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Xeroriparian Systems Used by Desert Mule Deer in Texas And Arizona1

Paul R. Krausman2 , Kurt R. Rautenstrauch3 and Bruce D. Leopold4

Abstract.--We examined desert mule deer (Odocoileus hemionus crooki) occurrance in xeroriparian systems in 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 Desert mule deer use of xeroriparian systems Chihuahuan Deserts of North America. Their range was evaluated on the northeastern edge of their extends from southwest Texas to western Arizona range in Big Bend National Park (BBNP), southwest and south into central Mexico (Wallmo 1981). Texas; in the westcentral part of their range in the Belmont Mountains, central Arizona; and on the Desert mule deer are a popular and important northwestern edge of their range in King Valley, game animal, but have received limited attention southwest Arizona. by the scientific community. Clark (1953) examined desert mule deer behavior and movement BBNP, Brewster Co., is representative of the patterns, Truett (1972) studied their general rugged Chihuahuan Desert and is included in the ecology, Krausman (1978) and Leopold (1984) Chisos biotic district (Dice 1943). Elevations evaluated their forage preferences, and Krausman extend from 573 m along the Rio Grande to 2384 m (1984) and Rautenstrauch and Krausman (unpublished at Mt. Emory in the Chisos Mountains. data) have studied desert mule deer home range size and movements. Descriptions of desert mule BBNP is characterized by hot summers, mild deer habitat are general (Phillips 1974, Anthony winters and low rainfall. Temperatures exceed 38 and Smith 1977, Dickinson and Garner 1979, Koerth C in the desert regions in summer and rarely 1981, Leopold and Krausman (1983) and there is freeze in winter. Precipitation occurs from May little published information on desert mule deer through October, ranging from 28-41 cm. habitat use. Leopold and Krausman (1983) identified 10 We began studying desert mule deer in Texas vegetative associations in BBNP. The associations in 1972 (Krausman and Ables 1981, Leopold 1984), were differentiated into three categories based on and in Arizona in 1979 (Krausman 1984, dominant plant cover: creosotebush (Larrea Rautenstrauch and Krausman, unpublished data). tridentata) dominated, non-creosotebush dominated, During these studies it became apparent that and associations not dominated by shrubs. xeroriparian washes and their associated vegetation were an important component of desert The Belmont Mountains, Maricopa Co., are 80 mule deer habitat. Our objective in this study km west of Phoenix, cover 360 km2 , and are was to document desert mule deer use of representative of the upper . xeroriparian systems (Johnson et ale 1981) across Elevations range from 426 m to 914 m. the northern boundary of their range and to describe the vegetation of washes used by deer. 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 Krausman (1984) identified 9 vegetative Riparian Conference. [University of Arizona, associations in the Belmont Mountains. Most Tucson. April 16-18, 1985]. associations are dominated by triangleleaf bursage 2Paul R. Krausman is Associate Professor of (Ambrosia deltoidea), brittlebush (Encelia Wildlife, University of Arizona, Tucson, Az. farinosa) and creosotebush. The areas between the 3Kurt R. Rautenstrauch is Graduate Research mountains and foothills having major washes are Assi~tant, University of Arizona, Tucson, Az. classified as the Triangleleaf Bursage-Transition Bruce D. Leopold is Wildlife Research Association. Vegetation in this association is Assistant, University of Arizona, Tucson, Az. dominated by the same three plants, but the washes

144 contain the larger trees, ironwood (~ tesota) Arizona and paloverde (Cercidium sPP.). Belmont Mountains.--The density of perennial vegetation was measured in 50-100 0.004-ha Over 60% of the Belmont Mountain area is in randomly located Circular plots in each of nine the Creosote Flats Association. Dominant plants associations identified. In major washes that include creosotebush and triangleleaf bursage. bisected associations, line intercept transects The species composition of the major washes is (Canfield 1941) were established to estimate similar to the transition association. the vegetational composition in xeroriparian components of the association. King Valley, Yuma Co., is 45 to 60 km northeast of Yuma and 110 kID southwest of the King Valley.--Washes in King Valley were Belmont Mountains. Elevations range from 85 m at divided into 4 classes depending on the number of the to 450 m at the base of the drainages and the width of the associated surrounding mountains. The average annual vegetation. Simple washes have only one drainage precipitation at the lower end of the valley is 12 (a water fluve greater than 1 m wide). Complex cm. washes (washes with more than 1 fluve) were divjded into 3 classes based on the width of the The slopes of the mountain ranges surrounding vegetation: less than 50 m wide (C1), between 50 King Valley are sparsely vegetated and dominated and 150 m wide (C2) and greater than 150 m wide by creosotebush, brittlebush, white bursage (C3). (Ambrosia dumosa), and ocotillo (Fouquieria splendens). The canyon bottoms have xeroriparian The percent cover of perennial vegetation in washes dominated by ironwood and paloverde. washes was measured using the line-intercept method (Canfield 1941). Ten transects, spaced ten Most plant life in King Valley is restricted m apart and running perpendicular to the flow of to the xeroriparian drainages. The areas between water, were measured in each wash. drainages are usually covered with wind eroded desert pavement, and have no vegetation or very The density of perennial vegetation between sparse stands of creosotebush, brittlebush and washes was measured in six to 10 .0314 ha white bursage. circular plots next to each wash measured. The plots were either 100 m away from the edge of the The dominant overstory species in the washes wash vegetation or half-way between the measured are little-leaf paloverde (~ microphyllum), blue wash and the adjacent wash if the washes were less paloverde (~ floridum) and ironwood. The width than 200 m apart. of the vegetation in the largest washes in King Valley is over 300 m wide. Contrasting Washes and Adjacent Habitat

Because deer were rarely located in the Shannon-Weaver Diversity indices were mountains and foothills surrounding King Valley, computed to contrast plant species diversity in this study deals only with the xeroriparian washes and adjacent habitats in Texas and between Paloverde-Ironwood Association found in the bottom areas in Arizona. Morisita coefficients of of King Valley. 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 METHODS forage species occurring in the washes and the adjacent vegetatiave associat!ons was determined Vegetation Sampling 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 Texas associations identified in BBNP (Leopold and Krausman 1983) to determine the density of Deer use of washes was determined from 750 vegetation between washes. independent observations of deer in three classes: initially observed in wash, within 30 m of a wash, A transect line was established along the or greater than 30 m from a wash. All center of each sampled wash running parallel to observations were made from January 1980 through the flow of water. The initial plot was randomly 1981. Habitats were sampled for deer in determined and subsequent points were 15 m apart. proportion to their availability in the study At each point, width of wash, and all perennial area. plant species to the left and right of the point were recorded. We also noted which plants were Arizona deer forage. Desirable deer forage plant species was based on diets determined by fecal analysis Deer use of washes was determined from 1180 (Leopold 1984). 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 vlash systems Diversity

Vegetative Total Pltnt Deer Deer vlash Adjacent Coefficient association density forage2 forage2 width3 habitat wash of overlap

I. Creosote bush dominated Creo-Iech-grass 3.01 43.4*6 29.3 18.6 2.25 2.81 0.09 Creo-Iech-candel 0.74 28.3 41.3**7 23.5 2.31 2.38 0.40 Creo-Iech-Opuntia 0.65 27.8 31 .1 19.6 1.59 2.58 0.27 Creo-tarbush 2.30 40.1* 26.4 5.4 2.69 2.25 0.50 Creo Flats (Loc 1)4 0.64 5.9 8.2 13.3 1.55 1.80 0.66 Creo Flats (Loc 2)5 0.04 0.0 55.8** 25.0 1.09 2.37 0.30 Creo-Iech 0.24 33.6 55.3** NA 1.95 1.59 0.32 II. Non-creosotebush dominated Vig-Iech-grass 2.46 44.3 62.4** 5.5 2.58 2.40 0.76 Yucca-Sotol 4.34 46.8* 23.7 9.7 2.74 2.70 0.37 Sotol-Iech-grass 4.05 53.0 60.2 6.3 1.87 2.87 0.25 III. Non-shrub dominated Lech-grass (Loc 1) 1.72 68.6* 53.1 3.8 2.73 3.01 0.35 Lech-grass (Loc 2) 1.04 59.1 57.7 5.2 2.35 2.69 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 composition of adjacent habitats. This difference 1980-1983, and 870 independent locations of 15 was smallest in BBNP and greatest in King Valley. radio-collared deer in King Valley (4 males, 11 females)from 1982-1984. Each collared animal was located weekly with a fixed wing aircraft Texas (Krausman et ale 1984). For each location deer were classified as being in a wash or not in a Plant species within wash systems was not wash. In King Valley the class of wash being used similar to the perennial species composition of was also recorded. adjacent habitats. Coefficients of overlap rarely exceeded 0.60 (table 1) which represents significant biological overlap (Alcoze and RESULTS Zimmerman 1973).

Characteristics of Xeroriparian Systems Plant species diversity was greater in washes than in adjacent habitats for all but 4 plant The average width of washes sampled in BBNP associations. As equal number of associations had ranged from 3.8 m to 25.0 m (table 1). In significantly greater forage percentages in washes general, wash systems in the lower plant density than in adjacent habitats (table 1). The wash associations were wider than those with high plant systems in low density creosotebush dominated density associations. associations were generally more diverse and had greater deer forage percentages than the adjacaent Washes in the Belmont Mountains are similar habitats. Deer using plant associations with low in size to those in BBNP. The largest washes in plant densities may therefore find higher King Valley are wider than washes in the two other diversity and more forage in washes than in the study sites. The average width of C washes is adjacent habitat. 3 284 m, and the largest washes measured were over 350 m wide. Arizona

Belmont Mountains.--Plant species within wash Contrasting Washes and Adjaceant Habitat systems (tables 2, 3) was not similar to the perennial species composition of adjacent In all 3 study areas the species composition habitats. The plant species composition of washes in wash systems was not similar to the species was more diverse than that of the surrounding

146 Table 2.--Vegetation in xeroriparian systems Table 4.--Density (#/hectare) of perennial plants associated with the Triangleleaf bursage­ in the Cresoste Flats (CF) and Transition Association, Belmont Mountains, Triangleleaf bursage-Transition (TBT) Arizona. Associations, Belmont Mountains, and in the Paloverde-Ironwood (PI) Association in King Plant species % cover Valley, Arizona.

Olneya tesota 13.54 Larrea trident at a 5.58 Cercidium microphyllum 4.06 Belmont t-1ountains King Valley Cercidium floridum 3.48 Species TBT CF PI Prosopis juliflora 1.90 Lycium andersonii 1.64 Haplopappus larcifolius 1.p Krameria spp. 12.5 32.5 T1 Acacia greggii T Larrea tridentata 280 712.5 70 Ambrosia ambrosioides T Carnegia gigantica 12.5 2.5 T Ambrosia deltoidea T Opuntia spp. 500 7.5 4.2 Condalia spathulata T Fouquiera splendens 12.5 T Encelia farinosa T Ambrosia dumosa 2.5 10.4 Hyptis emoryi T Ambrosia deltoides 1332.5 417.5 Krameria Er:ati. T Encelia farinosa 125 35 13 .4 Simmondsia chinensis T Other 25 25 T

Total % cover 33.71 Total 2302.5 1232.5 141 .0 Diversity 1.91 Diversity (H') 1.31 1.01 1.00

1 T = <1% cover) 1less than 1 plant/ha

Table 3.--Vegetation in xeroriparian systems vegetation and provided a higher density of forage associated with the Creosote Flats and cover than adjacent areas. Association, Belmont Mountains, Arizona. King ~.--The average density of Northern Southern perennial vegetation in the habitat adjacent to Plant species washes washes washes in King Valley was 1.4 plants/100 m2 (table % cover 4). These areas provide very little forage for deer and have no shaded bedsites. Most preferred forage species, such as ironwood, ratany, and blue ~ tesota 2.60 9.65 paloverde are uncommon or not found outside of the Cercidium microphyllum 1.97 8.34 washes. Because the nonwash habitat, has no Larrea tridentata 8.17 5.46 overstory species and the common shrubs are small, Cercidium floridum 7.63 4.92 there are no shaded bedsites in these areas. Over Lycium andersonii 4.82 3.84 8% of the ground cover in washes is overstory Ambrosia del to idea 1.84 2.41 species that provided bedsites for deer (table 5). Acacia greggii 2·i4 1.51 Prosopis juliflora T 1.36 Ambrosia ambrosioides T 1.29 Deer Occurance in Washes Acacia constricta 1.30 T Texas Haplopappus larcifolius o T Condalia spathulata o T Of 750 deer observations only 40 (5.3%) Encelia farinosa o T occurred within a wash, and 29 (3.9%) within 30 m Fouguieria splendens o T of a wash. .fu:Q.lli ~ o T Krameria .ru:m o T Arizona ~spp. o T Opuntia leptocaulis o T Belmont Mountains.--Deer use of xeroriparian Simmondsia chinensis o T systems was highest in summer (83.3%) followed by Sphaeralcea spp. o T fall (82.2%) and spring (70.5%) (table 6). During the winter deer use of washes was 42.1%. Total % cover 31.27 39.11 Overall, 842 of 1180 (71.4%) deer were located in Diversity 2.01 2.24 washes (table 6).

King ~.--Over 99% of the deer locations in King Valley were in washes (table 7). The six 1 T = <1% cover) locations that were not in washes were either in

147 Table 5.--Percent cover of vegetation in 4 wash Table 7.--The number (and percent) of deer classes in King Valley, Arizona. locations in 4 wash classes in King Valley, Arizona •

~ n ..Q2. n Simple n C2 £i Other Av. width of wash 15.74 39.51 89.62 284.3 Av. % cover of vegetation 30.40 29.36 23.76 24.77 Females 47 184 172 62 5 Av. II drainages 1.0 3.2 6.93 12.95 (9.8) (39.1)(36.6)(13.2) ( 1.1) Av. It of species 7.5 9.05 9.32 10.75 Av. % of overstory cover 10.55 8.84 8.46 8.05 Males 32 44 67 28 1 (18.6) (25.6)(39.0)(16.3) (0.1) Hilaria rigid a 0.05 1.02 0.08 Atriplex polycarpa 0.28 0.94 0.11 0.56 Acacia~ 0.19 0.35 0.41 0.79 Prosopis julif:lora 0.30 0.10 0.03 0.52 In Arizona, most deer were located in washes. Krameria ~ 0.96 0.25 0.13 0.25 III both Arizona study areas the plant species Cercidium microphyllum 3.54 1.88 1.42 0.24 diversity was twice as high in the xeroriparian .Q... floridum 1.42 2.55 3.28 5.64 washes. Food and cover was scarce outside of Olneya tesota 5.10 3.96 3.32 0.81 these washes in King Valley and less abundant than Larrea tr1dentata 10.48 11 .89 11 .05 9.97 in washes in the Belmont Mountains. Desert mule Sphaeralcea SPp. 0.18 0.31 0.23 2.52 deer in Arizona may be selecting xeroriparian ~ andersQnii 3.60 2.85 2.56 3.47 washes because they provide more food, cover, and Ambrosia dumosa 3.12 1.18 0.65 0.16 travel lanes than the surrounding areas. Encelia farinQsa 2.57 2.94 1.67 0.55 Xeroriparian systems are an important part of Other species 0.86 1.28 1.09 1.38 desert mule deer habitat in xeric ranges.

Diversity (H') 2.10 2.12 1.93 2.03 LITERATURE CITED

Alcoze, T. M., and E. G. Zimmerman. 1973. Food agriculture fields or disturbed areas near habits and dietary overlap of two heteromyid agriculture at the south end of King Valley. rodents from the mesquite plains of Texas. J. Mammal. 54:900-908. DISCUSSION Anthony, R. G. , and N. S. Smith. 1977. Ecological relationships between mule deer Deer in BBNP are not as dependent upon and white-tailed deer in southeastern xeroriparian systems as deer in Arizona. In Arizona. Ecol. Monogr. 47:255-277. Texas, deer forage is abundant in the habitats Canfield, R. H. 1941. Application of the line adjacent to wash systems. Although the plant interception method in sampling range species composition of washes and adjacent vegetation. J. For. 39:388-394. habitats are not similar, both areas have Clark, E. D. 1953. A study of the behavior and relatively equal diversity, except in plant movements of the Tucson Mountain mule deer. associations with low plant densities. Deer use M.S. Thesis, Univ. Arizona, Tucson. 111 p. of these areas was minimal «1.0 deer/km2) Dice, L. R. 1943. The biotic provinces of North compared to plant associations with higher plant America. Univ. Michigan Press, Ann Arbor. densities (>1.5/deer km2) (Leopold 1984). The 78 p. greater plant densities and diversities in the Dickinson, T. G., and G. W. Garner. 1979. Home interwash regions in BBNP allows deer to find range use and movements of desert mule deer forage and cover in these areas instead of in in southwestern Texas. Proc. Ann. Conf. S.E. washes, as deer in Arizona must. 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 Apr-Jun Jul-Sep Oct-Dec Total

Habitat Wash Other Wash Other Wash Other Wash Other Wash Other

Occurrences 82 113 322 135 304 61 134 29 842 338

Percent occurrences 42.1% 70.5% 83.3% 82.2% 71.4% in washes

148 Dix, R. L. 1969. An application of the point­ bighorn sheep. Final Rept. 9-07-30-X069 to centered quarter method of the sampling of USDI/B.R. Phoenix, Arizona. grassland vegetation. J. Range Manage. Leopold, B. D. 1984. Ecology of desert mule deer 14:63-69. in Big Bend National Park, Texas. Ph.D. Johnson, R. R., S. W. Carothers, and J. M. Dissertation, Univ. Arizona, Tucson. 172 p. Simpson. 1981. A riparian classification ______, and P. R. Krausman. 1983. Plant system. p 375-382 in R. E. Warner, and K. M. communities of the lower desert shrubland in Hendrix, eds. California riparian systems: Big Bend National Park, Texas. Second ecology, conservation, and productive Chihuahuan Desert Symposium, Alpine, Texas. management. Univ. of California Press, In Press. Berkeley. 1035 p. Morista, M. 1959. Measuring of interspecific Koerth, B. H., Jr. 1981. Habitat use, herd association and similarity between ecology, and seasonal movements of mule deer communities. Mem. Fac. Sci. Kyrishu Univ., in the Texas Panhandle. M.S. Thesis, Texas Sere E. BioI. 3:65-80. Tech Univ., Lubbock. 103 p. Phillips, J. L. 1974. The annual behavioral Krausman, P. R., and E. D. Ables. 1981. Ecology cycle of desert mule deer (Odocoileus of the Carmen Mountains white-tailed deer. hemionus crooki) in relation to vegetative National Park Service Sci. Monogr. 15:1-114. use. M.S. Thesis, SuI Ross State Univ., Alpine, Texas. 60 p. ______, J. J. Hervert, and L. L. Ordway. Truett, J. C. 1972. Ecology of the desert mule 1984. Radio tracking desert mule deer and deer, Odocoileus hemionus crooki Mearns in bighorn sheep with light aircraft. pp. 115- southeastern Arizona. Ph.D. Dissertation, 118 in P. R. Krausman and N. S. Smith, eds. Univ. Arizona, Tucson. 64 p. Deer in the southwest: a workshop. School of Wallmo, O. C. 1981. Mule and black-tailed deer Renewable Natural Resources, Univ. of distribution and habitats. pp. 1-25 jn O. C. Arizona, Tucson, Arizona. Wallmo, ed. Mule and black-tailed deer of 1978. Forage relationships North America. Univ. Nebraska Press, between two deer species in Big Bend National Lincoln. 605 p. Park, Texas. J. Wildl. Manage. 42:101-107. Zar, J. H. 1974. Biostatistical analysis. ______, 1984. Impacts of the Central Arizona Prentice-Hall Inc., Englewood Cliffs, N.J. Project on desert mule deer and desert 620 p.

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