The Role of Native Annual Forbs in the
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The Role of Native Annual Forbs in the Restoration of Invaded Rangelands Erin Goergen, Elizabeth Leger, Tara Forbis University of Nevada, Reno USDA ARS Reno, NV Restoration of degraded communities is costly and difficult. Restoration of degraded communities is costly and difficult. • Weather • Seeding method • Seeds • Species mixes Natural Succession Disturbance Annuals Early seral perennials Late seral perennials & shrubs • • • • • • Seed Mix 1 Artemisia tridentata Elymus lanceolatus Leymus cinereus Poa secunda Pseudoroegneria spicata Achillea millefolium • • • • • Seed Mix 2 Artemisia tridentata Achnatherum hymenoides Elymus lanceolatus Poa secunda Pseudoroegneria spicata Seed Mix 3 • • • • • • • • • • • Artemisia tridentata Purshia tridentata Achnatherum hymenoides Agropyron crestatum Elymus lanceolatus Leymus cinereus Pascopyrum smithii Poa secunda Pseudoroegneria spicata Achillea millefolium Medicago sativa Can we improve restoration success by more closely following natural successional patterns? Disturbance Annuals Early seral perennials Late seral perennials & shrubs Native annual forbs may be valuable restoration species for multiple reasons 1. Adapted to post-disturbance environmental conditions. 2. Likely to be phenologically similar to and competitive with Bromus tectorum. 3. Contribute to plant diversity and habitat in rangelands. Native annuals can be abundant! Annuals increase after disturbance! • Native annual forbs have relatively low abundance in climax sagebrush communities. • Underdown Canyon, Austin NV – 1 year after fire, native annual forbs increased by 70% – Cover stayed high even 3 years post-fire Annuals are good competitors! Cryptantha pterocarya 25 – 85% reduced! Collinsia parviflora 25 – 35% reduced! There is overlap in phenology Fall Winter Spring Bromus tectorum Annual forbs Forbis (2010) Plant Species Biology 25:221-230 Summer Fall _ B. tectorum Native perennial grasses Native annual forbs _ _ _ B. tectorum Native perennial grasses Native annual forbs _ + _ _ B. tectorum Native perennial grasses Can seeding native annual forbs improve establishment of the short-lived, native perennial grass Elymus multisetus? Questions 1. What is the effect of individual annuals, on Elymus multisetus and Bromus tectorum? 2.When grown in mixtures, what effect do annual forbs have on Elymus multisetus and Bromus tectorum? Field Experiment • Target E. multisetus and B. tectorum – grown alone, with single annual forb species, B. tectorum, or forb + B. tectorum. • 5 Native forbs chosen: Amsinckia tesellata AMTE Amsinckia intermedia AMIN Mentzelia veatchiana MEVE Descurinia pinnata DEPI Blepharipappus scaber BLSC Experimental Design Target: Elymus multisetus or Bromus tectorum Competitors: none, annual forb, B. tectorum, or both Seeds were sown around a target plant at typical field densities Questions 1.What is the effect of individual annuals, on target Elymus multisetus and Bromus tectorum? 1. ELMU grows best with BLSC, DEPI, and MEVE E. multesitus aboveground biomass (g) A AB 1 70% 75% 83% 0.5 B 94% 99% 97% 0 AMTE AMIN BRTE MEVE DEPI BLSC 1. Competitive pressure on BRTE is not equal! B. tectorum vegetative biomass (g) 3.5 A AB 3 38% 2.5 46% 2 59% 1.5 BC 1 C 0.5 84% 88% 97% 0 AMTE BRTE AMIN MEVE DEPI BLSC Questions 2. When grown in mixtures, what effect do annual forbs have on Elymus multisetus and Bromus tectorum? MEVE and BRTE AM and BRTE 2. When with BRTE, ELMU is larger when MEVE is also present. E. multesitus aboveground biomass (g) 0.5 71% 0.4 0.3 27% 0.2 BRTE 60% 0.1 79% 95% 0 BRTE+AMTE BRTE+AMIN BRTE+DEPI BRTE+BLSC BRTE+MEVE 2. BRTE is most impacted when grown with AMTE and AMIN. A B. tectorum vegetative biomass (g) 1 90% AB 0.5 6% 7% BC 51% C 88% 0 BRTE+AMTE BRTE+AMIN BRTE+DEPI BRTE+MEVE BRTE+BLSC Field summary • A. tesselata and A. intermedia show promise as a good competitors against B. tectorum. • M. veatchiana has the potential to facilitate establishment of E. multisetus. Next steps • Multiple years! • We need to learn more about our native annual forbs! – Germination strategies – Dormancy issues – Competitive abilities Questions?
