title: Evolutionary drivers of mast-seeding in a long-lived desert shrub.
abstract: OBJECTIVE
  The evolutionary drivers and proximal regulators of mast-seeding are well understood for species of mesic environments, but how these regulators interact with high spatial and interannual variability in growing-season precipitation for a masting species in a desert environment has never been examined.
  
  
  METHODS
  We followed flowering and seed production in 16 populations of the North American desert shrub blackbrush (Coleogyne ramosissima) from contrasting environments across its range over an 11-year period to determine patterns of interannual reproductive output variation.
  
  
  RESULTS
  Patterns of reproductive output in blackbrush did not track current growing season precipitation, but instead were regulated by prior-year weather cues. The strength of the response to the masting cue depended on habitat quality, with higher mean reproductive output, shorter intervals between years of high seed production, and lower CVp at more favorable sites. Wind pollination efficiency was demonstrated to be an important evolutionary driver of masting in blackbrush, and satiation of heteromyid seed predator-dispersers was supported as an evolutionary driver based on earlier studies.
  
  
  CONCLUSIONS
  Both the evolutionary drivers and proximal regulators of masting in blackbrush are similar to those demonstrated for masting species of mesic environments. Relatively low synchrony across populations in response to regional masting cues occurs at least partly because prior-year environmental cues can trigger masting efforts in years with resource limitation due to suboptimal precipitation, especially in more xeric low-elevation habitats.
authors.affiliation: US Forest Service, Rocky Mountain Research Station, Shrub Sciences Laboratory, 735 N 500 E, Provo, Utah 84606 semeyer@xmission.com smeyer@fs.fed.us.
authors.forename: Susan E
authors.initials: SE
authors.lastname: Meyer
authors.affiliation: US Forest Service, Rocky Mountain Research Station, 333 Broadway SE, Albuquerque, New Mexico 87102.
authors.forename: Burton K
authors.initials: BK
authors.lastname: Pendleton
mesh_terms: D005075:Biological Evolution; D017753:Ecosystem; D035264:Flowers / Q000254:growth & development; D009505:Nevada; D027824:Rosaceae / Q000254:growth & development / Q000502:physiology*; D012621:Seasons; D012639:Seeds / Q000254:growth & development*; D014589:Utah
keywords: Coleogyne ramosissima; blackbrush; mass flowering; predator satiation; resource matching; wind pollination efficiency