Beetles and Spiders as Indicators of Forest Recovery on Prince of Wales Island, Alaska Jill Stockbridge, MS Student Department of Biology and Wildlife University of Alaska Fairbanks Dictyoptera aurora Cybaeus reticulatus Trichalophus didymus Photo by Derek Sikes Photo by Derek Sikes Photo by Derek Sikes Introduction • Harvesting trees -Significant human disturbance • Converts old growth stands to: - Clear cuts - Young even-aged stands • Decline of old growth forest specialists Old Growth Old Growth Clear Cut Secondary Growth Background • Intensive logging in Tongass National Forest in 1950s - Created 430,000 acres of young even- aged forest stands (McClellan 2007) • Forest management program in 2001: - Tongass-Wide Young-Growth Studies (TWYGS 2008) - Different thinning methods - Hasten recovery process and improve habitat for old growth species (TWGYS 2008) • Some TWYGS sites on Prince of Wales Island, AK Prince of Wales Island Background • Arthropods can be used as ecological indicators -Species that convey information about an ecosystem such as biodiversity or rate of recovery after anthropogenic disturbances (Langor and Spence 2006). • Beetles and spiders as indicators of forest recovery Objectives • Goal: Determine the effects of thinning methods on forest biota 1. Compare beetle and spider species richness, diversity and assemblages of thinned sites to 2nd growth, Old Growth, and Clear Cuts 2. Determine if there are beetles and spiders associated with any forest type Study Design • 3 Controls (6 replicates each): - Old growth - Clear Cuts - Secondary growth • 3 Treatments (2 replicates each): - 14X14’ - 16X16’ - 18X18’ • Total: 24 Sites 14X14 ft. 16X16 ft. 18X18 Ft. Study Design: Unpaired Sites: Clear Cut Clear Cut Thinned 2nd Growth Old Growth Paired Sites: 2nd Growth (Un-thinned) Methods • For all 24 sites: • Samples taken at two-week intervals • Mid-May to mid-August - 2 Lindgren funnels - 4 pairs of pitfall traps - 1 Berlese funnel • 2 years: • 2010 Spider data • 2010 and 2011 Beetle data Methods • Vegetation surveys at each site: -Line transect surveys -Cover of vascular plants -Tree height - Diameter and Breast Height (DBH) -Leaf Area Index (LAI) using linear sensor AccuPAR -Basal Area (BA) Methods: Statistics • Shannon’s Diversity Index (H’) • Species Richness (S) • ANOVA and t-tests • Multi-Dimensional Scaling and Bray-Curtis Similarity Matrix • NPMANOVA and Simper • Vegetation overlays, correlations, BIOENV • Staphylinidae: Aleocharinae removed from analyses • Thinned treatments grouped to increase statistical power Results: Spider data Total: 57 Species 4,805 Adults Results: Spider data Shannon Index with 95% Confidence Intervals 2.3 2.1 H' 1.9 1.7 1.5 2nd Growth Clear Cut Old Growth Thin • No significant Habitat difference in diversity and species richness Species Richness with 95% Confidence between habitats Intervals 24 22 S 20 18 16 2nd Growth Clear Cut Old Growth Thin Habitat Results: Spider data MDS Plot using Bray-Curtis Similarity Matrix Red = Clear Cut, Green = Old Growth, Blue = 2nd Growth, Yellow = Thin Outlier ? Results: Spider data How Species Assemblages Differ Between Habitats • Thins vs. Old Growth • 29 species account for ~90% difference nd • Thins vs. 2 Growth • 27 species account for ~90% difference • Thins vs. Clear Cuts • 32 species account for ~90% difference Results: Spider data How Species Assemblages Differ Between Habitats nd • Species associated with Old Growth and 2 Growth: • Erigoninae sp.1 • Lepthyphantes zibus* • Symmigma minimum* • Species associated with Clear Cuts: • Pardosa dorsuncata • Robertus vigerens • Sisicottus nesides* • Species associated with Thins: • Agyneta sp.1 Lepthyphantes zibus • Centromerus nr. longibulbus • Pocadicnemis pumila • Usofila pacifica Photo by Gerry Blagoev Results: Spider Data Vegetation Overlays Axis 1: 0.545 Axis 1: 0.436 Axis 2: 0.379 Axis 2: 0.267 Axis 1: 0.699 Axis 1: 0.507 Axis 1: -0.336 Axis 2: 0.166 Axis 2: 0.122 Axis 2: -0.678 Spider Results Results: Spider Data BIOENV Variables Size Correlation LAI 1 0.177 LAI Cover 2 0.318 Height LAI Cover 3 0.3265 Height LAI BA Cover 4 0.3178 Height DBH LAI BA Cover 5 0.2383 Results: Beetle data Total: 213 Species 23,586 Individuals Results: Beetle data Shannon Index with 95% Confidence Intervals 3.1 2.9 • No significant H' 2.7 difference in diversity 2.5 between habitats 2.3 2nd Growth Clear Cut Old Growth Thin Habitat Species Richness with 95% Confidence • Significant Intervals difference in 100 a species richness 90 between : ab nd 80 a • 2 growth and S 70 clear cut b nd 60 • 2 growth and 50 old growth 2nd Growth Clear Cut Old Growth Thin Habitat Results: Beetle data MDS Plot using Bray-Curtis Similarity Matrix Red = Clear Cut, Green = Old Growth, Blue = 2nd Growth, Yellow = Thin Results: Beetle data How Species Assemblages Differ Between Habitats nd • Species associated with Old Growth: • Species associated with 2 Growth: • Cryptophagus sp. • Lederia arctica • Dictyoptera simplicipes • Pseudohylesinus sp. • Rhinosimus viridiaeneus • Pterostichus castaneus • Rhizophagus sculpturatus • Pterostichus crenicollis • Scaphinotus angusticollis • Scydmaeninae sp.2 • Scydmaeninae sp.1 • Scydmaeninae sp.3 • Species associated with Clear Cuts: • Sonoma sp. • Ampedus carbonicolor • Staphylinidae sp.15 • Ditylus gracilis • Thins: a mix of species from all other habitats • Listemus acuminatus • Pelecomalium sp. • Punicealis hamata • Rhyncolus brunneus Scaphinotus angusticollis Photo by Derek Sikes Beetle Results Vegetation Correlations Axis 1: -0.073 Axis 1: -0.054 Axis 2: 0.188 Axis 2: 0.337 Axis 1: -0.819 Axis 1: -0.491 Axis 1: 0.155 Axis 2: 0.162 Axis 2: 0.367 Axis 2: -0.322 Beetle Results Results: Beetle Data BIOENV Variables Size Correlation LAI 1 0.4681 LAI Cover 2 0.3966 LAI BA Cover 3 0.3678 DBH LAI BA Cover 4 0.3306 Height DBH LAI BA Cover 5 0.2496 Discussion • GOAL: Determine the effects of thinning methods on forest biota • Not all animals are affected the same by thinning methods • Thins are unique habitat for spiders • Some spiders associated with thins • Thins are not unique habitat for beetles • Thins are not more similar to a specific habitat over another • Thins provide a habitat where species associated from different habitats can co-exist Conclusion • TWYGS Goal: Are thins hastening the recovery process and improving habitat for old growth species? • Thins were not significantly more similar to old growth than other habitats • Pohl et al. (2008) showed similar results for thins/cut stands References: • Langor, D.W., and Spence, J.R. 2006. Arthropods as ecological indicators of sustainability in Canadian forests. The Forestry Chronicle. 82:344-350. • McClellan, M.H. 2007. Adaptive management of young stands on the Tongass National Forest. USDA Forest Service, General Technical Report PNW-GTR-733, Portland Oregon. 225-232. • Pohl, G.R., D. Langor, J. Klimaszewski, T. Work, P. Paquin. 2008. Rove beetles (Coleoptera: Staphylinidae) in northern Nearctic forests. Canadian Entomologist. 140: 415-436. • TWYGS. 2008. U.S. Forest Service. www.fsfed.us/r10/tongass/projects/tlmp/2008_monitoring_report/200 8%20twygs_biodiversity.pdf. {last data accessed: 5 March 2012} Lederia arctica Acknowledgements • Funding from Alaska Department of Fish and Game • Dr. Derek Sikes – major advisor, curator of Entomology at UAM Photo by Casey Bickford • Dr. Jim Kruse and Nick Lisuzzo - USFS Forest Health Protection, Fairbanks • Dr. Diane Wagner - committee member Sisicottus nesides • Tongass National Forest Service • Dr. Liz Flaherty and Dr. Merav Ben-David – University of Wyoming • Joey Slowik – spider specialist Photo by Gerry Blagoev • CASE fellowship program - funding • Casey Bickford, Bennett Wong, Sarah Meierotto, Ian MacDougall, Sayde Ridling- technicians .