Macrofaunal Diversity Research Articles

Deep-ocean macrofaunal assemblages on ferromanganese and phosphorite-rich substrates in the Southern California Borderland.

Mineral-rich hardgrounds, such as ferromanganese (FeMn) crusts and phosphorites, occur on seamounts and continental margins, gaining attention for their resource potential due to their enrichment in valuable metals in some regions. This study focuses on the Southern California Borderland (SCB), an area characterized by uneven and heterogeneous topography featuring FeMn crusts, phosphorites, basalt, and sedimentary rocks that occur at varying depths and are exposed to a range of oxygen concentrations. Due to its heterogeneity, this region serves as an optimal setting for investigating the relationship between mineral-rich hardgrounds and benthic fauna. This study characterizes the density, diversity, and community composition of macrofauna (>300 μm) on hardgrounds as a function of substrate type and environment (depth and oxygen ranges). Rocks and their macrofauna were sampled quantitatively using remotely operated vehicles (ROVs) during expeditions in 2020 and 2021 at depths above, within, and below the oxygen minimum zone (OMZ). A total of 3,555 macrofauna individuals were counted and 416 different morphospecies (excluding encrusting bryozoans and hydrozoans) were identified from 82 rocks at depths between 231 and 2,688 m. Average density for SCB macrofauna was 11.08 ± 0.87 ind. 200 cm-2 and mean Shannon-Wiener diversity per rock (H'[loge]) was 2.22 ± 0.07. A relationship was found between substrate type and macrofaunal communities. Phosphorite rocks had the highest H' of the four substrates compared on a per-rock basis. However, when samples were pooled by substrate, FeMn crusts had the highest H' and rarefaction diversity. Of all the environmental variables examined, water depth explained the largest variance in macrofaunal community composition. Macrofaunal density and diversity values were similar at sites within and outside the OMZ. This study is the first to analyze the macrofaunal communities of mineral-rich hardgrounds in the SCB, which support deep-ocean biodiversity by acting as specialized substrates for macrofaunal communities. Understanding the intricate relationships between macrofaunal assemblages and mineral-rich substrates may inform effects from environmental disruptions associated with deep-seabed mining or climate change. The findings contribute baseline information useful for effective conservation and management of the SCB and will support scientists in monitoring changes in these communities due to environmental disturbance or human impact in the future.

Assessment of nutrient status, macro faunal diversity and microbial isolates in date palm plantation in Damaturu Yobe State, Nigeria

This research assessed nutrient status, macro-faunal diversity and microbial isolates in the soil of date palm plantation in Mai Sandari Damaturu, Yobe State. Parameters evaluated include; data on nutrient status of soils, assemblage and diversity of soil macro invertebrates and assemblage of microbial isolates based on growth performances of the date palm. The plantation was divided according to growth variabilities. Eighteen (18) auger points were taken, six (6) in each performance site based on the corresponding variability as observed. Soil samples were collected within same points for physicochemical analysis, microbial isolates and for soil macro-invertebrates ‘identification and enumeration. One-way Analysis of Variance (ANOVA) was used to compare results of nutrient status of soils and to test for significant differences in nutrient concentration of the soils samples, mean separation was done using Least Significant Difference (LSD). Soil macro-invertebrate assemblage was analyzed for diversity indices of species using relevant formulae. Nutrient agar medium at 105 dilutions inoculated in a petri-dishes and incubated at 30±10°C for 2-5 days for bacteria colonies, while for fungi and actinomycetes, sabaurond dextrose agar was used at 25°C for 5-7 days and afterward microorganisms per colony forming units (Cfu) were counted. Analysis of variance for the soil parameters tested at p≤ 0.05 level of significance showed no significant differences in all the parameters of soil physical properties based on growth performance sites. However, organic carbon, organic matter and TN vary significantly after the post-hoc tests across growth performance sites in chemical properties (p ≤ 0.05). Results showed a total of 2646 macro fauna scattered within the study area. Eleven (11) families of macro fauna were also identified in the study. Results from the study area showed that the area is highly rich in microorganisms. A total of 5096 colonies were scattered within 10 families in the study area. The finding of this study revealed that there was no significant difference among the physical properties across the study site leading to the conclusion that soil physical properties may not have been responsible for the observed differences in the growth of the Date Palm Plantation. A different pattern was however observed in the values of the chemical properties of the plantation where significant differences exist in organic carbon, organic matter and total nitrogen across these sites. Based on the findings of the study it is recommended that all application of agrochemicals except fertilizers in the plantation should be suspended until evidence of their efficiency on the palm trees is shown.

How restoration engineering measures can enhance the ecological value of intertidal flats

Restoration engineering measures, such as managed realignments or building groins, modify the environmental characteristics of coastal intertidal ecosystems. Creating physical modifications that are beneficial to an intertidal system's ecology necessitates an in‐depth understanding of the relationships between the abiotic and biotic components of a given intertidal habitat. In this study, we evaluate how hydrodynamics and sediment characteristics drive the development of the benthic macrofauna community during the first 5 years following engineering measures to enhance benthic macrofauna diversity at three locations. The creation of low‐energy habitats through groins (Knuitershoek and Baalhoek) and a managed realignment dike breach (Perkpolder) led to the accumulation of fine sediments in all three impact sites. Biomass of benthic macrofauna quickly increased between 2016 and 2020, with successional processes being more important in Perkpolder, where the habitat was started completely from scratch due to a managed realignment, than at Knuitershoek or Baalhoek, where habitat conditions were improved by adding groins. In addition, the density of benthos‐eating birds, especially oystercatchers, increased at some of the modified sites. While a low‐energy habitat may harbor more diverse assemblages of benthic macrofauna than a highly dynamic one, the extremely high silt content, which is typical for low‐energy habitats, may slow benthic community development. The observed increase of biomass at our impact sites highlights the value of the interventions, while the delays in the response of the benthic macrofauna community emphasizes the need for extensive monitoring both in time and space and the identification of underlying abiotic–biotic mechanisms.

Diversity, distribution and knowledge gaps of Polychaeta on the continental shelf of southern Namibia

This study investigated the diversity, composition and distribution patterns of polychaete macrofauna inhabiting unconsolidated sediments on the continental shelf of southern Namibia. During the austral summer of 2021, 910 Van Veen grab samples were collected from 91 sites in water depths ranging between 43 and 146 m. All benthic macrofauna (> 1 mm) were extracted, identified, enumerated and weighed. Polychaetes were the most abundant taxon, equating to 66% of total abundance and 37% of total biomass. A total of 83 712 polychaete specimens comprising 112 species, 80 genera and 33 families were collected. Several taxa identified were listed as putative cosmopolitans (19 taxa) or have known wide local distributions (10 taxa). Voucher specimens were collected for DNA barcoding to improve reference sequence libraries for the region. Hierarchical cluster analyses using both abundance and biomass data were undertaken to determine spatial distribution patterns in polychaete communities. Both datasets yielded similar results with polychaete assemblages divided into inshore and offshore communities, that were further subdivided at a local scale. Investigation of physical and chemical drivers suggested that polychaete communities in southern Namibia are structured to varying degrees by water depth, latitude, sediment composition, redox potential and organic content. Deeper stations comprised the highest diversity of polychaeta fauna. Species adapted to hypoxic conditions (e.g. Sigambra parva, Pararionospio pinnata, Diopatra cf. monroi and Nepthys cf. hombergii) dominated an area known as the mudbelt, where organically enriched silts and clays originating from the Orange River are deposited on the mid-shelf between the 40 and 120 m isobaths.

Трансформация почвенных зооценозов в первый год после рубки леса

Soil macrofauna of primary forests of the middle taiga is characterized by high abundance (94.6–146.6 ind./m2), taxonomic richness (10–14 taxa), dominance of Diptera and Cantharidae larvae, similarity of fauna composition (J=0.60–0.65), with a ratio of detritivores and predators equal to 1:1, aggregated or random horizontal distribution. The total density of invertebrates sharply decreases (4.5–26.8 ind./m2) in the first year after deforestation. Some taxa are eliminated from the fauna, 4–7 taxa are remained. The ratio of trophic groups is changed. The distribution of invertebrates in space is disturbed. Soil macrofauna of clear-cutting areas (CCA) retains a taxonomic structure close to the control sites (C). The taxonomic and trophic structure of soil macrofauna is more disturbed on the logging corridors (LC) with three (3LC) and ten (10LC) penetrations of aggregate equipment, recultivated (RLC) and main (MLC) logging corridors. Thus, the density of Diptera larvae is high on the logging corridors. The above are temporary r-strategists characteristic for the disturbed environment. And the ratio of detritivores and predators on the technological sites “C – CCA – 3LC – 10LС – RLC – MLC” is 1:1 – 3:1 – 7:1 – 10:1 – 13:1 – 15:1. A trend towards an increase in the density of detritivores on the recultivated (RLC) and main (MLC) logging corridors was noted. The decrease of the total density of macrofauna and the declining of systematic groups of the clear-cutting areas is not so significant due to the fact that the litter on these sites is almost completely preserved after felling. The low diversity of soil macrofauna on the logging corridors can be explained by a change in the natural conditions for the existence of invertebrates due to the compaction of the upper soil horizons, the partial disappearance of the litter, the appearance of a mineralized soil layer as top horizon, and a rapid change in humidity. Significant changes in the abundance, composition, and ratio of trophic groups of invertebrates indicate the collapse of soil macrofauna, the loss of important groups of destructors and predators from food webs, and a decrease in the quality of their functions at the initial stage of restorative succession, in the first year after deforestation.

A complex relationship between cropping systems and soil macrofauna: Influence of practice intensity, taxa and traits

Larger soil organisms have often been reported as the most sensitive to disturbances caused by cropping practices. However, soil macrofauna comprises groups with a wide diversity of morphological and ecological features, which may respond differently to applied practices. In order to further assess the effect of cropping systems on soil macrofauna, macrofauna organisms were extracted from soil blocks over 21 fields (each comprising three plots) located in the Paris basin, in autumns 2020 and 2021. Fields belonged to conventional, conservation or organic systems, either long-established (≥ 7 years) or in transition (≤ 3 years). Tillage, pesticide treatment and organic matter input intensity were assessed in each field using composite indexes of practice intensity. Macrofauna density and diversity, earthworm ecological categories, species richness and functional traits were investigated. Our results showed that the density and diversity of macrofauna demonstrated few differences regarding different cropping systems, with highly variable effects across groups and years. Specific macroarthropod groups responded differently to tillage, pesticide treatment and organic input intensity, but not over the two years of the study. Regarding earthworms, high tillage intensity had a negative effect on the density and biomass of epi-anecic juveniles and on species with a small body size. Higher organic matter inputs had a negative effect on the density and biomass of endogeic earthworms, and could be related to several earthworm functional traits (body length, mass/length ratio, carbon preferences). Effects of pesticide treatments were less clear, although they could have impacted some earthworm species. More generally, taxonomic and functional trait approaches of earthworm community led to similar conclusions. Overall, our results support the need to account for (i) the actual intensity of practices in cropping systems and (ii) the different taxonomic, trophic and ecological groups of macrofauna, in order to assess the effects of cropping systems on soil biodiversity.

Diversity of functional edaphic macrofauna in Musa acuminata x Musa balbisiana (AAB) agroecosystems

Background This study focused on evaluating the diversity and richness of the edaphic macrofauna in eight banana farms in the western zone of Nicaragua. Methods The sampling design was random and descriptive, it was divided into two phases, the first was the collection of the sample, and the second was the classification, coding, and storage of the extracted macrofauna populations. The sampling method employed included the extraction of soil and litter samples. Soil samples were collected using a wooden frame (monolith), with each sample weighing approximately 1 kilogram and taken from a depth of 0.20 cm. Litter samples were collected from the soil surface. A total of 80 samples were collected, with 40 soil samples and 50 litter samples obtained across the 8 plantain farms. Results The results showed that the relative abundance of biodiversity was higher in the 0–20 cm soil depth stratum than in the branch and leaf biomass strata. The values of the diversity indices of Simpson's Dominance, Shanon, Margalef, and Equity were in the normal range, with a tendency towards low diversity. Likewise, in the richness of species, the Dominance or most abundant genus were earthworms (Oligochaeta) and Hymenoptera (Solenopsis, Leptothorax, Camponotus, Pheidole), indicating the directly proportional relationship, that is to say, that the greater the number of earthworms the production increases and the greater the number of Hymenoptera it decreases, confirmed with the Pearson correlation coefficient with a reliability of 95%. Conclusions It was concluded that based on the estimates of the diversity indicators, two detritivore genus (earthworms and Hymenoptera) were the ones with the more dominance, being important in the production of the banana agrosystem due to the decomposition of organic matter and its nutritional contribution to the plant. We observed a direct correlation with earthworms and an indirect relationship with Hymenoptera.

Soil macrofauna diversity and biomass associated with the “fertility islands” beneath oak trees in a semi-arid woodland

Fertility islands are patches of soil beneath the trees and shrub's canopy and contain higher nutrient availability and water content than the surrounding areas in arid and semi-arid lands. Fertility islands are home to various soil organisms that play a crucial role in nutrient cycling. This study aimed to determine the influence of fertility islands beneath the coppiced oak trees on soil macrofauna diversity and biomass in semi-arid oak woodland. For this purpose, two main microhabitats, including beneath the patches of oak sprout-clumps (BPSC) and the interspaces (SBSC), were considered. Each microhabitat was divided into four classes with respect to the number of sprouts per sprout-clumps (N = 1–3, N = 3–10, N = 10–20, and N > 20) and distance gradient from the canopy (D = 0 m, D = 1–3 m, D = 3–5 m, and D > 5 m). Soil physical and chemical properties, soil macrofauna taxonomic group diversity, and biomass were measured for each microhabitat class. Most of the soil's physical and chemical properties, such as soil litter, soil organic carbon (SOC), available phosphorus (P), moisture content, and electrical conductivity (EC), were higher in BPSC than in SBSC. These properties were influenced by the structure (number of sprouts) of oak sprout-clumps and the distance gradient from the canopy. Soil macrofauna individuals (density), biomass, and diversity were higher in BPSC than in SBSC. A significant difference in soil macrofauna groups composition was found only at the canopy edge and was not affected by increasing distance from the canopy. The soil macrofauna diversity was positively correlated with soil moisture, SOC, and P. It was concluded that the sprout-clumps' structure influences the quality of fertility islands beneath the oak sprout-clumps and consequently dictates the variation of soil macrofauna composition and biomass.

Functional diversity of benthic macrofauna during and after an el niño event in a subtropical estuary

Bioturbation promoted by benthic macrofauna impacts the biogeochemical processes in the sediment and water column, being an important process in estuaries, which are depositional ecosystems of high ecological importance. Functional diversity provides clear connections between biota and environmental variables, enabling researchers to comprehend the structure and functioning of ecosystems. The functional approach is still an emerging field of studies for estuaries, especially in the context of weather events such as the ENSO – El Niño. We investigated the functional diversity on a sandflat in the Patos Lagoon Estuary, regarding the bioturbation related traits of the benthic macrofauna, during and following the 2002/2003 El Niño event. Our study evidenced that the decrease in salinity caused by the high precipitation during the El Niño was the most influential factor affecting the functional diversity of the macrofauna. This led to assemblages with less potential for bioturbation, decreased stability, and higher prevalence of opportunistic traits. We also found that despite using bioturbation related traits for our analysis, the proportions of sand, silt, and clay in the sediment were not the main drivers of changes in the functional indices or trait composition, presenting less influence than the seasonal variation of temperature.

Diversity of soil macrofauna in traditional oil mining of Wonocolo Geosite, Bojonegoro Geopark, East Java, Indonesia

Abstract. Rahmawati LA, Afiati N, Putranto TT. 2024. Diversity of soil macrofauna in traditional oil mining of Wonocolo Geosite, Bojonegoro Geopark, East Java, Indonesia. Biodiversitas 25: 2148-2160. Wonocolo traditional oil mining has been going on for 130 years and has led to soil pollution. This study aims to characterize the composition of macrofauna in the soil affected by Wonocolo's traditional oil mining. The existence of macrofauna is important as a bioindicator of soil quality and its role in maintaining soil fertility levels. Mining areas are grouped based on the density of the oil well (rare, medium and dense), then three sample points are selected in each group. Macrofauna were collected using quadrat-hand sorting, pitfall trap, and flannel trap methods, and then the community structure index was analyzed. The results showed that 709 individuals were collected consisting of 17 orders and 71 species, with 64.8% of individuals found in category-dense areas. Hymenoptera and Polyrhachis sp. as the most abundant order and genus, while Odontomachus brunneus Patton 1894 is the most frequently encountered species. The average value of biodiversity, dominance, and evenness index ranged H'=1.28-1.57 (low), C=0.29-0.38 (low), and E=0.78-0.90 (high), respectively. Indications of environmental conditions in traditional oil mining areas cannot be seen solely from the value of the macrofauna biodiversity index but are apparent in the abundance of the Hymenoptera order in all areas categories and significant presence of Polyrhachis sp. species in the dense category.

Diversity and Abundance of Soil Macrofauna in Wheat Fields with Low and High Input of Fertilizers

Diversity and Abundance of Soil Macrofauna in Wheat Fields with Low and High Input of Fertilizers

The relation of macrofauna and soil organic carbon in Sacha Inchi cropping patterns

Abstract Soil macrofauna plays an important role in the soil ecosystem. Through various biological activities, macrofauna provides various ecosystem services such as the provision and regulation of nutrients and carbon through litter decomposition, increasing water holding capacity, and improving soil structure. The diversity of soil macrofauna is strongly influenced by the litter produced. The more diverse types of plants, the more diverse macrofauna will be found. The purpose of this study was to determine the relationship between macrofauna and soil organic carbon in various cropping patterns of sacha inchi in Sragen, Central Java. The research was conducted on teak-sacha inchi, teak monoculture, mixed agroforestry, and sacha inchi monoculture. Based on the results, there were a total of 6 orders of macrofauna in four types of cropping patterns. The highest total number of individuals was found in the sacha inchi monoculture. The macrofauna diversity index was found the highest in teak-sacha inchi with a Shannon-Wiener index of 1.207, and the lowest in the sacha inchi monoculture with a Shannon-Wiener index of 0.76. Based on the correlation analysis, it is known that soil organic carbon content has a negative correlation with the number of macrofauna and a positive correlation with macrofauna diversity.

Distribution of Soil Macrofauna Diversity and Abudance Land Used at Moving Agricultura Systems Warmare District, Regency of Manokwari, Province of West Papua

Warmare District, Manokwari Regency, West Papua Province is one of the areas where the people still maintain the shifting cultivation system and it has even become one of the local wisdoms in the area. This research aims to examine the diversity and density of soil macrofauna on shifting cultivation land in the Warmare District, Manokwari Regency. The method used in this research is the direct handsorting method in the field and macrofauna identification using a binocular microscope. Data analysis used in this research was cluster analysis with PAST (Powerful Software for Scientific Data Analysis) software version 3.4 and used the Landmarks 3D PCA test to see the relationship between soil macrofauna diversity and land use types. The research results showed that the highest density and diversity of soil macrofauna was shown by the use of forest land with 38 taxa at a depth of 0-10 cm and 37 taxa at a depth of 10-20 cm. Where the high diversity composition of the Shannon-Weaner index is shown by forest land use with a value of 0.94 and is reinforced by the low Simpson index value of 0.30 for forest land use. This is in line with the results of the PCA analysis which shows that macrofauna forest land is compared with monoculture cultivation land and polyculture cultivation land.

Variations of the soil macrofauna community and corresponding influencing factors in the newly reclaimed coastal area: A case study in Yangtze Estuary, China

Intensive reclamation activity has reshaped global coastal ecosystems. Soil macrofauna, an effective proxy for ecosystem health, has the potential to predict coastal reclamation ecological impact. Previous studies have primarily focused on the long-term (≥ 30 years) soil macrofaunal succession in reclaimed areas. However, composition of the soil macrofauna and its environmental drivers in newly reclaimed areas (< 30 years) remain uncertain. We selected Hengsha Dongtan in the Yangtze Estuary to conduct the study, and four different regions (reclaimed for 13, 8, 4, and 1 year, respectively) were employed to investigate soil macrofaunal composition and corresponding environmental drivers. The results showed that: (1) Terrestrial species millipedes (Paradoxosomatidae sp.), chinch bugs (Dimorphopterus spinolae), and wolf spiders (Pirata subpiraticus) were dominant. Millipedes, chinch bugs, wolf spiders, ants (Myrmecina sp.), and rove beetles (Stenus melanarius and Paederus fuscipes) were major species contributing to the average dissimilarity among regions. (2) The taxonomic composition of soil macrofauna varied over time after reclamation, which showed that the number of species, density, and biomass of soil macrofauna in region 1 (reclaimed for 13 years) was higher than that in regions 2, 3, and 4 (reclaimed for 8, 4, and 1 year). (3) The functional composition of soil macrofauna varied over time after reclamation. The number of species, density, and biomass of the phytophagous and saprophagous groups increased over time, whereas those of the predatory group decreased gradually. (4) Soil pH and total organic carbon content, together with land use, appeared to be key factors that determine soil macrofaunal composition. Overall, our study illustrates the response of soil macrofauna to changes in environmental factors and land use in newly reclaimed areas. Future studies should expand the range of potential factors and comprehensively analyze the mechanisms that maintain soil macrofaunal diversity in reclaimed areas.

Macrofaunal diversity patterns in coastal marine sediments: re-examining common metrics and methods

Complex biodiversity patterns arise in marine systems due to overlapping ecological processes, including organism interactions, resource distribution, and environmental conditions. Despite the importance of documenting these patterns, describing diversity in natural ecosystems remains challenging. Here, we investigate 3 nearshore sub-Arctic sites to describe benthic macroinfaunal taxa and biological traits, with the ultimate aim of determining whether common diversity metrics and typical sampling efforts adequately capture community composition in these systems. First, we assess how diversity relates to sediment depth and examine relationships among commonly used taxonomic and functional diversity indices. Second, using a power analysis, we explore how sampling effort influences the interpretation of diversity patterns in coastal systems. We report significant variation in community composition among sites, even across small spatial scales of km, and find that taxonomically diverse communities do not necessarily correspond to high functional diversity. We further find that although environmental factors such as sediment depth consistently affect macroinfaunal diversity, the direction and magnitude of these relationships are site-dependent. Finally, we demonstrate that typical sampling effort for coastal benthic studies (for example, &lt;5 push cores of ~7 cm diameter) may not capture macroinfaunal community composition adequately, potentially obscuring hotspots in common diversity metrics such as taxonomic or functional richness. However, indices such as Simpson’s diversity may be well-suited to resource-limited studies with restricted sampling capacity. Our results highlight the importance of adopting multi-pronged approaches to biodiversity assessment and determining optimal sample sizes for marine benthic systems, particularly in the context of biodiversity monitoring for conservation purposes.

Ecological patterns of intertidal macrofauna across an anthropic gradient on tropical Gulf of Mexico sandy beaches: Insights for assessment

In the context of sandy coastlines under increasing coastal development and squeeze, coupled with the ongoing loss of global diversity, it is crucial to understand the ecological patterns of benthic macrofauna, which plays a key role in the trophic and biogeochemical functional connectivity between land and sea. Here, we assessed differences in the spatiotemporal patterns of macrofauna diversity and production in exposed sandy beaches of the southwestern Gulf of Mexico across a use and modification gradient and its utility as indicators of impacts. We also estimated the sampling effort for a representative species inventory, considering three tidal zones, and longitudinal spatial scales in four beaches twice a year, and locally after an event of great tourist incidence. The traditional diversity indices could not conclusively detect the stress gradient of the macrofauna in these systems. The abundance pattern of macrofauna species in the upper intertidal zone and the greater secondary production at the lower zone of the unmodified beaches could be useful as indicators of ecological integrity in natural beaches with similar morphodynamic conditions. On the contrary, the most disturbed beach exhibited greater instability in terms of its macrofauna temporal variation in the lower zone. We verified that the ecological integrity approach comprising both natural and anthropogenic factors and multiple stressors is a useful tool showing precisely how beach-intensive use and modification induce instability and less resilience of its macrofauna, reflected in the species' distribution by tidal zones, and the secondary production patterns. We also provide the first estimate of the optimal sampling effort required to get a representative inventory of the benthic intertidal macrofauna in sandy beaches of the Western Gulf of Mexico within a gradient.

Environmental drivers of biogeography and community structure in a Mid-Atlantic estuary

Estuaries include some of the most productive yet anthropogenically impacted marine ecosystems on the planet, and provide critical habitat to many ecologically and economically important marine species. In order to elucidate ecological function in estuaries, we must understand what factors drive community dynamics. Delaware Bay is the third largest estuary in the United States and hosts over 200 species of migrant and resident fishes and invertebrates. The Delaware Division of Fish and Wildlife has conducted two long-term trawl surveys at monthly intervals in Delaware Bay since 1966. The two surveys collect data on environmental conditions, species composition, and number of fishes and macroinvertebrates across different size classes and life histories. Using a suite of multivariate approaches including hierarchical cluster analysis, canonical correlation analysis, and permutational multivariate analysis of variance, we characterized the fish and macroinvertebrate community in Delaware Bay and found that community composition and environmental conditions varied across spatial and seasonal scales. We identified four distinct biogeographic regions, based on environmental conditions and community composition, which were consistent across surveys. We found that the community was driven primarily by gradients in temperature and salinity and that abundant, frequently occurring species in the Bay have well-defined environmental associations. Our work represents the first attempt to use an existing historical survey to better understand how environmental parameters influence diversity and distribution of macrofauna within Delaware Bay, providing insight into how abiotic variables, influenced by climate, may impact the Delaware Bay ecosystem and similar estuarine ecosystems worldwide.

Quantifying the direct and indirect relationships linking the environment, seagrass, and their associated fauna

AbstractFoundation species such as seagrasses modulate critical ecosystem processes, promote biodiversity, and structure community spatial and temporal dynamics. Hence, they play a key role in mediating the response of biodiversity to environmental changes. The breadth of their contribution to biodiversity maintenance and the potential cascading effects of their alteration remain unclear as we lack a comprehensive understanding of the intricate mechanisms governing their response to environmental changes and that of their associated fauna. Indeed, the mechanisms involved are often studied in isolation or at scales that only provide incomplete representations of the complex functioning of these ecosystems. This study aimed to clarify the direct and indirect relationships linking the environment, seagrass, and their associated faunal assemblages, using structural equation modeling (SEM). To this end, we review the literature to derive theoretical models of the functioning of seagrass ecosystems and test them using long‐term monitoring data covering 14 years of nine different Zostera marina seagrass beds across 500 km of coastline. We show that contradictory relationships and ambiguities regarding seagrass–biodiversity relationships emerge from the currently available literature (covering experimental, observational, and modeling studies). The SEM approach allowed us to clarify these direct and indirect relationships and resolve most ambiguities. In particular, we show that seagrass mediates the effect of the environment on its associated communities. However, this mediating effect is different, both qualitatively and quantitatively, for epifauna and infauna. Unexpectedly, the diversity of benthic macrofauna appeared to be controlled and promoted by the biomass rather than by the shoot density of the seagrass beds. We also provide quantitative estimates for the direct and cascading pathways linking seagrass biodiversity to environmental changes. Overall, by synthesizing, clarifying, and quantifying the multiple relationships linking a foundation species such as seagrass to its environment and associated biodiversity, we contribute to a better understanding of seagrass meadows functioning and help predict the potential consequences of foundation species alteration on their associated fauna.

Structural attributes and macrofaunal assemblages associated with rose gorgonian gardens (Leptogorgia sp. nov.) in Central Chile: opening the door for conservation actions

Gorgonians (like corals) are important habitat-forming organisms that support a diversity of macrofauna. This study explored structural attributes of gorgonian gardens formed by rose gorgonians (Leptogorgia sp. nov.) and associated macrofaunal assemblages in Caleta Pichicuy (Central Chile). Hierarchical sampling was conducted at 20 m depth (maximum colony abundances) in order to assess spatial variability in abundance and colony attributes at two spatial scales (among sites and rocky walls). The abundance and composition of the associated vagile and sessile macrofauna were also examined using univariant (Taxa richness and Shannon index (H’e)) and multivariant approaches and were compared with adjacent bare rocky habitats. Our results showed a high abundance of gorgonians (ca. 28.9–36.5 colonies m−2) compared to other gorgonian gardens in the world. For structural attributes, our results showed smaller colonies with thicker holdfasts in more exposed sites, suggesting the influence of hydrodynamic forces on the colony morphology. Taxa richness and H’e of vagile fauna showed threefold and twofold, respectively, higher values in gorgonian gardens compared to bare walls, but no differences were observed for sessile fauna. In addition, PCoA and PERMANOVA evidenced a distinctive assemblages’ composition between habitats for both vagile and sessile fauna. Correlation analyzes and dbRDA showed, however, little association between structural attributes and associated faunal assemblages (R2 = 0.06, and ca. 3–9.4% of the total variation explained, respectively). Our results constitute the first assessment of structural habitat complexity and accompanying fauna in these gorgonian gardens and establish the baseline for understanding possible future changes associated to human activities.

Edaphic Macrofauna in Areas Cultivated with Irrigated Brassica Under No-Tillage System

Objective: Quantify and qualify the soil macrofauna present in areas cultivated with brassicas under the No-till system vegetable (NTSV) in different phases. Method/design/approach: The study was conducted in three different areas: 1-NTSV with one year (NTSV1), 2-NTSV with three years (NTSV3), 3-Native Forest (In natural regeneration for 20 years (NF20)); At depths: 0-10; 10-20 and 20-30 cm, with 5 repetitions. Litter was collected in an area of 0.50x0.50 cm and soil samples were collected with an iron square measuring 25x25x30 cm in each plot, where the number of individuals (ind m-2) was quantified and the total richness and diversity and equitability indexes of the macrofauna were qualified. Result and conclusion: The management in areas NTSV1, NTSV3 and NF20 favored the development of the population of the Formicidae and Isoptera groups; The NTSV3 area at a depth of 20 to 30 cm provided the best conditions for the highest relative frequency of the Oligochaeta group. Research implications: The assessment of vertical distribution favored a broader knowledge of the macrofauna community in the systems; The adoption time of the one- or three-cycle no-tillage system did not affect the density and diversity of macrofauna. Originality/value: Most studies soil macrofauna have been carried out in areas under conventional or no-tillage of grains or in forests, few studies are carried out in areas with irrigated vegetables, where processes involving organic matter reach be three times faster, where the diversity of this macrofauna is higher and needs to be evaluated.