Table 2. Taxonomic composition, frequency of occurrence (%) and mean abundance (in parentheses) of each zooplankton taxa in each environment influenced by the Salto Santiago and Salto Osório reservoirs.
| Taxa | S1 | S2 | S3 | S4 | S5 | S6 | S7 | S8 |
|---|---|---|---|---|---|---|---|---|
| Rotifera | ||||||||
| Ascomorpha sp. | 22 (246) | 17 (64) | 11 (11) | 20 (35) | 17 (24) | 20 (228) | 14 (77) | 16 (14) |
| Asplanchna sieboldii | 34 (3,313) | 38 (5,258) | 32 (1,943) | 31 (615) | 29 (141) | 30 (293) | 31 (1,211) | 27 (81) |
| Brachionus calyciflorus | 18 (404) | 11 (309) | 12 (427) | 11 (337) | 17 (101) | 14 (851) | 12 (602) | 18 (1,070) |
| Brachionus dolabratus | 9 (14) | 11 (82) | 16 (138) | 19 (26) | 14 (29) | 10 (19) | 12 (44) | 9 (21) |
| Brachionus falcatus | 14 (101) | 17 (34) | 19 (121) | 18 (32) | 21 (27) | 19 (50) | 16 (47) | 14 (39) |
| Collotheca sp. | 9 (17) | 9 (18) | 12 (46) | 10 (14) | 13 (28) | 9 (17) | 10 (172) | 10 (3) |
| Conochilus sp. | 64 (3,570) | 67 (6,448) | 67 (6,598) | 66 (1,918) | 58 (807) | 61 (3,129) | 59 (2,633) | 51 (1,210) |
| Euchlanis dilatata | 31 (881) | 46 (961) | 39 (677) | 48 (1,045) | 40 (855) | 27 (793) | 22 (671) | 14 (464) |
| Filinia opoliensis | 24 (707) | 24 (191) | 12 (88) | 20 (56) | 18 (89) | 11 (41) | 11 (32) | 10 (411) |
| Hexarthra sp. | 57 (1,864) | 62 (1,462) | 60 (3,002) | 57 (639) | 56 (794) | 49 (420) | 48 (798) | 28 (379) |
| Kellicottia bostoniensis | 67 (1,204) | 50 (1,097) | 49 (614) | 62 (713) | 67 (779) | 57 (958) | 38 (477) | 56 (1,134) |
| Keratella americana | 33 (107) | 31 (69) | 33 (66) | 34 (42) | 31 (35) | 31 (79) | 23 (29) | 27 (21) |
| Keratella cochlearis | 51 (1,717) | 51 (587) | 44 (176) | 46 (132) | 51 (215) | 39 (280) | 44 (177) | 38 (59) |
| Keratella tropica | 39 (596) | 27 (311) | 24 (136) | 19 (109) | 31 (470) | 23 (488) | 19 (215) | 14 (127) |
| Ploesoma truncatum | 36 (377) | 21 (673) | 17 (94) | 47 (184) | 42 (148) | 23 (52) | 20 (127) | 36 (140) |
| Polyarthra sp. | 82 (5,232) | 82 (5,859) | 70 (4,870) | 82 (1,992) | 74 (2,444) | 76 (3,583) | 79 (2,002) | 77 (1,042) |
| Ptygura sp. | 11 (82) | 10 (11) | 14 (245) | 16 (44) | 14 (35) | 11 (7) | 10 (11) | 14 (44) |
| Synchaeta sp. | 57 (1,925) | 52 (1,920) | 44 (1,080) | 34 (341) | 50 (751) | 44 (798) | 42 (578) | 36 (739) |
| Trichocerca cylindrica | 36 (441) | 44 (1,031) | 41 (708) | 54 (703) | 50 (594) | 31 (316) | 49 (698) | 44 (470) |
| Trichocerca similis | 14 (51) | 7 (62) | 8 (11) | 10 (14) | 12 (18) | 7 (35) | 7 (8) | 12 (9) |
| Cladocera | ||||||||
| Bosmina freyi | 20 (95) | 19 (303) | 21 (205) | 20 (125) | 21 (104) | 21 (279) | 18 (189) | 19 (52) |
| Bosmina hagmanni | 90 (3,703) | 98 (5,608) | 98 (7,256) | 94 (2,480) | 93 (2,828) | 93 (4,115) | 90 (3,172) | 92 (2,814) |
| Bosminopsis deitersi | 56 (876) | 38 (422) | 29 (116) | 24 (82) | 37 (118) | 29 (376) | 20 (61) | 21 (85) |
| Ceriodaphnia cornuta | 87 (5,255) | 92 (7,182) | 88 (6,138) | 92 (2,593) | 86 (3,590) | 81 (4,417) | 93 (5,854) | 86 (2,945) |
| Ceriodaphnia silvestrii | 74 (1,947) | 81 (3,734) | 83 (2,535) | 84 (2,203) | 82 (2,198) | 78 (1,780) | 79 (3,611) | 78 (2,249) |
| Daphnia gessneri | 76 (1,609) | 87 (2,498) | 83 (1,980) | 87 (889) | 86 (2,183) | 81 (1,605) | 84 (2,359) | 83 (3,770) |
| Diaphanosoma birgei | 12 (47) | 19 (216) | 21 (208) | 17 (41) | 9 (110) | 21 (86) | 20 (213) | 16 (41) |
| Diaphanosoma spinulosum | 59 (676) | 64 (1,402) | 69 (2,917) | 67 (782) | 58 (476) | 61 (1,266) | 69 (2,166) | 52 (1,382) |
| Moina minuta | 68 (2,903) | 72 (2,395) | 72 (2,703) | 64 (1,010) | 69 (2,086) | 63 (1,544) | 64 (2,309) | 59 (1,988) |
| Copepoda | ||||||||
| Nauplii Cyclopoida | 92 (12,376) | 91 (12,127) | 88 (9,239) | 89 (5,787) | 86 (4,589) | 90 (7,109) | 87 (6,868) | 94 (4,960) |
| Nauplii Calanoida | 99 (8,775) | 97 (9,091) | 93 (7,001) | 96 (3,018) | 92 (3,815) | 94 (6,064) | 96 (6,422) | 92 (4,061) |
| Copepodit Cyclopoida | 88 (2,566) | 83 (2,921) | 70 (2,665) | 77 (1,273) | 81 (2,057) | 69 (1,694) | 77 (1,549) | 78 (1,497) |
| Copepodit Calanoida | 97 (11,168) | 94 (10,107) | 97 (14,235) | 98 (6,762) | 99 (8,511) | 99 (12,681) | 100 (15,509) | 100 (11,281) |
| Acanthocyclops robustus | 18 (22) | 12 (14) | 12 (13) | 14 (9) | 17 (13) | 13 (13) | 10 (29) | 12 (4) |
| Argyrodiaptomus furcatus | 17 (81) | 13 (62) | 14 (47) | 10 (18) | 12 (28) | 14 (76) | 10 (45) | 12 (21) |
| Mesocyclops meridianus | 14 (59) | 16 (26) | 13 (15) | 18 (21) | 17 (16) | 16 (37) | 13 (65) | 13 (12) |
| Notodiaptomus henseni | 78 (1,630) | 80 (2,320) | 79 (2,086) | 82 (923) | 79 (926) | 80 (2,525) | 87 (2,969) | 76 (1,051) |
| Notodiaptomus iheringi | 21 (123) | 18 (122) | 14 (125) | 14 (63) | 16 (66) | 16 (101) | 27 (249) | 18 (67) |
| Notodiaptomus sp. | 7 (32) | 11 (17) | 11 (14) | 7 (9) | 9 (29) | 13 (45) | 13 (69) | 11 (15) |
| Notodiaptomus transitans | 50 (1,959) | 53 (5,151) | 48 (1,604) | 49 (1,060) | 49 (1,024) | 52 (2,447) | 57 (2,184) | 38 (1,016) |
| Thermocyclops decipiens | 60 (987) | 53 (620) | 57 (571) | 56 (391) | 60 (612) | 56 (340) | 54 (480) | 60 (331) |
| Thermocyclops minutus | 41 (337) | 37 (237) | 32 (155) | 41 (111) | 31 (217) | 32 (139) | 37 (99) | 29 (24) |
| Total richness | 82 | 76 | 76 | 80 | 86 | 85 | 81 | 88 |
Notes.
Environments: fluvial (S1 and S5), transitional (S2 and S6), lacustrine (S3 and S7), and downstream (S4 and S8). Rare species (≤10%) in the study are not included in the table.