Macrofaunal Diversity Research Articles

Monitoring of The Palm Oil Plantation Ecosystem Based on Land Macrofauna Diversity

Oil palm plantations of PT. Supra Matra Abadi has used palm oil mill effluent to the plantation area as fertilizer (Land Application) to part of its plantation area. The difference in land use and management in the plantation area also determines the presence, both species, density, diversity index value, and soil macrofauna uniformity index. Soil macrofauna plays a role in maintaining the balance of the soil ecosystem. This research has been conducted at PT. Supra Matra Abadi, located in Kebun Panji Bay, Kampung Rakyat District, Labuhanbatu Selatan Regency, North Sumatra Province in May-July 2018. This research was conducted to determine the presence of species, population density, diversity index values, and uniformity of soil macrofauna on oil palm plantations. Determination of the sampling point is done by the Purposive Random Sampling method, soil macrofauna sampling using the Quadratic and Hand Sorting methods. There are 15 species of soil macrofauna which are grouped into 2 phyla, 5 classes, 9 orders, 12 families, and 15 genera. The highest density value was found in the area of plantations that were not given liquid palm oil mill effluent as fertilizer (Non Land Application) of 282.15 ind / m2 and the highest diversity index value was found in the area of oil palm plantations which were fertilized with palm oil mill liquid waste to land area (Land Application) which shows that the condition of the oil palm plantation ecosystem which is fertilized with palm oil mill effluent (Land Application) can support the life, diversity, and uniformity of soil macrofauna.

Keanekaragaman dan Kelimpahan Makrofauna Tanah pada Tiga Tegakan Berbeda di Hutan Pendidikan Gunung Walat

Soil macrofauna is an important factor in studying the biological soil quality. The activity of soil macrofauna affects the soil properties and condition. The objective of this study was to identify the soil macrofauna and analyze the diversity, evenness, and richness index of soil macrofauna on some sites at educational forest of gunung Walat. The macrofauna was collected using hand sorting method on 40x40 cm plots in 10 cm depth of soil and 3-5 cm thick of forest litters at Agathis, Pinus, and Puspa trees. The identification result showed that a total 641 individuals were found under Agathis, Pinus, and Puspa trees. The Pinus trees showed the highest frequency of soil macrofauna (377 individu). The Agathis trees showed the highest value of diversity index, that was H’=2.38, DMg=4.12, and E=0.78.
 Keywords: abundance, diversity, soil macrofauna, hand sorting method, Gunung Walat

Variables que afectan a la diversidad de organismos del suelo en zonas verdes de la ciudad de Donostia-San Sebastián

Epelde, L., Salazar, O., Martín, I., Garbisu, C. 2020. Variables affecting the diversity of soil organisms in green areas of the city of Donostia-San Sebastián. Ecosistemas 29(1):1881. https://doi.org/10.7818/ECOS.1881 Urban green areas are suitable habitats for conserving soil biodiversity. The biota of urban soil performs a set of functions and associated ecosystem services of enormous importance. Unfortunately, the knowledge we currently have about soil organisms in urban environments is still very limited. The aim of this study was to identify those abiotic and biotic variables that have the greatest influence on the soil biodiversity of urban green areas. To this aim, thirty-eight urban green areas with different sizes, level of isolation (i.e., habitat fragmentation), soil physicochemical properties and type of vegetation were sampled in the city of Donostia-San Sebastián (Spain) to measure the diversity and composition of macrofauna, mesofauna and microorganisms (i.e., bacterial communities). Variables related to the soil carbon content and habitat fragmentation significantly explained the diversity and composition of soil organisms in the studied urban green areas. Even so, the percentage of the variance explained by these two variables was very low. Understanding the ecological processes in urban environments will be helpful for the design and management of urban green areas to promote conservation of the biodiversity of multiple taxonomic groups in urban soil.

PENGARUH BIOCHAR DAN PUPUK HIJAU Calopogonium mucunoides TERHADAP PERTUMBUHAN DAN HASIL KEDELAI (Glycine max L. Merril) SERTA MAKROFAUNA TANAH DI GAWANGAN TANAMAN KELAPA SAWIT

Oil palm plantations in Riau are very extensive and developed on marginal land. The utilization of oil palm plant for soybean cultivation is an alternative to increasing soybean production in Riau, because soybeans are classified as plants that tolerant to shade. The research aimed to study the interaction of biochar and Calopogonium mucunoides green fertilizer on growth and yield of soybeans and diversity of soil macrofauna in inter-rows of oil palm plant. The research was conducted in Pekanbaru, carried out in 7-year-old oil palm plant and soil science laboratory of the Faculty of Agriculture, University of Riau from April-August 2018. The research was done experimentally in a 3x3 factorial form using a completely randomized design (CRD). The first factor is biochar from coconut shell consists of 3 levels (0, 2,5 and 5 ton.ha-1). The second factor is Calopogonium mucunoides green fertilizer consists of 3 levels (0, 2,5 and 5 ton.ha-1). The parameters observed were plant height, pods per plant, percentage of pithy pods, seeds per plant, seed weight per plot, weight of 100 seeds, population density and relative density of soil macrofauna, and diversity index of soil macrofauna. The results showed 2,5 ton.ha-1 biochar followed by 2,5 ton.ha-1 Calopogonium mucunoides green fertilizer increased the number of pods per plant compared to controls. The total individuals and population of soil macrofauna increased at 5 ton.ha-1 biochar followed by 5 ton.ha-1 Calopogonium mucunoides green fertilizer with the family that was often found, namely Scarabaeidae. The diversity index of soil macrofauna is low.

KEANEKARAGAMAN MAKROFAUNA TANAH DI LAHAN BEKAS TERBAKAR DAN TIDAK TERBAKAR DI HUTAN LARANGAN ADAT RUMBIO

Soil macrofauna is a part of soil biodiversity that plays an important role in the improvement soil physical, chemical and biological properties. Fires that occur will affect the activity and presence of soil macrofauna which helps the decomposition process of organic materials such as providing better environmental facilities (Micro Habitat). This research aims to know species diversity and population density of soil macrofauna on burned and unburned land in The Rumbio Customary Forest. The research was carried out in The Rumbio Customary Forest and the Soil Laboratory Faculty of Agriculture University of Riau. The sampling of soil macrofauana was carried out on burned and unburned land in The Rumbio Customary Forest and also for measurement of soil physical-chemical factors. The research used the hand sorting method. This research showed that the population density of soil macrofauna on unburned land is higher if compared to burned land

English

Indonesia is a country with the third largest biodiversity after Brazil and Madagascar. Of the about 325.530 species of flora and fauna globally, an estimated 25% of the world's species are found in Indonesia. Macrofauna, a land animal that plays a role in influencing the soil ecosystem has specific environmental requirements that enables it to be used as biological indicators of ecosystem conditions, mainly rice paddy ecosystem. This research is necessary owing to the demand for an easy and accurate indicator in predicting soil fertility for farmers. In addition, this study conducted in July TO August 2018 can be used as an inventory of macrofauna indigenous species that may still remain in the paddy field, Dukuhseti district. The implementation of observations was done in paddy fields in the Dukuhseti district in Pati regency, Central Java. Macro fauna specimens and soil samples were taken at various points. 121 individual macro faunas were found and divided into three phyla and 10 Order. The results showed that macro fauna diversity was not always positively correlated with soil chemical properties. Total N, available P, organic C and pH is not directly proportional to the increasingly diverse types of macro fauna in a rice field. The soil’s chemical nature in the form of base saturation has a positive correlation with macro fauna diversity that makes it serve as an indicator of fertility. Base saturation in the fields can be associated with the presence of different kinds of macrofauna decomposers such as earthworms, millipedes and denitrivor. Indigenous macrofauna species was not found in the paddy fields in the Dukuhseti district due to intensive land management. Key words: Macrofauna, soil fertility, soil biology.

Submarine canyons influence macrofaunal diversity and density patterns in the deep-sea benthos

Submarine canyons are often morphologically complex features in the deep sea contributing to habitat heterogeneity. In addition, they act as major conduits of organic matter from the shallow productive shelf to the food deprived deep-sea, promoting gradients in food resources and areas of sediment resuspension and deposition. This study focuses on the Baltimore and Norfolk canyons, in the western North Atlantic Ocean, and investigates how different biogeochemical drivers influence canyon and slope macrofaunal communities. Replicated sediment cores were collected along the main axes (~180–1200 m) of Baltimore and Norfolk canyons and at comparable depths on the adjacent slopes. Cores were sorted, assessing whole community macrofaunal (>300 μm) abundance, diversity and standing stocks. Canyon communities were significantly different from slope communities in terms of diversity, abundance patterns and community assemblages, which were attributed to high levels of organic matter enrichment within canyons. There was a significant departure from the expected density-depth relationship in both canyons, driven by enhanced abundances between 800 and 900 m canyon depths, which was characterised as a deposition zone for organic matter. Bathymetric zonation, sediment dynamics, organic enrichment, and disturbance events were clear factors that structured the benthic communities in both Baltimore and Norfolk canyons. Coupling family-level community data, with sediment grain-size and biogeochemistry data explained community dynamics across depth and biogeochemical gradients, providing further evidence that canyons disrupt macrofaunal diversity and density patterns in the deep-sea benthos.

Functional and taxonomic (α and β) diversity patterns of macrobenthic communities along a depth gradient (19–2639 m): A case study from the southern Indian continental margin

Identifying the drivers that shape the biodiversity of a region is important to predict the response of ecosystems to environmental changes. Macrofaunal distribution pattern in the North Indian Ocean has so far been mainly studied considering small geographical areas, and using taxonomic diversity. The present study is a functional trait based approach aimed to identify the environmental drivers of macrofaunal distribution and diversity pattern from the relatively unexplored southern Indian continental margin. A total of 53 stations were sampled along six transects from a depth range of 19–2639 m. Along with taxonomic diversity (α and β), functional structure was assessed by using Biological Trait Analysis (BTA) and multivariate functional indices (richness, evenness, dispersal, divergence and Rao's Entropy). Principal Component Analysis identified a clear depth-related variability in the measured environmental parameters. Alpha diversity of the macrofaunal community decreased with increasing depth, a trend driven by depth related changes in the environmental factors (dissolved oxygen, sediment organic carbon and texture). However, functional diversity was only partially explained by the studied environmental variables which may be due to different factors governing the taxonomic and functional diversity pattern of macrofauna. Among the functional indices, only functional richness and evenness showed a clear trend of increase from shallow to deeper depths indicating that biodiversity-environment relations are complex. Therefore, investigating the response of macrofaunal community using multiple measure of diversity (α, β- and, functional diversity) was useful for providing an understanding of macrofaunal diversity pattern. The results of our study contribute to the growing knowledge on large-scale diversity gradients for marine macroinvertebrates, which may be critical for understanding ecological patterns and its response to both habitat and climatic change.

El Niño–Southern Oscillations and Pacific Decadal Oscillation as Drivers of the Decadal Dynamics of Benthic Macrofauna in Two Subtropical Estuaries (Southern Brazil)

The El Nino–Southern Oscillation (ENSO) and the Pacific Decadal Oscillation (PDO) are large-scale climatic phenomena affecting atmospheric and oceanic teleconnections, and thus triggering weather events at different temporal and spatial scales, both in tropical and extratropical areas. During 11 years (2007–2017), the influence of ENSO events (El Nino, La Nina and neutral), ENSO types (canonical and Modoki) and PDO phases (cold and warm) on meteorological conditions and macrobenthic invertebrates were analyzed in two distinct (tide-dominated and river-dominated) subtropical estuaries of Southern Brazil. The estuarine macrobenthic communities differed markedly, with higher species richness in the tide-dominated estuary (146 taxa) than river-dominated (44). We showed that long-term variability of benthic macrofauna in both estuaries was strongly influenced by the PDO and ENSO events. However, the signs of PDO and ENSO effects differed between the estuaries. While the main modulating force of the decadal variability of the macrofauna of the tide-dominated estuary was the PDO (19%), the river-dominated estuary was primarily influenced by the ENSO (9%). Besides, PDO and ENSO teleconnections have combined effects, with higher macrofauna dissimilarities during constructive periods (PDO Positive/EL Nino vs. PDO Negative/La Nina). Our findings indicate that: (1) The effects of the ENSO on coastal areas are dependent of the spatial scale and the intrinsic characteristics of each estuary; (2) Studies relating ENSO and biodiversity should consider the ENSO type (Modoki and canonical) and interdecadal modes, such as PDO, because the location of the warm pools and the intensity of induced heating affect the atmospheric teleconnections.

Soil macrofauna diversity and population dynamics in Indian Himalayan agroecosystems

Soil macrofauna diversity in Himalayan mountain agroecosystems has received negligible attention despite people’s dependence on soil fertility that determines crop yield for their sustenance. This study was carried out with the objective to determine differences in soil macrofauna taxonomic groups and abundance with soil depth (0–30 cm) in irrigated and non-irrigated wheat and rice crops of two dominant Himalayan mountain agroecosystems. At both the sites, a total of 11 macrofauna groups and 23 families were recorded. Macrofauna population across both crop seasons for non-irrigated fields was significantly greater (P < 0.05) than in irrigated fields. Macrofauna population significantly differed (P < 0.001) with soil depth and significantly declined with increasing soil depth (P < 0.001). The top soil (0–10 cm depth) contributed over 80% of the total macrofauna population. Macrofauna diversity in non-irrigated fields (H′ = 2.10) was greater than in irrigated fields (H′ = 1.86), but β diversity was greater in irrigated fields (1.67 vs 1.76). The two agroecosystem types significantly differed (P < 0.05) with soil depth and crop season. On the basis of presence or absence, the macrofauna groups were categorised as (i) present in soil year-round but exhibiting high density during warm and wet rainy season and (ii) present in soil only during the warm and wet rainy season. The non-irrigated fields had greater abundance of Coleoptera, Dermaptera, Hemiptera and Isoptera than the irrigated fields. This study highlights that the Himalayan mountain crop fields host a rather diverse and abundant macro-invertebrate community that should be efficiently used to promote soil fertility.

Communities of Soil Invertebrates in Protected Areas of the Southern Coast of Crimea

Soil and zoological studies of the arboretum of the Nikitsky Botanical Garden and Cape Martian Reserve (southern coast of Crimea) were carried out. Twenty two taxonomic groups of large invertebrate soil animals, whose number was about 1000 specimens/m2 and biomass about 25 g/m2, were found in the bulk stratozems of the garden and in natural red-colored soils of the reserve. The territory of botanical garden is characterized by a greater biomass and taxonomic diversity of the soil macrofauna than Cape Martian, but the community structure of both territories has similarities. Higher biodiversity and biomass in the garden are explained by increased soil moisture due to a sprinkling and high mosaicism of vegetation in the arboretum. Both territories have a high internal heterogeneity of the soil population, which is due to a variability of the soil properties, which is determined by differences in the bulk soils of the Nikitsky garden and the linear nature of erosion of the soils of Cape Martian. Along with a diversity of vegetation, these factors affect the heterogeneity of macrofauna distribution and provide a high biological β-diversity of the territory.

Assessment of Sediment and Benthic Macrofauna Distribution at Dar es Salaam Harbour Channel

Sediment and macrobenthic fauna distribution at Dar es Salaam harbour channel were investigated to attest the influence of sediment grain size distribution and total organic carbon contents on benthic macrofauna dominance and diversity. Sampling campaign was conducted from January to April, 2019 in 25 sampling stations along the channel. Sediment grain sizes ranged between 0.7405 and 0.00273 mm with an average of 0.0804 mm classified as medium silt. Sediment distribution showed an onshore-offshore pattern consisting of fine dark clay-silt sediments in the southern part of the harbour close to Mwalimu Nyerere Bridge, medium (sandy) at the harbour and coarse sandy offshore. Five classes of macrofauna were identified with sedentary Polychaetes (Diopatra cuprea) found in tubes and free forms being dominant in most of the sediment types, however more abundant in clay-silt. High species diversity index values were encountered in sediments with medium total organic carbon (TOC) and sediment grain sizes (sand-silt). Apparently, low species similarity indices were observed in all sediment type indicating significant dissimilarities in species composition among sediment grain sizes. Thus, the distribution of benthic macrofauna species along Dar es Salaam harbour channel is strongly influenced by the sediment grain sizes and organic carbon contents in sediments.

Influence of organic and mineral fertilizers on edafic fauna in Luvisol cultivated with sesame

The aim of this study was to evaluate the abundance and diversity of soil macrofauna under the influence of organic fertilization with goat manure compared to NPK fertilization in a Luvisol with two sesame cultivars. The experiment was conducted in Alagoinha - PB, under field conditions at the Experimental Station of the State Enterprise for Agricultural Research of Paraiba SA (Empresa Estadual de Pesquisa Agropecuária da Paraíba S.A. - EMEPA), approximately 1.24 miles away from the city. The design utilized was in random blocks with the treatment groups: T1: goat manure as organic source in BRS 196 cultivar (CNPA G4), T2: goat manure as organic source in BRS Seda cultivar, T3: mineral fertilizer with NPK in BRS 196 cultivar (CNPA G4), T4: mineral fertilizer with NPK in BRS Seda cultivar, T5: No fertilization in BRS 196 cultivar (CNPA G4) and T6: No fertilization in BRS Seda cultivar, with these fertilizers based on soil analysis, totaling 24 experimental units. In assessing the ecological behavior of soil macrofauna, it was measured the total number of individuals (abundance) and wealth of faunistic groups and communities comparisons were made using the Shannon biodiversity indices (H and equitability of Pielou (e). The treatment groups with organic fertilization were more abundant and rich as well as the faunistic group Hymenoptera had the highest abundance and lower diversity and uniformity, independently of the treatment groups studied and the samplings collected. The treatment groups studied did not influence the diversity and uniformity of edafic macrofauna.

Effects of clam hand dredging on macrofauna: A field experimental approach in a sandy tidal flat at a Marine Extractive Reserve

The clam Anomalocardia flexuosa (Linnaeus, 1767) is commonly fished in southern Brazil using highly efficient fishing gear—a hand dredge known as “hook”. We tested the immediate impact of this dredge on macrofauna in a sandy tidal flat in a Marine Extractive Reserve based on a BACI (Before After Control Impact) model. The sample design for the test was defined in five random areas located in a sand tidal flat. Each area was divided into three treatments, namely Control (undredged), Dredge 1 (D1) and Dredge 3 (D3), and the samples were collected before and after none, 1 and 3 dredge tows, respectively. Dredging had a quantitative impact mostly on the mollusk assemblage. The distribution and dominance patterns of the polychaete assemblage revealed the homogenizing effect of the hook. After dredging, macrofauna diversity was significantly lower. However, this effect was also observed in areas of greater initial abundance and diversity.

Increasing oxygen deficiency changes rare and moderately abundant bacterial communities in coastal soft sediments

Coastal hypoxia is a major environmental problem worldwide. Hypoxia-induced changes in sediment bacterial communities harm marine ecosystems and alter biogeochemical cycles. Nevertheless, the resistance of sediment bacterial communities to hypoxic stress is unknown. We investigated changes in bacterial communities during hypoxic-anoxic disturbance by artificially inducing oxygen deficiency to the seafloor for 0, 3, 7, and 48 days, with subsequent molecular biological analyses. We further investigated relationships between bacterial communities, benthic macrofauna and nutrient effluxes across the sediment-water-interface during hypoxic-anoxic stress, considering differentially abundant operational taxonomic units (OTUs). The composition of the moderately abundant OTUs changed significantly after seven days of oxygen deficiency, while the abundant and rare OTUs first changed after 48 days. High bacterial diversity maintained the resistance of the communities during oxygen deficiency until it dropped after 48 days, likely due to anoxia-induced loss of macrofaunal diversity and bioturbation. Nutrient fluxes, especially ammonium, correlated positively with the moderate and rare OTUs, including potential sulfate reducers. Correlations may reflect bacteria-mediated nutrient effluxes that accelerate eutrophication. The study suggests that even slightly higher bottom-water oxygen concentrations, which could sustain macrofaunal bioturbation, enable bacterial communities to resist large compositional changes and decrease the harmful consequences of hypoxia in marine ecosystems.

Benthic Fauna of Oga Bay (Novaya Zemlya, Kara Sea)

The benthic fauna of Oga Bay (Kara Sea, Novaya Zemlya archipelago) was studied in 2015–2016 during the R/V Akademik Mstislav Keldysh expeditions. Five grab stations at depths of 70–140 m were sampled (three grabs per station). Three macrobenthic communities consecutively replacing each other from the inner near-glacier part of the bay toward the outer slope were revealed. Concentration of suspended matter in the water column and in the near-bottom layer, caused by powerful sedimentation from the Goluboi (Oga) glacier was the main factor determining the macrobenthic communities distribution. An overall decrease in abundance, biomass and diversity of macrofauna was found in the area of glacier discharge. The community dominated by bivalve Portlandia arctica inhabits the main part of the bay. The peculiarities of the benthic communities of the Arctic glacial bays and fjords are discussed.

Soil Macrofauna Responses to Sugarcane Straw Removal for Bioenergy Production

Sugarcane (Saccharum officinarum) residue (straw) has been identified as a promising feedstock for bioenergy production, but excessive straw removal may impair soil macrofauna and related ecosystem services. To quantify straw removal effects on abundance, richness, and diversity of soil macrofauna, four experiments were conducted in Sao Paulo state, Brazil, under different edaphoclimatic conditions. A secondary goal was to evaluate seasonal changes on soil macrofauna and identify linkages between those changes and soil chemical and physical attributes. Four straw removal treatments (NR, no removal, LR, low removal, HR, high removal, and TR, total removal) were evaluated. Macrofauna and other soil attributes were sampled within the 0- to 0.30-m depth increment. Soil macrofauna were impaired by TR with the magnitude of response being related to both edaphoclimatic conditions and management practices. Numerous interactions among seasons, straw removal rates, and soil macrofauna were found, especially for total abundance and diversity of organisms. Partial straw removal (HR and LR) may be a strategy to protect soil health and increase bioenergy production with minimal effects on soil macrofauna, although long-term experiments are needed to confirm our hypothesis. The NR treatment generally had better soil quality as indicated by greater soil moisture, macropore number, soil organic carbon (SOC) content, and soil fertility, which led to a higher abundance of most macrofauna organisms. Total removal resulted in greater soil compaction and decreased macrofauna abundance, especially in clay soils. Our findings confirm that an integrated approach using soil indicators as guidelines should be adopted to better predict sustainable straw management practices for sugarcane in Brazil.

Efectos de la calidad del agua y del sustrato blando sobre la macrofauna bentónica de la zona intermareal en la Playa Pochomil, San Rafael del Sur

Se realizó un estudio espacial y temporal de la macrofauna bentónica en la zona intermareal de la Playa Pochomil, Nicaragua, en tres sitios denominados S.A (sitio arenoso), SRR (sitio rocoso con río) y S.R (sitio rocoso), respectivamente. Al final del estudio se contabilizaron un total de 596 individuos pertenecientes a cuatro Filos (Molusca, Anélida, Artrópoda y Equinodermata). La diversidad de macrofauna bentónica calculada mediante el índice de Shannon-Weaver, refleja valores de diversidad muy bajos durante todas las épocas de muestreo. Mediante el índice de Jaccard y Morisita-Horn, se evidenció que hubo baja similitud de especies. Además, se comprobó que la temporalidad no tuvo efecto directo significativo sobre la abundancia y distribución de la macrofauna bentónica, sino que ésta fue influenciada principalmente por las características físicas de los sitios de muestreo

Study of the benthic macrofauna and application of AMBI index in the coastal waters of Algeria

The aim of this of study was to examine the state of the benthic macrofauna community at six different sites in coastal waters of Algeria. The diversity of benthic macrofauna was studied and the AZTI marine biotic index (AMBI) was applied. Sampling was carried out during March and April 2018. Thus, 31 species were recorded. Higher species richness (13 species) was recorded in two sites. The highest density was estimated at 56.6 in / 0.1 m². Taxonomic analysis has shown the prevalence of Gastopoda, Bivalvia and Scaphopoda. Sediment analysis showed a low concentration of organic matter in the six sites. The AMBI index used in this study has been used extensively in Europe as indicador of marine pollution, but rarely used in Algeria. The AMBI values ​​were quite homogeneous over all the sites, and generally correspond to undisturbed states except for one site, which is slightly disturbed.

Macrofaunal Community Structure Following the Restocking of Northern Quahog (Mercenaria mercenaria) to Great South Bay, Long Island, NY

Overharvest of the once highly abundant northern quahog, or hard clam [Mercenaria mercenaria (Linnaeus, 1758)], has decimated local populations on Long Island, NY, and the ecosystem services they provide. Among the potential ecological consequences of the loss of hard clams, impacts on benthic community structure and function have not been well documented. This study took advantage of a large-scale hard clam restoration effort by The Nature Conservancy in Great South Bay, NY, to investigate these parameters. The benthic communities between areas planted with high densities of adult clams (i.e., spawner sanctuaries) and adjacent sites with no transplants were compared. In clam-stocked areas, there were greater trophic and taxonomic group densities, especially for some environmentally sensitive groups such as crustaceans, and increased species richness, which in turn altered community structure of the resident infauna. Differences between paired sites for macrofaunal diversity and community structure were also observed, likely reflecting larger scale differences in invertebrate communities. Minimal differences were observed in sediment porosity, carbon and nitrogen content, and total organic matter between adjacent areas with and without clams, although all of these parameters were significantly associated with community structure. Although shell density was significantly higher in clam-stocked plots, it explained little of the variation in macrofaunal composition on its own or in combination with other environmental parameters, but in combination with the living clams may have added enough environmental complexity to enhance densities of different trophic groups. Within the short period of 3 y, differences in the benthic community with the presence versus the absence of clams were already detectable. More long-term data incorporating the effect of processes at multiple scales are needed to gain insight into the complexity of rehabilitating coastal benthic environments following the removal of important species such as clams. The results of this work support the notion that M. mercenaria acts as an ecosystem engineer, modifying the environment by creating habitat and enhancing the abundance of other species.