Biological Survey of a Prairie Landscape in Montanas Glaciated Plains Final Report Prepared for: Bureau of Land Management Prepared by: Stephen V. Cooper, Catherine Jean and Paul Hendricks December, 2001 Biological Survey of a Prairie Landscape in Montanas Glaciated Plains Final Report 2001 Montana Natural Heritage Program Montana State Library P.O. Box 201800 Helena, Montana 59620-1800 (406) 444-3009 BLM Agreement number 1422E930A960015 Task Order # 25 This document should be cited as: Cooper, S. V., C. Jean and P. Hendricks. 2001. Biological Survey of a Prairie Landscape in Montanas Glaciated Plains. Report to the Bureau of Land Management. Montana Natural Heritage Pro- gram, Helena. 24 pp. plus appendices. Executive Summary Throughout much of the Great Plains, grasslands limited number of Black-tailed Prairie Dog have been converted to agricultural production colonies that provide breeding sites for Burrow- and as a result, tall-grass prairie has been ing Owls. Swift Fox now reoccupies some reduced to mere fragments. While more intact, portions of the landscape following releases the loss of mid - and short- grass prairie has lead during the last decade in Canada. Great Plains to a significant reduction of prairie habitat Toad and Northern Leopard Frog, in decline important for grassland obligate species. During elsewhere, still occupy some wetlands and the last few decades, grassland nesting birds permanent streams. Additional surveys will have shown consistently steeper population likely reveal the presence of other vertebrate declines over a wider geographic area than any species, especially amphibians, reptiles, and other group of North American bird species small mammals, of conservation concern in (Knopf 1994), and this alarming trend has been Montana. linked to loss of grassland habitat. However, in Some obligate grassland birds are sensitive to the Bitter Creek Frenchman Creek portion of habitat conversion on landscape scales and favor Montanas Northwestern Glaciated Plains larger grassland patches. Their larger numbers Section, large intact prairie communities can still in the Bitter Creek area, relative to other prairie be found across a diverse landscape. This regions in Montana, reflect this preference. prairie landscape is the largest remaining intact Thus, the extensive and contiguous native prairie grassland north of the Highline in Montana and rangelands of the Bitter Creek Frenchman even more significantly, stands out as one of the Creek study area are important for maintaining most extensive naturally functioning glaciated diverse communities and large viable popula- plains grassland in North America. This prairie tions of native grassland-dependent birds and landscape, a remnant of what once existed more other animals. widely in Montana, has important conservation value for grassland-obligate species that are Within the greater Bitter Creek Frenchman elsewhere threatened by habitat loss. Creek area we identified seven landscape sites, each with a distinctive suite of characteristics, In 1999 and 2000, the Montana Natural Heritage that stand out as exceptional examples of Program, in cooperation with the Bureau of glaciated plains. The extent of the intact prairie Land Management, conducted a biological and the quality of these landscapes, qualify this inventory and assessment of the Bitter Creek part of Montana as an outstanding Great Plains Frenchman Creek area. The primary objective mid-grass prairie landscape. One of the most was to document the distribution and biological outstanding areas, the Dry Fork Creek land- significance of this native prairie landscapes scape, harbors an extensive, intact tract of vegetation communities and to assess the status northern porcupine grass thickspike wheat- of plant and animal species of concern and other grass, a rare mid-grass prairie association. This grassland obligate species that occur there. is one of the best if not the best stands of its The variable topography and vegetation in the type documented in all of the US Great Plains, Bitter Creek Frenchman Creek area support a making Dry Fork Creek an area of national diverse native vertebrate fauna typical of the significance. This important grassland domi- northern Great Plains. A complete suite of nates a large block of school trust lands managed grassland-obligate birds is still present, including by the Montana Department of Natural Resource Spragues Pipit and Bairds Sparrow both Conservation and leased for grazing. The state Montana Species of Concern. These and other and private lessee have maintained this notable bird species are present because the grasslands grassland through good stewardship practices. in this region provide a mosaic of structure (in Livestock grazing is highly compatible with both density and height) and food resources natural ecological processes that maintain these where they can settle and nest successfully. This grasslands, whereas plowing the grassland for landscape is also important for other vertebrate agricultural production would result in a perma- species of conservation concern, including a nent loss of this important grassland. i Acknowledgements Thanks to David Waller, Bureau of Land Man- Whitney Weber (MTNHP) did likewise for the agement (BLM) wildlife biologist at the shaded relief map. Cedron, Martin Miller and Glasgow and Malta Field Offices for providing Terrie Kenney (MTNHP) processed plant key information. We also appreciate Steve association records, Terrie entered information Klessens and John Fahlgren for sharing their and photographic images into program databases intimate knowledge of the vegetation resources and Ryan Rausher (FWP) helped make the within the study area. climate diagram. Mike Roedel (former MTNHP Zoology Program Manager) conducted the initial We appreciate Brian Martin, Montana Field year of zoological field sampling. Bob Bramblett Office of The Nature Conservancy, for originally generously provided information on native fish piquing our interest in the study area and con- populations of Rock Creek. The report benefited tinuing to be a source of information, he and Sue significantly from our discussions with botanist Crispin provided insightful editorial comment. Bonnie Heidel (MTNHP) regarding the ecology Mr. Lynn Cornwell of Glasgow, MT, whose and distribution of prairie communities. Thanks extensive ranching operations are embedded to Joy Lewis (MTNHP) for her editing and squarely within the study area, graciously production help. provided access to his private holdings and Though this report has profited from the support contributed a stockmans perspective and and contributions of many people, any errors of background information regarding northern commission or omission rest with the authors. Valley County. This project was supported by a challenge cost- Cedron Jones, Montana Natural Heritage share agreement between the Bureau of Land Program (MTNHP) designed and produced the Management and the Montana Natural Heritage study area map and Duane Lund, Natural Program (BLM Agreement Number Resource Information Systems (NRIS) and 1422E930A960015, Task Order # 25). ii TABLE OF CONTENTS Executive Summary .................................................................................................................................... i Acknowledgements ................................................................................................................................... ii Table of Contents......................................................................................................................................iii Introduction ............................................................................................................................................... 1 Study Area ................................................................................................................................................. 2 LOCATION .............................................................................................................................................. 2 GEOLOGY AND SOILS .............................................................................................................................. 2 CLIMATE ................................................................................................................................................ 4 VEGETATION .......................................................................................................................................... 5 Methods ..................................................................................................................................................... 6 INVENTORY ............................................................................................................................................ 6 DATA MANAGEMENT ............................................................................................................................... 8 VEGETATION A NALYSIS ........................................................................................................................... 8 Results ....................................................................................................................................................... 9 VEGETATION .......................................................................................................................................... 9 SHRUBLANDS ......................................................................................................................................