This file was created by scanning the printed publication. Errors identified by the software have been corrected; however, some errors may remain. Xeroriparian Systems Used by Desert Mule Deer in Texas And Arizona 1 Paul R. Krausman 2 , Kurt R. Rautenstrauch 3 and Bruce D. Leopold 4 Abstract.--We examined desert mule deer (Odocoileus hemionus crooki) occurrance in xeroriparian systems in Arizona and Texas. Most deer in Arizona were located in washes. Most deer in Texas were located between washes. Xeroriparian areas are important habitat components for desert mule deer when they provide forage, thermal cover and travel lanes. INTRODUCTION STUDY AREAS Desert mule deer inhabit the Sonoran and Chihuahuan Deserts of North America. Their range extends from southwest Texas to western Arizona and south into central Mexico (Wallmo 1981). Desert mule deer use of xeroriparian systems was evaluated on the northeastern edge of their range in Big Bend National Park (BBNP), southwest Texas; in the westcentral part of their range in the Belmont Mountains, central Arizona; and on the northwestern edge of their range in King Valley, southwest Arizona. Desert mule deer are a popular and important game animal, but have received limited attention by the scientific community. Clark (1953) examined desert mule deer behavior and movement patterns, Truett (1972) studied their general ecology, Krausman (1978) and Leopold (1984) evaluated their forage preferences, and Krausman (1984) and Rautenstrauch and Krausman (unpublished data) have studied desert mule deer home range size and movements. Descriptions of desert mule deer habitat are general (Phillips 1974, Anthony and Smith 1977, Dickinson and Garner 1979, Koerth 1981, Leopold and Krausman (1983) and there is little published information on desert mule deer habitat use. BBNP, Brewster Co., is representative of the rugged Chihuahuan Desert and is included in the Chisos biotic district (Dice 1943). Elevations extend from 573 m along the Rio Grande to 2384 m at Mt. Emory in the Chisos Mountains. BBNP is characterized by hot summers, mild winters and low rainfall. Temperatures exceed 38 C in the desert regions in summer and rarely freeze in winter. Precipitation occurs from May through October, ranging from 28-41 cm. Leopold and Krausman (1983) identified 10 vegetative associations in BBNP. The associations were differentiated into three categories based on dominant plant cover: creosotebush (Larrea tridentata) dominated, non-creosotebush dominated, and associations not dominated by shrubs. We began studying desert mule deer in Texas in 1972 (Krausman and Ables 1981, Leopold 1984), and in Arizona in 1979 (Krausman 1984, Rautenstrauch and Krausman, unpublished data). During these studies it became apparent that xeroriparian washes and their associated vegetation were an important component of desert mule deer habitat. Our objective in this study was to document desert mule deer use of xeroriparian systems (Johnson et ale 1981) across the northern boundary of their range and to describe the vegetation of washes used by deer. The Belmont Mountains, Maricopa Co., are 80 km west of Phoenix, cover 360 km2 , and are representative of the upper Sonoran Desert. Elevations range from 426 m to 914 m. The average annual precipitation is 20 cm. Most rain falls from January through March. Temperatures above 45 C in summer are common. 1Paper presented at the first North American Riparian Conference. [University of Arizona, Tucson. April 16-18, 1985]. 2Paul R. Krausman is Associate Professor of Wildlife, University of Arizona, Tucson, Az. 3Kurt R. Rautenstrauch is Graduate Research Assi~tant, University of Arizona, Tucson, Az. Leopold is Wildlife Research Bruce D. Assistant, University of Arizona, Tucson, Az. Krausman (1984) identified 9 vegetative associations in the Belmont Mountains. Most associations are dominated by triangleleaf bursage (Ambrosia deltoidea), brittlebush (Encelia farinosa) and creosotebush. The areas between the mountains and foothills having major washes are classified as the Triangleleaf Bursage-Transition Association. Vegetation in this association is dominated by the same three plants, but the washes 144 contain the larger trees, ironwood and paloverde (Cercidium sPP.). (~ Arizona tesota) Belmont Mountains.--The density of perennial vegetation was measured in 50-100 0.004-ha randomly located Circular plots in each of nine associations identified. In major washes that bisected associations, line intercept transects (Canfield 1941) were established to estimate the vegetational composition in xeroriparian components of the association. Over 60% of the Belmont Mountain area is in the Creosote Flats Association. Dominant plants include creosotebush and triangleleaf bursage. The species composition of the major washes is similar to the transition association. King Valley, Yuma Co., is 45 to 60 km northeast of Yuma and 110 kID southwest of the Belmont Mountains. Elevations range from 85 m at the Gila River to 450 m at the base of the surrounding mountains. The average annual precipitation at the lower end of the valley is 12 cm. King Valley.--Washes in King Valley were divided into 4 classes depending on the number of drainages and the width of the associated vegetation. Simple washes have only one drainage (a water fluve greater than 1 m wide). Complex washes (washes with more than 1 fluve) were divjded into 3 classes based on the width of the vegetation: less than 50 m wide (C1), between 50 and 150 m wide (C2) and greater than 150 m wide (C3). The slopes of the mountain ranges surrounding King Valley are sparsely vegetated and dominated creosotebush, brittlebush, white bursage by (Ambrosia dumosa), and ocotillo (Fouquieria splendens). The canyon bottoms have xeroriparian washes dominated by ironwood and paloverde. Most plant life in King Valley is restricted to the xeroriparian drainages. The areas between drainages are usually covered with wind eroded desert pavement, and have no vegetation or very sparse stands of creosotebush, brittlebush and white bursage. The dominant overstory species in the washes are little-leaf paloverde (~ microphyllum), blue paloverde (~ floridum) and ironwood. The width of the vegetation in the largest washes in King Valley is over 300 m wide. The percent cover of perennial vegetation in washes was measured using the line-intercept method (Canfield 1941). Ten transects, spaced ten m apart and running perpendicular to the flow of water, were measured in each wash. The density of perennial vegetation between 10 .0314 ha washes was measured in six to circular plots next to each wash measured. The plots were either 100 m away from the edge of the wash vegetation or half-way between the measured wash and the adjacent wash if the washes were less than 200 m apart. Contrasting Washes and Adjacent Habitat Because deer were rarely located in the mountains and foothills surrounding King Valley, this study deals only with the xeroriparian Paloverde-Ironwood Association found in the bottom of King Valley. METHODS Vegetation Sampling Shannon-Weaver Diversity indices were computed to contrast plant species diversity in washes and adjacent habitats in Texas and between areas in Arizona. Morisita coefficients of overlap (Morisita 1959) were computed to determine degree of similarity of perennial vegetation within washes and adjacent vegetatiave associations in Texas. The equivilence of percent forage species occurring in the washes and the adjacent vegetatiave associat!ons was determined using the binomial test for proportions (Zar 1984:395-400). Texas Deer Occurrence in Washes Twenty five to 50 point-quarter plots (Dix 1961) were sampled in each of ten vegetative associations identified in BBNP (Leopold and of Krausman 1983) to determine the density vegetation between washes. Texas Deer use of washes was determined from 750 independent observations of deer in three classes: initially observed in wash, within 30 m of a wash, or greater than 30 m from a wash. All observations were made from January 1980 through 1981. Habitats were sampled for deer in proportion to their availability in the study area. A transect line was established along the center of each sampled wash running parallel to the flow of water. The initial plot was randomly determined and subsequent points were 15 m apart. At each point, width of wash, and all perennial plant species to the left and right of the point were recorded. We also noted which plants were deer forage. Desirable deer forage plant species was based on diets determined by fecal analysis (Leopold 1984). Arizona Deer use of washes was determined from 1180 independent locations of 12 radio-collared deer (4 145 Table 1.--Summary and comparison of vegetative characteristics of plant associations and adjacent wash systems in Big Bend National Park, Texas. Plant association Vegetative association Total Pltnt Deer density forage 2 Creosote bush dominated 3.01 Creo-Iech-grass Creo-Iech-candel 0.74 0.65 Creo-Iech-Opuntia Creo-tarbush 2.30 Creo Flats (Loc 1)4 0.64 Creo Flats (Loc 2)5 0.04 0.24 Creo-Iech II. Non-creosotebush dominated 2.46 Vig-Iech-grass Yucca-Sotol 4.34 Sotol-Iech-grass 4.05 III. Non-shrub dominated Lech-grass (Loc 1) 1.72 Lech-grass (Loc 2) 1.04 vlash systems Deer forage 2 vlash width 3 Diversity Adjacent habitat wash Coefficient of overlap I. 43.4*6 28.3 27.8 40.1* 5.9 0.0 33.6 29.3 41.3**7 31 .1 26.4 8.2 55.8** 55.3** 18.6 23.5 19.6 5.4 13.3 25.0 NA 2.25 2.31 1.59 2.69 1.55 1.09 1.95 2.81 2.38 2.58 2.25 1.80 2.37 1.59 0.09 0.40 0.27 0.50 0.66 0.30 0.32 44.3 46.8* 53.0 62.4** 23.7 60.2 5.5 9.7 6.3 2.58 2.74 1.87 2.40 2.70 2.87 0.76 0.37 0.25 68.6* 59.1 53.1 57.7 3.8 5.2 2.73 2.35 3.01 2.69 0.35 0.60 'expressed as stems/m2 2expressed as percentage 3expressed as average of all points sampled 4Creosotebush Flats of upper elevations ~Creosotebush Flats of lower elevations *=deer forage in vegetation association significantly greater (alpha = 0.05) than in washes within association 7**=deer forage in washes significantly greater (alpha = 0.05) than adjacent association. males, 8 females) in the Belmont Mountains from 1980-1983, and 870 independent locations of 15 radio-collared deer in King Valley (4 males, 11 females)from 1982-1984. Each collared animal was located weekly with a fixed wing aircraft (Krausman et ale 1984). For each location deer were classified as being in a wash or not in a wash. In King Valley the class of wash being used was also recorded. composition of adjacent habitats. This difference was smallest in BBNP and greatest in King Valley. Texas Plant species within wash systems was not similar to the perennial species composition of adjacent habitats. Coefficients of overlap rarely exceeded 0.60 (table 1) which represents significant biological overlap (Alcoze and Zimmerman 1973). RESULTS Plant species diversity was greater in washes than in adjacent habitats for all but 4 plant associations. As equal number of associations had significantly greater forage percentages in washes than in adjacent habitats (table 1). The wash systems in low density creosotebush dominated associations were generally more diverse and had greater deer forage percentages than the adjacaent habitats. Deer using plant associations with low plant densities may therefore find higher diversity and more forage in washes than in the adjacent habitat. Characteristics of Xeroriparian Systems The average width of washes sampled in BBNP ranged from 3.8 m to 25.0 m (table 1). In general, wash systems in the lower plant density associations were wider than those with high plant density associations. Washes in the Belmont Mountains are similar in size to those in BBNP. The largest washes in King Valley are wider than washes in the two other study sites. The average width of C washes is 3 284 m, and the largest washes measured were over 350 m wide. Arizona Belmont Mountains.--Plant species within wash systems (tables 2, 3) was not similar to the perennial species composition of adjacent habitats. The plant species composition of washes was more diverse than that of the surrounding Contrasting Washes and Adjaceant Habitat in In all 3 study areas the species composition wash systems was not similar to the species 146 Table Table 2.--Vegetation in xeroriparian systems associated with the Triangleleaf bursageTransition Association, Belmont Mountains, Arizona. Plant species % cover Olneya tesota Larrea trident at a Cercidium microphyllum Cercidium floridum Prosopis juliflora Lycium andersonii Haplopappus larcifolius Acacia greggii Ambrosia ambrosioides Ambrosia deltoidea Condalia spathulata Encelia farinosa Hyptis emoryi Krameria Er:ati. Simmondsia chinensis 13.54 5.58 4.06 3.48 1.90 1.64 Total % cover 33.71 1.p T T T T T T T T 4.--Density (#/hectare) of perennial plants in the Cresoste Flats (CF) and Triangleleaf bursage-Transition (TBT) Associations, Belmont Mountains, and in the Paloverde-Ironwood (PI) Association in King Valley, Arizona. Species Belmont t-1ountains King Valley TBT CF PI Krameria spp. Larrea tridentata Carnegia gigantica Opuntia spp. Fouquiera splendens Ambrosia dumosa Ambrosia deltoides Encelia farinosa Other 12.5 280 12.5 500 12.5 2.5 1332.5 125 25 Total Diversity 2302.5 = <1% Plant species 417.5 35 25 13 .4 T 1232.5 141 .0 tesota Cercidium microphyllum Larrea tridentata Cercidium floridum Lycium andersonii Ambrosia del to idea Acacia greggii Prosopis juliflora Ambrosia ambrosioides Acacia constricta Haplopappus larcifolius Condalia spathulata Encelia farinosa Fouguieria splendens .fu:Q.lli ~ Krameria .ru:m ~ ~spp. Opuntia leptocaulis Simmondsia chinensis Sphaeralcea spp. Total % cover Diversity 1.31 1.01 1.00 Northern washes vegetation and provided a higher density of forage and cover than adjacent areas. King ~.--The average density of perennial vegetation in the habitat adjacent to washes in King Valley was 1.4 plants/100 m2 (table 4). These areas provide very little forage for deer and have no shaded bedsites. Most preferred forage species, such as ironwood, ratany, and blue paloverde are uncommon or not found outside of the washes. Because the nonwash habitat, has no overstory species and the common shrubs are small, there are no shaded bedsites in these areas. Over 8% of the ground cover in washes is overstory species that provided bedsites for deer (table 5). Southern washes % cover = <1% T 4.2 T 10.4 1less than 1 plant/ha cover) systems Table 3.--Vegetation in xeroriparian Flats associated with the Creosote Association, Belmont Mountains, Arizona. 1 T T1 70 1.91 Diversity (H') 1 T 32.5 712.5 2.5 7.5 2.60 1.97 8.17 7.63 4.82 1.84 T 9.65 8.34 5.46 4.92 3.84 2.41 1.51 1.36 1.29 1.30 T 4 2·i T Deer Occurance in Washes Texas o T o o T o T T o o T T Arizona T Belmont Mountains.--Deer use of xeroriparian systems was highest in summer (83.3%) followed by fall (82.2%) and spring (70.5%) (table 6). During the winter deer use of washes was 42.1%. Overall, 842 of 1180 (71.4%) deer were located in washes (table 6). o o o o 31.27 2.01 Of 750 deer observations only 40 (5.3%) occurred within a wash, and 29 (3.9%) within 30 m of a wash. T T T 39.11 2.24 King ~.--Over 99% of the deer locations in King Valley were in washes (table 7). The six locations that were not in washes were either in cover) 147 Table 5.--Percent cover of vegetation in 4 classes in King Valley, Arizona. ~ Av. Av. Av. Av. Av. n ..Q2. wash Table 7.--The number (and percent) of deer locations in 4 wash classes in King Valley, Arizona • n Simple width of wash 15.74 39.51 89.62 284.3 % cover of vegetation 30.40 29.36 23.76 24.77 II drainages 1.0 3.2 6.93 12.95 It of species 9.05 9.32 10.75 7.5 8.05 % of overstory cover 10.55 8.84 8.46 Hilaria rigid a Atriplex polycarpa 0.05 1.02 0.08 0.28 0.94 0.11 0.19 0.35 0.41 0.30 0.10 0.03 0.96 0.25 0.13 3.54 1.88 1.42 1.42 2.55 3.28 5.10 3.96 3.32 10.48 11 .89 11 .05 0.18 0.31 0.23 3.60 2.85 2.56 3.12 1.18 0.65 2.57 2.94 1.67 0.86 1.28 1.09 Acacia~ Prosopis julif:lora Krameria ~ Cercidium microphyllum .Q... floridum Olneya tesota Larrea tr1dentata Sphaeralcea SPp. ~ andersQnii Ambrosia dumosa Encelia farinQsa Other species Diversity (H') 2.10 2.12 1.93 0.56 0.79 0.52 0.25 0.24 5.64 0.81 9.97 2.52 3.47 0.16 0.55 1.38 n C2 Other £i Females 47 (9.8) 184 62 172 (39.1)(36.6)(13.2) 5 ( 1.1) Males 32 (18.6) 44 28 67 (25.6)(39.0)(16.3) 1 (0.1) In Arizona, most deer were located in washes. III both Arizona study areas the plant species diversity was twice as high in the xeroriparian washes. Food and cover was scarce outside of these washes in King Valley and less abundant than in washes in the Belmont Mountains. Desert mule deer in Arizona may be selecting xeroriparian washes because they provide more food, cover, and travel lanes than the surrounding areas. Xeroriparian systems are an important part of desert mule deer habitat in xeric ranges. 2.03 LITERATURE CITED agriculture fields or disturbed areas agriculture at the south end of King Valley. near DISCUSSION Deer in BBNP are not as dependent upon xeroriparian systems as deer in Arizona. In Texas, deer forage is abundant in the habitats adjacent to wash systems. Although the plant species composition of washes and adjacent habitats are not similar, both areas have relatively equal diversity, except in plant associations with low plant densities. Deer use of these areas was minimal «1.0 deer/km2) compared to plant associations with higher plant densities (>1.5/deer km 2 ) (Leopold 1984). The greater plant densities and diversities in the interwash regions in BBNP allows deer to find forage and cover in these areas instead of in washes, as deer in Arizona must. Alcoze, T. M., and E. G. Zimmerman. 1973. Food habits and dietary overlap of two heteromyid rodents from the mesquite plains of Texas. J. Mammal. 54:900-908. Anthony, R. G. , and N. S. Smith. 1977. Ecological relationships between mule deer and white-tailed deer in southeastern Arizona. Ecol. Monogr. 47:255-277. Canfield, R. H. 1941. Application of the line interception method in sampling range vegetation. J. For. 39:388-394. Clark, E. D. 1953. A study of the behavior and movements of the Tucson Mountain mule deer. M.S. Thesis, Univ. Arizona, Tucson. 111 p. Dice, L. R. 1943. The biotic provinces of North America. Univ. Michigan Press, Ann Arbor. 78 p. Dickinson, T. G., and G. W. Garner. 1979. Home range use and movements of desert mule deer in southwestern Texas. Proc. Ann. Conf. S.E. Assoc. Fish and Wildl. Agencies 33:267-278. Table 6.--Desert mule deer (4 males, 8 females) occurrence in washes in the Belmont Mountains, Arizona from 1981-1982. SEASONS Jan-Mar Habitat Occurrences Percent occurrences in washes Apr-Jun Jul-Sep Oct-Dec Total Wash Other Wash Other Wash Other Wash Other Wash Other 82 113 322 135 304 61 134 29 842 338 42.1% 70.5% 83.3% 148 82.2% 71.4% bighorn sheep. Final Rept. 9-07-30-X069 to USDI/B.R. Phoenix, Arizona. Leopold, B. D. 1984. Ecology of desert mule deer in Big Bend National Park, Texas. Ph.D. Dissertation, Univ. Arizona, Tucson. 172 p. _________ , and P. R. Krausman. 1983. Plant communities of the lower desert shrubland in Big Bend National Park, Texas. Second Chihuahuan Desert Symposium, Alpine, Texas. In Press. Morista, M. 1959. Measuring of interspecific association and similarity between communities. Mem. Fac. Sci. Kyrishu Univ., Sere E. BioI. 3:65-80. The annual behavioral Phillips, J. L. 1974. cycle of desert mule deer (Odocoileus hemionus crooki) in relation to vegetative use. M.S. Thesis, SuI Ross State Univ., Alpine, Texas. 60 p. Truett, J. C. 1972. Ecology of the desert mule deer, Odocoileus hemionus crooki Mearns in southeastern Arizona. Ph.D. Dissertation, Univ. Arizona, Tucson. 64 p. Wallmo, O. C. 1981. Mule and black-tailed deer distribution and habitats. pp. 1-25 jn O. C. Wallmo, ed. Mule and black-tailed deer of North America. Univ. Nebraska Press, Lincoln. 605 p. Zar, J. H. 1974. Biostatistical analysis. Prentice-Hall Inc., Englewood Cliffs, N.J. 620 p. Dix, R. L. 1969. An application of the pointcentered quarter method of the sampling of grassland vegetation. J. Range Manage. 14:63-69. Johnson, R. R., S. W. Carothers, and J. M. Simpson. 1981. A riparian classification system. p 375-382 in R. E. Warner, and K. M. Hendrix, eds. California riparian systems: ecology, conservation, and productive management. Univ. of California Press, Berkeley. 1035 p. Koerth, B. H., Jr. 1981. Habitat use, herd ecology, and seasonal movements of mule deer in the Texas Panhandle. M.S. Thesis, Texas Tech Univ., Lubbock. 103 p. Krausman, P. R., and E. D. Ables. 1981. Ecology of the Carmen Mountains white-tailed deer. National Park Service Sci. Monogr. 15:1-114. __________ , J. J. Hervert, and L. L. Ordway. 1984. Radio tracking desert mule deer and bighorn sheep with light aircraft. pp. 115118 in P. R. Krausman and N. S. Smith, eds. Deer in the southwest: a workshop. School of Renewable Natural Resources, Univ. of Arizona, Tucson, Arizona. 1978. Forage relationships between two deer species in Big Bend National Park, Texas. J. Wildl. Manage. 42:101-107. __________ , 1984. Impacts of the Central Arizona Project on desert mule deer and desert 149