Christopher R Hakkenberg

Christopher R Hakkenberg
Northern Arizona University | NAU · School of Informatics, Computing, and Cyber Systems

PhD

About

34
Publications
13,463
Reads
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291
Citations
Additional affiliations
May 2014 - July 2014
University of North Carolina at Chapel Hill
Position
  • Instructor
Description
  • GEOG 112: Environmental Conservation

Publications

Publications (34)
Article
Full-text available
Aim Empirical biodiversity – forest structure relationships (BSRs) underlie the use of forest structure as a remotely sensible proxy of biodiversity. However, little is known about how BSRs generalize to continental scales or how climate interacts with structure to drive local patterns in plant diversity. Resolving these research gaps in macrosyste...
Article
Full-text available
The goal of elucidating the primary mechanisms constraining the assembly and distribution of biodiversity remains among the central unresolved challenges facing the field of ecology. Simulation studies and experimental manipulations have focused on how patterns in community assembly result from bivariate relationships along productivity or environm...
Article
Full-text available
The community–continuum concept subsumes two contrasting yet complementary approaches to characterizing ecological communities (i.e., species assemblages) that simultaneously embrace communities as distinct and repeatable units while recognizing the continuous nature of their compositional variation. While both terms reference physical entities pop...
Article
Full-text available
Urbanization results in increasing impervious surfaces with the potential to threaten fragile environments and heighten flood risks. In the United States, research on the social processes driving urbanization has tended to focus on the twenty-first century, but less is known about how temporal trends arose from the spatial layout of the urban land...
Article
Full-text available
In light of the need to operationalize the mapping of forest composition at landscape scales, this study uses multi-scale nested vegetation sampling in conjunction with LiDAR-hyperspectral remotely-sensed data from the G-LiHT airborne sensor to map vascular plant compositional turnover in a compositionally- and structurally-complex North Carolina P...
Article
Full-text available
Spatially continuous canopy height is a vital input for modeling forest structures and functioning. The global ecosystem dynamics investigation (GEDI) waveform can penetrate a canopy to precisely find the ground and measure canopy height, but it is spatially discontinuous over the earth's surface. A common method to achieve wall-to-wall canopy heig...
Article
Full-text available
This article is composed of three independent commentaries about the state of Integrated, Coordinated, Open, Networked (ICON) principles in the American Geophysical Union Biogeosciences section, and discussion on the opportunities and challenges of adopting them. Each commentary focuses on a different topic: (a) Global collaboration, technology tra...
Article
Full-text available
Plants track changing climate partly by shifting their phenology, the timing of recurring biological events. It is unknown whether these observed phenological shifts are sufficient to keep pace with rapid climate changes. Phenological mismatch, or the desynchronization between the timing of critical phenological events, has long been hypothesized b...
Article
As one of the most dynamic aspects of global environmental change, land cover change (LCC) has a profound impact on terrestrial carbon sequestration. However, LCC-induced carbon fluxes are still the most uncertain terms in global and regional carbon budgets. Ecosystem gross primary production (GPP) is the total carbon uptake by vegetation through p...
Article
Full-text available
Understanding spatial patterns of diversity in tropical forests is indispensable for their sustainable use and conservation. Recent studies have reported relationships between forest structure and α-diversity. While tree α-diversity is difficult to map via remote sensing, large-scale forest structure models are becoming more common, which would fac...
Article
Full-text available
National Academies' Decadal Survey, Thriving on Our Changing Planet, recommended Surface Biology and Geology (SBG) as a "Designated Targeted Observable" (DO). The SBG DO is based on the need for capabilities to acquire global, high spatial resolution, visible to shortwave infrared (VSWIR; 380-2500 nm; ~30 m pixel resolution) hyperspectral (imaging...
Article
Full-text available
Urbanization results in increasing impervious surfaces with the potential to threaten fragile environments and heighten flood risks. In the United States, research on the social processes driving urbanization has tended to focus on the twenty-first century, but less is known about how temporal trends arose from the spatial layout of developed land...
Article
Full-text available
The characterization of fine temporal-resolution land surface dynamics from broadband optical satellite sensors is constrained by sparse acquisitions of high-quality imagery; interscene variation in radiometric, phenological, atmospheric, and illumination conditions; and subpixel variability in heterogeneous environments. In this letter, we address...
Article
Full-text available
In 2017, Hurricane Harvey caused substantial loss of life and property in the swiftly urbanizing region of Houston, TX. Now in its wake, researchers are tasked with investigating how to plan for and mitigate the impact of similar events in the future, despite expectations of increased storm intensity and frequency as well as accelerating urbanizati...
Article
Land-Cover/Land-Use (LCLU) change is a critical aspect of global environmental change, with profound social and ecological consequences. The southeastern U.S. in particular is changing rapidly, but a long-term, consistent LCLU history at fine spatial resolution does not exist for the region. Here, we present a new LCLU history of the southeastern U...
Article
Full-text available
The central role of floristic diversity in maintaining habitat integrity and ecosystem function has propelled efforts to map and monitor its distribution across forest landscapes. While biodiversity studies have traditionally relied largely on ground-based observations, the immensity of the task of generating accurate, repeatable, and spatially-con...
Code
The automatic adaptive signature generalization (AASG) algorithm overcomes many of the limitations associated with classification of multitemporal imagery. By locating stable sites between two images and using them to adapt class spectral signatures from a high-quality reference classification to a new image, AASG mitigates the impacts of radiometr...
Chapter
Full-text available
An ecological community refers to the association or assemblage of living organisms that coexist within a given space-time context. The dual concept of “community/continuum” refers to two complementary approaches to characterizing community types. The community-unit hypothesis describes ecological communities as distinct and repeatable entities, wh...
Chapter
Full-text available
Forests are declining across the globe due primarily to the overutilization of forest resources, particularly in developing countries. China, the world's largest developing country, is no exception. After the establishment of the People's Republic of China in 1949, it experienced a severe decline in forest resources, eventually leading to devastati...
Article
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Classifying land cover is perhaps the most common application of remote sensing, yet classification at frequent temporal intervals remains a challenging task due to radiometric differences among scenes, time and budget constraints, and semantic differences among class definitions from different dates. The automatic adaptive signature generalization...
Article
Full-text available
Can forest structure significantly predict tree species diversity in the forests of the North Carolina Piedmont? If so, which structural attributes are most correlated with it, and how effective are they when used in concert in a generalized predictive model of tree species diversity? North Carolina Piedmont, USA. Using a set of geographically dist...
Chapter
Full-text available
Vegetation is the primary producer in the terrestrial ecosystem. Vegetation absorbs the energy of electromagnetic radiation from the Sun and converts it to the energy that consumers in the ecosystem can use. As a result, vegetation is the foundation for nearly all the goods and services that terrestrial ecosystems provide to humanity. The advent of...
Conference Paper
Full-text available
Background/Question/Methods In addition to its renown for high levels of biodiversity and endemism, the region of NW Yunnan China is likewise a focal area for China’s national reforestation strategies. The Natural Forest Protection Program (NFPP) is prominent among these restoration efforts as one of the world’s largest reforestation and aforesta...
Conference Paper
Background/Question/Methods Recent research suggests that examination of functional and phylogenetic diversity will yield insight into processes shaping ecological communities. However, the type of data used to assess these patterns may influence the resulting conclusions. We investigated geographic variation in functional and phylogenetic diversi...
Article
Full-text available
Biodiversity conservation strategies around the world have been criticized when the goals of international organizations clash with the needs and traditions of local people. While the characterization of global conservation initiatives as a clash between scientifically-informed environmental policies and indigenous knowledge may retain discursive v...

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Project (1)
Project
The Houston-Galveston metropolitan area has experienced extraordinary growth over the past two decades. While census data provides a unique insight into the nature of that growth, its sparse temporal frequency limits its application for assessing fine-grained change. This study takes a different approach to quantifying how the greater Houston area is changing, agnostic to ground sampled data on development and population growth. Instead, this research leverages over twenty years of satellite observation to synoptically characterize the spatio-temporal dynamics of land cover change on an annual basis from 1997-2017. Driven by a demand for spatio-temporal accuracy and consistency, we employ 262 Landsat images across three space-borne observation platforms to classify land cover change using a three-part algorithmic procedure: automated training data selection of NLCD cover using Automatic Adaptive Signature Generalization (AASG), random forests image classification, and a series of spatio-temporal filters, which allow for an annual, spectrally-based classification of the NLCD’s Developed - Open class, otherwise classified using non-spectral, decadal, ancillary data. The classification time series is validated using accuracy comparison with NLCD products from 2001, 2006, and 2011, as well as independent high resolution satellite data from Ikonos, Quickbird, and Worldview sensors . Results include detailed change maps, conversion time series, uncertainty maps, and a categorization of urbanization morphologies in the Houston area. In addition to its methodological innovations in the field of remote sensing, these results confirm that extraordinary scale of urbanization in Houston, especially in floodplains and ecologically sensitive areas. https://chrishakkenberg.wixsite.com/home/featured-projects