Interactive effects of Russian olive and the common carp on linked stream-riparian food webs

Transcription

1 Interactive effects of Russian olive and the common carp on linked stream-riparian food webs Kaleb K. Heinrich 1,2 and Colden V. Baxter 2 1 Department of Biology, University of Mary Hardin-Baylor, Belton, Texas 2 Department of Biological Sciences, Idaho State University, Pocatello, Idaho

2 Multiple invaders Biological invasions continue to increase Non-native, invasive species effects on other non-native species are lacking Multiple invaders maybe involved in a variety of complex interactions

3 Invasional meltdown hypothesis The process by which a group of nonindigenous species facilitate one another s invasion (Simberloff and Von Holle 1999)

4 Ecological Stoichiometry Nutrient recycling by a consumer depends on imbalance between its nutrient content and its food Invasive species effects via changes in nutrient stoichiometry has received little attention

5 Deep Creek International Biological Program (IBP) Site Deep Creek Dr. G. W. Minshall

6 Russian olive invasion Photo credit: G. W. Minshall

7 Russian olive invasion Minshall 1978 Bioscience

8 Russian olive invasion at Deep Creek

9 Deep Creek Russian olive cover ~3X increase

10 Reduces N limitation of stream primary producers Increases DON by 37%, increased load & export DeCant 2008

11 Increases litter inputs 25X Decomposes 35% slower than native litter Few native stream animals eat it ( mismatch ) 4X increase in benthic storage, then export ~15% decrease in ecosystem efficiency

12 Carp invasion Deep Creek

13 Carp increase subsequent Russian olive invasion F [1,12] = 7.82, P = 0.02 IACUC Protocol 707 ~4X increase in carp density Photo: C. V. Baxter

14 Carp consume and assimilate Russian olive On average, Russian olive made up ~40% of gut contents (n=63) ~1/3 of carp tissue derived from Russian olive (δ 13 C and δ 2 H analysis) Common carp pharyngeal teeth

15 Bioenergetic analysis of carp Demand: 1 Carp requires g AFDM/day (Huisman 1976, Lupatsch et al. 1998) 1200 g AFDM/day to sustain 70s population 3500 g AFDM/day to sustain current carp population Availability: g AFDM/day g AFDM/day (calculated from Mineau et al. 2012) 1970s

16 Bioenergetic analysis of carp Demand: 1 Carp requires g AFDM/day (Huisman 1976, Lupatsch et al. 1998) 1200 g AFDM/day to sustain 70s population 3500 g AFDM/day to sustain current carp population Availability: g AFDM/day g AFDM/day (calculated from Mineau et al. 2012)

17 Bioenergetic analysis of carp Demand: 1 Carp requires g AFDM/day (Huisman 1976, Lupatsch et al. 1998) 1200 g AFDM/day to sustain 70s population 3500 g AFDM/day to sustain current carp population Availability: g AFDM/day g AFDM/day (calculated from Mineau et al. 2012)

18 Bioenergetic analysis of carp Demand: 1 Carp requires g AFDM/day (Huisman 1976, Lupatsch et al. 1998) 1200 g AFDM/day to sustain 70s population 3500 g AFDM/day to sustain current carp population Availability: g AFDM/day g AFDM/day (calculated from Mineau et al. 2012)

19 Bioenergetic analysis of carp Demand: 1 Carp requires g AFDM/day (Huisman 1976, Lupatsch et al. 1998) 1200 g AFDM/day to sustain 70s population 3500 g AFDM/day to sustain current carp population Availability: g AFDM/day g AFDM/day (calculated from Mineau et al. 2012)

20 Carp exclusion experiment Carp exclusion (n=7) Control (n=7) Primary producer biomass, organic matter, macrophytes

21 Subsidized carp effects: F [1,12] = 6.91, P = 0.02

22 Subsidized carp effects: F [1,12] = 5.41, P = 0.04 F [1,12] = 5.52, P = 0.04

23 Carp excretion experiment Carp held in coolers NH 4, SRP, TDN, TDP, total N, and total P Comparison of carp with variable amounts of Russian olive in gut (Deep Creek) Compared with carp that do not consume Russian olive (Deep Creek vs. Portneuf River)

24 Subsidized carp effects: P = 0.008, F [1,18] = R 2 = 0.50, P < 0.001

25 Subsidized carp effects: N:P ratio of recycled material was higher for carp that consumed Russian olive F [1,18] = 8.85, P = 0.008

26 Consequences for nutrient dynamics?

27 Consequences for nutrient dynamics? Amplify the spiraling and export of N from streams?

28 Another dimension:

29 Large scale Russian olive removal Large scale carp manipulation

30 Photo credits: Hannah Harris

31 Summary Current carp population could not be supported without Russian olive inputs Subsidized carp are reducing chlorophyll-a, organic matter, and macrophytes Carp consuming RO are excreting more N

32 Multiple invasive species interact Consequences for aquatic-terrestrial ecosystem Understanding synergistic consequences of invaders, should inform adaptive management

33 Acknowledgements Dr. G. W. Minshall Dr. J. Hood & Dr. M. Mineau ISU Stream Ecology Center UMHB Science Education Resource Center Field and lab assistance: C. Baxter, T. Gardner, A. Bell, N. Tillotson, J. Cornell, M. Schenk, R. Blackadar, H. Harris, K. Behn, M. K. Ventura, D. Larson, M. Lyon, A. Eckersell, L. Denny, S. Collins, M. Mozneb, N. Nelson, M. Blackhorse, S. Hennings, E. Richins, D. Huber, R. Burrow, M. Heinrich, and A. Heinrich

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