Use of a Networked Digital Camera to Estimate Net CO₂Uptake of a Desiccation‐Tolerant Moss

Abstract

Simple visible-light digital cameras offer a potential for expanded forms of plant ecological research. The moss Tortula princeps undergoes changes in reflected visible light during cycles of drying and hydrating in the field, and the MossCam project has collected digital images of T. princeps at least daily since 2003. Laboratory studies can be used to calibrate these images to indicate field physiological conditions. Drying the moss 6 d in the laboratory resulted in a decrease of net CO 2 uptake to near 0; recovery after rewetting occurred within 10 min. The difference in reflectance between hydrated and dry T. princeps was maximal ca. 550 nm, and maximal net CO 2 uptake was linearly related to the green : red ratio of laboratory images when net CO 2 uptake was positive. Using the green : red ratio of field images and otherwise assuming ideal conditions, the total carbon gain for a 6-d period around a 1.3-mm rain event was ca. 208 mmol CO 2 m ÿ2 , equivalent to 69 d of respiration under dry conditions. Using a visible-light digital camera with micrometeorological data and laboratory-based gas exchange measurements, T. princeps can be used as a model species for simple field estimations of photosynthesis, carbon gain, and phenological events.

Using digital time-lapse cameras to monitor species-specific understorey and overstorey phenology in support of wildlife habitat assessment

“…The increasing popularity and use of inexpensive visible spectrum digital cameras in recent years offers the potential to remotely monitor and measure phenological events (Graham et al 2006(Graham et al , 2010Bradley et al 2010). Repeat photography allows sampling at very dense temporal resolutions, often at daily or hourly intervals, for monitoring vegetation phenology.…”

“…For example, Purcell (2000) utilised digital cameras to detect changes in wheat and soybean canopies at a 1-m spatial resolution over a growing season. Graham et al (2006) acquired daily images of mosses during drying and moistening cycles to develop a comprehensive understanding of the changing status of the species under different climatic conditions. Richardson et al (2007) recently mounted a commercially available digital web camera system on a CO 2 flux tower in Barlett, New Hampshire, to observe deciduous vegetation green-up and to make comparisons to changes in the fraction of the photosynthetically active radiation absorbed by the canopy.…”

New Approaches in Embedded Networked Sensing for Terrestrial Ecological Observatories

“…One class of strategic tools for assessing global vegetation responses is remote sensing using either satellite or aircraft multispectral (Moulin et al, 1996) and hyperspectral imagers (Ustin et al, 2004). In a similar way, ground-based remote sensing using portable digital cameras and reflectivity scanners for spectral analysis and optical measurements offers tremendous potential to complement and validate wide-area remote sensing classifications (Graham et al, 2006;Chen and Welch, 2002;Treitz and Howarth, 1999;Holland et al, 1997) and yield fine-scale information about microsites, physiology, and morphology that is impossible to measure from aircraft or satellites.…”

“…We have also installed a number of similar networked digital cameras throughout the James Reserve, ranging from fixed field-of-view cameras used to observe the physiologic status of plants and tower-based robotic pan/tilt/zoom (PTZ) cameras to track periodic plant growth changes (phenology) and wildlife activity to PTZ cameras mounted on the underside of two NIMS robots to map fine-scale and temporally dynamic attributes of vegetation, soil, insects, and environmental conditions beneath the instrument transects. These small, versatile RGB color digital cameras have been successfully calibrated to quantify changes in leaf surface area in woody and herbaceous perennials and to assess spectrally the photosynthetic activity and annual net uptake of carbon as a function of rainfall fluctuations in a desiccation-tolerant species of moss (Graham et al, 2006;Mishler and Hamilton, 2002). Further studies to automate and extrapolate comparable measurements (spectrum and surface area) from hundreds to thousands of concurrently collected images via the tower cams and NIMS cams may provide a reliable and efficient methodology for scaling changes in small features to surface reflectance signatures that are detectable by satellite and airborne sensors.…”

EcoIP: An open source image analysis toolkit to identify different stages of plant phenology for multiple species with pan–tilt–zoom cameras

“…The recent expansion of imaging hardware, such as portable and Internet-connected visible light digital cameras, coupled with methods such as repeat photography and digital image processing, provide the means for detecting a wide range of scales of plant phenology, from mosses (Graham et al, 2006) to forests (Richardson et al, 2007). Indeed, visible-light digital cameras are becoming commonplace in research for quantitatively describing vegetation (Crimmins and Crimmins, 2008).…”