water temperature, dissolved oxygen and grain composition). We collected 684 specimens belonging to 53 Peracarida families of 4 orders (Amphipoda, 19; Isopoda, 17; Tanaidacea, 13; and Cumacea, 4). The most abundant orders were Amphipoda and Tanaidacea, representing 36.4% and 35.8% of the total abundance, respectively, followed by Isopoda (25.1%). Cumacea was the least abundant order (2.7%). The top ten abundant families in order were Apseudidae, Phoxocephalidae, Caprellidae, Desmosomatidae, Nototanaidae, Nannoniscidae, Tanaellidae, Ischnomesidae, Podoceridae, and Agathotanaidae, accounting for 66% of the total relative abundance. The abundance decreased with increasing depth. Highest values were recorded in the northwestern region of the study area and in the Campeche Bay salt domes zone, whereas the lowest abundance values were registered at the abyssal locations and in some sites located in the Coatzacoalcos and Campeche Canyons. The composition and structure of the peracarid community showed shifts related to depth. The major structural abiotic factors of the Peracarida community were: latitude, depth, temperature, and sediment aliphatic hydrocarbons. The diversity based on the three estimated Hill numbers consistently decreased with increasing depth. We recorded intermediate and low diversity values in almost the entire study area, except for the Campeche Bay salt domes zone and northwestern region, where intermediate and high diversity values were registered.

Population size and factors influencing the distribution of the urban pigeon Columba livia f. domestica in Pamplona

The environmental and trophic conditions of cities often give rise to very large populations of urban pigeons Columba livia f. domestica, which can cause local health and heritage problems due to accumulations of their droppings. Estimating the size of pigeon populations and defining their spatial patterns of abundance are therefore crucial for effective pigeon management in built-up areas. This article estimates the abundance of pigeons in Pamplona and the factors that explain the variability of pigeon abundance at local level. The Random Forest model of abundance at a local scale of 0.25 km2 cells had very high explanatory power, although its predictive power decreased due to this species’ gregariousness. Abundance decreased with increasing distance from the city centre, and from historic buildings and large parks, but increased as the proportion of the area covered by parks and built-up areas increased. The rock pigeon population in Pamplona was estimated at 8,030 individuals (95% CI: 6,483–9,860). The estimated density of urban pigeons for Pamplona as a whole was, on average, 218 birds/km2, although this figure varied considerably between habitats and areas: the highest values were measured in urban areas with historic buildings (exceeding 600 individuals/km2; in 35.8% of the 0.25 km2 cells, more than 200 individuals were estimated). Pigeon densities fell to ca. 250 birds/km2 in urban areas lacking large parks or green spaces whether near or far from historic buildings. In the peri-urban areas (i.e. arable fields, scrub and woodland), densities decreased to around 10–50 individuals/km2. In the city of Pamplona, although the population density of urban pigeons did not reach the numbers observed in other northern Spanish cities such as Barcelona, the habitat preference patterns in urban gradients are consistent with those documented in other European regions. We identify specific urban areas for population control and recommend measures such as feeding bans and waste and facade management to make it difficult for urban pigeons to access roosting and breeding sites in buildings.

Using Drones to Reveal the Distribution and Population Abundance of Threatened Dasyatid Rays at a Nursery Site in Seychelles

Drones are becoming increasingly valuable tools for studying species in marine environments. Here, a consumer-grade drone was used to elucidate the distribution and population abundance of two threatened dasyatid rays, Pastinachus ater and Urogymnus granulatus, in a remote marine protected area in the Republic of Seychelles. Over six weeks in March and April 2023, a total of 80 survey flights, covering an area of 3.2 km2, recorded 1262 P. ater and 822 U. granulatus. Findings revealed previously unresolved high-use areas for both species, which almost exclusively used sandy areas within the habitat and were found in greater abundances in areas closer to the shoreline. Spatial patterns in abundance were strongly correlated between species, with both often found in mixed-species groups. The site was shown to support large populations of both species with total population abundance estimates of 2524 (2029–3019 95% CI, 0.1 CV) for P. ater and 2136 (1732–2539 95% CI, 0.09 CV) for U. granulatus. This study highlights the applicability of drones in acquiring highly useful data for delineating critical habitats and informing the adaptive management of marine protected areas.

Modelling the habitat preferences of the NE-Atlantic Sea cucumber Holothuria forskali: Demographics and abundance

Sea cucumbers' historical demand, together with the depletion of several traditional species in the market, has popularized new target species from new fishing grounds. Holothuria forskali is one of those emergent species in the trade market. However, it is a species for which there is no relevant information to allow sustainable stock management. Fundamental knowledge of the populations' structure and habitat preferences are key elements without which any measure is inconsequent. This work aims to fill that gap by modelling temporal and spatial patterns of abundance and demographic structure of this species in a NE-Atlantic area, as a function of environmental features.For a period of 15 months, nine regular sampling campaigns collected data on density, individual length, individual conditions of occurrence (e.g. sheltered, on sand, on algae cover) and environmental parameters (water column, sediment, substrate cover and type), using random transects throughout a costal rocky-reef, considering habitat heterogeneity and substrate types. To determine the species' habitat preferences Generalized Linear Models were used to model density and demographic structure of the species as a function of environmental conditions. The models revealed that the main drivers shaping the distribution of H. forskali are neither abiotic nor biotic parameters of the water column, but physical stressors, like current intensity and depth, and substrate type in a patchy distribution pattern. Estuarine conditions are generally avoided, although with a size-dependent opportunistic strategy. Larger individuals show temporal and spatial displacement patterns towards suitable reproductive conditions (pre-breeding aggregation) and favourable feeding grounds and smaller size-classes tend to aggregate in higher numbers in more stable environments.Sustainable sources for market supply, like aquaculture, are still a long way from commercial production. So, these results are fundamental to support effective conservation measures for stock management of H. forskali.

Species diversity and distribution pattern of venerable trees in tropical Jianfengling National Forest Park (Hainan, China)

Venerable trees are precious natural-cum-cultural heritage and an important component of regional biodiversity, with significant social, cultural and ecological values. A thorough understanding of their spatial patterns in relation to environmental factors can foster co-management for conservation and sustainable resource use. The Jianfengling National Forest Park in tropical China is a unique and rare primary tropical forest protected area with exceptionally high biodiversity and a rich endowment of venerable trees. This study evaluated the venerable tree stock regarding botanical makeup and factors shaping spatial patterns. We collected detailed tree data (species, age, dimensions, location, etc.) and environmental variables (elevation, slope and soil). The environmental variations were analyzed concerning tree abundance, species richness and tree age. The results identified 2134 venerable trees from 72 species, 55 genera and 30 families. Lithocarpus fenzelianus dominated with maximum importance value, followed by Cyclobalanopsis patelliformis, Madhuca hainanensis, Altingia obovata and Castanopsis tonkinensis. The top-ranking species were predominantly Fagaceae members. The age pattern demonstrated an inverted J-shape, with mainly 100-299 years trees and a few >500 years. DBH, tree height, and crown width displayed an approximately normal distribution. Spatial distributions by age tiers were uneven, with more in the northeast part. The altitudinal gradient significantly influenced the spatial patterns of tree abundance and species richness. The unimodal distribution marked tree and species concentration at circa 600 m mid-elevation. The findings have implications for venerable-tree conservation and management in tropical protected areas with similar threatened and remnant-tree status.

Recruitment of Juvenile Snapper (Lutjanidae) in the Middle Florida Keys: Temporal Trends and Fine-Scale Habitat Associations

Juvenile recruitment is a major factor in the establishment and maintenance of local population structures of coral reef fishes. An understanding of the factors that affect juvenile recruitment and survival help explain spatial and temporal patterns in adult abundance, especially of commercially and recreationally fished species. Here, we examined the distribution and juvenile recruitment of 5 snapper species: Mutton Snapper (Lutjanus analis), Lane Snapper (L. synagris), Schoolmaster (L. apodus), Gray Snapper (L. griseus), and Yellowtail Snapper (Ocyurus chrysurus) collected in 1,314 seine samples conducted between 2007 and 2019 in the Middle Florida Keys. We use a generalized linear modeling routine to assess juvenile recruitment of each species as a function of temporal, environmental, and benthic habitat variables. Interannual variability in juvenile recruitment ranged between 2 and 15—fold differences in mean predicted abundance between the highest and lowest producing years by species. Predicted recruitment varied dramatically by species in 2010 following a historic cold spell in south Florida. Three of the 5 species (Lane Snapper, Yellowtail Snapper, and Schoolmaster) exhibited the lowest observed yearly recruitment in that year, while Gray Snapper recruitment peaked. For all species, recruitment indices exhibited strong seasonal trends with peak abundances observed in the fall. Aquatic vegetation type, aquatic vegetation cover, distance from shore, and water temperature were the most important predictors of abundance. Results of this study highlight species—specific preferences for settlement habitat, demonstrate the importance of local—scale recruitment processes, and provide updated, management—relevant juvenile abundance indices for shallow water snapper in the Middle Florida Keys.

Feeding ecology of the Red-and-green Macaw (Ara chloropterus; Gray 1859) in a habitat mosaic from Cerrado.

In the Brazilian Cerrado, the Red-and-green Macaw (Ara chloropterus) populations are facing an accelerated rate of habitat loss. Despite this, their feeding areas and primary food sources remain poorly understood. In this study, I assessed the relationship between the diet of the Red-and-green Macaw and available food resources in a habitat mosaic from the fragmented Cerrado in Mato Grosso do Sul State, Brazil. Red-and-green Macaws fed on 20 native and five exotic species, mainly in dry habitats (Cerrado, dry forest, and an urban area along the Maracaju Cliffs) during the dry season, while year-round foraging in the riparian vegetation (Aquidauana River and streams). Then, the number of feeding macaws paralleled variations in food abundance and diversity, besides the number of food species. On the other hand, by using a wide variety of abundant foods, macaws' diet breadth presented high values throughout the year. The seasonal consumption of large-seeded fruits across the habitat mosaic displayed a gradient ranging from the urban area to dry habitats, along which macaws ate from exotic to Cerrado species. In this respect, Terminalia catappa seeds and Mangifera indica fruit pulp were important for Red-and-green Macaws in the urban area during the wet season, while Caryocar brasiliense seeds comprised the same in the Cerrado. At this site, both Dipteryx alata and Buchenavia tomentosa seeds composed much of the Red-and-green Macaws' diet during the dry season. Between those habitats, in the watercourse vegetation, macaws frequently foraged on palm fruits across seasons. Therefore, throughout the year, the abundance and variety of food resources strongly influenced the number of foraging Red-and-green Macaws across the habitat mosaic. Understanding the effect of varying seed availability on the spatial and temporal abundance patterns of Red-and-green Macaws, which primarily feed on large-seeded species, is central to developing effective conservation strategies. Due to the accelerated habitat loss, the Maracaju Cliffs emerge as crucial for the Red-and-green Macaw among the Cerrado remnants of Mato Grosso do Sul.

Spatial and temporal patterns of scyphozoan jellyfish abundance and growth in Icelandic coastal waters – a climate change perspective

ABSTRACT Scyphozoan jellyfish in Icelandic waters have received limited attention, despite apparent recent increases in blooms and changes in the regional oceanographic setting. The objectives of this study were to describe the species composition, abundance, phenology, and growth of scyphomedusae around Iceland and explore changes by comparing our findings with reports from the 1930s. Specimens were collected with a Bongo net in five regions around Iceland in the spring, summer, and autumn of 2008. Three jellyfish species were collected in the study, Aurelia aurita, followed by Cyanea capillata, and C. lamarckii. In the western and northwestern parts of Iceland, A. aurita abundance was highest in spring and summer, whereas in the North and East, abundances were highest in autumn. Cyanea capillata was not encountered in the Southwest, but in the west, Northwest, and North. There, numbers were highest in spring, whereas in the East, abundance was highest in autumn. Clockwise coastal current dispersal and regional interconnectivity are indicated. Weight-specific growth rates varied between 7.0 and 8.5% d−1 for A. aurita and 11.1 and 15.7% d−1 for C. capillata and are comparable to rates from often food-limited ecosystems at temperate latitudes. Presented evidence suggests that ephyrae and small medusae appear earlier in the season and in previously (in the 1930s) not occupied regions, while some regions (Southwest for C. capillata) were not populated anymore.

Waterbird community changes in the Wilderness Lakes, South Africa (Part 1 of 3): Herbivores and omnivores

Global and regional degradation and loss of aquatic systems can negatively affect wetland-dependent waterbirds. The Wilderness Lakes Complex in South Africa, which incorporates the Wilderness Ramsar site, supports populations of 68 waterbird species including eight which periodically occur in globally significant (1% population) numbers. The study aimed to document long-term spatial and temporal (including seasonal) patterns of abundance of herbivorous waterbirds in the Wilderness Lakes Complex, and where possible identify potential causes for observed trends. The abundance of waterbirds on these wetlands was determined biannually from 1992 to 2019, with counts conducted from a boat following a standardised route. Historical abundance data from the 1980s was also used to describe long-term abundance changes. Observed seasonality of four herbivorous waterbirds differed from published accounts. Long-term abundance trends indicated a combination of declining, increasing and stable populations which, in several instances, differed from regional (southern African) assessments. Significant long-term decreases have occurred in five herbivorous species in the lakes complex (Common Moorhen Gallinula chloropus, Red-knobbed Coot Fulica cristata, Yellow-billed Duck Anas undulata, Cape Shoveler Anas smithii, Cape Teal Anas capensis), whereas increases have occurred in two species (Spur-winged Goose Plectropterus gambensis, Egyptian Goose Alopochen aegyptiaca). Similar types of change occurred across multiple waterbodies, and in different seasons. The similarity of trends in spatially separated wetlands suggested either high interconnectivity of populations between wetland systems and/or some drivers of change of mobile species being broad scaled and regional, rather than system specific. Local reasons for changes potentially include increasing extent of cultivated fields, a proliferation of emergent macrophytes and loss of open sandbanks, changing food availability, increasing disturbance, and disease.Conservation implications: The fundamental character of the Wilderness Ramsar site has changed, with reduced abundance of several previously abundant herbivorous waterbirds. Drivers of change in species abundances are multifaceted, complex, and frequently poorly understood. Recommended local corrective actions include the management of emergent macrophytes, avian diseases, disturbance, and water quality.

Waterbird community changes in the Wilderness Lakes, South Africa (Part 2 of 3): Shorebirds

Globally, many shorebirds, particularly the smaller migratory waders are declining, which can be attributed to multiple factors throughout their ranges. The Wilderness Lakes Complex in South Africa comprises two estuarine systems, that support diverse waterbird communities, including 17 abundant shorebirds. The study aimed to document long-term spatial and temporal patterns of abundance of shorebirds in the Wilderness Lakes Complex, and where possible identify potential causes for observed trends. The abundance of waterbirds on these wetlands was determined biannually from 1992 to 2019, with counts conducted from a boat following a standardised route. Historical abundance data from the 1980s were also used to describe long-term abundance changes. Ten shorebirds showed seasonal differences in abundances. Significant long-term decreases in abundance have occurred in seven shorebirds (Wood Sandpiper Tringa glareola, Marsh Sandpiper Tringa stagnatilis, Curlew Sandpiper Calidris ferruginea, Ruff Philomachus pugnax, Grey Heron Ardea cinerea, Greater Flamingo Phoenicopterus ruber, Black-winged Stilt Himantopus himantopus) and increases in three species (African Spoonbill Platalea alba, Little Egret Egretta garzetta, Glossy Ibis Plegadis falcinellus). Similar types of population changes occurred across multiple waterbodies and in different seasons. The similarity of shorebird abundance trends in spatially separated wetlands suggests either high interconnectivity of populations between wetlands systems and/or prominent drivers of change being broad scaled rather than system specific. Local reasons for changes potentially include the increasing spread of emergent macrophytes and resultant loss of open sandbanks, changing hydrodynamics, and alien fish proliferation, all likely changing food accessibility, as well as periodic high disturbance by waterbody users.Conservation implications: Changes in the abundances of several shorebirds, particularly small migratory waders, are substantial, with multiple likely local, regional and international drivers acting accumulatively. Recommended corrective actions include continuing involvement in the development and implementation of policies for waterbird conservation, and local management of emergent macrophytes, disturbance, and water level variability.

Waterbird community changes in the Wilderness Lakes, South Africa (Part 3 of 3): Diving piscivores and scavengers

Estuarine waterbodies typically support diverse and abundant waterbird communities. However, global environmental degradation as a result of anthropogenic activities is leading to species level changes in biodiversity, with top predators such as piscivorous waterbirds being particularly vulnerable to ecosystem changes. The study aimed to document long-term spatial and temporal patterns of abundance of piscivorous and scavenging waterbirds in the Wilderness Lakes Complex (WLC) in the Garden Route National Park, South Africa, and where possible identify potential causes for observed trends. The abundance of waterbirds on these wetlands was determined biannually from 1992 to 2019, with counts conducted from a boat following a standardised route. Historical waterbird abundance data from the 1980s were also used to describe long-term abundance changes. Eight of the species exhibited seasonal variability in abundance with most, excluding Common Tern Sterna hirundo, being more abundant in winter. Substantial changes occurred in the abundance of several species over the four-decade study period, notably increases in Cape Cormorant Phalacrocorax capensis and Great Crested Grebe Podiceps cristatus, and decreases in Common Tern and Black-necked Grebe Podiceps nigricollis. Long-term abundance trends indicate a combination of declining, increasing, and stable populations. Although some species have undergone contrasting abundance changes on different waterbodies in the WLC the dominant pattern was a similar direction of change on most or all waterbodies and in different seasons. Local reasons for changes probably include loss of sandbanks, changing prey availability, and the absence of recreational disturbance on some waterbodies.Conservation implications: Drivers of changes in the abundances of piscivores are likely to be multifaceted, functioning on multiple spatial and temporal scales, and affecting different species in different ways. Recommended local corrective actions include managing emergent macrophyte encroachment on sandbanks, reducing recreational disturbance, managing processes affecting indigenous fish stocks, and protecting nesting sites.

Deep topographic proteomics of a human brain tumour

The spatial organisation of cellular protein expression profiles within tissue determines cellular function and is key to understanding disease pathology. To define molecular phenotypes in the spatial context of tissue, there is a need for unbiased, quantitative technology capable of mapping proteomes within tissue structures. Here, we present a workflow for spatially-resolved, quantitative proteomics of tissue that generates maps of protein abundance across tissue slices derived from a human atypical teratoid-rhabdoid tumour at three spatial resolutions, the highest being 40 µm, to reveal distinct abundance patterns of thousands of proteins. We employ spatially-aware algorithms that do not require prior knowledge of the fine tissue structure to detect proteins and pathways with spatial abundance patterns and correlate proteins in the context of tissue heterogeneity and cellular features such as extracellular matrix or proximity to blood vessels. We identify PYGL, ASPH and CD45 as spatial markers for tumour boundary and reveal immune response-driven, spatially-organised protein networks of the extracellular tumour matrix. Overall, we demonstrate spatially-aware deep proteo-phenotyping of tissue heterogeneity, to re-define understanding tissue biology and pathology at the molecular level.

Identifying community assembling zones and connectivity pathways in the Tropical Southwestern Atlantic Ocean

Dispersal is more intense in the ocean than on land because most marine taxa present planktonic life stages that are transported by currents even without specific morphological traits. Thus, species dispersal shapes the distribution of biodiversity along seascapes and drives the composition of biodiversity assemblages. To identify marine assembling zones which characterise spatial areas particularly prone to receive and retain similar animal assemblages from the regional pool of species through passive dispersal, we propose a community‐based approach grounded on Lagrangian simulations of plankton dispersal. This novel approach was applied to communities (coast, outer shelf, slope, seamounts and islands; 0–80 m depth) of the Tropical Southwestern Atlantic and used to assess connectivity pathways. For that, we classified the modelled particles in 15 categories according to biological traits (planktonic life duration and spawning habitat) of representative planktonic communities. From the hierarchical clustering of the multivariate matrix containing the amount of arriving particles from each category in each cell we defined 14 assembling zones. Results highlighted that the assembling zones were mostly shaped by the degree of exposure to currents and the presence of mesoscale features (eddies, recirculation) derived from the interaction between these currents and coastlines. The boundaries, dispersal and connectivity patterns of these zones consistently align with local and regional in situ spatial distribution and abundance patterns of organisms, and provide an appropriate basis for the formulation of ecological hypotheses in the metacommunity framework to be tested in situ, such as the balance between species sorting and mass effect assembling archetypes. This approach, when coupled with the knowledge of other processes shaping communities' structure and distribution, provides important insights for regions and animal groups for which knowledge is limited or absent, and more generally allows for a comprehensive overview of the distribution of distinct communities and connectivity pathways along marine environments.

Fine-scale spatial patterns of deep-sea epibenthic fauna in the Laurentian Channel Marine Protected area

Ecological processes at local to global scales impact spatial patterns in abundance and distribution of megafauna. Fine-scale patterns have rarely been investigated through explicitly spatial analytical methods in the deep sea and have been assumed random, uniform, or similar to neighbouring areas. We used spatial statistics (Moran's I, Gi*, and local Moran's I) to identify significant megafaunal patterns (0–100s of meters; 8 focal taxa) in the Laurentian Channel Marine Protected Area, based on imagery from a remotely operated vehicle, using 8 parallel transects at each of 7 stations. Our results included 2 spatial scales, station level (0.256 km2) and paired transect level (0.004 km2). We found local areas with significant aggregations (e.g., Pennatula sp. 2 and Hexacorallia (SC.) spp.) and patches extending for ∼7–27 m, and in one case for ∼155 m. Patchiness also existed between neighbouring images (≤10 m apart). Patterns varied among taxa within stations and for the same taxon among transect pairs. Station-level patterns appear to be related to geological factors, such as BPI (bathymetric position index), benthoscape, pockmarks, and slope. We propose that patterns at the transect level were likely caused by biological factors, possibly related to reproduction due to local currents and retention, or community interactions (e.g., competition). Fine-scale patterns should be considered to ensure effective sampling designs when using fine-scale tools (e.g., imagery), and for establishing accurate community metrics (e.g., abundance and diversity). Our study is relevant to future ecological research, linking patterns to processes, as well as monitoring and conservation in deep-sea ecosystems.

Loss, resilience and recovery of kelp forests in a region of rapid ocean warming.

Changes in kelp abundances on regional scales have been highly variable over the past half-century owing to strong effects of local and regional drivers. Here, we assess patterns and dominant environmental variables causing spatial and interspecific variability in kelp persistence and resilience to change in Nova Scotia over the past 40 years. We conducted a survey of macrophyte abundance at 251 sites spanning the Atlantic coast of Nova Scotia from 2019 to 2022. We use this dataset to describe spatial variability in kelp species abundances, compare species occurrences to surveys conducted in 1982 and assess changes in kelp abundance over the past 22 years. We then relate spatial and temporal patterns in abundance and resilience to environmental metrics. Our results show losses of sea urchins and the cold-tolerant kelp species Alaria esculenta, Saccorhiza dermatodea and Agarum clathratum in Nova Scotia since 1982 in favour of the more warm-tolerant kelps Saccharina latissima and Laminaria digitata. Kelp abundances have increased slightly since 2000, and Saccharina latissima and L. digitata are widely abundant in the region today. The highest kelp cover occurs on wave-exposed shores and at sites where temperatures have remained below thresholds for growth (21 °C) and mortality (23 °C). Moreover, kelp has recovered from turf dominance following losses at some sites during a warm period from 2010 to 2012. Our results indicate that dramatic changes in kelp community composition and a loss of sea urchin herbivory as a dominant driver of change in the system have occurred in Nova Scotia over the past 40 years. However, a broad-scale shift to turf-dominance has not occurred, as predicted, and our results suggest that resilience and persistence are still a feature of kelp forests in the region despite rapid warming over the past several decades.

New interactive functional indicator approach for river health assessment in an Asian temperate river: Comprehensive analysis of water chemistry, physical habitat, land use, and the biological disturbance of invasive alien species

Elucidating the responses of aquatic communities to environmental (e.g., chemical, habitat, and flow regime) and biological disturbances is essential to the maintenance and restoration of healthy ecosystems. This study investigated the interactions between environmental and biological disturbance factors and functional indicators of ecological health in 99 sampling sites along a temperate river. Variance tests and multivariate statistical tools, such as non-metric multidimensional scaling (NMDS) and generalized linear models (GLMs), were employed to evaluate the responses of functional indicator guilds and ecological river health to various in-stream chemical, physical, habitat, and land-use pattern factors along with the biological impact of invasive alien species (IAS). Variance testing revealed significant variation (χ2 > 6.2 and p < 0.05) in common species abundance and ecological functional guilds among spatial groups according to chemical pollution levels, land-use intensity, and land-use patterns. NMDS analysis and GLMs based on trophic, habitat, and tolerance guilds, and the results of the multi-metric index of biological integrity for fish, indicated statistically significant patterns in response to environmental disturbance, particularly chemical degradation associated with nutrient (nitrogen and phosphorus) enrichment and organic pollution, loss of gravel and cobble substrates, and intensified agricultural land use. The spatial pattern of IAS abundance was also significantly correlated with the alteration in fish community structures. This study underscores the often-unnoticed impact of high IAS abundance on river health, and its interactions with chemical and physical degradation resulting from agricultural and urban land uses. In summary, this study highlights the importance of addressing multiple environmental and biological disturbances to maintain and conserve the health of river systems.

Spatial patterns of zooplankton abundance, biovolume, and size structure in response to environmental variables: a case study in the Yellow Sea and East China Sea

Spatial patterns of zooplankton abundance, biovolume, and size structure in response to environmental variables: a case study in the Yellow Sea and East China Sea

Roles of depth, current speed, and benthic cover in shaping gorgonian assemblages at the Palm Islands (Great Barrier Reef)

Gorgonians are a diverse and conspicuous component of coral reef ecosystems, providing habitat structure that supports unique assemblages of fishes and invertebrates. Evaluating their overall importance as ecological engineers requires an understanding of their spatial patterns of distribution, abundance and assemblage composition, and the biophysical factors that drive these patterns. No baseline data are available on the spatial patterns of distribution of gorgonians for the Great Barrier Reef. In this study, we quantified the abundance, genera richness, and composition of gorgonian assemblages using video surveys at three depths (5, 10, and 15 m) at 16 locations at the Palm Islands, an inshore island group in the central Great Barrier Reef. We compared gorgonian abundance and genera richness between depths and assessed the role of benthic habitat in structuring gorgonian communities. We also conducted a preliminary investigation of the potential role of water currents in driving gorgonian spatial patterns in the Palm Islands, using in situ current meters. Gorgonian abundance and genera richness consistently increased with depth, although the magnitude of the depth effect varied among locations. Abundance increased with increasing percent cover of rubble and conversely declined with increasing cover of hard corals. The composition of gorgonian assemblages also varied among depths, with whip (Junceella, Viminella) and fan (Acanthogorgia, Anthogorgia, Annella) growth forms being dominant at depths of 5 and 10 m, and branching (Dichotella, Icilogorgia) and candelabrum (Ctenocella) forms being dominant at 15 m. The shallow gorgonian assemblage was associated with high coral cover, whilst the deeper assemblage was associated with high per cent cover of rubble, turf and/or macroalgae. This study highlighted that the abundance, diversity, and composition of gorgonian assemblages on coral reefs in the Palm Islands are determined by a range of biophysical factors linked to depth. Further work is required to isolate the primary drivers of these depth-related effects and evaluate their relative importance.