Macrofaunal Diversity Research Articles

IDENTIFIKASI DIVERSITAS MAKROFAUNA TANAH DI AREA TAMBANG PANAS BUMI MUTUBUSA DESA SOKORIA KECAMATAN NDONA TIMUR

Soil macrofauna is animals that have a body size of 2-20 mm. The main place of life for macrofauna is not only above but also underground. The purpose of this study was to determine the diversity of soil macrofauna and environmental conditions on forest land and agricultural land in the Mutubusa Geothermal Mine area. The selection of research sites using the purposive sampling method and The sampling technique was carried out by the monolith sampling method. Observational variables in this study were diversity index, relative frequency, density index, and relative density. The results of the diversity analysis show that there are ten types of soil macrofauna, that is; Cockroaches, Millipedes, Spiders, Ants, Conch, Earthworms, Crickets, Grasshoppers (H' = 1.67), Mixed Fields (H' = 1.32), and Coffee Fields (H' = 1.28). While the density of soil macrofauna in candlenut land is 2.9%, forest land is 0.2%, mixed land is 1.5% and coffee land is 0.4%. The highest important value index in candlenut land was snail species, amounting to 39%, while in forest and mixed land, the highest important value index was ant species, respectively, 41% and 67%.

Biodiversity of coastal epibenthic macrofauna in Eastern Canadian Arctic: Baseline mapping for management and conservation

Arctic ecosystems are changing rapidly due to global warming, industrial development, and economic growth. However, the ecological consequences for these ecosystems are difficult to predict due to limited knowledge on species abundance, distribution, and biodiversity patterns. This study evaluated the diversity and assemblage composition of epibenthic macrofauna in shallow coastal areas from five Eastern Arctic locations with increasing economic and shipping activity. Benthic trawls (n=198) were conducted in nearshore coastal habitats of Anaktalak Bay (Labrador), Churchill (Manitoba), Deception Bay (Quebec), Iqaluit (Nunavut), and Milne Inlet (Nunavut), at depths between 3 and 30 m. Diversity and assemblage composition were compared at various taxonomic levels from phylum to species and correlations with broad oceanographic variables were investigated to identify potential drivers of biodiversity. The spatial variability of benthic assemblages was also assessed within each study location. A total of 297,417 macroinvertebrates was identified, belonging to 900 taxa. Abundance and taxonomic richness were highest in Anaktalak Bay. Shannon-Wiener diversity was higher in Anaktalak Bay, Iqaluit, and Milne Inlet than in Churchill and Deception Bay. Churchill showed the lowest diversity metrics among locations. No relationships were observed between diversity and depth, chlorophyll-a, particulate organic carbon, sea surface temperature, or sea ice duration. Assemblages differed among locations at all taxonomic levels, with the highest dissimilarities at the species level; however, dispersion of samples within-groups was significant, suggesting that factors other than locations (e.g., habitat type) influence assemblage composition. While Churchill, Deception Bay, and Iqaluit showed distinct local spatial patterns in diversity metrics and assemblage composition, no patterns were detected in Anaktalak Bay and Milne Inlet. This study represents one of the largest systematic assessments of coastal epibenthic biodiversity in the Canadian Arctic. It identifies patterns of biodiversity and assemblage composition and provides a baseline for studies of community change and the development of informed management and conservation strategies for Arctic coastal ecosystems.

Stressors Increase the Impacts of Coastal Macrofauna Biodiversity Loss on Ecosystem Multifunctionality

There is substantial evidence that biodiversity underpins ecosystem functioning, but it is unclear how these relationships change with multiple stressors in complex real-world settings. Coastal zones are affected by numerous stressors (for example, sediment input and nutrient runoff from land) and the cumulative effects of these stressors may result in pronounced and unexpected changes in the functioning of ecosystems. To investigate the cumulative effects of turbidity and elevated nutrients on coastal biodiversity-ecosystem functioning relationships, we performed a large-scale field experiment manipulating in situ sediment porewater ammonium concentrations and measured multiple ecosystem functions related to carbon fixation and mineralisation in 15 estuaries with varying levels of turbidity. The results indicated that the benthic macrofauna diversity (species richness, abundance, and functional richness) declined with increased porewater ammonium concentrations and there were clear thresholds in light levels at the seafloor in relation to the biodiversity-ecosystem function relationships. Multifunctionality indices (an integrated index of all measured functions) in moderately turbid and turbid estuaries (daily mean seafloor PAR < 420 µmol m−2 s−1) decreased with the loss of macrofauna biodiversity. Functioning in low-turbidity estuaries (daily mean PAR > 420 µmol m−2 s−1) however remained relatively constant, suggesting that they were more resilient against the nutrient-induced biodiversity loss. Our results demonstrate that ecosystems already stressed by stressors that alter functional performance (turbidity) may be more prone to loss of overall functioning if biodiversity is reduced by another stressor (nutrient enrichment), highlighting the potential snowballing effects of cumulative change.

Land-use intensification reduces soil macrofauna biomass at the community but not individual level

Land-use intensification and climate change are main threats to the abundance and diversity of soil macrofauna. However, little is known about their biomass in response to these concurrent drivers. Here, we investigated the biomass responses of soil macrofauna along a land-use intensity gradient of five land-use regimes (i.e., from extensively-used grassland to conventional cropland) under two climate scenarios (ambient vs. future). We found that land-use intensification (but not climate change) significantly reduced soil macrofauna biomass at the community rather than individual level. Further, the community structure of soil macrofauna based on total biomass data varied with land-use type (i.e., grasslands vs. croplands). Collectively, our findings suggest that land-use intensification can negatively shift the community biomass patterns of soil macrofauna consistently under both ambient and future climates in agroecosystems.

SOIL MACROFAUNA AND MESOFAUNA COMMUNITY ON AGRICULTURAL LAND IN PLIKEN VILLAGE, KEMBARAN DISTRICT, BANYUMAS REGENCY

Soil is a habitat for various types of fauna, especially macrofauna and soil mesofauna. In general, fertile soil can be found on land used for agricultural activities. The purpose of this study was to determine and reveal the community structure of soil macrofauna and mesofauna which includes individual count, diversity, and dominance as well as environmental quality on agricultural land in Pliken Village, Kembaran District, Banyumas Regency in 2021. The study was carried out in January-June 2021. by using survey method and purposive random sampling technique. Sampling of soil macrofauna and mesofauna was carried out in three locations, namely agricultural land in the west, north, and south of the village. Data sampling was carried out in the morning (07.00-09.00 am) and at night (19.00-21.00 am) 6 times with an interval of once a month. Soil macrofauna and meofuana that had been obtained were identified using the Taxonomy and Identification Key book. An Introduction to the Study of Insects and other references related to the identification of soil macrofauna During the study, 2717 soil macrofauna were found which belong to 15 Orders, 31 Families and 40 Species, while for soil mesofauna, 500 individuals were obtained which belong to 14 Orders, 18 Families. and 21 species.The highest individual count for soil macrofauna came from the Formicideae family (86.86%), while the highest individual count for soil mesofauna came from the Isotomideae family (27%). The index of soil macrofauna diversity on agricultural land in Pliken Village ranged from 0.997- 1,789 with an average of 1,287 which means the level of diversity is moderate, while the index Soil mesofauna diversity ranges from 1.13 to 2.15 with an average of 1.65 which means the level of diversity is moderate. Soil macrofauna dominance index is moderate with a range of 0.264 - 0.546 which indicates that there is still dominance by certain soil macrofauna, namely the Formicideae (ant) family, while the soil mesofauna dominance index ranges from 0.13 to 0.38 with an average of 0.23 which indicates the absence of a predominant species. The environmental quality of agricultural land in Pliken Village is categorized as good to support the life of macrofauna and soil mesofauna. Keywords : Soil Macrofauna, Soil Mesofauna, Individual Count, Diversity, Dominance, Pliken Village Agricultural Land

Habitat variability and faunal zonation at the Ægir Ridge, a canyon-like structure in the deep Norwegian Sea.

The Ægir Ridge System (ARS) is an ancient extinct spreading axis in the Nordic seas extending from the upper slope east of Iceland (∼550 m depth), as part of its Exclusive Economic Zone (EEZ), to a depth of ∼3,800 m in the Norwegian basin. Geomorphologically a rift valley, the ARS has a canyon-like structure that may promote increased diversity and faunal density. The main objective of this study was to characterize benthic habitats and related macro- and megabenthic communities along the ARS, and the influence of water mass variables and depth on them. During the IceAGE3 expedition (Icelandic marine Animals: Genetics and Ecology) on RV Sonne in June 2020, benthic communities of the ARS were surveyed by means of a remotely-operated vehicle (ROV) and epibenthic sledge (EBS). For this purpose, two working areas were selected, including abyssal stations in the northeast and bathyal stations in the southwest of the ARS. Video and still images of the seabed were usedtoqualitatively describebenthic habitats based on the presence of habitat-forming taxa and the physical environment. Patterns of diversity and community composition of the soft-sediment macrofauna, retrieved from the EBS, were analyzed in a semiquantitative manner. These biological data were complemented by producing high-resolution bathymetric maps using the vessel’s multi-beam echosounder system. As suspected, we were able to identify differences in species composition and number of macro- and megafaunal communities associated with a depth gradient. A biological canyon effect became evident in dense aggregates of megafaunal filter feeders and elevated macrofaunal densities. Analysis of videos and still images from the ROV transects also led to the discovery of a number ofVulnerable Marine Ecosystems (VMEs) dominated by sponges and soft corals characteristic of the Arctic region. Directions for future research encompass a more detailed, quantitative study of the megafauna and more coherent sampling over the entire depth range in order to fully capture the diversity of the habitats and biota of the region. The presence of sensitive biogenic habitats, alongside seemingly high biodiversity and naturalness are supportive of ongoing considerations of designating part of the ARS as an “Ecologically and Biologically Significant Area” (EBSA).

Macro Faunal Diversity in Date Palm Plantation Soils of Yola, Adamawa State, Nigeria

This research assessed the macro-faunal diversity in soil of date palm plantation of Modibbo Adama University, Yola, Adamawa State. Parameters evaluated included; assemblage and diversity of soil macro invertebrates based on growth performances of the date palm. The plantation was divided according to growth variabilities. Assessment of macro fauna species was carried out using plots of 20m × 20m which was randomly selected, using plots of 1m x 1m that where laid at each anger point,Top soil for biological assessment of soil samples, were collected using trowels at depths ranging from 0-30cm depth. The soil samples was immediately spread on board of about 60cm2 and sorted for the presence of macro fauna. Soil macro-invertebrates ‘identification and enumeration. Soil macro-invertebrate assemblage was analyzed for diversity indices of species using relevant formulae. Results showed a total of 648 macro fauna scattered within the study area. Seventeen (17) Families of macro fauna were also identified in the study. Lumbricus terrestris (earthworm), the Heterotermes species (termites) and those belonging to the Formicidae family (ants) were the groups having the highest number of individuals. Leading to the conclusion that soil Macro fauna were present in the study area. However, the numbers of macro fauna were very active in the date palm plantation soil. This is an indication that strong relationship exists between macro fauna-invertebrates the date palm trees.

Land use effects on soil macrofauna communities in a mountainous region of southwest Guizhou, China

An experiment to compare the effects of land use types on soil and macrofauna characteristics was conducted in a mountainous region of southwestern China. Soil physical and chemical properties and soil macrofauna were investigated in four land use types: natural grassland, mixed pasture of Dactylis glomerata L. and Trifolium repens L., mixed pasture of Holcus lanatus L. and Trifolium repens L., and cropland planted with annual Brassica napus L. and Zea mays L. rotation. The results showed that natural grassland, mixed pasture and cropping increased soil pH (23.0%–36.0%), soil organic matter (69.1%–73.9%, except the cropland with a decrease of 18.9%), total nitrogen (346.2%–738.5%), available nitrogen (389.9%–482.7%), available phosphorus (61.9%–303.6%) and available potassium (326.2%–481.4%). The taxonomic richness of macrofaunal communities was lower in the mixed pasture and cropped land than in natural grassland, with the Shannon’s index and Menhinick index being negatively related to soil organic carbon content. The mixed pasture maintained the abundance and diversity of soil macrofauna. The short-term cessation of utilization and management facilitated the restoration of soil macrofaunal communities. This study shows that pasture/grazing or leaving fallow for a year after cropping were able to better sustain macrofaunal communities in this mountainous region.

Assessment of macro-faunal diversity of nipa swamp in Bisagu, Aparri, Cagayan, Philippines

Abstract. Taguiam JMB, Bayani GU, Pacris Jr. FA, Banadero RR, Baloloy MV. 2022. Assessment of macro-faunal diversity of nipa swamp in Bisagu, Aparri, Cagayan, Philippines. Biodiversitas 23: 1852-1856. Nipa (Nypa fruticans) is one of the most common, widely distributed, and useful trees in the mangrove forest of Southeast Asia. It is being utilized in the production of roof thatching, wine and vinegar, and recent scientific studies have been done for the utilization of nipa sap in the production of bio-ethanol. Moreover, nipa has also contributed ecologically as it acts as a barrier during typhoons and storm surges helps prevent soil erosion along the banks of villages near river areas. The study area is located in barangay Bisagu, Aparri, Cagayan, Philippines where nipa plantation covers 550.51 ha and is utilized by the community. As we all know, mangroves areas as home to aquatic animals thus the study conducted takes on the diversity of macrofaunal species in a nipa-dominated mangrove area. Sampling areas were constructed, the proximal, middle and distal quadrat with 10 m by 10 m dimensions. Species collected in the area yield 11, where 10 is successfully identified and 1 species is not identified. Results showed that macrofaunal species in a nipa-dominated mangrove area show very low diversity. Shannon-wiener diversity index of the community showed a result of only 0.97457 and its equitability at 0.04, which concluded as low species evenness distribution.

Multifractal and joint multifractal analysis of soil invertebrate fauna, altitude, and organic carbon

ABSTRACT The objectives of this study were to evaluate the degree of multifractality of the spatial distribution of altitude, organic carbon concentration, and invertebrate fauna diversity, and to characterize the degree of joint multifractal association among these variables. Soil sampling was performed every 20 m across a 2,540 m transect, with a total of 128 sampling points in a sugarcane area in Goiana municipality, Pernambuco State. For each sampling point, the altitude, organic carbon concentration, and macrofauna diversity (diversity indices and functional groups) were evaluated. Spatial distributions of altitude, organic carbon concentration, and macrofauna diversity were characterized by the generalized dimension spectrum (Dq) and singularity spectrums [f(α) versus α], which presented multifractal behavior with different degrees of heterogeneity in scales. Joint multifractal analysis was useful for revealing the relationships at multiple scales between the studied variables, as demonstrated by the non-detected associations using traditional statistical methods. To quantify the spatial variability of edaphic fauna based on the multiple scales and association sets in the joint dimension, the impact of agricultural production systems on biological diversity can be described. All of the studied variables displayed a multifractal behavior with greater or lower heterogeneity degree depending on the variable, with altitude and organic carbon being the most homogeneous attributes.

Effects of topsoil transposition on the taxonomic and functional diversity of macrofauna of highly degraded soil

AbstractTopsoil transposition has been identified as an environmental restoration technique capable of accelerating regeneration in degraded areas. In addition to the seed bank, topsoil contains invertebrates and microorganisms essential in ecological succession. This study evaluated the temporal variation in the macrofauna community structure in an experiment with topsoil transposition. We hypothesized that the morphospecies richness, functional groups and macrofauna biomass would be higher in the plots with topsoil and native vegetation compared with plots with no topsoil. We further hypothesized that the composition of macrofauna community and the proportion of functional groups in the topsoil and the reference plots would become more similar over time. The community was compared between plots that received topsoil, plots that did not receive topsoil and plots in a natural vegetation, over 14 months. The macrofauna biomass and the diversity of functional groups were equivalent in the degraded area and the topsoil. The effect of treatment on richness depended on time, and it was possible to observe higher values of macrofauna richness in the topsoil compared with the degraded area in some months. The compositions of the macrofauna communities in the degraded area and the topsoil showed greater similarity to each other. In contrast, the reference area showed the greatest dissimilarity with the other treatments. In general, the macrofauna community in the topsoil remained more similar to the degraded area. However, in the topsoil plots, we found higher macrofauna richness during rainy months and an increase in predator biomass. In conclusion, the macrofauna community in the topsoil, which has changed over time, presented higher values of morphospecies richness in some months and the increase in predator biomass, indicating an increase in the complexity of the community. Besides, the topsoil can improve biodiversity, but this does not produce the natural communities found at reference sites, in a small‐time scale experiment.

Soil Macrofauna Abundance and Taxonomic Richness under Long-Term No-Till Conservation Agriculture in a Semi-Arid Environment of South Africa

Soil macrofauna are a critical component for ecosystem function and strongly affect production sustainability. The effect of fertiliser management practices, in different cropping systems, on soil macrofauna communities remains poorly understood in semi-arid to arid regions. The objective of this study was to investigate the effect of tillage practices i.e., no-till (NT), rotational tillage (RT) and conventional tillage (CT) and nitrogen fertiliser application rates (0, 100 and 200 kg/ha N) (urea) on abundance and order diversity of soil macrofauna in a maize continuous monocropping system. The sampling of macrofauna in the trial was conducted in April 2019, August 2019 and March 2020 using 25 cm × 25 cm × 25 cm steel monoliths in randomly selected positions, and this was replicated four times. The study found a significant (p &lt; 0.05) increase in the abundance of soil macrofauna in NT (127 ind/m2) and RT (110 ind/m2) compared to CT (51 ind/m2) treatment. The abundance of macrofauna was also negatively affected by increasing the rate of fertiliser, with 0, 100 and 200 kg/ha resulting in 133, 94 and 62 ind/m2. Orders Haplotaxida and Diplopoda were found to be sensitive to increases in the fertiliser application rate. Haplotaxida (48.4%) was the most abundant order, followed by Coleoptera (18.2%). Other orders included Diplopoda (9.2%), Gastropoda (6.3%), Isoptera (4.7%), Chilopoda (4.7%), Araneae (4%), Hymenoptera (3.2%), Orthoptera (0.9%) and Dermaptera (0.3%). No-till (NT) and rotational tillage (RT) with mulch favoured the establishment of various macrofauna communities in the studied cropping system.

Land use conversion to agriculture impacts biodiversity, erosion control, and key soil properties in an Andean watershed

AbstractThe conversion of natural vegetation to agricultural land uses in mountainous Andean landscapes threatens an array of key ecological processes and ecosystem services (ES). In protected areas and buffer regions that provide water to cities, it is critical to understand how interactions between plants and soil communities sustain a range of ecosystem functions associated with nutrient recycling, soil structure, and erosion control. We sought to examine how land use conversion within a mountainous tropical forest landscape influences the diversity of vegetation and soil macrofauna communities, soil physicochemical properties, and hydrological regulation services. Biodiversity and a suite of key soil‐based ES were compared in five major land uses of the Cali River watershed: (1) annual cropping systems, (2) coffee plantations, (3) pastures, (4) abandoned shrubland, and (5) secondary forests. The diversity of woody and herbaceous vegetation, as well as soil macrofauna, was assessed in each land use. Soil chemical fertility and aggregate morphology were assessed via laboratory analyses and visual separation of soil aggregates based on their origin. Infiltration, runoff, and sediment production were measured using a portable rainfall simulator. We found a decrease in the diversity of woody vegetation across land uses to be associated with lower diversity of soil macrofauna. At the same time, agricultural management, annual crops in particular, supports the largest earthworm populations, likely due to increased organic inputs and low impact tillage, which appears not to diminish soil fertility and water infiltration. In contrast, the low soil fertility in pastures was associated with the lowest values of soil C, poor aggregation, and high bulk density and likely reflects overgrazing, with negative implications for water infiltration and erosion. Associations between the different sets of variables, evaluated with co‐inertia analysis, highlight the hierarchical relevance of plant cover and woody diversity on ES. The biological complexity associated with intact forest cover appears to generate “bundles” of co‐occurring ES, with this land use demonstrating the highest infiltration, and low runoff and sediment losses. Our findings demonstrate that forests and tree‐based agricultural systems may better contribute to the provision of multiple ES, including biodiversity conservation and hydrologic regulation.

On possible life-dispersal patterns beyond the Earth

AbstractThe assumption that exoplanets are ‘in equilibrium’ with their surroundings has not given way to life's transmissivity on large spatial scales. The spread of human diseases and the life recovery rate after mass extinctions on our planet, on the other hand, may exhibit spatial and temporal scaling as well as distribution correlations that influence the mappable range of their characteristics. We model hypothetical bio-dispersal within a single Galactic region using the stochastic infection dynamics process, which is inspired by these local properties of life dispersal on Earth. We split the population of stellar systems into different categories regarding habitability and evolved them through time using probabilistic cellular automata rules analogous to the model. As a dynamic effect, we include the existence of natural dispersal vectors (e.g. dust, asteroids) in a way that avoids assumptions about their agency (i.e. questions of existence). Moreover, by assuming that dispersal vectors have a finite velocity and range, the model includes the parameter of ‘optical depth of life spreading’. The effect of the oscillatory infection rate ($b( t,\; \, d)$) on the long-term behaviour of the dispersal flux, which adds a diffusive component to its progression, is also taken into account. The life recovery rate ($g( t,\; \, d)$) was only included in the model as a link to macrofaunal diversity data, which shows that all mass extinctions have a 10 Myr ‘speed rate’ in diversity recovery. This parameter accounts for the repopulation of empty viable niches as well as the formation of new ones, without ruling out the possibility of genuine life reemergence on other habitable worlds in the Galaxy that colossal extinctions have sterilized. All life-transmission events within the Galactic patch have thus been mapped into phase space characterized by parameters $b$ and $g$. We found that phase space is separated into subregions of long-lasting transmission, rapidly terminated transmission, and a transition region between the two. We observed that depending on the amplitude of the oscillatory life-spreading rate, life-transmission in the Galactic patch might take on different geometrical shapes (i.e. ‘waves’). Even if some host systems are uninhabited, life transmission has a certain threshold, allowing a patch to be saturated with viable material over a long period. Although stochastic fluctuations in the local density of habitable systems allow for clusters that can continuously infect one another, the spatial pattern disappears when life transmission is below the observed threshold, so that transmission process is not permanent in time. Both findings suggest that a habitable planet in a densely populated region may remain uninfected.

Diversity and abundance of soil macroinvertebrates along a contamination gradient in the Central Urals, Russia.

BackgroundSince the late 1980s, long-term monitoring of terrestrial ecosystems in metal-contaminated areas near the Middle Ural Copper Smelter has been carried out in the Central Urals. As a part of these monitoring programmes, the data on species diversity, community composition and abundance of soil macroinvertebrates continue to be gathered.New informationThe dataset (available from the GBIF network at https://www.gbif.org/dataset/61e92984-382b-4158-be6b-e391c7ed5a64) includes a 2004 census for soil macroinvertebrates of spruce-fir forests along a pollution gradient in the Central Urals. The dataset describes soil macrofauna’s abundance (the number of individuals per sample, i.e. the density) and community structure (list of supraspecific taxa, list of species for most abundant taxa and supraspecific taxa or species abundance). Seventeen sampling plots differed in the levels of toxic metal (Cu, Zn, Pb, Cd and Fe) soil contamination from air emissions of the Middle Ural Copper Smelter (heavily polluted, moderately polluted and unpolluted areas). The dataset consists of 340 sampling events (= samples corresponding to upper and lower layers of the 170 soil monoliths) and 64658 rows (2907 and 61751 for non-zero and zero density of taxa, respectively). Arachnida (Araneae and Opiliones), Carabidae (imagoes), Elateridae (larvae), Chilopoda, Diplopoda, Gastropoda, Staphylinidae (imagoes) and Lumbricidae were identified to species level. In contrast, Mermithida, Enchytraeidae, Lepidoptera larvae, Diptera larvae, Hemiptera, Hymenoptera and some other insects were identified to family or order levels. In total, 8430 individuals of soil macroinvertebrates were collected in two soil layers (organic and organic-mineral horizons), including 1046 Arachnida (spiders and harvestmen), 45 Carabidae, 300 Elateridae, 529 Myriapoda, 741 Gastropoda, 437 Staphylinidae, 623 Lumbricidae and 4709 other invertebrates. The presence-absence data on each taxon are provided for each sampling event. An overwhelming majority of such absences can be interpreted as “pseudo-absences” at the scale of sampling plots or study sites. The dataset contains information helpful for long-term ecotoxicological monitoring of forest ecosystems and contributes to studying soil macrofauna diversity in the Urals.

Macrofauna and Nematode Abundance in the Abyssal and Hadal Zones of Interconnected Deep-Sea Ecosystems in the Kuril Basin (Sea of Okhotsk) and the Kuril-Kamchatka Trench (Pacific Ocean)

The Kuril Basin and the Kuril-Kamchatka Trench are two interconnected deep-sea ecosystems both located in one of the most highly productive regions of the world’s oceans. The main distinguishing features of these deep-sea ecosystems are the low oxygen concentration in the near-bottom water in the Kuril Basin, and the high hydrostatic pressure in the trench. We investigated the abundance of meio- and macrobenthic nematodes and macrofauna on the Kuril Basin floor (depths of 3,300–3,366 m) and in the Kuril-Kamchatka Trench area (depths of 3,432–9,539 m), as well as the influence of some environmental factors on the quantitative distribution of bottom fauna. This was not studied so far. The study also focused on the species composition and quantitative distribution of Polychaeta and Bivalvia, which were dominant in abundance among macrofaunal samples. The main factors influencing the quantitative distribution of macrofauna and nematodes were depth, oxygen concentration, and structure of bottom sediments. The Kuril Basin bottom communities are characterized by a high abundance of nematodes and macrofauna, a high species richness of polychaetes, and a pronounced dominance of small-sized species of Polychaeta and Bivalvia, which are probably more tolerant to low oxygen concentrations. Compared to the Kuril Basin, the Kuril-Kamchatka Trench area (at depths of 3,432–5,741 m) had a more diverse and abundant macrofauna, and a very high abundance of meio- and macrobenthic nematodes. In the trench (at depths more than 6,000 m), the diversity of macrofauna and the abundance of macrobenthic nematodes decreased, while the abundance of macrofauna increased with increasing depth. On the trench floor, the macrofaunal abundance was highest due to the high density of populations of several bivalve and polychaete species, apparently adapted to the high hydrostatic pressure on the trench floor. Obviously, the high primary production of surface waters supports the diverse and abundant deep-sea bottom fauna in the studied areas of the northwestern Pacific. Furthermore, a large number of animals with chemosynthetic endosymbiotic bacteria were found in the bottom communities of the Kuril Basin and the Kuril-Kamchatka Trench. This suggests a significant contribution of chemosynthetic organic carbon to functioning of these deep-sea ecosystems.

Sea pens as indicators of macrofaunal communities in deep-sea sediments: Evidence from the Laurentian Channel Marine Protected Area

Pennatulacean octocorals (sea pens), one of the primary conservation targets of the Laurentian Channel Marine Protected Area (MPA) in eastern Canada, occur at high densities in some deep-sea sedimentary habitats. Considered important habitat-forming organisms for many megafaunal organisms, the effect of sea pens on nearby sedimentary macrofaunal communities remains unexplored. During two cruises in September 2017 and July 2018, we sampled 9 stations within the MPA (336-445 m depth), including sea pen fields and bare sedimentary habitats, targeting individual sea pens in a subset of the cores to assess small-scale effects. We evaluated macrofaunal density, taxonomic diversity, vertical distribution, community composition, and biological trait expression, and investigated variation between sea pen fields and other (bare) sedimentary habitats, as well as between cores with and without sea pen specimens. Using multivariate analyses, we identified abiotic and biotic drivers of macrofaunal community composition and biological trait expression. Enhancement of macrofaunal density and taxonomic diversity and higher percentages of organisms in the upper sediment layers characterized sea pen fields in autumn, with more variable results in summer. Community composition and biological trait expression consistently differed in sea pen fields compared to bare sedimentary habitats, with Pennatula sea pen density as one of the primary drivers of variation especially for community composition, along with other environmental drivers (depth, grain size, and organic matter quantity and quality). We also detected small-scale enhancement of macrofaunal diversity in cores containing sea pens at stations characterized by predominantly bare sediments. Our results indicate that macrofaunal communities within sea pen fields differ from those in bare sediments and we propose sea pens play a role in influencing those patterns by increasing food availability, stability, and small-scale heterogeneity in sedimentary habitats, acknowledging that other environmental factors might also play a role in determining the observed patterns. Characteristics of macrofaunal communities within sea pen fields also suggested potentially higher sensitivity to disturbance, which amplifies the need for protection of sea pen fields in deep-sea sedimentary environments.

Changes in the diet of the native sea urchin Arbacia dufresnii at different scenarios of the Undaria pinnatifida invasion (Patagonia, Argentina)

Undaria pinnatifida is one of the most successful marine invasive species worldwide. Since its first detection in Nuevo Gulf (Argentina), changes in the species richness and diversity of native algae and macrofauna have been reported. Knowledge of the invasive alga-native grazer interaction is key to better understand ecosystem dynamics and the potential effects of Undaria on local food webs. The aim of this study was to compare the diet of the sea urchin Arbacia dufresnii, among different scenarios of invasion of Undaria in two northern Patagonian gulfs. To this end, we determined the relative contribution of kelp to the diet of the sea urchin by comparing the gut content and stable isotopes in different tissues of A. dufresnii from sites where the invasion of Undaria was advanced, relatively recent, or not recorded. Because A. dufresnii has a plastic feeding habit and Undaria represents a high input of algal biomass, our hypothesis was that A. dufresnii feeds on Undaria and that the contribution of the invasive kelp to the diet of the sea urchin will be greater according to the time elapsed since invasion. Our results confirmed that A. dufresnii fed on Undaria and assimilated in gonads and muscle. The contribution of Undaria to the sea urchin diet was related to the stage of invasion. In the site with an advanced stage of invasion, A. dufresnii consumed the kelp both in spring and summer, when sporophytes were mature and senescent, respectively. However, in the recently invaded site, A. dufresnii consumed Undaria only in summer, when the kelp was senescent. Arbacia dufresnii is an omnivore species with the plasticity to adapt its diet to a variety of resources depending on the availability in the environment, prioritizing faunal items. This work reinforces the importance of complementing gut analysis with stable isotope analysis to determine the contribution of items in the diet. Although the impacts of an invasive alga on food webs and ecosystem structure are difficult to evaluate, performing these analyses in different scenarios may allow better understanding the local food web structure and assessing the possible ecological consequences over the invaded habitat.

Changes in Biomass and Diversity of Soil Macrofauna along a Climatic Gradient in European Boreal Forests.

Simple SummaryWe used a 1000 km long latitudinal gradient in north-western Russia to study the potential impacts of a changing climate on soil invertebrates visible by a naked eye (insects, spiders, earthworms etc.). We extracted these animals from soil, weighed them and identified them to the species level. We found that the diversity of soil invertebrates decreased towards the north, whereas the latitudinal pattern in biomass depended on the animal’s feeding habit. The biomass of species feeding on live plant roots and fungal mycelia decreased towards the north, whereas the biomass of species feeding on dead plant tissues and live invertebrates showed no significant latitudinal changes. The discovery of this variation in latitudinal biomass patterns suggests that soil invertebrates from different feeding guilds may respond differently to climate change. As a result, the biomass ratio between consumers and their food resources (e.g., herbivores and plants, predators and prey) may change. We poorly understood how this change will affect the future structure and functions of boreal forest ecosystems.Latitudinal gradients allow insights into the factors that shape ecosystem structure and delimit ecosystem processes, particularly climate. We asked whether the biomass and diversity of soil macrofauna in boreal forests change systematically along a latitudinal gradient spanning from 60° N to 69° N. Invertebrates (3697 individuals) were extracted from 400 soil samples (20 × 20 cm, 30 cm depth) collected at ten sites in 2015–2016 and then weighed and identified. We discovered 265 species living in soil and on the soil surface; their average density was 0.486 g d·w·m−2. The species-level diversity decreased from low to high latitudes. The biomass of soil macrofauna showed no latitudinal changes in early summer but decreased towards the north in late summer. This variation among study sites was associated with the decrease in mean annual temperature by ca 5 °C and with variation in fine root biomass. The biomass of herbivores and fungivores decreased towards the north, whereas the biomass of detritivores and predators showed no significant latitudinal changes. This variation in latitudinal biomass patterns among the soil macrofauna feeding guilds suggests that these guilds may respond differently to climate change, with poorly understood consequences for ecosystem structure and functions.

Macrofaunal Distribution, Diversity, and Its Ecological Interaction at the Cold Seep Site of Krishna-Godavari Basin, East Coast of India.

Cold seeps are characterized by typical endemic communities with associated microorganisms that depend on sulfide, methane, reduced nitrogenous compounds, and metals as electron donors for their survival through chemosynthesis. The discovery of an active cold seep site in January 2018 in the Krishna-Godavari (K-G) basin of Bay of Bengal was followed by a transit cruise in March 2018 to investigate the distribution and diversity of macrofauna. Further, the ambient sediment and pore water biochemistry were estimated to understand its relationship with macrofauna and the microbial associates of the sediment. Samples were collected at a water depth of around 1750m at 3 stations: SP1, SP2, and SP3, using the box corer. The benthic fauna at the sites consisted mainly of Bivalvia, shrimps of Caridea family, Gastropoda species, Malacostraca species, Polychaeta, and few species of Echinoidea, Ophiuroidea, and Echiura. A total of 2313 macrofaunal individuals belonging to 8 classes, 18 families, and 20 species were identified from all the three stations. The communities were diverse at these sites with an average Shannon diversity index of 1.64 and are closely related to the lineages previously studied in ecologically similar environments. Most of the macrofauna were found to be filter feeders preferring a low organic carbon environment. Relict vesicomyid clams at the present study site suggest the succession from vesicomyids to the present composition of bivalve mussels and siboglinid worms. The microbial associates in the sediment significantly correlated with methane and hydrogen sulfide concentrations. The study suggests that the K-G basin cold seep serves as a conducive environment for the flourishing of benthic communities and therefore can support a rich biodiversity.