Mayfly production in a New Zealand glacial stream and the potential effect of climate change

In contrast to the northern hemisphere where species of Chironomidae are usually the dominant benthic invertebrates in the coldest upper reaches of glacial streams, mayflies (Deleatidium spp.: Leptophlebiidae) predominate in equivalent conditions in New Zealand. We examined the life histories and annual production of Deleatidium spp. at two sites on the Matukituki River (South Island, New Zealand) and at three sites in its glacier-fed tributary, Rob Roy Stream. Mean annual water temperature at the five sites ranged from 2.1 to 7.0°C. Monthly sampling showed that mayfly populations were poorly synchronised at all sites but were probably univoltine. The large Deleatidium cornutum was the dominant mayfly species found at the upper sites (Sites 1 and 2) on Rob Roy Stream, whereas above the confluence with Matukituki River (Site 3) it co-existed with a complex of smaller species we refer to as D. “angustum”. Deleatidium “angustum” also dominated at the Matukituki sites. Deleatidium production calculated for the five sites, assuming an 11-month nymphal life, ranged from 0.48 g dry weight/m²/year (Site 1) to 3.07 g dry weight/m²/year (Site 3). The values for D. cornutum at Sites 2 and 3 are high for a species of Deleatidium and reflect its large size. This species appears to be strongly adapted for growth at low temperatures. Climate change scenarios for New Zealand predict the gradual and ultimate loss of small South Island glaciers and a consequent warming of streams as runoff from rainfall and snow melt becomes more dominant in spring. As a result, suitable habitats will be lost for cold-water specialists such as D. cornutum, and they are likely to suffer reductions in their distributional range and local extinction. In contrast, species such as those in the D. “angustum” complex may extend their ranges into streams formerly dominated by glacial meltwater. Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users. Handling editor: S. Stendera     

Resource dynamics and detritivore production in an acid stream

1. Life history patterns and production of eight shredder‐detritivore species were studied in relation to the detritus dynamics of a small acidic stream in England. Mean annual detritus inputs (direct and lateral sources combined) were approximately 400 g m^?2 year^?1 and showed significant seasonal and annual variation. 2. Detritus standing stock did not increase significantly during times of high input, reflecting low retention efficiency. However, the mean detritus standing stock was relatively large (108 g m^?2) reflecting a slow decomposition rate typical of acid streams. 3. Four species were univoltine with highly synchronous patterns of emergence and recruitment (Leuctra inermis, Leuctra hippopus, Capnia vidua and Amphinemura sulcicollis). Two species were univoltine with extended patterns of emergence and recruitment (Nemoura cinerea, Potamophylax cingulatus). Leuctra nigra was apparently semivoltine, while Protonemura meyeri showed two successive cohorts in the second year of the study, suggesting either bivoltinism or cohort splitting. 3. Secondary production of the dominant shredders was 1.67 g m^?2 year^?1 in 1997 and 1.99 g m^?2 year^?1 in 1998, which is low compared with other small European streams. This was probably because of an impoverished invertebrate community and poor food quality associated with acid conditions. Food availability probably did not account for the low production as the detritus standing stock far exceeded the estimated shredder ingestion of 42–50 g m^?2 year^?1. 4. Despite low overall shredder production, species‐specific production was high, possibly because of competitive release in this species‐poor acid stream. Periods of high production and growth showed no relationship with detritus availability but were closely related to life history.     

Comprehensive DNA barcodes for species identification and discovery of cryptic diversity in mayfly larvae from South Korea: Implications for freshwater ecosystem biomonitoring

DNA barcoding of aquatic macroinvertebrates holds much promise as a tool for taxonomic research and for providing baseline reference for phylogenetic analysis and aquatic ecosystem biomonitoring. We obtained 112 novel sequences of the barcode region of the mitochondrial DNA cytochrome c oxidase subunit I gene representing 11 families, 25 genera, and 43 species of mayfly (Insecta: Ephemeroptera) from South Korea. No species shared barcode sequences and all can be identified with barcodes with a possible exception of some species. Minimum levels of interspecific genetic distances ranged from 6.7 to 32.9% (mean: 23.7%), whereas average levels of intraspecific divergence was 3.7%. The latter value was inflated by the presence of very high divergences within some taxa. In fact, approximately 33.3% (15/45) of the species included two or more haplotype clusters showing greater than 5.0% sequence divergence and some values were as high as 32.9%. Many of the species with high intraspecific divergences are para‐ or polyphyletic and represent the possibility of species complexes. Our study suggests that type or topotype specimens should be sequenced to identify accurate barcoding clusters with morphological species concepts and also to determine the status of currently synonymized species.     

In situ measurements of net primary production in a Colorado mountain stream

Six stations were established on a Colorado mountain stream, and net primary productivity was measured in situ during all seasons. For 24-hour periods the dissolved oxygen and temperature of the water were electronically monitored over an undisturbed 1 x 1 m section of rubble bottom enclosed by a large plastic dome tightly fitted to the substrate. A submerged pump maintained a current within the dome, and the whole apparatus was submerged below the stream level. The bottom community net metabolism varied between heterotrophy and autotrophy with no correlations with altitude, season, light, water chemistry, and temperature. Readings were all very low and ranged from -27.38 to 35.59 grams of carbon fixed per square meter per year. There were no correlations between biomass of the bottom fauna and net community productivity.Contribution No. 71, University of Colorado Limnology Laboratory     

Life cycle and production of Skwala parallela (Frison) (Plecoptera: Perlodidae) in a Colorado montane stream

The life cycle and production of Skwala parallela, a perlodid stonefly, was investigated in a third-order Colorado montane stream. The species exhibited a univoltine life cycle with a distinct cohort. Small nymphs appeared in May. Rapid growth was exhibited throughout summer and autumn. During winter, growth slowed somewhat but was continuous until April. Maximum density of 34 nymphs/m² occurred in July. Based upon the instantaneous growth method, annual production was 395.3 mg/m² or 3.95 kg/ha dry weight with a P/B ratio of 4.4     

Production by Hexagenia limbata in a warm-water reservoir and its association with chlorophyll content of the water column

We investigated the productivity of nymphs of the mayfly Hexagenia limbata in Lake Waco, a central Texas reservoir, and assessed its association with chlorophyll content of the water. We hypothesized that food availability measured as chlorophyll content of the water may directly associate with growth of Hexagenia and predict population productivity. To test this, we compared production by mayfly populations at two stations in the same reservoir; a northern station receiving water input with high chlorophyll content, and a southern station receiving water with low chlorophyll content. Both stations had similar substrate type and abundant mayflies. Benthic samples were collected from October 1984 through September 1985, and dissolved oxygen and temperature of the water were monitored.Annual production (size-frequency method) was 1270 mg m^–2 (P/B = 7.5) at the northern station and 1990 mg m^–2 (P/B = 6.1) at the southern station. The mean standing crop was 323 mg m ^{– 2} at the southern station and 169mg m^–2 at the southern station. Densities of mayflies at the two stations were not significantly different.Mean chlorophyll concentration (total mg pigment) during the sampling period was 23.5 mg m^–3 at the northern station and 16.7 mg m ^{– 3} at the southern station. Therefore, the station with lower mean chlorophyll content had higher secondary productivity by Hexagenia. Conversely, the station with higher mean chlorophyll content had lower mayfly productivity. The productivity of the mayfly populations did not positively associate with the chlorophyll content of the water, and chlorophyll content did not predict the success of the population of Hexagenia. Variation in mayfly growth success was associated with differences in temperature and dissolved oxygen. The northern station with higher chlorophyll content and lower productivity had low dissolved oxygen and temperatures higher than optimum for growth.     

Impact of simulated drought on ecosystem biomass production: an experimental test in stream mesocosms

Climate models predict widespread shifts in precipitation patterns and increases in the frequency of extreme events such as droughts, but consequences for key processes in affected ecosystems remains poorly understood. A 2‐year manipulative experiment used a series of stream mesocosms to test the effect of recurrent drought disturbance on the composition and secondary production of macroinvertebrate consumer assemblages and functional groups. On average, secondary production in drought‐disturbed communities (mean 4.5 g m^?2 yr^?1) was less than half of that that in controls (mean 10.4 g m^?2 yr^?1). The effects of the drought differed among functional feeding groups, with substantial declines for detritivore shredders (by 69%) and engulfing predators (by 94%). Contrasting responses were evident among taxa within most functional feeding groups, ranging from extirpation to irruptions in the case of several small midge larvae, but production of most species was suppressed. Taxon‐specific responses were related to body mass and voltinism. The ratio of production to biomass (community P/B) increased under drought, reflecting a shift in production from large long‐lived taxa to smaller taxa with faster life cycles. This research provides some of the first experimental evidence of the profound effects that droughts can have on both the structure and functioning of aquatic ecosystems.     

Life history differences of Psilotreta locumtenens (Trichoptera: Odontoceridae) in two reaches of a mountain stream in Korea

The life history traits of the caddisfly, Psilotreta locumtenens Botosaneanu (Odontoceridae), were studied in two stream reaches with different thermal ranges (main and branch streams) of the Gapyeong Stream, a typical mountain stream located in the central Korean Peninsula. Psilotreta locumtenens larvae were quantitatively sampled monthly from November 2008 to July 2010, and biweekly during the emergence period (late April to early July), using a Surber sampler (30 × 30 cm). Adults were quantitatively sampled with a sweep net. Larval density in the main stream (324.21 ± 38.59 m^?2) was higher than that in the branch stream (60.48 ± 10.86 m^?2). The larvae hatched in the early summer and overwintered as 5th and 3rd instars in the main and branch streams, respectively. The emergence peak at the main stream was approximately 2 weeks earlier. The sex ratio at both sites was approximately 0.3. The life history in both streams was univoltine. Secondary production in the main stream was much higher than in the branch stream, owing to high larval densities, and the P/B ratios at the two sites were similar. This study demonstrated remarkable differences in larval growth patterns and emergence peaks in P. locumtenens between the two stream reaches due to differences in accumulated degree days (230.30 DD) and other phenological cues such as daily mean threshold water temperature (9°C) during the ascending phase, despite their relatively small mean annual water temperature difference of 0.58°C.     

Effects of logging on macroinvertebrate production in a sand-bottomed, low-gradient stream

1. Macroinvertebrate production and macrophyte growth were studied in logged and unlogged sections of a sand‐bottomed, low‐gradient, blackwater stream on the Coastal Plain of Virginia, U.S.A. A section of the catchment had been clear‐cut 3 years prior to sampling. No logging occurred in the upstream area of the catchment, which had experienced almost no land disturbance by humans for over 100 years. 2. A primary difference among the logged and unlogged sections of the stream was in the abundance of macrophytes. The combined biomass of Sparganium americanum and of Chara sp. was over 300‐times greater in the logged than the unlogged section. 3. Annual macroinvertebrate production in the sediment was higher in the unlogged section (41 g dry mass m^–2) than in the logged section (25 g m^–2). 4. Annual macroinvertebrate production on Sparganium was higher in the logged section (10 g m^–2 of plant surface area) than in the unlogged section (6 g m^–2). Annual production associated with Chara, which occurred only in the logged section, was 196 g m^–2 of stream bottom covered by this plant. 5. Whole‐stream annual macroinvertebrate production, calculated by summing habitat‐specific production that was weighted by habitat availability, was greater in the logged section (103 g m^–2) than in the unlogged section (41 g m^–2). Sediments supported 99% of the annual production in the unlogged section, whereas macrophytes supported 76% in the logged section. 6. Much of the additional macroinvertebrate production in the logged section was by collector‐filterers living on macrophytes. Production by collector‐gatherers was also greater in the logged section, whereas production by other functional feeding groups changed little with logging. 7. Although logging along high‐gradient, rocky streams also results in increased macroinvertebrate production, that increase often is stimulated by greater periphyton growth rather than the macrophyte growth observed in this low‐gradient stream.     

The response of macroinvertebrate production to a pollution gradient in a headwater stream

1. This study quantified patterns of macroinvertebrate secondary production and stored benthic organic matter along a gradient of pollution and habitat channelisation over a 3‐km reach of Goosefare Brook, a first‐order stream in southern Maine (U.S.A.). 2. Whole‐community invertebrate production decreased from 26.4 g ash‐free dry mass (AFDM) m⁻² year⁻¹ at the reference station to 1.1 g AFDM m⁻² year⁻¹ at stations with the greatest levels of pollution. Production decreased along the pollution gradient for most taxa, although decreases were partly offset by production increases in tolerant taxa. Biomass turnover rates (P/B) were less affected by the stresses than was production. 3. Differences in functional characteristics of the community were evident at stations with channelised habitat, but overall production declined in a linear pattern that mirrored the pollution gradient. Stored organic matter showed a decline along the gradient, but was also lower at channelised stations. Populations of taxa with documented pollution tolerance were more likely to maintain or increase production and P/B. 4. Decreasing biomass because of decreasing stored organic matter and lethal effects of pollutants resulted in shifts in the pathways of energy flow observed at stations exposed to moderate physical or chemical stress, to the loss of most taxa and an extreme (96%) decrease in production at the stations receiving the highest levels of metal pollution. 5. The shifting prominence of different taxa along a continuum of stress in Goosefare Brook shows that describing the nature of an impairment in a functional context requires consideration of chemical stressors, habitat alterations and food resources.     

Life-history strategies and production of Tinodes waeneri (L.) (Trichoptera) in Lake Esrom,Denmark

The life cycle and production of Tinodes waeneri (L.) was examined at five shallow littoral localities in Lake Esrom, Denmark, during 1979/80. Five larval instars were demonstrated. The differences in temporal composition of instars indicated three different life cycles. A bivoltine strategy was shown for the most exposed locality which also had the highest average abundance equal to 11 500 ind. m^–2. A univoltine population was found in the more sheltered NW part of the lake with an average density of 1 500 ind. m^–2. At the three remaining stations the life cycles were partly bivoltine with wintering populations of mixed cohorts and densities between 10 500 and 3 000 ind. m^–3. Two distinct flight periods with maxima in June and August were demonstrated for bi- and partly bivoltine populations. Differences in rates of growth and elimination added to the variability in life cycle. Growth rates peaked in August (5.0–7.4% d^–1) at an average temperature of 20°C. Estimates of production ranged from 1.9 to 17.5 g AFDW m^–2 a^–1 with an average of 8.0 g AFDW m^–2. The P/B ratios, which were within the expected range for uni- and bivoltine populations of trichopterans, were 5.73 for the bivoltine population and 3.31 for the univoltine population.Estimates of consumption revealed that the populations could be sustained by autochthonous epilithic production in the habitats. Variability in the quality and seasonal availability of food were judged to influence the type of life cycle.Lake Esrom Littoral Research Publ. No. 8. Publication No. 385 from the Freshwater Biological Laboratory, University of Copenhagen, 51, Helsingørsgade, DK-3400 Hillerød, Denmark.Lake Esrom Littoral Research Publ. No. 8. Publication No. 385 from the Freshwater Biological Laboratory, University of Copenhagen, 51, Helsingørsgade, DK-3400 Hillerød, Denmark.     

Life history and production of Agapetus quadratus (Trichoptera: Glossosomatidae) in a temporary, spring-fed stream

1. The life history and trophic basis of production of the caddisfly grazer Agapetus quadratus were studied in the torrent Gorg Blau, a spring‐fed stream on the island of Majorca that dries annually during summer. 2. Quantitative random samples were taken every 2–3 weeks during an annual surficial flow period, from November 2000 to mid‐July 2001. Instars of field‐collected larvae were determined by measurements of head width and pronotum length, and the sex of all pupae was determined to study sexual dimorphism and sex ratio. 3. Stage‐frequency histograms suggested a trivoltine population, with an average cohort time of 4 months. Larval development was asynchronous, with continuous growth and overlapping generations. Recruitment peaks were identified in mid‐November, early March and late June, indicative of winter, spring and summer generations. On average, females were larger than males and the mean sex ratio was 2 : 3 (females : males). Population densities and biomasses derived from the field data were used to calculate production and turnover rate. 4. Annual production of A. quadratus in the torrent Gorg Blau (4.80 g dry mass m^?2 year^?1) was the highest ever reported for the genus, being comparable with that estimated for some insects with rapid development and multiple cohorts. 5. Estimates of production of A. quadratus were combined with foregut content analysis to estimate the fraction of total production derived from the principal food sources: algae and organic detritus. Algae supported a major proportion of the production of this grazer. 6. The low density of predators characteristic of many temporary streams, and the small amplitudes in discharge and temperature during most of the wet period that characterise the spring habitats might allow high levels of grazer production in this particular Mediterranean stream.     

The effect of continuous physical disturbance on mayflies of a tropical stream: an experimental approach

Field experiments to examine the effect of continuous physical disturbance on the Ephemeroptera of the Naro Moru River, Kenya, wereundertaken from June 1993 to January 1994. Continuous disturbance wasadministered on a randomly selected subsite of the sediment surface.Artificial physical disturbance within the experimental subsite involvedcontinuous local displacement, shifting and stirring of the streambedsurface substrates (about 10 cm depth) by hand every one minute for 10 or 14min. Three control samples were also taken randomly from the sedimentsurface of an undisturbed stratified area of the study riffle at the startof each disturbance occasion. All samples were collected using a Hesssampler (surface sampling area of 3.142 dm²; meshsize 80μm). Seven mayfly species were particularly abundant and these included Afronurus sp., Afroptilum sudafricanum LESTAGE, Baetis s.l., Baetis(Nigrobaetis) sp. 1, Baetis (Nigrobaetis) sp. 2, Caenis sp. and Choroterpes(Euthraulus) sp. About 83,8% of the total mayfly density and88.1% of the biomass were removed from the streambed surface withinthe first three minutes of continuous physical disturbance. A mayfly biomassof 33.7391 mg dm² and total density of 1357.6 inddm² were collected from the disturbed subsite during the studyduration. Further, a biomass of about 42.8335 mg dm⁻²and total density of 2366 ind dm⁻² were collected fromthe control sites. There was a near-complete depletion of mayflyindividuals from the topmost sediment layer within 14 min of continuousdisturbance. This revised version was published online in July 2006 with corrections to the Cover Date.     

Life histories, production dynamics and resource utilisation of mayflies (Ephemeroptera) in two tropical Asian forest streams

SUMMARY 1. A 2‐year study of the life histories, production dynamics and resource utilisation of five mayfly species was undertaken in two forest streams in Hong Kong [Tai Po Kau Forest Stream (TPKFS) and Shing Mun River (SMR)]. Afronurus sp. and Cinygmina sp. (Heptageniidae), Procloeon sp. and Baetiella pseudofrequenta (Baetidae), and Choroterpes sp. (Leptophlebiidae) were abundant in both streams and contributed more than 50% of the total mayfly populations. 2. All species had asynchronous larval development with recruitment occurring throughout the year. Mean annual production (all mayflies combined) was 3.1 and 2.0 g dry weight m^?2 year^?1 in SMR and TPKFS, respectively – the higher value at SMR reflecting greater mayfly densities – with more than 70% of production occurring during the wet season. Mayfly production varied between years, decreasing by 5% in TPKFS and 43% in SMR during 1996–97, reflecting lower densities of heptageniids relative to 1995–96. Annual biomass turnover rates (P/B) were high in both sites ranging from 27.2 to 94.6 in TPKFS (Cinygmina sp. and Procloeon sp.) and from 31.8 to 109.8 in SMR (Cinygmina sp. and B. pseudofrequenta). 3. Patterns of daily production in both streams showed that Afronurus sp., Cinygmina sp. and Choroterpes sp. were most productive during the wet season, while Procloeon sp. maintained high production levels throughout the year. The highest daily production of B. pseudofrequenta occurred during the wet season in TPKFS, but in the dry season at SMR. Temporal overlap in production and hence resource utilisation in both streams, calculated using the proportional similarity index (PS), ranged from 0.39 to 0.81. It was highest (0.63–0.81) between pairs of species of Heptageniidae and Baetidae, and lowest between Choroterpes sp. and other mayflies (0.39–0.61). No clear temporal segregation was observed among any species. However, when using the fraction of production attributable to each food, lower PS values were obtained for all species in both sites. In SMR, trophic segregation may have occurred between the two species pairs Procloeon sp.–Cinygmina sp. and Procloeon sp.–Choroterpes sp. (PS=0.17 and 0.03, respectively). 4. A combination of production data and information on the stable isotope signature of mayflies revealed that, during both the wet and dry seasons, more than 50% of total mayfly production in TPKFS was derived from autochthonous foods. In SMR, 68% of production was supported by allochthonous foods during the wet season, and 72% by autochthonous sources in the dry season. Considering that more than 70% of the total production occurred in the wet season, the trophic basis of mayfly production in SMR is mostly allochthonous (58%) while in TPKFS it is mainly of autochthonous origin (66%). The year‐round importance of autochthonous foods in shaded streams such as TPKFS is surprising, but the wet season contribution of allochthonous foods (especially in SMR) may have resulted from depletion of algal biomass during spates.     

Life history and production of Caenis luctuosa (Burmeister) (Ephemeroptera, Caenidae) in two nearby reaches along a small stream

Population dynamics and production of C. luctuosa were compared in two reaches of the Agüera stream (northern Spain). This species showed univoltine winter life history in both sites. However, the start of the recruitment period, and the cohort production interval differed in 1 month between reaches. Secondary production of C. luctuosa ranged from 76 mg m^–2 year^–1 (upper site) to 93 mg m^–2 year^–1 (lower site). Although annual production seemed to be mainly influenced by the biomass found at each site, changes in life history may have also been important. The need to have accurate information about life history of the analysed species at the study sites when assessing secondary production is highlighted.     

Life History and Secondary Production of Mayflies (Ephemeroptera) Indicate Disturbance in Two Small Carpathian Streams

The life histories and the secondary production of 9 mayflies (Ephemeroptera) species were studied at two sites in a submountain stream (West Carpathians, Slovakia). The disturbed site has a deforested and converted to meadows and pastures catchment and the undisturbed one is a well‐preserved submountain stream with 60% of the catchment covered by spruce forests. Differences in the forest cover and in the thermal regime of both streams were reflected in the structural as well as the functional measures. At the undisturbed site, the total secondary production of mayfly community was more than two times higher (3568 mg DW m^–2 y^–1) than at the disturbed site (1446 mg DW m^–2 y^–1). Species could be divided according to their affinity to particular disturbance level. Ecdyonurus picteti, Rhithrogena carpatoalpina, Habrophlebia lauta and Habroleptoides confusa appeared to prefer undisturbed conditions. On the contrary, Ecdyonurus aurantiacus and Habrophlebia fusca occurred only at the disturbed site. The dominant species Baetis rhodani and Electrogena samalorum did not show any clear preference regarding the catchment disturbance. However, nymphs of Electrogena samalorum seem to be more successful at the disturbed site, where they reached bigger body sizes (© 2012 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Egg envelopes of Baetis rhodani and Cloeon dipterum (Ephemeroptera, Baetidae): a comparative analysis between an oviparous and an ovoviviparous species

A comparative ultrastructural investigation on the eggshell (vitelline and chorionic envelopes) has been carried out in the nymphs of two mayfly species encompassed into the Baetidae, namely Baetis rhodani and Cloeon dipterum. During oocyte differentiation in the meroistic telotrophic ovarioles, gametes are connected to discrete nurse cells by trophic cords. In B. rhodani, each ovariole contains several eggs arranged in sequence, whereas in C. dipterum each contains a single egg. Follicle cells are competent for vitelline and chorionic envelope synthesis. Baetis rhodani is an oviparous species and the chorion is fairly thick, formed by an alveolate endochorion and a fibrillar exochorion delimited by a honey‐comb roof. Cloeon dipterum stands out among Ephemeroptera for being ovoviviparous. In B. rhodani, ovulation starts in the older nymphs with dark wing‐pads, whereas in C. dipterum choriogenesis ends in the imaginal stage. Here the chorion is very thin and laid eggs hatch almost immediately, allowing the larvulae to move out. The maturation of a single egg per ovariole is synchronized with the achievement of the adult stage. The acquisition of ovoviviparity has led to remarkable changes in the ovariole organization along with a simplification of the eggshell structure.     

山地河流潜流层大型无脊椎动物群落组成及分布

潜流层大型无脊椎动物是河流生态系统重要的组成部分.2013年8月(夏季)、12月(冬季)和2014年4月(春季),在黑水滩河上游河段,采用人工基质法调查潜流层大型无脊椎动物.结果表明: 3个季节共采集大型无脊椎动物27种,其中夏季22种、冬季和春季各16种,各季节水生昆虫种类所占比例均较高,分别为81.8%、75.0%和62.5%;夏季群落密度显著低于冬季和春季,春季最高;冬季群落生物量显著高于夏季和春季,夏季最低;3个季节群落的物种丰富度指数、Shannon多样性指数和Pielou均匀度指数均没有显著性差异.空间分布上,大型无脊椎动物的密度和丰富度均随潜流层深度增加而呈现降低的趋势,大多数个体均分布在0～20 cm深度.群落以滤食者和收集者组成的集食者为绝对优势功能群.动物的相互作用、生活史策略和潜流层的理化条件影响着潜流层大型无脊椎动物的群落结构和时空分布.