Devan McGranahan

Dr. Devan McGranahan

USDA Agricultural Research Service, Miles City, Montana, USA
orcid

Research Focus & Metrics

Academic Career Length

22Years (2005-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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1 September 2016 in Soil Science Society of America Journal
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Journal Article
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RTResham Thapa
Resham Thapa
ACAmitava Chatterjee
Amitava Chatterjee
RARakesh Awale
Rakesh Awale
Devan McGranahanDevan McGranahan
Devan McGranahan
ADAaron Lee M. Daigh
Aaron Lee M. Daigh

14 April 2017
Verified
Book Chapter
Open access
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SFSamuel D. Fuhlendorf
Samuel D. Fuhlendorf
RFRichard W. S. Fynn
Richard W. S. Fynn
Devan McGranahanDevan McGranahan
Devan McGranahan
DTDirac Twidwell
Dirac Twidwell
Rangeland management, like most disciplines of natural resource management, has been characterized by human efforts to reduce variability and increase predictability in natural systems (steady-state management often applied through a command-and-control paradigm). Examples of applications of traditional command and control in natural resource management include wildfire suppression, fences to control large ungulate movements, predator elimination programs, and watershed engineering for flood control and irrigation. Recently, a robust theoretical foundation has been developed that focuses on our understanding of the importance of variability in nature. This understanding is built upon the concept of heterogeneity, which originated from influential calls to consider spatial and temporal scaling in ecological research. Understanding rangeland ecosystems from a resilience perspective where we recognize that these systems are highly variable in space and time cannot be achieved without a focus on heterogeneity across multiple scales. We highlight the broad importance of heterogeneity to rangelands and focus more specifically on (1) animal populations and production, (2) fire behavior and management, and (3) biodiversity and ecosystem function. Rangelands are complex, dynamic, and depend on the variability that humans often attempt to control to ensure long-term productivity and ecosystem health. We present an ecological perspective that targets variation in rangeland properties—including multiple ecosystem services—as an alternative to the myopic focus on maximizing agricultural output, which may expose managers to greater risk. Globally, rangeland science indicates that heterogeneity and diversity increase stability in ecosystem properties from fine to broad spatial scales and through time.

27 July 2012 in Biodiversity and Conservation
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Journal Article
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RMRaymond A. Moranz
Raymond A. Moranz
DDDiane Debinski
Diane Debinski
Devan McGranahanDevan McGranahan
Devan McGranahan
DEDavid M. Engle
David M. Engle
JMJames R. Miller
James R. Miller

2 July 2012 in Journal of Applied Ecology
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Journal Article
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Devan McGranahanDevan McGranahan
Devan McGranahan
DEDavid M. Engle
David M. Engle
SFSamuel D. Fuhlendorf
Samuel D. Fuhlendorf
SWStephen J. Winter
Stephen J. Winter
JMJames R. Miller
James R. Miller
DDDiane Debinski
Diane Debinski

1 December 2011 in Ecosphere
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Journal Article
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DDDiane Debinski
Diane Debinski
RMRaymond A. Moranz
Raymond A. Moranz
JDJohn T. Delaney
John T. Delaney
JMJames R. Miller
James R. Miller
DEDavid M. Engle
David M. Engle
MGMolly K. Gillespie
Molly K. Gillespie
Many species of plants and animals associated with grasslands are rare or declining due to habitat loss and degradation. Although grassland plants and insects evolved in the context of both grazing a...

7 May 2018 in Ecology and Evolution
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Journal Article
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Devan McGranahanDevan McGranahan
Devan McGranahan
BGBenjamin Geaumont
Benjamin Geaumont
Jonathan SpiessJonathan Spiess
Jonathan Spiess
Ecologists have used Global Positioning Systems (GPS) to track animals for 30 years. Issues today include logging frequency and precision in estimating space use and travel distances, as well as battery life and cost. We developed a low‐cost (~US$125), open‐source GPS datalogger based on Arduino. To test the system, we collected positions at 20‐s intervals for several 1‐week durations from cattle and sheep on rangeland in North Dakota. We tested two questions of broad interest to ecologists who use GPS collars to track animal movements: (1) How closely do collared animals cluster in their herd? (2) How well do different logging patterns estimate patch occupancy and total daily distance traveled? Tested logging patterns included regular logging (one position every 5 or 10 min), and burst logging (positions recorded at 20‐s intervals for 5 or 10 min per hour followed by a sleep period). Collared sheep within the same pasture spent 75% of daytime periods within 51 m of each other (mean = 42 m); collared cattle were within 111 m (mean = 76 m). In our comparison of how well different logging patterns estimate space use versus constant logging, the proportion of positions recorded in 1‐ and 16‐ha patches differed by 2%–3% for burst logging and 1% for regular logging. Although all logging patterns underestimated total daily distance traveled, underestimations were corrected by multiplying estimations by regression coefficients estimated by maximum likelihood. Burst logging can extend battery life by a factor of 7. We conclude that a minimum of two collars programmed with burst logging robustly estimate patch use and spatial distribution of grazing livestock herds. Research questions that require accurately estimating travel of individual animals, however, are probably best addressed with regular logging intervals and will thus have greater battery demands than spatial occupancy questions across all GPS datalogger systems.