Сукцессия, колонизация и т.п. динамика

Сукцессия, колонизация и т.п. динамика

Динамика биомассы бентоса: влияние факторов

ARCHIV FUR HYDROBIOLOGIE 1995, Vol 132, Iss 4, pp 415-425

Abstract:

Benthic organic matter (BOM) estimated by Ash-Free Dry

Weight (AFDW) was analyzed in three streams of the French

granitic Massif Central mountains. The study sites differed

mainly by riparian and catchment vegetation and by their

morphology. The nature and area of each retentive structure were

determined in each reach.

Unexpectedly we did not observe greater organic matter

accumulation during the leaf fall period or in the most shaded

stream. Most autumnal input of organic material was flushed

during the high discharge period (October to December). The

differences in annual accumulated benthic organic matter (BOM)

between streams and the temporal fluctuation in BOM accumulation

were explained by differences in nature of retention structures

and riparian vegetation. Thus, riparian vegetation played an

important role in the dynamics of stream organic matter, both by

its direct input and as a retention structure. The efficiency of

retention structures (boulders, roots, branches) greatly

depended on water level and discharge.

Расселение разных видов речных беспов

A COMPARATIVE STUDY OF THE DISPERSAL OF 10 SPECIES OF STREAM INVERTEBRATES

Авторы J.M. Elliott

Журнал Freshwater Biology Год выпуска 2003 Дата сентябрь Том 48 Номер 9

Страницы 1652-1668 Статус

1. Apart from downstream dispersal through invertebrate drift, few quantitative data are available to model the dispersal of stream invertebrates, i.e. the outward spreading of animals from their point of origin or release. The present study provides comparative data for 10 species, using two independent methods: unmarked animals in six stream channels built over a stony stream and marked animals in the natural stream. Experiments were performed in April and June 1973 and 1974, with initial numbers of each species varying from 20 to 80 in the stream channels and 20 to 60 for marked animals.

2. Results were the same for marked invertebrates and those in the channels. Dispersal was not density-dependent; the number of dispersing animals was a constant proportion of the initial number for each species. The relationship between upstream or downstream dispersal distance and the number of animals travelling that distance was well described by an inverse power function for all species (exponential and log models were poorer fits). Results varied between species but were similar within species for the 4 months, and therefore were unaffected by variations in mean water velocity (range 0.04-0.35 m s-1 ) or water temperature (range 6.7-8.9 °C in April, 12.1-14.8 °C in June).

3. Species were arranged in order, according to their dispersal abilities. Three carnivores (Perlodes, Rhyacophila, Isoperla ) dispersed most rapidly (70-91% in 24 h, maximum distances 9.5-13.5 m per day), followed by two species (Protonemura, Rhithrogena ) in which about half their initial numbers dispersed (50-51% in 24 h, 7.5-8 m per day), and four species (Ecdyonurus, Hydropsyche, Gammarus, Baetis ) in which less than half dispersed (33-40% in 24 h, 5.5-7 m per day). Dispersal was predominantly upstream for all nine species. Few larvae (20%) of Potamophylax dispersed, with similar maximum upstream and downstream distances of 3.5 m per day. The mean time spent drifting downstream was known for seven species from previous studies, and correlated positively with their dispersal distances. Therefore, the species formed a continuum from rapid to very slow dispersers. These interspecific differences should be considered when evaluating the role of dispersal in the maintenance of genetic diversity in stream invertebrates, and in their ability to colonise or re-colonise habitats.

1. Кроме вниз по течению рассеивания через бесхарактерный дрейф, немного количественных данных доступны, чтобы моделировать рассеивание беспозвоночных потока, то есть распространения направленного наружу животных от их пункта происхождения или выпуска. Существующее исследование обеспечивает сравнительные данные для 10 разновидностей, используя два независимых метода: немаркированные животные в шести каналах потока, построенных по каменному потоку и отмеченным животным в естественном потоке. Эксперименты были выполнены в апреле и июнь 1973 и 1974, с начальными числами каждой разновидности, изменяющейся от 20 до 80 в каналах потока и 20 - 60 для отмеченных животных.

2. Результатами было то же самое для отмеченных беспозвоночных и тех в каналах. Рассеивание не было зависимо плотностью; число рассеивающихся животных было постоянной пропорцией начального числа для каждой разновидности. Отношения между вверх по течению или вниз по течению расстояние рассеивания и число животных, едущий то расстояние было хорошо описано обратной функцией власти для всех разновидностей (показательный, и модели регистрации были более бедны, соответствует). Результаты, различные между разновидностями, но были подобны в пределах разновидностей в течение этих 4 месяцев, и поэтому были незатронуты изменениями в средней водной скорости (диапазон 0.04-0.35 м. s^-1) или водная температура (располагаются 6.7-8.9 °C в апреле, 12.1-14.8 °C в июне).

3. Разновидности были устроены чтобы, согласно их способностям рассеивания. Три плотоядных животных тех (Perlodes, Rhyacophila, Isoperla) рассеянный наиболее быстро (70-91 % в 24 h, максимальные расстояния 9.5-13.5 м. в день), сопровождаемый двумя разновидностями (Protonemura, Rhithrogena), в который приблизительно половина их начальных рассеянных чисел (50-51 % в 24 h, 7.5-8 м. в день), и четыре разновидности (Ecdyonurus, Гидродуша, Gammarus, Baetis), в который меньше чем половина рассеянного (33-40 % в 24 h, 5.5-7 м. в день). Рассеивание было преобладающе вверх по течению для всех девяти разновидностей.

Влияние нарушений бентоса: динамика.

AMERICAN MIDLAND NATURALIST 1996, Vol 135, Iss 1, pp 92-101

Abstract:

Relative importance of different dispersal modes (drift and

crawling) on macroinvertebrate colonization within seasons under

differing disturbance regimes was tested by field experiment.

Forty individual substrata (tiles) were placed in a series of

riffles in Mink Creek, Idaho, a third-order, Rocky Mountain

stream. Twenty tiles were mounted on steel bars to elevate them

above the streambed and 20 were placed directly on the streambed

to distinguish invertebrates colonizing by drift from those

colonizing by crawling. After an initial colonization period of

32 days, all invertebrates were removed from tiles every 2, 4 or

8 days or left undisturbed during the 16 day experimental

period. Experiments were conducted in the spring, summer and

autumn of 1992. In the spring experiment, invertebrate abundance

was greater (524%) but diversity (D) was lower (-42%) on

elevated tiles as compared to unelevated tiles. No significant

differences were found between elevated and unelevated tiles or

disturbance frequencies in terms of abundance and diversity in

summer. Abundance decreased with increasing levels of

disturbance in autumn (-58%) (2-day disturbance to 8-day

disturbance treatments). No significant differences in diversity

were found between disturbance treatments or between tile

elevations in the autumn. Relative importance of drift and

crawling as modes of colonization varied with season.

Colonization through drift was important in spring, when water

temperature was low discharge was high, and algal resources were

low. In summer and autumn, when water temperature was high,

discharge was low, and algal resources were abundant, drifting

and crawling taxa colonized equally rapidly.

Колонизация нового водотока беспами.

Title: Invertebrate Colonization of a New, Man-Made Stream in

Southern Sweden

Source: FRESHWATER BIOLOGY 1991, Vol 26, Iss 2, pp 307-324

UMEA-UNIV, DEPT ANIM ECOL, S-90187 UMEA, SWEDEN

NATL-RIVERS-AUTHOR, UNIV WALES, COLL CARDIFF, DYFED SA15-4EL,

WALES UNIV-LUND, DEPT ANIM ECOL, S-22362 LUND, SWEDEN

Abstract:

1. The invertebrate colonization of a man-made stream,

Flugstrommen, in southern Sweden was monitored for 18 months in

1988 and 1989. Benthic samples were taken on twelve occasions

from three sites (upstream, middle and downstream) and community

structure was compared with that at ten natural, permanent

reference sites nearby.

2. The number of species colonizing increased rapidly

during the first 3 months. The increase was most rapid upstream

but levelled off during the second year at this site, while

numbers continued to increase downstream.

3. Simuliid species were the earliest colonizers and

reached high densities at upstream and middle sites during the

first year. Ephemeropteran and plecopteran species also

occurred early on, whereas Coleoptera, Odonata and Trichoptera

were, on average, slower to colonize. Blackfly densities

decreased upstream after the first year and hydropsychids became

numerically dominant.

4. The colonization order of functional feeding groups was

as predicted: filter feeders first, grazers/collectors

intermediate, predators and shredders last.

5. After a year, the community structure in Flugstrommen

closely resembled that in lake-outlet streams situated in the

area, although communities at the three sites within the stream

were most similar to one another.

6. The possible role of competitive and predatory

processes in determining the observed successional patterns are

discussed.

Колонизация субстрата в водотоках.

Authors: Mckie-B Cranston-PS

Title: Colonization of Experimentally Immersed Wood in South

Eastern Australia - Responses of Feeding Groups to

Changes in Riparian Vegetation

Source: HYDROBIOLOGIA

2001, Vol 452, Iss 1-3, pp 1-14

We investigated macroinvertebrate abundance and functional

feeding groups colonising experimentally-positioned woody

substrates of different species in streams with three different

riparian vegetation types. Native Eucalyptus forest formed a

dense closed canopy over our streams; introduced (exotic, alien)

pine plantation forest did not fully shade the streams, and

grassland streams were completely open, although with woody

riparian vegetation well upstream of our sites.

Macroinvertebrate assemblages varied taxonomically and

functionally with both wood species and riparian vegetation

composition. Two specialist feeding groups responded clearly to

riparian vegetation: wood gougers were most common in forested

streams, and algal grazers in more open streams. Gougers

colonised native Eucalyptus wood in preference to alien species.

Other feeding groups responses showed complex interactions

between vegetation and wood type. Our results indicate the

importance of sampling appropriate substrates when assessing

questions of this type - if seeking shifts in functional

organisation, the substrates on which the feeding groups of

interest occur must be sampled. The composition of the riparian

strip may influence xylophilous communities as much as the

structure (i.e. whether closed or open).

Речной бентос: колонизация.

Matthaei C D. Uehlinger U. Meyer E I. Frutiger A.

Swiss Federal Inst. Environmental Sci. Technol., CH-8600 Duebendorf,

Switzerland.

Recolonization by benthic invertebrates after experimental disturbance in

a Swiss prealpine river // Freshwater Biology 35(2). 1996. 233-248.

1. Although the crucial point of disturbance experiments in streams is the

extent to which they can simulate an actual spate, this aspect has been

widely neglected in the design of such studies. Similarly, the influence

of the specific hydrological disturbance regime of a stream on its benthic

community has received much theoretical attention in recent years, but

hypotheses have rarely been tested in the field. 2. Our field experiment

compared the structure of the benthic invertebrate community in the

prealpine River Necker in north-eastern Switzerland with predictions of

the patch dynamics concept about the faunal composition of frequently

disturbed streams. We also compared the resistance and resilience of the

invertebrates between two sites in the River Necker. A similar substratum

composition at both sites, but higher shear stress values both at baseflow

and bankfull discharge at site 2, implied a higher disturbance frequency

at the latter site. Five patches of stream bed of apprxeq 9 m-2 were

disturbed by kicking and raking at each site, while five similar areas

served as controls. From each plot, six Surber samples were taken: the

first immediately after the disturbance, and the following five 1, 3, 6,

10 and 30 days later. 3. Resilience of the total benthic invertebrate

fauna was high. The total number of individuals recovered to undisturbed

densities within 30 days at site 1 and 6 days at site 2. Taxon richness

recovered within 3 days. In accordance with theory, taxa with high

recolonization rates made up a major percentage of the total number of

individuals, especially in disturbed plots. However, this percentage was

lower at site 2 in spite of the higher disturbance frequency at this site.

Rhithrogena spp., Leuctra spp. and the Simuliidae recovered faster to

undisturbed densities at site 2. In contrast, absolute recolonization

rates of these taxa were higher at site 1, where total invertebrate

densities were more than twice as high as at site 2. 4. Our results

suggest that the time since the last disturbance should be considered as

an important factor in studies of benthic invertebrate communities in

prealpine rivers, because disturbances can alter the community structure.

In frequently disturbed streams, very short sampling intervals may be

needed to detect differences in taxon-specific colonization rates. The

specific hydrological disturbance regime of such streams is also

important, because even within-stream differences in the resilience of the

benthic invertebrate community are possible.

Водотоки: колонизация бентосом субстрата. Аляска.

Freshwater Biology Volume 44 Issue 3 Page 465 - July 2000

Macroinvertebrate community succession in Wolf Point Creek,

Glacier Bay National Park, Alaska

E. A. Flory* and A. M. Milner

1. Macroinvertebrate community development in Wolf Point Creek in Glacier

Bay National Park, Alaska formed by ice recession was investigated from

1991 to 1994 as part of a long-term study of colonization now exceeding 20

years. Chironomidae, the first taxon to colonize the stream, still dominated

the community comprising 75-95% by number, but species succession was

apparent.

2. Species richness in August increased from five species in 1978 to 11 in 1991

and 16 in 1994.

3. Diamesa species, abundant in 1978 at densities exceeding 2 750 m-2, were

not collected in 1994, while Pagastia partica dominated the community with

densities exceeding 10 000 m-2.

4. Sixteen taxa, never previously collected, colonized the stream between 1991

and 1994 including representatives of Coleoptera, Muscidae, Trichoptera,

and the first noninsect taxon, Oligochaeta. Colonization by new taxa was

associated with an increase in summer water temperature and the

development of riparian vegetation.

5. Inter-specific competition is suggested as a possible factor in species

succession and is incorporated into a taxa richness model of community

development in postglacial streams incorporating stable and unstable

channels.

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