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Full-Text Articles in Life Sciences
Drone Imagery Protocols To Map Vegetation Are Transferable Between Dryland Sites Across An Elevational Gradient, Anna Roser, Josh Enterkine, Juan M. Requena-Mullor, Nancy F. Glenn, Alex R. Boehm, Marie-Anne De Graaff, Patrick E. Clark, Fred Pierson, T. Trevor Caughlin
Drone Imagery Protocols To Map Vegetation Are Transferable Between Dryland Sites Across An Elevational Gradient, Anna Roser, Josh Enterkine, Juan M. Requena-Mullor, Nancy F. Glenn, Alex R. Boehm, Marie-Anne De Graaff, Patrick E. Clark, Fred Pierson, T. Trevor Caughlin
Biology Faculty Publications and Presentations
The structure and composition of plant communities in drylands are highly variable across scales, from microsites to landscapes. Fine spatial resolution field surveys of dryland plants are essential to unravel the impact of climate change; however, traditional field data collection is challenging considering sampling efforts and costs. Unoccupied aerial systems (UAS) can alleviate this challenge by providing standardized measurements of plant community attributes with high resolution. However, given widespread heterogeneity in plant communities in drylands, and especially across environmental gradients, the transferability of UAS imagery protocols is unclear. Plant functional types (PFTs) are a classification scheme that aggregates the diversity …
Pre-Emptive Detection Of Mature Pine Drought Stress Using Multispectral Aerial Imagery, Nancy Grulke, Jason Maxfield, Phillip Riggan, Charlie Schrader-Patton
Pre-Emptive Detection Of Mature Pine Drought Stress Using Multispectral Aerial Imagery, Nancy Grulke, Jason Maxfield, Phillip Riggan, Charlie Schrader-Patton
Biology Faculty Publications and Presentations
Drought, ozone (O3), and nitrogen deposition (N) alter foliar pigments and tree crown structure that may be remotely detectable. Remote sensing tools are needed that pre-emptively identify trees susceptible to environmental stresses could inform forest managers in advance of tree mortality risk. Jeffrey pine, a component of the economically important and widespread western yellow pine in North America was investigated in the southern Sierra Nevada. Transpiration of mature trees differed by 20% between microsites with adequate (mesic (M)) vs. limited (xeric (X)) water availability as described in a previous study. In this study, in-the-crown morphological traits (needle chlorosis, …
Fearscapes: Mapping Functional Properties Of Cover For Prey With Terrestrial Lidar, Peter J. Olsoy, Jennifer S. Forbey, Janet L. Rachlow, Jordan D. Nobler, Nancy F. Glenn, Lisa A. Shipley
Fearscapes: Mapping Functional Properties Of Cover For Prey With Terrestrial Lidar, Peter J. Olsoy, Jennifer S. Forbey, Janet L. Rachlow, Jordan D. Nobler, Nancy F. Glenn, Lisa A. Shipley
Biology Faculty Publications and Presentations
Heterogeneous vegetation structure can create a variable landscape of predation risk—a fearscape—that influences the use and selection of habitat by animals. Mapping the functional properties of vegetation that influence predation risk (e.g., concealment and visibility) across landscapes can be challenging. Traditional ground-based measures of predation risk are location specific and limited in spatial resolution. We demonstrate the benefits of terrestrial laser scanning (TLS) to map the properties of vegetation structure that shape fearscapes. We used TLS data to estimate the concealment of prey from multiple vantage points, representing predator sightlines, as well as the visibility of potential predators from the …
Effects Of Leaf Excision And Sample Storage Methods On Spectral Reflectance By Foliage Of Giant Reed, Arundo Donax, Kenneth R. Summy, Jonathan Lieman, Yuridia Patricia Gandy, Adarsh Mamachen, Ashish Mamachen, John A. Goolsby, Patricia J. Moran
Effects Of Leaf Excision And Sample Storage Methods On Spectral Reflectance By Foliage Of Giant Reed, Arundo Donax, Kenneth R. Summy, Jonathan Lieman, Yuridia Patricia Gandy, Adarsh Mamachen, Ashish Mamachen, John A. Goolsby, Patricia J. Moran
Biology Faculty Publications and Presentations
Research was conducted to evaluate the effects of leaf excision and sample storage methods on spectral reflectance by foliage of giant reed, Arundo donax, an invasive weed which has caused extensive damage in many areas of the Rio Grande Basin in Texas and Mexico. Within 24 hours of excision, A. donax leaves exposed to ambient laboratory conditions (room temperature under natural lighting conditions) exhibited two trends indicative of physiological stress: 1) small but significant increases in reflectance of blue and red wavelengths (400-500 nm and 600-700 nm, respectively) and 2) a substantial reduction in reflectance of near-infrared (NIR) wavelengths (700-1,100 …
Techniques To Facilitate The Acquisition Of Accurate Spectral Measurements And Multispectral Imagery Of Plant Foliage Under Artificial Lighting Conditions, Yuridia Patricia Gandy, Ashish Mamachen, Adarsh Mamachen, Jonathan Lieman, Michael W. Persans, Jason Parsons, Elamin E. Ibrahim, James H. Everitt, Christopher R. Little, Kenneth R. Summy
Techniques To Facilitate The Acquisition Of Accurate Spectral Measurements And Multispectral Imagery Of Plant Foliage Under Artificial Lighting Conditions, Yuridia Patricia Gandy, Ashish Mamachen, Adarsh Mamachen, Jonathan Lieman, Michael W. Persans, Jason Parsons, Elamin E. Ibrahim, James H. Everitt, Christopher R. Little, Kenneth R. Summy
Biology Faculty Publications and Presentations
Spectral measurements obtained in the laboratory under artificial lighting sources have been used for many years to develop spectral ‘libraries’ for various soil types, rocks and minerals, and other inanimate features occurring on or near the earth’s surface. Quartz halogen lamps have been shown to emit all of the electromagnetic (EMR) wavelengths required for the acquisition of quality multispectral imagery, and various techniques have been developed to facilitate the acquisition of accurate spectral measurements using such artificial lighting sources. Our objectives in this study were to evaluate the several factors of critical importance in obtaining accurate spectral measurements for plant …
Use Of Archive Aerial Photography For Monitoring Black Mangrove Populations, James H. Everitt, C. Yang, Frank W. Judd, Kenneth R. Summy
Use Of Archive Aerial Photography For Monitoring Black Mangrove Populations, James H. Everitt, C. Yang, Frank W. Judd, Kenneth R. Summy
Biology Faculty Publications and Presentations
A study was conducted on the South Texas Gulf Coast to evaluate archive aerial color-infrared (CIR) photography combined with supervised image analysis techniques to quantify changes in black mangrove [Avicennia germinans (L.) L.] populations over a 26-year period. Archive CIR film from two study sites (sites 1 and 2) was studied. Photographs of site 1 from 1976,1988, and 2002 showed that black mangrove populations made up 16.2%, 21.1%, and 29.4% of the study site, respectively. Photographs of site 2 from 1976 and 2002 showed that black mangrove populations made up 0.4% and 2.7% of the study site, respectively. Over the …
Detection Of Incipient Pest Infestations On Glasshouse Crops Using Multispectral Imagery And A Common Vegetation Index, Kenneth R. Summy, Christopher R. Little, James H. Everitt, Ruben A. Mazariegos, J. V. French, Mamoudou Setamou, Jesus Mata
Detection Of Incipient Pest Infestations On Glasshouse Crops Using Multispectral Imagery And A Common Vegetation Index, Kenneth R. Summy, Christopher R. Little, James H. Everitt, Ruben A. Mazariegos, J. V. French, Mamoudou Setamou, Jesus Mata
Biology Faculty Publications and Presentations
Research was conducted to evaluate the effectiveness of multispectral (conventional color and color infrared) imagery and a common vegetation index (simple ratio) for detecting incipient infestations of spider mites (Tetranychus spp.; Acari: Tetranychidae) and false spider mites (Brevipalpus spp.; Acari: Tenupalpidae) on selected crops under glasshouse conditions. Although damaging infestations of both mite species were associated with intense feeding injury which was readily detectable by visual inspection, subtle levels of foliar damage caused by the two mite species were difficult to detect by visual inspection and were not readily distinguishable from undamaged (healthy) foliage in conventional color (CC) or color …