Using WebGIS to Develop a Spatial Bibliography for Organizing, Mapping, and Disseminating Research Information: A Case Study of Quaking Aspen

On the Ground • Spatial data is valuable to researchers for locating studies that occur in a particular area of interest, or one with similar attributes. • Without a standard in publishing protocol, spatial data largely goes unreported, or is difficult to find without searching the publication. • Assigning location data and displaying points on a public web map makes locating publications based on spatial location possible

Remotely Sensed Canopy Nitrogen Correlates With Nitrous Oxide Emissions in a Lowland Tropical Rainforest

Tropical forests exhibit significant heterogeneity in plant functional and chemical traits that may contribute to spatial patterns of key soil biogeochemical processes, such as carbon storage and greenhouse gas emissions. Although tropical forests are the largest ecosystem source of nitrous oxide (N2O), drivers of spatial patterns within forests are poorly resolved. Here, we show that local variation in canopy foliar N, mapped by remote‐sensing image spectroscopy, correlates with patterns of soil N2O emission from a lowland tropical rainforest. We identified ten 0.25 ha plots (assemblages of 40–70 individual trees) in which average remotely‐sensed canopy N fell above or below the regional mean. The plots were located on a single minimally‐dissected terrace (km2) where soil type, vegetation structure and climatic conditions were relatively constant. We measured N2O fluxes monthly for 1 yr and found that high canopy N species assemblages had on average three‐fold higher total mean N2O fluxes than nearby lower canopy N areas. These differences are consistent with strong differences in litter stoichiometry, nitrification rates and soil nitrate concentrations. Canopy N status was also associated with microbial community characteristics: lower canopy N plots had two‐fold greater soil fungal to bacterial ratios and a significantly lower abundance of ammonia‐oxidizing archaea, although genes associated with denitrification (nirS, nirK, nosZ) showed no relationship with N2O flux. Overall, landscape emissions from this ecosystem are at the lowest end of the spectrum reported for tropical forests, consist with multiple metrics indicating that these highly productive forests retain N tightly and have low plant‐available losses. These data point to connections between canopy and soil processes that have largely been overlooked as a driver of denitrification. Defining relationships between remotely‐sensed plant traits and soil processes offers the chance to map these processes at large scales, potentially increasing our ability to predict N2O emissions in heterogeneous landscapes

Episodic Canopy Structural Transformations and Biological Invasion in a Hawaiian Forest

The remaining native forests on the Hawaiian Islands have been recognized as threatened by changing climate, increasing insect outbreak, new deadly pathogens, and growing populations of canopy structure-altering invasive species. The objective of this study was to assess long-term, net changes to upper canopy structure in sub-montane forests on the eastern slope of Mauna Kea volcano, Hawai‘i, in the context of continuing climate events, insect outbreaks, and biological invasion. We used high-resolution multi-temporal Light Detection and Ranging (LiDAR) data to quantify near-decadal net changes in forest canopy height and gap distributions at a critical transition between alien invaded lowland and native sub-montane forest at the end of a recent drought and host-specific insect (Scotorythra paludicola) outbreak. We found that sub-montane forests have experienced a net loss in average canopy height, and therefore structure and aboveground carbon stock. Additionally, where invasive alien tree species co-dominate with native trees, the upper canopy structure became more homogeneous. Tracking the loss of forest canopy height and spatial variation with airborne LiDAR is a cost-effective way to monitor forest canopy health, and to track and quantify ecological impacts of invasive species through space and time

Great Basin Bristlecone Pine (Pinus longaeva) Historic Fire Regimes and Future Fire Risk: A Multi-Scale Assessment

Great Basin bristlecone pine (Pinus longaeva: GBBP) is an iconic species found in montane habitats of the Great Basin and Colorado Plateau – a region in which wild fire severity and size have increased over the past 30 years. Study objectives were to use multiple lines of evidence to – 1) reconstruct historic fire regime patterns across a range of sites, 2) quantify conifer succession on GBBP sites after stand-replacing fire and 3) assess GBBP wild re-related risk under contemporary and future environmental conditions. Results from 10 sites reveal that historical fires in GBBP were typically small and of mixed-severity, with moderate to long re-free intervals. Initial post-fire conifer recruitment for three fires was relatively rapid with GBBP dominant to subdominant. Large size and high severity of recent fires in GBBP habitats suggest that contemporary and future re risk may exceed historical conditions resulting in GBBP range contractions and possible localized extinctions

Great Basin Bristlecone Pine (Pinus longaeva) Stand Composition and Structure: Variability Reveals Flexibility in Life-history Strategy

Great Basin bristlecone pine (Pinus longaeva: GBBP) is known for its longevity and slow growth. We hypothesize that this conservative life-history strategy is adaptive for individual survival and stand persistence across a range of biophysical conditions. We documented non-riparian GBBP from 1980 to 3535 m above sea level as single- species stands, and in mixed stands of two to seven species (total of 12 tree associates). Species diversity varied by elevation and ecoregion. In 69 representative plots, total tree and GBBP-only density varied from 60-2068 and 15-818/ha, respectively; and was not correlated with elevation. Stand and GBBP basal area varied from 2.7- 220.9 and 0.1-206.6 m2/ha, with highest levels restricted to high-elevation, GBBP-dominated stands. Mean age estimates (from a subset of plot trees) were 233 years for all plot trees and 322 years for GBBP only. Results reveal high stand compositional and structural variability across the elevational and geographic range, suggesting substantial adaptive flexibility

Data from: Environmental controls on canopy foliar N distributions in a neotropical lowland forest

Distributions of foliar nutrients across forest canopies can give insight into their plant functional diversity and improve our understanding of biogeochemical cycling. We used airborne remote sensing and Partial Least Squares Regression (PLSR) to quantify canopy foliar nitrogen (N) across ~164 km2 of wet lowland tropical forest in the Osa Peninsula, Costa Rica. We determined the relative influence of climate and topography on the observed patterns of canopy foliar N using a gradient boosting model (GBM) technique. At a local scale, where climate and substrate where constant, we explored the influence of slope position on canopy N by quantifying canopy N on remnant terraces, their adjacent slopes and knife edged ridges. In addition, we climbed and sampled 540 trees and analyzed foliar N in order to quantify the role of species identity (phylogeny) and environmental factors in predicting canopy N. Observed canopy N heterogeneity reflected environmental factors working at multiple spatial scales. Across the larger landscape, elevation and precipitation had the highest relative influence on predicting canopy foliar N (30 and 24%), followed by soils (15%), site exposure (9%), compound topographic index (8%), substrate (6%), and landscape dissection (6%). Phylogeny explained ~75% of the variation in the filed collected foliar N data, suggesting that phylogeny largely underpins the response to the environmental factors. Taken together, these data suggest that a large fraction of the variance in canopy N across the landscape is proximately driven by species composition, though ultimately this is likely a response to abiotic factors such as climate and topography. Future work should focus on the mechanisms and feedbacks involved, and how shifts in climate may translate to changes in forest function

Soil biomarkers of cacao tree cultivation in the sacred cacao groves of the northern Maya lowlands

•The Ancient Maya tended sacred groves of cacao trees.•The shade, moisture and humidity of karst sinkholes supported cacao cultivation.•Hot water extraction of soil allows the quantitation of cacao biomarkers: Theobromine; theophylline; and caffeine.•Formal staircases, altars, grinding stones, and sherds of incense pots are associated with the sacred groves. The importance of cacao in ancient Mesoamerica is attested by the presence of cacao biomarkers in ritual pottery. By at least the Postclassic period, if not earlier, cacao beans are thought to have been a prominent mode of currency in the central Yucatan. During the colonial period the Maya of Yucatan were tending sacred groves of cacao trees in the shaded, humid microclimates of karst sinkholes that dot the peninsula. We report on the development of a method for the extraction and quantitation of the methylxanthine biomarkers of cacao (theobromine, theophylline, and caffeine) from soil. The presence of these biomarkers provides evidence of the distribution and ritual importance of these sacred cacao groves to the Maya. Methylxanthine biomarkers were present in the soils of nine of eleven sampled sinkholes in Yucatan and Quintana Roo, MX

Osa Peninsula, Costa Rica foliar nitrogen (%)

Field collected foliar nitrogen (%) from mature canopy leaves see Balzotti et al. (2016) Environmental Controls on Canopy Foliar N Distributions in a Neotropical Lowland Forest. Ecological Applications and Asner, G. P., & Martin, R. E. (2016). Convergent elevation trends in canopy chemical traits of tropical forests. Global Change Biology. 22, 2216-2227, doi: 10.1111/gcb.1316