This dataset contains human population density for the state of California and a small portion of western Nevada for the year 2000. The population density is based on US Census Bureau data and has a cell size of 990 meters.

The purpose of the dataset is to provide a consistent statewide human density GIS layer for display, analysis and modeling purposes.

The state of California, and a very small portion of western Nevada, was divided into pixels with a cell size 0.98 km2, or 990 meters on each side. For each pixel, the US Census Bureau data was clipped, the total human population was calculated, and that population was divided by the area to get human density (people/km2) for each pixel.

This dataset provides long-term information about Iberian ibex (Capra pyrenaica hispanica Schimper, 1848) presence in Sierra Nevada (SE Iberian Peninsula), as a result of annual sampling from 1993 to 2018 done by the managers of the Sierra Nevada Natural and National Park. They carried out the transects collecting different variables such as the number of individuals observed, the perpendicular distance of each group of goats to the transect line and, at an individual level and sex as well as age of individuals in the case of males. These data enabled the calculation of population parameters such as density, sex ratio, birth rate and age structure. These parameters are key for Iberian ibex conservation and management, given that Sierra Nevada harbours the largest population of this species in the Iberian Peninsula. The data set we present is structured using the Darwin Core biological standard, which contains 3,091 events (582 transect walk events and 2,509 group sighting events), 5,396 occurrences, and 2,502 measurements. The occurrences include the sightings of 11,436 individuals (grouped by sex and age) from 1993 to 2018 in a total of 88 transects distributed along Sierra Nevada, of which 33 have been continuously sampled since 2008.

Vector polygon map data of city limits from Las Vegas, Nevada containing 87 features.

City limits GIS (Geographic Information System) data provides valuable information about the boundaries of a city, which is crucial for various planning and decision-making processes. Urban planners and government officials use this data to understand the extent of their jurisdiction and to make informed decisions regarding zoning, land use, and infrastructure development within the city limits.

By overlaying city limits GIS data with other layers such as population density, land parcels, and environmental features, planners can analyze spatial patterns and identify areas for growth, conservation, or redevelopment. This data also aids in emergency management by defining the areas of responsibility for different emergency services, helping to streamline response efforts during crises..

This city limits data is available for viewing and sharing as a map in a Koordinates map viewer. This data is also available for export to DWG for CAD, PDF, KML, CSV, and GIS data formats, including Shapefile, MapInfo, and Geodatabase.

This shapefile contains landscape factors representing human disturbances summarized to local and network catchments of river reaches for the state of Nevada. This dataset is the result of clipping the feature class 'NFHAP 2010 HCI Scores and Human Disturbance Data for the Conterminous United States linked to NHDPLUSV1.gdb' to the state boundary of Nevada. Landscape factors include land uses, population density, roads, dams, mines, and point-source pollution sites. The source datasets that were compiled and attributed to catchments were identified as being: (1) meaningful for assessing fish habitat; (2) consistent across the entire study area in the way that they were assembled; (3) representative of conditions in the past 10 years, and (4) of sufficient spatial resolution that they could be used to make valid comparisons among local catchment units. In this data set, these variables are linked to the catchments of the National Hydrography Dataset Plus Version 1 (NHDPlusV1) using the COMID identifier. They can also be linked to the reaches of the NHDPlusV1 using the COMID identifier. Catchment attributes are available for both local catchments (defined as the land area draining directly to a reach; attributes begin with "L_" prefix) and network catchments (defined by all upstream contributing catchments to the reach's outlet, including the reach's own local catchment; attributes begin with "N_" prefix). This shapefile also includes habitat condition scores created based on responsiveness of biological metrics to anthropogenic landscape disturbances throughout ecoregions. Separate scores were created by considering disturbances within local catchments, network catchments, and a cumulative score that accounted for the most limiting disturbance operating on a given biological metric in either local or network catchments. This assessment only scored reaches representing streams and rivers (see the process section for more details). Please use the following citation: Esselman, P., D.M. Infante, L. Wang, W. Taylor, W. Daniel, R. Tingley, J. Fenner, A. Cooper, D. Wieferich, D. Thornbrugh and J. Ross. (April 2011) National Fish Habitat Action Plan (NFHAP) 2010 HCI Scores and Human Disturbance Data (linked to NHDPLUSV1) for Nevada. National Fish Habitat Partnership Data System. http://dx.doi.org/doi:10.5066/F7Q23X78

DOCTORATE DISSERTATION: The population dynamics and behavior of a populationof beavers, Castor canadensis, at Sagehen Creek, Nevada County, CA, were investigated from June 1977 through October 1979. A total of 29 beavers from four colonies were live-trapped, assigned to age classes, sexed, marked with color coded ear tags for individual identification, fitted with radio transmitters if older than kits, and released. The primary objective of the research was to examine the similarities and differences in behavior among members of the various age-sex classes. Resting associations and locations for all radio-tagged animals were also ascertained. The population size increased by 6 individuals, and increases in population density, average length of stream occupied per colony, total length of stream occupied by all colonies, and intercolonial movement occurred during the research. The sex ratio increased from 1 male:1 female in 1977 to 1.5 males: 1 female in 1979, which resulted from the presence of four new young adult males living at the borders of the existing colonies during the summer of 1979. The age class composition also changed, with more adults and two-year olds and fewer kits present in 1979 than in previous years. Three of the four colonies were typical family groups, consisting of the mated adult pair, several yearlings and the young of the year. Reproduction occurred all three years, but not in every colony, and the average litter size was 2.33 kits. Only one known mortality occurred and this was a male kit, although several subadults of both sexes disappeared from the population. Dispersal of the subadults is thought to regulate population size, although four two-year old individuals remained with their parent colonies at the termination of the research. The observed population changes suggest that the carrying capacity of the habitat for beavers has been reached and that the growth of the population should slow down or cease during the next few years. Seventeen types of behavior, which were grouped into three categories based on biological function, were recorded. Younger animals had a higher rate of occurrence of personal maintenance and social behaviors, while older animals had a higher rate for colony maintenance behaviors. Adult males had the highest rate of colony maintenance during both the summer and fall, and males of all age classes (excluding kits) had higher rates of colony maintenance in the fall than females. Adult males are considered to invest in the family group primarily through the performance of colony maintenance behaviors. Kits had the highest rate of social behaviors and initiated the most encounters with other beavers. The adult females were involved in the most interactions and had the lowest frequency of submissive interactions. The adult males had the highest frequency of dominant interactions. An age class dominance hierarchy was present within the families, with older age classes always dominant to younger age classes. No evidence for a sexual hierarchy was found, and the adults within a colony were considered to be codominant. Beavers in all colonies used a number of rest sites, both lodges and bank burrows. Most colonies had one preferred rest site that was used by all members, while some colonies had two preferred rest sites. Use of rst sites and resting associations were affected by season of the year, number of young in the family, and specific age of the adults in the mated pair.

Data from: Abundance models of endemic birds of the Sierra Nevada de Santa Marta, northern South America, suggest small population sizes and dependence on montane elevations

https://doi.org/10.5061/dryad.5dv41nscw

MS Reference Number: ORNITH-APP-23-061R2 Dataset name: Abundance_models_priority_endemics_SNSM.xlsx

The whole dataset contains data for fitting hierarchical distance-sampling models for priority, endemic bird species from the Sierra Nevada de Santa Marta, northern Colombia. Models were used to assess elevation- and habitat-related variation in local abundance and obtain values of population density and total and effective population size for the study species. Details on other methods used for estimating extent of presence (EOP) and area of occupancy (AOO), and for generating abundance maps are provided in the manuscript and the supplementary material file that accompanies it. Abundance maps will be uploaded as distribution hypothesis for each species to the BioModelos ...

DOCTORATE DISSERTATION:Studies were carried out in Tilden Park, Contra Costa County, and Sagehen Creek, Nevada County, California., from 1951 to 1955. Population trends of Microtus montanus at Sagehen Creek and Microtus californicus at Tilden Park showed no interspecific synchrony. A local population of sooty grouse (Dendragapus fuliginosus) at Sagehen Creek also showed little indication of synchrony between the long grouse-hare cycle and the short microtine cycle. Both M. montanus and M. californicus exhibit an inverse relationship between population density and natality, as measured by ovulation rate and litter size. The age at which reproductive maturity is reached is apparently quite constant and independent of the stage of the population cycle. In M. montanus the length of the breeding season and seasonal litter production changed only slightly, declining as population density increased up to the cyclic peak. In contrast, length of the breeding season and litter production varied considerably in M. californicus. The conclusion reached is that variable reproduction is not a cause of the cyclic changes observed in population density. Thus, mortality must be the variable that produces the differences in populations from year to year. The population of adult voles immediately prior to the beginning of the breeding season is about the same each year. The level that the population reaches at the end of each breeding season depends upon the survival of individuals born during that breeding season. Changes in the survival rates of young voles are considered to be the main cause of the population differences found in the summer and autumn of the different years. Incidental to the work on population cycles, certain basic aspects of comparative reproduction have been uncovered. In M. californicus, a vole with a long breeding season, litter size is small and precocious breeding is rare. M. montanus, with a short breeding season, has large litters, and precocious breeding and polyovuly are common. Another difference between the species is that litter size is highest at the start of the breeding season in M. montanus, and then progressively declines. In M. californicus, litter size is initially low, rises to a peak in the middle of the breeding season, and then declines again. This pattern correlates with changes in the quality of forage available to the voles. A possible nutritional basis for the population fluctuations was investigated by applying commercial nitrogen and phosphorus fertilizer to several of the meadows at Sagehen Creek in 1954. The M. montanus population apparently responded to the fertilization in that the decline in numbers during the summer of 1954 was not as severe in the fertilized meadows as in the unfertilized meadows, and breeding was prolonged. The response was, however, temporary. A side study on Sooty Grouse was undertaken in Sagehen Creek Basin. The major objectives were to devise some was of determining the relative abundance of the grouse from year to year, and to get some measure of the annual reproduction.

A shapefile representing greater sage-grouse (hereafter sage-grouse) space use and lek abundance in the Bi-State Distinct Population Segment (DPS) of California and Nevada. These data were derived by combining a kernel density estimation of sage-grouse lek abundance combined with another raster representing distance to lek. The 85 percent isopleth was then used to define "high space-use."

description: After each decennial census, the Census Bureau delineates urban areas that represent densely developed territory, encompassing residential, commercial, and other nonresidential urban land uses. In general, this territory consists of areas of high population density and urban land use resulting in a representation of the "urban footprint." There are two types of urban areas: urbanized areas (UAs) that contain 50,000 or more people and urban clusters (UCs) that contain at least 2,500 people, but fewer than 50,000 people (except in the U.S. Virgin Islands and Guam which each contain urban clusters with populations greater than 50,000). Each urban area is identified by a 5-character numeric census code that may contain leading zeroes.
The primary legal divisions of most states are termed counties. In Louisiana, these divisions are known as parishes. In Alaska, which has no counties, the equivalent entities are the organized boroughs, city and boroughs, municipalities, and for the unorganized area, census areas. The latter are delineated cooperatively for statistical purposes by the State of Alaska and the Census Bureau. In four states (Maryland, Missouri, Nevada, and Virginia), there are one or more incorporated places that are independent of any county organization and thus constitute primary divisions of their states. These incorporated places are known as independent cities and are treated as equivalent entities for purposes of data presentation. The District of Columbia and Guam have no primary divisions, and each area is considered an equivalent entity for purposes of data presentation. The Census Bureau treats the following entities as equivalents of counties for purposes of data presentation: Municipios in Puerto Rico, Districts and Islands in American Samoa, Municipalities in the Commonwealth of the Northern Mariana Islands, and Islands in the U.S. Virgin Islands. The entire area of the United States, Puerto Rico, and the Island Areas is covered by counties or equivalent entities.
The boundaries for counties and equivalent entities are as of January 1, 2010.; abstract: After each decennial census, the Census Bureau delineates urban areas that represent densely developed territory, encompassing residential, commercial, and other nonresidential urban land uses. In general, this territory consists of areas of high population density and urban land use resulting in a representation of the "urban footprint." There are two types of urban areas: urbanized areas (UAs) that contain 50,000 or more people and urban clusters (UCs) that contain at least 2,500 people, but fewer than 50,000 people (except in the U.S. Virgin Islands and Guam which each contain urban clusters with populations greater than 50,000). Each urban area is identified by a 5-character numeric census code that may contain leading zeroes.
The primary legal divisions of most states are termed counties. In Louisiana, these divisions are known as parishes. In Alaska, which has no counties, the equivalent entities are the organized boroughs, city and boroughs, municipalities, and for the unorganized area, census areas. The latter are delineated cooperatively for statistical purposes by the State of Alaska and the Census Bureau. In four states (Maryland, Missouri, Nevada, and Virginia), there are one or more incorporated places that are independent of any county organization and thus constitute primary divisions of their states. These incorporated places are known as independent cities and are treated as equivalent entities for purposes of data presentation. The District of Columbia and Guam have no primary divisions, and each area is considered an equivalent entity for purposes of data presentation. The Census Bureau treats the following entities as equivalents of counties for purposes of data presentation: Municipios in Puerto Rico, Districts and Islands in American Samoa, Municipalities in the Commonwealth of the Northern Mariana Islands, and Islands in the U.S. Virgin Islands. The entire area of the United States, Puerto Rico, and the Island Areas is covered by counties or equivalent entities.
The boundaries for counties and equivalent entities are as of January 1, 2010.

The 2015 cartographic boundary shapefiles are simplified representations of selected geographic areas from the U.S. Census Bureau's Master Address File / Topologically Integrated Geographic Encoding and Referencing (MAF/TIGER) Database (MTDB). These boundary files are specifically designed for small-scale thematic mapping. When possible, generalization is performed with the intent to maintain the hierarchical relationships among geographies and to maintain the alignment of geographies within a file set for a given year. Geographic areas may not align with the same areas from another year. Some geographies are available as nation-based files while others are available only as state-based files. The records in this file allow users to map the parts of Urban Areas that overlap a particular county. After each decennial census, the Census Bureau delineates urban areas that represent densely developed territory, encompassing residential, commercial, and other nonresidential urban land uses. In general, this territory consists of areas of high population density and urban land use resulting in a representation of the "urban footprint." There are two types of urban areas: urbanized areas (UAs) that contain 50,000 or more people and urban clusters (UCs) that contain at least 2,500 people, but fewer than 50,000 people (except in the U.S. Virgin Islands and Guam which each contain urban clusters with populations greater than 50,000). Each urban area is identified by a 5-character numeric census code that may contain leading zeroes. The primary legal divisions of most states are termed counties. In Louisiana, these divisions are known as parishes. In Alaska, which has no counties, the equivalent entities are the organized boroughs, city and boroughs, municipalities, and for the unorganized area, census areas. The latter are delineated cooperatively for statistical purposes by the State of Alaska and the Census Bureau. In four states (Maryland, Missouri, Nevada, and Virginia), there are one or more incorporated places that are independent of any county organization and thus constitute primary divisions of their states. These incorporated places are known as independent cities and are treated as equivalent entities for purposes of data presentation. The District of Columbia and Guam have no primary divisions, and each area is considered an equivalent entity for purposes of data presentation. The Census Bureau treats the following entities as equivalents of counties for purposes of data presentation: Municipios in Puerto Rico, Districts and Islands in American Samoa, Municipalities in the Commonwealth of the Northern Mariana Islands, and Islands in the U.S. Virgin Islands. The entire area of the United States, Puerto Rico, and the Island Areas is covered by counties or equivalent entities. The boundaries for counties and equivalent entities are as of January 1, 2010.

20 year Projected Urban Growth scenarios. Base year is 2000. Projected year in this dataset is 2020.

By 2020, most forecasters agree, California will be home to between 43 and 46 million residents-up from 35 million today. Beyond 2020 the size of California's population is less certain. Depending on the composition of the population, and future fertility and migration rates, California's 2050 population could be as little as 50 million or as much as 70 million. One hundred years from now, if present trends continue, California could conceivably have as many as 90 million residents.

Where these future residents will live and work is unclear. For most of the 20th Century, two-thirds of Californians have lived south of the Tehachapi Mountains and west of the San Jacinto Mountains-in that part of the state commonly referred to as Southern California. Yet most of coastal Southern California is already highly urbanized, and there is relatively little vacant land available for new development. More recently, slow-growth policies in Northern California and declining developable land supplies in Southern California are squeezing ever more of the state's population growth into the San Joaquin Valley.

How future Californians will occupy the landscape is also unclear. Over the last fifty years, the state's population has grown increasingly urban. Today, nearly 95 percent of Californians live in metropolitan areas, mostly at densities less than ten persons per acre. Recent growth patterns have strongly favored locations near freeways, most of which where built in the 1950s and 1960s. With few new freeways on the planning horizon, how will California's future growth organize itself in space? By national standards, California's large urban areas are already reasonably dense, and economic theory suggests that densities should increase further as California's urban regions continue to grow. In practice, densities have been rising in some urban counties, but falling in others.

These are important issues as California plans its long-term future. Will California have enough land of the appropriate types and in the right locations to accommodate its projected population growth? Will future population growth consume ever-greater amounts of irreplaceable resource lands and habitat? Will jobs continue decentralizing, pushing out the boundaries of metropolitan areas? Will development densities be sufficient to support mass transit, or will future Californians be stuck in perpetual gridlock? Will urban and resort and recreational growth in the Sierra Nevada and Trinity Mountain regions lead to the over-fragmentation of precious natural habitat? How much water will be needed by California's future industries, farms, and residents, and where will that water be stored? Where should future highway, transit, and high-speed rail facilities and rights-of-way be located? Most of all, how much will all this growth cost, both economically, and in terms of changes in California's quality of life?

Clearly, the more precise our current understanding of how and where California is likely to grow, the sooner and more inexpensively appropriate lands can be acquired for purposes of conservation, recreation, and future facility siting. Similarly, the more clearly future urbanization patterns can be anticipated, the greater our collective ability to undertake sound city, metropolitan, rural, and bioregional planning.

Consider two scenarios for the year 2100. In the first, California's population would grow to 80 million persons and would occupy the landscape at an average density of eight persons per acre, the current statewide urban average. Under this scenario, and assuming that 10% percent of California's future population growth would occur through infill-that is, on existing urban land-California's expanding urban population would consume an additional 5.06 million acres of currently undeveloped land. As an alternative, assume the share of infill development were increased to 30%, and that new population were accommodated at a density of about 12 persons per acre-which is the current average density of the City of Los Angeles. Under this second scenario, California's urban population would consume an additional 2.6 million acres of currently undeveloped land. While both scenarios accommodate the same amount of population growth and generate large increments of additional urban development-indeed, some might say even the second scenario allows far too much growth and development-the second scenario is far kinder to California's unique natural landscape.

This report presents the results of a series of baseline population and urban growth projections for California's 38 urban counties through the year 2100. Presented in map and table form, these projections are based on extrapolations of current population trends and recent urban development trends. The next section, titled Approach, outlines the methodology and data used to develop the various projections. The following section, Baseline Scenario, reviews the projections themselves. A final section, entitled Baseline Impacts, quantitatively assesses the impacts of the baseline projections on wetland, hillside, farmland and habitat loss.

The 2019 cartographic boundary KMLs are simplified representations of selected geographic areas from the U.S. Census Bureau's Master Address File / Topologically Integrated Geographic Encoding and Referencing (MAF/TIGER) Database (MTDB). These boundary files are specifically designed for small-scale thematic mapping. When possible, generalization is performed with the intent to maintain the hierarchical relationships among geographies and to maintain the alignment of geographies within a file set for a given year. Geographic areas may not align with the same areas from another year. Some geographies are available as nation-based files while others are available only as state-based files. The records in this file allow users to map the parts of Urban Areas that overlap a particular county. After each decennial census, the Census Bureau delineates urban areas that represent densely developed territory, encompassing residential, commercial, and other nonresidential urban land uses. In general, this territory consists of areas of high population density and urban land use resulting in a representation of the ""urban footprint."" There are two types of urban areas: urbanized areas (UAs) that contain 50,000 or more people and urban clusters (UCs) that contain at least 2,500 people, but fewer than 50,000 people (except in the U.S. Virgin Islands and Guam which each contain urban clusters with populations greater than 50,000). Each urban area is identified by a 5-character numeric census code that may contain leading zeroes. The primary legal divisions of most states are termed counties. In Louisiana, these divisions are known as parishes. In Alaska, which has no counties, the equivalent entities are the organized boroughs, city and boroughs, municipalities, and for the unorganized area, census areas. The latter are delineated cooperatively for statistical purposes by the State of Alaska and the Census Bureau. In four states (Maryland, Missouri, Nevada, and Virginia), there are one or more incorporated places that are independent of any county organization and thus constitute primary divisions of their states. These incorporated places are known as independent cities and are treated as equivalent entities for purposes of data presentation. The District of Columbia and Guam have no primary divisions, and each area is considered an equivalent entity for purposes of data presentation. The Census Bureau treats the following entities as equivalents of counties for purposes of data presentation: Municipios in Puerto Rico, Districts and Islands in American Samoa, Municipalities in the Commonwealth of the Northern Mariana Islands, and Islands in the U.S. Virgin Islands. The entire area of the United States, Puerto Rico, and the Island Areas is covered by counties or equivalent entities. The generalized boundaries for counties and equivalent entities are as of January 1, 2010.

This dataset represents inputs for a hierarchical Bayesian model of bird population density with respect to fire history in Yosemite National Park (YOSE) and Sequoia and Kings Canyon National Parks (SEKI). The model uses avian point-count data, fire history data and biophysical metrics to assess localized bird population response to years-since-fire and burn severity at thousands of locations across these parks (Ray et al. 2025). Avian point-count time series were generated by The Institute for Bird Populations in collaboration with the Sierra Nevada Inventory and Monitoring Network (SIEN) of the U.S. National Park Service (Siegel & DeSante 2002, Siegel & Wilkerson 2005, Siegel et al. 2010). Fire dates and boundaries were provided by SIEN staff. Biophysical data were accessed from on-line repositories (LANDFIRE and LEMMA GNN). For more information, please refer to Ray et al. 2025. LANDFIRE 2020. 2020. Biophysical Settings (BPS) CONUS. LANDFIRE, Earth Resources Observation and Science Center (EROS), U.S. Geological Survey. Accessed 19 May 2023, at https://www.landfire.gov/viewer/. Ray C. 2025. SIEN birds and fire. GitHub repository, https://github.com/birdpop/firebird. Ray C, Siegel RB, Wilkerson RL, Schofield L, Tingley MW, Aronson S, Haultain S, Stock S, van Wagtendonk K. Fire gives avian populations a rapid and enduring boost in protected forests of California. Siegel RB, DeSante DF. 2002. Avian inventory of Yosemite National Park (1998-2000). Report to Yosemite National Park. The Institute for Bird Populations, Point Reyes Station, CA. https://irma.nps.gov/DataStore/Reference/Profile/569146. Siegel RB, Wilkerson RL. 2005. Landbird inventory for Sequoia and Kings Canyon National Park (2003-2004). Report to Sequoia and Kings Canyon National Parks. The Institute for Bird Populations, Point Reyes Station, CA. https://irma.nps.gov/DataStore/Reference/Profile/627505. Siegel RB, Wilkerson RL, Goldin Rose M. 2010. Bird monitoring protocol for national parks in the Sierra Nevada Network. Natural Resource Report NPS/SIEN/NRR—2010/231. National Park Service, Fort Collins, Colorado. https://irma.nps.gov/DataStore/Reference/Profile/2124954