Long term Studies of Macroinvertebrate Responses to Harvest in Hinkle, Alsea and Trask watersheds

Transcription

1 Long term Studies of Macroinvertebrate Responses to Harvest in Hinkle, Alsea and Trask watersheds Judith Li, William Gerth, Janel Sobota, Richard VanDrieschegBateman Department of Fisheries & Wildlife, OSU and Doug Bateman, Dept. of Forest Engineering, OSU

2 Differences between Study Watersheds Site Characteristics Hinkle Trask Alsea # invertebrate sites WS area (sq. km) Geology Basalt Mixed Sandstone Elevation (m) Percent slope Avg. Annual precip (in) Aug avg daily max temp Jan avg daily min temp C C C C C C

3 Site Characteristics Hinkle Trask Alsea # invertebrate sites WS area (sq. km) Geology largest Basalt Mixed Elevation (m) Greatest range, Percent slope Some sites steepest highest Similar to Hinkle small TyeeSandstone lowest Least gradient Avg. Annual precip (in) least greatest Similar to Hinkle Aug avg daily max temp Jan avg daily min temp C C warmest cooler C C coldest C C warmest

4 How do patterns of benthic invertebrates in these watersheds compare? How will they respond to harvest?

5 Characteristics of Stream Invertebrates 1. High Variation in Densities & Composition Samples with many taxa 2. Variation in Life Histories 3. Variation in Sensitivities Local Longevity v. Colonizers Tolerant v.s. Sensitive

6 Using Diversity & Variation in Study Design Evaluating: Abundance Composition Life Histories Sensitivities Densities, Biomass Taxa at each site (Taxa richness) Relative abundances of taxa Emergence of adults Proportions of tolerant taxa (Chironomids)

7 WRC Sites Study Approach Control, Unlogged v. Logged Sites Before and After Harvest Trask : 4 sub basins 1 control/subasin 7 treated headwaters 4 mainstem Alsea: 1 control tributary 1 upstream logged trib 2 yrs postharvest Hinkle: 7 North Fk control : 3 headwater + 1, 3 mainstem 10 South Fk treated: 4 headwater, (3 dwnstm tribs), 6 mainstem 4 yrs after headwater harvest, 1 yr post mainstem harvest

8 Hinkle Seasonal & Annual Variation in Benthic Densities Benthic invertebrates per square meter (log scale) spring summer fall Unlogged Hinkle headwaters

9 Hinkle: Fish Diet Aquatic prey are important in Spring & Fall Terrestrial prey most of Summer diet 2004

10 A Comparison of Spring Benthic Samples, Unlogged Sites Distinctive Invertebrate Assemblages at Each Watershed (NMS Ordination; each symbol = collection at one site) WS_Year 0.5 Juga Pristinicola Hinkle 2007 Hinkle 2008 Alsea 2007 Alsea 2008 Trask s i x A -0.5 Paraleptophlebia Tanypodinae Acari Lepidostoma Optioservus / Heterlimnius Ameletus Epeorus Ironodes Rhyacophila Baetis Axis 1

11 Benthic densities at Hinkle headwaters were lower More variable at Trask Hinkle no log Alsea Trask preharvest preharvest

12 Among Non Rare Invertebrates ( 1% at a Site) Few Found In Common at All 3 WRC watersheds Benthics: 3 Mayflies 1 Stonefly 1 Chironomid tribe Oligochaete (worms) Emergent Adults: 3 Mayflies 3 Caddisflies

13 Differences between Headwaters and Mainstems at Hinkle & Trask (preharvest): Density, Percent Chironomidae & Taxa Composition NMS Summer Trask Headwater Downstream Axis 3(R 2 =0.209) Tanypodinae Ostracoda Drunella Baetis Malenka, Epeorus, Rhyacophila Cinygmula Yoraperla Axis 1 (R 2 =0.428)

14 ) Assessing Effects of Harvest Hinkle Creek 2005 in Tributaries North Fork: 4 Control reaches South Fork: 4 Headwaters harvested 2008 Harvest in Mainstem North Fork: 3 Control reaches South Fork: 6 Harvested reaches

15 Hinkle: Effects of Harvest on Taxa Composition 1.5 harvest harvested not harvested Baetis 0.5 Epeorus Axis 3 Orthocladiinae Visoka Cinygmula Sweltsa/Alloperla Nematoda Tanypodinae Pisidiidae Oligochaeta Pristinicola Axis 1

16 Invertebrate Response in Hinkle Headwaters: Densities Increased Benthic invertebrates per square meter Preharvest: No difference headwater logging control treatment

17 Invertebrate Response in Hinkle Headwaters: Percent Chironomids Increased, Taxa Richness Decreased Benthic percent chironomids control treatment Benthic taxa richness control treatment headwater logging

18 Benthic invertebrates per square meter Hinkle Tributaries with Fish: No downstream effects on invertebrates after harvest in headwaters control treatment Benthic densities (in this graph), percent chironomids and taxa richness did not differ significantly from controls

19 Hinkle Mainstem Invertebrate Responses: Percent Chironomids Increased 100 Benthic percent chironomids 10 control treatment Benthic taxa richness Taxa Richness Decreased control treatment

20 Fish at Hinkle Mainstem: Diet responded to Increase in chironomids 80 Benthic percent chironomids Fish gut content percent chironomids headwater logging MS logging & dam-break flood

21 Mainstem Responses: Benthic Densities DID NOT Increase Benthic invertebrates per square meter control treatment headwater logging MS logging and dam break flood

22 South Fork Hinkle: No Detected Change in Benthic Density May be Explained by Increase in Fish Biomass

23 Invertebrate Mainstem Responses: Adult Aquatic Emergence Increased Aquatic insect emergence rate number/square meter/day control treatment headwater logging MS logging and dam break flood

24 60 Hinkle & Alsea Aquatic Emergence 2009 Higher Emergence at Logged Sites Individuals/m 2 /day Hinkle Unlogged Hinkle Logged Flynn Needle Branch

25 Alsea: Few detectable differences postharvest at Needlebranch High variation between sites, fewer replicates Benthic invertebrates per square meter (log scale) Flynn Needlebranch headwater logging

26 Alsea: Cutthroat diet after harvest Average fish diet composition 100% 80% 60% 40% 20% unknown terrestrials adult aquatics aquatics 0% Flynn NB Flynn NB

27 Trask: Seasonal & Annual Variation in Emergence Detecting Changes in Life Histories Emergence of Aquatic Insects Trask Individuals/m2/day /26 7/6 7/16 7/26 8/5 8/15 8/25 9/

28 Trask: Measuring Benthic Biomass Contributions to Stream Productivity 1.6 Trask Biomass Headwater Downstream Benthic Biomass (g)/m2 Mean + S.E April June Aug/Sept

29 WRC Sites Study Designs: Key to Detecting Differences Alsea: limited samples More years, WRC context important Trask : Controls within sub basin Expanded measurements life histories, productivity Hinkle: High replication in space & time Significant differences adjacent to harvest Coordinated sampling suggest connections to fish consumption

30 Field and lab assistants: Thanks to many Linda Ashkenas, Jenny Ruthven, Jenn King, Phil Brown, Anthony Olegario, Katie Whitehead, Pete Ober, Lance Wyss, Jeremy Romer, Julie House, Kylie Meyer, Scott Bartle, Chrissy Murphy, Amanda Robillard, Randy Colvin, Lucas Cramer, Asako Yamamuro and others Fish friends: Dave Leer, Steve Clark and the fish crews Statistics consultation: Lisa Ganio Funding: OSU Forest Research Lab Fish and Wildlife Habitat in Managed Forests Research Program Oregon Department of Forestry; Weyerhauser; Roseburg Forest Products, Plum Creek; USGS

31

32 Flynn Alsea Watershed Needle Branch Preharvest study: Small tributaries with fish Flynn Creek 3 reaches no harvest Needlebranch 3 reaches Harvest in 2009 upstream of study reaches

33 Upper Trask Watershed 4 Subbasins, 3 ownerships Preharvest Sampling Harvest 2012 in modified plan 11 Headwater 4 Mainstem Reaches