Physical Sciences and Mathematics Commons^™

Local Adaptation Constrains Drought Tolerance In A Tropical Foundation Tree, Kasey E. Barton, Casey Jones, Kyle F. Edwards, Aaron B. Shiels, Tiffany Knight

USDA Wildlife Services: Staff Publications

1. Plant species with broad climatic ranges might be more vulnerable to climate change than previously appreciated due to intraspecific variation in climatic stress tolerance. In tropical forests, drought is increasingly frequent and severe, causing widespread declines and altering community dynamics. Yet, little is known about whether foundation tropical trees vary in drought tolerance throughout their distributions, and how intraspecific variation in drought tolerance might contribute to their vulnerability to climate changE.
2. We tested for local adaptation in seedling emergence and establishment with a full-factorial reciprocal transplant experiment including 27 populations and 109,350 seeds along a 3,500 mm precipitation gradient for …

Inter- And Intra-Specific Interactions In Germination And Seedling Establishment Of Cheatgrass And Russian Wildrye, Erin K. Espeland

The Prairie Naturalist

Cheatgrass (Bromus tectorum) is an invasive species in the arid and semi-arid west of the USA, and is weedy in disturbed prairie landscapes. Perennial Russian wildrye (Psathyrostachys juncea) limits population growth of cheatgrass, but the mechanism is unclear. I conducted glasshouse and greenhouse experiments to test if intra- and interspecific competitive interactions of seeds and seedlings of cheatgrass and Russian wildrye were different across a geographic soil gradient with different cultivation legacies in eastern Montana, USA. Seed-seed interactions occurred in both species. Cheatgrass and Russian wildrye inhibited one another’s emergence in one edaphic condition in one experiment. Cheatgrass growth was …

Scarification And Gap Size Have Interacting Effects On Northern Temperate Seedling Establishment, John L. Willis, Michael B. Walters, Kurt W. Gottschallk

USDA Forest Service / UNL Faculty Publications

After decades focused on promoting economically valuable species, management of northern temperate forests has increasingly become focused on promoting tree species diversity. Unfortunately, many formerly common species that could contribute to diversity including yellow birch (Betula alleghaniensis Britton.), paper birch (Betula papyrifera Marsh), eastern hemlock (Tsuga canadensis L.), and eastern white pine (Pinus strobus L.) are now uncommon in the seedling layer, raising concerns about our ability to use these species to increase diversity. In this study, two related seed addition experiments conducted in 45 variably-sized harvest gaps (unharvested to 6500 m^2) in adjacent mesic northern hardwood stands, Emmet County, …

Germination Response Of Prairie Dropseed And Hairy Goldaster To Stratification And Temperature, Aurora R. Roemmich, Jack L. Bulter, Gary E. Larson, E. Brent Turnipseed

The Prairie Naturalist

The unique vegetation assemblage of the Black Hills in conjunction with the frequent occurrence of natural and anthropogenic disturbances emphasizes the need to use locally adapted native species in a wide variety of restoration efforts. However, a general lack of information regarding germination and propagation requirements for most native plant species has restricted their usage. A better understanding of dormancy and germination patterns for native species will increase their availability and affordability. We selected two common native species, hairy goldaster (Heterotheca villosa) and prairie dropseed (Sporobolus heterolepis), to determine their optimum germination conditions. We hand-harvested seeds during 2007–2009 for use …

In Situ Development Of Western Prairie Fringed Orchid Seeds, Protocorms, And Seedlings In Grazed And Non-Grazed Prairie Habitat, Bonnie Warner Alexander, Donald Kirby, Mario Biondini, Edward Dekeyser

The Prairie Naturalist

In 1989, the U.S. Fish and Wildlife Service listed the western prairie fringed orchid (Platanthera praeclara) as threatened. Although this orchid has been monitored for years, there is little scientific documentation of its biology, ecology, and phenology, nor the impacts of management activities on its populations. Our objectives were to document seed germination and seedling production rates after one year in situ, and compare seed germination in grazed and non-grazed prairie habitat in the Sheyenne National Grassland (SNG) in southeastern North Dakota. Of 18,717 planted seeds, we recovered 1,561 swollen embryos, 94 protocorms, and 51 seedlings. We documented no difference …

Influence Of Biocontrol Insects On Canada Thistle: Seed Production, Germinability, And Viability, Gary E. Larson, Tim A. Wittig, Kenneth F. Higgins, Brent Turnipseed, Dawn M. Gardner

The Prairie Naturalist

We conducted surveys of thistle-feeding insects on Canada thistle [Cirsium arvense (L.) Scop.] during the 2000 and 2001 growing seasons at Lacreek National Wildlife Refuge (LNWR), South Dakota, and analyzed their impact on thistle seed production, germination, and viability. Insects included Canada thistle stem weevil [Hadroplontus litura, formerly Ceurtorhynchus lilura, (Coleoptera: Curculionidae)], introduced at LNWR as a biocontrol agent, plus two seed head parasites, the thistle head weevil [Rhinocyllus conicus (Coleoptera: Curculionidae)] and the seed head fly [Terellia ruficauda (Diptera: Tephritidae)]. Infestation by these insects caused no significant reduction in per-head seed yield, with means ranging from 82.5 seeds per …

Reproductive Ecology Of Two Common Woody Species, Juniperus Sabina And Artemisia Santolinifolia, In Mountain Steppes Of Southern Mongolia, Katrin Ronnenberg

Erforschung biologischer Ressourcen der Mongolei / Exploration into the Biological Resources of Mongolia, ISSN 0440-1298

The present study describes the reproductive ecology of the prostrate shrub Juniperus sabina and the dwarf shrub Artemisia santolinifolia in dry mountain steppes of southern Mongolia. Whereas stands of the juniper are located at the drought limit of the genus’ distributional range, the genus Artemisia is typical of central Asian drylands. Both species produce large numbers of reproductive organs. For Juniperus sabina, however, only 2.5% of the morphologically intact seeds were found to be viable. Correspondingly, neither seedlings nor saplings were found in the field, and recruitment by reseeding happens at most rarely under the present climatic conditions.

Instead, …