Stream communities & ecosystems. Limnology Lecture 22

Transcription

1 Stream communities & ecosystems Limnology Lecture 22

2 Resource partitioning Coexistence through resource partitioning 3 Major Axes Typically Evaluated 1. Habitat 2. Diet 3. Time (season or time of day) Schoener, T.W. 1974

3 Habitat Partioning Notropis longirostris Notropis welaka

4 Diet Partitioning Serrasalmus rhombeus Hoplias malabaricus

5 Temporal Partitioning Ephemerella subvaria White Clay Creek, PA

6 Intermediate disturbance hypothesis in rivers Townsend & Scarsbrook 1997 Partition habitat by disturbance-biotic interaction tradeoff

7 Colonization-competition tradeoff Some evidence for tradeoff between two traits Colonization ability Competition ability

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9 Succession in rivers Succession predictable changes in community following disturbance or creation of new habitat What do you expect to happen in streams?

10 Rapid recovery after disturbance

11 Rapid recovery after disturbance Small ephemeroptera, chironomids, beetles, simulidae flies colonize rapidly

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14 Wolf Point Creek

15 Long-term assembly at Wolf Point Creek First non-flying invert.

16 Wolf Point Creek Major groups still colonizing after 30 years

17 Food Webs Broadstone stream One of best understood streams in world Woodward et al AER

18 Food Webs Food web interactions change through time Many weak interactions at any given point

19 Food Webs Power 1990

20 With fish Food Webs Chironomids Pred. insects Fish fry

21 Food Webs With fish Odd food chain Even food chain

22 Diversity patterns in streams EPT index Ephemeroptera Plecoptera Trichoptera why these taxa? Easily ID d Tend to be sensitive to human disturbance

23 Diversity patterns in streams Tolerance ability to withstand (human) disturbance Usually based on finding them in healthy habitats What is healthy? Should be based on ecotoxicology

24 Comparing stream & lake communities Small rivers Large rivers Ponds Lakes Macrophyte habitat Sediment stability Sediment loading

25 Comparing stream & lake communities Small rivers Large rivers Ponds Lakes Macrophyte habitat Sediment stability Sediment loading Low Moderate High Moderate

26 Comparing stream & lake communities Small rivers Large rivers Ponds Lakes Macrophyte habitat Sediment stability Sediment loading Low Moderate High Moderate Low, catastrophic flooding Low, shifting sands High High

27 Comparing stream & lake communities Small rivers Large rivers Ponds Lakes Macrophyte habitat Sediment stability Sediment loading Low Moderate High Moderate Low, catastrophic flooding Low, shifting sands High High Low High Moderate Low

28 Comparing stream & lake communities Small rivers Large rivers Ponds Lakes Benthic richness Important guilds Dominant food sources

29 Comparing stream & lake communities Small rivers Large rivers Ponds Lakes Benthic richness Important guilds Dominant food sources Low High High Low

30 Comparing stream & lake communities Small rivers Large rivers Ponds Lakes Benthic richness Important guilds Dominant food sources Low High High Low Shredders, collectors Grazers, collectors Grazers, collectors, shredders Grazers, collectors, shredders

31 Comparing stream & lake communities Small rivers Large rivers Ponds Lakes Benthic richness Important guilds Dominant food sources Low High High Low Shredders, collectors CPOM, periphyton Grazers, collectors FPOM Grazers, collectors, shredders CPOM, periphyton, phytoplankton, macrophytes Grazers, collectors, shredders CPOM, phytoplankton, macrophytes

32 Comparing stream & lake communities Small rivers Large rivers Ponds Lakes Benthic production Fish communities Fish production

33 Comparing stream & lake communities Small rivers Large rivers Ponds Lakes Benthic production Fish communities Fish production Low High High Low

34 Comparing stream & lake communities Small rivers Large rivers Ponds Lakes Benthic production Fish communities Fish production Low High High Low Few Many Few Many

35 Comparing stream & lake communities Small rivers Large rivers Ponds Lakes Benthic production Fish communities Fish production Low High High Low Few Many Few Many Moderate High Low, moderate Moderate