Prairie Dogs – is science being hijacked?

1. South Platte Park... a Natural Area Skot Latona, SkotL@sspr.org Supervisor of S Platte Park 303-730-1022  www.sspr.org/nature  3000 W Carson Dr. Littleton, CO 80120 Prairie Dogs – is science being hijacked?

2. Objectives and Origin

4. Pdogs – What good are they? • Really Good • Good For Nuthin’

5. Messages in the Media

6. Fact Sheet: The black-tailed prairie dog is a "keystone" species in the short- and mixed-grass prairie ecosystems, which has been documented extensively by biologists. A South Dakota study found 134 vertebrate species associated with prairie dog towns, while a Montana study found 163 prairie dog "associates," or species likely to be dependent on prairie dogs.

7. A common misconception, however, is that over 100 species may be associated with prairie dogs.  Many prairie dog advocate groups often claim that more than 100 species benefit from prairie dogs or the habitat they create and maintain.  This number is presumably derived from a journal article, which provided a list of 163 species that had been sighted on prairie dog colonies.  This list, however, included 17 waterfowl, 14 shorebirds, and several exotics, as well as domestic horses, sheep, and cattle.  It is misleading to imply that these species are dependent upon or in any way benefit from prairie dogs or the habitat they create and maintain, simply because they were sighted near the colony during an observation period.

8. Rozol is an effective tool that landowners, ranchers and custom applicators can use to manage infestations of black-tailed prairie dogs, a range rodent that consumes up to two pounds of vegetation every week. An active prairie dog colony can cut grazing capacity by over 50%, requiring ranchers to allocate up to 40 acres per steer, whereas uninfested rangeland can often carry a steer on only 10 acres. Pastures with 20% prairie dog occupancy reduced the estimated value of livestock weight gain by over $14 per steer, while 60% occupancy reduced that value by $37 or more per steer. Rozol is an effective tool that landowners, ranchers and custom applicators can use to manage infestations of black-tailed prairie dogs, a range rodent that consumes up to two pounds of vegetation every week. An active prairie dog colony can cut grazing capacity by over 50%, requiring ranchers to allocate up to 40 acres per steer, whereas uninfested rangeland can often carry a steer on only 10 acres. Pastures with 20% prairie dog occupancy reduced the estimated value of livestock weight gain by over $14 per steer, while 60% occupancy reduced that value by $37 or more per steer

9. Scientific Source Material

11. Scientists Argue • Ecological Review of BT Pdogs and Associated Spp in W. South Dakota – Sharps/Uresk • The Prairie Dog and Biotic Diversity – Miller/Ceballos/Reading • A Reevaluation of the Role of Prairie Dogs – Stapp • Role of Pdogs as a Keystone Species – Miller et al.

12. A Day in the Life . . .

13. Prairie Dogs Ecological Functions • Fill bellies of predators, scavengers, parasites • Burrow • Cut plants – grazing vs clipping

14. Prairie Dogs Ecological Results • Support predator, scavenger, parasite populations • Create nest sites and refuge • Alter moisture regimes • Soil compaction/aeration • Alter plant species composition and abundance • Alter invertebrate composition and abundance

15. Prairie Dogs Ecological Role

16. Defining Dependence A Critical Review of Assumptions About Pdogs- Kotliar • Obligate • Facultative Dependence (Strong, Weak) • Associate (opportunistic, accidental, alien)

17. Defining Keystone • Paine 1969 – activities greatly modify species composition and physical appearance – it determines the integrity of the community and its unaltered persistance. • Power and others, 1996 – has a large overall effect on community structure or function and effect is disproportionately large relative to its abundance.

18. Answering Our Questions

19. How Many Species ARE dependant on Prairie Dogs? • 1 is obligate dependent • 2 have strong facultative dependence • 6 dependent, but only in 1 of 4 criteria • 5 associate with higher abundance • 5 associate with no change in abundance • 10 associate with lower abundance • 117 have natural life histories that indicate they could use prairie dogs or their effects • 10 are domestic species • 52 appear to be accidental encounters

20. Are they a keystone species? • 9 species would decline or disappear at local or landscape scale, thus diminishing biological diversity across the landscape It is not necessary to believe they have 208 associated species to conclude they affect community integrity. • They are not the only agents of disturbance, but the scale they operate at is unique for the landscape, thus important to ecosystem integrity and persistence. While the magnitude was sometimes overstated in the literature, it does meet the dfinition.

21. Are they a keystone species? • Extent of effects is limited on landscape scale, but so many varied affects above that of other species – fulfill more than one function thus overall large impact. • high density, long deep burrows usable by other species is unparalleled • concentrated herbivory, reluctance to emigrate means more long-term change in veg composition than any other herbivore • Create significant fire breaks that affect the behavior and role of fire • Mix topsoil and subsoil, redistribute nutrients, promote moisture penetration, increase moisture retention, reduce flashflooding • Increased moisture attracts grazing presence, affects nutritional component of plants • Alter species composition, alter nigtrogen concentrations, reduce biomass and transpiration • Pdogs have a ‘per capita’ impact that matches or exceeds impacts of the other herbivores thus exceeds impact vs relative abundance.

22. Has Anyone Attempted a Web of Life?

23. Return to media messages • Humane Society Fact Sheet – • while a Montana study found 163 prairie dog "associates," or species likely to be dependent on prairie dogs • Ecological Services discussion – • It is misleading to imply that these species are dependent upon or in any way benefit from prairie dogs or the habitat they create and maintain, simply because they were sighted near the colony during an observation period. • Rozol Advertising • How valid is the study and what does it really show?

24. Final question about Prairie Dogs: • Should it matter in how they are managed?

25. As an educator, what can you do to: • Keep up on science? • Find sources can you trust? • Demand validity to science in media and marketing? • Protect the integrity of science? • Promote inquiry learning, environmental literacy, and critical analysis by students?