不同空间配置的湿地植物群落对生活污水的净化作用研究

植物是湿地生态系统的重要组分,湿地湖滨植物群落物种组成和空间格局对湿地水体净化功能具有重要作用。选择茭草（Zizania caduciflora）、野菱（Trapa incisa）、金鱼藻（Ceratophyllum demersum）和蓖齿眼子菜（Potamogeton pectinatus）等4种云南高原湿地常见湖滨带植物物种,以不同配置方式分别构建4种不同植物群落：茭草-金鱼藻-金鱼藻（Z-C-C）、茭草-野菱-金鱼藻（Z-T-C）、茭草-蓖齿眼子菜-蓖齿眼子菜（Z-P-P）、和茭草-蓖齿眼子菜-金鱼藻（Z-P-C）,对不同植物群落净化污水的效果进行对比研究。结果表明：4种不同植物群落人工湿地对生活污水净化效果不同,经过Z-C-C群落处理后水体的COD降低率为（50.56±1.98）%,显著低于Z-T-C群落（69.66±4.15）%、Z-P-P群落（64.29±1.05）%,Z-P-C群落（66.67±1.13）%,（P〈0.05）;经过Z-T-C群落处理后水体TN降低率为（24.69±4.64）%,显著低于Z-C-C群落（53.29±0.71）%、Z-P-P群落（53.36±2.04）%、Z-P-C群落（54.44±0.29）%,（P〈0.05）;各群落对NH4＋-N去除率有显著差异（P〈0.05）,分别为（71.77±0.37）%,（67.22±0.53）%,（69.22±0.13）%,（80.85±0.31）%。研究表明：3种植物配置模式对生活污水的净化效果比2种植物配置模式的好;适当增加沉水植物的配置比例,可提高人工湿地对氮的去除效果;根系发达的植物具有更强的净化效果。     

Spatial patterns reveal negative density dependence and habitat associations in tropical trees

Understanding how plant species coexist in tropical rainforests is one of the biggest challenges in community ecology. One prominent hypothesis suggests that rare species are at an advantage because trees have lower survival in areas of high conspecific density due to increased attack by natural enemies, a process known as negative density dependence (NDD). A consensus is emerging that NDD is important for plant-species coexistence in tropical forests. Most evidence comes from short-term studies, but testing the prediction that NDD decreases the spatial aggregation of tree populations provides a long-term perspective. While spatial distributions have provided only weak evidence for NDD so far, the opposing effects of environmental heterogeneity might have confounded previous analyses. Here we use a novel statistical technique to control for environmental heterogeneity while testing whether spatial aggregation decreases with tree size in four tropical forests. We provide evidence for NDD in 22% of the 139 tree species analyzed and show that environmental heterogeneity can obscure the spatial signal of NDD. Environmental heterogeneity contributed to aggregation in 84% of species. We conclude that both biotic interactions and environmental heterogeneity play crucial roles in shaping tree dynamics in tropical forests.     

Spatial memory, habitat auto-facilitation and the emergence of fractal home range patterns

Animals interact with their habitat in a manner which involves both negative and positive feedback mechanisms. We apply a specific modeling approach, “multi-scaled random walk”, for the scenario where a spatially explicit positive feedback process emerges from a combination of a spatial memory-dependent tendency to return to familiar patches and a consequently objective or subjective improvement of the quality of these patches (habitat auto-facilitation). In addition to the potential for local resource improvement from physically altering a patch, primarily known from the ecology of grazing ungulates, auto-facilitation from site fidelity may also embed more subtle subjective, individual-specific advantages from patch familiarity. Under the condition of resource superabundance, fitness gain from intra-home range patch fidelity creates a self-reinforcing use of the preferred patches on expense of a broader foraging in a priori equally favorable patches. Through this process, our simulations show that a spatially fractal dispersion of accumulated locations of the individual will emerge under the given model assumptions. Based on a conjecture that intra-home range patch fidelity depends on spatial memory we apply the multi-scaled random walk model to construct a spatially explicit habitat suitability parameter H_ij, which quantifies the dispersion of the generally most constraining resource from the individual's perspective. An intra-home range set of observed H-scores, H_obs, can then be estimated from a simple 2-scale calculation that is derived from the local dispersion of fixes. We show how the spatially explicit habitat utilization index H_obs not necessarily correlates positively with the local density fluctuations of fixes. The H-index solves some well-known problems from using the pattern of local densities of telemetry fixes - the classic utilization distribution - as a proxy variable for relative intra-home range habitat quality and resource selection. A pilot study on a set of telemetry fixes collected from a herd of free-ranging domestic sheep with overlapping summer home ranges illustrates how the H-index may be estimated and interpreted as a first-level approach towards a more extensive analysis of intra-home range habitat resource availability and patch preferences. Spatial memory in combination with site fidelity requires a modeling framework that explicitly describes the property of positive feedback mechanism under auto-facilitation in a spatio-temporally explicit manner.     

Direct and indirect effects of climate and habitat factors on butterfly diversity

Many factors, including climate, resource availability, and habitat diversity, have been proposed as determinants of global diversity, but the links among them have rarely been studied. Using structural equation modeling (SEM), we investigated direct and indirect effects of climate variables, host-plant richness, and habitat diversity on butterfly species richness across Britain, at 20-km grid resolution. These factors were all important determinants of butterfly diversity, but their relative contributions differed between habitat generalists and specialists, and whether the effects were direct or indirect. Climate variables had strong effects on habitat generalists, whereas host-plant richness and habitat diversity contributed relatively more for habitat specialists. Considering total effects (direct and indirect together), climate variables had the strongest link to butterfly species richness for all groups of species. The results suggest that different mechanistic hypotheses to explain species richness may be more appropriate for habitat generalists and specialists, with generalists hypothesized to show direct physiological limitations and specialists additionally being constrained by trophic interactions (climate affecting host-plant richness).     

Influence of corallivory, competition, and habitat structure on coral community shifts

The species composition of coral communities has shifted in many areas worldwide through the relative loss of important ecosystem engineers such as highly branched corals, which are integral in maintaining reef biodiversity. We assessed the degree to which the performance of recently recruited branching corals was influenced by corallivory, competition, sedimentation, and the interactions between these factors. We also explored whether the species-specific influence of these biotic and abiotic constraints helps to explain recent shifts in the coral community in lagoons of Moorea, French Polynesia. Population surveys revealed evidence of a community shift away from a historically acroporid-dominated community to a pocilloporid- and poritid-dominated community, but also showed that the distribution and abundance of coral taxa varied predictably with location in the lagoon. At the microhabitat scale, branching corals grew mainly on dead or partially dead massive Porites ("bommies"), promontories with enhanced current velocities and reduced sedimentation. A demographic study revealed that growth and survival of juvenile Pocillopora verrucosa and Acropora retusa, the two most common branching species of each taxon, were affected by predation and competition with vermetid gastropods. By 24 months of age, 20-60% of juvenile corals suffered partial predation by corallivorous fishes, and injured corals experienced reduced growth and survival. A field experiment confirmed that partial predation by corallivorous fishes is an important, but habitat-modulated, constraint for branching corals. Competition with vermetid gastropods reduced growth of both branching species but unexpectedly also provided an associational defense against corallivory. Overall, the impact of abiotic constraints was habitat-specific and similar for Acropora and Pocillopora, but biotic interactions, especially corallivory, had a greater negative effect on Acropora than Pocillopora, which may explain the local shift in coral community composition.     

Biotic habitat complexity controls species diversity and nutrient effects on net biomass production

Canopy-forming plants and algae commonly contribute to spatial variation in habitat complexity for associated organisms and thereby create a biotic patchiness of communities. In this study, we tested for interaction effects between biotic habitat complexity and resource availability on net biomass production and species diversity of understory macroalgae by factorial field manipulations of light, nutrients, and algal canopy cover in a subtidal rocky-shore community. Presence of algal canopy cover and/or artificial shadings limited net biomass production and facilitated species diversity. Artificial shadings reduced light to levels similar to those under canopy cover, and net biomass production was significantly and positively correlated to light availability. Considering the comparable and dependent experimental effects from shadings and canopy cover, the results strongly suggest that canopy cover controlled net biomass production and species diversity by limiting light and thereby limiting resource availability for community production. Canopy cover also controlled experimental nutrient effects by preventing a significant increase in net biomass production from nutrient enrichment recorded in ambient light (no shading). Changes in species diversity were mediated by changes in species dominance patterns and species evenness, where canopy cover and shadings facilitated slow-growing crust-forming species and suppressed spatial dominance by Fucus vesiculosus, which was the main contributor to net production of algal biomass. The demonstrated impacts of biotic habitat complexity on biomass production and local diversity contribute significantly to understanding the importance of functionally important species and biodiversity for ecosystem processes. In particular, this study demonstrates how loss of a dominant species and decreased habitat complexity change the response of the remaining assembly to resource loading. This is of potential significance for marine conservation since resource loading often promotes low habitat complexity and canopy species are among the first groups lost in degraded aquatic systems.     

Spatial and temporal pattern in seagrass community composition and productivity in south Florida

We document the distribution and abundance of seagrasses, as well as the intra-annual temporal patterns in the abundance of seagrasses and the productivity of the nearshore dominant seagrass (Thalassia testudinum) in the south Florida region. At least one species of seagrass was present at 80.8% of 874 randomly chosen mapping sites, delimiting 12,800 km² of seagrass beds in the 17,000-km² survey area. Halophila decipiens had the greatest range in the study area; it was found to occur over 7,500 km². The range of T. testudinum was almost as extensive (6,400 km²), followed by Syringodium filiforme (4,400 km²), Halodule wrightii (3,000 km²) and Halophila engelmanni (50 km²). The seasonal maxima of standing crop was about 32% higher than the yearly mean. The productivity of T. testudinum was both temporally and spatially variable. Yearly mean areal productivity averaged 0.70 g m⁻²day⁻¹, with a range of 0.05–3.29 g m⁻² day⁻¹. Specific productivity ranged between 3.2 and 34.2 mg g⁻¹ day⁻¹, with a mean of 18.3 mg g⁻¹ day⁻¹. Annual peaks in specific productivity occurred in August, and minima in February. Integrating the standing crop for the study area gives an estimate of 1.4 × 1011 g T. testudinum and 3.6 × 10¹⁰ g S. filiforme, which translate to a yearly production of 9.4 × 10¹¹ g T. testudinum leaves and 2.4 × 10¹¹ g S. filiforme leaves. We assessed the efficacy of rapid visual surveys for estimating abundance of seagrasses in south Florida by comparing these results to measures of leaf biomass for T. testudinum and S. filiforme. Our rapid visual surveys proved useful for quantifying seagrass abundance, and the data presented in this paper serve as a benchmark against which future change in the system can be quantified. Received: 30 January 2000 / Accepted: 24 July 2000     

异质生境空心莲子草植物群落组成及物种多样性研究

研究草海湿地空心莲子草（Alternanthera philoxeroides）入侵对异质生境植物群落生活型、物种组成、重要值及物种多样性的影响,结果表明,①异质生境中群落生活型组成比例有差异,水生生境地面芽植物（H）∶隐芽植物（Cr）∶一年生植物（Th）为56∶38∶6;湿生生境为43∶36∶21。②异质生境中物种组成差异明显,水生生境试验样方包含9科13属16种,对照样方（无空心莲子草入侵）包含10科19属23种;湿生生境试验样方包含8科14属14种,对照样方有10科19属22种。空心莲子草入侵不同生境后群落内物种重要值变化及差异均较大,部分乡土物种在试验样方中减少甚至消失,水生生境和湿生生境群落中分别有30.44%、36.36%物种消失。③异质生境中空心莲子草重要值与物种多样性指数、生态优势度指数、均匀度指数均呈二项式函数关系;两种生境的多样性指数和均匀度指数均表现为随空心莲子草重要值先增加后减少,生态优势度指数均为先减少后增加,空心莲子草入侵对乡土植物群落物种多样性产生正向影响和负向影响,在群落中其重要值达25.8（水生生境）、18.9（湿生生境）时,是乡土植物多样性下降的临界点。     

Latitudinal variation in local interactions and regional enrichment shape patterns of marine community diversity

While communities are shaped by both local interactions and enrichment from the regional species pool, we propose a hypothesis that the balance of these forces shifts with latitude, with regional enrichment dominating at high latitudes and local interactions dominating at low latitudes. To test this hypothesis, we conducted a latitudinal-scale experiment with marine epifaunal communities. In four regions of the North Atlantic Ocean and Caribbean Sea, we used mimics of ecosystem engineers to manipulate biogenic structural complexity. We iteratively evaluated diversity patterns of experimental communities up to one year after deployment. Additional data were also collected from one of our tropical sites 2.5 years after initial deployment. As hypothesized, we found a reciprocal latitudinal gradient in the effects of the structurally complex mimics and regional enrichment. In the tropics, local diversity was always higher in association with the mimics than in exposed areas that were more open to predation. This effect was consistent across two spatial scales and beyond the one-year timescale of the experiment. In temperate communities, no consistent effects of the mimics on diversity were observed. However, the proportion of species from the regional species pool that were present at the local scale increased from the tropics to the temperate zone, consistent with the hypothesis that higher-latitude communities may experience greater influence from the regional species pool than communities at low latitudes. This study represents the first large-scale experimental demonstration that suggests that the relative impact of local interactions and regional enrichment on community diversity may depend on latitude.     

The influence of host diversity and composition on epidemiological patterns at multiple spatial scales

Spatial patterns of pathogen prevalence are determined by ecological processes acting across multiple spatial scales. Host-pathogen interactions are influenced by community composition, landscape structure, and environmental factors. Explaining prevalence patterns requires an understanding of how local determinants of infection, such as community composition, are mediated by landscape characteristics and regional-scale environmental drivers. Here we investigate the role of local community interactions and the effects of landscape structure on the dynamics of barley and cereal yellow dwarf viruses (B/CYDV) in the open meadows of the Cascade Mountains of Oregon. B/CYDV is an aphid-transmitted, generalist pathogen of over 100 wild and cultivated grass species. We used variance components analysis and model selection techniques to partition the sources of variation in B/CYDV prevalence and to determine which abiotic and biotic factors influence host-pathogen interactions in a Cascades meadowsystem. B/CYDV prevalence in Cascades meadows varied by host species identity, with a significantly higher proportion of infected Festuca idahoensis individuals than Elymus glaucus or Bromus carinatus. Although there was significant variation in prevalence among host species and among meadows in the same meadow complex, there was no evidence of any significant variation in prevalence among different meadow complexes at a larger spatial scale. Variation in prevalence among meadows was primarily associated with the local community context (host identity, the relative abundance of different host species, and host species richness) and the physical landscape attributes of the meadow. These results highlight the importance of local host community composition, mediated by landscape characteristics such as meadow aspect, as a determinant of the spatial pattern of infection of a multi-host pathogen.     

Modelling the effects of litter decomposition on tree diversity patterns

Current theories may not fully explain why latitudinal patterns of plant diversity differ between terrestrial and flooded ecosystems. Moreover, the co-occurrence of hyper diverse stands in lowland tierra firma (not inundated) forests and almost monospecific stands in mangroves and gallery riparian vegetation within the tropics remains enigmatic. Building on evidence from ecology and agriculture, we present a new model investigating the hypothesis that, besides the general positive feedback of plant growth by nutrients release, litter decomposition builds up an intra-specific negative feedback functionally linked with tree diversity. The model results were compared with extensive published data sets both across and within latitudinal zones. The model predicts correctly the biomass production and decomposition process, as well as the number of tree species, their relative abundance in all environmental conditions providing a novel, putative explanation also for the diversity variations observed within the tropics. The model demonstrates a possible mechanistic link between the carbon cycle and biodiversity patterns, which is interesting in the debate about advancing in the direction of a unifying ecosystem theory.     

微生物群落结构和多样性解析技术研究进展

微生物群落结构和多样性是微生物生态学和环境科学研究的热点内容，对于开发微生物资源，阐明微生物群落与其生境的关系，揭示群落结构与功能的联系，从而指导微生物群落功能的定向调控具有重要意义。基本按照年代顺序概述了常用的微生物群落结构及多样性解析技术，同时也体现了解析技术由片面向全面、由低分辨水平向高分辨水平的发展过程。20世纪70年代以前，对环境微生物群落结构及多样性的认识依赖传统的培养分离方法，方法的分辨水平低，认识是不全面的和有选择性的；20世纪70年代和80年代，在微生物化学成分分析的基础上建立了生物标记物方法(醌指纹法、磷脂脂肪酸法等)，对微生物群落结构和多样性的认识进入到较客观的层次上；在80和90年代，以DNA为目标物的现代分子生物学技术(rRNA基因测序技术、基因指纹图谱等)比较精确地揭示了微生物种类和遗传的多样性，并给出了关于群落结构的直观信息。指出了每种解析技术的功能特点和局限性，并展望了解析技术的发展趋势是原位、快速、灵敏、高通量和准确定量。     

长白山春季不同植被类型中土壤线虫的群落结构

2001年和2002年春季,对长白山白北坡不同海拔的阔叶红松林、红松云冷杉混交林、暗针叶林、岳桦林和高山苔原中土壤线虫进行了研究.结果表明,5个样地中共鉴定到线虫7684条,分别隶属于2纲8目27科60属.其中绕线属Plectus,滑刃属Aphelenchoides,垫刃属Tylenchus,小杆属Rhabditis,盘旋属Rotylenchus和鹿角唇属Cervidellus为优势属,优势属线虫主要分布在枯枝落叶层中.土壤线虫数量与土壤含水量显著相关(r=0.357;P<0.01),在不同深度和植被群落中丰富度最大的是食细菌类群线虫.土壤线虫总数和营养类群在不同土壤深度中差异显著(P<0.05);食真菌类群数量与食细菌类群数量之和与植食类群数量之比(WI)和线虫成熟指数(MI)在不同深度也存在明显差异(P<0.01).     

增温对荒漠草原植物群落组成及物种多样性的影响

以短花针茅荒漠草原为研究对象,通过采用远红外线辐射器模拟增温的方法,探讨了增温对荒漠草原植物群落结构及生物量和物种多样性的影响。结果表明：由于远红外线辐射器的增温作用,在2012年整个生长季内,增温样地10、20、30 cm土壤平均温度与对照样地相比,平均增加了0.39、0.38、0.31℃;各土层土壤含水量较对照平均减少0.76%、0.73%、0.60%。受温度升高及土壤含水量减少的影响,模拟增温6个生长季后,与对照样地相比,群落的高度整体增加,密度、盖度、频度表现为部分物种增加和部分物种减少的趋势,冷蒿（Artemisia frigida）等物种的重要值下降,阿氏旋花（Convolvulus ammanii）等物种的重要值上升,但是增温没有明显改变植物群落的组成。同时,增温处理使荒漠草原禾草的盖度减少,杂类草的盖度增加,半灌木和一两年生植物分盖度未发生明显变化;增温使地上地下生物量出现了不同程度的减少,在0~30 cm土壤深度地下生物量分配中,增温样地0~10 cm分配比例（81.23%）小于对照（86.07%）,10~20 cm分配比例（11.55%）大于对照（9.16%）;20~30 cm 分配比例（7.22%）大于对照（4.77%）,增温使得地下生物量分配格局向深层转移。增温后,增温样地植物Shnnon-Winener指数降低,Pielou均匀度指数升高,温度升高使荒漠草原植物群落的均匀度增加,但并没有提高草地植物的物种多样性。     

Incubation time, functional litter diversity, and habitat characteristics predict litter-mixing effects on decomposition

Plant diversity influences many fundamental ecosystem functions, including carbon and nutrient dynamics, during litter breakdown. Mixing different litter species causes litter mixtures to lose mass at different rates than expected from component species incubated in isolation. Such nonadditive litter-mixing effects on breakdown processes often occur idiosyncratically because their direction and magnitude change with incubation time, litter species composition, and ecosystem characteristics. Taking advantage of results from 18 litter mixture experiments in streams, we examined whether the direction and magnitude of nonadditive mixing effects are randomly determined. Across 171 tested litter mixtures and 510 incubation time-by-mixture combinations, nonadditive effects on breakdown were common and on average resulted in slightly faster decomposition than expected. In addition, we found that the magnitude of nonadditive effects and the relative balance of positive and negative responses in mixtures change predictably over time, and both were related to an index of functional litter diversity and selected environmental characteristics. Based on these, it should be expected that nonadditive effects are stronger for litter mixtures made of functionally dissimilar species especially in smaller streams. Our findings demonstrate that effects of litter diversity on plant mixture breakdown are more predictable than generally thought. We further argue that the consequences of current worldwide homogenization in the composition of plant traits on carbon and nutrient dynamics could be better inferred from long-duration experiments that manipulate both functional litter diversity and ecosystem characteristics in "hotspots of biodiversity effects," such as small streams.     

Spatial characteristics of habitat patches and population survival

The effect of the spatial arrangement of habitat patches on the survival of resident populations were considered in a stochastic model using population parameters appropriate to Peromyscus leucopus. The 34 possible arrangements of connections among five otherwise identical patches were simulated in order to determine the survival probabilities and population sizes.The main findings are that populations in completely isolated patches have lower survival probabilities than those in patches that are connected to other patches, are connected to the survival probabilities of populations in connected patches increases with the size of the largest geometric figure of which the patch is a part. The results are discussed in the context of resource management.     

Long-term patterns in tropical reforestation: plant community composition and aboveground biomass accumulation.

Primary tropical forests are renowned for their high biodiversity and carbon storage, and considerable research has documented both species and carbon losses with deforestation and agricultural land uses. Economic drivers are now leading to the abandonment of agricultural lands, and the area in secondary forests is increasing. We know little about how long it takes for these ecosystems to achieve the structural and compositional characteristics of primary forests. In this study, we examine changes in plant species composition and aboveground biomass during eight decades of tropical secondary succession in Puerto Rico, and compare these patterns with primary forests. Using a well-replicated chronosequence approach, we sampled primary forests and secondary forests established 10, 20, 30, 60, and 80 years ago on abandoned pastures. Tree species composition in all secondary forests was different from that of primary forests and could be divided into early (10-, 20-, and 30-year) vs. late (60- and 80-year) successional phases. The highest rates of aboveground biomass accumulation occurred in the first 20 years, with rates of C sequestration peaking at 6.7 +/- 0.5 Mg C x ha(-1) x yr(-1). Reforestation of pastures resulted in an accumulation of 125 Mg C/ha in aboveground standing live biomass over 80 years. The 80 year-old secondary forests had greater biomass than the primary forests, due to the replacement of woody species by palms in the primary forests. Our results show that these new ecosystems have different species composition, but similar species richness, and significant potential for carbon sequestration, compared to remnant primary forests.     

Increased primary production shifts the structure and composition of a terrestrial arthropod community

Numerous studies have examined relationships between primary production and biodiversity at higher trophic levels. However, altered production in plant communities is often tightly linked with concomitant shifts in diversity and composition, and most studies have not disentangled the direct effects of production on consumers. Furthermore, when studies do examine the effects of plant production on animals in terrestrial systems, they are primarily confined to a subset of taxonomic or functional groups instead of investigating the responses of the entire community. Using natural monocultures of the salt marsh cordgrass Spartina alterniflora, we were able to examine the impacts of increased plant production, independent of changes in plant composition and/or diversity, on the trophic structure, composition, and diversity of the entire arthropod community. If arthropod species richness increased with greater plant production, we predicted that it would be driven by: (1) an increase in the number of rare species, and/or (2) an increase in arthropod abundance. Our results largely supported our predictions: species richness of herbivores, detritivores, predators, and parasitoids increased monotonically with increasing levels of plant production, and the diversity of rare species also increased with plant production. However, rare species that accounted for this difference were predators, parasitoids, and detritivores, not herbivores. Herbivore species richness could be simply explained by the relationship between abundance and diversity. Using nonmetric multidimensional scaling (NMDS) and analysis of similarity (ANOSIM), we also found significant changes in arthropod species composition with increasing levels of production. Our findings have important implications in the intertidal salt marsh, where human activities have increased nitrogen runoff into the marsh, and demonstrate that such nitrogen inputs cascade to affect community structure, diversity, and abundance in higher trophic levels.     

Spatial structure and habitat associations of demersal assemblages in the Gulf of Lions: a multicompartmental approach

Experimental trawl surveys were performed in the Gulf of Lions. A multicompartmental approach was used to study the spatial distribution of demersal assemblages and to estimate their associations with two other components of the ecosystem: the benthic macrofauna and substratum type. At the Gulf scale, we found that these components explained 38 and 19% of the total variability of the spatial organization of groundfishes, respectively. Our results showed that groundfish and benthic macrofauna species were primarily distributed along a coast–open sea gradient and secondarily along a longitudinal axis. The longitudinal variability of the spatial organisation of species was maximal in the shelf area, whereas the upper-slope and coastal areas were characterized by strong homogeneity. Although no partitioning could be made based on their spatial distribution, the coastal groundfish assemblages were split into two groups. In the first group, groundfishes were strongly associated with both benthic macrofauna and type of substratum; in the second group, they were strongly independent of these two components. Furthermore, in the Gulf of Lions, the presence of productive zones associated with the Rhône river plume or with shelf-break upwelling seemed to attract some groundfishes. This study illustrates how useful such a multicompartmental approach can be for both fisheries management and community ecology.