Geology topics

Kyle Joly

Publications and source records attributed to Kyle Joly.

26 records · Page 2Linked to original sources

USGS2008

Stochastic and compensatory effects limit persistence of variation in body mass of young caribou

Nutritional restriction during growth can have short- and long-term effects on fitness; however, animals inhabiting uncertain environments may exhibit adaptations to cope with variation in food availability. We examined changes in body mass in free-ranging female caribou ( Rangifer tarandus ) by measuring mass at birth and at 4, 11, and 16 months of age to evaluate the relative importance of seasonal nutrition to growth, the persistence of cohort-specific variation in body mass through time, and compensatory growth of individuals. Relative mean body mass of cohorts did not persist through time. Compensatory growth of smaller individuals was not observed in summer; however, small calves exhibited more positive change in body mass than did large calves. Compensation occurred during periods of nutritional restriction (winter) rather than during periods of rapid growth (summer) thus differing from the conventional view of compensatory growth.

Journal of Mammalogy↗

USGS2006

Simulating the influences of various fire regimes on caribou winter habitat

Caribou are an integral component of high‐latitude ecosystems and represent a major subsistence food source for many northern people. The availability and quality of winter habitat is critical to sustain these caribou populations. Caribou commonly use older spruce woodlands with adequate terrestrial lichen, a preferred winter forage, in the understory. Changes in climate and fire regime pose a significant threat to the long‐term sustainability of this important winter habitat. Computer simulations performed with a spatially explicit vegetation succession model (ALFRESCO) indicate that changes in the frequency and extent of fire in interior Alaska may substantially impact the abundance and quality of winter habitat for caribou. We modeled four different fire scenarios and tracked the frequency, extent, and spatial distribution of the simulated fires and associated changes to vegetation composition and distribution. Our results suggest that shorter fire frequencies (i.e., less time between recurring fires) on the winter range of the Nelchina caribou herd in eastern interior Alaska will result in large decreases of available winter habitat, relative to that currently available, in both the short and long term. A 30% shortening of the fire frequency resulted in a 3.5‐fold increase in the area burned annually and an associated 41% decrease in the amount of spruce–lichen forest found on the landscape. More importantly, simulations with more frequent fires produced a relatively immature forest age structure, compared to that which currently exists, with few stands older than 100 years. This age structure is at the lower limits of stand age classes preferred by caribou from the Nelchina herd. Projected changes in fire regime due to climate warming and/or additional prescribed burning could substantially alter the winter habitat of caribou in interior Alaska and lead to changes in winter range use and/or population dynamics.

Ecological Applications↗

USGS2003

Winter habitat use by female caribou in relation to wildland fires in interior Alaska

The role of wildland fire in the winter habitat use of caribou ( Rangifer tarandus ) has long been debated. Fire has been viewed as detrimental to caribou because it destroys the slow-growing climax forage lichens that caribou utilize in winter. Other researchers argued that caribou were not reliant on lichens and that fire may be beneficial, even in the short term. We evaluated the distribution of caribou relative to recent fires (<50 years old) within the current winter range of the Nelchina caribou herd in east-central Alaska. To address issues concerning independence and spatial and temporal scales, we used both conventional very high frequency and global positioning system telemetry to estimate caribou use relative to recent, known-aged burns. In addition, we used two methods to estimate availability of different habitat classes. Caribou used recently burned areas much less than expected, regardless of methodologies used. Moreover, within burns, caribou were more likely to use habitat within 500 m of the burn perimeter than core areas. Methods for determining use and availability did not have large influences on our measures of habitat selectivity.

Canadian Journal of Zoology↗

USGS2002

Evaluating the impacts of wildland fires on caribou in interior Alaska

Caribou are found throughout the boreal forests of interior Alaska, a region subject to chronic and expansive wildland fires. Fruticose lichens, if available, constitute the majority of the winter diet of caribou throughout their range and are common in mature boreal forests but largely absent from early successional stages. Fire, the dominant ecological driving force, increases vegetative diversity and productivity across the landscape but may reduce the availability of caribou winter forage for decades. Increasingly, wildland fire regimes are influenced by humans seeking to reduce fire hazards or mitigate the effects of years of fire suppression. Consequently, biologists have debated the importance of forage lichens to the dynamics of caribou populations, and land managers have questioned the importance of fire regime to wintering caribou. To better understand the impacts of wildland fire on caribou, we are simultaneously investigating the relationships between fire history, caribou movements, forage lichen availability, and caribou nutritional performance on their winter range.

Alaska↗

USGS2001

Patterns of mammalian species richness and habitat associations in Pennsylvania

Landscape variables were employed as indices of habitat heterogeneity, fragmentation, and human influence on the environment to characterize constituent units of a 635 km 2 grid covering the state of Pennsylvania. Species richness was determined by overlaying the distributions of all 60 terrestrial mammalian species found within the state. All landscape variables investigated were correlated with species richness. Areas with high topographic variation and low road density had the highest species richness. Species sensitive to habitat fragmentation were also associated with large forest patches and low road density. These landscape variables may be useful in identifying areas that are important for the conservation of these species. Associations between species distributions and landscape variables were substantiated by published habitat associations. Species with extremely limited distributions were not associated with landscape variables and represent special cases for conservation planners. Rare species, as defined by their limited geographical distribution, were not associated with areas of high species richness (hotspots). The utility of species richness hotspots for conservation planning is disputable. Hotspots of species richness were associated with large forest patches and low road density.

Pennsylvania↗

USGS2000

Orphan caribou, Rangifer tarandus , calves: A re-evaluation of overwinter survival data

Low sample size and high variation within populations reduce power of statistical tests. These aspects of statistical power appear to have affected an analysis comparing overwinter survival rates of non-orphan and orphan Caribou ( Rangifer tarandus ) calves by an earlier study for the Porcupine Caribou Herd. A re-evaluation of the data revealed that conclusions about a lack of significant difference in the overwinter survival rates between orphan and non-orphan calves were premature.

Canadian Field-Naturalist↗

USGS1998

Cultural resource applications for a GIS: Stone conservation at Jefferson and Lincoln Memorials

Geographical information systems are rapidly becoming essential tools for land management. They provide a way to link landscape features to the wide variety of information that managers must consider when formulating plans for a site, designing site improvement and restoration projects, determining maintenance projects and protocols, and even interpreting the site. At the same time, they can be valuable research tools. Standing structures offer a different sort of geography, even though a humanly contrived one. Therefore, the capability of a geographical information system (GIS) to link geographical units to the information pertinent to the site and resource management can be employed in the management of standing structures. This was the idea that inspired the use of a GIS software, ArcView, to link computer aided design CAD) drawings of the Jefferson and Lincoln Memorials with inventories of the stones in the memorials. Both the CAD drawings and the inventory were in existence; what remained to be done was to modify the CAD files and place the inventory in an appropriately designed computerized database, and then to link the two in a GIS project. This work was carried out at the NPS Denver Service Center, Resource Planning Group, Applied Archaeology Center (DSC-RPG-AAC), in Silver Spring, Maryland, with the assistance of US/ICOMOS summer interns Katja Marasovic (Croatia) and Rastislav Gromnica (Slovakia), under the supervision of AAC office manager Douglas Comer. Project guidance was provided by Tony Donald, the Denver Service Center (DSC) project architect for the restoration of the Jefferson and Lincoln Memorials, and GIS consultation services by Kyle Joly.

Cultural Resources Management↗

USGS1997

Echelon approach to areas of concern in synoptic regional monitoring

Echelons provide an objective approach to prospecting for areas of potential concern in synoptic regional monitoring of a surface variable. Echelons can be regarded informally as stacked hill forms. The strategy is to identify regions of the surface which are elevated relative to surroundings ( R elative ELEVATIONS or RELEVATIONS ). These are areas which would continue to expand as islands with receding (virtual) floodwaters. Levels where islands would merge are critical elevations which delimit echelons in the vertical dimension. Families of echelons consist of surface sectors constituting separate islands for deeper waters that merge as water level declines. Pits which would hold water are disregarded in such a progression, but a complementary analysis of pits is obtained using the surface as a virtual mould to cast a counter-surface (bathymetric analysis). An echelon tree is a family tree of echelons with peaks as terminals and the lowest level as root. An echelon tree thus provides a dendrogram representation of surface topology which enables graph theoretic analysis and comparison of surface structures. Echelon top view maps show echelon cover sectors on the base plane. An echelon table summarizes characteristics of echelons as instances or cases of hill form surface structure. Determination of echelons requires only ordinal strength for the surface variable, and is thus appropriate for environmental indices as well as measurements. Since echelons are inherent in a surface rather than perceptual, they provide a basis for computer-intelligent understanding of surfaces. Echelons are given for broad-scale mammalian species richness in Pennsylvania.

Environmental and Ecological Statistics↗