Plant seed dispersal by two frugivorous Amazonian fish

1. Southern Illinois University Carbondale Fisheries & Illinois Aquaculture Center Plant seed dispersal by two frugivorous Amazonian fish F. Chu-Koo C. Kohler, W.Camargo, F. Alcántara & L. Rodríguez CRSP- IIAP-SIUC

2. Funding for this research was provided by thePond Dynamics/Aquaculture Collaborative Research Support Program(PD/A CRSP) The PD/A CRSP is funded in part by USAID and by participating institutions.

3. Seed dispersal in tropical forests Wind (Anemocory) Water (Hydrocory) Animals (Zoocory) • Animals: • Monkeys • Bats • Birds • Terrestrial mammals

4. Recently, turtles and fish were included as potential plant seed dispersers However, researchers studies have been based almost entirely on circumstantial evidence

5. According to Goulding (1980), fish swim into the flooded forest and feed on ± 200 fruits and seeds as these ‘reproductive products’ fall into the water These fish may disperse a variety of seeds along the Amazon Basin and therefore their conservation is extremely important

6. Main goals of the Study: 1) Determine seed dispersal potential by 2 migratory frugivorous fish from the Amazon region 2) Determine effect of fish digestive system over germination rate of ingested seeds 3) Assess effect of fish size over germination rate of ingested seeds

7. MATERIAL AND METHODS Study Site: Instituto de Investigaciones de la Amazonía Peruana-IIAP. Iquitos (Northeast of Peru) Duration: From June 2002 to February 2003

8. Photo by Maria Luiza Delgado Assad Piaractus brachypomus Colossoma macropomum Family: CHARACIDAE Family: CHARACIDAE Common names: Gamitana (Peru), Cachama negra (Colombia), Cachama (Venezuela), Tambaqui (Brazil) and Black-finned Pacu (USA) Common names: Paco (Peru), Morocotó (Venezuela) Cachama blanca (Colombia), Pirapitinga (Brazil) and Red-belly Pacu (USA)

9. SEEDS STUDIED • Pseudobombax munguba “punga” • Family Bombacaceae

10. 2. Hevea brasiliensis “shiringa” Family Euphorbiaceae

11. 3. Bactris gasipaes “pijuayo”, “pejibaye” Family Arecaceae

12. 4. Psidium guajaba “guayaba”, “guava” Family Myrtaceae

13. 5. Piranhea trifoliata “sardina caspi” Family Euphorbiaceae

14. 6. Strychnos erichsonii “Tocón huayo” Family Loganiaceae

15. 7. Bactris concinna “ñejilla” Family Arecaceae

16. 8. Myrciaria dubia “camu-camu” Family Myrtaceae Photo courtesy of Ms. Leslie Taylorof Raintree Nutrition, Inc.

17. Experimental Design Objective 1: To assess if these fish species can actually be seed dispersers in nature • Step 1. Fish were placed randomly into 6 m3 cages • Step 2. Fish were starved during 48 h, to allow digestive system clean up • Step 3. Fish were fed until satiation

18. Experimental Design - Cont • Step 4. After verifying fruit or seed consumption, fishes were placed into individual tanks to collect their feces

19. Experimental Design - Cont • Step 5. Entire seeds collected from fish feces were sowed into sterilized humus

20. Experimental Design - Cont • Step 6. Germination of digested and undigested seeds were verified • Step 7. Germination rate for digested and undigested seeds were calculated for each treatment

21. Experimental Design - Cont Objective 2: To assess if ichthyocory enhances seeds germination rate. Treatment 1(Ichthyocory): Seeds collected from fish feces were sowed in sterilized humus Treatment 2 (Anemocory): Seeds collected from fruits were left exposed for 2 days to local environmental conditions and then sowed to simulate dispersion by the wind Treatment 3 (Hydrocory): Seeds collected from fruits were placed in the water (hanging in the cages) for 2 days and then sowed to simulate dispersion by water

22. Experimental Design - Cont Objective 3: To assess if fish size does enhance germination rate of ingested seeds Fishes were divided in 3 different groups: Group 1: Three fish < 1 kg Group 2: Three fish 1 to 3 kg Group 3: Three fish > 5 kg

23. RESULTS AND DISCUSSION Do these seeds germinate after being ingested by fish? Can these fish species be seed dispersers in the Amazon floodplain areas?

24. RESULTS AND DISCUSSION Table 1. Potential of seeds to be dispersed by C. macropomum and P. brachypomus Seeds Colossoma Piaractus Seed tested size Psidium guajaba Yes Yes 2.5 mm P. munguba Yes --- 3.5 mm Piranhea trifoliata --- No* 7.0 mm Myrciaria dubia Yes Yes 10.0 mm Strychnos erichsonii --- Yes 14.0 mm Hevea brasiliensis No* No* 15.0 mm Bactris concinna No* --- 15.0 mm Bactris gasipaes No* --- 20.0 mm * Tritured seeds

25. RESULTS AND DISCUSSION Is ichthyocory really important? Does fish digestive system enhance seed germination?

26. RESULTS AND DISCUSSION Table 2. Seed germination rates (%) from 5 fruit species obtained from paco (P. brachypomus), gamitana (Colossoma macropomum) and compared with wet and dried seeds (α= 0.05) Germination rate observed Fruits offered Seed size Paco Gamitana Hydrocory Anemocory P-Value Decision Guava 2.5 mm 32.11 42.67 38.01 15.71 0.4245 N.S. Punga 3.5 mm --- 79.65 56.92 40.88 <0.001 H.S Sardina caspi 7.0 mm 38.03 --- 71.66 30.00 0.0018 H.S Camu-camu 10.0 mm 78.66 90.89 74.58 41.99 <0.001 H.S Tocón-huayo 14.0 mm 39.60 --- 41.47 55.52 0.0869 N.S Shiringa, Ñejilla and Pijuayo did not germinate (broken seeds)

27. RESULTS AND DISCUSSION Does fish size enhance the germination rate of ingested seeds?

28. RESULTS AND DISCUSSION Table 3. Seed germination rates (%) from 5 fruit species fed to paco (Piaractus brachypomus) and 6 fruit species fed to gamitana (Colossoma macropomum) at three different weight groups (α= 0.05) Paco (germination rate) Gamitana (germination rate) Fruits offered Seed size 1kg 3kg +5kg P-Value 1kg 3kg +5kg P-Value Guava 2.5 mm 34.8 32.6 SB 0.6980 49.4 54.2 50.7 0.6503 Punga 3.5 mm -- -- -- --- 81.7 75.3 82.7 0.2672 Sardina caspi 7.0 mm BS 32.0 50.0 0.8220 -- -- -- --- Camu-camu 10.0 mm BS 75.0 75.0 0.9543 90.3 77.3 94.3 0.4369 Tocón-huayo 14.0 mm 36.3 56.2 BS 0.2762 -- -- -- --- Shiringa (15.0 mm), Ñejilla (15.0 mm) and Pijuayo (20.0 mm) did not germinate (broken seeds)

29. CONCLUSIONS • In Colossoma macropomum: • Only three out 6 seeds (punga, camu-camu and guava) might be likely dispersed by this fish sp. • Shiringa, ñejilla and pijuayo seeds could not germinate probably because of their size (>15mm) and hardness which obligate fish to break down before ingesting them • Punga and camu-camu seeds after passing throughout fish digestive system proved to have better viability than seeds supposedly dispersed by water and wind (P<0.001) • Fish weight (size) did not have a significant effect on seed germination rate (guava P=0.6980, sardina caspi P=0.822, camu-camu P=0.9543 and tocón-huayo P=0.2762)

30. CONCLUSIONS- P. brachypomus • Four out 5 seeds (coto-huayo, camu-camu, sardina caspi, and guava) may be dispersed by this fish • Like in Colossoma shiringa seeds might not be dispersed by P. brachypomus probably because of their size and hardness • Fish size does not have a significant effect on germination rate (Guava P=0.6980, Sardina caspi P=0.822, Camu-camu P=0.9543 and Tocón huayo P=0.2762

31. FINAL CONCLUSION Our results demonstrate that both frugivorous are active seed dispersing agents and they likely play an important role disseminating seeds in the flooded Amazon forest

32. Thank You, any questions? Pictures credits: Instituto de Investigaciones de la Amazonía Peruana Sociedade Civil Mamirahua/CNPq/Rainforest Alliance Carlos Araujo-Lima and Michael Goulding Dr. Fernando Alcántara (IIAP) Blgo. Luciano Rodríguez (IIAP) www.peru.com Others

33. Piaractus brachypomus “Paco” (Peru), “Morocoto” (Venezuela) and “Pirapitinga” (Brazil) • Camu-camu • Tamara • Guava • Punga • Shiringa • Pijuayo • Hipururo

34. RESULTS AND DISCUSSION Fig. 5. One-way analysis for germination rate of tocón huayo seeds by groups

35. RESULTS AND DISCUSSION Fig. 1. One-way analysis for germination rate of camu-camu (Myrciaria dubia) seeds by groups

36. RESULTS AND DISCUSSION Fig. 2. One-way analysis for germination rate of guava (Psidium guajaba) seeds by groups

37. RESULTS AND DISCUSSION Fig. 3. One-way analysis for germination rate of punga (Pseudobombax munguba) seeds by groups

38. RESULTS AND DISCUSSION Fig. 4. One-way analysis for germination rate of sardina caspi (Piranhea trifoliata) seeds by groups