Presence Of Macroinvertebrates Research Articles

Amphibian loss alters periphyton structure and invertebrate growth in montane streams.

Amphibians are declining worldwide due to a combination of stressors such as climate change, invasive species, habitat loss, pollution and emergent diseases. Although their losses are likely to have important ecological consequences on the structure and functioning of freshwater ecosystems, this issue has been scarcely explored. We conducted an experiment in three montane streams-where primary production is the main source of energy and carbon-to assess the effects of amphibian disappearance (i.e. presence or absence of the common midwife toad Alytes obstetricans, a common species found in pools of these streams) on several aspects of ecosystem functioning and structure: periphyton biomass and chlorophyll a concentration, algal assemblage structure, and growth of macroinvertebrate grazers. We compared four types of experimental enclosures: (i) without macroinvertebrates or amphibians; (ii) with larvae of the caddisfly Allogamus laureatus; (iii) with A. obstetricans tadpoles; and (iv) with both A. laureatus larvae and A. obstetricans tadpoles. The absence of tadpoles increased periphyton biomass, but did not cause differences on inorganic sediment accrual. The algal assemblage had a higher diversity in the absence of tadpoles, and their characteristic taxa differed from the assemblages in presence of tadpoles. A. laureatus presented higher mass in presence of tadpoles; however, tadpole length was not affected by presence of macroinvertebrates. Our results suggest that presence of tadpoles is a driver of periphyton accrual and assemblage structure, acting as top-down control and with key potential consequences on the functioning of montane stream ecosystems.

Influence of Suspended Mussel Aquaculture and an Associated Invasive Ascidian on Benthic Macroinvertebrate Communities

Many benthic macroinvertebrates are associated with cultured bivalves but are normally excluded from studies on the environmental effects of bivalve aquacultures. We evaluated the hypothesis that mussel aquaculture increases overall “benthic” macroinvertebrate productivity by considering both sediment- and mussel sock-associated macroinvertebrates. It was predicted that the presence of the invasive ascidian Styela clava would increase this effect by increasing the mussel sock’s biogenic structure. Macroinvertebrates in sediments and on mussel socks were sampled in eight bays on Prince Edward Island, Canada: three were invaded by Styela clava and there were five where it was absent. Infaunal macroinvertebrates associated with benthic sediments (sediment macroinvertebrates) within leases were less abundant relative to the control locations outside of leases and showed a trend towards decreased biomass and productivity. Abundance of mussel sock-associated macroinvertebrates was greater in bays with S. clava than in bays without it. When sediment and mussel sock macroinvertebrates were considered together as “benthic” communities within mussel leases and compared to sediment macroinvertebrate communities outside of leases, “benthic” macroinvertebrate abundance, biomass, and productivity were greater inside mussel leases than in areas outside of them. The presence of S. clava did not influence this trend. Although the ecological role of the macroinvertebrates associated with suspended mussels is likely not equivalent to those associated with benthic sediments, the presence of macroinvertebrates on suspended mussels, in some measure, offsets the impacts on the abundance, biomass, and productivity of macroinvertebrate communities at the farm-scale.

The Biotic Integrity of Ciliwung River in West Java Under Multiple Urban Stressors

Based on its imperviousness, most of the sub-watersheds in the lower part of Ciliwung watershed in West Java are classified as urban drainage. High imperviousness in the urban environment will cause multiple stressors among others on the discharge, water quality and habitat condition, those supposedly support the presence of macroinvertebrates. Macroinvertebrates are commonly used as markers of the biotic integrity of aquatic ecosystem. The aim of the study is to explore the extent of causal relationship between imperviousness, as trigger for the emergence of stressors on biotic integrity, which is represented by Family Biotic Index. The Family Biotic Index is considered as response variables, while imperviousness, discharge, water quality and habitat condition are as explanatory variables. Significance correlation tests among explanatory and response variables from 23 sub-watersheds of Ciliwung using Spearman Rank-order Correlation show that they are correlated. Influence of multiple urban stressors on the biotic integrity was assessed using several alternatives of multiple linear regression model, which is determined based on backward elimination procedure. The standard error of estimate ranges between 0.8563 and 0.9096 are less than standard deviation amounted 1.0876, therefore the models are acceptable for predicting the response variable, the FBI. Although they have not yet fully represented the observed FBI values, especially for the lowest and the highest one, possibly due to very limited data. This can be seen from the low value of the coefficient of determination, R2 ranging from 33,23% up to 43.86%, and from the juxtaposed between model results and the observed values.

Leaf Nutrients and Macroinvertebrates Control Litter Mixing Effects on Decomposition in Temperate Streams

Plant litter decomposition is an essential ecosystem function in temperate streams. Both riparian vegetation and decomposer communities are major determinants of the decomposition efficiency and the interactions occurring within litter mixtures. However, the extent to which such litter mixture interactions are affected by combined shifts in litter traits and decomposer community is not well understood. We used leaf litter from 10 European tree species in order to study litter decomposition and litter mixture effects occurring in two-species litter mixtures in a temperate forested stream of northwestern France. The study distinguished between (1) decomposition involving microorganisms alone or together with invertebrates, and (2) decomposition involving litter mixtures of similar or dissimilar nutrient content. Increasing mean litter nutrient concentration favored both microbial activity and litter decomposition rate. Surprisingly, the highest litter mixture effects occurred in mixtures containing two nutrient-rich litters and occurred mainly in macroinvertebrate presence. Both the “mass ratio hypothesis,” expressed as the community-weighted mean traits (TraitCWM), and the “niche complementarity hypothesis,” expressed as the functional dissimilarity of litter traits (TraitFD), contributed to explain litter mixture effects. However, TraitCWM was found to be a better predictor than TraitFD. Finally, when evaluating the individual contributions of litter nutrients, calcium and magnesium appeared as important drivers of litter mixture effects. Our findings suggest that the mass ratio hypothesis overrules the niche complementarity hypothesis as a driver of litter diversity effects. Our study highlights the key importance of macroinvertebrates and of leaf nutrients, such as Ca and Mg, which are often neglected in decomposition studies in streams.

Growth of pioneer beach plants is strongly driven by buried macroalgal wrack, whereas macroinvertebrates affect plant nutrient dynamics

Sandy beach food webs depend heavily upon marine organic input, such as macroalgae, as internal organic matter productivity is low. The fate, however, of this marine organic material (termed wrack) after being deposited onto the beach and its relation to pioneer vegetation, consisting of annual and perennial beach plants, needs to be further elucidated. In particular, the effect of various drivers, such as wrack burial and macroinvertebrate presence, on wrack decomposition is largely unknown on sandy beaches. Also, the subsequent effects of decomposition-driven nitrogen and phosphorus availability on beach pioneer plant growth are not yet understood. We performed a mesocosm experiment manipulating Fucus vesiculosus wrack access to the supratidal amphipod Talitrus saltator, and used Cakile maritima and Elytrigia juncea as phytometers to estimate decomposition-driven, wrack-derived nutrient supply. Buried wrack had a strong positive effect (2–3 fold increase) on plant mass, N and P content of C. maritima compared to surface wrack, while effects on E. juncea were largely absent. In addition, macroinvertebrate-facilitated decomposition was important for increasing nutrient availability, but this did not result in an increase in plant growth. We conclude that the burial of wrack by a thin layer of sand is a crucial driver of beach pioneer plant growth, which is most likely due to an increase in moisture availability. This supports the importance of management practices that allow deposited wrack to remain and be buried on the sandy beach for a long period of time, which will have positive effects on beach pioneer plant growth and possibly embryo dune formation.

Soil Macroinvertebrate Presence Alters Microbial Community Composition and Activity in the Rhizosphere.

Despite decades of research, our understanding of the importance of invertebrates for soil biogeochemical processes remains incomplete. This is especially true when considering soil invertebrate effects mediated through their interactions with soil microbes. The aim of this study was to elucidate how soil macroinvertebrates affect soil microbial community composition and function within the root zone of a managed grass system. We conducted a 2-year field mesocosm study in which soil macroinvertebrate communities were manipulated through size-based exclusion and tracked changes in microbial community composition, diversity, biomass and activity to quantify macroinvertebrate-driven effects on microbial communities and their functions within the rhizosphere. The presence of soil macroinvertebrates created distinct microbial communities and altered both microbial biomass and function. Soil macroinvertebrates increased bacterial diversity and fungal biomass, as well as increased phenol oxidase and glucosidase activities, which are important in the degradation of organic matter. Macroinvertebrates also caused distinct shifts in the relative abundance of different bacterial phyla. Our findings indicate that within the rhizosphere, macroinvertebrates have a stimulatory effect on microbial communities and processes, possibly due to low-intensity microbial grazing or through the dispersal of microbial cells and spores by mobile invertebrates. Our results suggest that macroinvertebrate activity can be an important control on microbially-mediated processes in the rhizosphere such as nitrogen mineralization and soil organic matter formation.

Fate and effects of sediment-associated triclosan in subtropical freshwater microcosms

Triclosan (TCS) is an antibacterial agent that is commonly used in personal care products. Because of its sediment-binding properties, TCS exposure presents a potential threat to sediment-dwelling aquatic organisms. Currently our knowledge of the fate and effects of sediment-associated TCS in aquatic systems is limited. To understand the impact of sediment-associated TCS, we used microcosms to assess effects of TCS exposure on a diverse range of organisms selected to mimic a subtropical community, with an exposure period of 28 days. We included the oligochaete freshwater worm Limnodrilus hoffmeisteri to evaluate the interaction between sediment-associated TCS and sediment-dwelling organisms, including potential loss of TCS from the sediment due to biological activity and bioaccumulation. Benthic macroinvertebrate presence significantly increased the TCS levels from 0.013 ± 0.007 μg/L to 0.613 ± 0.030 μg/L in the overlying water through biological activity, posing a potential additional risk to pelagic species, but it did not result in a significant reduction of the sediment concentration. Furthermore, worms accumulated TCS with estimated Biota-Sediment-Accumulation-Factors (BSAFs) ranging between 0.38–3.55. Other than for algae, TCS at environmental concentrations did not affect the survival of the introduced organisms, including the L. hoffmeisteri. Our results demonstrate that, although TCS at currently detected maximum concentration may not have observable toxic effects on the benthic macroinvertebrates in the short term, it can lead to bioaccumulation in worms.

The inland water macro-invertebrate occurrences in Flanders, Belgium.

The Flanders Environment Agency (VMM) has been performing biological water quality assessments on inland waters in Flanders (Belgium) since 1989 and sediment quality assessments since 2000. The water quality monitoring network is a combined physico-chemical and biological network, the biological component focusing on macro-invertebrates. The sediment monitoring programme produces biological data to assess the sediment quality. Both monitoring programmes aim to provide index values, applying a similar conceptual methodology based on the presence of macro-invertebrates. The biological data obtained from both monitoring networks are consolidated in the VMM macro-invertebrates database and include identifications at family and genus level of the freshwater phyla Coelenterata, Platyhelminthes, Annelida, Mollusca, and Arthropoda. This paper discusses the content of this database, and the dataset published thereof: 282,309 records of 210 observed taxa from 4,140 monitoring sites located on 657 different water bodies, collected during 22,663 events. This paper provides some background information on the methodology, temporal and spatial coverage, and taxonomy, and describes the content of the dataset. The data are distributed as open data under the Creative Commons CC-BY license.

Warming weakens facilitative interactions between decomposers and detritivores, and modifies freshwater ecosystem functioning.

Warming is among the major drivers of changes in biotic interactions and, in turn, ecosystem functioning. The decomposition process occurs in a chain of facilitative interactions between detritivores and microorganisms. It remains unclear, however, what effect warming may have on the interrelations between detritivores and microorganisms, and the consequences for the functioning of natural freshwater ecosystems. To address these gaps, we performed a field experiment using tank bromeliads and their associated aquatic fauna. We manipulated the presence of bacteria and detritivorous macroinvertebrates (control, "bacteria," and "bacteria+macroinvertebrates") under ambient and warming scenarios, and analyzed the effects on the microorganisms and ecosystem functioning (detritus mass loss, colored dissolved organic matter, and nitrogen flux). We applied antibiotic solution to eliminate or reduce bacteria from control bromeliads. After 60days incubation, bacterial density was higher in the presence than in the absence of macroinvertebrates. In the absence of macroinvertebrates, temperature did not influence bacterial density. However, in the presence of macroinvertebrates, bacterial density decreased by 54% with warming. The magnitude of the effects of organisms on ecosystem functioning was higher in the combined presence of bacteria and macroinvertebrates. However, warming reduced the overall positive effects of detritivores on bacterial density, which in turn, cascaded down to ecosystem functioning by decreasing decomposition and nitrogen flux. These results show the existence of facilitative mechanisms between bacteria and detritivores in the decomposition process, which might collapse due to warming. Detritivores seem to contribute to nutrient cycling as they facilitate bacterial populations, probably by increasing nutrient input (feces) in the ecosystem. However, increased temperature mitigated these beneficial effects. Our results add to a growing research body that shows that warming can affect the structure of aquatic communities, and highlight the importance of considering the interactive effects between facilitation and climatic drivers on the functioning of freshwater ecosystems.

Leaf litter decomposition on insular lentic systems: effects of macroinvertebrate presence, leaf species, and environmental conditions

The decomposition of leaf litter of terrestrial origin is a fundamental process in aquatic ecosystems in forest contexts. Little is known about what drives leaf litter decomposition in oceanic islands. We examined the relative importance of leaf litter identity (Acacia melanoxylon, Pittosporum undulatum, Morella faya) and environmental conditions on litter decomposition in seven lakes in the oceanic archipelago of Azores for 28 and 56 days. Leaf litter was incubated in coarse and fine mesh bags for the assessment of the relative contribution of macroinvertebrates to leaf litter decomposition. Leaf litter mass loss generally did not differ between mesh sizes, suggesting that in these lakes macroinvertebrates generally have a negligible role on leaf decomposition. Leaf litter decomposition was in the order M. faya < A. melanoxylon < P. undulatum. A negative correlation was found between leaf litter mass loss and lignin concentration. Mass loss of P. undulatum was related to lake elevation and chlorophyll a (taken as surrogates for water temperature and dissolved nutrient availability, respectively), whereas mass loss of M. faya was related to chlorophyll a on day 56. These results suggest that changes in the composition of the leaf litter input and environmental conditions can affect leaf litter decomposition in Azorean lakes, with potential consequences for nutrient cycling.

Effects of experimental warming, litter species, and presence of macroinvertebrates on litter decomposition and associated decomposers in a temperate mountain stream

Small woodland streams make the majority of water courses in most watersheds. Litter decomposition is a key ecosystem process in these shaded streams, and its response to warming can have profound consequences for food webs and the carbon (C) cycle. However, these responses can be modulated by litter identity and the structure of the detrital food web. Here we report on a manipulative study aiming at evaluating the effects of warming (+2.8 °C), litter identity (chestnut (Castanea sativa) or oak (Quercus robur) litter), and the structure of the detrital food web (presence or absence of macroinvertebrates) on litter decomposition and decomposers in a small, temperate woodland stream. Warming significantly stimulated overall (microbial- + macroinvertebrate-driven) decomposition of oak and microbial-driven decomposition of chestnut. The similar shredder densities at elevated and ambient temperatures suggest that stimulated overall decomposition of oak resulted from increased activity of macroinvertebrate individuals. Stimulated microbial-driven decomposition of chestnut resulted from higher fungal activity with warming. Stimulation of litter decomposition by warming can lead to increases in the amount of C returned to the atmosphere and to a faster disappearance of litter from the benthos, with consequences to the C cycle and aquatic food webs.

Future increase in temperature may stimulate litter decomposition in temperate mountain streams: evidence from a stream manipulation experiment

Summary Small woodland streams constitute the majority of water courses in many catchments. Given their generally low water temperature, high surface : volume ratio and primarily heterotrophic nature, such streams can be strongly affected by increases in temperature. It is therefore important to assess how stream communities and processes respond to the global warming projected for this century. We assessed the effects of a c. 3 °C experimental warming of stream water on decomposition of Quercus robur leaf litter and on the associated fungal biomass (ergosterol concentration), sporulation rates of aquatic hyphomycetes, and total macroinvertebrate and shredder abundance in spring, autumn and winter. A mountain stream reach in central Portugal was divided longitudinally over 22 m with local stones. The study followed a before‐after control‐impact design, with both stream halves at ambient temperature during 1 year and one stream half being experimentally warmed in the second year. Experimental warming of stream water stimulated litter decomposition only in winter, probably because at that time, the low natural temperature limited microbial activities. The effect of experimental warming did not depend on the presence of macroinvertebrates. Contrary to expectations, no significant effect of experimental warming was found on fungal biomass accrual, sporulation rate of aquatic hyphomycetes or macroinvertebrate abundance on decomposing litter. Although the stimulation of litter decomposition in winter could lead to food depletion, this is unlikely when streams are subsidised by more recalcitrant leaves such as oak, which enter the stream in later winter and decompose slowly.

Persistence of fecal indicator bacteria in sediment of an oligotrophic river: Comparing large and lab-scale flume systems

In this study, both a lab and a large-scale flume system were used to investigate the survival of fecal indicator bacteria (FIB) in bed sediments of an alpine oligotrophic river. To determine the influence of substratum on persistence, survival within 3-cm-deep substratum cages versus on thin, biofilm-covered ceramic tiles was tested. Moreover, the impact of bed shear stress on survival in bed sediments was explored.It was seen that in the lab-scale flume having a very low bed shear stress (0.3 N m−2), E. coli and enterococci survival in 3-cm-deep substratum cages was nearly the same as in a thin biofilm (200 μm). However, in the large-scale flume system characterized by a bed shear stress of 9 N m−2, the added protection of the deeper substratum cages promoted considerably longer survival of E. coli and enterococci than the thin biofilm. Additionally, the FIB removal mechanisms in the two flume systems varied. At the lab-scale, enterococci was seen to persist twice as long as E. coli, while in the large-scale flume the two FIB were removed at the same rate. A comparison of qPCR analyses performed in both flumes suggests that bed sediment erosion and the influence of grazers/predators were responsible for FIB removal from the sediments in the large-scale flume, whereas in the lab flume FIB inactivation caused removal. These results indicate that hydraulic parameters such as bed shear stress as well as the presence of macroinvertebrates in a system are both important factors to consider when designing flumes as they can significantly impact FIB persistence in sediments of fast-flowing, alpine streams.

The role of stranding and inundation on leaf litter decomposition in headwater streams

Discharge-driven shifts in the wetted area of streams can modify the amount of leaf litter resources available to stream consumers as well as the physical conditions to which leaf litter is exposed. The consequences of this continual movement from wet to dry storage for rates of organic matter processing and resource availability to benthic communities are poorly understood. We used a 30-day field experiment during the period of maximum stream contraction to examine the effects of stranding on black cottonwood ( Populus trichocarpa ) leaf litter decomposition rates and associated changes in microbial respiration in a forested stream in western Montana. Leaf litter was enclosed in both coarse and fine mesh bags and moved from the wetted area of the stream to the stream bank in six treatments designed to mimic a gradient of dry exposure due to stranding. We also measured existing accumulations of organic material in quadrats placed in both wet and dry areas of the stream. The total storage of litter resources (ash-free dry mass, g m 2 ) retained on dry stream banks increased steadily as stream flow decreased, resulting from reductions in wetted width and continuous inputs from terrestrial zones. In contrast, total mass of stored litter submerged in the stream channel remained relatively constant. Leaf decomposition rates increased as a function of time inundated and were fastest in the presence of macroinvertebrates. Our results suggest that prolonged stranding can alter fundamental processes and energy pathways in stream food webs by shifting pools of resources from the active channel to dry storage on riverbanks where decomposition is driven primarily by microbial processes. Since the length of time that leaf litter is inundated prior to stranding alters decomposition rates, changes in stream hydrograph variability (as a consequence of land management practices or incipient climate change) has the potential to alter energy flow through stream systems. In particular, dry storage may function as a type of ‘temporal subsidy’ for stream organisms particularly if slowly decomposing stranded leaf litter is re-entrained during periods when in-stream detrital resources are otherwise scarce.

Invasion risk posed by macroinvertebrates transported in ships’ ballast tanks

Invasions by non-indigenous macroinvertebrates often cause ecological and economic problems, and commercial ships have been implicated as a principal mechanism for their dispersal. We explored the presence and species diversity of adult macroinvertebrates transported by transoceanic and coastal vessels arriving to ports on the Atlantic coast of Canada. We sampled 67 ballast tanks from 62 ships operating along discrete geographic pathways and tested whether mid-ocean exchange or voyage length affects the probability for translocation of macroinvertebrates. Additionally, we assessed the relationship between macroinvertebrate presence and the amount of sediment in ballast tanks. We document the presence of highly invasive European green crab (Carcinus maenas), mud crab (Rhithropanopeus harrisii), common periwinkle (Littorina littorea), soft shell clam (Mya arenaria) and blue mussel (Mytilus galloprovincialis) in ballast tanks of surveyed ships. Mid-ocean exchange did not affect macroinvertebrate occurrence, suggesting that current ballast water management regulations are ineffective for this taxonomic group. Viable individuals were recorded in vessels undertaking shorter voyages (average and maximum of 4.5 and 15 days, respectively) and presence was not related to the amount of sediment in tanks. While presence and densities of macroinvertebrates were low, invasion risk may nonetheless be significant during reproductive seasons owing to high fecundity of some taxa. The highest risk may be posed by decapods since gravid females may carry thousands to several million eggs per clutch, and after several weeks of brooding, two or more subsequent clutches may be fertilized by retained sperm from an earlier mating.

Macro-invertebrates accelerate litter decomposition and nutrient release in a Hawaiian rainforest

Macro-invertebrates (>2 mm in size) can play a key role in litter decomposition by influencing litter chemistry and other components of the decomposer community, thus affecting rates of decomposition, nutrient release, and primary production. However, in many ecosystems the influences of macro-invertebrates on key ecosystem processes have not been adequately addressed. We investigated the influence of the macro-invertebrate community in litter decomposition and the cycling of nutrients in a young rainforest site on the island of Hawaii by using litter bags with and without 2.5 cm holes to allow or prevent access by macro-invertebrates. Presence of macro-invertebrates increased rates of litter decomposition by 16.9% and rates of nutrient release for N and Mn by 33.2% and 30.3%, respectively. Macro-invertebrate activity thus has a major impact on N release accounting for 3.32 kg/ha/yr. This internal ecosystem transfer of N from the litter is greater than estimates of nitrogen inputs from rain water, dry deposition, volcanic sources, atmospheric dust, and nitrogen fixation for this ecosystem. These findings demonstrate that improved knowledge of the ecosystem effects of macro-invertebrates is necessary to understand how ecosystems function.

Application of classification trees and support vector machines to model the presence of macroinvertebrates in rivers in Vietnam

In the present study, classification trees (CTs) and support vector machines (SVMs) were used to study habitat suitability for 30 macroinvertebrate taxa in the Du river in Northern Vietnam. The presence/absence of the 30 most common macroinvertebrate taxa was modelled based on 21 physical-chemical and structural variables. The predictive performance of the CT and SVM models was assessed based on the percentage of Correctly Classified Instances (CCI) and Cohen's kappa statistics. The results of the present study demonstrated that SVMs performed better than CTs. Attribute weighing in SVMs could replace the application of genetic algorithms for input variable selection. By weighing attributes, SVMs provided quantitative correlations between environmental variables and the occurrence of macroinvertebrates and thus allowed better ecological interpretation. SVMs thus proved to have a high potential when applied for decision-making in the context of river restoration and conservation management.

Macrophytes as refuge or risky area for zooplankton: a balance set by littoral predacious macroinvertebrates

Summary1. Zooplankton use macrophytes as day‐time refuge areas when trying to escape from pelagic predators. But macrophytes can also host a diverse and abundant macroinvertebrate assemblage and zooplankton are also likely to face predacious macroinvertebrates once they enter the littoral zone. This study aimed to elucidate the role of macroinvertebrates in determining the refuge capacity of macrophytes.2. We conducted a field enclosure experiment using plastic bags and complementary laboratory feeding trials to test how macroinvertebrates counteract the benefits to zooplankton of the macrophyte refuge. The field experiment consisted of three treatments with different macroinvertebrate assemblages: without predators (WP), low abundance and diversity (LAD) and high abundance and diversity of predators (HAD – which represents lake conditions).3. Populations of Diaphanosoma brachyurum, Bosmina huaronensis and Moina micrura (Cladocera) and of both male and female Notodiaptomus incompositus (Copepoda, Calanoida) declined (by nearly 80%) in the presence of HAD in comparison to WP and LAD treatments.4. Feeding trials revealed that Buenoa sp. (backswimmer), adults of Palaemonetes argentinus (grass shrimp) and Cyanallagma interruptum (damselfly) had a significant negative impact on cladocerans (D. brachyurum, B. huaronensis) and the calanoid copepod population (males, females and copepodites). These predators showed a strong predation effect ranging from 75% to 100% reductions of zooplankton populations.5. The refuge effect offered by macrophytes to zooplankton depends on and is balanced by the predacious macroinvertebrate assemblage that plants host. The risk of confronting littoral predators is high and macroinvertebrate presence can turn the macrophytes into risky areas for zooplankton.

Macroinvertebrate presence in food of fish population from River Buzau (Romania)

(2006). Macroinvertebrate presence in food of fish population from River Buzau (Romania) SIL Proceedings, 1922-2010: Vol. 29, No. 5, pp. 2256-2258.

Irrigation pools as macroinvertebrate habitat in a semi-arid agricultural landscape (SE Spain)

The intensification of agriculture has resulted in the loss of many aquatic ecosystems in southern Europe. Despite this, the construction of irrigation pools and reservoirs to retain the water necessary for intensive cultivation may also provide new habitats for macroinvertebrates. The biotic and abiotic attributes of 40 such reservoirs in south-eastern Spain were studied to determine the presence of macroinvertebrates, and to discover if there is such a thing as an optimal design of an artificial pond for maximizing macroinvertebrate richness. A total of 72 macroinvertebrate taxa belonging to 38 families were recorded from the pools examined. Pools constructed with low-density polyethylene covered with sand and stones contained a significantly greater species richness, abundance and diversity of macroinvertebrates than those constructed with high-density plastic materials. The treatment with algicide, and the presence of emergent and submerged vegetation, accounted for most of the deviance when modelling species richness by means of logistic regression.