Vegetation Patterns of the Tallgrass Prairie: A Proposal

1. Vegetation Patterns of the Tallgrass Prairie: A Proposal Daniel McGlinn Map courtesy of PG Earls

2. McGlinn 2005 Outline • Introduction • The Species pool hypothesis and turnover • The Tallgrass Prairie Preserve • Management methods and goals • Species-area and species-time theory • Preliminary analyses: diversity through space and time • Future Questions

3. McGlinn 2005 Speciation large-scale migration small-scale migration dispersal Filtering Actual species pool Local species pool Regional species pool Species pool hypothesis Abiotic factors and Biotic interactions Redrawn from Zobel 1997

4. McGlinn 2005 Development of Species-pool hypothesis • Importance of regional species pool • Zobel 1997 • Evolutionary or historic soil conditions determine local species richness (SR) • Pärtel 2002 and Ewald 2003 • Exotics may provide key insight • Palmer 2003

5. McGlinn 2005 Field of Dreams hypothesis • Special case of Species-pool hypothesis • Palmer et al. 1997 • If you build it (disturbance regime), they will come… • Evolutionary pattern of burning and grazing • Predicts an increase in natives and a decrease in abundance and richness of exotics

6. McGlinn 2005 Speciation large-scale migration small-scale migration dispersal Filtering Actual species pool Local species pool Regional species pool Species pool hypothesis Abiotic factors and Biotic interactions Redrawn from Zobel 1997

7. McGlinn 2005 Turnover • Species level • Carousel model: van der Maarel & Sykes 1997 • Mobility indices: Palmer and Rusch 2001 • Community level • Species-area curve: Watson 1859 • Species-time curve: Preston 1960

8. McGlinn 2005 Community level turnover • Species-area and species-time relationships • Preston’s (1960) ergodicconjecture – Rosenzweig 1995,1998 • Tested for time-space interaction – Adler and Lauenroth (2003) • Sampling and ecological effects – White (2004)

9. McGlinn 2005 The Tallgrass PrairiePreserve • 15,000-hectare natural area • Owned by TNC since 1989 • Bison introduced 1993 • Randomized burning regime began 1993 • Ecological goal: • To create a heterogeneous landscape that contains the full compliment of native species

10. McGlinn 2005 Current data • UTM grid 1997-2000 • 20 quadrats resampled 1998-2004 • Plots chosen randomly with criteria that it not have any woody cover, standing water, or >20% rock cover

11. McGlinn 2005 10 m Map courtesy of PG Earls

12. McGlinn 2005 Randomized Burning • Simulate the presettlement fire frequency and seasonality • Burn units selected randomly from areas with a minimum fuel load • Creates aspatially and temporally dynamic landscape

13. McGlinn 2005 Species-area and Species-time • Structure of the equation • c, z, and w values • Empirical results • linearity and nonlinearity • Mechanisms drive patterns • Statistical, ecological, evolutionary

14. McGlinn 2005 Structure of SAR • c and z values; • c is often only interpreted as a mere intercept • Non-linear form of SAR shows that c actually helps to determine the slope

15. McGlinn 2005 Structure of STR • Same as SAR • Rate of species accumulation is w

16. McGlinn 2005 Empirical curves from the TGPP Fig from Palmer et al. (2003) z = 0.30 Log # Species Log Area

17. McGlinn 2005 Empirical patterns Rosenzweig 1995

18. McGlinn 2005 TGPP quadrat scale Preston 1960

19. McGlinn 2005 Current findings • Species richness has significantly increased in the twenty 10x10 plots from 1998 to 2004 • SAR is slightly convex in log-log space • STR more linear in log-log space • The rate of species-accumulation decreases at the same rate for increasing area and increasing time

20. McGlinn 2005

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22. McGlinn 2005 Mean r2 = 0.9816

23. McGlinn 2005 Mean r2 = 0.9982

24. McGlinn 2005 z w log A log T Decreasing rate of species accumulation Slopes of species-area curves Slopes of species-time curves

25. McGlinn 2005

26. McGlinn 2005 Remaining questions • Continue to resample plots • When does ecological change begin to take place • How does fire and grazing effect the shape of this relationship • At what scale do spatial and temporal accumulation of species seem equivalent? • Is this the same as for Konza (47 m2)? • Is the way that organisms move from one location to another analogous to their ‘movement’ through time?

27. McGlinn 2005 Questions

28. McGlinn 2005 Other explanations abound… • Exotics maintain or increase • A more heterogeneous landscape structurally provides more niches • Exotics are inherently generalists and can adapt rapidly to new environments – highly plastic phenotypes