Systems analysis and simulation of tick-cattle-landscape interactions in south Texas /
Each year since their official eradication from the United States in 1943, the cattle-tick species Boophilus microplus and Boophilus annulatus have penetrated a quarantine zone established along the Texas-Mexico border designed to exclude them. Inspection and quarantine procedures have eradicated r...
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| Format: | Thesis Book |
| Language: | English |
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[Place of publication not identified] :
[publisher not identified] ;
2000.
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| Online Access: | http://proxy.library.tamu.edu/login?url=http://proquest.umi.com/pqdweb?did=727852861&sid=1&Fmt=2&clientId=2945&RQT=309&VName=PQD |
| Summary: | Each year since their official eradication from the United States in 1943, the cattle-tick species Boophilus microplus and Boophilus annulatus have penetrated a quarantine zone established along the Texas-Mexico border designed to exclude them. Inspection and quarantine procedures have eradicated reinfestations successfully within the U.S., but increasing acaricide resistance in Mexican Boophilus populations poses a threat to future control. Improved understanding of the influence of and relationship among Boophilus populations, their bovine hosts, and vegetation in south Texas could improve prediction of the behavior of reintroduced Boophilus populations and increase management options. To this end I constructed a simulation model to evaluate how microclimate, habitat heterogeneity, and cattle movement may influence dynamics of Boophilus ticks in south Texas. I compared results of this model with one built at a coarser scale to evaluate how estimated influence of these factors may change with the level of detail of the model. Sensitivity analyses suggested that population dynamics received the most influence from habitat type and microclimate, followed by host movement, the importance of which increased with increasing habitat heterogeneity. Fecundity of female ticks and degree of on-host mortality also had large effects. When used to simulate laboratory experiments from the literature, the fine-scale model usually predicted observed results well, except for egg mortality and larval longevity at low environmental temperatures. The coarse-scale model appeared less sensitive to habitat type, microclimate, and host movement. Use of the fine-scale model to predict Boophilus-population dynamics in a hypothetical south-Texas pasture showed that the model reasonably generated qualitative patterns of stages in the life-history of Boophilus populations, though it tended to overestimate population sizes. For answering questions regarding microclimate, habitat heterogeneity, and host movement, a finer-scale model seems more appropriate, as it allows representation of this system with greater spatial resolution and incorporation of historic temperature and relative-humidity data. Such a model can aid decision making by predicting Boophilus-population responses to specific weather patterns and habitat heterogeneity. |
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| Item Description: | Vita. "Major Subject: Wildlife and Fisheries Sciences". |
| Physical Description: | xv, 178 leaves : illustrations, maps ; 28 cm. Issued also on microfiche from University Microfilm Inc. |
| Bibliography: | Includes bibliographical references (leaves 159-176). |