Seven plants native to the moist habitats of the pine savannas, woodlands, and Hillside Bog natural area at the Crosby Arboretum, Picayune, MS, were evaluated under laboratory and nursery conditions to determine seed germination percentage, optimal germination temperature, and the effect of substrates on germination. These native plants include: titi (Cyrilla racemiflora L.), buckwheat tree (Cliftonia monophylla Britt.), flameflower (Macranthera flammea (Bartr.) Pennell), deertongue (Carphephorus odoratissimus (Gmel.) Herb. var. odoratissimus), pink coreopsis (Coreopsis nudata Nutt.), tall ironweed (Vernonia angustifolia Michx.), and swamp bay (Persea palustris (Raf.) Sarg.). Laboratory experimentation concluded with germination and determination of optimal temperature regimes. Tall ironweed had the highest rate of success in the nursery. Black Kow compost had suboptimal performance compared to Sunshine Mix 1 and pine bark / sand under nursery conditions. Several of the species tested had minimal germination and require further research to optimize germination and nursery growth.

Temperate grasslands and the services they provide are threatened with severe degradation from human-driven land use changes. Among the worst affected services is pollinator support with grassland degradation contributing to the global decline in insect abundance due to habitat loss and a lack of floral resources. This has prompted conservation organizations to support pollinator conservation on working landscapes by increasing floral resources, but gaps remain in the consistent establishment of native forbs in intensively managed agricultural areas. We evaluated factors that influence native forb establishment during seed-based enrichment planting of tall fescue-dominated cattle pastures in two separate experiments: one testing a range of site preparation treatments with different seasons of sowing and comparing their effects on tall fescue suppression and seeded native plant establishment and the other investigating the effects of seed rate and pre-seeding cold stratification on native forb establishment on separate plots. For the site preparation experiment, we observed a mean target plant density of 0.12 target plants per m2 (SD = 0.247) The greatest target plant stem density (P < 0.0001) and species richness (P < 0.001) was in plots treated with a 2% glyphosate solution and sown with native seeds in early summer with the next five best treatments composed solely of fall sown replicates. For the seed and stratification experiment, we observed a mean target plant density of 88 target plants per m2 (SD = 73.9). Higher seeding resulted in greater target plant abundance in plots (P < 0.0001) with a seed rate of 56 kg/ha-1 resulting in almost three times as many target plants compared to 2.24 kg/ha-1. Pre-seeding stratification resulted in an increase in target plant abundance (P < 0.01). Target species richness was consistent between treatment levels. Results suggest that native forb establishment can be enhance by eliminating pasture grasses prior to seeding and the use of high seeding rates sown in the fall or using stratified seed. / Master of Science / Temperate grasslands and the services they provide are threatened with severe degradation from human-driven land use changes. Among the worst affected services is pollinator support with grassland degradation contributing to the global decline in insect abundance due to habitat loss and a lack of floral resources. To reverse this decline, conservation groups are encouraging the use of native plants throughout the landscape especially on farms and ranches to provide more resources for insect pollinators. One exciting opportunity exists in planting wildflowers into tall fescue-dominated cattle pastures that occupy millions of hectares of land in the Southeastern United States to provide food for pollinating insects. However little information exists on how to successfully establish wildflowers as much expertise is based on work done in the tallgrass prairie region of the Midwest. This study's goal was to investigate what control wildflower establishment by evaluating the success of an existing establishment experiment testing several site preparation techniques and different sowing seasons. A separate experiment was set up looking at the effect different seed rate and cold moist stratification had on establishment success of wildflowers. For the site preparation experiment, establishment was low for all treatments with a mean target plant density of 0.12 target plant per m2 (SD = 0.247). Summer sown 2% glyphosate had the highest wildflower richness and abundance at 0.35 target plants per m2 (SD = 0.247) and fall sown treatments were found to have higher sown wildflower abundance and richness than summer sown treatments. For the seed and stratification experiment, we observed a mean target plant density of 88 target plants per m2 (SD = 73.9). Target plant abundance did change between treatment levels with the highest and second highest seed levels yielding nearly three times and twice as many sown wildflowers as the lowest treatment respectively. Stratification resulted in an increase in sown wildflower abundance and sown wildflower richness did not differ significantly between treatment levels. Results suggest that native forb establishment can be enhance by eliminating pasture grasses prior to seeding and the use of high seeding rates sown in the fall using stratified seed.

This study had two goals: first, to establish a need to use native plant materials for planting and revegetation of highway right of ways in Utah; and secondly, to develop a list of potential native plants sui table for hi.ghway planting in Utah. To accomplish these two goals, three steps were completed. Correspondence was exchanged with officials of other state highway departments to determine their attitudes concerning the use of native plants for highway planting. Second, a case study was completed on two sections of the Interstate Highway system in the Weber-Davis area of Utah. This was done to document the present planting practices of the Utah Department of Transportation. The survival rate of the plants planted by Utah Department of Transportation was determined to be moderate to low, while native species have revegetated and were surviving without special maintenance. It was determined that there was a need to utilize native plants for highway planting in Utah. Third, a list of native plants was developed to provide a potential list of species suitable for highway planting and revegetation.

No description available.

Thesis (M. Appl. Sc.) -- Lincoln University, 2008. / Also available via the World Wide Web.

Invasive species are generally regarded as detrimental to native communities because they cause increased competition and community structure alterations. There is therefore a critical need to understand the ecological processes underlying the establishment and spread of invasive species. While most studies to date have focused on the role of competition in species invasions, trophic dynamics may also play a fundamental role in the establishment and spread of non-natives, especially in cases when a non-native species experiences differential predation pressure relative to a native competitor. Herein I explore the potential for differential granivory pressure by a native rodent (Heermann’s kangaroo rat, Dipodomys heermanni arenae) on native shrubs and an invasive plant (Veldt grass, Ehrharta calycina). Veldt grass, a perennial tufted grass native to South Africa and introduced to California in 1929, is highly invasive, and the shift of native coastal dune scrub to a grassland, dominated by Veldt grass, is considered one of the factors that led to the decline of the federally endangered Morro Bay kangaroo rat. However, kangaroo rats are largely graminivores (consume grass seed) and are known to consume invasive grasses and other plants. Differential seed preferences for native and Veldt seed were examined by placing feeding stations containing each seed type in habitats dominated by either native plants or Veldt grass. Each feeding station was monitored using motion-activated game cameras and the amount of each seed type collected by nineteen individually-marked, wild kangaroo rats was documented. These marked kangaroo rats were monitored both in native and Veldt grass habitats, allowing for the testing of habitat origin (Native vs. Veldt), sex (male or female) and seed type on the amount of seed taken. Nine of the kangaroo rats harvested Veldt grass seed. Though females collected more seed than males, there was no difference between the amounts (% of available seed) of Veldt grass and native seed collected. Habitat of origin (i.e., habitats with Veldt grass present or habitats without Veldt grass) had no effect on the amount of seed collected or the type of seed collected. During seed station trials, kangaroo rats were also recorded removing seed heads from naturally occurring Veldt grass stalks, providing clear documentation that Heermann’s kangaroo rats do collect Veldt grass seed. Accompanying laboratory seed preference trials were also conducted to confirm the consumption of Veldt grass seed. These controlled laboratory trials revealed that Heermann’s kangaroo rats will consume Veldt grass seed, although Veldt grass seed was consumed in smaller amounts (g) than millet and sunflower seed, which were presented simultaneously. These findings indicate that non-native Veldt grass may provide an additional or alternative source of seed for kangaroo rats, which could provide a partial explanation for why kangaroo rats are able to survive in monocultures of Veldt grass.

Changes in Lone Peak Conservation Nursery customer profiles cause state nursery leaders to question what their products are being used for and how trends in native plant use are changing the market for Utah native plants. The Utah native plant market is changing as interest in native plants is expanding to meet new conservation objectives, oftentimes in urban settings. This newer demand for native plants appears to be motivated by current changes in urban conservation behavior, continued population growth in the arid West, scarcity of water resources, the increasing appreciation for indigenous plant aesthetics, and concern for bio-diversity. A survey of2001 American Society of Landscape Architecture (ASLA) Utah Chapter members sponsored by Lone Peak Conservation Nursery, a state-mandated nursery for the supply of conservation plants to Utah, conveys landscape professionals' philosophical base for native plant choice, experience of native plant use, information needs, desired products and services, and general perception of native plant market and demand in Utah. Landscape architects at the forefront of these trends and the profession have the opportunity to be even more actively engaged in integrating native plant use across the wild land to urban landscape spectrum while collaborating with other industry leaders. Authors report on the significant findings from the Lone Peak ConservationNursery Native Plant Study to explain the complexity of native plant supply and demand in changing Utah markets. Increase in urban water conservation and aesthetic use of native plants and seeming instability in traditional restoration markets force local growers to face challenging decisions about plant production and business strategies. Business-driven decisions of suppliers may affect the availability of source-identified native plant products, and raises the question, "How native is native?" Current dilemmas in the Utah native plant market are identified as market pressures tend to generalize an ecologically specialized natural resource product. Continued research and industry collaboration is needed to better connect supply and demand to better balance the needs of private and public sector market actors sharing native plant resources.

Non-native plants have invaded over 100 millions of acres of western arid land in the US and dramatically altered nutrient cycling rates. Changes in water cycling caused by invasive species are of particular interest because primary production in the Western US is typically limited by water availability and aquifer recharge reflects plant demand. Large-scale invasions can, therefore, be expected to cause large-scale changes in hydrological cycles, but until recently, there have been considerable limitations in the ability to measure the timing, location, and extent of water use. Here we injected a tracer, deuterated water (D2O), into five soil depths in two sampling periods (May and June) in two adjacent plant communities (native and non-native dominated). Plants were sampled at several distances from the tracer addition area to determine the horizontal and vertical extent of water use in native and non-native communities. The tracer injection was coupled with measurements of leaf level stomatal conductance, leaf area index, and volumetric soil water content to estimate plant transpiration. We found that both native and non-native plants transpired water from primarily the top 60 cm of the soil (>75%), with a particular emphasis (≥ 50%) on shallow soil water (<10 cm) while lateral roots did not exceed 50 cm for most species. Higher leaf area index resulted in significantly more water being transpired from the native community. Some sharp distinctions in timing and location of tracer uptake resulting from the differing phenologies of the dominant species in each community were observed and confirmed previous mechanisms thought to govern plant assemblages in these communities. In May, the non-native community dominated by annual grasses had higher tracer uptake at 10 cm than the native community but began using deep water (higher tracer uptake at 80 cm) as annual grasses senesced and tap-rooted fobs became dominant in June. The perennial native species, however, used the entire soil profile from the moment they became active until they senesced. Our approach shows promise for overcoming the lack of resolution associated with natural abundance isotopes and other enrichment approaches, and for providing detailed measurements of plant water-use space.

Parrotfeather [Myriophyllum aquaticum (Vellozo) Verdecourt] is a non-native aquatic plant from South America that was introduced into the United States in the 1890's. Research was conducted to elucidate seasonal life history, starch allocation patterns, and key environmental factors that may affect plant growth. Environmental factors identified in field studies were used to develop a conceptual model to display relationships between growth and environmental factors. The conceptual model served as a broad-based hypothesis to parameterize growth limiting factors as it related to M. aquaticum growth. Mesocosm experiments were then conducted to test relationships depicted in the model and define the growth requirements of this species. Emergent shoot biomass, submersed shoot biomass, and sediment root biomass were related to light transmittance. Submersed shoot biomass was also related to water temperature. Stolons accounted for 40-95% of total biomass. Starch allocation was also greatest in stolons (78.1 g m-2); where up to 16.3% of total starch was stored. Low points in biomass and starch occurred from October to March. Biomass was greater when plants were grown in 30% shade, whereas plant length was greatest when plants were grown in 50% shade, with reductions observed in full sunlight. Biomass increased by 53% when nitrogen and phosphorus were added to the water column at 1.80 and 0.01 mg L-1, respectively. Myriophyllum aquaticum yield response was positively related (r2 = 0.82) to increasing nitrogen content and a critical concentration of 1.80% nitrogen and 0.20% phosphorus was identified for M. aquaticum growth. Plants grown at 0 cm water depth had 96% greater biomass than plants grown at water depths of 137 cm. Total length was 25% greater when plants were grown at water levels from 0-77 cm. Winter drawdowns reduced biomass by 99% at 4 weeks when compared to pre drawdown biomass. Summer drawdown efficacy was more rapid where biomass was reduced by 98% at 2 weeks when compared to pre drawdown biomass. Subsurface herbicide applications were not more efficacious than herbicides applied to the foliage. The foliar application of 2,4-D was the only herbicide and application method that resulted in ¡Ý90% biomass reduction of M. aquaticum.

No description available.