The American Southwest and Middle America
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Rr.PRINTELD FOR PRWATE D1STRTBUTTON LIMNCLOGY PROW IN NORTH AMERICA EDI 1 ED b DA FREY MADISON - THE UNIVERSITY OF WISCONSIN PR IN I'D PRESS, 1963 N THE UNITED STATES OF AMERICA COPYRIGh T BY REGENTS OF U.W., 1963 14 Gerald A. Cole The American Southwest and Middle America The American Southwest (Fig. 14.1) and Middle cally. Many published data exist for other re- America, covered in this chapter, is probably the gions. For this reason, it seems advisable to most heterogeneous geographic region considered treat some lakes on an artificial, political basis, in this book. The area covers about 25° of lati- and others on the basis of districts of similar tude and 42° longitude and amounts to more origin or location within the same physiographic than 3.8 million km'. Altitudes range from sea province. Lack of published studies or explora- level to 5,500 m above sea level, and extremes in tion of any kind in many areas leaves no alter- climate, edaphic factors, and biotic zones are the native except to point out, in such cases, the rule. existence of water bodies and the opportunities Lakes of this vast area owe their origins to for future original research there. many processes. There is no such thing as one One of the most important single papers on lake district to be considered here. The phrase the limnology of the Southwest and Middle lake district is used loosely; pond district is the America is that of Deevey (1957), who reported proper terminology in many instances. Further- on waters from Texas to El Salvador. His publi- more, the region contains unique aquatic habi- cation, though based on hurried visits to the area tats: thermal springs, extremely saline waters, and a few data from pre-existing literature, is the lava-collapse ponds, the cenotes of Yucatan, most valuable summary and synthesis of south- water-containing caves, and ephemeral ponds, to western and Middle American limnology. To be mention a few. rewarding, future work in this area should be on Yet the southwestern states and republics of a systematic regional and natural basis, con- Middle America are not separate natural entities. cerned with individual lake districts. They are related climatically and geologically. Superficially it appears that the arid Southwest The Colorado Plateau is shared in part by New has remained practically unchanged since settle- Mexico and northern Arizona, and the Texas ment by European man. This is true to a relative coastal plain continues far southward into Mexico. extent, but disturbances are far greater than ex- The Basin and Range physiographic province is pected. Miller (1961) discussed the modifications common to Trans-Pecos Texas, southern New of aboriginal aquatic habitats in the Southwest Mexico and Arizona, and the northern portion of with particular emphasis on the effects on fish Mexico to about latitude 18° N. Similarly, Mid- faunas. Since 1900, six or seven species have be- dle American republics share Caribbean and Pa- come extinct, and at least 13 additional forms cific coastal lowlands, mountain chains, and other are seriously threatened. Many streams which geologic features. were permanent during the latter part of the 19th Some areas are practically unknown limnologi- century now flow intermittently, carrying heavy 393 115 113 111 109 107 105 103 101 99 97 95 93 91 4 . 137 k UTAH ROCKY 0 \ "Ikkj•ZS7_7_, ---- Q 39 \ MTN. Co L C\R A D 0 \ S._ — \*\ PROVINCE ' ■ Ic_k'S \ ■ _ \ ‘r. 35 NEV. --, i cr — — \FfET,CAS /.... Nc\\ 37 KAI BAB co C.+ ■ 0 PLATEAU \ SANT FE 7 PLATE A U River 33 I \ 29 q \ LBUQUERQUE , \ 26 30 FLAGSTAFF0F GRANTSLAVA "%. N QO 31 DALLAS RI, A ii BED 20 \ ' i 35 0 1 8 2 1 4% 4 6 \ 8 ION 4 19 1 46) '74 5 \ ROSWELL 1 7 '' LLANO 46 S. t I ° \ 2 3 -1 S ' c" soN •Peit, I S ' 09 I 22 ESTACADO / 12 . 13 ? ` ON Gila 25 3 2 7 33 ■ NAT 28 / ct, 't, N 44 ARIZ. River J 45 TUCSON IS 24 • • S \ • 37 1 -- EDWARDS 43 29 . c • At 39 . 14 J Organ Pipe • • • b 38 PLATEAU N.M. R A N G E 31 GULF 27 OF 29 -P 200 MEXICO 25 111 115 113 109 107 105 103 101 97 95' 396 GERALD A. COLE few published data in the realm of limnology, al- Basin and Range province occupies the south- though ichthyologists have collected for a period western third of the state. Because elevations of many years from Texas waters. Preliminary range from 1,000 to 4,600 m above sea level, investigations by Wiebe (1934) on some im- biotic regions include such extremes as the Chi- poundments represented the beginning of Texas huahuan desert in the south and the cool, coni- limnology. One of the first comprehensive stud- ferous forest at higher altitudes in the north. ies was that of Harris and Silvey (1940), con- More than half the state receives less than 37.5 cerned with four reservoirs in the northeastern cm precipitation per annum, and, in the United part of the state. This was followed by the paper States, only Connecticut has a smaller total area of Cheatum et al. (1942) on another impound- covered by lakes, ponds, and streams. The most ment farther east. Students of these men have arid region is the southwestern half, although a investigated many aspects of Texas fisheries and tongue of aridity extends up the Rio Grande reservoir limnology since the 1930's. Titles of Valley almost to the Colorado state line. graduate theses on fishery biology and related In the Sangre de Cristo Mountains in north- subjects in Texas compiled by the Sport Fishing central New Mexico are some small natural lakes Institute (1959) are abundant, particularly un- which may be the only glacial lakes in the entire published Masters' theses from North Texas area treated in this chapter. Most of these are State University. Patterson (1942) includes titles at elevations between 2,100 m and 3,350 m and of two other theses in the bibliography of her seem to be intermediate between cirque and mo- paper on the plankton of White Rock Lake, raine lakes (Koster, personal communication). Texas. The formative montane glaciers were small in Furthermore, the Texas Game and Fish Com- these mountains. This small lake district is in mission, under the direction of Marion Toole, the headwaters of the South Canadian, Rio has prepared a series of reports concerning basic Grande, and Pecos rivers. investigations of many Texas lakes and streams. The largest body of water in New Mexico Monthly field chemical analyses have been made is Elephant Butte Reservoir, a long, narrow im- on most of the big impoundments in the state. poundment on the Rio Grande. In general, the Deevey (1957) briefly reconnoitred some ponds most important lakes of the state are man-made. of the Texas coastal plain and the arid Trans- Many New Mexican waters are characterized Pecos region. Most other studies of Texas lakes, by a high sulfate content, a reflection of the especially those on the Llano Estacado, have widespread and commercially-important gypsum. been carried out by geologists and paleoecologists Some exceptions are seen in the soft waters of and will be mentioned in a later section. the small lake district on the crest of the Chuska There is still much to be learned about the Mountains (Megard, 1961) and in the mineralized lacustrine fauna and flora of Texas, although the spring water of Ojo Caliente near Taos. The lack is not as great as in New Mexico and Ari- latter was cited as an example of carbonate zona. Examples are the paper of Tressler (1954) water in the classification devised by Clarke on ostracods in Texas and reports by several (1924), and the dominant cation is sodium. Also, workers, including Comita (1951), on copepods. the small trout lakes cursorily surveyed by Gers- Comparable papers do not exist for the other bacher (1935) in the mountains of north-central southwestern states. Of particular interest are New Mexico seem to be soft-water lakes. the many papers of Silvey and Roach on the One important biological effect, ultimately as- aquatic actinomycetes of Texas (e.g., Roach and cribed to high sulfates, was described by Clark Silvey, 1958; Silvey and Roach, 1959). and Greenbank (1936) who investigated the re- curring catastrophic fish-kills in Park Lake at New Mexico an elevation of about 1,430 m near Santa Rosa. Four physiographic provinces are represented in The reduction of SO4 to H2S following the death New Mexico: the Rocky Mountains extend in- and decay of an abundant algal growth was to the north-central portion; the Great Plains, succeeded by sudden strong winds which mixed including a part of the Llano Estacado, lie along the waters. Results were disastrous. Those au- the eastern margin; the Colorado Plateau ex- thors compared Park Lake with the nearby Club tends across the northwest; and a portion of the Lake in which fish-kills had not occurred. Both ▪ The American Southwest and Middle America 395 . ,.:. silt loads in flash floods through deeply en- . .. :,..,. al bp 1 ,--. < , • g g trenched arroyos. Many smaller streams and d cw ..a 1-4 . 6 E1%, 7.-: . 0 '4 '4 „s -0 • as • to springs are gone, and the freshwater marshy 0 g›0, a) .) 0 . 0 z . „-, ,„ 0 c , 0 _ c., 0 , . ,... -. - 4 areas known as cienegas have virtually disap- ■: . ..'.. 71(. cd' ,c,d, -8 -- , •j..1 ,' 1A >- ■ ;'' th' >, tz1 . .-5 P4 ,,, P.4 •f .., peared. Over-grazing, lumbering, pollution, river =, 3 cu -0) 0 ci) — — m1 d 42 ' ' impoundment, dredging, ditching, pumping ground .5: 0 uo cn' , ,a =8 , P:1 4 2 4e) , E .ts,P, g water, and the introduction of exotic species „-; 06 6 c6 have been extremely important factors in habi- .1- .1- 1 71- tat modification and the resultant alteration of faunas.