Lichen and bryophyte communities differed between managed second-growth and unmanaged old-growth grand fir forests in northwestern Montana in all three strata examined: lower canopy, trunk, and ground. Old-growth forests had larger trees, greater structural diversity, greater volumes of coarse woody debris, fewer species of vascular plants, more species of trunk epiphytes, higher β diversity, and higher γ diversity than second-growth forests. Although pendent fruticose lichens were common in both stand age classes, species of Alectoria were more abundant in old growth, while second growth was dominated by Bryoria spp. Nitrogen-fixing foliose lichens were more common in all strata of old growth, and Lobaria pulmonaria, a common N-fixing species in old growth, was absent in second growth. Cladonia spp. were more numerous in second-growth forests. Nearly all species of leafy liverworts were more common in old growth and typically occurred on rotting wood. Many of these liverworts were absent from second growth. Our results suggest that many species of lichens and bryophytes find optimum habitat in old-growth forests and that these species will become less common as silvicultural practices continue to convert old growth to younger aged forests. Key words: bryophytes, diversity, forests, lichens, Montana, old growth.

The true test of a habitat type classification and the manual that explains it can only be performed through actual use by a variety of field personnel. Following two seasons of field use, revising and updating this manual seemed warranted. This revised edition of "Forest Habitat Types of Northern Idaho: A Second Approximation" corrects errors in the first edition, clarifies information presented in text and tables, and adds new information such as a list of incidental communities. No major changes have been made to the classification or the keys in an attempt to maintain continuity with the first printing. A few minor changes in the canopy coverage value required for delineation of a habitat type phase have been introduced. We hope these changes are beneficial to understanding of all users.Appendix I is new and contains a list of incidental and rare habitat types and plant communities that may be encountered in northern Idaho. Recognition of many of these was included in the first edition, referencing the reader to classification publications for adjoining areas where the type is more fully described. The new list contains additional communities that may later be incorporated into habitat type descriptions. Before this can be done, additional field sampling, data anaylsis, and correlation with data from adjoining area classifications are needed.Appendix J contains map locations for important habitat types and phases of sampled stands. Map locations do not include all possible locations where a particular habitat type or phase may occur in northern Idaho.

Fire plays a large role in structuring sagebrush ecosystems; however, we have little knowledge of how vegetation changes with time as succession proceeds from immediate postfire to mature stands. We sampled at 38 sites in southwest Montana dominated by 3 subspecies of big sagebrush (Artemisia tridentata Nutt.). At each site we subjectively located 1 sample plot representing the burned area and an unburned macroplot in similar, adjacent, unburned vegetation. Canopy cover of sagebrush was estimated, and plants were counted in 10 microplots. Age and height of randomly chosen sagebrush plants in each size class were determined from 5 microplots. Average postfire time to full recovery of mountain big sagebrush (ssp. vasseyana [Rydb.] Beetle) canopy cover was 32 years, shorter for basin (ssp. tridentata) and much longer for Wyoming (ssp. wyomingensis Beetle & Young) big sagebrush. Height recovered at similar rates. There was no difference in canopy cover or height recovery between prescribed fires and wildfires in stands of mountain big sagebrush. We found no relationship between mountain big sagebrush canopy cover recovery and annual precipitation, heat load, or soil texture. Nearly all unburned sagebrush macroplots were uneven-aged, indicating that recruitment was not limited to immediate postfire conditions in any of the subspecies. Average canopy cover of three-tip sagebrush (A. tripartita Rydb.) did not increase following fire, and many three-tip sagebrush plants established from seed instead of sprouting. Our results suggest that the majority of presettlement mountain big sagebrush stands would have been in early to midseral condition in southwest Montana assuming a mean fire interval of 25 years. Only long firereturn intervals will allow stands dominated by Wyoming big sagebrush to remain on the landscape in our study area. We speculate that effects of site-specific factors conducive to sagebrush recovery are small compared to stochastic effects such as fire. Resumen El fuego jugó un gran papel en estructurar los ecosistemas de ''Sagebrush''; pero, tenemos poco conocimiento de cómo la vegetación cambia con el tiempo conforme la sucesión se desarrolla, desde el momento inmediato despue´s del fuego hasta las poblaciones maduras. Muestreamos 38 sitios en el suroeste de Montana dominados por tres subespecies de ''Big sagebrush'' (Artemisia tridentata Nutt.). En cada sitio, localizamos subjetivamente una parcela representando el área quemada y una macroparcela adyacente de vegetación similar sin quemar. La cobertura de copa del ''Sagebrush'' fue estimada y las plantas se contaron en 10 microparcelas. En cinco microparcelas, se determinó la edad y altura de plantas de ''Sagebrush'' elegidas aleatoriamente dentro de cada categoría de tamañ o. El tiempo promedio para la recuperación total de la copa del ''Mountain big sagebrush'' (ssp. vasseyana [Rydb.] Beetle) despue´s del fuego fue de 32 añ os, periodo más corto que para el ''Basin'' (ssp. tridentata) y mucho más largo que el del ''Wyoming (ssp. wyomingensis Beetle & ...

A land-classification system based upon potential natural vegetation is presented for the forests of eastern Idahowestern Wyoming. It is based on reconnaissance sampling of about 980 stands. A hierarchical taxonomic classification of forest sites was developed using the habitat type concept. A total of six climax series, 58 habitat types, and 24 additional phases of habitat types are defined. A diagnostic key is provided for field identification of the types based on indicator species used in development of the classification.In addition to site classification, descriptions of mature forest communities are provided with tables to portray the ecological distribution of all species. Potential productivity for timber, climatic characteristics, surface soil characteristics, and distribution maps are also provided for most types. Preliminary implications for natural resource management are provided, based on field observations and current information.

diversifolia c.t 11 Deschampsia cespitosal Potentilla diversifolia c.t 12 Hesperochloa kingiil Oxytropis campestris c.t 13 Turf Communities 13 Carex elynoides c.t 13 Carex scirpoideaJ Potentilla diversifolia c.t 14 Carex scirpoideal Geum rossii c.t 15 Dryas octopetala/ Polygonum viviparum c.t 16 Salix arctica/ Polygonum bistortoides c.t 16 Cushion Plant Communities 17 Carex rupestris/ Potentilla ovina c.t 17 Geum rossii/Arenaria obtusiloba c.t 22 Dryas octopetala/ Carex rupestris c.t 23 Slope Communities 23 Dry Slopes 24

The Centennial Sandhills of southwest Montana support a mosaic of shrub‐dominated vegetation in various stages of succession. The persistence of rare plants and plant communities depends on the presence of both early and late seral vegetation. Disturbances by fire, grazing, and burrowing are important processes opposing plant succession and influencing vegetation dynamics. We sampled vegetation in wind erosion (blowout), deposition, and stabilized sites on upper and lower slopes. Canonical correspondence analysis was employed to describe vegetation changes that occur during succession as soil organic matter and plant canopy cover increase and bare soil decreases. We used information on the effects of fire, ungulate grazing, and pocket gopher ( Thomomys talpoides) burrowing, and our empirically derived successional sequence, to develop a model of sandhills vegetation dynamics operating at local and regional scales. The model suggests that fire followed by intense ungulate grazing may be the only way to restore early seral vegetation to areas of low topographic relief. In areas of high topographic relief, restoring presettlement fire frequency should be adequate to maintain pocket gopher habitat and thus a high proportion of early seral vegetation. These hypotheses should be tested through a process of adaptive management aimed at sustaining a mosaic of early and late seral vegetation capable of supporting the full spectrum of native species.

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This report is dedicated to the memory of our esteemed colleague, Jim Reichel, who had initiated a biological inventory within the study area at the time of his tragic passing. The expertise and interest of U.S. Fish and Wildlife Service staff was integral to this project, which greatly benefited by the coordination and expertise of Mike Rabenberg. It also benefited from discussions and help of the entire Medicine Lake Office. The access permission and kindness of landowners and leasees contacted in this study are acknowledged with gratitude. Special thanks are also extended to all who provided information on the plant life of Sheridan County, or the county in general, including Mike Rabenberg (USFWS), Aldon Joyes, Doug Smith, Cherryl Wagner, Ted Nordhagen, Monica Friedrich (NRCS) and Terry Angvick (Extension Service). Characteristic plant associations of Sheridan County Appendix G. Range sites, ecological units, and plant associations of Sheridan County Appendix H. Summary table of Sheridan County plant species of special concern and watch species Appendix I. Sheridan County plant species of special concern and watch species Appendix J. Flora of Sheridan County Scientific and common names of plant associations Global Rank State Rank # of Sample Plots Big Muddy Medicine Lake Missouri Coteau Other