Fine-scale spatial heterogeneity and seed size determine early seedling survival in a desert perennial shrub (<Emphasis Type="Italic">Ericameria nauseosa:</Emphasis> Asteraceae) |
| |
Authors: | Rebecca Balogh Benard Catherine A Toft |
| |
Institution: | (1) Section of Evolution and Ecology, University of California, Davis, 95616, USA |
| |
Abstract: | In heterogenous landscapes, seeds settle in some microsites more readily than others, independently of whether those microsites
are suitable for germination and subsequent growth, and survival of seedlings. Wild seeds and seedlings of Ericameria
nauseosa var. oreophila in the sand-dune ecosystem near Mono Lake, California show both concordance and conflict in where seeds are retained and
where seedlings flourish. Using a field experiment, we followed performance of seeds and seedlings (i.e., the rate of germination
and successful emergence, initial seedling size, seedling growth and survival over first growing season), by planting seeds
of known sizes in pre-identified microsites (windward and lee aspects of interspaces between shrubs, under shrub canopies,
and under snag canopies, respectively). Heavier seeds were more likely to germinate and emerge successfully and resulted in
initially larger seedlings than lighter seeds. These initially larger seedlings subsequently remained larger over the growing
season and lived longer than initially smaller seedlings. Independent of seed and initial seedling size, seedlings that germinated
under the canopy of adult shrubs grew larger and survived longer than seedlings that germinated in interspaces (open space
with little or no vegetation) or under snags (dead adult shrubs). Seedlings grown under the canopy of adult shrubs experienced
significantly less solar radiation and wind-deposited sand than seedlings grown in interspace or snag microsites. Sand burial
more than 1 cm was lethal for seedlings. The two variables of seed size and microsite type had by far greater impact on eventual
growth and survival of seedlings than did aspect, and the effects of the former two variables were independent of each other.
This study amplifies the body of work on E. nauseosa at this site demonstrating that the earliest events in the life history of this long-lived perennial shrub appear to persist
through time despite the harsh and variable environment. |
| |
Keywords: | Seedling establishment Seed size variation Microsite Desert perennial shrub Nurse plant |
本文献已被 SpringerLink 等数据库收录! |
|