Spatiotemporal variation of Diptera changes how we evaluate High Nature Value (HNV) wet grasslands

Proposed strategies to protect biodiversity within agricultural systems are often based on botanical criteria with plant species richness generally considered the prime indicator of conservation potential. While wet grasslands dominated by rushes (Juncus spp.) are commonly considered to be of lesser ecological value than those which are more botanically diverse (e.g. Carex dominated wet grasslands), their value for invertebrates such as Diptera has not yet been fully explored. Data from two Diptera families (Sciomyzidae and Syrphidae) were examined at spatial, temporal and spatiotemporal scales to determine the contribution of two different (Juncus and Carex dominated) wet grassland habitats towards the maintenance of Diptera diversity. The two habitats were significantly different in terms of community structure for both families and temporal variation was a significant component of dipteran diversity. Spatiotemporal analysis showed that species turnover between habitats at different times made the most significant contribution to overall Diptera diversity. Temporal variation of both families suggests that the relative importance of each habitat type to overall diversity fluctuates depending on sampling period, with both habitats supporting diversity at different times. Our results indicate that lowland wet grasslands characterised by Juncus cover need to be recognised as ecologically important for the maintenance of dipteran diversity. We discuss the possible implications for the diversity of Diptera in wet grasslands if these commonly perceived marginal areas (both agriculturally and ecologically) are ignored in conservation strategies. The necessity of recognising spatiotemporal variation when evaluating habitats using invertebrates as indicators is also discussed.     

Grassland invertebrate assemblages in managed landscapes: Effect of host plant and microhabitat architecture

Abstract Grasslands are often considered as two‐dimensional habitats rather than complex, multilayered habitats. However, native grasslands are complex habitats, with multiple layers of annual and perennial grasses, sedges, shrubs and mosses. Vegetation complexity, including plant type, quality and three‐dimensional structure is important for providing a variety of food and habitat resources for insects. Grazing by domestic livestock can affect these processes through the loss or fragmentation of habitats, as well as altering the vertical and horizontal vegetation structure. This study aimed to investigate the role of host plants and microhabitat architecture for determining foliage invertebrate assemblages. Different plant species supported distinct invertebrate assemblages and less complex host plants supported fewer invertebrate individuals and species. Manipulations of plant architecture changed the species composition of invertebrates, with most species found in more complex vegetation. This study illustrates the importance of host diversity and pasture complexity for invertebrate communities. Management practices that encourage a heterogeneous environment with diverse and structurally complex pastures should also sustain a more diverse and functional invertebrate assemblage.     

The Distribution of Grassland Auchenorrhyncha Assemblages (Homoptera: Cercopidae, Cicadellidae, Delphacidae) in Northern England and Scotland

The distribution of Auchenorrhyncha species assemblages on 174 grassland sites in northern England and Scotland was investigated using ordination and classification techniques. Altitude appeared to be the most important environmental variable influencing assemblage distribution but the effects of altitude on soil type and moisture, and on plant composition, either herbaceous or woody, and structure were likely to have been primary influences. The main differences between sites in the eight habitat groups of the classification were products of these soil and plant variables, with the geographical position of sites in the survey area having less of an effect on site classification. A considerable number of nationally and regionally rare and scarce species were recorded. The results indicate that Auchenorrhyncha could be used in site conservation based on invertebrate species assemblages and rare species distribution but that more information is required to assess both habitat diversity and species rarity. More survey work would also be required to identify appropriate site management procedures for the conservation of Auchenorrhyncha within an overall programme for terrestrial invertebrates.     

Effects of vegetation structure and floristic diversity on detritivore,herbivore and predatory invertebrates within calcareous grasslands

Calcareous grasslands in Europe have shown wide scale declines in their extent and quality as a result of modern agricultural practices, increased atmospheric eutrophication and lack of management. In addition to being a key habitat for specialist plants, calcareous grasslands are also important for many threatened invertebrates. In this UK based study, we investigated the impact of military vehicle activity, floral species richness and vegetation structure on assemblages of detritivore, herbivore and predatory invertebrates. We also consider the impact that disturbance by military vehicle activity on the proportion of invertebrate species capable of flight, a surrogate for dispersal ability. Sward height was negatively correlated with detritivore, herbivore and predator species richness. Herbivores species richness was positively correlated with both forb and grass species richness. Spatial variation in the number of plant species was negatively correlated with herbivore species richness. Those sites most heavily disturbed by military vehicle activity supported the lowest proportions of flightless invertebrates. Successful management for calcareous grassland invertebrates should aim to maintain short swards with high floristic diversity, in terms of both the forbs and grasses. It should be noted, however, that these findings refer to principally surface rather than sward active invertebrates. While disturbance associated with military vehicle activity was not found to affect invertebrate species richness, it has negative consequences for the structure of invertebrate assemblages by selecting against invertebrates with low dispersal ability. To support invertebrate diversity in calcareous grasslands we emphasise the need for variety in the timing and type of management applied to promote heterogeneity in sward structure.     

Invertebrate assemblages in relation to habitat types on a floating mat in Mizorogaike Pond, Kyoto, Japan

Abiotic environmental variables and invertebrate assemblages were compared among four habitat types (bare hollow, sphagnum-rich hollow, pool, and mat edge) on a floating mat in Mizorogaike Pond, Kyoto. We found differences in abiotic environments between two hollows and two inundated habitats (pool and mat edge); pH was significantly lower in hollow habitats than in inundated habitats, and water depths were significantly shallower in sphagnum-rich hollows than in inundated sites. The composition of invertebrate assemblages in the hollow was distinct from that in the inundated habitats. The abundances of some dominant invertebrate taxa or functional feeding groups on the floating mat differed between the hollows and inundated habitats, and were correlated with water temperature, pH and depth. These results indicate that habitat heterogeneity created by the coexistence of hollows and inundated habitats contributes to species diversity on the floating mat in Mizorogaike Pond. A comparison of the pH values in different wetlands revealed that both bog- and fen-specific components coexist within this system. In order to adequately manage and conserve peatland ecosystems, it is necessary to consider the importance and vulnerability of both hollows and inundated habitats in peatlands.     

Comparison of butterfly communities and abundances between marginal grasslands and conservation lands in the eastern Great Plains

The alteration and fragmentation of native tallgrass prairie in the Midwestern United States has created a need to identify other land types with the ability to support grassland butterfly species. This study examines butterfly usage of marginal grasslands, which consist of semi-natural grasslands existing within in a larger agricultural matrix, compared to grasslands managed for conservation of prairie species. Using generalized linear mixed models we analyzed how land purpose (marginal vs. conservation grasslands) affected butterfly abundance. We found grassland butterfly species to be significantly more common on conservation grasslands, whereas generalist species were significantly more common on marginal grasslands. Results of ordination analyses indicated that while many species used both types of habitats, butterfly species assemblages were distinct between habitat types and that edge to interior ratio and the floristic quality index of sites were important habitat characteristics driving this distinction. Within conservation grasslands we examined the relationship between butterfly abundance and the planting diversity used in restoring each site. We found higher diversity restorations hosted more individuals of butterflies considered habitat generalists, as well as species considered to be of conservation concern.     

The early effects of afforestation on biodiversity of grasslands in Ireland

The target rate of afforestation in Ireland over the next 30 years is 20,000 ha per year, which would result in an increase of the forest cover from the current 10% to 17%. In order to promote sustainable forest management practices, it is essential to know the composition and conservation value of habitats where afforestation is planned and the effects of subsequent planting upon biodiversity. The objectives of this study were to investigate changes in vegetation composition and diversity of grasslands 5 years after afforestation with Sitka spruce (Picea sitchensis) and determine the primary ecological and management factors responsible for these changes. Species cover, environmental and management data were collected from 16 afforested and unplanted improved and wet grassland site pairs in Ireland. Our results indicate that 5 years after tree planting, there were significant changes in richness, composition, and abundance of species. Competitive and vigorous grasses were more abundant in planted than in unplanted sites, as were generalist species found in both open and wooded habitats, while small-stature shade-sensitive species were less abundant. Vascular plant species richness and Shannon’s diversity index were higher in unplanted wet grassland, than in the planted sites. Bryophyte species richness was higher in planted improved grassland than in unplanted sites. The differences were primarily the result of the exclusion of grazing, ground preparation, changes in nutrient management and drainage for afforestation. Drainage ditches provided a temporary habitat for less competitive species, but the overall effect of drainage was to reduce the diversity of species dependent on wet conditions. Variance partitioning showed differences in the relative influences of environmental and management variables on biodiversity in the two habitats, probably due to the greater pre-afforestation grazing pressure and fertilisation levels in improved grasslands. The differences in biodiversity between planted and unplanted grasslands indicate that afforestation represents a threat to semi-natural habitats where distinctive and highly localised plant communities could potentially occur.     

Insect assemblages in a native (kanuka –

In New Zealand, the European shrub gorse (Ulex europaeus) is becoming the initial post-disturbance shrub, replacing the native myrtaceous manuka (Leptospermum scoparium) and kanuka (Kunzea ericoides) scrub in this role. Change in the dominant vegetation is likely to affect the native invertebrate community. To quantify these changes, we compared the assemblages of four selected insect taxa (Coleoptera, Lepidoptera, and two groups of Diptera, the Tachinidae and the fungus gnats, represented in New Zealand by the families Ditomyiidae, Keroplatidae and Mycetophilidae) in neighboring stands of kanuka and gorse using Malaise and pitfall traps set during December. We sorted 34 387 specimens into 564 recognisable taxonomic units. Ordinations showed that insect assemblages associated with each habitat were distinct for all four insect groups. The gorse habitat was species rich compared with kanuka for tachinids, fungus gnats and Malaise-trapped beetles, and both habitats contained few adventive species. Many species were unique to each habitat. Some species loss might occur if the kanuka-dominated community continues to be replaced by gorse, but gorse is nevertheless considered to be valuable as a habitat for native invertebrates.     

Conservation implications of grazing practices on the plant and dipteran communities of a turlough in Co. Mayo,Ireland

Turloughs, which are classified as priority habitats under the European Habitats Directive, are seasonally flooded depressions found almost exclusively in Ireland. In 2001, three adjacent fields with different stocking densities were selected and plant/dipteran communities within the same vegetation zone of each field (site) were investigated using quadrats and sweep netting, respectively. There was a significant positive relationship between Diptera morphospecies richness/Diptera abundance and mean vegetation height (P < 0.001). However, no significant relationship between Diptera morphospecies richness and plant species richness was found. Median Diptera morphospecies richness per sweep was lower at the site with the highest stocking density (17) than at the other two sites (22 and 31, respectively). Total species richness of Sciomyzidae was greater at the least grazed site (7) than at the more heavily grazed sites (2 and 1, respectively). The results suggest that an evaluation of turlough management practices based on plant communities alone is not sufficient and that at least some areas within the turlough basin remain ungrazed on a rotational basis to ensure maximum diversity of Diptera.     

Declining diversity and abundance of High Arctic fly assemblages over two decades of rapid climate warming

Insects are particularly vulnerable to rapid environmental changes, which are disproportionally affecting high latitudes. Increased temperature could influence insect species differentially and reshape assemblages over time. We quantified temporal assemblage turnover of Arctic Diptera (flies) in the Muscidae, one of the most diverse and abundant families of Arctic insects, using time series data from Zackenberg, north‐east Greenland. We measured temporal patterns of abundance, diversity, and composition of muscid assemblages in wet fen, mesic and arid heath habitats from yearly collections spanning 1996–2014 and tested their relationship to climate. A total of 18 385 individuals representing 16 species of muscid flies were identified. A significant decrease of 80% of total muscid abundance was observed during the study period. Species richness declined in each habitat type but this trend was not significant across habitats. The number of common and abundant species also decreased significantly over time across habitats revealing a temporal modification of species evenness. Significant temporal changes in composition observed in the wet fen and across habitats were mainly driven by a change in relative abundance of certain species rather than by species replacement. Shift in composition in each habitat and decline in muscid abundance across habitats were associated with summer temperature, which has significantly increased over the study period. However, relationships between temperature and muscid abundance at the species level were noticeable for a few species only. Significant directional change in composition was documented in the wet fen but no biotic homogenization across habitats was observed. As one of the few studies of species‐level changes in abundance, diversity and composition of an insect taxon in the Arctic over the past two decades, our study shows that habitat types may modulate insect species responses to recent climate change and that contrasting species responses can alter species assemblages within a few decades.     

Conservation of Grassland Leafhoppers: A Brief Review

The leafhoppers, planthoppers and their allies (collectively known as the Auchenorrhyncha) are presented as a group of insects that are highly appropriate for studying grassland ecology and conservation, evaluating the conservation status of sites and monitoring environmental and habitat change. Semi-natural grasslands typically support dense populations and a wide range of species with diverse ecological strategies. Their numerical dominance in many grasslands means that they have considerable functional significance, both as herbivores and as prey for higher trophic levels. Population and assemblage studies are supported by good ecological knowledge about most species and modern identification keys. Hitherto, most studies have focused on the composition and structure of assemblages and how they are affected by conservation management. However, grasslands support many rare species with small and fragmented populations which deserve conservation attention in their own right, and recent work has started to reflect this. The effects of management on the composition and structure of grassland leafhopper populations and assemblages are described and an assessment is given of the main threats facing individual species and overall diversity. There is a need to synthesise the scattered literature on grassland leafhoppers, to provide a model for how the composition and structure of populations and assemblages respond to major environmental and anthropogenic gradients across large biogeographic areas. Such an analysis could help predict the impact of likely future changes in land use and climate.     

What determines Orthoptera species distribution and richness in temperate semi-natural dry grassland remnants?

Wide-spread fragmentation and isolation of habitats with high nature conservation value lends increasing importance to a better understanding of the factors which determine species richness in isolated habitat patches. Using data of one of the most abundant invertebrate groups in grasslands, Orthoptera, we analysed how species richness and distribution in 60 isolated semi-natural grassland remnants in Austria were affected by five environmental variables (altitude, habitat and land use diversity within each patch, habitat diversity of areas adjacent to each patch, patch size), and related to diversity of their main food source, i.e. vascular plants. We found a significant positive correlation between Orthoptera and vascular plant species richness, with threatened Orthoptera species having the lowest correlation coefficients. Life form diversity of plants was only moderately positively correlated with Orthoptera species richness. Habitat diversity within and adjacent to the grassland patch had by far the highest loadings on the first two axes of the principal component analysis, which jointly explained 99?% of the variance, and proved to be significant for total, threatened and not threatened Orthoptera, as well as for the two Orthoptera orders occurring in Central Europe (Caelifera, Ensifera). Additionally, the distribution of the majority of those 14 Orthoptera species analysed individually was mainly correlated with habitat diversity within and adjacent to the grassland patch. However, the distribution of a significant proportion of species was associated with other factors: five species were closely related to on-site land use diversity and patch size, and the distribution of three Ensifera species was not significantly correlated to any of the explanatory variables. We conclude that a surrogate taxa approach, i.e. the use of well-known taxonomic groups (e.g. vascular plants), may indeed deliver good results for capturing total, but less so for threatened, Orthoptera species richness in semi-natural grassland remnants. Small scale habitat diversity may be crucial to allow for the co-existence of a large number of Orthoptera species and has to be taken equally into account as patch size in nature conservation.     

Spatial Variability in Species Composition in Birds and Insects

If spatial patterns of change within a habitat were similar for both vertebrates and insects, then vertebrates would provide useful surrogates for designing reserves for the conservation of invertebrates. Data from two eucalypt habitats were analysed to determine levels of habitat richness, site richness and species turnover in birds and insects. For birds the relatively low species richness and turnover indicated that sites within the habitat were similar in composition. In wet eucalypt forests Diptera were very speciose with over 1,000 morphospecies sorted. Species turnover was slightly higher than for birds, indicating a large number of species change from site to site. In dry eucalypt woodland, insects trapped through the winter months were not speciose but turnover between sites was very large. This suggests reserves designed to conserve insects may need to be larger than for birds in order to include the high site variability and richness of insect communities.Spatial patterns of birds and insects were investigated further, to determine if sites that were closer together were more similar for both birds and insects. No patterns were found for birds in either habitat suggesting birds are not responding to changes in the environment at this scale. Diptera in wet eucalypt forest showed higher similarity between close sites than distant sites, while for winter insects in dry eucalypt woodland the relationship was significant when two outlier points were removed. Overall, birds are not good surrogates for insects in either habitat as no relationship between birds and insects in site-to-site similarity was found.     

Invertebrate survey of coastal habitats and podocarp forest on Ulva Island,Rakiura National Park,New Zealand

Abstract

Inventory of the invertebrate fauna is important to establish taxonomic diversity, abundance and distribution, and hence the conservation of indigenous biodiversity. Invertebrate assemblages have been documented in some broadleaf‐podocarp forests and grassland habitats in New Zealand, but not in dense stands of coastal forest or in mature podocarp forest. This survey aimed to provide a taxonomic inventory of terrestrial invertebrates and their habitat associations on Ulva Island (Rakiura National Park, Stewart Island), an off‐shore sanctuary of significant conservation value in New Zealand. We systematically documented the invertebrate assemblages collected in ground litter and on tree trunks on the island. The invertebrate specimens identified represented 4 phyla, 6 classes, 25 orders and 62 species. The invertebrate fauna reported in this survey was distinct from those of lowland shrubland and broadleaved‐Nothofagus forests on the mainland, but shared species with that reported from another similar off‐shore island, Codfish Island (Whenua Hou).     

Taxonomic and functional β-diversity of ants along tree plantation chronosequences differ between contrasting biomes

The replacement of natural by anthropogenic habitat changes biological communities in any biome. Variations in environmental conditions along the chronosequence of tree plantations may act as a gradient of environmental filtering where the gain or loss of species occurs. It is expected that environmental filtering increases with the decrease in environmental similarity between the plantations and the natural habitat. Young tree plantations are structurally more similar to grasslands than to mature plantations, which in turn are structurally more similar to subtropical forest than young plantations. This study compares patterns of beta diversity across exotic pine plantation chronosequences in contrasting biomes. We predict that taxonomic and functional beta diversity between plantation and the natural habitat assemblages increase with plantation age in grasslands and decrease in the subtropical forest. We sampled epigean ants and measured environmental variables at 54 plantations of different ages and natural habitats in grassland and forest biomes in Argentina. Taxonomic and functional beta diversity between natural habitat and pine plantations were estimated through dissimilarity indexes of turnover and nestedness. To assess the response of beta diversity estimators to plantation age we performed general linear and non-linear models. Results revealed opposite beta diversity patterns between biomes along the plantation cycle. Turnover increased and nestedness decreased with declining environmental similarity between pine plantations and the natural habitats; changes in the identity of the species were coupled to changes in their functional characteristics. Thus, a given environmental gradient may produce different diversity patterns depending on the regional species pool. Forestry practices that generate environmental conditions similar to natural environments could help to conserve species from the natural habitat.     

Breeding ecology of farmland Yellowhammers Emberiza citrinella

Observations of Yellowhammers flying from nests to foraging sites were used to assess use of foraging habitats in relation to availability. Selection of invertebrates by foraging Yellowhammers was studied using analysis of nestling faecal samples in relation to invertebrate samples taken from farmland habitats. Both data sets were analysed using compositional analysis. Broad-leaved crops and sparsely vegetated areas were favoured early in the breeding season, but cereal crops were increasingly used as these ripened. Unripe cereal grain formed a major component of nestling diet, but invertebrates were fed to all broods. Lepidoptera larvae, Araneae and Tipulidae were consumed more than other invertebrate groups. Nestling mortality was high during cold weather when these invertebrates would have been inactive. We suggest that farming systems that increase habitat diversity and reduce pesticide application to arable crops will benefit Yellowhammers and other farmland buntings.     

The contribution of different habitat types to species diversity of Baltic uplift islands

Islands are vulnerable ecosystems worldwide, increasingly exposed to human pressure, global climate change and invasive species. Thus, understanding island species diversity is key for nature conservation. Recent studies on insular plant communities indicated that habitat-specific species composition and richness might largely affect diversity patterns observed at the island scale. In consequence, habitat-based approaches are needed to (i) estimate how environmental changes at the habitat scale may affect island diversity, and to (ii) estimate the contribution of different patches of the same habitat to island diversity with respect to habitat-specific environmental constraints.In the present study, we tested these habitat-to-island diversity relationships for shoreline habitats (brackish reeds, salt marsh, rocky shore, tall herbs) and island interior habitats (rocks, semi-natural grassland, pioneer forest, coniferous forest, mixed forest) using 108 islands of three Baltic archipelagos in Sweden. These islands differed in terms of island-scale variables describing effects of island configuration and distance, and habitat-scale variables representing the effects of habitat area, abiotic environment and land-use.The studied habitats differed in their contribution to island species diversity, called habitat specificity. Shoreline habitats shared many common specialist species adapted to extreme conditions like sea salt or bird grazing, while habitats of the island interior harbored mainly species adapted to the specific conditions of a single habitat. We found high variability in habitat specificity as a consequence of habitat-specific environmental factors. Variability was highest for grasslands, where it was related to abandonment and soil fertility, stressing the importance of grassland management for maintaining island biodiversity. Habitats with high habitat specificity through either high species richness or many habitat-specific specialists should be the primary targets for biodiversity management.     

Patterns of invertebrate biodiversity across a natural edge

Abstract Most ecologists are comfortable with the notion of habitats as recognizable entities and also with situations where the junction between two adjacent habitats forms a discrete edge. Such edges form naturally because of sharp changes in important edaphic, geomorphological, climatic or chemical properties to which plants, in particular, respond. Less clear is the effect of such edges on assemblages of mobile organisms, especially invertebrates that operate at relatively small spatial scales. The objective of the present study was to sample invertebrate composition across a natural edge between a well‐developed riparian habitat on fluvial sands and a saltbush habitat developed on a stony gibber plain in a semi‐arid region of New South Wales, Australia. A total of 150 pitfall traps on five 1‐km‐long transects that straddled the edge produced more than 13 000 adult specimens from 21 ordinal invertebrate taxa. A total of 10 446 beetle, ant, wasp, fly and springtail specimens were further sorted into 426 morphospecies. Comparisons and estimates of trends in abundance and richness were made, along with computation of multivariate dissimilarity and permutation statistics, to determine if the land system edge was coincident with changes in invertebrate abundance and composition. These analyses were unable to detect disjunctions in diversity coincident with the edge. The data suggest that many taxa are either present consistently in both habitats or are mostly found in one habitat but ‘leak’ several hundred metres across into the other. Few taxa were unique to either habitat. The result is that assemblage composition for invertebrates changes gradually over distances of up to 400 m either side of the edge and that the distance to a recognizable change in composition is taxon dependent. Even sharp habitat edges, as defined by discrete changes in soils and plants, are not edges but broad transition zones for many invertebrate taxa. There are several implications of these results, especially for landscape ecology.     

Concordance among assemblages of upland Amazonian lakes and the structuring role of spatial and environmental factors

Conservation planning and biodiversity monitoring rely exclusively on the use of surrogate groups. However, the effectiveness of these groups in representing unknown biodiversity is rarely tested. These tests can be based on cross-taxon concordance (or congruence) analysis. In a second step, the main mechanisms underlying concordance can be investigated. Here, we evaluated the relative influence of local environmental factors and spatial processes on the patterns of beta-diversity exhibited by phytoplankton, zooplankton and benthic invertebrates and the strength of assemblage concordance among these assemblages in 38 upland Amazonian lakes (northern Brazil) over four years. Zooplankton and benthic invertebrates responded exclusively to environmental variables. These results are in accordance with the expected under the species sorting model, where local factors are the main mechanisms shaping assemblage structure. In general, patterns of concordance between the assemblages were weak and varied through time, indicating that the use of surrogates in freshwater ecosystems may be a flawed approach.     

Resistance to ship-induced waves of benthic invertebrates in various littoral habitats

1. Ship‐induced waves disturb benthic invertebrate assemblages colonizing littoral zones of lakes and rivers. However, the impact of ship‐induced waves on invertebrates has rarely been quantified, and the influencing factors have not been addressed. 2. In an experimental wave tank, five benthic invertebrate species, Bithynia tentaculata, Calopteryx splendens, Dikerogammarus villosus, Gammarus roeseli and Laccophilus hyalinus, were exposed to waves of increasing shear stress (0.43–2.19 N m^?2). Mean number of detached individuals was recorded for five littoral habitats [coarse woody debris (CWD), reeds, sand, stones and tree roots], representing different levels of structural complexity as quantified by their fractal dimensions (FD). 3. Results showed that detachment of invertebrates was significantly related to shear stress in all habitats except tree roots. Detachments averaged for the five species were significantly lower in habitats with a high degree of structural complexity, decreasing in the habitat sequence: sand, CWD, stones, reeds and tree roots. 4. Consistent with their different morphologies and methods of attachment to substrates, the five species displayed differences in their response to hydraulic stress that were dependent on habitat. 5. The increasing sheltering effect of structural habitat complexity was mirrored by increasing dissipation of the kinetic energy of waves; i.e. the FD of the habitat was positively correlated with shear stress reduction due to the flow resistance of the habitat. 6. Network habitats such as tree roots provided the best sheltering conditions against hydraulic disturbance, because they combined good refuge availability for all studied invertebrate species and maximal dissipation of kinetic wave energy. Consequently, persistent anthropogenic impacts, such as lakeshore modification or long‐term exposure to ship‐induced waves, which cause disappearance of complex littoral habitats such as tree roots or dense reed belts, will drastically increase the adverse effects of boating and ship traffic on littoral invertebrate assemblages.