Preface to the Princeton Landmarks in Biology Edition vii Preface xi Symbols Used xiii 1. The Importance of Islands 3 2. Area and Number of Speicies 8 3. Further Explanations of the Area-Diversity Pattern 19 4. The Strategy of Colonization 68 5. Invasibility and the Variable Niche 94 6. Stepping Stones and Biotic Exchange 123 7. Evolutionary Changes Following Colonization 145 8. Prospect 181 Glossary 185 References 193 Index 201

The Theory of Island Biogeography

A major benefit of multitemporal, remotely sensed images is their applicability to change detection over time. Because of concerns about global and environmental change, these data are becoming increasingly more important. However, to maximize the usefulness of the data from a multitemporal point of view, an easy-to-use, cost-effective, and accurate radiometric calibration and correction procedure is needed. The atmosphere effects the radiance received at the satellite by scattering, absorbing, and refracting light; corrections for these effects, as well as for sensor gains and offsets, solar irradiance, and solar zenith angles, must be included in radiometric correction procedures that are used to convert satellite-recorded digital counts to ground reflectances. To generate acceptable radiometric correction results, a model is required that typically uses in-situ atmospheric measurements and radiative transfer code (RTC) to correct for atmospheric effects. The main disadvantage of this type of correction procedure is that it requires in-situ field measurements during each satellite overflight. This is unacceptable for many applications and is often impossible, as when using historical data or when working in very remote locations. The optimum radiometric correction procedure is one based solely on the digital image and requiring no in-situ field measurements during the satellite overflight. The darkobject subtraction (DOS) method, a strictly image-based technique, is an attempt to achieve this ideal procedure. However, the accuracy is not acceptable for many applications, mostly because it corrects only for the additive scattering effect and not for the multiplicative transmittance effect. This paper presents an entirely image-based procedure that expands on the ~10s model by including a simple multiplicative correction for the effect of atmospheric transmittance. Two straightforward methods to derive the multiplicative transmittance-correction coefficient are presented. The COSITZ) or COST method uses the cosine of the solar zenith angle, which, to a first order, is a good approximation of the atmospheric transmittance for the dates und sites used in this study. The default TAUS method uses the average of the transmittance values computed by using in-situ atmospheric field measurements made during seven different satellite overflights. Published and unpublished data made available for this study by Moran et al. (1992) are used, and my model results are compared with their results. The corrections generated by the entirely image-based COST model are as accurate as those generated by the models that used in-situ atmospheric field measurements and RTC software.

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Image-Based Atmospheric Corrections - Revisited and Improved

Leu-M

Plant invasions are widely recognized as significant threats to biodiversity conservation worldwide. One way invasions can affect native ecosystems is by changing fuel properties, which can in turn affect fire behavior and, ultimately, alter fire regime characteristics such as frequency, intensity, extent, type, and seasonality of fire. If the regime changes subsequently promote the dominance of the invaders, then an invasive plant–fire regime cycle can be established. As more ecosystem components and interactions are altered, restoration of preinvasion conditions becomes more difficult. Restoration may require managing fuel conditions, fire regimes, native plant communities, and other ecosystem properties in addition to the invaders that caused the changes in the first place. We present a multiphase model describing the interrelationships between plant invaders and fire regimes, provide a system for evaluating the relative effects of invaders and prioritizing them for control, and recommend ways...

https://www.jstor.org/stable/10.1641/0006-3568%282004%29054%5B0677%3AEOIAPO%5D2.0.CO%3B2

Effects of Invasive Alien Plants on Fire Regimes

Statistics For Spatial Data

Degradation, fragmentation, and loss of native sagebrush (Artemisia spp.) landscapes have imperiled these habitats and their associated avifauna. Historically, this vast piece of the Western landscape has been undervalued: even though more than 70% of all remaining sagebrush habitat in the United States is publicly owned, <3% of it is protected as federal reserves or national parks. We review the threats facing birds in sagebrush habitats to emphasize the urgency for conservation and research actions, and synthesize existing information that forms the foundation for recommended research directions. Management and conservation of birds in sagebrush habitats will require more research into four major topics: (1) identification of primary land-use practices and their influence on sagebrush habitats and birds, (2) better understanding of bird responses to habitat components and disturbance processes of sagebrush ecosystems, (3) improved hierarchical designs for surveying and monitoring programs, and ...

https://www.fws.gov/southwest/es/documents/R2ES/LitCited/LPC_2012/Knick_et_al_2003.pdf

Teetering on the edge or too late? conservation and research issues for avifauna of sagebrush habitats

Population declines of greater sage-grouse (Centrocercus urophasianus) and alterations and loss of sagebrush (Artemisia spp.) have prompted petitions to the U.S. Fish and Wildlife Service to list the species under the Endangered Species Act. Our objectives were to present an unbiased assessment from an ecological perspective of the current status and the potential factors that influenced the long-term conservation of greater sage-grouse populations and the sagebrush ecosystems on which they depend. We reviewed the primary literature, and conducted new analyses and presented results on data collected for greater sage-grouse populations and sagebrush habitats. Our approach was large-scale, and was intended to identify regional patterns of disturbances, land use practices, and population trends. A blind review of this document was conducted by the Ecological Society of America. In addition, members of the National Sagegrouse Conservation Planning Framework Team and representatives from each state and province in the current range of greater sage-grouse reviewed the document for completeness and technical accuracy. In this chapter, we present the background, objectives, perspective, and geographical and temporal scope for the Conservation Assessment. Because 70% of the lands dominated by sagebrush cover are managed by public agencies, we summarized the primary legislation directing the historical disposition and governing the use of public lands. We also presented information on the administrative jurisdiction of sagebrush habitats because many of the stressors on sagebrush ecosystems involve land use and management practices. However, we did not provide management recommendations. Rather, this document was intended as an objective scientific presentation of the individual and cumulative influences on greater sage-grouse and sagebrush habitats. Range-wide Conservation Assessment Background and Rationale Historically, greater sage-grouse occurred in parts of 12 states within the western United States and 3 Canadian provinces (Fig. 1.1) (Schroeder et al. 2004). Greater sage-grouse populations have declined throughout much of their former range and have been extirpated from Nebraska, and British Columbia (Connelly and Braun 1997, Schroeder et al. 1999, Schroeder et al. 2004). The historical distribution of greater sage-grouse in Arizona currently is being questioned. Estimates of regional declines ranged from 17 to 47% (Connelly and Braun 1997). Greater sage-grouse currently occupy 670,000 km, or 56%, of their potential pre-settlement range, which once covered approximately 1,200,000 km (Schroeder et al. 2004). Current distributions of “fringe” populations are fragmented and increasingly disjunct from core regions of the distribution (e.g., Mono Lake, California; eastern Washington; southern Utah) (Schroeder et al. 1999). Despite widespread concerns regarding the species’ status and declining numbers, there has been no definitive range-wide assessment of sage-grouse populations and habitats. The greater sage-grouse is entirely dependent on sagebrush ecosystems that dominate much of western North America. The sagebrush biome, comprised primarily of 20 taxa encompassing 11 major Artemisia species and subspecies groups (McArthur and Plummer 1978, McArthur and Sanderson 1999), covers approximately 480,000 km (118.6 million acres) and Conservation Assessment of Greater Sage-grouse and Sagebrush Habitats Connelly et al. Introduction 1 2 includes 14 states (Washington, Oregon, California, Idaho, Nevada, Utah, Arizona, Montana, Wyoming, Colorado, New Mexico, Nebraska, South Dakota, and North Dakota) (sagebrush habitats in Oklahoma and Kansas were outside of the pre-settlement range of greater sage-grouse were not included in this assessment) and 3 provinces (Alberta, British Columbia, Saskatchewan) (Fig. 1.2). Vegetation and wildlife communities vary greatly across the range covered by sagebrush as a function of differences in underlying soils, climate, elevation, and geographic location (Miller and Eddleman 2001). The relatively simple structure and floristic characteristics of sagebrush landscapes (West 1996, West and Young 2000) mask complex community dynamics, disturbance regimes, and system resiliency. Three fundamental characteristics of the landscape that early European explorers once described as a vast sea of sagebrush (Fremont 1845) have been altered from pre-settlement conditions. First, the total land area dominated by sagebrush has been reduced in many regions of the sagebrush biome. For example, approximately 75% of the shrubsteppe habitats occurring on deep, loamy soils in the state of Washington and virtually all of the basin big sagebrush (Artemisia tridentata ssp. tridentata) habitats in southern Idaho have been converted to agricultural croplands (Hironaka et al. 1983, Noss et al. 1995, McDonald and Reese 1998, Vander Haegen et al. 2000). Second, the composition of sagebrush communities has been changed, primarily through alterations in the understory vegetation and soils. Replacement of native perennial bunchgrasses by cheatgrass (Bromus tectorum), an exotic annual, has profoundly altered the fire regime and led to extensive loss of large expanses of sagebrush habitats (d’Antonio and Vitousek 1992, West and Young 2000, Brooks and Pyke 2001). Finally, the configuration of sagebrush habitats within the larger context of the landscape has been changed. The increased edge in landscapes fragmented by roads, power-lines, fences, and other linear features promote spread of exotic invasive species (Gelbard and Belnap 2003), facilitates predator movements (Tewksbury et al. 2002), and isolates wildlife populations (Saunders et al. 1991, Trombulak and Frissell 2000). Changes in quantity, composition, and configuration of sagebrush habitats have consequences on the ecological processes within the sagebrush ecosystem and the resources available to support wildlife (Wisdom et al. 2002). Few pristine and intact sagebrush ecosystems remain (Noss and Peters 1995, Noss et al. 1995, West 1996, Mac et al. 1998). Over 350 species of flora and fauna depend on sagebrush habitats for all or part of their existence; a high proportion of the endemic and imperiled species in the western United States are found within the sagebrush distribution. The Great Basin ecoregion contains the second highest number of imperiled endemic species in the United States (Chaplin et al. 2000:166). The Columbia Basin population of pygmy rabbits (Brachylagus idahoensis) and Gunnison sagegrouse (Centrocercus minimus) are highly dependent on sagebrush habitats and currently are candidate species for federal listing under the Endangered Species Act (U.S. Fish and Wildlife Service 2000, U.S. Fish and Wildlife Service 2003). The current range occupied by Gunnison sage-grouse has been reduced to 5,000 km from its pre-settlement distribution of 45,000 km Conservation Assessment of Greater Sage-grouse and Sagebrush Habitats Connelly et al. Introduction 1 3 primarily because of habitat loss and alteration (Oyler-McCance et al. 2001, Schroeder et al. 2004). Petitions filed to list the greater sage-grouse under the Endangered Species Act are based on concerns for long-term conservation because of potential threats to the species and the sagebrush habitats on which it depends (Wambolt et al. 2002). Public perception has progressed beyond the prediction that the “much-maligned sagebrush will be regarded with increasing favor by land managers” (McArthur and Plummer 1978) to genuine concern about these ecosystems (Braun et al. 1976, Knick 1999) to requests for legal action (Chapter 2). A decision to give the greater sage-grouse protected status across its entire range has significant consequences for management and use of a large part of the western United States. Less than 1% of the 668,412 km currently occupied by greater sage-grouse, and very little sagebrush habitat is legally protected (Caicco et al. 1995, Stoms et al. 1998, Scott et al. 2001, Wright et al. 2001, Knick et al. 2003). Multiple-use management dominates approximately 70% of the sagebrush habitats, which are owned publicly (Box 1990, Poling 1991). Consumptive uses that potentially influence sagebrush habitats include livestock grazing, mining, energy development, conversion to agriculture, and urbanization. Non-consumptive uses, such as use of off-road vehicles for recreation, also have the potential to influence habitats and populations of sage-grouse. Greater sage-grouse also are legally hunted in 10 states, and some populations are also subject to subsistence hunting by Native Americans. Objectives and Perspective of the Conservation Assessment Our primary objective was to document the current status and the potential factors that influence the long-term conservation of greater sage-grouse populations and the sagebrush ecosystems on which they depend. We based our analysis throughout this document on an ecological perspective of the dynamics inherent in sagebrush ecosystems and the requirements of greater sage-grouse. In contrast, land-use perspectives have goals to maximize a particular function that may have objectives competing with other resource use. For example, evaluation of sagebrush communities primarily based on their ability to provide forage for livestock may result in extensive alterations that are unsuitable for greater sage-grouse and other species dependent on sagebrush habitats (Schneegas 1967, Klebenow 1970, Braun et al. 1976, Reynolds and Trost 1981, Crawford et al. 2004). An ecological perspective is critical to providing a common denominator within which land uses can be evaluated in relation to disturbance and resiliency of the system. We have used ecological terms to describe population or habitat patterns and processes rather than value-laden terms which may have alternate connotations. Commonly used terms, such as “decadent” or “catastrophic” evoke an attitude that somet

https://digitalcommons.usu.edu/cgi/viewcontent.cgi?article=1079&context=govdocs

Conservation assessment of greater sage-grouse and sagebrush habitats

/pdf/greater-sage-grouse-ecology-and-conservation-of-a-landscape-5g2nnuuz6m.pdf

Greater Sage-Grouse: Ecology and Conservation of a Landscape Species and Its Habitats

Anthropogenic features such as urbanization, roads, and power lines, are increasing in western United States landscapes in response to rapidly growing human populations However, their spatial effects have not been evaluated Our goal was to model the human footprint across the western United States We first delineated the actual area occupied by anthropogenic features, the physical effect area Next, we developed the human footprint model based on the ecological effect area, the zone influenced by features beyond their physical presence, by combining seven input models: three models quantified top-down anthropogenic influences of synanthropic predators (avian predators, domestic dog and cat presence risk), and four models quantified bottom-up anthropogenic influences on habitat (invasion of exotic plants, human-caused fires, energy extraction, and anthropogenic wildland fragmentation) Using independent bird population data, we found bird abundance of four synanthropic species to correlate positively with human footprint intensity and negatively for three of the six species influenced by habitat fragmentation We then evaluated the extent of the human footprint in relation to terrestrial (ecoregions) and aquatic systems (major rivers and lakes), regional management and conservation status, physical environment, and temporal changes in human actions The physical effect area of anthropogenic features covered 13% of the western United States with agricultural land (98%) being most dominant High-intensity human footprint areas (class 8-10) overlapped highly productive low-elevation private landholdings and covered 7% of the western United States compared to 48% for low- intensity areas (class 1-3), which were confined to low-productivity high-elevation federal landholdings Areas within 1 km of rivers were more affected by the human footprint compared to lakes Percentage human population growth was higher in low-intensity human footprint areas The disproportional regional effects of the human footprint on landscapes in the western United States create a challenge to management of ecosystems and wildlife populations Using footprint models, managers can plan land use actions, develop restoration scenarios, and identify areas of high conservation value at local landscapes within a regional context Moreover, human footprint models serve as a tool to stratify landscapes for studies investigating floral and faunal response to human disturbance intensity gradients

https://www.fws.gov/southwest/es/documents/R2ES/LitCited/LPC_2012/Leu_et_al_2008.pdf

The human footprint in the west: a large-scale analysis of anthropogenic impacts.

The distribution of sagebrush (Artemisia spp.) within the Sage-Grouse Conservation Area (SGCA, the historical distribution of sage-grouse buffered by 50 km) stretches from British Columbia and Saskatchewan in the north, to northern Arizona and New Mexico in the south, and from the eastern slopes of the Sierra Nevada and Cascade mountains to western South Dakota. The dominant sagebrush (sub)species as well as the composition and proportion of shrubs, grasses, and forbs varies across different ecological sites as a function of precipitation, temperature, soils, topographic position, elevation, and disturbance history. Most important to Greater Sage-Grouse ( Centrocercus urophasianus) are three subspecies of big sagebrush (Artemisia tridentata)(basin big sagebrush [A. t. ssp. tridentata], Wyoming big sagebrush [A. t. ssp. wyomingensis], and mountain big sagebrush [A. t. ssp. vaseyana]); two low or dwarf forms (little sagebrush [A. arbuscula] and black sagebrush [A. nova]); and silver sagebrush (A. cana), which occurs primarily in the northeast portion of the sage-grouse range. Invasive plant species, wildfires, and weather and climate change are major influences on sagebrush habitats and present significant challenges to their long-term conservation. Each factor is spatially pervasive across the Greater Sage-Grouse Conservation Area and has significant potential to influence processes within sagebrush communities. Cheatgrass (Bromus tectorum), the most widespread exotic annual grass, has invaded much of the lower-elevation, more xeric sagebrush landscapes across the western portion of the Greater Sage-Grouse Conservation Area. A large proportion of existing sagebrush communities are at moderate to high risk of invasion by cheatgrass. Juniper (Juniperus spp.) and pinyon (Pinus spp.) woodlands have expanded into sagebrush habitats at higher elevations creating an elevational squeeze on the sagebrush ecosystem from both extremes. Number of fires and total area burned have increased since 1980 throughout the SGCA except in the Snake River Plain, which has a long-term history of high fire disturbance. Climate change scenarios for the sagebrush region predict increasing trends in temperature, atmospheric carbon dioxide, and frequency of severe weather events that favor cheatgrass expansion and in creased fire disturbance resulting in a decline in sagebrush. Approximately 12% of the current distribution of sagebrush is predicted to be replaced by expansion of other woody vegetation for each 1°C increase in temperature. Periodic drought regularly influences sagebrush ecosystems; drought duration and severity have increased throughout the 20th century in much of the interior western Miller, R. F., S. T. Knick, D. A. Pyke, C. W. Meinke, S. E. Hanser, M. J. Wisdom, and A. L. Hild. 2011. Characteristics of sagebrush habitats and limitations to long-term conservation. Pp. 145–184 in S. T. Knick and J. W. Connelly (editors). Greater Sage-Grouse: ecology and conservation of a landscape species and its habitats. Studies in Avian Biology (vol. 38), University of California Press, Berkeley, CA.

Steven T. Knick

Papers

Teetering on the edge or too late? conservation and research issues for avifauna of sagebrush habitats

Conservation assessment of greater sage-grouse and sagebrush habitats

Greater Sage-Grouse: Ecology and Conservation of a Landscape Species and Its Habitats

The human footprint in the west: a large-scale analysis of anthropogenic impacts.

Characteristics of Sagebrush Habitats and Limitations to Long-Term Conservation