Landscape Ecosystems of the Fleming Creek Valley, University of Michigan’s Matthaei Botanical Gardens Report submitted in completion of research conducted for the Sam Graham’s Trees Project By Alan J. Tepley March 9, 2001 ACKNOWLEDGEMENTS This research was made possible by funding from the Graham Foundation. This research was conducted to provide a sound ecological basis for the grove locations for an interpretive educational trail to honor Dr. Samuel A. Graham, a former professor at the University of Michigan’s School of Natural Resources and Environment. Many individuals have contributed greatly to the success of this research. First, I would like to thank Dr. Burton V. Barnes for his guidance and support, and for his review of drafts of the report. I also would like to thank Dr. David Michener and Dr. Brian Klatt for their advice, encouragement, and for reviewing a draft of the report. Dr. Sylvia Taylor and the rest of the staff at the Matthaei Botanical Gardens also provided encouragement due to their interest in the research. The development of GIS maps would not have been possible without the help of the staff at the Environmental and Spatial Analysis (ESA) lab at the University of Michigan’s School of Natural Resources and Environment. Ecosystems of the Fleming Creek Valley Page-i Ecosystems of the Fleming Creek Valley Page-ii Landscape Ecosystems of the Fleming Creek Valley, University of Michigan’s Matthaei Botanical Gardens ABSTRACT: A landscape ecosystem approach was applied to a 50-ha portion of the Fleming Creek valley at the University of Michigan’s Matthaei Botanical Gardens, Washtenaw County, Michigan. Using an ecological, multifactor approach integrating physiography, hydrology, soil, and vegetation, ecosystems were classified, described, and mapped at three hierarchical levels (Physiographic System, Landform-Level Ecosystem, and Landscape Ecosystem Type). One Physiographic System (Outwash Plain), 2 Landform-Level Ecosystems (Terrace and River Floodplain), and 16 Landscape Ecosystem types were identified, classified, and mapped. Although Fleming Creek is a relatively small stream, the physiographic shape of its valley and the associated pattern of ecosystems are similar to that of many major river valleys. Despite its small area, the Botanical Gardens exhibits a remarkable diversity of ecosystems. The terrace is composed of two ecosystem types, a dry-mesic ecosystem, and a wet depression. The floodplain contains 14 ecosystems, which were ordered into 4 groups; first bottom, second bottom, groundwater seepage, and miscellaneous floodplain features. The ecosystem types of the first bottom include levee, first bottom flat, backswamp, depression, meander-scar marsh, and a wet- mesic ecosystem adjacent to the stream and below upland features. The second bottom contains a moderately well drained ecosystem type on loamy soil, a somewhat poorly drained ecosystem on clay loam to clay soil, and a groundwater seepage on muck. Most of the west side of the floodplain consists of a groundwater seepage that gently slopes from the levee to the terrace. Miscellaneous floodplain features include a deposit of marl overlaid by a thin layer of mineral soil, a crevasse filling, a ridge that remains after a late 19th century or early 20th century excavation, and risers, or steep slopes that separate bottoms or terraces. Within two ecosystem types, the first bottom flat and the groundwater seepage, inclusions, or areas of relatively homogeneous soil and hydrologic conditions, were identified to aid in the interpretation of fine scale variability. Because the Botanical Gardens contains many ecosystem types within a small area, and the pattern of ecosystems represents that of many river valleys, it has high potential for education about the landscape ecosystems of river valleys and their function within the broader landscape. Ecosystems of the Fleming Creek Valley Page-iii Ecosystems of the Fleming Creek Valley Page-iv Table of Contents Page Acknowledgements ................................................................................................................... i Abstract ..................................................................................................................................... iii List of Tables ............................................................................................................................. vi List of Figures ........................................................................................................................... vii List of Appendices ..................................................................................................................... ix Introduction ............................................................................................................................... 1 Objectives ......................................................................................................................... 5 Hierarchical Organization of Ecosystem .......................................................................... 6 Methods ..................................................................................................................................... 9 Study Area ................................................................................................................................. 12 Glacial History .................................................................................................................. 12 Postglacial Influences on Fleming Creek Valley Geomorphology ................................... 17 Results and Discussion.............................................................................................................. 19 Overview of the Classification ......................................................................................... 19 Inclusions within Landscape Ecosystem Types ................................................................ 27 Physiographic Pattern and the Correspondence of Species.............................................. 30 River Valley............................................................................................................. 35 River Floodplain..................................................................................................... 37 General Discussion ................................................................................................................... 42 Levels of Classification .................................................................................................... 42 Presettlement Vegetation .................................................................................................. 43 Michigan Natural Features Inventory Community Types ...................................... 46 Similarities to Other River Valleys................................................................................... 48 Terrace .................................................................................................................... 48 Levee ....................................................................................................................... 49 First Bottom ............................................................................................................ 49 Second Bottom ........................................................................................................ 53 Alterations of the Landscape ............................................................................................ 54 Ecosystem Diversity ......................................................................................................... 55 Flood Control and the Lack of Fire .................................................................................. 56 Death of American elm and Tamarack ............................................................................. 61 Summary and Conclusions ....................................................................................................... 65 Ecosystems of the Fleming Creek Valley Page-v List of Tables Page Table 1. Classification of the landscape ecosystems and their corresponding 20 presettlement cover types within a segment of the Fleming Creek Valley, University of Michigan’s Matthaei Botanical Gardens. Washtenaw Co., Michigan Table 2. Community composition of the first bottom flat. University of 58 Michigan's Matthaei Botanical Gardens. Washtenaw Co., Michigan. Table 3. Correspondence of overstory and understory vegetation to ecosystem 60 type along a moisture gradient in the ecosystems of the second bottom. University of Michigan's Matthaei Botanical Gardens. Washtenaw Co., Michigan. Table 4. Present community structure in ecosystems formerly occupied by 64 American elm and eastern larch. University of Michigan's Matthaei Botanical Gardens. Washtenaw Co., Michigan. Ecosystems of the Fleming Creek Valley Page-vi List of Figures Page Figure 1. Map of the regional landscape ecosystems of Lower Michigan (a) 7 (Albert et al. 1986). Roman numerals indicate Regions, divided by a thick dark line. Within each region, Districts and Subdistricts are indicated by thinner lines, as well as integers and decimals, respectively. The location of the University of Michigan’s Matthaei Botanical Gardens is indicated by a star. Hierarchical organization of regional and local landscape ecosystems (b), with a generalized classification of the ecosystems of the Botanical Gardens superimposed on the progression from regional to local ecosystems.