© The Nature Conservancy View/Download: Please click on the link(s) below and you will be given the choice of opening or saving to disk. JPG Download (JPG, 1.4 MB, Created January 01, 1999)

Rocky summits are a distinctive characteristic of the Northern Appalachian region which boasts over 100,000 examples of mountain peaks, bony ridges and stony hilltops. Some are dramatic features like the crest of Mt Katadin in Maine the point of first light in the eastern US - others are simply hilltops in an otherwise flat plain. Concentrated along the backbone of ancient mountains, these well loved places are favorite haunts of ravens, buteos and naturalists availing themselves of the unique vantage point to contemplate the landscape.

Summits form where hard bedrock resists weathering. Thus, biodiversity differences among summits correlate strongly with bedrock types additionally influenced by elevation and climate. High elevation summits, composed of granitic rock or resistant quartsites, sport thin acidic soils, bouldery outcrops, sparse, stunted trees, and a distinct flora. Low elevation summits typically exhibit open-canopy woodlands and tend to be dry, thin soiled and fire-prone. Pines (jack, pitch, red or white) show a preference for these low rocky hilltops.

Overall, summits cover 3% of the ecoregion (2,758,928 acres), but 75% of them are smaller than 30 acres in size and the average summit is 26 acres (+- 55 acres). At high elevations summits aggregate and fuse into large contiguous features defining our important mountain ranges (Figure 1). The Gaspe, Adirondacks and Green/White Mountain subregions contain the largest summits of the region (28 of them over 1000 acres) including the 78 summits higher than 4000 feet that exhibit true alpine conditions.

Results

Our goal was to locate a minimum of 20 exemplary occurrences per 22 bedrock/elevation combinations. Our results identified 1,938 critical occurrences, four times more than we needed to meet our total goal (Table 4). With small exceptions for shale and mid elevation calcareous summits we met our adequacy goals for identifying sites within each combination as well, thus, the portfolio is fully sufficient with respect to summits.

Defacto Candidate and Supporting Occurrences

In addition to the critical occurrences, this analysis encompassed a large number of less notable or poorly surveyed summits that did not meet our screening criteria for being a critical feature. We accounted for their potential contributions to biodiversity by sorting them into two categories and totaling the amounts of each.

 Candidate occurrence: A feature that met the criteria for size and landscape context but for which we had no verification or corroboration as to their condition and biodiversity contribution. These may be added to the portfolio after ground verification and are a logical place to focus inventory efforts.

 Supporting occurrence: A feature that did not meet the criteria for size and landscape context but may play a supporting role in supplementing the critical sites.

Many of the candidate and supporting occurrences already occur on protected reserves and thus are part of the defacto conservation picture for the region. Because conserved examples of these occurrences may serve to bolster biodiversity protection we included them for context in some of our analyses. However, candidate and supporting occurrences were not counted as contributing to the portfolio goals.

Summary:

Of the 104 thousand summits in the ecoregion, our portfolio highlights 3 percent that are the most critical to biodiversity conservation of summit communities and species. This important subset, found in 393 key sites, is well distributed across bedrock and elevation gradients and is 35% unprotected. About 65% (175K acres) of the summit portfolio remains to be protected. Particularly urgent are low elevation and sedimentary summits