Community structure of phytoplankton,zooplankton and macroinvertebrates inrestored and natural aquatic habitats of Danube Delta – a preliminary assessmentOrhan Ibram – aquatic macroinvertebratesLiliana Török - phytoplanktonMihaela Tudor - zooplankton Hidrobiology Laboratory Danube Delta National Institute
Babina area (satellite images) 1993 1996 1993 1996
-Former polder for forestry Fortuna Lake Danube
Selected natural lakes Cuibul cu Lebede Isac Uzlina Images from GoogleEarth
Chaneging connectivity and lake typology Type 2 Type 1 Type 3 River clay sand-silt organicOOsterberg W., Staras M., Bogdan L., Buijise A. D., Constantinescu A., Coops H., Hanganu J., Ibelings B. W., Menting G. A. M., Navodaru I.and Torok L. (2000) “Ecological gradients in the Danube Delta; present state and man-induced changes”. RIZA the Netherlands, Danube DeltaNational Institute Romania and Danube Delta Biosphere Reserve Authority Romania. RIZA rapport nr. 2000.015
Type 1 lakes•Turbid lakes with high biomassof phytoplankton andzooplankton and a low cover ofaquatic vegetation andfilamentous algae;•The abundance ofcyanobacteria and cladocera isrelatively high;•These lakes tend to be deepand large with sand-silt substrateand a low variation in waterdepth
Type 2 lakes•Clear lakes with a high abundanceof the Potamogeton trichoidescommunity, often with filamentousalgae;•In these lakes phyto- andzooplankton biomass and turbidityare low;•These lakes tend to have a highseasonal variation in waterdepthand a low cumulative residence time
Type 3 lakes•Clear lakes, often withfilamentous alge;•Phyto- and zooplanktonbiomass are low;•Shallow and small withorganic substrate;•High cumulative residencetime
Evolution of phytoplankton diversity in Babina and Fortuna areas •The abundance of the phytoplankton found shows that diatoms constitute a significant component of the community; •The analyis of the saprobic status of the recorded species revealed a predominance of meso-saprobous algae species Analiza comparativă abundenţei numerice vs. diversitate fitoplanctonică în Analiza comparativă a abundenţei numerice relative vs. diversitate fitoplanctonică Ostrovul Babina (2003 & 2010) în incinta Fortuna (2006 & 2010) nr.ind./l H (div.)3000000 4 nr.ind./l H (div.) 1200000 3.5 3.52500000 3 1000000 32000000 2.5 2.5 800000 21500000 2 600000 1.5 1.51000000 400000 1 1 500000 0.5 200000 0.5 0 0 B2 B4 B5 B10 B11A B12 B13 B14 B16 0 0 F - S0 F2 F8 F9 F13 F16 staţii staţii 2003 2010 H/2003 H/2010 2006 2010 H/2006 H/2010
Phytoplankton in natural and restored areas-There is no significant differences betweenphytoplankton development in natural lakescompared with restored areas;-In Isac lake high values of chl “a” are not given byblooms of cyanobacteria which are in generalresponsible for water degradation
Evolution of zooplankton diversity in Babina 200 186 180 160 140 nr.sp. zooplancton 120 100 87 80 71 60 46 34 40 25 19 24 20 9 0 1993 1994 …… 1997 1998 1999 2000 2001 …… 2003 …… 2010•There is a significant increasing of the species number since the polder was flooded(1994), more interesting in the last 4 years when the species number almost getdoubled;• The dominant genus was Brachionus spp, represented by 6 taxa. After flooding thepolder many species that are indicators of permanent waters occurred. The constantforms that occur every year are: Chydoridae (cladocera), Cyclopidae (copepoda) andBrachionidae (rotifera).
Evolution of zooplankton diversity in Babina 16 The frecquency of rotifers families w ithin Babina Island Philodinidae 14 Collothecidae 100% Trichocercidae 12 90% Testudinellidae 80% 10 Synchaetidae nr. ind/l 70% Lecanidae 8 60% Habrotrochidae 50% 6 Dicranophoridae 40% 4 Notommatidae 30% Asplachnidae 2 20% Gastropodidae 10% 0 Lindiidae 0% B10 B16 B2 B14 B12 B11 B5 Adinetidae B13 B4 1997 1998 1999 2000 2001 Brachionidae Cladocera Copepoda Rotifera• The most abundant taxonomic groups recorded until 2010 were the rotiferspecies. The rotifers community across all channels, lake and outlet wasoverwhelmingly dominated by Brachionus spp. (>50%). These species are foundgenerally in eutrophic waters (Berzins and Pejler, 1989).• In terms of density, small herbivorous rotifers (e.g. Keratella sp. andAschomorpha sp.) are the most abundant in the first year after flooding, thesespecies being characteristic for eutrophic waters (Premazzi et al., 1992).
Evolution of zooplankton diversity in Fortuna4,5 0,6 25 nr ind/l 4 0,5 203,5 20 3 0,4 nr.sp.zooplancton 15 15 142,5 0,3 2 101,5 0,2 1 0,1 50,5 m g/l 0 0,0 BR8 BR6 F2 F4 S0 F16 F19 F13 F12 F9 F8 F8A F10 0 2004 2005 2006 ….. 2010 nr ind/l mg/l Zooplankton structure reveals low abunance of Cladocera and dominance of Rotifera group with a low overall abundance; Both species number and no of individuals/liter has decreased
Zooplankton in natural and restored areas Abundance distribution of zooplanckton in natural lakes 35 30 25 no.ind/l 20•Community structure - no difference 15 10between natural and restored areas; 5both types are dominated by 0copepods; Isac Uzlina Cuibul cu Lebede Cladocera Copepoda Rotifera•Differences are related to theabundance; natural lakes with higher Abundance of zooplankton in the "lake" of island Babina andabundances than the restored ones. Fortuna polder 14•There is an “ inside group” difference 12in natural lakes separating Cuibul cu 10 no.ind/l 8Lebede 6 4 2 0 Babina Fortuna Cladocera Copepoda Rotifera
Evolution of aquatic macroinvertebrates diversity in Babina (1996-2010)• The polder waters may basically be classified in two faunistic complexes:1. Running waters-hard bottom-lacking macrophytes;2. Stagnating-permanent or temporary waters; nr. speciiThe hard, loamy substrate next 25to the inlets is densely 20populated by specimens of the 1996snail Lithogliphus naticoides in 1997 15association with Viviparus sp. 1998 1999and Dikerogammarus villosus – 2000 10freshwater shrimp-that hides 2001 2010into the woody litter; 5The second group is composedmainly limnophylous species of 0worms, snails, crustacea, water re e e re e de te re e er er ne ce te te na te po pt pt op di op op ta do ro ro do ru us ih er lemites and aquatic insects. t O te Hi pi as Tr Cr Co em He Le G Ef
Evolution of aquatic macroinvertebrates diversity inBabina (1996-2010) The species composition of the Gastropoda reflects some of the most important characteristics for the functioning of the rehabilitated wetlands of Babina. They live on dead macrophytes and thus contribute to the decomposition of plant biomass being also beneficial to the aerobic conditions in the water; The fluctuation of the specimen number between the channels and lakes is not significant and may be neglected; The species composition in the secondary channels is comparable to that of the main channel
Evolution of aquatic macroinvertebrates diversity in Fortuna (2006 & 2010) 18•Most frequent species 16are Bithynia tentaculata 14and Valvata naticina. 12The first one has broad No of species 10habitat preferences 2006 2010inhabiting both running 8and standing water 6especialy in densely 4vegetated areas. The 2former prefers muddy or 0fine sand sediments and a a ra da a a ta a er er ne er ce te na po pt pt pt di op ta do ro ro ho eo ru us erit is found mainly in on t te O Hi ic l as Co Cr m He Tr G he Epthe shore of thechannels with differentdegree of water velocity
Aquatic macroinvertebrates in natural and restoredareasFive univariate measures are calculated for each spatial category. The number ofspecies (S), total abundance (A), Margalef’s (d) species-richness measure, theShannon-Wiener (H’) diversity index (to base loge), and Pielou’s evennes (J’).The formulae for the indices are as follows:•Margalef’s d = (S-1)/Log (N) – where S is the number of species in the sampleand N is the number of individuals;•Shannon-Wiener H’ = -SUM(Pi x Log (Pi)) – where Pi is the proportion ofspecies found in category I;•Pielou’s evenness J’ = H’/Log (S) – derived from Shannon-Wiener to expressthe observed diversity as a proportion of the maximum possible diversity.
Aquatic macroinvertebrates in natural and restored areasMargalef’s d gives a basic measure of species richness that makes someallowance for the numbers of the individuals present.The magnitude of Shannon-Wiener may be affected by the distribution of thedata, giving underestimates of diversity particularly with small sample sizes,and may also be affected by the number of categories.Pielou’s J’ is used to express homogenity or relative diversity, the moresimilar the proportions of all species in the sample the closer J’ tends towards1
Aquatic macroinvertebrates in natural and restoredareas 25 20 A 1-way ANOVA test of 250 S (no. of species) differences between catchments 15 showed three diversity indices 10 were significantly different. 5 200 (P<0.01) 0 Natural Restored 2.5 0.8 150 0.78 2 individuals 0.76 H (Shannon) 1.5 Pielous (J) 0.74 0.72 1 100 0.7 0.5 0.68 0.66 0 Natural Restored Natural Restored 195 50 4.4 4.3 190 4.2 4.1 Margalefs (d) Abundance (N) 185 4 0 3.9 180 Isac Uzlina Cuibul 3.8 Babina Fortuna 3.7 175 3.6 170 3.5 Natural Restored Natural Restored
Conclusions There is no significant differences between phytoplankton and zooplankton development in natural lakes compared with restored areas regarding community structure as opposed to aquatic macroinvertebrates; Only one year of investigation is not sufficient; extending the analysis to other type of ecosystems like channels because dominate (as a proportion) the restored areas so the lakes are not the best representatives of these areas THANK YOU!
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