Surveys & Monitoring for the Hiawatha National Forest Vernal Pools
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Surveys and Monitoring for the Hiawatha National Forest – Vernal Pools: FY2015 Report Prepared by: Yu Man Lee Michigan Natural Features Inventory P.O. Box 13036, Lansing, MI 48901-3036 For: Hiawatha National Forest Grant/Agreement No. 14-PA-11091000-020 February 25, 2016 Report Number 2016-06 Michigan Natural Features Inventory (MNFI) is a program of Michigan State University Extension in partnership with the Michigan Department of Natural Resources. Michigan Natural Features Inventory is Michigan’s natural heritage program, and a member program of NatureServe and the Natural Heritage Network. Funding for this project was provided by the U.S. Forest Service, Hiawatha National Forest, and Michigan Natural Features Inventory. The statements, findings, conclusions, and recommendations provided in this report are those of the Michigan Natural Features Inventory and Michigan State University (MSU) and do not necessarily reflect the views of the U.S. Forest Service or Hiawatha National Forest. Suggested Report Citation: Lee, Y. 2016. Surveys and Monitoring for the Hiawatha National Forest – Vernal Pools: FY2015 Report. Michigan Natural Features Inventory Report No. 2016-06, Lansing, MI. 85 pp. Cover Photograph: Center photo - Vernal pool, Hiawatha National Forest, Alger County, MI. Photo by Yu Man Lee, MNFI. Copyright 2016 Michigan State University Board of Trustees. Michigan State University Extension programs and materials are open to all without regard to race, color, national origin, gender, religion, age, disability, political beliefs, sexual orientations, marital status, or family status. EXECUTIVE SUMMARY Vernal pools are important to the biodiversity and health of Michigan’s forests. Vernal pools are small, temporary pools of water that form in shallow depressions primarily in forested areas throughout Michigan. Despite their small size and temporary nature, vernal pools can be incredibly diverse and productive ecosystems. Vernal pools provide important habitat for many plants and animals. Because vernal pools lack predatory fish populations, these wetlands provide critical breeding habitats for a host of forest-dwelling amphibians and invertebrates, including some species that are specialized for life in vernal pools and depend on these unique habitats for their survival. Vernal pools contribute other important ecosystem services including nutrient cycling, water storage and infiltration, groundwater recharge, and flood control. Due to increased awareness of the ecological significance of vernal pools, there has been growing interest in identifying, mapping, monitoring, and protecting these small but valuable wetlands in Michigan. Information on the status, distribution, and ecology of vernal pools is critical for developing and implementing appropriate management of these wetlands. The Hiawatha National Forest (HNF) is interested in obtaining this information regarding vernal pools within the Forest. To address this information need, the Hiawatha National Forest contracted with the Michigan Natural Features Inventory (MNFI) in 2015 to initiate a targeted effort to identify and map vernal pools within the Forest. Information on the locations and basic ecological characteristics of vernal pools were compiled as part of this project, and were provided to the HNF and added to a statewide spatial database of vernal pools in Michigan. This project included efforts to evaluate the effectiveness of aerial photograph interpretation for identifying and mapping vernal pools remotely. A total of 419 potential vernal pools were identified and mapped within the project’s study areas using aerial photograph interpretation. The project focused on the three project areas within the Hiawatha National Forest, the Plumb-Bruno, Raco, and Eckerman project areas (hereafter referred to as the Plumb-Bruno and the Raco-Eckerman Project Areas). These project areas are located in Alger, Chippewa, Delta, and Schoolcraft counties in the eastern Upper Peninsula (U.P.) of Michigan. The Plumb-Bruno Project Area is located on the west side of the Hiawatha National Forest in the Munising Ranger District. The Raco-Eckerman Project Area is located on the east side of the Hiawatha National Forest in the St. Ignace/Sault Ste Marie Ranger District. These forest lands are under active forest management. Total acreage of national forest lands that were included in the project areas and were reviewed for potential vernal pools using aerial photo interpretation was approximately 234,110 acres (94,741 ha). MNFI staff surveyed a total of 118 potential and new vernal pools in the field in 2015. Of these, 93 (22%) were potential vernal pools that had been identified and mapped from aerial photograph interpretation, and 25 were new or potential vernal pools identified in the field that had not been mapped during aerial photo interpretation. Of the 118 potential or new vernal pools surveyed, a total of 74 (63%) were verified as vernal pools. An additional 15 pools (13%) were identified as potential or likely vernal pools but their status is uncertain at this time, and additional data are needed for final designation of their status. Of the 29 potential pools that were verified as not being vernal pools, 16 (14%) were other types of wetlands, and 13 (11%) were areas that were dry and did not appear to hold water for extended periods of time. Surveys and Monitoring for the Hiawatha National Forest – Vernal Pools 2015, Page - i The overall accuracy rate for correctly identifying vernal pools from aerial photograph interpretation was moderate. Of the 93 potential vernal pools that were identified and mapped from aerial photos and surveyed in the field in 2015, 55 (59%) were verified as vernal pools in the field, and an additional 11 (12%) were identified as potential or likely vernal pools that need additional information to confirm their status. Combining the verified and potential/likely vernal pools would result in a total of 66 vernal pools identified in the field, and an overall vernal pool mapping accuracy rate of 71% for aerial photo interpretation across both study areas. The vernal pool accuracy rate varied between the two main project areas, with the Plumb-Bruno Project Area having an accuracy rate of 47% (22 verified vernal pools of 47 potential vernal pools) and the Raco-Eckerman Project Area having an accuracy rate of 72% (33 of 46). Commission error was moderate. A total of 28 (30%) potential vernal pools identified from air photos was surveyed and verified as not being vernal pools in the field. This also varied by project area, with the Plumb-Bruno Project Area having a commission error rate of 51% (24 of 47) and the Raco-Eckerman Project Area having a commission error rate of 9%. These accuracy and commission error rates are similar to and a little higher than results from previous vernal pool mapping efforts in the western U.P. Vernal pool indicator species were documented in 14 (37%) of 38 vernal pools that were surveyed in the Plumb-Bruno Project Area in the spring and early summer of 2015. These include observations of fairy shrimp (only in one pool), wood frog tadpoles, blue-spotted salamander egg masses and larvae, and spotted salamander egg masses and larvae. At least 18 other invertebrate taxa and five additional amphibian and reptile species associated with vernal pools also were documented in 2015. Potential exists for vernal pool indicator species and other amphibians, reptiles, and invertebrates to occur in the vernal pools in the two project areas. While mapping potential vernal pools using aerial photo interpretation can be time consuming and was only moderately accurate across the two project areas (and across the UP in general), aerial photo interpretation is currently still the most effective method we have for identifying and mapping vernal pools remotely. The accuracy rate was a little higher and more promising for one of the project areas, suggesting that the availability and use of more recent and higher resolution leaf-off, color-infrared aerial imagery can increase vernal pool mapping accuracy rates. We were able to identify and map a fairly large number of potential vernal pools across an extensive area over a relatively short period of time (i.e., ~5-7 days). While not all of these represent actual vernal pools on the ground, having this information has allowed us to conduct targeted field surveys which have resulted in identifying a total of 74 active vernal pools on the ground. These represent the first group of vernal pools identified and mapped in the eastern U.P. that has been entered into the statewide vernal pool database. Results from this project will inform management and protection of vernal pools, and provide the foundation for future vernal pool research and monitoring efforts in the HNF. This information will assist the HNF with forest planning and management efforts, and help facilitate sustainable forest management practices, ensuring the long-term productivity and health of Michigan’s forest ecosystems. This project also complements and builds upon recent vernal pool mapping and assessment efforts in the Upper Peninsula and statewide. This additional information will help us develop an effective and efficient approach for identifying and mapping vernal pools, and enhance our understanding of their distribution and ecology in Michigan and how to effectively manage and protect them. Surveys and Monitoring for the Hiawatha National Forest – Vernal Pools 2015, Page - ii TABLE OF CONTENTS INTRODUCTION ...............................................................................................................1