|Denny, M - N. CHEYENNE EXTENSION|
|Jacobs, J - MONTANA STATE UNIV|
|Pokorny, M - MONTANA STATE UNIV|
Submitted to: Society for Ecological Restoration Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: September 1, 2003
Publication Date: N/A
Interpretive Summary: It may be possible to enhance culturally and ecologically important forbs during restoration by creating small, carefully cultivated 'seed source islands' from which plants disperse themselves naturally over time. In our tests, all three forbs used increased in occurrence across the landscape three years after establishing islands. However, the shape (square versus rectangular) of the island did not affect forb distribution. We believe establishing seed islands of forbs or other desired species during restoration, especially after application of a broadleaf herbicide during weed control may enhance species richness and diversity and provide species critical for invasion resistance.
Technical Abstract: Landscape scale establishment of desirable indigenous forbs may be essential for restoring plant community function and structure, and reducing invasibility. Objectives of this study were to quantify the establishment and dispersal of forb species using seed source islands. Treatments (3 seeded species x 2 island shapes) were established in a randomized-complete-block design with 3 replications at two reclaimed coal mine sites in 1998. Seed source islands were tilled in a 1x9-m rectangle or a 3x3-m square. One of three indigenous forb species were broadcasted onto each island: Echinacea angustifolia at 2,133 seeds/m2, Artemisia ludoviciana at 161 seeds/m2, or Pendiomelum esculentum at 161 seeds/m2. Density was counted in 1999, 2000, and 2002. In 2002, the entire landscape was sampled using GPS unites to map new forb populations. An ArcView spatial analyst script was used to compute distance between forb occurrences and their nearest seed source island. ANOVA indicated seedling density depended upon site, species, and year after seeding. By 2002, the percent of seed to germinate and establish averaged 4% for A. Ludoviciana, 1% for E. Angustifolia, and <1% for P. Esculentum. Dispersal of seeded species depended on species and island shape. By 2002, forbs dispersed to an average 4 (A. ludoviciana), 73 (E. angustifolia), and zero (P. esculentum) new occurrences that were more commonly associated with rectangular islands. We speculated that site variability or secondary dispersal was associated with establishment of new populations. Seed source islands may have potential to provide a low input method of increasing species diversity and frequency across restored landscapes by combining time, dense seeding rates, and natural dispersal mechanisms.