Accuracy of vegetation cover fractions, computed with spectral mixture analysis, may be compromised by variation in canopy structure and biochemistry when a single endmember represents top-of-canopy reflectance. In this article, variability is incorporated into analysis representing each set or bundle spectra, which could reasonably the reflectance an instance endmember. Endmember bundles are constructed from data itself extension to previously described method manually deriving endmembers...

Abstract Although local increases in woody plant cover have been documented arid and semiarid ecosystems worldwide, there few long‐term, large‐scale analyses of changes aboveground carbon (C) stocks. We used historical aerial photography, contemporary Landsat satellite data, field observations, image analysis techniques to assess spatially specific vegetation C stocks between 1937 1999 a 400‐km 2 region northern Texas, USA. Changes land were then related topo‐edaphic setting land‐use...

Relationships among vegetation, wind, snow, and temperature regimes may help predict effects of climate change. This paper presents a hierarchic geographic information system (HGIS) which helps examine links between species distributions at the plot level, level landscape patterns plant communities, regional greeness. Geographically referencing ecological data, mapping techniques, scale mapping, linking ground-level observations to remotely sensed are all discussed. Results include...

Interactions between multiple disturbances are of special concern in ecology due to their potential for non-linear behavior and long-lasting legacies on landscape structure function. If overcome the ecological resilience a system, alternate stable states possible. Increases frequency severity disturbance events as result climate change heighten this concern. This study directly addresses question ecosystem face disturbances. We investigated gradient interaction severities two subalpine...

Abstract When woody plant abundance increases in grasslands and savannas, a phenomenon widely observed worldwide, there is considerable uncertainty as to whether aboveground net primary productivity (ANPP) ecosystem carbon (C) nitrogen (N) pools increase, decrease, or remain the same. We estimated ANPP C N vegetation surface soils on shallow clay loam undergoing encroachment by Prosopis glandulosa Southern Great Plains of United States. Aboveground mass increased linearly, logarithmically,...

Woody plant abundance is widely recognized to have increased in savannas and grasslands worldwide. The lack of information on the rates, dynamics, extent increases shrub a major source uncertainty assessing how this vegetation change has influenced biogeochemical cycles. Projecting future consequences woody cover ecosystem function will require knowledge where present-day stands lies relative realizable maximum for given soil type within bioclimatic region. We used time-series aerial...

Abstract Aim Over the past several decades, wildfires have become larger, more frequent, and/or severe in many areas. Simultaneously, anthropogenic ignitions are steadily growing. We little understanding of how increasing changing modern fire regimes. Location Conterminous United States. Time period 1984–2016. Major taxa studied Vegetation. Methods aggregated radiative power (FRP)‐based intensity, event size, burned area, frequency, season length, and ignition type data from > 1.8 million...

Near infrared reflectance spectroscopy was evaluated as a method for measuring nitrogen and lignin content in foliage of native forest prairie species. spectra (1590 to 2357 nm) were obtained 163 samples dried green leaves leaf litter from 18 deciduous 2 coniferous tree Forty additional grass Reflectance (R) recorded log (1/R) transformed the first second derivative (1/R). Multiple linear regressions, predicting wet chemistry values based on near spectra, yielded correlation coefficients...

The complexity of earth system processes results from interactions among the physical, chemical, and biological subsystems that vary in both time space. Gaining an understanding these dynamics has taken on great importance context current environmental change portent even larger scale global change. Appreciation for concept scaling is increasing as we are challenged to integrate data models different disciplines space scales. In particular, biophysical ecological information, intrinsically...

Abstract High spectral resolution Airborne Imaging Spectrometer (AIS) data were acquired over 20 well-studied Wisconsin forest sites to evaluate the potential of remote sensing for estimating canopy chemistry. Intensive nutrient cycling research in these forests demonstrates that lignin content is strongly related measured annual nitrogen mineralization at undisturbed and may serve as an accurate index rates. Ground measurements made foliar biomass content, latter within two weeks AIS...

The fraction of photosynthetically active radiation absorbed by plant canopies (fAPAR) is a critical biophysical variable for extrapolating ecophysiological measurements from the leaf to landscape scale. Quantification fAPAR determinants at level needed improve interpretation remote sensing data, facilitate its use in constraining ecosystem process models, and synoptic-scale links between carbon nutrient cycles. Most canopy budget studies have focused on light attenuation canopies, with...

Wild pollinators provide important services to both wild and human-dominated ecosystems, yet this group may be threatened by widespread anthropogenic landscape change. Suburban sprawl is one of the fastest growing types land use change in North America, it has certain characteristics, such as abundant floral resources, that beneficial for many pollinators. We examined effects on bee assemblage shortgrass steppe Front Range Colorado, USA. Diversity, abundance, community composition bees...

Global grasslands are typically under management practices (such as fire and grazing) that alter nutrient cycling, ecosystem composition, distribution of organic matter from the unmanaged condition. We evaluated landscape-level response to grazing treatments in Konza Tallgrass Prairie Research Natural Area, Kansas, using spectral mixture analysis Airborne Visible/Infrared Imaging Spectrometer (AVIRIS) data acquired 31 August 1990. Spectral derives fractional abundances spectrally unique...