Eric Graham

Tracking the rhythm of the seasons in the face of global change: phenological research in the 21st century

Phenology is the study of recurring life-cycle events, classic examples being the flowering of plants and animal migration. Phenological responses are increasingly relevant for addressing applied environmental issues. Yet, challenges remain with respect to spanning scales of observation, integrating observations across taxa, and modeling phenological sequences to enable ecological forecasts in light of future climate change. Recent advances that are helping to address these questions include refined landscape-scale phenology estimates from satellite data, advanced, instrument-based approaches for field measurements, and new cyberinfrastructure for archiving and distribution of products. These breakthroughs are improving our understanding in diverse areas, including modeling land-surface exchange, evaluating climate–phenology relationships, and making land-management decisions.

The future of citizen science: emerging technologies and shifting paradigms

Citizen science creates a nexus between science and education that, when coupled with emerging technologies, expands the frontiers of ecological research and public engagement. Using representative technologies and other examples, we examine the future of citizen science in terms of its research processes, program and participant cultures, and scientific communities. Future citizen-science projects will likely be influenced by sociocultural issues related to new technologies and will continue to face practical programmatic challenges. We foresee networked, open science and the use of online computer/video gaming as important tools to engage non-traditional audiences, and offer recommendations to help prepare project managers for impending challenges. A more formalized citizen-science enterprise, complete with networked organizations, associations, journals, and cyberinfrastructure, will advance scientific research, including ecology, and further public education.

Environmental sensor networks in ecological research

Environmental sensor networks offer a powerful combination of distributed sensing capacity, real-time data visualization and analysis, and integration with adjacent networks and remote sensing data streams. These advances have become a reality as a combined result of the continuing miniaturization of electronics, the availability of large data storage and computational capacity, and the pervasive connectivity of the Internet. Environmental sensor networks have been established and large new networks are planned for monitoring multiple habitats at many different scales. Projects range in spatial scale from continental systems designed to measure global change and environmental stability to those involved with the monitoring of only a few meters of forest edge in fragmented landscapes. Temporal measurements have ranged from the evaluation of sunfleck dynamics at scales of seconds, to daily CO2 fluxes, to decadal shifts in temperatures. Above-ground sensor systems are partnered with subsurface soil measurement networks for physical and biological activity, together with aquatic and riparian sensor networks to measure groundwater fluxes and nutrient dynamics. More recently, complex sensors, such as networked digital cameras and microphones, as well as newly emerging sensors, are being integrated into sensor networks for hierarchical methods of sensing that promise a further understanding of our ecological systems by revealing previously unobservable phenomena.

Tansley Review: Environmental sensor networks in ecological research

Environmental sensor networks offer a powerful combination of distributed sensing capacity, real-time data visualization and analysis, and integration with adjacent networks and remote sensing data streams. These advances have become a reality as a combined result of the continuing miniaturization of electronics, the availability of large data storage and computational capacity, and the pervasive connectivity of the Internet. Environmental sensor networks have been established and large new networks are planned for monitoring multiple habitats at many different scales. Projects range in spatial scale from continental systems designed to measure global change and environmental stability to those involved with the monitoring of only a few meters of forest edge in fragmented landscapes. Temporal measurements have ranged from the evaluation of sunfleck dynamics at scales of seconds, to daily CO2 fluxes, to decadal shifts in temperatures. Above-ground sensor systems are partnered with subsurface soil measurement networks for physical and biological activity, together with aquatic and riparian sensor networks to measure groundwater fluxes and nutrient dynamics. More recently, complex sensors, such as networked digital cameras and microphones, as well as newly emerging sensors, are being integrated into sensor networks for hierarchical methods of sensing that promise a further understanding of our ecological systems by revealing previously unobservable phenomena.

Influence of rocks on soil temperature, soil water potential, and rooting patterns for desert succulents

SummaryAt a site in the Sonoran Desert, subterranean rocks and exposed boulders affected soil water potential as well as root morphology and distribution. For Agave deserti, the number of lateral roots per unit length of main root was 11 times higher under rocks and six times higher alongside rocks than in rock-free regions. Total root length per unit soil volume for Echinocereus engelmannii averaged 3-fold higher within 1 cm of boulders than 5 cm away, where the soil was drier. The total length of lateral roots per unit length of main root for Ferocactus acanthodes was 4.2 m m−1 under rocks but only 0.8 m m−1 in rock-free regions. The number of lateral roots per unit length of main root for Opuntia acanthocarpa was 7-fold higher alongside rocks than in rock-free regions and even higher under rocks. For transplanted and watered A. deserti, the number of new main roots produced per 1–2 month interval averaged 13 for five plants on the north side of boulders, 8 on the south side, 11 for five plants with half of their roots under rocks, 2 for those with half of their roots over rocks, and 3 for the control plants without rocks. Laboratory experiments showed that the soil water potential under rocks for 10 and 30 mm waterings stayed above −0.5 MPa for 13 and 19 d longer, respectively, than for regions away from rocks. The shortwave absorptance of granitic rocks from the field site was 0.82, the thermal conductivity coefficient was 1.50 W m−1 °C−1, and the volumetric heat capacity was 1.75 MJ m−3 °C−1. Field measurements indicated that 5-cm-thick buried rocks decreased the diel variation in soil temperatures on their undersurface by only 0.4° C compared with soil. Thus, the primary influence of rocks at the field site on root proliferation and branching for the four species was apparently caused by influences on soil water content.

Drought tolerance associated with vertical stratification of two co-occurring epiphytic bromeliads in a tropical dry forest

Vertical stratification of epiphytes generally has not been reported for dry forests. For two epiphytic Crassulacean acid metabolism bromeliads that segregate vertically, it was hypothesized that different potentials for photoprotection or shade tolerance rather than drought tolerance is responsible for the observed stratification. The light environment, capacity for photoprotection, germination response to light quality, and responses to light and drought were thus examined for Tillandsia brachycaulos and T. elongata. Vertical and light-environment distributions differed for the two species but photoprotection and photodamage did not where they occurred at similar field locations; T. brachycaulos had a higher pigment acclimation to light. Tillandsia brachycaulos had higher acid accumulation under low light as opposed to T. elongata, which responded similarly to all but the highest light treatment. Tillandsia brachycaulos maintained positive total daily net CO(2) uptake through 30 d of drought; T. elongata had a total daily net CO(2) loss after 7 d of drought. The vertical stratification was most likely the result of the sensitivity to drought of T. elongata rather than differences in photoprotection or shade tolerance between the two species. Tillandsia elongata occurs in more exposed locations, which may be advantageous for rainfall interception and dew formation.

Use of a Networked Digital Camera to Estimate Net CO2 Uptake of a Desiccation-Tolerant Moss

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 CO2 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 CO2 uptake was linearly related to the green:red ratio of laboratory images when net CO2 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 CO2 m−2, 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.

Soil Sensor Technology: Life within a Pixel

ABSTRACT Soil organisms undertake every major ecosystem process, from primary production to decomposition to carbon sequestration, and those processes they catalyze have a bearing on the management of issues from agriculture to global climate change. Nonetheless, until recently, research to measure the dynamics of microscopic organisms living belowground has largely been limited to infrequent field sampling and laboratory extrapolation. Now, however, new sensor technologies can measure and monitor soil organisms and processes at rapid and continuous temporal scales. In this article, we describe these technologies and how they can be arrayed for an integrated view of soil dynamics.

Enhancing Motivation in a Mobile Participatory Sensing Project through Gaming

Bud Burst Mobile is a smart phone application for an environmental Participatory Sensing project that focuses on observing plants and collecting plant life stage data. The app was initially designed for record-keeping and motivation to participate in this project has been based on improving scientific knowledge. To test other methods for motivating data collection and increasing user retention, we added an outdoor game activity, similar to geocaching, called flora caching. Players gain points and levels within the game by finding and making qualitative observations on plants. Location-based information is included in the game with the display of local lists of plant species occurring in a users area derived from governmental data sources. Additionally, user-collected data and the occurrence of species on the local lists obtained from the photo-sharing website Flickr are displayed on an interactive map. Administrator targeting of individual plants facilitates expert control over crowd-sourced data collection for species of interest. We evaluated these additional features with the help of 50 volunteers playing on the UCLA campus as a case study. Results indicated that participants were highly motivated by the flora caching game, and next-most by the knowledge that environmental scientists will use the data collected for studying the effects of global climate change. Other motivating features included sharing plant observations with other users and the information contained in the local lists of plants.

Microhabitats, Germination, and Establishment for Mammillaria gaumeri (Cactaceae), a Rare Species from Yucatan

Mammillaria gaumeri is a rare cactus endemic to northern Yucatan that has a low rate of seedling establishment. We evaluated the effect of different light microhabitats on germination and seedling survival for this species in the field. Microclimatic requirements for seed germination are synchronized with those typical of the rainy season: germination was optimal at a soil water potential of −0.2 to 0.0 MPa and at a diurnal/nocturnal temperature of 30°/20°C. Low photon fluxes are necessary for seed germination; maximal germination ( \documentclass{aastex} \usepackage{amsbsy} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{bm} \usepackage{mathrsfs} \usepackage{pifont} \usepackage{stmaryrd} \usepackage{textcomp} \usepackage{portland,xspace} \usepackage{amsmath,amsxtra} \usepackage[OT2,OT1]{fontenc} \newcommand\cyr{ \renewcommand\rmdefault{wncyr} \renewcommand\sfdefault{wncyss} \renewcommand\encodingdefault{OT2} \normalfont \selectfont} \DeclareTextFontCommand{\textcyr}{\cyr} \pagestyle{empty} \DeclareMathSizes{10}{9}{7}{6} \begin{document} \landscape