Browsing UMBC Geography and Environmental Systems Department by Issue Date

Now showing items 1-20 of 302

    • Soil Moisture Gradients and Controls on a Southern Appalachian Hillslope from Drought Through Recharge 

      Yeakley, J. Alan; Swank, W. T.; Swift, L. W.; Homberger, G. M.; Shugart, H. H. (European Geosciences Union, 1998)
      Soil moisture gradients along hillslopes in humid watersheds, although indicated by vegetation gradients and by studies using models, have been difficult to confirm empirically. While soil properties and topographic features ...

    • Multiple Source Pools and Dispersal Barriers for Galápagos Plant Species Distribution 

      Yeakley, J. Alan; Weishampel, John F. (Wiley, 2000)
      We reexamined geographic factors explaining the number of plant species on islands in the Galápagos Archipelago. We hypothesized that plant species richness (S) was related to the number of source pools and that plant ...

    • Applications of Geographic Analysis in Parole and Probation 

      Harries, Keith (2001-08)
      The advent of community-based supervision in parole and probation agencies has led to a new need for detailed location information. Three staff members received intensive training in the application of GIS tools to data ...

    • Fluorescence responses from nitrogen plant stress in 4 Fraunhofer band regions 

      McMurtrey, J.E.; Middleton, E.M.; Corp, L.A.; Campbell, Petya Entcheva; Butcher, L.M.; Chappelle, E.W.; Cook, W.B. (IEEE, 2002-11-07)
      The potential of solar Fraunhofer line features centered at 532, 607, 677 and 745nm for tracking changes in plant canopy chlorophyll content and photosynthetic capacity was studied. Excitation wavelengths similar to full ...

    • "Red edge" optical properties of corn leaves from different nitrogen regimes 

      Middleton, E.M.; Campbell, Petya Entcheva; McMurtrey, J.E.; Corp, L.A.; Butcher, L.M.; Chappelle, E.W. (IEEE, 2002-11-07)
      High resolution (<2 nm) optical spectra and biophysical measurements were acquired from corn leaves from field plots having four nitrogen fertilizer application rates: 20%, 50%, 100% and 150% of optimal levels. Reflectance ...

    • Hillslope Nutrient Dynamics Following Upland Riparian Vegetation Disturbance 

      Yeakley, J. Alan; Coleman, David C.; Haines, Bruce L.; Kloeppel, Brian D.; Meyer, Judy L.; Swank, Wayne T.; Argo, Barry W.; Deal, James M.; Taylor, Sharon F. (Springer, 2003)
      We investigated the effects of removing near-stream Rhododendron and of the natural blowdown of canopy trees on nutrient export to streams in the southern Appalachians. Transects were instrumented on adjacent hillslopes ...

    • Optical and fluorescence properties of corn leaves from different nitrogen regimes 

      Middleton, Elizabeth M.; McMurtrey III, James E.; Campbell, Petya Entcheva; Corp, Lawrence A.; Butcher, L. Maryn; Chappelle, Emmett W. (SPIE, 2003-03-17)
      The important role of nitrogen (N) in limiting or enhancing vegetation productivity is relatively well understood, although the interaction of N with other environmental variables in natural and agricultural ecosystems ...

    • Leaf diversity alters litter breakdown in a Piedmont stream 

      Swan, Christopher; Palmer, Margaret A. (University of Chicago Press, 2004-01)
      Work in terrestrial ecosystems has suggested that the breakdown rate of leaf litter may not change predictably with increasing plant species richness. Indeed, it may be that certain combinations of leaf species demonstrate ...

    • Foliar reflectance and fluorescence responses for plants under nitrogen stress determined with active and passive systems 

      Middleton, E.M.; McMurtrey, J.E.; Campbell, Petya Entcheva; Corp, L.A.; Butcher, L.M.; Chapelle, E.W. (IEEE, 2004-05-10)
      Leaves of corn (Zea mays L.) and soybean (Glycine max L.) plants were examined in a set of four experiments conducted in the summer of 2001 at USDA in Beltsville, MD. Red edge reflectance spectra and red (R) and far-red ...

    • Optical reflectance and fluorescence for detecting nitrogen needs in Zea mays L 

      McMurtrey, J.E.; Middleton, E.M.; Corp, L.A.; Campbell, Petya Entcheva; Butcher, L.M.; Daughtry, C.S.T. (IEEE, 2004-05-10)
      Nitrogen (N) status in field grown corn (Zea mays L.) was assessed using spectral techniques. Passive airborne hyperspectral reflectance remote sensing, passive leaf level reflectance, and both passive and active leaf level ...

    • Influence of land use on the integrity of marsh bird communities of Chesapeake Bay, USA 

      DeLuca, William V.; Studds, Colin E.; Rockwood, Larry L.; Marra, Peter P. (Springer Netherlands, 2004-12)
      The landscape within the Chesapeake Bay watershed has been and continues to be impacted by human modifications. Understanding if such anthropogenic disturbances influence organisms that are dependent upon estuarine wetlands ...

    • Detection of initial damage in Norway spruce canopies using hyperspectral airborne data 

      Campbell, Petya Entcheva; Rock, B. N.; Martin, M. E.; Neefus, C. D.; Irons, J. R.; Middleton, E. M.; Albrechtova, J. (Taylor and Francis, 2004-12)
      Current broadband sensors are not capable of separating the initial stages of forest damage. The current investigation evaluates the potential of hyperspectral data for detecting the initial stages of forest damage at the ...

    • Leaf litter diversity leads to non-additivity in stream detritivore colonization dynamics 

      SWAN, CHRISTOPHER; PALMER, MARGARET A. (Sciendo, 2005-01)
      Resource heterogeneity in the lake littoral zones and streams often takes the form of leaf litter diversity. Since resource quality varies between leaf species, diversity of leaf litter inputs to these systems may alter ...

    • Fluorescence imaging techniques for monitoring vegetation 

      Campbell, Petya Entcheva; Middleton, E.M.; Corp, L.A.; McMurtrey, J.E.; Kim, M.S.; Chappelle, E.W.; Butcher, L.M. (IEEE, 2005-08-08)
      Fluorescence sensing systems for the remote assessment of vegetative parameters are currently being developed and tested for use from a variety of sensing platforms. Multi-spectral fluorescence imaging techniques are being ...

    • Contribution of chlorophyll fluorescence to the reflectance of corn foliage 

      Campbell, Petya Entcheva; Middleton, E.M.; Corp, L.A.; McMurtrey, J.E.; Kim, M.S.; Chappelle, E.W.; Butcher, L.M. (IEEE, 2005-08-08)
      To assess the contribution of chlorophyll fluorescence (ChlF) to apparent reflectance (Ra) in the red/far-red, spectra were collected on a C/sub 4/ agricultural species (corn, Zea mays L.) under conditions ranging from ...

    • Fluorescence sensing techniques for vegetation assessment 

      Corp, Lawrence A.; Middleton, Elizabeth M.; McMurtrey, James E.; Campbell, Petya Entcheva; Butcher, L. Maryn (Optica, 2005-08-25)
      Active fluorescence (F) sensing systems have long been suggested as a means to identify species composition and determine physiological status of plants. Passive F systems for large-scale remote assessment of vegetation ...

    • Nonbreeding Habitat Occupancy And Population Processes: An Upgrade Experiment With A Migratory Bird 

      Studds, Colin E.; Marra, Peter P. (Ecological Society of America, 2005-09-01)
      Evidence is accumulating that winter habitats occupied by migratory birds produce differences in individual condition that can carry over into subsequent stages of the annual cycle. Despite strong observational evidence, ...

    • Loss of foundation species: consequences for the structure and dynamics of forested ecosystems 

      Ellison, Aaron M.; Bank, Michael S.; Clinton, Barton D.; Colburn, Elizabeth A.; Elliott, Katherine; Ford, Chelcy R.; Foster, David R.; Kloeppel, Brian D.; Knoepp, Jennifer D.; Lovett, Gary M.; Mohan, Jacqueline; Orwig, David A.; Rodenhouse, Nicholas L.; Sobczak, William V.; Stinson, Kristina A.; Stone, Jeffrey K.; Swan, Christopher; Thompson, Jill; Holle, Betsy Von; Webster, Jackson R. (Wiley, 2005-11-01)
      In many forested ecosystems, the architecture and functional ecology of certain tree species define forest structure and their species-specific traits control ecosystem dynamics. Such foundation tree species are declining ...

    • Deriving chlorophyll fluorescence emissions of vegetation canopies from high resolution field reflectance spectra 

      Middleton, Elizabeth M.; Corp, Lawrence A.; Daughtry, Craig S.T.; Campbell, Petya Entcheva; Butcher, L. Maryn (SPIE, 2005-11-08)
      Fluorescence of foliage in the laboratory has proven more rigorous than reflectance for correlation to plant physiology. Especially useful are emissions produced from two stable red and far-red chlorophyll fluorescence ...

    • Property Crimes and Violence in United States: An Analysis of the influence of Population density 

      Harries, Keith (2006-07)
      The role of population density in the generation or suppression of crime has been the subject of debate for decades. The classic argument is that high density offers opportunities for property crimes, given that it is a ...