Article

The application of insular biogeographic theory to the conservation of large mammals in the northern Rocky Mountains

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Abstract

The presence of 10 species of large mammals in 24 mountain ranges of central Montana was investigated. The occurrence of these species in relation to land area during historical times was found to be similar to the continental distribution described by biogeographic theory (z = 0·15). Habitat diversity was related to area and the topographic relief and, in turn, the presence of the mammal species was correlated with the number of habitat types as well as area. The insularity of the mammal populations of the larger land units increased (from z = 0·15 to z = 0·39) as human economic development occurred. Large area and increased topographic relief tended to protect species from impact extinction. Wildlife conservation programmes restored populations to many areas, having their greatest impact upon units ranging in size from 130 to 5700 km2.

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... Ecologists have approached the study of habitat fragmentation for the past 25 years largely within the framework of two key theoretical developments in community and population ecology: the theory of island biogeography Wilson, 1963, 1967) and metapopulation dynamics (Levins, 1969). In the context of habitat fragmentation, the theory of island biogeography has guided study focused primarily on the influences of habitat fragment size and isolation on species composition (Forman et al., 1976;Picton, 1979;Newmark, 1986;Blake and Karr, 1987;Bierregaard et al., 1992;Robinson et al., 1992), while the metapopulation dynamics concept has focused attention on connectivity and interchange between spatially distributed populations (Fahrig and Merriam, 1985;Lankester et al., 1991;Hanski et al., 199.5). ...
... For example, a study of grassland bird communities showed that approximately 79% of the grassland bird species were present in a 1000 ha grassland fragment, while only 3 1% of the bird species occurred in IO-ha grassland fragments (Herkert, 1994). This habitat fragment species-area pattern has been documented in other habitats, as well, for mammals (Picton, 1979;Newmark, 1986;Vemer et al., 1986;Bennett, 1990;Verboom and Van Apeldoom, 1990;Cutler, 1991;Bierregaard et al., 1992), insects (Webb and Hopki!s, 1984;Powell and Powell, 1987;Klein, 1989;As, 19931, amphibians (Dodd, 1990;Laan and Verboom, 19901, and herbaceous plants (Simberloff and Gotelli, 1984;Webb and Vermaat, 1990). These results are consistent with patterns predicted from island biogeographic theory relating island size to species richness (MacArthur and Wilson, 1967). ...
... A factor shown to be partially responsible for the relationships found between species composition and fragment spatial characteristics is the degree of habitat heterogeneity within isolated fragments. Large fragments are more likely to contain a greater variety of soil types, greater topographic variation, greater microclimatic variation, and a greater number of habitat types than small fragments (Pickett and Thompson, 1978;Picton, 1979;Boecklen, 1986). Fragments of approximately equal size which are relatively heterogeneous tend to support a greater number and variety of species than those which are more homogeneous (Picton, 1979;Simberloff and Gotelli, 1984;Boecklen, 1986;Newmark, 1986;Freemark and Merriam, 1986;MacDonald and Johnson, 1995;Maehr and Cox, 1995). ...
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Habitat loss and isolation associated with land conversion for human activities constitute the most serious threat to the Earth's biological diversity. The study of habitat fragmentation provides an important link between the concepts and principles of landscape ecology and the practice of landscape architecture and planning. Here I review ecological literature to examine current understanding of the ecological consequences of habitat fragmentation, and briefly suggest ways in which the results of these studies may guide decision-making by landscape architects and planners. Two theoretical developments in ecology have informed studies of habitat fragmentation and have provided testable hypotheses for empirical studies: island biogeography theory and metapopulation dynamics. Ecologists have examined the influences of habitat fragment size, shape, degree of isolation, context, and habitat quality or heterogeneity on plant and animal population persistence, community composition, and ecosystem processes.
... The effects of park isolation and faunal collapse have been studied for mammals in Rocky Mountain parks (Picton 1979, Newmark 1986, Glenn and Nudds 1989. In western U.S. parks, extinctions were more numerous in smaller or older parks (Newmark 1987). ...
... Area, topographic diversity, and habitat diversity have been correlated with mammal species richness .in western North American parks (Picton 1979, Newmark 1986). Initial population size was also related to the extinction probability of a species (Newmark 1986). ...
Article
The equilibrium theory of island biogeography proposes that on an island of a given area, there exists an equilibrium number of species when the rates of immigration and local extinction of species are equal (MacArthur and Wilson 1967). This theory has been applied to park systems because parks may act as functional islands when surrounding unprotected land is cleared of natural vegetation. Alteration of these surrounding habitats isolates these parks and reduces the effective area, causing a decrease in the equilibrium number of species. In animal communities, this process is called faunal collapse (Soule et al. 1979).The effects of park isolation and faunal collapse have been studied for mammals in Rocky Mountain parks (Picton 1979, Newmark 1986, Glenn and Nudds 1989). In western U.S. parks, extinctions were more numerous in smaller or older parks (Newmark 1987). Area, topographic diversity, and habitat diversity have been correlated with mammal species richness in western North American parks (Picton 1979, Newmark 1986). Initial population size was also related to the extinction probability of a species (Newmark 1986). It has been proposed that all parks in a region are subject to similar factors influencing local extinctions, and therefore a similar suite of species should become locally extinct in all parks (Patterson and Atmar 1986, Patterson 1987). This means that a nested subset pattern is produced, where parks with low species richness contain mainly species already present in parks with high species richness. This pattern was not found for Canadian parks, where even small parks contained different species assemblages (Glenn 1990). The objectives of this three-year study are to: (i) identify mammal species that have become locally extinct in each of the Rocky Mountain National Parks; (ii) distinguish between hypotheses regarding the causes of these local extinctions in National Parks; (iii) determine if the same species become locally extinct in all parks; and (iv) identify potential sites for future protection of species prone to extinction.
... The theory of island biogeography has been extended to include continental areas. A biological island is an area of at least marginal habitat surrounded by areas of unacceptable quality (Picton 1979;Picton and Mackie 1980). Most nature reserves are natural landscape "islands" surrounded by expanses of culturally modified habitat (Pickett and Thompson 1978). ...
... There is substantial evidence that the probability of loss of rare species is related to reserve size and isolation, species natural history, and population size and isolation (White and Bratton 1980). Habitat diversity, in combination with size, has a significant effect on species richness (Picton 1979;Kitchener et al. 1982;Reed 1983;Freemark and Merriam 1986). Additionally, reserve shape determines effective protection and management (Schonewald-Cox and Bayless 1986). ...
Article
The U.S. Fish and Wildlife Service (USFWS) recognizes Tamaulipan brushland as a unique ecosystem that is found only in the Lower Rio Grande Valley (LRGV) of south Texas in the United States and northeastern Mexico. The LRGV is not really a valley but a delta, or a fertile plain, that slopes away from the Rio Grande (Johnston 1963; Rio Grande Valley Chamber of Commerce 1983; Lonard et al. 1988). The combination of climate, vegetation, and associated wildlife is unlike that in any other region of the United States. The vegetation is influenced by edaphic factors, and plant distribution can be correlated with geologic formations (Clover 1937). Characteristic vegetation of Tamaulipan brushland is dense and thorny. The most luxuriant brush is found on alluvial soil of the Rio Grande floodplain (Blair 1950), and large cedar elms (Ulmus crassifolla) dominate in some mesic areas. Vegetation in the xeric upland areas is mostly spiny shrubs and stunted trees (Clover 1937). A few characteristic plant species comprise the bulk of the brush vegetation. At present, some of the ubiquitous woody plant species are (Blair 1950): Texas ebony (Pithecello)- bium flexicaule); retama (Parkinsonia aculeata); granj eno (Celtis pallida); huisache (Acacia srnallii); prickly pear (Opuntia lindheimeri); and mesquite (Prosopis glaiidulosa) - although prevalence of one mesquite may be due to human land abuse (Archer et al. 1988).
... Our purpose is not to reexamine the SLOSS issue per se, but to discuss the assertion that effectively states that habitat fragmentation should be innocuous to most species, and therefore need not be a consideration in reserve design. This conclusion runs counter to the prevailing view that habitat fragmentation negatively affects population survival, and thus biological diversity, and therefore should be a prime consideration in conservation strategy (e.g., Janzen 1974;Picton 1979;Soule and Wilcox 1980;Lovejoy and Oren 1981;Whitcomb et al. 1981). In view of the increasing interest in the application of biological theory to conservation and the reliance on the scientific literature for guidance in conservation decisions, we feel that this contradiction warrants examination. ...
Article
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Discusses the assertion that effectively states that habitat fragmentation should be innocuous to most species, and therefore need not be a consideration in reserve design. This conclusion runs counter to the prevailing view that habitat fragmentation negatively affects population survival, and thus biological diversity, and therefore should be a prime consideration in conservation strategy. This apparent contradiction arises from 3 sources: 1) the 'single large or several small reserves will protect more species' is not equivalent to, or is at very best a special case of, the problem of habitat fragmentation; 2) the population model Simerloff and Abele (1982) (see 83L/2948) employ is inadequate because it ignores key factors affecting population survival; and 3) Simerloff and Abele's treatment does not consider how the disposition of one species may affect the survival of others, because it is limited to single-species population phenomena and ignores interspecific interactions or community-level phenomena.-from Authors
... Because there are no methods to determine the minimum areas of reserves with reference only to ecosystem properties (see Soulé & Simberloff 1986, Beier 1993, biologists have been forced to conduct viability analysis for a few "indicator" or "umbrella" species as an effi cient way to address the viability of the whole system (Soulé 1987, Noss 1991. These analyses, however, have focused on large vertebrates, which require large areas (e. g. Picton 1979, Freemark & Merriam 1986, Dodd 1990, Laurance 1990, Beier 1993, Lankester et al 1991, Newmark 1991, Opdam 1991, Herkert 1994, Brooks et al 1999, Chiarello 1999 but little is known about the effects of fragmentation on faunas of invertebrates (see Hopkins & Webb 1984, Klein 1989, Daily & Ehrlich 1995. ...
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Male orchid bees were attracted to chemical baits and collected in nine Atlantic Forest fragments in southeastern Brazil. Fragments differed in size and shape. Three additional sites were also sampled in a nearby large fragment. Three hypothetical core areas of each fragment were measured as the total area minus an area of 50, 100, and 200-m-wide perimeter. Abundance and richness were not correlated with either fragment size or ratio area/perimeter, but were positively correlated with the size of core areas. These results suggest that orchid bee conservation requires the preservation of the fragments with the largest possible core areas. Neither size nor shape alone (area/perimeter ratio) seemed to be good indicators of the value of a given fragment for sustaining diverse and abundant faunas of orchid bees.
... Yet, rumors of the death of the SLOSS debate were greatly exaggerated, for it continued beyond the mid-1980sbriefly mutating into the single-large-orplentifully-patchy (SLOPP) debate of Quinn and Hastings (1987) and Gilpin (1988) in the late 1980sright up to the present. Soulé and Simberloff (1986) suggested that the truly important remaining question was "the dynamics of species extinction after the reserves are set up and surrounded by habitat modified by human activities," as had Kushlan (1979), Picton (1979), and others nearly a decade earlier. Clearly, this statement implies that too much emphasis had been placed on area (the extinction side of island biogeography) and too little on isolation (the colonization side of island biogeography). ...
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A species–area relationship is simply the observation that the number of biological species found in a region is a positive function of the area in the region. Species–area relationships are depicted graphically as a bivariate plot of species richness on the ordinate and area on the abscissa, a species–area curve. Species–area relationships appear to be ubiquitous, which have been observed for a wide array of taxa ranging from diatoms to fish, insects, birds, vascular plants, and mammals and for geographical entities such as islands, political entities, woodland, grassland, and cropland habitat patches, lakes, river drainages, and artificial substrates from microscope slides to synthetic sponges and slates.
... Because they concern the manner in which diversity accumulates with area, SARs are at the heart of understanding the distribution of biological diversity in space. Ecologists have employed SARs to investigate community properties (Cain 1938), to estimate diversity (Plotkin et al. 2000b), to understand the loss of species caused by both habitat destruction (Harris 1984, Pimm and Askins 1995, Brooks et al. 1997, Harrison and Bruna 1999 and climate change (Thomas et al. 2004, Malcolm et al. 2006, and to design strategies for the conservation of biodiversity (Picton 1979, Shafer 1990). Additionally, attempts to develop synthetic theory in ecology have linked SARs to a number of key ecological patterns (Hanski andGyllenberg 1997, Harte et al. 1999). ...
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Species–area relationships (SARs) are a key tool for understanding patterns of species diversity. A framework for the interpretation of SARs and their prediction under different landscape configurations remains elusive, however. This article addresses one of these configurations: how species’ minimum-area requirements affect the shape of island or other isolate Species–area curves. We distinguish between two classes of SARs: sample-area curves, compiled entirely within larger contiguous areas, and isolate curves, compiled between isolated areas. We develop this conceptual and graphic model in order to illuminate landscape-scale diversity patterns, to discuss how various landscape and species characteristics affect outcomes, and to investigate the dynamics of local extinction under conditions of habitat fragmentation. Minimum-area effects on actual islands and other isolates predictably cause Species–area curves either to be sigmoid in arithmetic space or to be lowered for smaller areas. In order to illustrate the inherent shape of isolate curves, this study fits convex and sigmoid regression models to empirical isolate (island) data sets that cover the small scales expected to include inflection points.
... Identifying minimum sizes for protected areas is an important issue in conservation biology (Meffe and Carroll 1994 ). Although large reserves are clearly necessary for many ecosystem processes and components (e.g., interior-forest microclimate [Chen et al. 1995] and wide-ranging carnivores [Picton 1979, Newmark 1987), smaller forest remnants also may have high conservation value, especially in landscapes that are intensively managed for timber production. Investigators working in different forest ecosystems have found that small patches (2–9 ha) of intact forest may retain interior-forest vegetation (Ranney 1977, Levenson 1981, Kapos 1989, Matlack 1994 ) and that depthof-edge influence does not vary with patch size (Brothers and Spingarn 1992, Young and Merriam 1994, Burke and Nol 1998). ...
Article
Aggregated retention of overstory trees is now a standard component of timber harvest prescriptions on federal lands in the Pacific Northwest. Patches of remnant forest retained during harvest are thought to enhance the structural and biological diversity of managed forests, but the extent to which they maintain components of the original understory or promote recovery in adjacent harvest areas has not been tested. We examined short-term (1-and 2-yr) responses of understory plants to disturbance and creation of edges in structural retention harvest units at two sites in the western Cascade Range of Washington. Pre-and post-treatment abundance of vascular plants was measured in four (two at each site) 1-ha aggregates (patches of intact forest) and in surrounding harvest areas along sixteen 81 m long transects placed perpendicular to the edges of these aggregates. Two years after treatment, aggregates had gained an average of two forest species (vs. a loss of two in adjacent areas of harvest) and less than one early-seral species (vs. a gain of nine in adjacent areas of harvest). Aggregates supported populations of late-seral species that disappeared from or declined substantially in harvested areas. However, aggregates showed edge-related changes in plant abundance: one third of common understory herbs declined significantly in cover toward the edge, and changes in community composition were distinctly higher within 5 m of the edge than in the aggregate center. Early-seral species established infre-quently within the aggregates, and only within 10 m of the edge. Herbaceous species generally showed larger declines in abundance with proximity to edge than did shrubs, with declines becoming more prominent over time. Our results suggest that, over short time frames, forest aggregates of one or more hectares may play an important role in maintaining plant species richness and composition in forests managed for timber harvest. Assessing the longer term stability of forest aggregates and the degree to which they influence recovery in adjacent areas of harvest will require continued observation.
... Rosenberg and Raphael (1986) reported that gray foxes, ringtail cats, and northern flying squirrels were sensitive to forest fragmentation. Picton (1979) found that the presence of large mammals was correlated with the size of the mountain ranges where each species occurs. Mammal population can increase when minimum habitat size requirements are met. ...
Article
Southern Region, USDA Forest Service What are the history, status, and projected future of terrestrial wildlife habitat types and species in the South? 1 Key Findings • There are 132 terrestrial vertebrate species that are considered to be of conservation concern in the South by State Natural Heritage agencies. Of the species that warrant conservation focus, 3 percent are classed as critically imperiled, 3 percent as imperiled, and 6 percent as vulnerable. Eighty-six percent of terrestrial vertebrate species are designated as relatively secure. The remaining 2 percent are either known or presumed to be extinct, or have questionable status. • Species of conservation concern are dominated by amphibians and reptiles. Fifty-four amphibians, 40 reptiles, 20 birds, and 18 mammals are classed as imperiled. • Increasing population trends are reported for wild turkey, white-tailed deer, and black bear. Populations of northern bobwhite quail and gray, fox, and red squirrels have declined for several years. There have also been declines in mourning dove and American woodcock populations. Cottontail rabbit and ruffed grouse populations have demonstrated cyclical patterns. Among the migratory game birds, record harvests of ducks and geese have occurred in recent years. • Groups of nongame birds with more than 50 percent of their species showing significant declining trends include grassland-nesting birds (70 percent), ground-nesting birds (57 percent), and shrubland-nesting birds (53 percent).
... Of those available, biogeographic and evolutionary influences are particularly important and clear habitat associations are often lacking. For example, habitat size, a biogeographic feature, is most important to the distribution of big game (Picton 1979) and birds (Thompson 1978) in the northern Rocky Mountains, to mammals and birds of the Inter-mountain Region (Brown 1978), and to the birds of the eastern forest (Robbins 1979) and northern forestbog habitat (Anderson and Robbins 1981). There is, moreover, information from an evolutionary viewpoint that bird populations of the grassland-steppe habitat vary largely independently of one another; responses of birds to habitat characteristics differ at levels of local, regional or continental scales, and some species apparently occur independent of most habitat features (Weins and Rotenberry 1981). ...
Article
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This report is volume 1 of a two-volume ecological assessment of grassland ecosystems in the Southwestern United States. Broad-scale assessments are syntheses of current scientific knowledge, including a description of uncertainties and assumptions, to provide a characterization and comprehensive description of ecological, social, and economic components within an assessment area. Volume 1 of this assessment focuses on the ecology, types, conditions, and management practices of Southwestern grasslands. The second volume, due to be published in 2005, describes wildlife and fish species, their habitat requirements, and species-specific management concerns, in Southwestern grasslands. This assessment is regional in scale and pertains primarily to lands administered by the Southwestern Region of the USDA Forest Service (Arizona, New Mexico, western Texas, and western Oklahoma). A primary purpose of volume 1 is to provide information to employees of the National Forest System for managing grassland ecosystems and landscapes, both at the Forest Plan level for Plan amendments and revisions, and at the project level to place site-specific activities within the larger framework. This volume should also be useful to State, municipal, and other Federal agencies, and to private landowners who manage grasslands in the Southwestern United States.
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Chapter
The vast majority of the world’s species are insects (at least 80%; Mawdsley and Stork 1995). Their importance is overwhelming by almost any measure. For example, insects and other arthropods contribute substantially to standing biomass; 1,000 kg/ha is an estimate for the United States (Pimentel et al. 1980). In most terrestrial and freshwater ecosystems they play critical roles as prey, predators, herbivores and pollinators (Free 1970; Debach and Rosen 1991; Kellert 1993; Lloyd and Barrett 1996). Indeed, in one of the first issues of the Society for Conservation Biology’s journal, E.O. Wilson (1987) called insects “the little things that run the world.” Because they comprise the majority of the earth’s biodiversity, insects should be considered pivotal in conservation efforts (Kim 1993). Unfortunately, an alarmingly small percent of our conservation literature focusses on insect issues. For example, in 1993, 1994 and 1995, the journals Ecological Applications, Conservation Biology, and Biological Conservation published 1,070 articles with only 62 related to insect issues and still fewer related to conservation of declining insect populations. Thus, only 6% of our conservation literature is aimed at 80% of our planet’s biodiversity. This neglect of insect conservation cannot be justified on the basis of insects not being endangered. In Britain where the biodiversity is relatively well-documented, approximately 22,500 insect species occur; 43 insects are believed to have gone extinct between 1900 and 1987 (Hambler and Speight 1996). The number of insect species believed extinct in Britain is over eight times that of number of extinct vertebrates, and over three times that of flowering plants (Hambler and Speight 1996).
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The application of island biogeography theory to conservation practice is premature. Theoretically and empirically, a major conclusion of such applications—that refuges should always consist of the largest possible single area—can be incorrect under a variety of biologically feasible conditions. The cost and irreversibility of large-scale conservation programs demand a prudent approach to the application of an insufficiently validated theory.
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An analysis of the distribution of the small boreal mammals (excluding bats) on isolated mountaintops in the Great Basin led to the following conclusions: 1. The species-area curve is considerably steeper (z = .43) than the curves usually obtained for insular biotas. 2. There is no correlation between number of species of boreal mammals and variables which are likely to affect the probability of colonization, such as distance between island and mainland, distance between islands, and elevation of intervening passes. Apparently the present rate of immigration of boreal mammals to isolated mountains is effectively zero. 3. Paleontological evidence suggests that the mountains were colonized by a group of species during the Pleistocene when the climatic barriers that currently isolate them were abolished. 4. Subsequent to isolation of the mountains, extinctions have reduced the faunal diversity to present levels. Probability of extinction is inversely related to population size and, therefore, is influenced b...
In addition, much information was obtained from unpublished sources in the files of the Montana Fish and Game Department; US Forest Service; Montana Historical Library; and the Great Falls Tribune
  • Mussehl
  • Howell
Mussehl & Howell, 1971 ; Meagher, 1973; Picton & Picton, 1976. In addition, much information was obtained from unpublished sources in the files of the Montana Fish and Game Department; US Forest Service; Montana Historical Library; and the Great Falls Tribune. These references are listed in a bibliography (Picton & Picton, 1974).
Rocky mountain bighorn sheep of Montana Island biogeography and conservation: Strategy and limitations
  • F M Couey
  • Helena
  • Montana Mt
  • Game Fish
  • Dept
  • J M Diamond
COUEY, F. M. (1950). Rocky mountain bighorn sheep of Montana. Helena, MT, Montana Fish and Game Dept. DIAMOND, J. M. (1976). Island biogeography and conservation: Strategy and limitations. Science, N. Y., 193, 1027-9.
Island biogeography and the design of natural reserves The mammals of North America Big game in Montana from early historical records
  • J M Diamond
  • May
  • R M Philadelphia
  • W B Pa
  • Saunders
  • Co
  • E R Hall
  • K R @bullet Kelson
DIAMOND, J. M. 8/~ MAY, R. M. (1976). Island biogeography and the design of natural reserves. In Theoretical ecology, ed. by R. M. May, 163 86. Philadelphia, PA, W. B. Saunders Co. HALL, E. R. @BULLET KELSON, K. R. (1959). The mammals of North America, 2, New York, Ronald Press. KOCH, E. (1941). Big game in Montana from early historical records. J. Wildl. Mgmt, 5, 357-70.
The bison of Yellowstone National Park. National Park Service Monogr Mountain grassland and shrubland habitat types of western Montana Game management in Montana Book review of ecology and evolution of communities
  • M M Meagher
  • Pp
  • W F Mueggler
  • W P Handl
MEAGHER, M. M. (1973). The bison of Yellowstone National Park. National Park Service Monogr., l, 161 pp. MUEGGLER, W. F. & HANDL, W. P. (1974). Mountain grassland and shrubland habitat types of western Montana. Bozeman, MT, Intermountain Forest and Range Experiment Station, U.S. Forest Service. MUSSEHL, T. W. & HOWELL, F. W. (1971). Game management in Montana. Helena, MT, Montana Fish and Game Dept. MUUL, I. (1977). Book review of ecology and evolution of communities. J. Wildl. Mgmt, 41,343-4.
A wildlife bibliography of the Sun Rit,er, Montana Saga of the sun The canonical distribution of commonness and rarity, Part II
  • Ogden
  • Intermountain Mt
  • Range Forest
  • U S Station
  • Forest
  • Gen Service
  • Pp
  • H D Picton
  • E Picton
  • Helena
  • Montana Mt
  • Game Fish
  • Dept
  • H D Picton
  • I E Picton
  • Helena
  • Montana Mt
  • Game Fish
  • Dept
  • F W Preston
Ogden, MT, Intermountain Forest and Range Experiment Station, U.S. Forest Service, Gen. Tech. Rep. INT-34, 174 pp. PICTON, H. D. & PICTON, i. E. (1974). A wildlife bibliography of the Sun Rit,er, Montana. Helena, MT, Montana Fish and Game Dept. PICTON, H. D. & PICTON, I. E. (1976). Saga of the sun. Helena, MT, Montana Fish and Game Dept. PRESTON, F. W. (1962). The canonical distribution of commonness and rarity, Part II. Ecology, 43, 410-31.
Habitat types: An improved system for classifying Montana's forests
  • Arno
Mountain grassland and shrubland habitat types of western Montana
  • Mueggler
Island biogeography and the management of fragmented species
  • Shaffer
Big game in Montana from early historical records
  • Koch
The canonical distribution of commonness and rarity, Part II
  • Preston
Survey of the northern boundary of the United States from the Lake of the Woods to the summit of the Rocky Mountains
  • Twinning
Applied biogeography
  • Wilson
Book review of ecology and evolution of communities
  • Muul