Trait-based Analyses for Fishes and Invertebrates in Streams Mark Pyron Stoeckerecological.com.
-
Upload
desmond-facey -
Category
Documents
-
view
218 -
download
4
Transcript of Trait-based Analyses for Fishes and Invertebrates in Streams Mark Pyron Stoeckerecological.com.
River Habitat Templet
Ideas for species traits-environmental filters
(from Southwood 1977; used by Poff 1997)
Why Traits?
• Compare evolutionarily distinct systems• Species-habitat relationships
• Ecosystem processes
Which traits?
• Spatial and temporal heterogeneity of habitat define where and when the organisms use habitat
Traits of macroinvertebrates
• Trophic– Shredders, filterer-collector, grazer, predator
• Locomotion
• Body size
• Voltinism
• Respiration technique
Traits of macroinvertebrates
• Life history: reproductive strategies– Body size– Egg size, number, shape, attachment– Generations / year– Oviposition period -season– Incubation time– Clutch number
Traits of fishes
• Habitat preferences:– Stream size (small, medium, large)– Discharge– Temperature– Depth– Substrate size– Canopy
Traits of fishes
• Reproductive guilds
• IBI metrics
• Feeding and ecosystem interactions
• Morphology
Analyses – patterns Heino et al. 2013
• Across catchment– RCC predictions– Do organisms respond same to environmental
gradient?
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
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
Analyses – testsHeino et al. 2013
Indirect ordination: CA, PCADirect ordination: CCA, RDA, RLQGroup test: MRPPLife history strategy: ANOVANiche Model: Maximum EntropyTrait diversity: regression, ANOVA
Results: macroinvertebrate traits
• Human impacts– Traits discriminate river reaches– Taxonomy could not – Genus level or family level sufficient – Gayraud et al. 2003
Results: macroinvertebrate trait richness
• Increases along local, catchment, and geographical gradients
• Bêche & Statzner 2009
Results: macroinvertebrate traits studies
• Trait richness correlated with genus richness Beche & Statzner 2009
Results: fish traits
• Hydrologic variability:
– Resource generalists vs. specialists – Poff & Allan 1995
Results: fish traits
• Hydrologic variability:
– Life-history traits – Tedesco et al. 2008; Mims & Olden 2012
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
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
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
Problems with traits
• Developmental trophic changes
• Poorly known taxa; broad family characterizations often incorrect
• Traits are intercorrelated: not independent
Problems with traits
• Data quality of traits varies– Fuzzy coding, continuous variables, categories
Summary
• Functional traits are useful
• Tend to respond more strongly to environmental gradients than taxonomy
– Taxonomy is successful at distinguishing large-scale assemblage variation