Document Type


Publication Date



The Shawangunk Ridge in the lower mid-Hudson Valley extends from the vicinity of Rosendale through New Jersey, Pennsylvania, Maryland and Virginia. Within the first thirty miles can be found five “sky lakes”: Mohonk, Minnewaska, Awosting, Mud Pond and Maratanza. Since these lakes occur on the top of the ridge they have no drainage basin. Here we report on the pH and other abiotic factors that impact the aquatic fauna of the Lily Pond (pH 6.58), a small, shallow body of water with a diverse faunal community on the grounds of Mohonk Mountain House. The pH of Mohonk Lake is 7 near the surface. Lake Minnewaska’s pH increased from 4 to 6 in the last twenty years. The pH of the other three sky lakes (pH=4) may be influenced by acid seeps, reactivation of faults permitting acidic water to migrate into the lakes, or a decrease in the buffering capacity of the underlying Martinsburg Formation. Thirteen taxa of aquatic insects inhabit the Lily Pond along with three invertebrate (Hirudinea, Isopoda, Arachnida) and six vertebrate taxa with a diversity index of 17.45. One of the most abundantly represented insect groups found in the Lily Pond, the Notonectidae, have been observed to prefer environments between a pH of 6 and 7.1, possibly precluding their presence from the more acidic sky lakes. A similar preference is supposed in other species.

Publisher's Statement

© 2014 The Geological Society of America. Reprinted with the permission of the publisher for noncommercial use. Please see the work itself for other copyright information. The original material can be found here.



To view the content in your browser, please download Adobe Reader or, alternately,
you may Download the file to your hard drive.

NOTE: The latest versions of Adobe Reader do not support viewing PDF files within Firefox on Mac OS and if you are using a modern (Intel) Mac, there is no official plugin for viewing PDF files within the browser window.