Ecology and Condition of the Ground Beetle Scaphinotus Angusticollis
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Ecology and Condition of the Ground Beetle Scaphinotus angusticollis and Distribution of its Prey in Pacific Northwest Riparian Forests by Susanne L. Lavallee B.Sc (University of British Columbia), 1994 M.Sc (University of British Columbia, Zoology), 1999 A THESIS SUBMITTED IN FULFILLMENT OF THE REQUIREMENTS FOR THE DEGREE OF DOCTOR OF PHILOSOPHY In THE FACULTY OF GRADUATE STUDIES (Forestry) THE UNIVERSITY OF BRITISH COLUMBIA September 2006 © Susanne L. Lavallee, 2006 Abstract I studied the population ecology of the flightless, forest-dwelling carabid beetle Scaphinotus angusticollis Fischer Von Waldheim (O. Coleoptera F. Carabidae) and several aspects of its body condition for their associations with forest harvesting. Comparison of population estimates revealed that catch-per-unit-effort estimates were not significantly different from more detailed analyses. In two years of trapping, S. angusticollis population densities were found to be significantly lower in clearcuts, as compared to 30 m riparian reserves and uncut forest, suggesting that riparian buffers provide adequate habitat to maintain populations of this terrestrial insect. Movement of S. angusticollis differed in the three habitats studied between years and treatments, with the greatest movement occurring in 30 m buffers in one year and in control sites the next. Clearcuts had the lowest amount of movement in both years. One of the known prey species for S. angusticollis, snails < 2 cm in diameter, were more abundant in clearcut habitat, with Ancotrema hybridum the most abundant species. Canonical correspondence analysis suggests that only A. hybridum were positively correlated with plant cover, and that other species abundances may rely on coarse, downed wood as cover. Thus only some species of snails are associated with recently logged areas. The internal body conditions of S. angusticollis living in clearcut, 30 m buffer and uncut sites showed that gut fullness was significantly correlated with energy storage (fat body) and habitat types (clearcut, 30 m buffer and uncut). This study demonstrates how some forest insects, particularly ground beetles, are affected by harvesting and that current management practices on the stand scale can mitigate some of the negative impacts of logging. Table of Contents Abstract ii Table of Contents iii List of Tables v List of Figures vi Acknowledgements '. viii Chapter One Introduction 1 Questions 7 Study Organism 8 Literature Cited 9 Chapter Two Evaluation of two population estimate methods for ground beetle (O. Coleoptera, F. Carabidae) populations 16 Introduction 16 Methods '. :....18 Results : 22 Discussion 24 Literature Cited 28 Figures 31 Chapter Three Relative abundance and movement of the carabid beetle Scaphinotus angusticollis in coniferous riparian forests of the Pacific Northwest 33 Introduction 33 Methods 37 Results 42 Discussion 44 Literature Cited .'. 49 Tables 54 Figures 56 Chapter Four Snail (Gastropoda, Pulmonata) abundance and diversity in three forest habitats of Pacific Northwest coniferous forests (Canada) 59 Introduction 59 Methods 61 Results : 63 Discussion .• 64 Literature Cited 68 Tables 70 Figures 71 Chapter Five Forest harvesting and the associated body conditions of the carabid beetle Scaphinotus angusticollis 72 Introduction ; 72 Materials and Methods 75 Results 79 Discussion 84 Literature Cited 88 Tables 92 Figures 96 Chapter Six Conclusion , 99 Findings of this study 99 Use of riparian reserves by forest-preferring species 101 in Use of indicator taxa 102 Contributions to insect ecology and conservation... 103 Literature Cited 106 Appendix I Food preference in Scaphinotus angusticollis (Fischer Von Waldheim) 109 Introduction 109 Methods : 109 Results : 111 Discussion ; 112 Literature Cited 114 iv List of Tables Table 3.1 Analysis of variance of catch per unit effort (CPUE) for Scaphinotus angusticollis in forest, 30 m buffer, and clearcut sites. Main effects include habitat type (H), Site (H), month, the interaction of month and habitat and year. (Model r2 = 0.49, df = 16) ,: .'. .54 Table 3.2 Analysis of variance of catch per unit effort population estimates for Scaphinotus angusticollis in forest, 30 m reserve, and clearcut sites at varying distances from the stream. Main effects include habitat type (H), the nested term of row within habitat type, month, and the interaction of month and habitat. (Model r2 = 0,72, df = 41) 54 Table 3.3 Analysis of variance for distances moved by Scaphinotus angusticollis in clearcut, 30 m reserve and control sites at distances less than 30 m from the stream (close) and greater than 30 m from the stream (far). Main effects include habitat (H), site nested within habitat, and "close or far" nested within habitat. (Model r2 = 0.94, df = 10) 55 Table 3.4 Total number of recaptures of S. angusticollis made in control, 30 m buffer and clearcut sites in 2000 and 2001. Site names are provided under each habitat type •. 55 Table 3.5 Analysis of variance of distances moved by Scaphinotus angusticollis in clearcut, 30 m reserve and control sites. Main effect is habitat only. (Model r2 = 0.07, df = 2) 55 Table 4.1 Canonical correspondence analysis results comparing species occurrences with habitat features (plant cover, coarse woody debris, and fine woody debris)... 70 Table 5.1 Summary of trapping dates and sites, with total number of Scaphinotus angusticollis dissected per time period and site. Zeroes indicate that no individuals were caught 92 Table 5.2 Analysis of variance of gut fullness for Scaphinotus angusticollis in forest, 30 m reserve, and clearcut sites. Main effects include habitat type (H), site nested within habitat, date and the interaction of date and habitat type. (Model r2 = 0.38, df = 14). ; ........... 93 Table 5.3 Analysis of variance of fat body for Scaphinotus angusticollis in forest, 30 m reserve, and clearcut sites. Main effects include habitat type (H), date nested within habitat type, and site nested within habitat type. (Model r = 0.45, df = 14) 93 Table 5.4 Ordinal logistic fit for rank of sex development for Scaphinotus angusticollis in forest, 30 m reserve and clearcut sites. Main effects include habitat type (H), date nested within habitat type, and site nested within habitat type. (Model r2 = 0.43, df = 14) 93 Table 5.5 Analysis of variance results of water content of Scaphinotus angusticollis in forest, 30 m reserve and clearcut sites. Main effects include habitat type (H), site nested within habitat, date and the interaction of date and habitat. (Model r2 = 0.74, df = 14) 94 Table 5.6 Results for analyses of covariance tests of weight/pronotum ratio with gut fullness, fat body, water content and sex Scaphinotus angusticollis 95 List of Figures Figure 2.1 Comparison of population estimates for the adult carabid Scaphinotus angusticollis sampled in 2000 and 2001 in control, 30 m buffer and clearcut habitats. Estimates were made from pitfall trapping and individual marking of beetles. A) Schnabel-Schumacher and CPUE estimates; B) Corrected Schnabel- Schumacher and CPUE estimates; and C) Corrected Schnabel-Schumacher and Schnabel-Schumacher estimates. Dashed line represents 1:1 ratio 31 Figure 2.2 Concordance correlation results, comparing catch-per-unit-effort (CPUE) and Schnabel-Shumacher (SS) population estimates (circles) and catch-per-unit- effort (CPUE) and corrected Schnabel-Schumacher (cSS) population estimates (squares) in each of the three habitats: control, 30 m buffer and clearcut sites 32 Figure 2.3 Concordance correlation analysis results for all Scaphinotus angusticollis population estimates, pooled by year 32 Figure 3.1 Catch-per-unit-effort (CPUE) population estimates (not including any recaptures) of S. angusticollis for control (circle), 30 m buffer (triangle) and clearcut (square) sites in 2000, 2001 and 2002. Error bars indicate standard error. N=3 for all trapping dates except N=2 September/October 2000 and 2002. Asterisk (*) indicates significant difference (p = 0.03) 56 Figure 3.2 Distribution of mean numbers of S. angusticollis caught per trap night in control, 30 m buffer and clearcut habitats in 2000 (A) and 2001 (B) at varying distances from the stream. Dotted line indicates forest boundary in 30 m buffer sites. Error bars represent standard error. (N (number of trapping sessions) = 11 (control 2000) 12 (30 m buffer 2000) 11 (clearcut 2000) and N = 14 (all habitats 2001)) 57 Figure 3.3 Mean distance moved overnight by S. angusticollis in control (circle), 30 m buffer (triangle), and clearcut (square) habitat in 2000 (black) and 2001 (grey). Error bars represent standard error. See Table 3.3 for N of each point 58 Figure 3.4 Mean movement vectors (In) for distances travelled overnight by S. angusticollis in control, 30 m buffer and clearcut sites in 2000 and 2001 (pooled). Error bars represent standard error. N= 7 (clearcut), 26 (30 m buffer), and 15 (control), not weighted by site within habitat 58 Figure 4.1 Mean number of snails found in control, 30m buffer and clearcut habitats along 45 m transects in 2002. N=3 for each habitat type. Error bars indicate standard error 71 Figure 4.2 Mean Shannon-Weaver Diversity Index (FT) values for control, 30m buffer and clearcut site snail diversity in 2003. N=3 for all habitat types, error bars indicate standard error 71 Figure 5.1 Mean total gut fullness (A) and fat body (B) in beetles from control, 30 m buffer and clearcut sites in 2002. N= 2-3, depending on data point; error bars indicate standard error. Asterisk (*) indicates significant difference. 96 Figure 5.2 Mean binary reproductive rank of beetles in control, 30m buffer and clearcut habitats. N = 2-3, depending on data point; error bars indicate standard error 97 Figure 5.3 Water content of beetles controlled for body size (wet - dry weight/ wet weight) from control, 30 m buffer and clearcut habitats in 2002. N = 2-3, depending on data point; error bars indicate standard error. 97 VI Figure 5.4 Mean ln(weight+1)/pronotum ratios (g/cm) for beetles caught in control, 30 m buffer and clearcut habitats in 2000-2002.