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Trait-based Analyses for Fishes and Invertebrates in Streams Mark Pyron

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Presentation on theme: "Trait-based Analyses for Fishes and Invertebrates in Streams Mark Pyron"— Presentation transcript:

1 Trait-based Analyses for Fishes and Invertebrates in Streams Mark Pyron

2 River Habitat Templet Ideas for species traits-environmental filters (from Southwood 1977; used by Poff 1997)

3 Why Traits? Compare evolutionarily distinct systems Species-habitat relationships Ecosystem processes

4 Major assumption! Present day habitat conditions match present day traits in organisms

5 Which traits? Which analyses? What are results? What are problems?

6 Which traits? Spatial and temporal heterogeneity of habitat define where and when the organisms use habitat

7 Traits: Should vary with ecological gradients

8 and... Organisms with same traits occur in multiple biogeographical regions – Different taxa

9 Traits of macroinvertebrates Trophic – Shredders, filterer-collector, grazer, predator Locomotion Body size Voltinism Respiration technique

10 Traits of macroinvertebrates Life history: reproductive strategies – Body size – Egg size, number, shape, attachment – Generations / year – Oviposition period -season – Incubation time – Clutch number

11 Traits of fishes Habitat preferences: – Stream size (small, medium, large) – Discharge – Temperature – Depth – Substrate size – Canopy

12 Traits of fishes Life history – Body size – Lifespan – Age at maturity – Egg size – Fecundity

13 Traits of fishes Dispersal ability Colonization ability

14 Traits of fishes Reproductive guilds IBI metrics Feeding and ecosystem interactions Morphology

15 Analyses – patterns Heino et al. 2013

16 Across catchment – RCC predictions – Do organisms respond same to environmental gradient?

17 Analyses – patterns Heino et al. 2013 Across catchment Among region differences or convergence – Same traits in different local communities? – Compare trait responses to same gradients in different geographical regions

18 Analyses – patterns Heino et al. 2013 Across catchment Among region differences or convergence Across community – large extent or w/in catchment – Trait variation across local communities in drainage basin at large geographical extent

19 Analyses – tests Heino et al. 2013 Indirect ordination: CA, PCA Direct ordination: CCA, RDA, RLQ Group test: MRPP Life history strategy: ANOVA Niche Model: Maximum Entropy Trait diversity: regression, ANOVA

20 Results: macroinvertebrate traits Human impacts – Traits discriminate river reaches – Taxonomy could not – Genus level or family level sufficient – Gayraud et al. 2003

21 Results: macroinvertebrate trait richness Increases along local, catchment, and geographical gradients Bêche & Statzner 2009

22 Results: macroinvertebrate traits studies Trait richness correlated with genus richness Beche & Statzner 2009

23 Results: fish traits Hydrologic variability: – Resource generalists vs. specialists – Poff & Allan 1995

24 Results: fish traits Hydrologic variability: – Life-history traits – Tedesco et al. 2008; Mims & Olden 2012

25 Results: fish traits studies Taxonomy explains regional / geographic distributions of fishes Traits better explain local habitat type and stability, and regional distribution Hoeinghaus et al. 2006

26 Results: fish traits studies Difference in fish traits across river basins – Result of glaciation: filter – Colonizers had opportunistic traits: small body size, brief lifespan, low age maturity, small eggs – Mims et al. 2010 – Jacquemin and Pyron 2011

27 Traits vs. taxa respond similarly to gradients? – Predicted by Heino et al. 2013: – Traits insensitive to geographical variation – Taxa more geographically structured Depends on spatial extent of study

28 Problems with traits Developmental trophic changes Poorly known taxa; broad family characterizations often incorrect Traits are intercorrelated: not independent

29 Problems with traits Data quality of traits varies – Fuzzy coding, continuous variables, categories

30 Summary Functional traits are useful Tend to respond more strongly to environmental gradients than taxonomy – Taxonomy is successful at distinguishing large- scale assemblage variation

31 Traits studies Gayraud et al. 2003 Goldstein & Meador 2005 Hoeinghaus et al. 2007 Frimpong & Angermeier 2010 Menezes et al. 2010 Pyron et al. 2011 Jacquemin & Pyron 2011 Pease et al. 2012 Heino et al. 2013

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