Rare Lepidoptera and Shrubland Birds: Their Presence, Distribution and Habitat Preferences in NH
Updated: Dec 22, 2020
Full title: Rare Lepidoptera and Shrubland Birds: Their Presence, Distribution and Habitat Preferences on the Ossipee Pine Barrens Preserve in Carroll County, New Hampshire – A 2002 field survey
Author: Jon Kart, UVM
Abstract: The Ossipee Pine Barrens, a globally rare natural community type occurring in east central New Hampshire, once covered an estimated 2,800 hectares (ha). Habitat conversion has reduced the barrens to approximately 800 ha and habitat fragmentation and fire suppression have significantly degraded what remains.
Despite the significant ecological degradation and the continued threat of development, the Ossipee Pine Barrens is the last viable Northern New England Pitch Pine-Scrub Oak Barrens in New Hampshire and one of the best remaining in the Northeast. Ossipee is also home to more than a dozen rare Lepidoptera and several species of shrubland birds whose populations are in steep decline.
The Nature Conservancy (TNC) owns 365 ha within the Ossipee Pine Barrens (Map 1). Their goal is to preserve the Ossipee Pine Barrens and its associated species as an exemplary pitch pine-scrub oak barrens community. To help achieve this goal, TNC has commissioned this research project to assess occurrence, distributions and habitat preferences of rare moths and butterflies (Order Lepidoptera) and declining shrubland birds native to the barrens. To accomplish this:
Lepidoptera were collected and recorded with black lights and bait traps regularly between May and September, 2003.
Eastern towhee and brown thrasher behavior were mapped between June and August, 2003.
Extensive efforts were made to compile, review, and synthesize existing information on the biology and ecology of these taxa and their interactions with pitch pine-scrub oak barrens.
More than 2500 Lepidoptera specimens were recorded comprising 246 species in 12 families (Appendix C), including six of the 15 rare species (tables 1 and 4, Figure 2). Of the nine rare species not collected in 2002, all but two were not active during the sample period. The six rare species recorded were:
Species Rarity Rank*
Glena cognataria G4G5 S3
Itame sp. 1 G3Q S1S2
Apharetra dentata G4 S2
Xestia elimata, G5 S3S4
Zale obliqua G5 S2
Zanclognatha martha G4 S1
*See Appendix A for a discussion of New Hampshire Heritage Bureau’s Rarity Ranking.
Of these six species, five were found in more than one location in the barrens. The widespread distribution of these species will allow more flexibility as managers plan restoration activities (Goldstein 1997, Thomas 2000). An additional 47 Lepidopteran species of conservation interest (Appendix E) were also collected, 22 of which were also found at more than one sample site (Appendix E).
Eastern towhee, though found throughout the barrens, showed a preference for open-canopied scrub oak thicket with less than 10% forest canopy cover. No brown thrasher pairs were found in the study plots, though they were seen elsewhere in the barrens. Anecdotal observations indicate that thrasher prefer less dense ground cover than the towhee, with some access to thickets and pitch pine forest edges.
Though not part of the bird mapping study, four other bird species of conservation interest were regularly seen at Ossipee: common nighthawk (Chordeiles minor), whip-poor-will (Caprimulgus vociferus), prairie warbler (Dendroica discolor) and vesper sparrow (Pooecetes gramineus). Observations of the nighthawk population in particular indicates that it may be the most dense population in the state.
This research should help preserve managers to conserve more effectively Ossipee’s rare Lepidoptera and shrubland birds as well as the ecosystem as a whole. This research dovetails with a companion study by Dacey (2003) on the vegetation of the Ossipee Pine Barrens Preserve that was also commissioned by TNC.