Herbivorous Insect Response to Group Selection Cutting in a Southeastern Bottomland Hardwood Forest

Abstract

Malaise and pitfall traps were used to sample herbivorous insects in canopy gaps created by group-selection cutting in a bottomland hardwood forest in South Carolina. The traps were placed at the centers, edges, and in the forest adjacent to gaps of different sizes (0.13, 0.26, and 0.50 ha) and ages (1 and 7 yr old) during four sampling periods in 2001. Overall, the abundance and species richness of insect herbivores were greater at the centers of young gaps than at the edge of young gaps or in the forest surrounding young gaps. There were no differences in abundance or species richness among old gap locations (i.e., centers, edges, and forest), and we collected signiÞcantly more insects in young gaps than old gaps. The insect communities in old gaps were more similar to the forests surrounding them than young gap communities were to their respective forest locations, but the insect communities in the two forests locations (surrounding young and old gaps) had the highest percent similarity of all. Although both abundance and richness increased in the centers of young gaps with increasing gap size, these differences were not signiÞcant. We attribute the increased numbers of herbivorous insects to the greater abundance of herbaceous plants available in young gaps.KEY WORDS selection cutting, uneven-aged silviculture, forest openings, forest management WHILE THE EFFECTS OF insect herbivory on plant communities and rates of succession have been well studied (Breedlove and Ehrlich 1968, Brown 1984, Hendrix et al. 1988, Brown and Gange 1992, McBrien et al. 1983, relatively little is known about how plant succession affects herbivorous insects (Bach 1990). Given the relative abundance of young herbaceous growth in early stages of succession, one might expect to Þnd increased numbers of herbivorous insects there compared with more mature habitats. Indeed, past work recognizes the importance of increasing taxonomic and structural diversity of plants to the creation and maintenance of a diverse insect community during succession (Murdoch et al. 1972, Lawton 1978, Southwood et al. 1979, and several features of the plants themselves may encourage herbivory in recently created habitats. These include increased nutrient levels (i.e., soluble nitrogen) in plant tissues (Boardman 1977, McNeill and Southwood 1978, Mattson 1980, reduced plant defenses in many pioneer species (Coley 1983, Lawton andMcNeill 1979), and increased consumption and growth rates of herbivorous insects that feed on plants receiving direct sunlight (White 1978, Scriber andSlansky 1981). The situation is complicated by a number of factors that seem to discourage herbivory, however. For example, increased light levels may be beneÞcial in terms of insect growth rates, but they have also been shown to increase the toughness of leaves and, in some cases, the concentration of defensive compounds (Shure and Wilson 1993).In many forests, canopy gaps created by treefalls, wind damage, and other minor events serve as important centers of plant growth and su...

The legacy of timber harvest: Do patterns of species dominance suggest recovery of lepidopteran communities in managed hardwood stands?

“…Similar results have been obtained from studies of insect communities on Quercus alba sampled across a large chronosequence (Forkner et al, 2006;Jeffrics et al, 2006) and insect communities occurring in restored deciduous forests (Holl, 1996;Goßner et al, 2008). Species richness of forest insects appears to recover from a disturbance such as timber harvest relatively quickly (<10 years; see Summerville and Crist, 2002;Ulyshen et al, 2005), while community composition tends to bear a lasting imprint of forest management (see also Holl, 1996;. Importantly, the assumption that forest stands that have been unlogged for long time periods are ''control'' sites for comparisons to recently managed stands (e.g., Summerville and Crist, 2002) appears tenuous.…”

Influence of harvest gaps and coarse woody material on click beetles (Coleoptera: Elateridae) in Maine’s Acadian forest

“…Second, the maximum area of the harvest gaps was small, so that even the largest gaps were still influenced by the surrounding stand. However, an experiment in a bottomland hardwood forest in South Carolina that created larger and a wider range of harvest gap sizes (0.13, 0.26, and 0.50 ha) revealed no difference in the abundance of insect herbivores (Ulyshen et al 2005) or carabid predators (Ulyshen et al 2006). Third, the living permanent reserve trees that were distributed throughout the harvest gaps (6-21% of starting stand basal area) in this study may have moderated the influence of the canopy openings.…”

Seasonal diets of insectivorous birds using canopy gaps in a bottomland forest

“…Bird abundance did not differ among gaps sizes or years (Bowen et al 2007). Although bird and arthropod abundance varied among sampling stations (Ulyshen et al 2004, Ulyshen et al 2005, Bowen et al 2007), stations were sufficiently close that birds may have consumed a prey item at one location (gap, edge, or forest) and then been captured at another location before the item passed from the crop. Therefore, data were averaged between years, among gap sizes, and among sampling locations (gap, edge, and forest).…”

“…Natural gaps (Willson et al 1982, Martin and Karr 1986) and group‐selection harvest gaps (Kilgo et al 1999, Moorman and Guynn 2001) contain greater numbers of birds than surrounding forest. Arthropod populations are also affected by forest‐canopy gaps and earlier stages of gap succession may support greater arthropod abundance than older forest‐canopy gaps (Ulyshen et al 2004, 2005, Ulyshen 2005). Flying arthropods may be more abundant in gap habitats than surrounding forest, whereas other groups, such as ground‐dwelling arthropods, are less abundant in gap habitat (Greenberg and Forrest 2003, Ulyshen 2005).…”