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Home ranges of sympatric mule deer and white-tailed deer in Texas.

In Texas, geographic distributions of mule deer (Odocoileus hemionus) and white-tailed deer (O. virginianus) overlap in portions of the Trans-Pecos region, the western edge of the Edwards Plateau, and in the Texas Panhandle (Smith, 1987). White-tailed deer have become more abundant in areas previously considered to be occupied only by mule deer (W. F. Harwell and H. G. Gore, in litt.), and mule deer have decreased or disappeared entirely from some areas (Wiggers and Beasom, 1986). Amount of area used by female deer and their survival are of interest to private landowners and managers as hunting is a significant economic contribution in Texas (S. Lightwood, unpublished data). Income from hunting leases or other wildlife recreation can supplement or even exceed that from traditional domestic livestock (Butler and Workman, 1993). Managers may wish to implement management activities to benefit primarily white-tailed deer because of higher bag limits and longer hunting seasons. However, others may prefer to manage habitat to favor mule deer. Our objectives were to investigate differences in size of home range and degree of overlap of home ranges and core areas between the two species. Because allopatric female white-tailed deer in semi-arid and and regions tend to have smaller home ranges (Gallina et al., 1997) than allopatric female mule deer in similar environments (Dickinson and Garner, 1979; Hayes and Krausman, 1993; Relyea et al., 2000), we predicted that mule deer would have larger home ranges than white-tailed deer in west-central Texas. However, because these species are not territorial and have similar diets (Anthony, 1972; Krausman, 1978), we predicted that there would be overlap in home ranges. Other studies of sympatric deer have determined that the species maintain separate distributions, but these studies occurred in prairies of Montana (Wood et al., 1989) and grasslands of Colorado (Whittaker, 1995), where deer are subject to harsh winter conditions and are partially migratory.

MATERIALS AND METHODS--The study was conducted on five contiguous ranches (ca. 323 [km.sup.2] in total area) in the northwestern corner of Crockett County, Texas, on the western edge of the Edwards Plateau. Lower elevations were dominated by mesquite (Prosopis), creosotebush (Larrea tridentata), tarbush (Flourensis cernua) and prickly pear (Opuntia). Juniper (Juniperus) was the dominant woody species on mesas. Washes supported dense thickets of hackberry trees (Celtic occidentalis). Slopes supported xeriphytic plants such as yuccas (Yucca) and ocotillo (Fouquieiia splendens; Correll and Johnston, 1970). Livestock grazing, oil production, and hunting were ongoing on all ranches (Brunjes, 2004).

Topography consisted of broad, level plateaus, rolling hills, and steep canyons. Elevation was 700-915 m. Mean annual precipitation for 2000-2002 was 25 cm (average for 1963-1997 was 43 cm). Most rainfall occurred May-September; greatest amounts usually occurred during September. Average annual low temperature was 10[degrees]C and average annual high was 26[degrees]C. In winter, daily temperatures ranged from a minimum of -1[degree]C to a maximum of 16[degrees]C, and in summer, 16-32[degrees]C (National Oceanic and Atmospheric Administration, 2000, 2001, 2002; http://www.ncdc.noaa.gov).

We estimated densities of deer with the aid of a helicopter during February 2001. The pilot and one observer surveyed the study area by flying adjacent belt transects ca. 200 m wide at an altitude of ca. 30 m. A Garmin Geographic Positioning System unit (Garmin Ltd., Olathe, Kansas) was used to plot transects and maintain parallel flight lines. Surveys began at 0800 h and ended at 1700 h; the entire study area was surveyed in 5 days. We counted deer on both sides of the helicopter and used composition of group, characteristics of antlers, and location to determine if deer had been counted previously (DeYoung, 1985). We classified deer to species, sex, and age (juvenile or adult). We calculated number of deer per unit area and ratio of males to females and juveniles to adult females for the study area.

On 2-3 February 2000 and 30 January 2001, personnel from Holt Helicopters (Uvalde, Texas) randomly captured deer with a net-gun fired from a helicopter following the protocol outlined by Krausman et al. (1985). We recorded sex and condition of each animal and estimated age of deer by toothwear and replacement (Severinghaus, 1949; Robinette et al., 1957). We fitted each deer (both sexes) with a numbered plastic eartag and a 500-g radiocollar equipped with a motion-sensitive mortality switch (Telonics, Mesa, Arizona).

We conducted radiotracking with a truck-mounted, null-peak system consisting of two 4-element Yagi antennas mounted on a rotating, telescoping, boom in the truck-bed. We located deer using methods of White and Garrott (1990) that recommended [less than or equal to]20 min between first and last azimuth. One to two observers participated. We used the program LOAS (Ecological Software Solutions, Sacramento, California) to determine locations of deer. We located collared females >4 times/month during January-August 2000-2002 to estimate size of home ranges. Deer were not located during hunting season (September-mid january) in compliance with requests of landowners. We rotated timing of relocations sequentially through 3 time blocks (0500-1059, 1100-1659, 1700-2400 h). We determined telemetry error following recommendations of White and Carrot (1990) by using collars in known locations and then located by individuals that did not know where the transmitter was located. We used the Animal Movement extension for ArcView (Hooge and Eichenlaub, 2000) to calculate size of home ranges using the 95% and 50% fixed-kernel and minimum-convex-polygon methods. We calculated size of home range using the minimum-convex-polygon method for 13-17 mule deer and 14-19 white-tailed deer/season and year for comparison to previously published studies based upon a minimum of 30 locations/season, but used only size of home ranges generated with 95% and 50% fixed-kernel methods for further analysis. We used size of home ranges determined using the 50% fixed-kernel method as an approximation of the core area of each animal (Loveridge and Macdonald, 2003). Home ranges were calculated for winter-spring, which encompassed the pregnancy period (January April) and summer, the fawning season (May-August). Size of home ranges and core areas were calculated for each season and year for individuals having >30 locations in that season.

We used ArcView software to identify the polygon created when core areas or home ranges overlapped. Each overlapping polygon was assigned as mule deer:mule deer, mule deer:white-tailed deer, or white-tailed deer:white-tailed deer. If [greater than or equal to]1 location of either animal occurred within that overlapping polygon, we calculated an overlap index using the following ratio:

[(ny +[n.sub.2])/([N.sub.] +[N.sub.2])] x 100

where [n.sub.1] and [n.sub.2] refer to respective number of locations for each deer within the overlapping polygon, and Ni and [N.sub.2] refer to the respective total number of locations recorded for each deer used to calculate size of home range (Chamberlain and Leopold, 2002). We used this procedure to calculate indices of overlap for core areas. We also calculated indices of overlap of home ranges of individual deer for spring and summer to quantify seasonal differences. We did not calculate interspecific indices of overlap for 2000 because only three instances of interspecifyc overlap in home range were detected. This is likely due to the fact that in 2000 we endeavored to spread our capture effort throughout the entire study area. During 2001, we concentrated our efforts in the center of the study area, resulting in increased detection of overlapping core areas and home ranges among collared animals.

We used Levene's test to check for homogeneity of variance for all comparisons and examined residuals for normality (Zar, 1999; Bryce et al., 2002). If Levene's test was insignificant and data were distributed normally, we used analysis of variance ([alpha] = 0.05) to compare mean size of home ranges between years and ages within species and between species, and to test for interactions (White and Garrott, 1990). When Levene's test was significant, indicating inequality of variances, we used Kruskal-Wallis for one-way comparisons, and Friedman's test for two-way comparisons (Zar, 1999). Because of unequal samples, Fisher's LSD test was used for separation of means in comparisons of overlap.

RESULTS-Estimated densities of deer during the helicopter survey in February 2001 were 2.4 mule deer/[km.sup.2] and 1.6 white-tailed deer/[km.sup.2]. Number of adult females per adult male in 1999, prior to initiation of the study, was 1:3 for mule deer and 1:7 for white-tailed deer; the ratio in 2001 was 1:3 for both species. Number of fawns per adult female in 1999 was 0.5:1 for mule deer and 0.4:1 for white-tailed deer; in 2001, the ratio was 0.2:1 for both species.

We captured and fitted 40 females of each species with radiocollars in January 2000. In January 2001, we captured and collared an additional 13 white-tailed deer and 10 mule deer. Mean age at capture was 4.5 years for both species (range for mule deer = 2.5-6.5; range for white-tailed deer = 1.5-7.5). Average bearing error was [+ or -]7[degrees] based on triangulated locations of collars in known locations. Mean size of home ranges determined by the minimum-convex-polygon method were similar between species in both seasons (Table 1).

Mean size of core areas determined by the 50% fixed-kernel method did not differ among seasons across years for either species (mule deer: [F.sub.5] = 1.28, P = 0.28; white-tailed deer: [F.sub.5] = 1.05, P = 0.39). Size of core areas between seasons was averaged across years within species to compare spring and summer (Table 1). Mean size of core areas in spring determined by the 50% fixed-kernel method was greater than size of core areas in summer for white-tailed deer ([F.sub.1] = 5.18, P = 0.03), but not for mule deer ([F.sub.1] = 0.79, P = 0.38). Mean size of core areas determined by the 50% fixed-kernel method was not different between mule deer and white-tailed deer for spring ([F.sub.1] = 0.08, P = 0.78) or summer ([F.sub.1] = 3.59, P = 0.06).

Mean size of home range determined by the 95% fixed-kernel method did not differ among seasons across years for either species (mule deer: [F.sub.5] = 0.70, P = 0.62; white-tailed deer: [F.sub.5] = 1.74, P = 0.13; Table 1). Mean size of home range determined by the 95% fixed-kernel method for spring was greater than that in summer for white-tailed deer ([F.sub.1] = 8.50, P < 0.01), but not for mule deer ([F.sub.1] = 1.56, P = 0.21). Within seasons, mean size of home range determined by the 95% fixed-kernel method was not different between mule deer and white-tailed deer for spring ([F.sub.1] = 1.25, P = 0.27) or summer ([F.sub.1] = 3.57, P = 0.06).

Within species, core areas in summer partially overlapped core areas in spring for individual deer during all years (Table 2). Indices of overlap were not different among years ([F.sub.1] = 1.01, P = 0.37) or between species ([F.sub.2] = 0.01, P = 0.92), nor was there a species-by-year interaction ([F.sub.2] = 0.97, P = 0.38). Both species exhibited greater individual fidelity in home range determined by the 95% fixed-kernel method within each year. However, as with core areas, indices of overlap were not different among years ([F.sub.1] = 0.85, P = 0.43) or between species ([F.sub.2] = 0.18, P = 0.67), nor was there a species-by-year interaction ([F.sub.2] = 0.91, P = 0.41).

Core areas and home ranges of individual animals for spring and summer also overlapped across years within seasons (Table 3). The index of overlap for core areas from spring to spring was greater for mule deer than for white-tailed deer ([F.sub.1] = 4.29, P = 0.04). Overlap in core areas from summer to summer also was greater for mule deer ([F.sub.1] = 9.60, P < 0.01). However, overlap of home ranges in spring and summer were not different across years ([F.sub.1] = 2.57, P = 0.12 and [F.sub.1] = 3.25, P = 0.08, respectively).

We observed instances of interspecific and intraspecific overlap of home ranges and core areas; however, differences among mule deer: mule deer, mule deer:white-tailed deer, or white-tailed deer:white-tailed deer occurred only in core areas (Table 4). In spring 2002, intraspecific overlap was greater than inter-specific overlap for both species (x22 = 10.35, P < 0.01). With the exception of summer 2001, interspecific overlap tended to be lower than interspecific overlap during both seasons. Degree of interspecific overlap did not differ among seasons or years for either species ([F.sub.2] = 0.48, P = 0.69), but they were different among mule deer:mule deer, mule deer:white-tailed deer, or white-tailed deer:white-tailed deer ([F.sub.2] = 3.03, P = 0.04); there was no season and year interaction for mule deer:mule deer, mule deer:white-tailed deer, or white-tailed deer:white-tailed deer ([F.sub.6] = 1.67, P = 0.13). Overlap in home range determined by the 95% fixed-kernel method was similar among mule deer:mule deer, mule deer:white-tailed deer, or white-tailed deer:white-tailed deer across all seasons. There was no difference in indices of overlap of home ranges among seasons ([F.sub.2] = 0.51, P = 0.68) or mule deer:mule deer, mule deer:white-tailed deer, or white-tailed deer: white-tailed deer ([F.sub.2] = 0.74, P = 0.48), nor was there a season and year interaction ([F.sub.6]= 0.64, P = 0.70).

DISCUSSION--Because we were unable to track deer during the breeding season, we may have underestimated size of home range for the year. Our results did not support our initial predictions that the sizes of home ranges would differ and that overlap would be considerable. According to competition theory, species with similar life-history traits should partition resources when they are sympatric if coexistence is to occur (Hardin, 1960). Differences in preference and use of forage do not appear to be the mechanism facilitating coexistence of these species (Hill and Harris, 1943; Allen, 1968; Martinka, 1968; Krausman, 1978), so some other resource (e.g., space) must be driving resource partitioning, at an unknown scale. Equivalent sizes and overlap of home range suggests both species exist on the same forage without partitioning, particularly during periods of low availability of forage. Rainfall during our study was 18 cm below average; drought may have narrowed any difference in size of home range between species. Because of their larger body mass, mule deer should require larger home ranges than sympatric white-tailed deer, but productivity of habitat appears to have a greater impact on actual size of home range of ungulates (Relyea et al., 2000). Home ranges tend to be larger as habitats become more xeric (Wood et al., 1989); however, female mule deer in this study had smaller home ranges than mule deer in other semi-arid and arid regions. In a sympatric area of Montana, average size of home range of non-migratory female mule deer was 6.30 [+ or -] 0.61 km2. Similarly, home ranges were smaller than those reported for female mule deer in western Arizona (daytime mean = 32.3 [km.sup.2], night = 25.5 [km.sup.2]; Hayes and Krausman, 1993) and southwestern Arizona (121 km2; Rautenstrauch and Krausman, 1989). However, estimates from this study were comparable to those from a sympatric area of southwestern Texas (mean = 3.8 [km.sup.2]; Dickinson and Garner, 1979). Size of home range of white-tailed deer in our study was similar to estimates determined using the minimum-convex-polygon method for white-tailed deer in northeastern Mexico (2.06 [+ or -] 0.13 [km.sup.2]; Gallina et al., 1997), but were smaller than those of white-tailed deer in a sympatric area of Montana (33.48 [+ or -] 6.22 km2; Wood et al., 1989). Small home ranges may indicate that densities are relatively high on our study area, possibly due to lack of predators and low hunting pressure, as high densities of ungulates have been correlated negatively with size of home range in ungulates (Marshall and Whittington, 1969). Furthermore, interspecific and interspecific competition tend to compress size of home range in ungulates (Courtois et al., 1998).

The high degree of interspecific overlap in home range or when it did not occur indicated that habitat partitioning may have occurred on a finer temporal or spatial scale than can be detected by home-range-level analyses. Inter-specific overlap during summer was greater during 2001 when spring rainfall was below normal, and decreased in 2002 when spring rainfall and subsequent production of forage were average. That interspecific overlap in home range was less than interspecific overlap in spring, suggests that the species segregate to a greater extent when resources are more abundant. Preferences for forage by both species became more divergent during droughts in Arizona, which may permit greater spatial overlap during drought (Anthony, 1976) because if diet is more diverse deer would cover larger areas. It is possible that competition for forage forced both species to forgo normal spatial avoidance during dry periods. Overlap in core area provides a greater potential for competition between species and conspecifics (Wauters and Dhondt, 1985). Greater avoidance of core areas of other species compared to conspecifics may indicate that interspecific competition influenced spatial distribution of individual deer more than did interspecific competition. Both species appeared to maintain home ranges within the same general area during both years, suggesting spatial coexistence was stable and neither species actively drove the other out of the area. However, white-tailed deer showed more tendency to shift home range between seasons, similar to sympatric female white-tailed deer in Montana, which frequently shifted home ranges in consecutive years (Wood et al., 1989). Competition from both mule deer and conspecifics may be the cause of shifts among seasons, as adult deer shift core areas in search of increased resources or to avoid competitors (Lesage et al., 2000).

Avey et al. (2003) indicated that there was habitat separation between species, suggesting that managers might be able to manage habitat for both species. However, the high degree of overlap in home range that we observed suggests that habitat management to primarily benefit only one species may be difficult to conduct on a large scale (e.g., an entire ranch). These species did not appear to maintain separate distributions on a home-range scale despite similarities in life history and selection of forage that suggest such separation might be necessary for long-term coexistence. Finer-scale selection of habitat may be the driving mechanism behind coexistence of both species in this area and warrants further investigation.

We thank C. Anderson, J. Brunjes, S. Dempsey, B. Hudgens, S. Petersen, R. Philips, and the L. D. Clark family for logistic support and field assistance. R Carrera provided the Spanish translation. Funding and support for this research was provided by Texas Parks and Wildlife Department, Rob and Bessie Welder Wildlife Foundation, and the West Texas and Houston chapters of Safari Club International. This is College of Agricultural Sciences and Natural Resources technical publication T-9-1137.

Submitted 15 August 2007. Accepted 16 September 2008.

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KRISTINA J. BRUNJES, WARREN B. BALLARD, MARY H. HUMPHREY, FIELDLING HARWELL, NANCY E. MCINTYRE, PAUL R. KRAUSMAN, AND MARK C. WALLACE

Department of Natural Resources Management, P.O. Box 42125, Texas Tech University, Lubbock, TX 79409 (KJB, WBB, MCW)

Texas Parks and Wildlife Department, Sonora, TX 76950 (MHH)

Texas Parks and Wildlife Department, Kerrville, TX 78028 (FH)

Department of Biological Sciences, Texas Tech University, Lubbock, TX 79409 (NEM)

School of Natural Resources, University of Arizona, Tucson, AZ 85721 (PRK)

* Correspondent. warren. ballard@ttu.edu

Associate Editor was Troy L. Best.
TABLE 1--Size of seasonal home ranges ([km.sup.2]) determined using
the minimum-convex-polygon (MCP), and 95% fixed-kernel methods, and
size of seasonal core areas ([km.sup.2]) determined using the 50%
and 95% fixed-kernel method for female mule deer (Odocoileus
hemionus) and white-tailed deer (O. virginianus) in west-central
Texas during spring and summer, 2000-2002.

Size of home range (MCP) Year Season n

Mule deer 2000 Spring 13
 Summer 14
 2001 Spring 15
 Summer 15
 2002 Spring 17
 Summer 15
 Mean seasonal Spring 17
 Summer 15
 Annual 15
White-tailed deer 2000 Spring 14
 Summer 19
 2001 Spring 15
 Summer 14
 2002 Spring 16
 Summer 17
 Mean seasonal Spring 16
 Summer 19
 Annual 16

Size of core areas (50% kernel)

Mule deer 2000 Spring 13
 Summer 14
 2001 Spring 15
 Summer 15
 2002 Spring 17
 Summer 15
 Mean seasonal Spring 17
 Summer 15
 Annual 15
White-tailed deer 2000 Spring 14
 Summer 19
 2001 Spring 15
 Summer 14
 2002 Spring 16
 Summer 17
 Mean seasonal Spring 16
 Summer 19
 Annual 16

Size of home range (95% kernel)

Mule deer 2000 Spring 13
 Summer 14
 2001 Spring 15
 Summer 15
 2002 Spring 17
 Summer 15
 Mean seasonal Spring 17
 Summer 15
 Annual 15

Size of home range (MCP)

White-tailed deer 2000 Spring 14
 Summer 19
 2001 Spring 15
 Summer 14
 2002 Spring 16
 Summer 17
 Mean seasonal Spring 16
 Summer 19
 Annual 16

Size of home range (MCP) Mean SE

Mule deer 1.68 0.17
 1.88 0.20
 1.26 0.21
 1.28 0.21
 1.76 0.24
 1.30 0.16
 1.28 0.14
 1.16 0.11
 2.30 0.19
White-tailed deer 1.46 0.11
 1.53 0.08
 1.45 0.20
 1.20 0.25
 2.37 0.30
 1.12 0.21
 1.47 0.17
 0.92 0.11
 2.25 0.21

Size of core areas (50% kernel)

Mule deer 0.88 0.25
 0.84 0.24
 0.80 0.17
 0.58 0.23
 0.55 0.11
 0.42 0.03
 0.73 0.10
 0.61 0.09
 0.51 0.08
White-tailed deer 0.86 0.47
 0.42 0.08
 0.77 0.16
 0.44 0.07
 0.72 0.10
 0.41 0.09
 0.78a 0.16
 0.42b 0.05
 0.42 0.06

Size of home range (95% kernel)

Mule deer 3.52 0.63
 3.37 0.90
 3.29 0.60
 2.87 0.39
 3.38 0.48
 2.26 0.23
 3.90 0.32
 2.82 0.32
 2.47 0.29

Size of home range (MCP)

White-tailed deer 3.94 2.24
 1.89 0.34
 4.30 0.88
 2.52 0.49
 4.67 0.60
 1.94 0.40
 4.32a 0.77
 2.08b 0.23
 1.77 0.26

TABLE 2--Seasonal fidelity (mean indices of overlap) within years in
core areas ([km.sup.2]) calculated using the 50% fixed-kernel method
and in home ranges ([km.sup.2]) determined using the 95% fixed-kernel
method for female mule deer (Odocoileus hemionus) and white-tailed
deer (O. virginianus) in west-central Texas, 2000-2002.

 Mule deer White-tailed deer

Year Mean SE n Mean SE n

Size of core areas
2000 30.80 9.98 7 15.38 9.58 9
2001 30.44 6.51 14 31.61 7.06 14
2002 19.59 5.09 15 25.54 6.38 17
All years 25.99 3.82 36 25.38 4.25 40

Size of home ranges

2000 69.36 6.34 7 58.76 6.71 9
2001 70.38 6.14 14 72.03 3.37 14
2002 66.06 4.24 15 69.62 3.81 17
All years 68.38 3.15 36 68.02 2.57 40

TABLE 3--Mean indices of overlap in core areas ([km.sup.2])
calculated using the 50% fixed-kernel method and in home
ranges ([km.sup.2]) determined using the 95% fixed-kernel
method for individual female mule deer (Odocoileus hemionus)
and white-tailed deer (O. virginianus) in west-central Texas,
spring and summer 2000-2002. Means followed by different
letters across rows were different at [alpha] = 0.05.

 Mule deer White aid deer

Season Mean SE n Mean SE n

Size of core areas

Spring--spring 32.19a 5.51 9 16.60b 5.05 25
Summer--summer 26.81a 4.72 19 9.53b 3.29 25

Size of home ranges

Spring--spring 58.45 6.63 19 42.87 6.81 25
Summer--summer 59.75 7.03 19 41.44 7.06 25

TABLE 4--Mean indices of overlap in core areas ([km.sup.2])
calculated using the 50% fixed-kernel method and in home
ranges ([km.sup.2]) determined using the 95% fixed-kernel
method for female mule deer (Odocoileus hemionus) and
white-tailed deer (O. virginianus) in west-central Texas,
2000-2002. Indices were compared with and between species.
Means followed by different capital letters across rows,
and different lower-case letters within columns, were
different at [alpha] = 0.05.

 Mule deer: mule deer

Year Season Mean SE n

Size of core area

2001 Spring 10.52 3.81 19
 Summer 6.11 3.4 14

2002 Spring 14.89A 5.53 21
 Summer 10.01 4.8 14

Combined Spring 12.81A 3.4 40
 Summer 8.06 2.9 28

Size of home range

2001 Spring 36.33 5.21 19
 Summer 34.7 8.37 14

2002 Spring 34.04 4.75 21
 Summer 34.35 6.36 14

Combined Spring 35.12 3.47 40
 Summer 34.52 5.16 28

 White-tailed deer: white-tailed deer

Year Season Mean SE n

Size of core area

2001 Spring 16 5.77 22
 Summer 6.22 3.03 26

2002 Spring 14.86A 4.47 30
 Summer 15.96 6.43 14

Combined Spring 15.34A 3.52 52
 Summer 9.63 3.03 40

Size of home range

2001 Spring 34.76 7.03 22
 Summer 28.73 5.36 26

2002 Spring 38.52 5.11 30
 Summer 45.24 5.94 14

Combined Spring 36.93 4.15 52
 Summer 34.51 4.2 40

 Mule deer: white-tailed deer

Year Season Mean SE n

Size of core area

2001 Spring 5.54ab 1.91 35
 Summer 10.44a 3.52 26

2002 Spring 0.77bB 0.54 31
 Summer 8.82a 3.88 12

Combined Spring 3.30B 1.08 66
 Summer 9.93 2.68 38

Size of home range

2001 Spring 30.96 4.01 35
 Summer 33.51 5.73 26

2002 Spring 27.51 3.61 31
 Summer 36.08 7.74 12

Combined Spring 29.34 2.71 66
 Summer 34.32 4.56 38
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Article Details
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Author:Brunjes, Kristina J.; Ballard, Warren B.; Humphrey, Mary H.; Harwell, Fieldling; McIntyre, Nancy E.;
Publication:Southwestern Naturalist
Article Type:Report
Geographic Code:1USA
Date:Sep 1, 2009
Words:5270
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