INVERTEBRATE BIODIVERSITY IN NORTHERN HARDWOOD ECOSYSTEMS UNDER VARYING DISTURBANCE REGIMES. Abstract. Methods. Introduction and Literature Review

Transcription

1 INVERTEBRATE BIODIVERSITY IN NORTHERN HARDWOOD ECOSYSTEMS UNDER VARYING DISTURBANCE REGIMES Holly A. Petrillo nd John A. Witter School of Nturl Resources nd Environment, University of Michign Astrct During we re investigting the effects of forest type, forest stnd chrcteristics, eech rk disese (BBD) nd mechnicl thinning on the iodiversity of ground-dwelling rthropods in northern hrdwood stnds in Michign. This study is lso exmining the reltionship etween downed woody deris nd inverterte iodiversity within forest stnd. The gol of this reserch is to help explin the complex reltionships nd interctions etween ground-dwelling rthropods, forest stnd chrcteristics, nd disturnces in Michign s northern hrdwood forests. Specific reserch questions eing sked include: (1) Wht is the reltionship etween downed woody deris nd grounddwelling rthropod diversity?, (2) Wht is the reltionship etween forest type nd ground-dwelling rthropod diversity? nd (3) Wht is the effect of BBD nd thinning on iodiversity of ground-dwelling rthropods? We re collecting ground-dwelling rthropods using united pitfll trps in 48 northern hrdwood stnds in Michign sed on forest type, presence/ sence of mechnicl thinning, nd presence/ sence of BBD. Ground eetles (Coleopter: Cride), cmel crickets (Orthopter: Gryllcridide) nd sowugs (Crustce: Isopod) re identified to the species level nd re the focl groups of this study. All other ground-dwelling rthropods re grouped nd quntified y txonomic group. A etter understnding of the fctors ffecting diversity of ground-dwelling rthropods is importnt for mngement, conservtion nd the preservtion of iologicl diversity. Introduction nd Literture Review Biodiversity of ground-dwelling rthropods is influenced y oth iotic nd iotic fctors t multiple scles from glol ltitudinl ptterns to locl microhitts within forest stnd. Generliztions cn e mde out ptterns of species distriutions nd diversity on continentl scle, ut ech txonomic group exmined will hve specilized requirements nd slightly different fctors influencing its persistence in the environment. Disturnces, oth nturl nd nthropogenic hve een shown to influence rthropod distriutions, nd certin inverterte groups hve een used to study the impcts of these disturnces nd to mke recommendtions for mngement of distured res (Dvis 2; Werner nd Rff 2; Lewis nd Whitfield 1999; Rodriguez et l. 1998; Niemel et l. 1993; Person nd Cssol 1992; Lenski 1982). Invertertes dominte mny forest ecosystems in terms of species richness nd iomss, nd influence ecosystem processes such s predtion, decomposition, nutrient cycling, nd pollintion (Werner nd Rff 2; Price 1997). Mny studies hve used ground-dwelling rthropods s indictors ecuse of the lrge smple sizes tht cn e otined with reltively unised methods, short genertion times, low dispersl ility which mkes them susceptile to disturnce, nd sensitivity to microsite chnges (McGeoch 1998; Kremen 1994; Kremen et l. 1993). Downed woody deris (DWD) serves s n importnt hitt component for mny inverterte nd verterte groups (Hunter 199). Structurl diversity provided y DWD hs een shown to increse iologicl diversity in forested stnds (McGee et l. 1999). Severl studies hve een conducted to quntify the mount of DWD present in forest ecosystems (Muller 23; Hgn nd Grove 1999; Goodurn nd Lorimer 1998; Guy nd Doertin 1996). Although the importnce of the downed wood resource to plnts nd nimls in these ecosystems is ssumed, most studies do not directly exmine the reltionship etween DWD nd orgnism use. Mnging for DWD hs ecome recognized s necessry for mintennce of iodiversity; mngement ctivities such s thinning cn hevily impct mounts of DWD in forest stnd (Hgn nd Grove 1999). Methods This study exmines the fctors influencing diversity of ground-dwelling rthropods nd is investigting inverterte iodiversity under vrying disturnce regimes in northern hrdwood stnds in Michign. Forty-eight northern hrdwood stnds re used in this study; 24 stnds re locted in the northern Lower Peninsul (LP) nd 24 stnds re locted in the estern Upper Peninsul (UP) (Figure 1). Dominnt overstory tree species include Americn eech (Fgus grndifoli 88

2 Tle 1. Downed woody deris (DWD) smpling clsses DWD clss Quntity/ Qulity of DWD Very low volume of DWD (smll rnches nd twigs) 1 One lrge tree (> 2 cm DBH, >3 m long) in erly decy stges 2 One lrge tree (> 2 cm DBH, > 3 m long) with dvnced decy 3 Two lrge trees (> 2 cm DBH, > 3 m long) in erly decy stges 4 Two lrge trees (> 2 cm DBH, > 3 m long) with dvnced decy Figure 1. Loction of reserch stnds in the iodiversity study in Michign. Ehrh.), sugr mple (Acer scchrum Mrsh.), northern red ok (Quercus rur L.) nd red mple (Acer rurum L.). Tretment types in this study involve comintion of two fctors: (1) presence or sence of exotic eech scle nd (2) forest type (mple-eech, ok-eech) (LP) or silviculturl tretment (two levels: no silviculturl tretment, selection cut (5 yers prior to dt collection) (UP)). Ten united pitfll trps re plced 4 m prt long trnsects within ech stnd. Trps re opened for 3 dys ech month during mid-june, mid-july nd mid-august. Collected orgnisms re counted nd grouped y mjor tx. The ground eetles (Coleopter: Cride), cmel crickets (Orthopter: Gryllcridide) nd sowugs (Crustce: Isopod) re further identified to the species level. Spiders (Arnee), millipedes (Diplopod), centipedes (Chilopod) nd lnd snils nd slugs (Gstropod) re identified to the fmily level. For the downed wood study, piles of wood found nturlly in stnd re used. Piles re chosen sed on four clsses of DWD tht vry y volume nd decy clss (Tle 1). Pitfll trps re plced s close to the center of the DWD s possile nd trp ctches re compred mong the different clsses of DWD. Five replictes of ech of the clsses re chosen within ech stnd nd eight stnds in the UP were selected for this prt of the study. Four of the stnds hve hevy BBD where mortlity of overstory eech hs lredy occurred nd four stnds re not infested with BBD. Pitfll trp ctches will e compred etween the different DWD clsses to determine if different inverterte groups nd/or species re utilizing different volumes nd decy clsses of downed wood. Preliminry Results nd Discussion Significntly more individul rthropods were cught in pitfll trps in August compred to June nd July (Figure 2). No significnt differences were found etween the numer of rthropods in plots with nd without eech scle. In the Lower Peninsul ok-eech stnds without Men # indiv/ plot June July August Figure 2. Men numer of individul rthropods per plot in June, July nd August 23 in Michign. Brs indicte stndrd errors. Different letters indicte men vlues tht re significntly different mong months. 89

3 eech scle present hd significntly more rthropods compred to ok-eech stnds with eech scle nd mple-eech stnds with nd without eech scle (Figure 3). In the Upper Peninsul no significnt differences were found etween the numer of rthropods in thinned or unthinned stnds with nd without eech scle. Significntly more crid eetles were cught in pitfll trps in August compred to June nd July (Figure 4). No significnt differences were found etween the numer of crid eetles in plots with nd without scle. In the Lower Peninsul no significnt differences were found etween numers of crid eetles in ok-eech or mple-eech stnds with or without eech scle. In the Upper Peninsul significntly more crid eetles were found in unthinned stnds compred to thinned stnds (Figure 5). Conclusion This reserch is continuing through 26. Preliminry results show no effect of BBD or mechnicl thinning on numer of rthropods cught in pitfll trps. Once individuls re identified to species, we will determine if species shifts occur s result of hitt chnges due to BBD or thinning. Reserch during summer 25 will focus on ground eetles, cmel crickets nd sowugs t the species level nd the reltionship etween rthropods nd downed woody deris. Acknowledgments We thnk the USDA McIntire-Stennis Progrm, the USDA Forest Service, Michign Deprtment of Nturl Resources Forest, Minerl nd Fire Mngement Division, Michign Chpter of the Nture Conservncy, University of Michign Biologicl Sttion, nd the University of Michign School of Nturl Resources nd Environment for finncil support for this reserch. Men # indiv/ plot OB, no scle OB, scle MB, no scle MB, scle Figure 3. Men numer of individul rthropods per plot in ok-eech (OB) nd mple-eech (MB) stnds with nd without eech scle present in Michign. Brs indicte stndrd errors. Different letters indicte men vlues tht re significntly different within ech scle rting nd forest type. Crid eetles/ trp June July August Figure 4. Men numer of crid eetles (Coleopter: Cride) per plot in June, July nd August 23 in Michign. Brs indicte stndrd errors. Different letters indicte men vlues tht re significntly different mong months. Crid eetles/ plot No Thin Thin Figure 5. Men numer of crid eetles (Coleopter: Cride) per plot in June, July nd August 23 in Michign. Brs indicte stndrd errors. Different letters indicte men vlues tht re significntly different y tretment. 9

4 Literture Cited Dvis, A.J. 2. Does reduced-impct logging help preserve iodiversity in tropicl rinforests? A cse study from Borneo using dung eetles (Coleopter: Screoide) s indictors. Environmentl Entomology 29, Goodurn, J.M. nd C.G. Lorimer Cvity trees nd corse woody deris in old-growth nd mnged northern hrdwood forests in Wisconsin nd Michign. Cndin Journl of Forest Reserch 28, Guy, N.A.B. nd M. Doertin Quntittive estimtes of corse woody deris nd stnding dedtrees in selected Swiss forests. Glol Ecology nd Biogeogrphy Letters 5, Hgen, J.M. nd S.L. Grove Corse woody deris: Humns nd nture competing for trees. Journl of Forestry 97, Hunter, M.L., Jr Wildlife, forests, nd forestry: Principles of mnging forests for iologicl diversity. Prentice-Hll Creer & Technology, Englewood Cliffs, NJ. 37 p. Kremen, C Biologicl inventory using trget tx: cse study of the utterflies of Mdgscr. Ecologicl Applictions 4, Kremen, C., R.K. Colwell, T.L. Erwin, D.D. Murphy, R.F. Noss, nd M.A. Snjyn Terrestril rthropod ssemlges: their use in conservtion plnning. Conservtion Biology 7, Lenski, R.E Effects of forest cutting on two Crus species: evidence for competition for food. Ecology 63, Lewis, C.N. nd J.B. Whitfield Brconid wsp (Hymenopter: Brconide) diversity in forest plots under different silviculturl methods. Environmentl Entomology 28, McGee, G.G., D.J. Leopold, nd R.D. Nylnd Structurl chrcteristics of old-growth, mturing, nd prtilly cut northern hrdwood forests. Ecologicl Applictions 9, McGeoch, M.A The selection, testing, nd ppliction of terrestril insects s ioindictors. Biologicl Review 73, Muller, R.N. 23. Lndscpe ptterns of chnge in corse woody deris ccumultion in n oldgrowth deciduous forest on the Cumerlnd Plteu, southestern Kentucky. Cndin Journl of Forest Reserch 33, Niemel, J., D. Lngor nd J.R. Spence Effects of cler-cut hrvesting on orel ground-eetle ssemlges (Coleopter: Cride) in western Cnd. Conservtion Biology 7, Person, D.L. nd F. Cssol World-wide species richness ptterns of tiger eetles (Coleopter: Cicindelide): Indictor txon for iodiversity nd conservtion studies. Conservtion Biology 6, Price, P.W Insect Ecology, 3rd ed. John Wiley & Sons, Inc. New York, NY. 874 p. Rodriguez, J.P., D.L. Person, nd R. Brrer R A test for the dequcy of ioindictor tx: re tiger eetles (Coleopter: Cicindelide) pproprite indictors for monitoring the degrdtion of tropicl forests in Venezuel? Biologicl Conservtion 83, Werner, S. M. nd K. F. Rff. 2. Effects of forest mngement prctices on the diversity of groundoccurring eetles in mixed northern hrdwood forests of the Gret Lkes Region. Forest Ecology nd Mngement 139,

5 Evns, Celi A., Lucs, Jennifer A. nd Twery, Mrk J. 25. Beech Brk Disese: Proceedings of the Beech Brk Disese Symposium. Gen. Tech. Rep. NE-331. Newtown Squre PA, US. Deprtment of Agriculture Forest Service, Northern Reserch Sttion. 149 p. Contins invited ppers, short contriutions, strcts, nd working group summries from the Beech Brk Disese Symposium in Srnc Lke, NY, June 16-18, 24. Key Words: Beech Brk Disese, forest structure, wildlife, silviculture nd mngement, genetics, Northestern forests, reserch gend, Cryptococcus fgisug, Nectri coccine vr. fgint, Fgus grndifoli Printed on Recycled Pper