Benthic Macroinvertebrate Community Structure Research Articles

Analyzing Correlations between Stream Benthic Macroinvertebrate Community Structure, Water Quality, and Watershed Land Use in the Continental United States

The objective of this project was to explore national-scale data relationships between land use, primarily variables pertaining to agricultural production, and in-stream biotic conditions in the mainland U.S. Using the Causal Analysis/Diagnosis Decision Information System (CADDIS) and data from the USGS National Water Quality Assessment Program (NAWQA), benthic macroinvertebrate observed versus predicted (O/E) index values were analyzed against a number of land use and habitat variables in 115 sites across the U.S. Constituent loads, or the mass amounts of a chemical constituent entering the waterway per year, were estimated for each site using the USGS LOADEST program and were evaluated with respect to macroinvertebrate O/E and land use values. Relationships between variables, defined causally through CADDIS, were analyzed using simple linear regression to avoid analytical bias. Regression analyses indicated that forest and urban land cover were significantly correlated to macroinvertebrate O/E values (p = 0.0012 and p

Impact of freshwater inputs on the spatial structure of benthic macroinvertebrate communities in two landlocked coastal lagoons

Landlocked lagoons are naturally stressed environments. They are strongly influenced by freshwater input which not only varies naturally, but which is also impacted by anthropogenic activities. This study investigated the direct influence of freshwater discharges on the distribution patterns and abundance of benthic communities in two neighbouring landlocked coastal lagoons, assessing the whole system and the confluence area of each tributary. Sampling occurred in the wet and dry seasons of 2011 at two distances from freshwater discharge locations. Both lagoons were colonized by species from two different pools, freshwater and marine. Freshwater flow rates had a direct influence on the spatial structure of the benthic communities of brackish-water/freshwater interface areas, where also specific taxa can act as early indicators of freshwater input variations. The intensity of this influence is highly dependent on lagoon size, creating spatial heterogeneity or affecting the entire system. The benthic fauna at the confluence of the tributary that depends almost exclusively on groundwater showed the lowest variability, suggesting that the biogeochemical nature of the groundwater may be a central cause for setting specific ecotones. The results suggest that benthic communities of landlocked coastal lagoons can be highly impacted by flow reduction from freshwater aquifers under drought conditions or water abstraction activities.

Responses of stream benthic macroinvertebrate communities to timber harvesting: Best management practices in a low-gradient watershed in Central Louisiana, USA

AbstractForests are the most dominant land-use type in Louisiana, and timber harvesting is the most economically important of the state’s agricultural commodities. Louisiana has developed voluntary best management practices (BMPs) to minimize negative effects of forest operations on stream water quality, but little is known about how aquatic communities inhabiting low-gradient, headwater streams respond to timber harvesting, and if the current BMPs are effective in protecting community structure and function. In 2005, we initiated a multidisciplinary study in the Flat Creek watershed in central Louisiana to discern the effects of timber harvesting activities, with and without BMP implementation, on benthic aquatic macroinvertebrates. During fall 2007, trees were removed adjacent to two headwater streams in the watershed, and benthic macroinvertebrate samples were subsequently collected at seven stream locations seven times between 2006 and 2009. Our objectives were to describe the community structure of benthic macroinvertebrates in low-order, low-gradient streams, how macroinvertebrate communities responded to timber harvest operations, and whether significant changes in community structure were evident under different levels of BMP implementation. The community structure was predominantly generalist taxa including chironomids, sphaeriid bivalves and asellid isopods. Analyses of variance demonstrated significant increases in bivalve abundance and decreases in the abundance of malacostracan and shredding taxa at most of the sampling sites downstream of BMP-implemented harvest locations in the spring. Additionally, significant increases in bivalves were also found at two sites during late summer. Our results suggest that timber harvesting activities, regardless of BMP implementation, had limited shortterm impacts on resident macroinvertebrates in these lowgradient, subtropical streams. Continued monitoring at the study sites will allow us to better understand the longterm effects of timber harvesting in these stream systems, particularly the resilience of stream biota to harvestingrelated stream conditions.

Does hydrological connectivity determine the benthic macroinvertebrate structure in oxbow lakes?

AbstractIn this study, we analyse the qualitative and quantitative structure of benthic macroinvertebrate communities in three oxbow lakes differing in hydrological connectivity, located along the lowland Łyna River (NE Poland). The lakes differed in the extent of surface contact with the main river channel and represented lotic, semi‐lotic, and lentic types of water bodies. Mean benthofauna density ranged from 0.9 · 103 (lentic) to 2.0 · 103 indiv. m−2 (semi‐lotic) and mean biomass ranged from 16 (lentic) to 202 gww m−2 (semi‐lotic); these differences were not statistically significant (P ≤ 0.05). The diversity (Shannon's index) was highest in the lotic and lowest in the lentic ecosystem. It was predominated by Oligochaeta and Chironomidae larvae. The highest, statistically significant differences were observed between the densities of Ephemeroptera larvae (P ≤ 0.05), Megaloptera larvae (P ≤ 0.05) and Arachnida (P ≤ 0.01). In terms of biomass, gastropods prevailed in the semi‐lotic, bivalves in the lotic and Chironomidae larvae in the lentic ecosystems. Amongst gastropods, Viviparus viviparus L. dominated in oxbows connected with the river. Our results, supported by the canonical correspondence analysis (CCA) and hierarchical cluster analysis showed a significant effect of hydrological connectivity, which in a direct or indirect way influenced the macroinvertebrate structure in oxbow lakes. As shown by CCA, a free exchange of water between oxbows and the river channel promotes favourable conditions for the development of hydrobionts. Copyright © 2015 John Wiley & Sons, Ltd.

Seasonal variation of allochthonous and autochthonous energy inputs in an alpine stream

Despite the enormous importance of alpine streams, information about many aspects of their ecology is still insufficient. Alpine lotic systems differ in many environmental characteristics from those lower down, for example because above tree line streams drain catchments where terrestrial vegetation is scarce and allochthonous organic input is expected to be small. The main objectives of this study were to examine seasonal variation of autochthonous and allochthonous energetic inputs and their relationship with macroinvertebrate communities in the Po river, an alpine non-glacial stream (NW Italy). For one year, samplings were monthly performed in a homogeneous 100 m stream reach for discharge, autochthonous energy input (benthic chlorophyll a ), allochthonous energy input (coarse particulate organic matter), abundance and structure of benthic macroinvertebrate community. Chlorophyll a concentrations were in the range of what reported for other alpine streams, but presented a time-lag with respect to what has been reported for glacial-fed mountain rivers. CPOM amounts were lower than those in lowland, forested streams of the same area but exhibited an intriguing, different seasonal variability, probably reported for the first time, with a maximum in spring and a minimum in winter. We collected 29,950 macroinvertebrates belonging to 13 families and 10 orders. Benthic communities were essentially dominated by Ephemeroptera, Plecoptera and Diptera. Scrapers was the most important FFG, but also Shredders were well represented. Relationships between chlorophyll a concentrations, CPOM availability and macroinvertebrate community characteristics were analysed and discussed considering the existence of different top-down or bottom-up regulation mechanisms. This study confirms that benthic algae constitute an essential resource for macroinvertebrates in alpine streams above the tree line but also underlines the importance of terrestrial organic input, a previously neglected input in environments above the tree line. The major forces shaping energetic inputs and invertebrate communities seemed to be related to the Alpine climate, and especially to snow accumulation and melting, with the consequent substantial discharge variations.

On the relationship between the diversity and structure of benthic macroinvertebrate communities and sediment enrichment with heavy metals in Gabes Gulf, Tunisia

The variations in the composition and structure of macroinvertebrate benthic communities in relationship with the marine sediment enrichment with heavy metals were investigated in the Gulf of Gabes, Tunisia. Standard community parameters as well as the trophic and ecological structure were analysed in 18 stations sampled in six localities. Highest values of diversity descriptors (S, N and H′) were recorded in the less-polluted localities and vice versa. Besides, the results of AMBI and BENTIX indexes were also concordant with those obtained with the classical diversity parameters and matched with the sediment heavy metals distribution in the Gulf of Gabes. Compared with the northern and southern parts of the Gulf, the central area was found to be the most polluted and to host the most-affected benthic community. In addition, biotic indexes were found to be very useful tools to monitor the ecological quality status of benthic assemblages.

Interim Responses of Benthic and Snag‐Dwelling Macroinvertebrates to Reestablished Flow and Habitat Structure in the Kissimmee River, Florida, U.S.A.

AbstractA critical component in the effort to restore the Kissimmee River ecosystem is the reestablishment of an aquatic invertebrate community typical of free‐flowing rivers of the southeastern United States. This article evaluates early responses of benthic and snag‐dwelling macroinvertebrates to restoration of flow and habitat structure following Phase I construction (interim period) of the Kissimmee River Restoration Project. Replicate benthic and snag samples were collected from remnant river channels in Pool A (Control site), and Pool C, the site of the first phase of restoration (Impact site). Samples were collected quarterly for 2 years prior to construction (baseline) and monthly or quarterly for 3 years following Phase I construction and restoration of flow. Baseline benthic data indicate a community dominated by taxa tolerant of organic pollution and low levels of dissolved oxygen, including the dipterans Chaoborus americanus (Chaoboridae) and the Chironomus/Goeldichironomus group (Chironomidae). Baseline snag data indicate a community dominated by gathering‐collectors, shredders, and scrapers. Passive filtering‐collector invertebrates were rare. Following restoration of flow, benthic invertebrate communities are numerically dominated by lotic taxa, including bivalves and sand‐dwelling chironomids (e.g. Polypedilum spp., Cryptochironomus spp., and Tanytarsini). Snags within the Phase I area support an invertebrate community dominated by passive filtering‐collectors including Rheotanytarsus spp. (Chironomidae) and Cheumatopsyche spp. (Hydropsychidae). Results indicate that restoration of flow has resulted in ecologically significant changes to the river habitat template not observed in Pool A. Observed shifts in benthic and snag macroinvertebrate community structure support previously developed hypotheses for macroinvertebrate responses to hydrologic restoration.

Assessment of Endocrine-Disrupting Chemicals Attenuation in a Coastal Plain Stream Prior to Wastewater Treatment Plant Closure

The U.S. Geological Survey is conducting a combined pre/post-closure assessment at a long-term wastewater treatment plant (WWTP) site at Fort Gordon near Augusta, Georgia. Here, we assess select endocrine-active chemicals and benthic macroinvertebrate community structure prior to closure of the WWTP. Substantial downstream transport and limited instream attenuation of endocrine-disrupting chemicals (EDCs) was observed in Spirit Creek over a 2.2-km stream segment downstream of the WWTP outfall. A modest decline (less than 20% in all cases) in surface water detections was observed with increasing distance downstream of the WWTP and attributed to partitioning to the sediment. Estrogens detected in surface water in this study included estrone (E1), 17β-estradiol (E2), and estriol (E3). The 5 ng/l and higher mean estrogen concentrations observed in downstream locations indicated that the potential for endocrine disruption was substantial. Concentrations of alkylphenol ethoxylate (APE) metabolite EDCs also remained statistically elevated above levels observed at the upstream control site. Wastewater-derived pharmaceutical and APE metabolites were detected in the outflow of Spirit Lake, indicating the potential for EDC transport to aquatic ecosystems downstream of Fort Gordon. The results indicate substantial EDC occurrence, downstream transport, and persistence under continuous supply conditions and provide a baseline for a rare evaluation of ecosystem response to WWTP closure.

Global warming effects on benthic macroinvertebrates: a model case study from a small geothermal stream

The aim of this study was to predict global warming effects on benthic macroinvertebrate community structure by using a small temperate geothermal stream as a model system. We collected benthic macroinvertebrates, measured physical and chemical water properties at eight localities up the Kudoski stream steep water temperature gradient, and used 11 metrics and indexes to characterize community structure. Species richness and evenness decreased, but total abundance increased with the increase of average annual water temperature (t av), with species richness being most and total abundance least sensitive to this parameter. The increase of Gastropoda relative abundance and the decrease of Ephemeroptera, Plecoptera and Trichoptera richness, respectively, were the earliest responses of taxonomic groups to t av increase. Relative abundance of Orthocladiinae decreased and that of Chironomini increased with the increase of t av. This indicates that Chironomidae are not reliable predictors of global warming effects in running waters, and that lower taxonomic levels, subfamily or tribe, are more suitable for that purpose. Changes in community structure did not linearly follow t av increase, since a great community shift was observed at t av ≈ 20°C indicating that present trends of community responses to changes in climatic conditions should not be linearly extrapolated to future warming.

설악산 양사면 하천에서의 고도차에 따른 저서성 대형무척추동물 군집의 공간 분포

There are marked differences in climate condition between east-facing slopes and west-facing slopes in Mt. Seorak (1,708 m). This study was conducted to find out the differences of benthic macroinvertebrate communities between both slopes of Mt. Seorak. Quantitative (Surber net; <TEX>$30cm{\times}30cm$</TEX>, mesh: 1mm) and qualitative (Hand net; mesh: 1mm) samplings ware carried out seasonally in each site which had 100-meter-high difference from November 2010 to November 2011. Most of the survey sites showed sound environmental conditions because they were located in the protection area of the national park. The benthic macroinvertebrates collected from all survey sites were composed of 158 species, 62 families, 17 orders, 7 classes and 5 phyla. DCA (Detrended Correspondence Analysis) ordination based on the abundance of benthic mactoinvertebrates showed that altitude was a major factor governing the structure of benthic macroinvertebrate community. There was no significant difference of the communities between both slopes.

Timiş River (Banat, Romania) Benthic Macroinvertebrate Communities Structure Spatial Dinamic

ABSTRACT This study presents the description of the structure of benthic macroinvertebrate communities of the Timiș River (Danube Watershed) in correlation with environmental parameters. The results are based on quantitative benthic macroinvertebrates (105 samples) taken in 2011 (June-September) from 21 stations of the the Timiş River, situate between its sources and the Romanian-Serbian border (241 km). The assessed biotope variables were: altitude, slope, riverbed width, depth, substratum types, channel modification and water physico-chemical caracteristics. The results of the study reveal that the spatial structure of benthic macroinvertebrates is induced by the substrate type, by the minor riverbed modifications in comparison with the natural conditions and the quantities of oxidable matters in the water.

Effects of pine plantations on structural and functional attributes of forested streams

In low-order forested streams, watershed-scale land-use modifications, such as the replacement of native vegetation by conifer monocultures, can affect energy inputs into streams and trophic interactions within these donor-controlled food webs. We examined the effects of Pinus radiata plantations on structural (benthic macroinvertebrate communities) and functional (alder and pine leaf-litter breakdown) attributes of headwater streams. We compared three streams draining pine plantations with three draining natural deciduous forests. We found differences in the structure of benthic macroinvertebrate communities, namely lower densities of shredders in streams flowing through pine plantations. Breakdown rates of alder leaves was a 20% lower in streams draining pine plantations, and breakdown of pine needles, a much lower quality material, was slower than that of alder and did not differ between stream types. Although fungal activity was similar in all streams, lower detritivore densities under pine plantations could explain the lower rate of alder breakdown in these environments. The present study points out that pine monocultures alter the structure of benthic macroinvertebrate communities and reduce detritus processing capacity of streams. However, these effects were weaker than expected due to the presence of deciduous riparian forest in pine streams.

Benthic macroinvertebrate community structure and seasonal variation in a neotropical stream in the State of Alagoas, Brazil

This paper presents a study on the macrobenthic community in the Salvia stream, a headwater stream that runs through a conserved Atlantic forest fragment in the state of Alagoas, Brazil, and identifies the environmental factors that most influence the community structure. Ten sampling sites were chosen, conducting each collection during the rainy season of 2010 and the dry season of 2011. At each site the macroinvertebrates were collected using a D net (0.250 mm mesh). Water samples were collected and taken to the laboratory to analyze Dissolved Oxygen, Conductivity, pH and Alkalinity. Water temperature, surface current speed and depth were measured at the site. Canonical Correspondence was used to analyze the effect of environmental factors on the macroinvertebrate community. All the environmental factors measured showed significant variation between seasons, showing the seasonality effects on the stream environment. Eighteen taxa were identified, with predominance of Palaemonidae (Decapoda) and Chironomidae (Diptera), respectively, during the rainy and dry season. The results showed that the macroinvertebrates were more correlated to pH, Alkalinity and Dissolved Oxygen, indicating that this ecosystem variation is mainly based on the organic matter decomposition process.

서울 당현천의 저서무척추동물상과 수생태 건강성 평가

The present study was performed to examine the aquatic ecosystem health assesment and community structure of Benthic Macroinvertebrates at Danghyun Stream in Seoul on April 29 to November 21, 2012. Total taxa of Benthic Macroinvertebrates were 63 species, 30 families, 13 orders and 6 classes in 4 phyla. All of them, non-insects were composed of 3 species in Annelida, 2 species in Mollusca, 1 species in Platyhelminthes and 1 species in Crustacea. Aquatic insects were composed of 17 species in Diptera, 16 species in Ephemeroptera, 14 species in Trichoptera, 3 species in Plecoptera, 3 species in Odonata, 1 species in Hemiptera, 1 species in Megaloptera and 1 species in Coleoptera respectively. Occurrence species was 43 species at upper site(site 1) and 15～21 species at restoreation water area(site 2～site 4). Major dominant species at site 1 was Semisulcospira liberta, simulium sp.1 and Glossoma KUa which are considered as clean water indicaters, dominant species at middle and lower area was Chironomidae sp. and Baetis fuscatus which are considered as somewhat pollution indicators. Species diversity index and species richness index were 3.54 and 3.29 at upper site, 2.26～2.53 and 1.60～1.81 at middle and lower area. Benthic Macroinvertebrates index was 90.2 at site 1, 44.1 at site 2, 53.1 at site 3 and 61.6 at site 4. Aquatic ecosystem health by Benthic Macroinverbrates index was very good level at site 1, good level at site 4, fair level at site 3 and poor level at site 2 respectively. Therefore, the results shows that site 1 is more stable Benthic Macroinvertebrate community structure than restoration water area at Danghyun Stream in Seoul.

Response of benthic macroinvertebrates to whole-lake, non-native fish treatments in mid-elevation lakes of the Trinity Alps, California

Introduced fish reduce the abundance and diversity of native aquatic fauna, but the effect can be reduced in complex habitats. We manipulated fish populations in forested mountain lakes to determine whether or not fish affected benthic macroinvertebrate composition across lakes with differing habitat complexity. We compared abundance, biomass, body-length, and community structure of benthic macroinvertebrates from 16 lakes with three treatments (fish stocked, suspended stocking, fish removed) and unstocked fishless “controls”. Over 4 years, we assessed the relative importance of fish and environmental variables influencing the composition of benthic macroinvertebrates. Control lakes had the greatest overall abundance of macroinvertebrates when chironomid midges were excluded. Abundances of insects in the clinger/swimmer functional group and caddisflies were greatest in the control lakes but were primarily influenced by habitat variables including the availability of aquatic vegetation and wood. Total biomass and mean body length of macroinvertebrates were not affected by treatment. Taxon richness of macroinvertebrates was about 40% greater in the control lakes compared to the treatment lakes but did not differ among treatments. Our results suggest that fish reduce susceptible macroinvertebrate richness and abundances, but that changes associated with alterations of fish composition are confounded by other factors in complex lake habitats.

Are Toronto’s streams sick? A look at the fish and benthic invertebrate communities in the Toronto region in relation to the urban stream syndrome

Impacts of urbanization on aquatic ecosystems are intensifying as urban sprawl spreads across the global land base. The urban stream syndrome (USS) identifies "symptoms" associated with urban development including changes in biotic communities, hydrology, water chemistry, and channel morphology. Direct relationships between road density (as surrogate of urbanization) and indicators of the USS were identified for streams in the Toronto region. Significant negative relationships were revealed between road density and biological (fish and benthic macroinvertebrate) richness, diversity, and fish Index of Biotic Integrity scores. Significant positive relationships were found between road density and tolerant fish/benthic macroinvertbrates, benthos Family Biotic Index scores, mean summer stream temperature, stream flashiness, and several water quality variables. Analysis of biological data showed that only four fish species and a reduced number of benthic macroinvertebrate families remained at the most urbanized sites. Road density was found to be a major determinant in both the fish and benthic macroinvertebrate community structure.

Interactions between invading benthivorous fish and native whitefish in subarctic lakes

Summary Many species are expanding their distribution towards higher latitudes and altitudes in response to climate change. These range shifts are expected to change fish community structure and alter food‐web dynamics in subarctic lakes. However, the impacts of invading species on native fish and invertebrate prey communities remain understudied. The trophic ecology of invasive species determines the likelihood of direct resource competition with native taxa. In Northern Europe, perch (Perca fluviatilis), a trophic generalist, and ruffe (Gymnocephalus cernuus), a benthic specialist, are expanding their distribution ranges northwards, colonising lakes inhabited by a native generalist, whitefish (Coregonus lavaretus). We predicted that increased fish diversity and density would deplete the invertebrate community and increase resource competition between native and invasive species. To assess the degree of resource competition between native and invasive species, we compared (i) fish and invertebrate community structure; (ii) diet and stable carbon and nitrogen ratios of whitefish, ruffe and perch and (iii) growth, condition and relative population size of whitefish in two non‐invaded lakes with two lakes containing one and two lakes containing both invasive species. Each lake was sampled on a single occasion between August and September. Benthic macroinvertebrate density and community structure were unaffected by increased consumer diversity, while top‐down control of pelagic zooplankton density and size was evident in lakes with increased fish diversity. Differences in diet and stable isotope ratios were evident between all whitefish populations, although these were not directly related to the presence of invasive species. Specialised adaptations of invasive species may confer a competitive advantage in invaded lakes; ruffe dominated the profundal niche, while perch displayed an ontogenetic shift to piscivory, reducing niche overlap with native whitefish. Growth rate and population density of whitefish were largely independent of fish community structure and were governed by local variations in lake productivity. However, there was a sign of lowered condition of whitefish in invaded systems. Shallow and more productive lakes with higher food availability supported populations of native and invasive species. Our findings indicate that trophic specialisations of invasive species play a key role in determining their impacts on the systems they invade. This study focussed on early stages of invasion, and the outcome of species interactions may change following the establishment of new species. In addition, these impacts will not be uniform across the invaded landscape as lake‐specific variations in morphometry and resource availability will alter the competitive balance between native and invasive species.

Harvesting an invasive bivalve in a large natural lake: species recovery and impacts on native benthic macroinvertebrate community structure in Lake Tahoe, USA

ABSTRACT The increasing dispersal and establishment of aquatic invasive species in natural freshwater ecosystems has led to efforts to remove non‐native taxa and/or restore native species. An invasive bivalve, Asian clam (Corbicula fluminea), recently (2002) became established in a large, natural subalpine lake (Lake Tahoe, USA). In 2009, experimental efforts were undertaken to harvest C. fluminea from Lake Tahoe sediments using a manually operated suction dredge apparatus. Treatment and control plots were monitored for a 450 day period after dredging to observe target species (C. fluminea) and non‐target macroinvertebrate recovery rates. A paired Before‐After‐Control Impact analysis was used to assess the short‐ and long‐term impacts of suction dredging. Physical harvest resulted in short‐term reductions of C. fluminea (1500 individuals m‐2 before treatment to 60 individuals m‐2 14 days after treatment) with significant disruption to benthic macroinvertebrate community structure. The impact to the target invasive species (C. fluminea) was present 450 days after treatment and community diversity (as represented by Simpson diversity index) did not recover after 1 year (365 days) in dredged sites. Certain non‐target macroinvertebrate taxa (Chironomidae and native clam (Pisidium spp.)) increased in suction dredge plots to levels greater than before treatment or in control plot conditions at the end of the study period. Harvesting C. fluminea significantly reduced population densities for a period of 450 days after the removal. Recolonization rates of C. fluminea and non‐target species over multiple reproductive seasons will determine the feasibility for this method as a long‐term control strategy. Copyright © 2012 John Wiley &amp; Sons, Ltd.

경북 주흘산 일대 수계의 저서무척추동물 군집

This study was performed to examine the community structure of benthic macroinvertebrates at Water System of Mt. Juheul and its nearby area on August 21 and 21, 2011. Total taxa of benthic macroinvertebrates were 49 species, 26 families, 12 orders, 6 classes in 5 phyla. Aquatic insects were composed of 14 species in ephemeroptera, 12 species in trichoptera, 9 species in diptera, 3 species in plecoptera, 1 species in odonata, 1 species in hemiptera and 1 species in coleoptera. Other non-insects were composed of 3 species in annelida, 1 species in platyhelminthes, 1 species in nematomorpha and 1 species in mollusca. Indicator species in clean waters were Dugesia japonica in platyhelminthes, Drunella cryptomeri, Ephemerella denta in ephemeroptera, Nemoura KUa, Paragnetina flavotincta, Kamimuria KUa in plecoptera and Neonectes natrix in coleoptera. Occurrence species of benthic macroinvertebrates at each survey site at Mt. Juheul and its nearby area were 15～28 species and, individual numbers of those were 62～223 individuals/0.27m2. Species diversity indices and species richness indices of benthic macroinvertebrates were 2.59～4.07 and 3.18～4.99.

Water quality and benthic macroinvertebrate communities in karst landscapes of North Island, New Zealand: influences of water sources, habitat type and anthropogenic disturbances

In karst landscapes, aquatic habitats differ in terms of the relative contributions of different water sources (allogenic surface stream vs autogenic karst groundwater) and their geomorphology. Benthic macroinvertebrate community structure in these habitats is likely to vary in response to this heterogeneity, as well as to the physicochemical differences between water flowing through pasture vs native forest dominated catchments. Surveys were conducted to examine the influences of water source, habitat type (main stream-ways and side passages in caves, and epigean springs) and surrounding land use (native forest or pasture) on the water quality and benthic community structure in the Maniapoto Karst, North Island, New Zealand. Generally, springs and cave side passages received more autogenic water, indicated by lower temperatures and higher conductivities, than the main stream-ways of caves. However, in terms of community structure, the epigean springs and cave side passages were most distinct from each other, whilst the main stream-ways of caves were intermediate between the other two habitats. Temperature and nitrate concentrations were higher in sites surrounded by pasture than those in native forest, but surrounding land use exerted less influence on macroinvertebrate community structure than habitat type. A comparison of community structure in caves with high and low tourist traffic failed to identify any significant effects.