Network


Latest external collaboration on country level. Dive into details by clicking on the dots.

Hotspot


Dive into the research topics where Amanda M. Schwantes is active.

Publication


Featured researches published by Amanda M. Schwantes.


Trends in Plant Science | 2015

Global satellite monitoring of climate-induced vegetation disturbances

Nate G. McDowell; Pieter S. A. Beck; Jeffrey Q. Chambers; Chandana Gangodagamage; Jeffrey A. Hicke; Cho-ying Huang; Robert E. Kennedy; Dan J. Krofcheck; Marcy E. Litvak; Arjan J. H. Meddens; Jordan Muss; Robinson I. Negrón-Juárez; Changhui Peng; Amanda M. Schwantes; Jennifer J. Swenson; Louis James Vernon; A. Park Williams; Chonggang Xu; Maosheng Zhao; Steven W. Running; Craig D. Allen

Terrestrial disturbances are accelerating globally, but their full impact is not quantified because we lack an adequate monitoring system. Remote sensing offers a means to quantify the frequency and extent of disturbances globally. Here, we review the current application of remote sensing to this problem and offer a framework for more systematic analysis in the future. We recommend that any proposed monitoring system should not only detect disturbances, but also be able to: identify the proximate cause(s); integrate a range of spatial scales; and, ideally, incorporate process models to explain the observed patterns and predicted trends in the future. Significant remaining challenges are tied to the ecology of disturbances. To meet these challenges, more effort is required to incorporate ecological principles and understanding into the assessments of disturbance worldwide.


Ecology | 2013

Soil nutrient availability and reproductive effort drive patterns in nutrient resorption in Pentaclethra macroloba

Katherine L. Tully; Tana E. Wood; Amanda M. Schwantes; Deborah Lawrence

The removal of nutrients from senescing tissues, nutrient resorption, is a key strategy for conserving nutrients in plants. However, our understanding of what drives patterns of nutrient resorption in tropical trees is limited. We examined the effects of nutrient sources (stand-level and tree-level soil fertility) and sinks (reproductive effort) on nitrogen (N) and phosphorus (P) resorption. We evaluated resorption efficiency (percentage of original nutrients removed during senescence) and resorption proficiency (indicated by senesced-leaf nutrient concentrations) in a symbiotic N-fixing tree species, Pentaclethra macroloba, common to tropical forests in Costa Rica. Although tree-level soil P alone did not drive patterns in nutrient resorption, P efficiency and proficiency declined with increasing tree-level soil P when reproductive status was also considered. Nutrient resorption declined with increasing tree-level soil P in trees that were actively fruiting or that experienced high seedfall the year prio...


Remote Sensing | 2018

Integrating Drone Imagery into High Resolution Satellite Remote Sensing Assessments of Estuarine Environments

Patrick C. Gray; Justin T. Ridge; Sarah K. Poulin; Alexander C. Seymour; Amanda M. Schwantes; Jennifer J. Swenson; David W. Johnston

Very high-resolution satellite imagery (≤5 m resolution) has become available on a spatial and temporal scale appropriate for dynamic wetland management and conservation across large areas. Estuarine wetlands have the potential to be mapped at a detailed habitat scale with a frequency that allows immediate monitoring after storms, in response to human disturbances, and in the face of sea-level rise. Yet mapping requires significant fieldwork to run modern classification algorithms and estuarine environments can be difficult to access and are environmentally sensitive. Recent advances in unoccupied aircraft systems (UAS, or drones), coupled with their increased availability, present a solution. UAS can cover a study site with ultra-high resolution (<5 cm) imagery allowing visual validation. In this study we used UAS imagery to assist training a Support Vector Machine to classify WorldView-3 and RapidEye satellite imagery of the Rachel Carson Reserve in North Carolina, USA. UAS and field-based accuracy assessments were employed for comparison across validation methods. We created and examined an array of indices and layers including texture, NDVI, and a LiDAR DEM. Our results demonstrate classification accuracy on par with previous extensive fieldwork campaigns (93% UAS and 93% field for WorldView-3; 92% UAS and 87% field for RapidEye). Examining change between 2004 and 2017, we found drastic shoreline change but general stability of emergent wetlands. Both WorldView-3 and RapidEye were found to be valuable sources of imagery for habitat classification with the main tradeoff being WorldView’s fine spatial resolution versus RapidEye’s temporal frequency. We conclude that UAS can be highly effective in training and validating satellite imagery.


New Phytologist | 2018

Accounting for landscape heterogeneity improves spatial predictions of tree vulnerability to drought

Amanda M. Schwantes; Anthony J. Parolari; Jennifer J. Swenson; Daniel M. Johnson; Jean-Christophe Domec; Robert B. Jackson; Norman Pelak; Amilcare Porporato

As climate change continues, forest vulnerability to droughts and heatwaves is increasing, but vulnerability varies regionally and locally through landscape position. Also, most models used in forecasting forest responses to heat and drought do not incorporate relevant spatial processes. In order to improve spatial predictions of tree vulnerability, we employed a nonlinear stochastic model of soil moisture dynamics accounting for landscape differences in aspect, topography and soils. Across a watershed in central Texas we modeled dynamic water stress for a dominant tree species, Juniperus ashei, and projected future dynamic water stress through the 21st century. Modeled dynamic water stress tracked spatial patterns of remotely sensed drought-induced canopy loss. Accuracy in predicting drought-impacted stands increased from 60%, accounting for spatially variable soil conditions, to 72% when also including lateral redistribution of water and radiation/temperature effects attributable to aspect. Our analysis also suggests that dynamic water stress will increase through the 21st century, with trees persisting at only selected microsites. Favorable microsites/refugia may exist across a landscape where trees can persist; however, if future droughts are too severe, the buffering capacity of an heterogeneous landscape could be overwhelmed. Incorporating spatial data will improve projections of future tree water stress and identification of potential resilient refugia.


Remote Sensing of Environment | 2016

Quantifying drought-induced tree mortality in the open canopy woodlands of central Texas

Amanda M. Schwantes; Jennifer J. Swenson; Robert B. Jackson


Plant Cell and Environment | 2018

Co-occurring woody species have diverse hydraulic strategies and mortality rates during an extreme drought: Belowground hydraulic failure during drought

Daniel M. Johnson; Jean-Christophe Domec; Z. Carter Berry; Amanda M. Schwantes; Katherine A. McCulloh; David R. Woodruff; H. Wayne Polley; Remí Wortemann; Jennifer J. Swenson; D. Scott Mackay; Nate G. McDowell; Robert B. Jackson


Global Change Biology | 2017

Measuring canopy loss and climatic thresholds from an extreme drought along a fivefold precipitation gradient across Texas

Amanda M. Schwantes; Jennifer J. Swenson; Mariano González-Roglich; Daniel M. Johnson; Jean-Christophe Domec; Robert B. Jackson


Environmental Research Letters | 2017

Trends in size of tropical deforestation events signal increasing dominance of industrial-scale drivers

Kemen G. Austin; Mariano González-Roglich; Danica Schaffer-Smith; Amanda M. Schwantes; Jennifer J. Swenson


Archive | 2018

Co-occurring woody species have diverse hydraulic strategies and mortality rates during an extreme drought.

Daniel M. Johnson; J-C Domec; Z. Carter Berry; Amanda M. Schwantes; Katherine A. McCulloh; Woodruff; H. Wayne Polley; Remí Wortemann; Jennifer J. Swenson; D. Scott Mackay; Nate G. McDowell; Robert B. Jackson


Environmental Research Letters | 2017

Erratum: Trends in size of tropical deforestation events signal increasing dominance of industrial-scale drivers (2017 Environ. Res. Lett. 5 054009)

Kemen G. Austin; Mariano González-Roglich; Danica Schaffer-Smith; Amanda M. Schwantes; Jennifer J. Swenson

Collaboration


Dive into the Amanda M. Schwantes's collaboration.

Top Co-Authors

Avatar
Top Co-Authors

Avatar
Top Co-Authors

Avatar
Top Co-Authors

Avatar

Nate G. McDowell

Pacific Northwest National Laboratory

View shared research outputs
Top Co-Authors

Avatar

Jean-Christophe Domec

Institut national de la recherche agronomique

View shared research outputs
Top Co-Authors

Avatar
Top Co-Authors

Avatar
Top Co-Authors

Avatar

H. Wayne Polley

Agricultural Research Service

View shared research outputs
Top Co-Authors

Avatar

Katherine A. McCulloh

University of Wisconsin-Madison

View shared research outputs
Researchain Logo
Decentralizing Knowledge