Lakes are complex ecosystems composed of distinct habitats coupled by biological, physical and chemical processes. While the ecological and evolutionary characteristics of aquatic organisms reflect habitat coupling in lakes, aquatic ecology has largely studied pelagic, benthic and riparian habitats in isolation from each other. Here, we summarize several ecological and evolutionary patterns that highlight the importance of habitat coupling and discuss their implications for understanding ecosystem processes in lakes. We pay special attention to fishes because they play particularly important roles as habitat couplers as a result of their high mobility and flexible foraging tactics that lead to inter-habitat omnivory. Habitat coupling has important consequences for nutrient cycling, predator-prey interactions, and food web structure and stability. For example, nutrient excretion by benthivorous consumers can account for a substantial fraction of inputs to pelagic nutrient cycles. Benthic resources also subsidize carnivore populations that have important predatory effects on plankton communities. These benthic subsidies stabilize population dynamics of pelagic carnivores and intensify the strength of their interactions with planktonic food webs. Furthermore, anthropogenic disturbances such as eutrophication, habitat modification, and exotic species introductions may severely alter habitat connections and, therefore, the fundamental flows of nutrients and energy in lake ecosystems.
Озера: литофильная фауна литорали.
Volume 39 Issue 3 Page 577-592 - May 1998
The fauna in the upper stony littoral of Danish lakes: macroinvertebrates as trophic indicators
Klaus P. Brodersen, Peter C. Dall AND Claus Lindegaard
1. The macroinvertebrate fauna living on stones in the exposed stony littorals of
thirty-nine Danish lakes were examined by multivariate numerical methods. The data
were derived from 125 semi-quantitative samples and a species list of 126 taxa. The
mean number of individuals per sample was 960, and among the most common taxa
were Asellus aquaticus, Gammarus, Oulimnius, Tinodes, Cricotopus and
2. The total number of species and fourteen individual taxa were positively
correlated to mean depth of the lakes and eleven taxa were correlated to the total
phosphorus concentration. The Shannon diversity was negatively correlated to the
chlorophyll a concentration ([Chla]).
3. Community patterns were examined by detrended correspondence analysis
(DCA), and the relationship between species data and selected environmental
variables was analysed by canonical correspondence analysis (CCA). Mean lake
depth was found to be the strongest environmental variable in explaining the species
data. The [Chla] and Secchi depth also explained significant variation in the
distribution of the stony littoral invertebrates. Wind fetch and relative exposure did
not explain any variation in the faunal composition among sites.
4. The abilities of the macroinvertebrates to predict the lake trophic state, expressed
as log ([Chla]), were explored by means of weighted averaging (WA) regression
and calibration. Two tolerance-weighted WA models using inverse and classical
regression for deshrinking are presented. The models were assessed by the root
mean square error (RMSE) of prediction, using bootstrapping as cross validation,
and by the correlation between observed and inferred log ([Chla]). The model using
inverse deshrinking had a RMSEboot=0.41 and r2=0.63. By using classical
regression, the predictability in the ends of the gradient was improved but the
RMSE increased: RMSEboot=0.46.
5. Although the factors determining faunal distribution patterns in the Danish
lowland lakes were highly multivariate and difficult to disentangle, it seems
reasonable to use the WA estimated species optima and tolerances to [Chla] in a
Бентос в целом.
Volume 47 Issue 3 Page 483 - March 2002
Расселение водных организмов околоводными птицами:
обзор наработок и приоритетные направления дальнейших исследований.
Dispersal of aquatic organisms by waterbirds: a review of past research and
priorities for future studies
JORDI FIGUEROLA & ANDY J. GREEN
1.Inland wetlands constitute ecological islands of aquatic habitat often isolated by
huge areas of non-suitable terrestrial habitats. Although most aquatic organisms lack
the capacity to disperse by themselves to neighbouring catchments, many species
present widespread distributions consistent with frequent dispersal by migratory
2.A literature review indicates that bird-mediated passive transport of propagules of
aquatic invertebrates and plants is a frequent process in the field, at least at a local
scale. Both endozoochory (internal transport) and ectozoochory (external transport)
are important processes.
3.The characteristics of the dispersed and the disperser species that facilitate such
transport remain largely uninvestigated, but a small propagule size tends to favour
dispersal by both internal and external transport.
4.We review the information currently available on the processes of waterbird-
communities varied longitudinally within a drainage basin and from the east to the
west of Victoria. These two trends were superimposed on one another to form a
single gradient on the ordination. The taxon richness of edge communities was also
related to the species richness of macrophytes at a site. Main-channel communities
also displayed a longitudinal and a geographic gradient, but these two gradients
were uncorrelated on the ordination.
5. Community similarity only weakly reflected geographic proximity in either habitat.
A preliminary subdivision of Victoria into a series of biogeographic regions did not
match the pattern of distribution of site groups for the edge habitat, illustrating the
difficulties of applying to lotic communities a priori regionalizations based on
terrestrial features of the landscape.
6. The longitudinal gradients in the two data sets were commonly observed in data
gathered at smaller spatial scales in Victoria. The other gradients (geographic,
macrophyte), however, were either not consistently repeated or not evident at
smaller spatial scales. At small spatial scales (i.e. within a single drainage basin)
gradients were related to variables that varied over restricted ranges, e.g. mean
particle size of the substratum.
7. Species richness was very variable when plotted against river slope or distance of
site from source; both of these are measures of position on the longitudinal
gradients. In contrast to suggestions in the literature, species richness did not show
a unimodal trend on these gradients, or any other trend.
8. Environmental gradients (apart from longitudinal gradients) that underlie
predictive models of macroinvertebrate distribution are reflections of the spatial
scale on which the model has been constructed and cannot be extrapolated to
different scales. Models must be suited to the spatial scale over which predictions
Сообщества бентоса: влияние биот.факторов
Interaction of a Biotic Factor (Predator Presence) and an Abiotic Factor (Low-Oxygen) as an Influence on Benthic Invertebrate Communities
OECOLOGIA 1993, Vol 95, Iss 2, pp 210-219
UNIV-WYOMING, DEPT ZOOL & PHYSIOL, LARAMIE, WY 82071, USA
We examined the response of benthic invertebrates to hypoxia and predation risk in bioassay and behavioral experiments. In the bioassay, four invertebrate species differed widely in their tolerance of hypoxia. The mayfly, Callibaetis montanus, and the beetle larva, Hydaticus modestus, exhibited a low tolerance of hypoxia, the amphipod, Gammarus lacustris, was intermediate in its response and the caddisfly, Hesperophylax occidentalis, showed high tolerance of hypoxia. In the
behavioral experiments, we observed the response of these benthic invertebrates, which differ in locomotor abilities, to vertical oxygen and temperature gradients similar to those in an ice-covered pond. With adequate oxygen, invertebrates typically remained on the bottom substrate. As benthic oxygen declined in the absence of fish, all taxa moved above the benthic refuge to areas with higher oxygen concentrations. In the presence of fish mayflies increased activity whereas all other taxa decreased activity in response to hypoxia. Mayflies and amphipods remained in the benthic refuge longer and endured lower oxygen concentrations whereas the vertical distribution of caddisflies and beetle larvae was not influenced by the presence of fish. As benthic oxygen declined in the presence of fish, all but the beetle larva reduced activity over all oxygen concentrations compared to when fish were absent. As benthic oxygen continued to decline, mayflies and amphipods moved above the benthic refuge and were preyed upon by fish. Thus, highly mobile taxa unable to tolerate hypoxia (mayflies and amphipods) responded behaviorally to declining oxygen concentrations by migrating upward in the water column. Taxa that were less mobile (beetle larvae) or hypoxia-tolerant (caddisflies) showed less of a response. Taxa most vulnerable to fish predation (mayflies and amphipods) showed a stronger behavioral response to predator presence than those less vulnerable (caddisflies and beetle larvae). Because invertebrates differ in their ability to withstand hypoxia, episodes of winter hypoxia could have long-lasting effects on benthic invertebrate communities either by direct mortality or selective predation on less tolerant taxa.