Preestablished Plant Influences on Antelope Bitterbrush (Purshia tridentata Pursh) Seedling Recruitment and Growth: Analysis of Species and Positional Effects Author(s): Daniel L Mummey, Lauren Stoffel and Philip W. Ramsey Source: Natural Areas Journal, 38(1):44-53. Published By: Natural Areas Association https://doi.org/10.3375/043.038.0106 URL: http://www.bioone.org/doi/full/10.3375/043.038.0106
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BioOne sees sustainable scholarly publishing as an inherently collaborative enterprise connecting authors, nonprofit publishers, academic institutions, research libraries, and research funders in the common goal of maximizing access to critical research. R E S E A R C H A R T I C L E ABSTRACT: We evaluated the influence of preestablished plant species distance, direction, and identity on antelope bitterbrush (Purshia tridentata Pursh) seedling establishment and biomass production. Antelope bitterbrush seeds were planted 10- and 20-cm away from the base of three preestablished plant species. We monitored seedling establishment and growth during and after two growing seasons. s Sowing antelope bitterbrush seeds 20-cm away from preestablished plant bases yielded 1.59 times greater seedling establishment than seeds sown 10-cm away, suggesting that established plants interfere with bitterbrush recruitment. Antelope bitterbrush seedling survival after 2 y of growth was greater than 96% Preestablished for all treatments, suggesting that early growth phases were the primary bottlenecks to establishment. Antelope bitterbrush forage production decreased with proximity to preestablished plants. After 2 y of Plant Influences growth, antelope bitterbrush biomass was almost 3 times greater for plants grown without preestab- lished plant neighbors or with a preestablished grass (Elymus elymoides Raf.) than with preestablished forb species (Dalea candida Michx. ex Willd. or Gaillardia aristata Pursh). Inoculating preestablished on Antelope plants with soil from native sites or arbuscular mycorrhizal fungi did not influence antelope bitterbrush establishment or growth. We suggest that plant trait complementarity and spatial relationships can be Bitterbrush used to design seeding strategies to increase antelope bitterbrush establishment and forage production. (Purshia tridentata Index terms: competition, facilitation, forage, mule deer, soil inoculation, spatial relationships
Pursh) Seedling INTRODUCTION 1956) and decreases forage production for wildlife (Sanderson et al. 1963). The Recruitment and Antelope bitterbrush (Purshia tridentata perceived need to limit competition during Pursh) is a shrub species that occurs in the antelope bitterbrush establishment presents Intermountain West from British Columbia, a quandary for restoration practitioners and Growth: Analysis Canada, to northern Mexico (Nord 1965; wildlife habitat managers. Establishment of Giunta et al. 1978; Clements and Young competitive plant cover is the only long- of Species and 2002). It is one of the most important term solution for invasive annual grass browse species for mule deer (Odocoileus control (Booth et al. 2003; Chambers et Positional Effects hemionus Raf.) and other large ungulates al. 2007), but antelope bitterbrush alone in the western United States (Clements is a poor competitor with winter annuals and Young 1997; Young and Clements (Young and Clements 2002). Planting 2002; Pierce et al. 2004). Many antelope antelope bitterbrush into the herbaceous Daniel L Mummey1,2 bitterbrush stands are in decline (Young perennial communities required to fill niche and Clements 2002). Altered fire regimes, space and suppress cheatgrass (McGlone overgrazing, invasive plant species, and et al. 2011) decreases antelope bitterbrush 1MPG Operations competition from herbaceous perennial establishment and forage production 19400 Lower Woodchuck Rd. species are considered the primary caus- (Sanderson et al. 1963). Seeding antelope Florence, MT 59833 es of antelope bitterbrush stand decline bitterbrush without competition leaves sites (Guenther and Wambolt 1993; Young and susceptible to weed invasion (Clements Clements 2002). Concerns about wildlife and Young 2002). Lauren Stoffel1 habitat loss have stimulated interest in Philip W. Ramsey1 establishing antelope bitterbrush through Knowledge of interspecific plant interac- seed or seedlings (Clements and Young tions could provide insights into ways to 2002). There are several barriers to es- increase shrub establishment and growth. tablishing shrub species in arid environ- Plant neighbor interactions range from s ments to meet restoration goals. Specific facilitative to competitive and vary with knowledge about the role of plant–plant growth stage (reviewed by Brooker et and plant–microbe interactions could lead al. 2008). Inhibition, in its many forms, to improved techniques and outcomes for is the most studied plant interaction, but 2 Corresponding author: arid shrub species establishment. facilitation can also be important. Exam- [email protected] ples of facilitation include microclimate Antelope bitterbrush seedlings and adults modification, changes in soil chemical and are sensitive to competition, especially physical structure, alteration of microbial competition from cheatgrass (Bromus symbiont and pathogen communities, and tectorum L.) and other winter annual influences on pollinators, seed dispersal Natural Areas Journal 38:44–53 grasses (Holmgren 1956). Competition agents, and plant defense guilds (Callaway impedes seedling establishment (Holmgren 1995). Reports of facilitation are most
44 Natural Areas Journal Volume 38 (1), 2018 common in arid environments (Brooker METHODS telope bitterbrush roots, both native plant et al. 2008). In the sagebrush steppe, for community sites hosted mature antelope example, Reisner (2010) reported that Wy- Study Site bitterbrush plants. Each soil had four AMF oming big sagebrush (Artemisia tridentata treatments: Claroideoglomus etunicatum Nutt. ssp. wyomingensis) facilitates bunch- This study took place on a private ranch in culture MT108-8, Claroideoglomus etu- grass establishment through microclimate the Bitterroot Valley of western Montana, nicatum culture MT109-7, steam-treated modification. There is also precedent in USA (46°40 42.11 N, 114°02 02.50 W). inoculum as a no-AMF control, and no the literature for interspecific facilitation Historical climate data for the area (PRISM inoculation. Both inoculants were origi- of antelope bitterbrush. Hall et al. (1999) Climate Group 2012) recorded an average nally sourced from Montana grasslands found that antelope bitterbrush seedling annual precipitation of approximately 35 and cultured by the International Culture emergence and survival was greater in cm and a mean annual temperature of 7 Collection of (Vesicular) Arbuscular My- plots containing bluebunch wheatgrass °C. Weather stations near our study site corrhizal Fungi (INVAM; West Virginia (Pseudoroegneria spicata Pursh) than in (https://www.mpgranch.com) recorded University, Morgantown). Inoculants were bare-soil plots or plots containing crested 18.7-cm precipitation in 2012 and 20.3- added at the time of planting by placing 3 wheatgrass (Agropyron cristatum L.) or cm total precipitation in 2013. Annual approximately 1-cm inoculum in a 1.5- cheatgrass. This study suggests that fa- temperature averaged 8.5 °C in 2012 and cm depression, adding three seeds, then cilitative plant interactions could increase 8.2 °C in 2013. covering with field soil. Plants were in the antelope bitterbrush establishment. greenhouse for 3 mo before transplanting them to our field site. Experimental Design Plant competitive relationships are influ- Our experimental site is a former agri- enced by interactions with soil microbial We used four different plant species in this cultural field. The site was fallow for 2 communities (Klironomos 2002). Plants experiment: an early season grass (squir- y prior to our study. Soil on the site has influence the growth of neighboring plants reltail; Elymus elymoides Raf.), a perennial sandy loam texture with a pH of 6.3. Weeds by changing soil communities. Inoculation legume (white prairie clover; Dalea can- were controlled with a systemic herbicide of plants with specific arbuscular mycor- dida Michx. ex Willd), a perennial forb in (glyphosate) before planting and by pulling rhizal fungi (AMF) species and whole the Aster family (blanketflower; Gaillardia thereafter. To prevent damage to experi- soil inoculum collected from diverse aristata Pursh), and antelope bitterbrush. mental plants by large animals, we installed plant communities could improve the The forb and grass species were selected a 2.5-m fence around the field. To prevent establishment of species in degraded soils because of broad differences in functional damage from small animals, we installed (Clements and Young 2000b; Verbruggen traits. Squirreltail is one of the first species a 0.75-m fine mesh (0.635 cm) wire fence et al. 2013). The benefit of inoculum may to become active after snowmelt in the inside the large animal fence. We capped spread to neighboring plants in degraded spring (USDA NRCS 2016). It remains the small animal fence with metal flashing soils, as demonstrated by Middleton and dormant much of the summer and becomes to prevent animals from climbing over the Bever (2012). active again in the fall when moisture is top. Small animals inside the exclosure sufficient. White prairie clover becomes were trapped before planting. To prevent We examined the influence of three dif- active mid-spring, and flowers from mid- small animal reestablishment, animal traps ferent preestablished native plant species to late summer (USDA NRCS 2016). It remained in the exclosure throughout the grows 0.6 to 0.9-m tall and has fine-textured on the establishment and vigor of antelope experiment. leaves. Blanketflower becomes active mid- bitterbrush. We evaluated the influence of spring and blooms late into the summer soil and AMF inoculants on antelope bit- We outplanted forbs and grasses in May (USDA NRCS 2016). It has coarse leaves 2011. Plant locations were randomized terbrush establishment and growth, and the and grows to a height of 0.7 m. All seeds in 19 rows. We used a 1.25-m minimum importance of seed positional effects—the were obtained from a commercial source separation distance between plants to distance and direction of antelope bitter- (Granite Seed, Lehi, Utah). decrease the potential for nontarget plant brush in relation to preestablished plants. interactions. Plants were watered during Our goal was to evaluate plant interactions We started 200 individuals of each forb and the first growing season to facilitate es- to improve antelope bitterbrush establish- grass species in a greenhouse. We filled tablishment. ment techniques. We hypothesized that (1) 49- cm3 pots (2.5 × 12 cm; Cone-tainers, the identity of preestablished plant species, Stuewe and Sons, Tangent, Oregon) with In fall 2011, we used a spatially stratified (2) the position of antelope bitterbrush surface soils (0–8 cm) collected from the design to sow 48 antelope bitterbrush seeds seeds relative to established plants, and (3) study site (see below) or from under each around each of 400 established plants the introduction of AMF and whole soil of two nearby undisturbed native plant and in 112 control sites with no prees- inoculum from native plant communities community sites (described in Lekberg et tablished plant (Figure 1). We seeded on would influence antelope bitterbrush estab- al. 2013). Although we did not attempt to all sides of established plants to evaluate lishment and forage production. collect soils directly associated with an- the importance of preestablished plant
Volume 38 (1), 2018 Natural Areas Journal 45 es on antelope bitterbrush height at each measurement time using one-way general linear models. Antelope bitterbrush height on each plot was averaged before analysis. Preestablished plant identity was used as the explanatory variable.
One-way general linear models were used to evaluate the influence of established plant identity on antelope bitterbrush growth seasonality. The percent of total antelope bitterbrush growth on each sam- ple date was used as the response variable and preestablished plant identity as the explanatory variable.
Differences in preestablished plant height and width in 2012 and 2013 were evalu- ated using one-way general linear models. Preestablished plant species identity was used as the predictor variable. Figure 1. Plot design. The preestablished plant is indicated by the filled circle in the center. Antelope bitterbrush seed locations are depicted by small circles. The inner seed rows are 10 cm, and outer rows Antelope bitterbrush biomass data was 20 cm, from the center of the preestablished plant. log-transformed before analysis to meet assumptions of normality. General linear models were calculated using the General species–facilitated differences in sunlight summer 2012. Seedling distance and di- Linear Models module of SPSS (ver. 20). and wind interception on antelope bitter- rection from each plant served as predictor Tukey’s HSD post hoc analyses were brush recruitment. After plant mortalities, variables. For this analysis, we consider conducted to evaluate pairwise differences. preestablished plant numbers included 130 antelope bitterbrush plants that were visible Binary logistic regressions were calculat- squirreltail, 95 white prairie clover, and and alive in summer 2012 to be established. ed using the Generalized Linear Models 175 blanketflower individuals. A single module of SPSS (ver. 20). seed was placed in a 1.25-cm depression Two-way general linear models were used to evaluate the influence of antelope at each point (Figure 1) and covered with RESULTS field soil. bitterbrush seed placement direction and distance from each preestablished plant Antelope Bitterbrush Establishment We measured preestablished plant height species on antelope bitterbrush biomass. and Survivorship and width each summer after maximum The average biomass of antelope bitter- yearly growth. Antelope bitterbrush height brush plants growing in each distance Sown antelope bitterbrush seeding es- was measured in spring, summer, and fall and direction on each plot served as the tablishment measured in summer 2012 beginning in the summer of 2012 and end- response variable. Direction and distance ranged from 2.70% for seeds planted ing in the spring of 2014. After observing from preestablished plants served as ex- around prairie clover, to 3.20% for seeds army cutworm (Euxoa auxillaris Grote) planatory variables. planted around blanketflower (Table 1). damage to preestablished forb species The average seedling establishment was in the spring of 2014, we harvested, air- To evaluate the importance of antelope 2.94% across all plots. Differences between dried, and weighed antelope bitterbrush bitterbrush plant distance from all preestab- lished plant species, we averaged antelope preestablished plant treatments were not aboveground biomass. 2 bitterbrush biomass data for plants growing significant (χ = 5.99; df = 3; P = 0.112). at 10 cm and at 20 cm away from each Statistical Analyses plot center. We analyzed the data using a Antelope bitterbrush growing without two-way general linear model with ante- preestablished plants had the lowest plant Binary logistic regression analyses were lope bitterbrush biomass as the response mortality (0.63%) in 2014 (Table 1). The used to examine the influence of established variable and distance and preestablished highest antelope bitterbrush mortality plant identity, direction from established plant identity as explanatory variables. (5.60%) occurred in plants grown with plant, and distance from established plant blanketflower (Table 1). Antelope bitter- on antelope bitterbrush establishment in We evaluated preestablished plant influenc- brush mortality between summer 2012
46 Natural Areas Journal Volume 38 (1), 2018 Table 1. Bitterbrush seeds planted, seedling emergence in summer 2012, and plants surviving at the end of the experiment in 2014.
sta lishe lant Antelo e itter rush s ecies See s lante erge Percent e erge Survive Percent ortalit o lant . . S uirreltail . . Prairie clover . . lan et lower . .
and spring 2014 averaged 4.15% for all Antelope Bitterbrush Growth Antelope bitterbrush grown 10 cm from treatments. preestablished plant bases had lower final Soil origin and AMF inoculation did not biomass than antelope bitterbrush grown significantly influence antelope bitterbrush Antelope bitterbrush establishment was 20 cm away (Figure 3 and Table 3). Di- biomass (F = 1.17 ; P = 0.311; data greater for seeds sown 20 cm from prees- (5, 2252) rection from preestablished plants did not not shown). Established plant species iden- tablished plants than 10 cm (Figure 2 and significantly influence antelope bitterbrush tity influenced antelope bitterbrush total biomass (Table 3). Interactions between Table 2). Direction from preestablished biomass. Antelope bitterbrush plants grown plant and direction*distance interactions distance and direction were not significant with prairie clover or blanketflower were for any treatment (Table 3). were not significant for any treatment smaller than plants grown with squirreltail (Table 2). Seed location had no influence or without a preestablished plant (Figure 3). Antelope bitterbrush height was greater for on antelope bitterbrush establishment in Antelope bitterbrush biomass was similar the no–established plant plots (Figure 2 for plants grown with squirreltail or without the no–established plant and preestablished and Table 2). a preestablished plant (Figure 3). squirreltail treatments than for plants grown with preestablished white prairie clover or blanketflower at all measurement times after summer 2012 (Figure 4). Preestab- lished plant identity changed the timing of antelope bitterbrush height gains (Figure 5). In the fall of 2012 and 2013, percent of total antelope bitterbrush height gains were greater for no–preestablished plant and squirreltail than when grown with either forb species. In contrast, antelope bitterbrush plants grown with either forb species exhibited greater percent of total height gain in summer 2012 and spring 2013 (Figure 5).
Preestablished Plant Growth
Blanketflower height was greater than white prairie clover in 2012 but not in 2013 (Figure 6a). Height of both forbs was greater than squirreltail in 2012 and 2013. Blanketflower width was greater than white prairie clover and squirreltail in 2012 (Figure 6b). In 2013, white prairie clover width was greater than blanketflower and Figure 2. The relative proportion of bitterbrush plants within plant treatments that established at 10- and 20-cm distances from plot centers. The dashed line indicates equal establishment. The symbols at squirreltail, while blanketflower width was the top indicate significant differences within treatment as determined by binary logistic regression. greater than squirreltail in 2013. Symbols directly above each bar indicate significant differences in establishment compared with the no–established plant treatment; ** and *** indicate significance at P < 0.01 and P < 0.001, respectively.
Volume 38 (1), 2018 Natural Areas Journal 47 P <0.01 χ . , P <0.01
Figure 3. Aboveground biomass of bitterbrush plants that established 10 and 20 cm from plot centers. χ . , Different letters above bars for preestablished plant treatments indicate significant differences (P < 0.05) in bitterbrush biomass between preestablished plant treatments as determined using a two-way general linear model; * and ** indicate significant (P < 0.05 and P < 0.01, respectively) within-treatment differences in bitterbrush biomass for plants growing 10 and 20 cm away from plot centers. Error bars P indicate standard error. <0.01
DISCUSSION imize antelope bitterbrush establishment. Seeding antelope bitterbrush into plant Wildlife habitat managers seed antelope interspaces or artificially opening niches in
bitterbrush to provide forage and cover dense herbaceous plant communities, for . , χ for large and small animals, but antelope example, may increase antelope bitterbrush bitterbrush survival and forage production establishment.
P after seeding is often low (Clements and
<0.01 Young 2000a). Satisfactory establishment Similar to herbaceous arid grassland spe- requires that the competitive environment cies (James et al. 2011), we found that early in seeded areas is conducive to seedling growth stages were the primary bottleneck establishment and growth. for establishment. Competition did not strongly influence antelope bitterbrush
Our results indicate that the proximity of survival after initial spring establishment χ antelope bitterbrush seeds to preestablished and antelope bitterbrush survival rates were plants influences antelope bitterbrush high regardless of established plant species.
P establishment. Antelope bitterbrush seeds were 1.59 times more likely to establish In addition to effects on antelope bit- if located 20 cm from the base of an terbrush establishment, distance from established plant (352 seedlings estab- preestablished plants influenced antelope
o lant S uirreltaillished) Prairie clover than if lan et lowerlocated 10 cm away All lants (221 bitterbrush forage production. Antelope seedlings established). This result suggests bitterbrush biomass production decreased
that competitive effects at 10-cm distance with proximity to preestablished plants, χ outweighed potential modification of seed- suggesting that alternating seed drill bed conditions by established plants that rows with herbaceous species to increase may have facilitated antelope bitterbrush the distance between seeded species, emergence. Antelope bitterbrush estab- as recommended by Monsen and Shaw lishment was similar for seeds sown 20 (1983), may be a way to increase antelope cm from established plants and for seeds bitterbrush forage production. However, sown in the no–established plant control, intraspecific competition can also be im- suggesting that seeds can be positioned portant. Clements and Young (2002) found DirectionDistanceDirection istance . , . , . . , . , . . . , . around . , . . , established . , . . . , plants , . . in . . , ways . . , that . max- that dense antelope bitterbrush emergence Table 2. Relationships between seed position and bitterbrush plant establishment. Significant relationships are depicted in bold.
48 Natural Areas Journal Volume 38 (1), 2018 and establishment resulted in high intra- expected to be less than with white prairie specific competition that affected growth clover or blanketflower. P
. . and flowering. <0.01 Our results indicate that the competitive Antelope bitterbrush size differences balance shifted differently over the grow- between preestablished plant species ing season depending on preestablished
All lants treatments were apparent early in the plant identity and phenology. Antelope experiment. Antelope bitterbrush neigh- bitterbrush is an evergreen species and can
boring the large forbs, white prairie clover remain active the entire growing season,
. , . , . , F or blanketflower, had only one-third the with pulses of growth in response to rain total growth of antelope bitterbrush plants (Loik 2007). Antelope bitterbrush plants neighboring our smallest established plant grown with early-growing squirreltail, or P . 0.0 . species, squirreltail. Antelope bitterbrush without an established neighbor, exhibited neighboring squirreltail had total growth greater height gains in the fall compared similar to the no–established plant treat- with plants grown next to either forb. ment. Antelope bitterbrush size differences Conversely, antelope bitterbrush grown were greatest the second growing season with either later-growing forb grew high- lan et lower when size differences between squirreltail er in the first summer and in the spring. and white prairie clover or blanketflower Although we did not measure antelope . , . , . , F treatments were the most pronounced. bitterbrush width, we suspect that differ- ences in preestablished plant aboveground
P Interactions between established plant morphology contributed to differences in . . . root distribution, phenology, and size may height gains. Plants grown next to large explain our results. Antelope bitterbrush neighbors may allocate more resources to develops a long taproot that reaches up height than width to capture light (Grime to 5.4 m (McConnell 1961), but has few 1966; Schwinning and Wiener 1998). No
Prairie clover shallow roots (McConnell 1961; Baker plants grew better than the no–established and Torrey 1979; but see Loik 2007). plant treatment, indicating that competitive
. , . , . , F White prairie clover is reported to have rather than facilitative interactions explain a coarse, non-fibrous root system with a the variation between treatments. strong woody taproot that is 1.7–2.0 m P
. 0.01 . deep (Weaver 1954). Blanketflower has a Although analysis of microbial communi- taproot supported by several large laterals ties is beyond the scope of this study, there arising near the soil surface (Coupland and are a number of potential explanations Johnson 1965). The main root branches of for why inoculants did not alter antelope
S uirreltail blanketflower penetrate to depths of at least bitterbrush performance (reviewed by 1.3–1.7 m (Coupland and Johnson 1965). Verbruggen et al. 2013). We expected that Squirreltail has a fibrous root system that former agricultural management on our F . , . , . , extends to a depth of ≥1 m (Reynolds and experimental plots selected for decreased Fraley 1989). Our results suggest that plant abundance and diversity of beneficial
P neighbors having shallow root systems are microbial taxa (Schnoor et al. 2011), but . . . less competitive with antelope bitterbrush substantive data is not available. Inoc- after antelope bitterbrush is established and ulation into an abundant, diverse AMF will make better candidates for antelope community may be less likely to increase
o lant bitterbrush companion species in resto- plant performance (Lekberg and Koide ration projects. 2005; Wagg et al. 2011). Inoculants, either from AMF cultures or native soils, may not
F . , . , . , Squirreltail is one of the first species to have included fungal and bacterial species initiate growth in the spring (Jones 1998), beneficial to antelope bitterbrush. The AMF well before white prairie clover and blan- symbiosis is highly variable, dependent ketflower (pers. obs.). Early-season growth upon the identity of the AMF and host of squirreltail may have created a temporal species involved, and dependent on local niche overlap that influenced antelope conditions (Johnson et al. 1997). Inoculants bitterbrush establishment. After antelope may be less well adapted to conditions in bitterbrush develops a deep root system, our former agricultural field than local Direction Distance Direction istance Table 3. Relationships between seed position and bitterbrush biomass. Significant relationships are depicted in bold. niche overlap with squirreltail would be communities and were excluded from the
Volume 38 (1), 2018 Natural Areas Journal 49 Figure 4. Antelope bitterbrush height recorded at each sample time for all treatments. Different letters above bars at each sample time indicate significant height differences (P < 0.05) at each sample time. Error bars indicate standard error. community. Clements and Young (2000a) did not examine soil microorganisms or these authors directly inoculated antelope found that inoculation of container stock root nodulation, lack of beneficial soil or- bitterbrush seedlings. Here, inoculants with soils collected from under antelope ganisms, specifically Frankia species, were may not have thrived in association with bitterbrush stands increased survivorship thought to inhibit uninoculated plants. We preestablished plants or spread to antelope after transplanting. Although these authors inoculated preestablished plants, whereas bitterbrush.
Figure 5. Antelope bitterbrush percent of total height at each measurement time. Different letters above bars indicate significant within-measurement time differences (P < 0.05). Error bars indicate standard error.
50 Natural Areas Journal Volume 38 (1), 2018 Developing weed-resistant plant communi- ties that provide desired ecosystem services is a goal of restoration ecology (Pokorny et al. 2005). Squirreltail, Sandberg blue- grass (Poa secunda J. Presl.), and other
shallow-rooted, early-season grasses have < 0.05). Error bars received recent attention as potential com- P petitors with invasive winter annual grasses (Jones 1998; Jones et al. 2010; McGlone et al. 2011; Phillips and Leger 2015). Established perennial grasses suppress invaders of western grasslands (Whitson and Koch 1998; DiTomaso 2000; Chambers et al. 2007), but the influence of different perennial grasses on the establishment and growth of antelope bitterbrush varies. In a field study, Monsen and Shaw (1983) found that Idaho fescue (Festuca idahoensis Elmer) cover had a negative relationship, and squirreltail a positive relationship, with antelope bitterbrush cover. We suggest that antelope bitterbrush can be sown with a species that is competitive with salient invaders of western grasslands without decreased forage production. Future work should examine antelope bitterbrush estab- lishment and forage production in mixed communities in the context of restoration seedings on multiple sites.
Interspecific plant interactions ranging from negative to neutral influenced ante- lope bitterbrush establishment and growth. The influence of neighboring plants on antelope bitterbrush growth was species specific. This shows that consideration of plant trait compatibility will help devel- opment of strategies to establish antelope bitterbrush in restoration settings. Careful selection of antelope bitterbrush compan- ion species could allow plant communities to be constructed that do not impede antelope bitterbrush growth. Planting antelope bitterbrush with small-statured, shallow-rooted perennial grass species may allow the construction plant communities with high forage production and resistance to weed invasion.
Our study identified that distance from, and the identity of, established neighboring plants is important to antelope bitterbrush growth and forage production. While we acknowledge that additional studies are needed to examine a broader range of com- panion species and their traits, our study Figure Figure 6. Preestablished plant height (a) and width (b) at maximum yearly growth in 2012 and 2013. Different letters above bars indicate significant within-year differences ( indicate standard error.
Volume 38 (1), 2018 Natural Areas Journal 51 suggests that a trait-based strategy for con- Lauren Shreading has a BA in biology from Clements, C.D., and J.A. Young. 2002. Re- structing plant communities could increase the University of Montana. She works in storing antelope bitterbrush: Management antelope bitterbrush ecosystem services. restoration and ecology research at MPG guidelines for overcoming the challenges of establishing antelope bitterbrush after a Our study examined interactions between Ranch. wildfire. Rangelands 24:3-6. established plants and antelope bitterbrush Coupland, R.T., and R.E. Johnson. 1965. seedlings. Future studies are needed that Philip W. Ramsey, PhD, is an ecologist Rooting characteristics of native grassland examine the influence of intraspecific and and general manager of MPG Ranch. His species in Saskatchewan. Journal of Ecology interspecific seed and seedling interactions research interests are in ecosystem process- 53:475-507. on antelope bitterbrush establishment and es and he has published on the influence DiTomaso, J.M. 2000. Invasive weeds in range- growth. Seed caching may be the primary of management practices on forest soils, lands: Species, impacts, and management. Weed Science 48:255-265. mechanism of antelope bitterbrush seedling factors allowing for the spread of invasive establishment (West 1968; Vander Wall weeds in grasslands, and nutrient flow Ferguson, R.B., and J.V. Basile. 1967. Effect of seedling density on bitterbrush survival. 1994) and some studies suggest that ante- between rivers and floodplain forests. In Journal of Range Management 20:380-382. lope bitterbrush benefits from intraspecific addition to research, he oversees the man- Giunta, B.C., R. Stevens, K.R. Jorgensen, and agement and operations of MPG Ranch, a seed and seedling interactions. Ferguson P.A. Plummer. 1978. Antelope bitterbrush: and Basile (1967) and West (1968) found 3800-ha conservation property in western An important wildland shrub. Publication that antelope bitterbrush seedlings growing Montana. 78-12. Utah State Division of Wildlife in clusters are more likely to establish Resources, Salt Lake City. Grime, J.P. 1966. Shade avoidance and shade than seedlings grown alone. Knowledge LITERATURE CITED of intraspecific and interspecific seedling tolerance in flowering plants. Pp. 187-207 interactions could lead to improved ante- in R.G. Bainbridge, G.C. Evans, and O. Baker, D., and J.G. Torrey. 1979. The isolation lope bitterbrush establishment strategies Rackham, eds., Light as an Ecological and cultivation of actinomycetous root nod- Factor. Blackwell Scientific, Oxford. (Madsen et al. 2012). ule endophytes. Pp. 38-56 in J.C. Gordon, Guenther, G.E., and C.L. Wambolt. 1993. C.T. Wheeler, and D.A. Perry, eds., Symbi- Characteristics of bitterbrush habitats that otic Nitrogen Fixation in the Management influence canopy cover and mule deer brows- of Temperate Forests: Proceedings of a ing. Journal of Environmental Management ACKNOWLEDGMENTS Workshop; 2-5 April 1979; Corvallis, OR. 36:175-181. Oregon State University, Forest Research Jeff Clarke, Mike McTee, Prairie Wolfe, Laboratory, Corvallis. Hall, D.B., V.J. Anderson, and S.B. Monsen. Ben Garret, and Kelley Laflamme are 1999. Competitive effects of bluebunch Booth, M.S., M.M. Caldwell, and J.M. Stark. wheatgrass, crested wheatgrass, and cheat- acknowledged for field assistance. Kelley 2003. Overlapping resource use in three grass on antelope bitterbrush seedling Laflamme is acknowledged for assisting Great Basin species: Implications for com- emergence and survival. Research Paper with data collection and organization. We munity invisibility and vegetation dynamics. RMRS-RP-16, USDA Forest Service, Rocky thank Charlie Clements and an anony- Journal of Ecology 91:36-48. Mountain Research Station, Ogden, UT. mous reviewer for comments that greatly Brooker, R.W., F.T. Maestre, R.M. Callaway, Holmgren, R.C. 1956. Competition between improved the manuscript. MPG Ranch C.L. Lortie, L.A. Cavieres, G. Kunstler, P. annuals and young bitterbrush (Purshia Liancourt, K. Tielbörger, J.M.J. Travis, F. tridentata) in Idaho. Ecology 37:370-377. generously supported this work. Anthelme, et al. 2008. Facilitation in plant James, J.J., T.J. Svejcar, and M.J. Rinella. 2011. communities: The past, the present, and the Demographic processes limiting seedling future. Journal of Ecology 96:18-34. recruitment in arid grassland restoration. Daniel L. Mummey earned his BA in micro- Callaway, R.A. 1995. Positive interactions Journal of Applied Ecology 48:961-969. biology at Eastern Washington University, among plants. Botanical Review 61:306-349. Johnson, N.C., J.H. Graham, and F.A. Smith. his MS in soil science at Washington State Chambers, J.C., B.A. Roundy, R.R. Blank, 1997. Functioning of mycorrhizal asso- University, and his PhD in soil science S.E. Meyer, and A. Whittaker. 2007. What ciations along the mutualism–parasitism and restoration ecology at the University makes Great Basin sagebrush ecosystems continuum. New Phytologist 135:575-585. of Wyoming. After graduating in 2004, he invasible by Bromus tectorum? Ecological Jones, T. 1998. Viewpoint: The present status worked as an assistant research professor Monographs 77:117-145. and future prospects of squirreltail research. in the Department of Biological Sciences Clements, C.D., and J.A. Young. 1997. A Journal of Range Management 51:326-331. at the University of Montana, Missou- viewpoint: Rangeland health and mule Jones, T., T. Monaco, and J. James. 2010. deer habitat. Journal of Range Management la. Dan’s research focuses on how soil Launching the counterattack: Interdisci- 50:129-138. plinary deployment of functional traits to structure, soil organisms, and plants de- Clements, C.D., and J.A. Young. 2000a. Ante- repair damaged intermountain rangelands. termine plant community composition and lope bitterbrush seedling transplant survival. Rangelands 32:32-37. ecosystem function. In Dan’s current role at Rangelands 22:15-17. Klironomos, J.N. 2002. Feedback with soil biota MPG Ranch, he develops and implements Clements, C.D., and J.A. Young. 2000b. Factors contributes to plant rarity and invasiveness methods to establish healthy native plant influencing survival of transplanted antelope in communities. Nature 417:67-70. communities in disturbed areas. bitterbrush seedlings. Rangelands 22:15-17. Lekberg, Y., S.M. Gibbons, S. Rosendahl, and
52 Natural Areas Journal Volume 38 (1), 2018 P.W. Ramsey. 2013. Severe plant invasions mountain Forest and Range Experiment bance as a determinant of arbuscular mycor- can increase mycorrhizal fungal abundance Station, Ogden, UT. rhizal fungal communities in semi-natural and diversity. The ISME Journal 7:1424- Nord, E.C. 1965. Autecology of bitterbrush grassland. Mycorrhiza 21:211-220. 1433. in California. Ecological Monographs Schwinning, S., and J. Weiner. 1998. Mech- Lekberg, Y., and R.T. Koide. 2005. Is plant 35:307-334. anisms determining the degree of size performance limited by abundance of arbus- Phillips, A.J., and E.A. Leger. 2015. Plastic asymmetry in competition among plants. cular mycorrhizal fungi? A meta-analysis of responses of native plant root systems to Oecologia 113:447-455. studies published between 1988 and 2003. the presence of an invasive annual grass. USDA NRCS. 2016. The PLANTS Database. New Phytologist 168:189-204. American Journal of Botany 102:73-84. Accessed from
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