Reproductive biologies and pollinators of common Great Basin restoration forbs, and consequences of fire for bee and forb reproduction


Jim Cane, USDA-ARS Pollinating Insect Research Unit, Utah State University, Logan, UT 435-797-3879

Study Dates:

May 2007-2008

SageSTEP Study Plots:

Onaqui p-j and sagebrush sites, others in the network with controlled burns and adequate stands of select floral hosts in and out of fire (see appended list of selected plant species above)

Study Design and Objectives:

Native bees and/or honey bees are needed to pollinate most of the wildflower species considered for Great Basin rehabilitation. Most of these species are requiring pollinators for seed set, mostly by native bees. The pollinator faunas of many candidate plant genera include one or more bee genera with potentially manageable species with promise for seed farming and production. The researcher is surveying native bee faunas at wild flowering populations to evaluate them for manageable bee species. One of the candidate flower genera for seed production is globemallows (Sphaeralcea). Based on data collected from a 2006 experimentation, researchers determined that these species require a pollinator for successful reproduction.

To be identified, bees must be collected. Sampling protocol for this study represents the density of each bee species at flowers on a per plant basis. Typically, researchers collect enough to obtain 30 individual bees or the bees from 200 plants, whichever comes first, as it is among the common visitors that the important pollinators will exist. Collection of 1-2 such pollinator samples from 1-2 burned and control plots where blooming globemallow are found will be used to identify bees that are important pollinators of these species and whether the pollinators are potential candidates for management. Researchers hope to develop sustainably managed pollinators that can be used on farms which will grow native Sphaeralcea spp. for BLM restoration purposes.

In addition, researchers have begun a data set that will allow them to evaluate the effects of fire on these pollinator guilds, in cases where good fire records are available. Researchers expect the season of fire occurrence (during or after bloom?) and bees’ nesting habits (above-ground or underground) to profoundly influence their population response to fire, and therefore, their availability to pollinate flowers in following years for the next generation of forbs at restoration sites. For these studies, bee samples at the target forb(s) are augmented by passive pan-trap samples to represent the bee community from which the guild is drawn (and active on that date). Salient forb and sagebrush density data are also characterized at the time of sampling. Target forb species for the Intermountain West are listed below.

Family Species
Apiaceae Lomatium dissectum (Nutt.) Math. & Const.
  L. triternatum (Pursh) Coult. & Rose
Asteraceae Balsamorhiza sagittata (Pursh) Nutt.
  Crepis acuminata Nutt.
Cleomaceae Cleome lutea Hook
  C. serrulata Pursh
Fabaceae Astragalus filipes Torr.
  Dalea ornatum (Dougl.) Barneby
  D. searlsiae (Gray) Barneby
  Hedysarum boreale Nutt.
  Lupinus argenteus Pursh
  L. sericeus Pursh
Malvaceae Sphaeralcea grossularifolia (H. & A.) Rydb.
  S. munroana (Dougl.) Spach.
Plantaginaceae Penstemon speciosus Dougl.
Polygonaceae Eriogonum umbellatum Torr.

Additional Information: