Evaluation of a forage allocation model for Theodore Roosevelt National Park.
Abstract: We developed a forage allocation model using a deterministic, linear optimization module in a commercially available spreadsheet package to help resource managers in Theodore Roosevelt National Park (TRNP), North Dakota determine optimum numbers of four ungulate species, bison (Bison bison), elk (Cervus elaphus), mule deer (Odocoileus hemionus), and feral horses, in the Park. TRNP staff actively managed bison, elk, and feral horse numbers within bounds suggested by our model from 1983 to 1996. During this period, we measured vegetation at 8 grassland and 12 wooded sites at 1-3 year intervals to determine if model solutions were appropriate for maintaining stable conditions in important plant communities in the Park. The data we recorded at these sites indicated minimal change in plant communities from 1983 to 1996. Changes in most vegetation categories that we expected when animal numbers exceeded model optimums for short periods (decreases in coverage/stem numbers of palatable plant species, increases in bare ground or unpalatable plant species) did not occur consistently under high or low precipitation conditions. The lack of sensitivity of our model to decreases in overall production of palatable plant species that occurred due to drought, fire, expansion of black-tailed prairie dog (Cynomys ludovicianus) colonies, and the spread of leafy spurge (Euphorbia esula) in areas of the Park where we did not have monitoring sites suggested that the model under-estimated the total number of ungulates that the Park could support. Management for population levels of ungulates defined by the model probably led to over protection of common plant communities and insufficient protection of rare plant communities. Detecting changes in rare plant communities could have been accomplished by re-designing our vegetation monitoring program, but changing emphasis to protection of rare plants would have likely promoted under use of grazing-tolerant habitat types, dissatisfaction in tourists visiting the Park to see large mammals, and large increases in cost and intrusiveness of management activities such as fencing and control of ungulate populations. The model was a flawed representation of grazing dynamics in TRNP, but we believe it succeeded in making management personnel aware of the biological constraints they face when making management decisions.
Publication Date: 2002-05-09 PubMed ID: 11995238DOI: 10.1006/jema.2001.0514Google Scholar: Lookup
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- Journal Article
- Research Support
- Non-U.S. Gov't
- Research Support
- U.S. Gov't
- Non-P.H.S.
Summary
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The research article is about the development and testing of a forage allocation model to manage four ungulate species in Theodore Roosevelt National Park, North Dakota. The main aim was to determine optimum numbers of these species for maintaining stable conditions in the park’s plant communities.
Development and Application of the Model
- The researchers developed a forage allocation model using a deterministic, linear optimization module in a commercially available spreadsheet package. The model aimed to help park resource managers determine optimal population counts for four ungulate species [bison (Bison bison), elk (Cervus elaphus), mule deer (Odocoileus hemionus), and feral horses]] in Theodore Roosevelt National Park (TRNP).
- Park staff managed the number of bison, elk, and feral horses between 1983 and 1996 following the recommendations proposed by the model.
Evaluation of Vegetation and Model’s Effectiveness
- During the application of the model, the researchers measured the vegetation in different sites at varying intervals. This was to establish if the management based on the model’s solutions was maintaining stable plant community conditions.
- The measurements indicated minimal changes in the plant communities from 1983 to 1996, which meant the model’s suggested optimum animal numbers were somewhat effective.
- However, there were some anomalies. Changes in vegetation, which the researchers expected under high or low precipitation conditions when animal numbers exceeded the model’s optima, did not consistently occur.
- Also, the model appeared insensitive to decreases in the overall production of edible plant species due to external factors such as drought, fire, and the spread of certain species.
Implications and Limitations of the Model
- These findings suggested that the model might have underestimated the total number of ungulates the Park could support. Following its recommendations might have caused overprotection of common plant communities and insufficient protection for rare ones.
- While a redesign of the vegetation monitoring program could have improved detection of changes in rare plant communities, it could also have led to under-use of grazing-tolerant habitats, tourist dissatisfaction, and an increase in the cost and intrusiveness of management activities.
See the Bigger Picture
- In conclusion, while the model had limitations and may have been a flawed representation of grazing dynamics in TRNP, it was effective in making park management aware of the biological constraints they face when making management decisions.
Cite This Article
APA
Irby LR, Norland JE, Westfall JA, Sullivan MA.
(2002).
Evaluation of a forage allocation model for Theodore Roosevelt National Park.
J Environ Manage, 64(2), 153-169.
https://doi.org/10.1006/jema.2001.0514 Publication
Researcher Affiliations
- Ecology Department, Montana State University, Bozeman, Montana 59717, USA. ubili@montana.edu
MeSH Terms
- Animals
- Bison
- Conservation of Natural Resources
- Deer
- Environmental Monitoring
- Feeding Behavior
- Female
- Horses
- Male
- Models, Theoretical
- Plants, Edible
- Population Dynamics
Citations
This article has been cited 3 times.- Davies G, McCann B, Sturdevant J, Swenson F, Ovchinnikov IV. Isotopic paleoecology of Northern Great Plains bison during the Holocene. Sci Rep 2019 Nov 12;9(1):16637.
- Amor JM, Newman R, Jensen WF, Rundquist BC, Walter WD, Boulanger JR. Seasonal home ranges and habitat selection of three elk (Cervus elaphus) herds in North Dakota. PLoS One 2019;14(2):e0211650.
- Baker DL, Powers JG, Ransom JI, McCann BE, Oehler MW, Bruemmer JE, Galloway NL, Eckery DC, Nett TM. Reimmunization increases contraceptive effectiveness of gonadotropin-releasing hormone vaccine (GonaCon-Equine) in free-ranging horses (Equus caballus): Limitations and side effects. PLoS One 2018;13(7):e0201570.
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