The Ecology of Tijuana Estuary, California: An Estuarine Profile

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F~gure 32 Brackish marsh hab~lats support large ernergents, tnclvd$ng bulrushes (Scirpua arner~canur) and cattatis {Typha domingens~s), as well as the submerged aquaitc, d~tch grass (Ruppla marrtima) Dragonfly nymphs (on the bulrush stem) are common, as are adults, such as the green darner (Anax junrus. Odonata Aeschntdael Red-wing blackbirds are charactertsttc residents of the emergent bracktsh marsh. Mclnttre collection, copyright 1986 by
Tijuana Estuary salt marsh Such experimental work wrll be possible with the creation of artrficral fresh, bracklsh, and saline marshes at the Paclfic Estuarine Research Laboratory (Chapter 6) Plgure 33. Black-crowned night herons. Juveniles klght) have streaked pfumage, Mclntire collection, copyright 1686 by 2teCJber. Most of our understanding of how bracklsh marsh vegetatron relates to satine cond~tions comes from studtes at the San Drego River marsh (20 km north of Tijuana Estuary) There, 1980 floodflows were prolonged by reservoir discharge, and rntertrdal marsh soits were oligohaline (under 10 ppt) for 2-3 months Cattails and several other brackish marsh specles invaded and dominated the intert~dal zone As has been shown experimentally by Beare (19841, the adult cattails readily tolerate salrne conditions Some individuals In experimentai treatments survtved a year In 45 ppt water, aboveground parts dted, but rhizomes were able to resprout when freshwater was resupplied Thus, the l~mitlng factors for invasion are seed germ~nation. which declines to near-zero at 20 ppt, and the period of t~me requ~red for the cattails to grow salt-tolerant rhizomes (estimated to be 2 to 3 months) Once brackrsh specres have rnvaded an rnterttdal area, 12 IS l~kely that they will persist With cont~nuaily augmented streamflows, as would occur wrth upstream wastewater discharges, specles with salt-tolerant, vegetatively reproducing adults rnlght never die out At San Drego River marsh, the cattail population that invaded in 1980 enjoyed a second expansion tn 1983, when rainfall and streamflow conlrnued late into spring With dr~er condrtions In 1984 and 1985, the populat~on declined (Zedler and Beare, in press) Table 6. Species that Boland (1 981) saw feeding in the river and temporary pools at Tijuana Estuary. Data are Frequency, i.e., the number of times the species was rsen expressed as a percentage of the total number of visits to each habitat, and total numbers of birds censused In = 10 visits to the river and 8 visits to paals). ----- Spec~es Rtver Pools -.- c Least afid western sandpipers 45a 88 Dowitcher 50 25 Wtllet 20 63 Greater yallowlegs 10 50 Black-necked st111 ef3 63 Amerrcan avocet 10 38 Sem~palmated plaver 10 25 K~ildeer 90 100 Black-beli~ed piover 20 25 Figure 34. Black-necked stilts and Amertcan avocets Total censused 226 1 019 (foreground) wade and feed in the open water of - brackish habitats. Mcintire colliection, copyright 1986 by Ledler. dAveraged for the two species
Page 1 and 2: June 1986 I THE ECOLOGY OF TIJUANA
Page 3 and 4: The findings in this report are not
Page 5 and 6: CONVERSION TABLE Metric to U.S. Cus
Page 7 and 8: Page 4.5 Energy Flow ..............
Page 9 and 10: Number Page The channel fish cornrn
Page 11 and 12: ACKNOWLEDGMENTS The California Sea
Page 13 and 14: Figure 1. Lacatlcrn of 71juana Estu
Page 15 and 16: Figure 3. Map6 of Tijuana Estuary s
Page 17 and 18: FI(I(uPc$ 4. Wei&rahOt@ patt@rns of
Page 19 and 20: also limitrng Hot, dry desert winds
Page 21 and 22: 2.3 LAND USE HlSPQWV Through exami!
Page 23 and 24: The nearby bridge remained, and ext
Page 25 and 26: flushing until mid-December 1984. E
Page 27 and 28: with seawater. Even in years with s
Page 29 and 30: flats ~n winter but not in midsumme
Page 31 and 32: Each "island" of higher topography
Page 33 and 34: The vegetation and soils of the upp
Page 35 and 36: populations (Massey 1979) The brrds
Page 37 and 38: c~n~entrations of insects, especial
Page 39 and 40: Frgufe 29. The Ifght-footed clapper
Page 41 and 42: Figure 30. During winter (above) th
Page 43: anlmal footprints, In the hardpan f
Page 47 and 48: Frgura 36 The etraracrel an& tidal
Page 49 and 50: ^_ _I __"___I _-a_. -- fable 7. Inv
Page 51 and 52: Pre- 1980 (excluding Hosrner Rehse
Page 53 and 54: Table 8. Average density (number/m2
Page 55 and 56: changes in envlronment has not been
Page 57 and 58: was dominated by goby species, Cali
Page 59 and 60: compared the ,chthyoplankton commun
Page 61 and 62: Figure 43, Birds of the intertidal
Page 63 and 64: -" and that the community was compo
Page 65 and 66: Willet (1 73) i - Water Depth (cm)
Page 67 and 68: Table 14. Early information on dune
Page 69 and 70: Figure 48. Birds that nest on the s
Page 71 and 72: CHAPTER 4 ECOSYSTEM FldNCTlONlNG St
Page 73 and 74: were no? irght-saturated untri expo
Page 75 and 76: Table 17. Conceptual model of chann
Page 77 and 78: Table 19. Net aboveground productiv
Page 79 and 80: _I___ I__-~--- 4.4.1 Nitragen Fluxe
Page 81 and 82: i i t 1 1 I Table 22. Standing crop
Page 83 and 84: calculated from chlorophyll a measu
Page 85 and 86: Dissolved Organic Biomass Carbon De
Page 87 and 88: CHAPTER 5 THE ROLE OF DISTURBANCES
Page 89 and 90: Table 25. Changes in elevation in t
Page 91 and 92: Table 26. Change in pickleweed cano
Page 93 and 94: Table 27. Occurrence (in circular 0
Page 95 and 96:
perennials can survive long periods
Page 97 and 98:
An experiment was designed to deter
Page 99 and 100:
CHAPTER 6 MANAGEMENT CONSIDERATIONS
Page 101 and 102:
Closely associated with the researc
Page 103 and 104:
c. Dredging at Tijuana Estuary will
Page 105 and 106:
Table 30. Predicted impacts of redu
Page 107 and 108:
footed clapper rails; the picklewee
Page 109 and 110:
overwashas, and slabiiizatran rs rl
Page 112 and 113:
REFERENCES Allen, L.G. 1980. Struct
Page 114 and 115:
Minsky, D. 1984. California least t
Page 116:
30272 -101 REPORT WUMENTATION 1. RE
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The Ecology of Tijuana Estuary, California: An Estuarine Profile

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