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1.
Brucet S Boix D Nathansen LW Quintana XD Jensen E Balayla D Meerhoff M Jeppesen E 《PloS one》2012,7(2):e30877
Climate warming may lead to changes in the trophic structure and diversity of shallow lakes as a combined effect of increased temperature and salinity and likely increased strength of trophic interactions. We investigated the potential effects of temperature, salinity and fish on the plant-associated macroinvertebrate community by introducing artificial plants in eight comparable shallow brackish lakes located in two climatic regions of contrasting temperature: cold-temperate and Mediterranean. In both regions, lakes covered a salinity gradient from freshwater to oligohaline waters. We undertook day and night-time sampling of macroinvertebrates associated with the artificial plants and fish and free-swimming macroinvertebrate predators within artificial plants and in pelagic areas. Our results showed marked differences in the trophic structure between cold and warm shallow lakes. Plant-associated macroinvertebrates and free-swimming macroinvertebrate predators were more abundant and the communities richer in species in the cold compared to the warm climate, most probably as a result of differences in fish predation pressure. Submerged plants in warm brackish lakes did not seem to counteract the effect of fish predation on macroinvertebrates to the same extent as in temperate freshwater lakes, since small fish were abundant and tended to aggregate within the macrophytes. The richness and abundance of most plant-associated macroinvertebrate taxa decreased with salinity. Despite the lower densities of plant-associated macroinvertebrates in the Mediterranean lakes, periphyton biomass was lower than in cold temperate systems, a fact that was mainly attributed to grazing and disturbance by fish. Our results suggest that, if the current process of warming entails higher chances of shallow lakes becoming warmer and more saline, climatic change may result in a decrease in macroinvertebrate species richness and abundance in shallow lakes. 相似文献
2.
Eulittoral macroinvertebrate communities of lowland lakes: discrimination among trophic states 总被引:2,自引:0,他引:2
MARIO BRAUNS XAVIER-FRANÇOIS GARCIA MARTIN T. PUSCH NORBERT WALZ 《Freshwater Biology》2007,52(6):1022-1032
1. Nutrient inputs from urban and agricultural land use often result in shifts in species composition of pelagic and profundal invertebrate communities. Here, we test if nutrient enrichment affects the composition of eulittoral macroinvertebrate communities, and, if so, if macroinvertebrate communities of five different habitat types reflect differences in trophic state. 2. Macroinvertebrate community composition of 36 lakes was significantly correlated with total phosphorus (TP) concentration, the proportion of coarse woody debris (CWD) and root habitats and the proportion of grassland. 3. However, macroinvertebrate communities of five major habitat types from eight lakes were more dissimilar among habitats than among trophic states. Community composition of reed and stone habitats was significantly correlated with wind exposure but not TP concentration, while macroinvertebrate composition of sand habitats was related to TP concentration and coarse sediments. In CWD and root habitats, both TP concentration and a predominance of invasive species covaried, which made it difficult to relate the observed compositional differences to either trophic state or to the effects of competition between native and invasive species. 4. Trophic state influenced the composition of eulittoral macroinvertebrate communities but to a lesser extent than has been previously reported for profundal habitats. Moreover, the effects of trophic state were nested within habitat type and were partially superseded by biotic interactions and small‐scaled habitat complexity. Although eulittoral macroinvertebrate communities were not strong indicators of the trophic state of lowland lakes, they may be used to assess other anthropogenic impacts on lakeshores. 相似文献
3.
4.
Spatial changes in structural and functional characteristics of fish and macroinvertebrate communities in eastern Kentucky
were investigated in a drainage system chronically exposed to high levels of chloride salts from nearby oilfield operations.
Salinity levels at biological monitoring stations ranged from 0.12–31.3‰. Lotic regions with salinities greater than 10‰ were
dominated by larvae of the dipterans Ephydra and Culicoides. In regions with salinities less than 10‰ species richness increased more or less linearly with decreasing levels of chloride
salts. Ephemeropterans appeared to be one of the major invertebrate groups least tolerant of elevated NaCl levels and were
absent in regions with salinities greater than 2‰ Availability of food resources, such as periphyton and particulate organic
matter, did not appear to be grossly altered in disturbed regions, and it is suggested that the observed distribution of macroinvertebrate
fauna was largely in response to taxonomic differences in salt tolerance. Fish seemed to be more tolerant of highly saline
conditions, and several species were observed in regions experiencing salinities as high as 15‰. Accordingly, assemblages
of fish taxa along the salinity gradient may have been influenced by trophic factors, such as spatial limitations in availability
of invertebrate prey. 相似文献
5.
A detailed survey was undertaken of the microbial communities of 16 saline lakes in the Vestfold Hills (Princess Elizabeth
Land, eastern Antarctica), which ranged in salinity from slightly brackish (4–5‰) to hypersaline (maximum: 174‰). Temperatures
at comparable sampling depths in the lakes ranged from −12.2°C to +10.5°C. Ranges in the abundances of bacteria, heterotrophic
nanoflagellates (HNAN) and phototrophic nanoflagellates (PNAN) were 1.40 × 107 l−1–1.58 × 1010 l−1, 4.83 × 104 l−1–1.70 × 107 l−1 and 0–1.02 × 107 l−1, respectively. There was considerable variation across the salinity spectrum, though in the case of bacteria and PNAN significantly
higher concentrations of cells were seen in two of the most saline lakes. The autotrophic ciliate Mesodinium rubrum occurred in all but five of the lakes and was found at salinity levels up to 108‰. Heterotrophic ciliates were generally
scarce. Dinoflagellates, particularly Gonyaulax c.f. tamarensis, Gyrodinium lachryma and Gymnodinium sp., occurred in the majority of the lakes. On the basis of chlorophyll a concentrations, nutrient levels and microplankton concentrations the lakes spanned the spectrum from ultra-oligotrophic to
oligo/mesotrophic. The most saline lakes had much reduced species diversity compared with the less saline environments. Isolation
from the marine environment has led to nutrient depletion, simplification and a truncated trophic structure.
Received: 19 September 1996 / Accepted: 13 January 1997 相似文献
6.
Chinese and Mongolian saline lakes: a limnological overview 总被引:8,自引:2,他引:6
W. D. Williams 《Hydrobiologia》1991,210(1-2):39-66
More than half of China's lakes are saline (viz. have salinities > 3 g L−1). Most salt lakes are in northwestern China (Tibet, Qinghai, Sinkiang, Inner Mongolia). Most Mongolian salt lakes are in
the west of that country. Tectonic movements have been of the greatest importance in lake origins, but aeolian activity and
deflation have also played a role. Many salt lakes in Qinghai-Tibet lie at altitudes > 4 000 m.a.s.l.; Aiding Hu (Sinkiang)
lies at −154 m.a.s.l. Again, many lakes are large in area and deep. Small, shallow lakes are also common. Dimictic thermal
patterns prevail in deep lakes, polymictic patterns in shallow ones. The highest salinity recorded is 555 g L−1. The salinity of Qinghai Lake, the largest Chinese salt lake, is 14 g L−1, but mean lake salinity on the northern Tibetan plateau is about an order of magnitude greater. Lop Nor has a salinity of
∼ 5 g L−1. Dominant ions are Na and Cl; Mg, Ca, SO4 and HCO3 + CO3 are important in certain lakes. Most major ions originate by weathering and leaching from rocks. pH values are generally
high (often > 9.0).
There are no bird or fish species confined to salt lakes, though many are associated with lakes of low or moderate salinity.
Artemia occurs widely inland and in coastal salt pans, but is the only major macroinvertebrate of highly saline lakes. In lakes of
only low to moderate salinity, invertebrate communities comprise widespread halotolerant freshwater forms and halophiles,
some regionally endemic. Submerged and emergent macrophytes occur in lakes of low salinity, but phytoplankton species are
more halotolerant. Ctenocladus circinatus, a green alga, is known from a Tibetan salt lake with a salinity of 200 g L−1.
There is a dearth of basic limnological information on Chinese and Mongolian salt lakes. More work in particular is needed
on a variety of geographically widespread lakes to (a) document seasonal physico-chemical events, and (b) compile comprehensive
biological inventories of taxa present. Chinese salt lakes are significant sites for palaeoclimatic research, for conservation
purposes, and for the resolution of several important biological questions (especially of an ecological and biogeographical
sort). They also have important economic values. Unfortunately, the natural existence of many appears to be threatened by
decreased inflows, largely the result of human impact on catchments. 相似文献
7.
V. V. Takhteev A. V. Galimzyanova E. V. Ambrosova L. S. Kravtsova N. A. Rozhkova G. L. Okuneva V. P. Semernoi G. I. Pomazkova O. G. Lopatovskaya 《Biology Bulletin》2010,37(6):638-646
The faunal composition, structure of the zoobenthos communities, and seasonal changes in two springs in the south of Irkutsk
area are investigated. Both springs have the water temperature 4–5°C all year round. The fauna consists of widely distributed
hydrobionts, crenobionts, stygobionts, and near-water organisms. Arctic relicts and elements of the Lake Baikal fauna are
found. In macroinvertebrate communities, chironomid larvae dominate (by abundance and biomass), as do oligochaetes (by abundance).
The lowest quantitative parameters are recorded in autumn-winter, and the highest parameters, in spring (March–April). Then
they abruptly decline owing to emergence of amphibiotic insects. The structure of spring communities has regional specificity.
By biomass of macrozoobenthos, the springs are comparable with mesotrophic and even eutrophic lakes. 相似文献
8.
Differential sensitivity of planktonic trophic levels to extreme summer temperatures in boreal lakes
The stress–size hypothesis predicts that smaller organisms will be less sensitive to stress. Consequently, climate warming
is expected to favour smaller taxa from lower trophic levels and smaller individuals within populations. To test these hypotheses,
we surveyed zooplankton communities in 20 boreal lakes in Killarney Provincial Park, Canada during 2005 (an anomalously warm
summer) and 2006 (a normal summer). Higher trophic levels had larger responses to warm temperatures supporting the stress–size
hypothesis; however, rather than imposing negative effects, higher density and biomass were observed under warmer temperatures.
As a result, larger taxa from higher trophic levels were disproportionately favoured with warming, precluding an expected
shift towards smaller species. Proportionately greater increases in metabolic rates of larger organisms or altered biotic
interactions (e.g. predation and competition) are possible explanations for shifts in biomass distribution. Warmer temperatures
also favoured smaller individuals of the two most common species, in agreement with the stress–size hypothesis. Despite this,
these populations had higher biomass in the warm summer. Therefore, reduced adult survivorship may have triggered these species
to invest in reproduction over growth. Hence, warmer epilimnions, higher zooplankton biomass and smaller individuals within
zooplankton populations may function as sensitive indicators of climate warming in boreal lakes. 相似文献
9.
In dimictic, temperate lakes little is known about the quantitative importance of trophic coupling between pelagic and profundal communities. Although it is a generally accepted paradigm that profundal secondary production is dependent on autochthonous pelagic production (primarily diatoms), the importance of interactions between phytodetrital inputs, sediment bacteria, and macroinvertebrates are still not well understood. In this study, we used theoretical models to estimate macroinvertebrate carbon requirement (production + respiration) and bacterial production for lakes of different trophic categories. Comparisons of estimates show that the importance of bacterial production as a carbon source for benthic macroinvertebrates is inversely related to lake trophic state. Assuming that infauna assimilates 50% of ingested bacterial carbon, this food source could account for between 47% (oligotrophic lakes) and 2% (hypertrophic lakes) of their carbon demand. These calculations indicate that bacterial carbon should not be an important C-resource for profundal macroinvertebrates of eutrophic and hypertrophic lakes. 相似文献
10.
We investigated the predatory effects of Dytiscus alaskanus, a large predaceous diving beetle, on the biomass, species composition and diversity of fishless pond communities. The effects
were tested using presence and absence treatments of D. alaskanus in 24 mesocosms distributed among six ponds. We sampled phytoplankton, zooplankton and macroinvertebrates every two weeks
for a six week period. Periphyton was sampled from the mesocosm walls on the final day. Total macroinvertebrate biomass decreased
in the presence of dytiscids while species richness was not affected. Macroinvertebrate predators, snails and Gammarus lacustris decreased in the dytiscid treatments. Laboratory feeding experiments confirmed feeding preferences consistent with the mesocosm
results. Periphyton biomass was six times greater in the dytiscid enclosures, concomitant with the decreased grazing by gastropods
and other invertebrate primary consumers indicating a benthic trophic cascade. Top–down effects of dytiscids on other predatory
invertebrates led to increased total zooplankton biomass, largely due to increased abundances of large and small cladocerans.
Zooplankton species richness increased in the dytiscid enclosures. Inconsistent with trophic cascade theory, phytoplankton
did not respond to top–down effects of D. alaskanus within the study period. Overall, the results show D. alaskanus predation caused trophic effects via two distinct food chains, a dytiscid–snail–periphyton trophic cascade, and a dytiscid–predatory
macroinvertebrates–zooplankton partial trophic cascade. 相似文献
11.
Among-habitat and Temporal Variability of Selected Macroinvertebrate Based Metrics in a Mediterranean Shallow Lake (NW Spain) 总被引:1,自引:0,他引:1
According to the European Water Framework Directive, waterbodies have to be classified on the basis of their ecological status
using biological quality elements, such as macroinvertebrates. This needs to take into consideration the influence of natural
variation (both spatial and temporal) of reference biological communities as this may obscure the effects caused by anthropogenic
disturbance. We studied the influence of among-habitat and temporal (seasonal and interannual) changes on the macroinvertebrate
communities of an Iberian shallow lake and the variability of 21 measures potentially useful for bioindication purposes. Two
series of data were examined: (a) macroinvertebrate samples taken on four occasions over an annual cycle were used to assess
the effects of seasonality and among-habitat variability; (b) macroinvertebrate samples collected in three consecutive summers
were used to assess interannual variability. Coefficients of variation, expressed as percentage, were used to quantify the
effect of among-habitat and temporal variability on the selected metrics. According to our results, % Insecta, Shannon–Wiener
diversity index and the qualitative taxonomic metrics (measures based on number of taxa) were robust in terms of temporal
(seasonal and interannual) and among-habitat variability. Abundance ratio and some metrics based on functional feeding groups
were highly variable. Therefore, qualitative taxonomic metrics may be promising tools in biomonitoring programs of Mediterranean
shallow lakes due to their comparatively low variability. 相似文献
12.
Elisabeth Jensen Sandra Brucet Mariana Meerhoff Louise Nathansen Erik Jeppesen 《Hydrobiologia》2010,646(1):215-229
Diel horizontal migration (DHM), where zooplankton moves towards macrophytes during daytime to avoid planktivorous fish, has
been reported as a common migration pattern of zooplankton in shallow temperate freshwater lakes. However, in shallow eutrophic
brackish lakes, macrophytes seem not to have the same refuge effect, as these lakes may remain turbid even at relatively high
macrophyte abundances. To investigate the extent to which macrophytes serve as a refuge for zooplankton at different salinities,
we introduced artificial plants mimicking submerged macrophytes in the littoral zone of four shallow lakes, with salinities
ranging from almost freshwater (0.3) to oligohaline waters (3.8). Furthermore, we examined the effects of different salinities
on the community structure. Diel samples of zooplankton were taken from artificial plants, from areas where macrophytes had
been removed (intermediate areas) and, in two of the lakes, also in open water. Fish and macroinvertebrates were sampled amongst
the artificial plants and in intermediate areas to investigate their influence on zooplankton migration. Our results indicated
that diel vertical migration (DVM) was the most frequent migration pattern of zooplankton groups, suggesting that submerged
macrophytes were a poor refuge against predation at all salinities under study. Presumably, this pattern was the result of
the relatively high densities of small planktivorous fish and macroinvertebrate predators within the submerged plants. In
addition, we found major differences in the composition of zooplankton, fish and macroinvertebrate communities at the different
salinities and species richness and diversity of zooplankton decreased with increasing salinity. At low salinities both planktonic/free-swimming
and benthic/plant-associated cladocerans occurred, whilst only benthic ones occurred at the highest salinity. The low zooplankton
biomass and overall smaller-bodied zooplankton specimens may result in a lower grazing capacity on phytoplankton, and enhance
the turbid state in nutrient rich shallow brackish lakes. 相似文献
13.
Invasive carp and prey community composition disrupt trophic cascades in eutrophic ponds 总被引:1,自引:0,他引:1
The role of trophic cascades in structuring freshwater communities has been extensively studied. Most of this work, however,
has been conducted in oligotrophic northern lakes that contain highly vulnerable cyprinid prey: aquatic communities where
trophic interactions are likely to be stronger than in many other systems. Fewer studies have been conducted in eutrophic
systems or have examined the bottom-up effects of benthivorous fishes, and none have directly compared these effects to those
of piscivores on ecosystem structure and function. We conducted enclosure experiments in eutrophic ponds to examine trophic
effects of invasive benthivores (common carp—Cyprinus carpio L.), native piscivores (largemouth bass—Micropterus salmoides [Lacepède]), and their interactions with common centrarchid prey with well-developed anti-predatory behaviors (age-1 bluegill—Lepomis macrochirus Rafinesque and young-of-year largemouth bass). At the end of the 60-day experiment, common carp had strong bottom-up effects
that increased total phosphorus and turbidity while decreasing chlorophyll a biomass and macrophyte cover that resulted in decreased macroinvertebrate biomass and also decreased growth in both juvenile
largemouth bass and bluegill. Piscivorous largemouth bass, however, did not affect the survival of either planktivorous juvenile
largemouth bass or bluegill. Growth of juvenile largemouth bass was also not affected, but juvenile bluegill growth was significantly
diminished, possibly due to nonconsumptive effects of predation. Our results suggest that, in a centrarchid-dominated eutrophic
system, top-down effects of predators are overwhelmed by common carp-mediated bottom-up effects. These bottom-up effects strongly
affected multiple trophic levels, thus altering aquatic community structure and function. 相似文献
14.
Hugo Sarmento 《Hydrobiologia》2012,684(1):1-14
Biological invasions of aquatic plants (i.e., macrophytes) are a worldwide phenomenon, and within the last 15 years researchers
have started to focus on the influence of these species on aquatic communities and ecosystem dynamics. We reviewed current
literature to identify how invasive macrophyte species impact fishes and macroinvertebrates, explore how these mechanisms
deviate (or not) from the accepted model of plant–fish interactions, and assess how traits that enable macrophytes to invade
are linked to effects on fish and macroinvertebrate communities. We found that in certain instances, invasive macrophytes
increased habitat complexity, hypoxia, allelopathic chemicals, facilitation of other exotic species, and inferior food quality
leading to a decrease in abundance of native fish and macroinvertebrate species. However, mechanisms underlying invasive macrophyte
impacts on fish and macroinvertebrate communities (i.e., biomass production, photosynthesis, decomposition, and substrate
stabilization) were not fundamentally different than those of native macrophytes. We identified three invasive traits largely
responsible for negative effects on fish and macroinvertebrate communities: increased growth rate, allelopathic chemical production,
and phenotypic plasticity allowing for greater adaptation to environmental conditions than native species. We suggest that
information on invasive macrophytes (including invasive traits) along with environmental data could be used to create models
to better predict impacts of macrophyte invasion. However, effects of invasive macrophytes on trophic dynamics are less well-known
and more research is essential to define system level processes. 相似文献
15.
Salinity effects on macroinvertebrate assemblages and waterbird food webs in shallow lakes of the Wyoming High Plains 总被引:5,自引:5,他引:0
We determined the biomass and community structure of macroinvertebrates (>500 µm) associated with macrophytes, sediments, and unvegetated open water in three oligosaline (0.8 to 8.0 mS cm–1) and three mesosaline (8.0 to 30.0 mS cm–1) lakes in the Wyoming High Plains, USA. Total biomass of epiphytic and benthic invertebrates did not change with salinity, but biomass of macroinvertebrate zooplankton in open water was significantly higher in mesosaline lakes. Community composition of invertebrates differed between the two salinity categories: large grazer/detritivores (gastropods and amphipods) were dominant in oligosaline lakes, whereas small planktivores and their insect predators were more prevalent in mesosaline lakes. Both direct physiological effects of salinity, as well as a shift in the form of primary production from macrophytes to phytoplankton, probably explain these changes in community composition. Salinity effects on invertebrate communities appear to be less important to top avian consumers than are costs of osmoregulation. 相似文献
16.
A survey of 11 sites covering three large (>10 km long, 6 sites) playa lakes and four pans (<1 km2, 5 sites) of the Yarra Yarra salt lake system in the Northern Agricultural Region of Western Australia commenced in 2001.
These salt lakes are shallow and ephemeral, with inundation being more regular following winter rainfall, but summer inundation
also occurred in 2001. Salinity was generally higher in playas (156–368 g l−1) than pans (30–284 g l−1), but salinity responded noticeably to heavy rainfall events, especially in pans. pH values in the playa lakes (6.68–7.82)
were less variable than in the pans (6.81–8.08). The range of dissolved oxygen concentrations was greater in pans (3.7–14.4
mg l−1) than in playas (3.9–8.2 mg l−1). Cationic concentrations generally followed the pattern of sea water cation dominance. Benthic microbial communities comprised
either cohesive to loosely mucilaginous mats, or thin films of diatoms. Five genera of diatom and two species of filamentous
cyanobacteria were recorded.
Guest Editor: John M. Melack
Saline Waters and their Biota 相似文献
17.
Zuzana Čiamporová-Zaťovičová Ladislav Hamerlík Ferdinand Šporka Peter Bitušík 《Hydrobiologia》2010,648(1):19-34
Littoral benthic macroinvertebrates were studied in three alpine lakes in the High Tatra Mountains (Slovakia) located at different
elevations: 2157, 1940 (alpine zone) and 1725 m (sub-alpine zone). The study sites were selected in order to obtain a gradient
in thermal regimes and particular organic matter (POM). Differences in the faunal composition of lakes were tested for the
ability of these differences to indicate climatic changes, and species/taxa were identified that could be used for the purposes
of monitoring and climate change assessment. Macroinvertebrates were sampled quantitatively during the ice-free seasons of
2000 and 2001, and lake surface water temperature (LSWT) and POM were measured. LSWT and POM were negatively correlated with
elevation, whereas ice cover was positively correlated with elevation. A total of 60 oligostenothermic macroinvertebrate species/taxa
were collected belonging to ten higher taxonomic groups. Statistical analysis showed trends in several biotic metrics with
altitude. More specifically, there was a clear increase in the number of species/taxa, genera, and higher taxonomic groups,
as well as an increase in the Shannon–Wiener diversity with decreasing altitude. On the contrary, evenness and density of
benthic macroinvertebrates did not show any clear relationship with altitude. Gatherers of detrital particles dominated the
assemblages’ trophic structures, but no distinct changes in the proportion of functional feeding groups along the altitudinal
gradient were found. While the non-insect fauna of the lakes was rather uniform across the elevational gradient, the insect
fauna composition was highly correlated with altitude, as confirmed by Detrended Correspondence Analysis. Aquatic insects,
in particular chironomids and caddisflies, can therefore be used as good indicators of temperature changes. Our results suggest
that under warmer conditions, non-insect benthic macroinvertebrates will remain more or less stable, while aquatic insects
will undergo an increase in the number of thermophilic species typical for lower altitudes. These colonizers will increase
the diversity of alpine lakes, while the extinction of cold stenothermal species will lead to impoverishment of the native
fauna. An indirect impact on benthic macroinvertebrates through changes in food sources is likely, and changes in trophic
structure of the littoral assemblages can be expected. 相似文献
18.
Benthic macroinvertebrates associated with four species of macrophytes (Nymphoides peltata, Ceratophyllum demersum, Polygonum amphibium and Carex sp.) were investigated during two growing seasons (2001 and 2002) in the slow-flowing Čonakut Channel in the Kopački rit
Nature Park in Croatia. A total of 31 macroinvertebrate taxa were found. C. demersum, a submerged plant with dissected leaves, supported the highest macroinvertebrate abundance, almost seven times more than
N. peltata, a floating plant with undissected leaves, which harboured the lowest abundance during the research period. Chironomidae
larvae (50–83%) and Oligochaeta (14–46%) were the most abundant groups recorded on all macrophyte species. Water-level fluctuation,
because of its influence on the appearance and growth of aquatic vegetation, and the trophic state of water within the macrophyte
stands seemed to be the main factors which affected the taxonomic composition and abundance of macroinvertebrates. 相似文献
19.
1. Little is known about native communities in naturally fishless lakes in eastern North America, a region where fish stocking has led to a decline in these habitats. 2. Our study objectives were to: (i) characterise and compare macroinvertebrate communities in fishless lakes found in two biophysical regions of Maine (U.S.A.): kettle lakes in the eastern lowlands and foothills and headwater lakes in the central and western mountains; (ii) identify unique attributes of fishless lake macroinvertebrate communities compared to lakes with fish and (iii) develop a method to efficiently identify fishless lakes when thorough fish surveys are not possible. 3. We quantified macroinvertebrate community structure in the two physiographic fishless lake types (n = 8 kettle lakes; n = 8 headwater lakes) with submerged light traps and sweep nets. We also compared fishless lake macroinvertebrate communities to those in fish‐containing lakes (n = 18) of similar size, location and maximum depth. We used non‐metric multidimensional scaling to assess differences in community structure and t‐tests for taxon‐specific comparisons between lakes. 4. Few differences in macroinvertebrate communities between the two physiographic fishless lake types were apparent. Fishless and fish‐containing lakes had numerous differences in macroinvertebrate community structure, abundance, taxonomic composition and species richness. Fish presence or absence was a stronger determinant of community structure in our study than differences in physical conditions relating to lake origin and physiography. 5. Communities in fishless lakes were more speciose and abundant than in fish‐containing lakes, especially taxa that are large, active and free‐swimming. Families differing in abundance and taxonomic composition included Notonectidae, Corixidae, Gyrinidae, Dytiscidae, Aeshnidae, Libellulidae and Chaoboridae. 6. We identified six taxa unique to fishless lakes that are robust indicators of fish absence: Graphoderus liberus, Hesperocorixa spp., Dineutus spp., Chaoborus americanus, Notonecta insulata and Callicorixa spp. These taxa are collected most effectively with submerged light traps. 7. Naturally fishless lakes warrant conservation, because they provide habitat for a unique suite of organisms that thrive in the absence of fish predation. 相似文献
20.
Loss of diversity and degradation of wetlands as a result of introducing exotic crayfish 总被引:4,自引:0,他引:4
C.F. Rodríguez E. Bécares M. Fernández-aláez C. Fernández-aláez 《Biological invasions》2005,7(1):75-85
The introduction of the alocthonous Louisiana red swamp crayfish (Procambarus clarkii) in Chozas (a small shallow lake situated in León (North-West Spain)) in 1996 switched the clear water conditions that harboured
an abundant and a quite high richness of plants, invertebrates, amphibians and birds to a turbid one followed by strong losses
in abundance and richness in the aforementioned groups. Crayfish exclusion experiments done in Chozas previous to this work
confirmed the role of crayfish herbivorism on macrophyte destruction that had a trophic cascade effect on the wetland ecosystem.
Direct and indirect effects of crayfish introduction on Chozas lake communities have been evaluated and compared with previous
conditions before 1996 or with other related lakes in which crayfish were no present. Crayfish had a main role in submerged
plant destruction and a potential effect on amphibia and macroinvertebrate population decrease. Plant destruction (99 % plant
coverage reduction) was directly related to invertebrates (71 % losses in macroinvertebrate genera), amphibia (83 % reductions
in species), and waterfowls (52 % reduction). Plant-eating birds were negatively affected (75 % losses in ducks species);
nevertheless, fish and crayfish eating birds increased their presence since the introduction. Introduction of crayfish in
shallow plant-dominated lakes in Spain is a main risk for richness maintenance in these endangered ecosystems.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献