Aquatic and Semiaquatic Vegetation of Utah Lake and Its Bays Jack D

Great Basin Naturalist Memoirs Volume 5 Utah Lake Monograph Article 5 2-1-1981 Aquatic and semiaquatic vegetation of Utah Lake and its bays Jack D. Brotherson Department of Botany and Range Science, Brigham Young University, Provo, Utah 84602 Follow this and additional works at: https://scholarsarchive.byu.edu/gbnm Recommended Citation Brotherson, Jack D. (1981) "Aquatic and semiaquatic vegetation of Utah Lake and its bays," Great Basin Naturalist Memoirs: Vol. 5 , Article 5. Available at: https://scholarsarchive.byu.edu/gbnm/vol5/iss1/5 This Article is brought to you for free and open access by the Western North American Naturalist Publications at BYU ScholarsArchive. It has been accepted for inclusion in Great Basin Naturalist Memoirs by an authorized editor of BYU ScholarsArchive. For more information, please contact [email protected], [email protected]. AQUATIC AND SEMIAQUATIC VEGETATION OF UTAH LAKE AND ITS BAYS Jack D. BrothersoiV .\bstract.— Seven aquatic and seniiaquatic comniiinities surrounding Utah Lake and its bays are described. Sim- ilarities and differences in the community types are discussed. Prevalent species in each type are given. The flora contained 48.3 species, 150 of which were prevalent enough to be included in the quantitative data analysis. Dis- tichlis stricta was the most important and widespread species. Total cover varied in the communities from 10 to 77 percent. Asexual reproduction was shown to increase in importance as moisture in the soil increased. Introduced exotic species were shown to invade most successfully those habitats that show the greatest variability in moisture and/or those that have the greatest internal variation. Initial comments on the vegetation sin- and Murphy (1951), in conjunction with stud- rounding Utah Lake were recorded as early ies of passerine birds found in the vicinity of as 23 September 1776. Fathers Atanasio Do- the lake, studied and classified the plant com- minguez and Silvestre Velez de Escalante mimities frequented by the birds on Bird Is- and their party camped on that date adjacent land and the area from the mouth of Provo to the southeast shore of the Lake, and it was River to the south end of the Provo Munici- during their stay that they penned the first pal Airport. Barnett (1964) studied waterfowl known records concerning plant communities habitat at Powell's Slough on the east shores in the area. They recorded wide meadows, of the lake. He placed the vegetation found abmidant pasture, and marsh communities on there into four major communities based the shores of Utah Lake and noted the preva- upon habitat type and plant species present. lence of poplars, willows, flax, and hemp Christensen (1965) studied two Tamarix along the streams and east side of the lake ramosissimo-Salix amygdaloides stands near (Chevez and Warner 1976). Other early visits the mouth of the Spanish Fork River and pre- were made to the area by trappers, mountain dicted that ramosissima (which he imder- men, and explorers. However, their written stood to be T. pentrandra) as a type would records yield little information on the vegeta- eventually replace Solix amygdaloides as tion of Utah Lake that is not extractable from these trees die. Foster (1968) in a statewide the Dominguez-Velez de Escalante journals. study of the major plant communities of Utah We leam from their writings of occasional recognized four community types around bogs, communities containing reeds and Utah Lake. His plant community types are abimdant marsh grasses, infrequent patches broad in definition and based on observation of wild sage, and swamps filled with Lemna rather than analytical data. Coombs (1970) and Chum (Wakefield 1933). examined the vascular aquatic and semi- More detailed studies of the plant commu- aquatic vegetation around the lake and de- nities found in and around Utah Lake have limited 29 plant communities in 7 major been made only in the past 50 years. Cottom types. Local taxonomic and ecological studies (1926) made the first quantitative studies of (e.g.. Weight 1928, Leichtv 1952, Lawler the vegetation of the lake. He listed 11 for- 1960, Bessey 1960, Arnold 1960, White 1963, mations and 20 associations that he described Skougard 1976) have been of great value by as making up the vegetation aroimd Utah identifying many of the plant species grow- Lake and adjacent Utah Valley. Wakefield ing in and aroimd the lake. (1937) reported on vegetational changes over Even though Utah Lake and its environs is a six-year period on the lakeshore south of in many localities well studied from the natu- the present Provo boat harbor. Beck (1942) ral history and ecological points of view. 'Department of Botany and Range Science. Brigham Young University, Provo. Utah 84602. 68 1981 Utah Lake M ONOGRAPH little has been reported in the literature with Ultimately, each stand and/or community regard to (1) man's impact on the plant com- was compared to all other stands and/or mimities since settlement, (2) the influence commimities. This process resulted in the and changes wrought by introduced exotic production of interstand or intercommunity plants, (3) species composition for the major similarity index values (Ruzicka 1958). A commimity types, (4) environmental factors matrix of similarity index values was con- influencing the distribution of major commu- structed. The similarity values were clustered nity types, (5) community diversity, and (6) by the pair-group clustering procedures de- information with regard to successional scribed by Sneath and Sokal (1973). changes and life form patterns along environ- Moisture index data were assigned to each mental gradients. stand using a modification of the methods employed by Coombs (1970). Moisture class- Methods es were set up as reported in Table 2. Floristics and nomenclature follow Forty stands of data were selected from Cronquist et al. (1977) for the mon- the hterature (Coombs 1970, Bamett 1964, ocotyledons and Holmgren and Reveal (1966) Christensen 1965) and combined with 10 for the dicotyledons. stands studied by the author in the summer of 1974. Percent sum-frequency values for each Results species (Phillips 1959), total cover information (Brown 1968), and moisture index values General Vegetation Descriptions (Coombs 1970) were then assigned to all 50 The aquatic and semiaquatic communities stands. Percent sum-frequency figures were surrounding Utah Lake form a band of vege- used to give the species data from the differ- tation along the lake shore varying in width ent sources equivalent standing. Where in- from 20 m or less on the western shore to 400 formation was questionable and /or lacking m on the eastern shore. In addition, two large (especially with respect to moisture informa- bays, Provo Bay and Goshen Bay, extend tion), supplementary field observations were away from the lake in eastern and southern made in the summer of 1976. Of the stand directions, respectively, and contain a major- data taken from the literature only those hav- ity of the land area occupied by the aquatic ing relatively complete information were and semiaquatic communities. used in this analysis. During this investigaton 483 plant species Species lists (150 total) were assembled for were found to be part of the Utah Lake vege- each stand. Importance values (Warner and tation. Of these, only 150 were of sufficient Harper 1972) were then computed for each importance to include in the quantitative species in relationship to the total vegetative data analyses. Only 13 species were included complex and the major communities found in in a prevalence list for the entire area and, as the area. From this information, prevalent can be seen from Table 1, the list is highly species tables were compiled (Tables 4-9). The number of prevalent species included on Table 1. The prevalent species found in the vegeta- any one list was equal to the mean number of tion of Utah Lake with their importance vahie. species reported for the stands of a given Scientific name commimity. The prevalents are listed in de- creasing order of importance and are the most frequent species in the community; un- common or rare species are ignored. Diversity indices (McArthur 1972) were computed from the percent sum-frequency data using the formula: where Di is the diversity index and pi is the relative proportion each species contributes to the overall composition of a community. 70 Great Basin Naturalist Memoirs No. 5 dominated by grasses and sedges, with Dis- exclusively by a single species or clone even tichlis stricta being the most important and though the abiotic environment is homoge- widespread species. nous. Seven major vegetative types exist around Average values for selected environmental the Lake (Tables 2 and 3), each occupying variables are given for the seven major vege- unique habitats and each showing varying de- tative types in Table 2. It will be seen that grees of internal structure with respect to the number of stands considered for each subcommunity dominants. This subcommunity is not equal, varying from 5 to community variation is related in some de- 16. The communities vary with respect to gree to the prominance of asexual reproduc- moisture from continuous inundation to sea- tion (by rhizomes) in the dominant species. sonal inundation, and finally to those that When dominant species reproduce vegeta- never experience standing water or high wa- titively, large areas may be occupied almost ter tables. Communities on the dry end of the Table 2. Selected environmental characteristics of major plant communities surrounding Utah Lake. 1981 Utah Lake MONOGRAPH 71 Table 4. The prevalent species found in the hnlrnsh- cattail marsh communities of Utah Lake with their importance values. Scientific name Importance values Typha latifolia Lemna minor 6243 Scirpus actitus 5471 Berula crcrta 3457 Eleocluiris palusths 1771 Spirodchi polyrhiza 1257 Riccia fluitans 957 Polypogon monspeliensis 657 Epilobium adenocaulon 614 Lycopus Ittcidus 314 Nasturtium officinale 3(K) Scirpus americanus 286 Table 5.

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