Ecological Archives A021-009-A5

**Annika W. Walters and David M. Post. 2011. How low can you go? Impacts of a low-flow disturbance on aquatic insect communities. Ecological Applications 20:163–174.**

Appendix E (TABLE E1). Linear model analysis results of insect community metrics and functional feeding group density for pool and riffle habitats.¹

	Riffle habitats			Pool habitats
	slope	R²	P	slope	R²	P
Community metrics
Total density (individuals/0.1 m²)	negative	0.27	0.02	positive	0.01	0.29
Family richness	negative	-0.07	0.84	positive	-0.06	0.69
EPT richness	negative	-0.03	0.49	negative	-0.06	0.77
Family diversity	positive	0.64	<0.001	positive	-0.06	0.66
Family dominance	negative	0.25	0.03	negative	-0.07	0.98
Functional feeding group density (individuals/0.1m²)
Collector-filterer	negative	0.40	0.005	negative	-0.05	0.59
Collector-gatherer	negative	0.16	0.07	positive	0.13	0.09
Scraper	negative	0.36	0.009	negative	0.03	0.26
Shredder	positive	-0.01	0.38	positive	0.12	0.10
Predator	positive	0.16	0.07	positive	0.34	0.01

TABLE E2. Linear model analysis results of family insect density and average insect body size in pool and riffle habitats.²

			Density (individuals/m²)			Size (mm)
Habitat	Family	Order	slope	R²	P	slope	R²	P
Pool	Baetidae	Ephemeroptera	positive	0.00	0.31	positive	-0.16	0.69
communities	Capniidae	Plecoptera	negative	0.33	0.01	negative	0.5	0.11
	Chironomidae	Diptera	positive	0.28	0.02	positive	0.13	0.09
	Chloroperlidae	Plecoptera	positive	-0.04	0.53	negative	-0.12	0.50
	Corydalidae	Megaloptera	positive	0.01	0.29	negative	-0.08	0.56
	(larvae)	Coleoptera	positive	0.18	0.06	positive	-0.09	0.82
	Ephemerellidae	Ephemeroptera	positive	0.27	0.02	negative	0.10	0.18
	Gomphidae	Odonata	positive	0.18	0.05	negative	-0.32	0.86
	Heptageniidae	Ephemeroptera	negative	0.25	0.03	negative	0.05	0.20
	Hydropsychidae	Trichoptera	positive	-0.07	0.92	negative	-0.04	0.50
	Leptophlebiidae	Ephemeroptera	negative	-0.05	0.60	negative	-0.08	0.70
	Leuctridae	Plecoptera	positive	0.25	0.25	positive	0.06	0.21
	Perlidae	Plecoptera	positive	-0.04	0.52	negative	0.12	0.16
	Philopotamidae	Trichoptera	negative	0.25	0.03	negative	0.48	0.08
	Polycentropodidae	Trichoptera	negative	-0.07	0.88	negative	0.38	0.03
	Psephenidae	Coleoptera	negative	-0.07	0.95	positive	0.05	0.21
	Sialidae	Megaloptera	positive	0.09	0.13	positive	-0.14	0.72
	Tipulidae	Diptera	positive	0.22	0.04	positive	-0.02	0.42
Riffle	Baetidae	Ephemeroptera	negative	-0.07	0.82	negative	0.10	0.16
communities	Chironomidae	Diptera	negative	0.05	0.21	negative	0.14	0.08
	Chloroperlidae	Plecoptera	positive	0.00	0.32	negative	0.17	0.09
	Corydalidae	Megaloptera	negative	-0.07	0.82	negative	-0.09	0.83
	(adult)	Coleoptera	negative	-0.07	0.80	positive	-0.07	0.74
	(larvae)	Coleoptera	positive	0.18	0.06	positive	-0.08	0.87
	Glossomatidae	Trichoptera	positive	0.00	0.34	positive	-0.11	0.54
	Heptageniidae	Ephemeroptera	negative	0.46	0.002	negative	0.06	0.19
	Hydropsychidae	Trichoptera	negative	0.04	0.22	negative	0.54	<0.001
	Leptophlebiidae	Ephemeroptera	negative	0.13	0.10	negative	0.07	0.17
	Leuctridae	Plecoptera	positive	0.12	0.10	positive	0.06	0.61
	Peltoperlidae	Plecoptera	negative	0.14	0.09	negative	-0.05	0.45
	Perlidae	Plecoptera	positive	0.15	0.08	negative	0.17	0.06
	Perlodidae	Plecoptera	negative	-0.06	0.68	negative	0.44	0.13
	Philopotamidae	Trichoptera	negative	0.65	<0.001	negative	-0.01	0.39
	Polycentropodidae	Trichoptera	positive	0.04	0.23	negative	0.05	0.22
	Psephenidae	Coleoptera	negative	-0.06	0.70	positive	0.01	0.32
	Rhyacophilidae	Trichoptera	negative	-0.02	0.43	negative	0.19	0.16
	Sialidae	Megaloptera	positive	-0.04	0.50	positive	-0.07	0.59
	Simuliidae	Diptera	negative	0.41	0.005	negative	0.56	0.05
	Tipulidae	Diptera	positive	0.00	0.34	negative	0.07	0.16
	Veliidae	Hemiptera	positive	0.19	0.05	positive	-0.07	0.95

¹A positive slope means that the community metric or functional feeding group density increased at lower flow levels. All August 2005, 2006, and 2007 stream reaches with discharge data are included. Significant P values at the 0.05 level are denoted in bold.

²A positive slope means that insect density or body size increased at lower flow levels. All August 2005, 2006, and 2007 stream reaches with discharge data are included. Insect families that had density and body size data for fewer than five stream reaches are not included in the table. Significant P values at the 0.05 level are denoted in bold.

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