Evaluating spatial autocorrelation and depletion in pitfall-trap studies of environmental gradients
Received: 29 August 2005 Accepted: 12 January 2006 DOI:
10.1007/s10841-006-0016-8 Cite this article as: Baker, S.C. & Barmuta, L.A. J Insect Conserv (2006) 10: 269. doi:10.1007/s10841-006-0016-8 Abstract
Studies of environmental gradients like edge effects commonly employ designs where samples are collected at unequal distances within transects. This approach risks confounding species patterns caused by the environmental gradient with patterns resulting from the spatial arrangement of the sampling scheme. Spatial autocorrelation and depletion (reduced catch) have the potential to influence pitfall-trap collections of invertebrates. Readily available control data from a study of edge and riparian effects on forest litter beetles was used to assess autocorrelation and depletion effects. Data from control transects distant from the treatment transects located at habitat edges and streams were screened to determine whether the study design (pitfall traps at varying distances within transects) was imposing patterns on the data attributable to differential autocorrelation or depletion. Autocorrelation in species composition and assemblage structure was not detected within the 99 m transects. The abundance and species richness of beetles were not lower where traps were in closer proximity, indicating that the transect design was not causing measurable depletion or resulting in differential trap catch. These findings indicate that spatial autocorrelation and depletion are unlikely to impair further analyses of edge and riparian effects on litter beetles.
Keywords Coleoptera Edge effects Spatial structure Species abundance pattern Transects References Baker, S.C., Richarsdon, A.M.M., Seeman, O.D., Barmuta, L.A. 2004 Does clearfell, burn and sow silviculture mimic the effect of wildfire? A field study and review using litter beetles For. Ecol. Manage. 199 433 448 Google Scholar Bedford, S.E., Usher, M.B. 1994 Distribution of arthropod species across the margins of farm woodlands Agric. Ecosyst. Environ. 48 295 305 CrossRef Google Scholar
Briggs J.B. 1961. A comparison of pitfall trapping and soil sampling in assessing populations of two species of ground beetles (Col.: Carabidae). Report of East Malling Research Station for 1960, pp. 108–112.
Dalthorp, D. 2004 The generalized linear model for spatial data: assessing the effects of environmental covariates on population density in the field Entomol. Exp. Appl. 111 117 131 CrossRef Google Scholar Dangerfield, J.M., Pik, A.J., Britton, D., Holmes, A., Gillings, M., Oliver, I., Briscoe, D., Beattie, A.J. 2003 Patterns of invertebrate biodiversity across a natural edge Austral Ecol. 28 227 236 CrossRef Google Scholar Davies, K.F., Margules, C.R., Lawrence, J.F. 2004 A synergistic effect puts rare, specialized species at greater risk of extinction Ecology 85 265 271 Google Scholar Davison, A.C., Hinkley, D.V. 1997Bootstrap Methods and Their Application Cambridge University Press Cambridge, UK Google Scholar Didham, R.K., Hammond, P.M., Lawton, J.H., Eggleton, P., Stork, N.E. 1998 Beetle species responses to tropical forest fragmentation Ecol. Monogr. 68 295 323 CrossRef Google Scholar Digweed, S.C., Currie, C.R., Cárcamo, H.A., Spence, J.R. 1995 Digging out the “digging-in effect” of pitfall traps: influences of depletion and disturbance on catches of ground beetles (Coleoptera: Carabidae) Pedobiologia 39 561 576 Google Scholar Downes, B.J., Barmuta, L.A., Fairweather, P.G., Faith, D.P., Keough, M.J., Lake, P.S., Mapstone, B.D., Quinn, G.P. 2002Monitoring Ecological Impacts: Concepts and Practice in Flowing Waters Cambridge University Press Cambridge, UK Google Scholar Greenslade, P.J.M. 1964 Pitfall trapping as a method for studying populations of Carabidae (Coleoptera) J. Anim. Ecol. 33 301 310 CrossRef Google Scholar Greenslade, P.J.M. 1973 Sampling ants with pitfall traps: digging-in effects Insect. Soc. 20 343 353 CrossRef Google Scholar Greenslade, P., Greenslade, P.J.M. 1971 The use of baits and preservatives in pitfall traps J. Aust. Ent. Soc. 10 253 260 Google Scholar Keitt, T.H., Bjornstad, O.N., Dixon, P.M., Citron-Pousty, S. 2002 Accounting for spatial pattern when modeling organism–environment interactions Ecography 25 616 625 CrossRef Google Scholar Kotze, D.J., Samways, M.J. 2001 No general edge effects for invertebrates at Afromontane forest/grassland ecotones Biodivers. Conserv. 10 443 466 CrossRef Google Scholar Legendre, P. 1993 Spatial autocorrelation: trouble or new paradigm? Ecology 74 1659 1673 CrossRef Google Scholar Leponce, M., Theunis, L., Delabie, J.H.C., Roisin, Y. 2004 Scale dependence of diversity measures in a leaf-litter ant assemblage Ecography 27 253 267 CrossRef Google Scholar Luff, M.L. 1968 Some effects of formalin on the numbers of Coleoptera caught in pitfall traps Entomol. Mon. Mag. 104 115 116 Google Scholar Luff, M.L. 1975 Some features influencing the efficiency of pitfall traps Oecologia 19 345 357 Google Scholar Magurran, A.E. 2004Measuring Biological Diversity Blackwell Malden, MA Google Scholar Melbourne, B.A. 1999 Bias in the effect of habitat structure on pitfall traps: an experimental evaluation Aust. J. Ecol. 24 228 239 CrossRef Google Scholar Niemelä, J. 1990 Spatial distribution of carabid beetles in the southern Finnish taiga: the question of scale Stork, N.E. eds. The Role of Ground Beetles in Ecological and Environmental Studies Intercept Hampshire, UK 143 155 Google Scholar Niemelä, J., Haila, Y., Puntilla, P. 1996 The importance of small-scale heterogeneity in boreal forests: variation in diversity in forest-floor invertebrates across the succession gradient Ecography 19 352 368 CrossRef Google Scholar
Oksanen J. 2004. Vegan: community ecology package. R package version 1.6–4.
Perner, J., Schueler, S. 2004 Estimating the density of ground-dwelling arthropods with pitfall traps using a nested-cross array J. Anim. Ecol. 73 469 477 CrossRef Google Scholar R Development Core Team 2003R: a language and environment for statistical computing R Foundation for Statistical Computing Vienna, Austria Google Scholar Rieske, L.K., Buss, L.J. 2001 Influence of site on diversity and abundance of ground- and litter-dwelling Coleoptera in Appalachian oak-hickory forests Environ. Entomol. 30 484 494 CrossRef Google Scholar Sanderson, R.A., Rushton, S.P., Cherril, A.J., Byrne, J.P. 1995 Soil, vegetation and space: an analysis of their effects on the invertebrate communities of a moorland in north-east England J. Appl. Ecol. 32 506 518 CrossRef Google Scholar Spence, J.R., Niemelä, J.K. 1994 Sampling carabid beetle assemblages with pitfall traps: the madness in the method Can. Entomol. 126 881 894 Google Scholar Wagner, H.H. 2004 Direct multi-scale ordination with canonical correspondence analysis Ecology 85 342 351 Google Scholar Ward, D.F., New, T.R., Yen, A.L. 2001 Effects of pitfall trap spacing on the abundancerichness and composition of invertebrate catches J. Insect Conserv. 5 47 53 CrossRef Google Scholar Welsh, A.H., Cunningham, R.B., Donnelley, C.F., Lindenmayer, D.B. 1996 Modelling abundance of rare species: statistical models for counts with extra zeros Ecol. Model. 88 297 308 CrossRef Google Scholar