Post on 12-Jul-2015
Cushion plant effects on seed germination in an alpine environment
Amanda Liczner MSc. candidate
Presentation topics
Introduction
What is facilitation
Purpose, hypothesis
Methods
Field collection
Germination trials
Results
Implications
Introduction: facilitation is positive interactions between species
Bruno et al. 2003, Brooker et al. 2008
A B
A B
Introduction: nurse effects on beneficiary species
Temperature
Soil moisture
Soil nutrients
Wind
UV radiation
Cavieres et al. 2008; le Roux and McGeoch 2010; Anthelme et al 2012; Molenda et al 2012; Schoeb et al 2012
Purpose: to determine the influence of cushions on germination
Question: do seeds from open plants have greater germination in cushions?
Hypothesis: seeds from species in the open will benefit from decreased abiotic stress and thus will have greater germination within the cushion
Predictions:1. Plant height will be greater in the cushion2. Seed germination will be greater in the cushion3. Seeds will germinate faster in the open
Methods: surveyed cushion-open paired sites
Plant density of beneficiaries in cushion and openMeasured average plant height of beneficiaries
Methods: seeds were collected for germination trials
Seeds (10/species)
cushion chambers
open chambers
Methods: germination trials were conducted for 14d
Methods: germination trials were conducted for 14d
Results: plant density is greater in the open
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Results: plant height is greater in the open
Results: there is no difference in germination between microsites
Results: no difference between microsites for days to 50% germination
Implications: competition may prevent establishment on cushions
Although density is higher in the open there is no difference in germination between microsites
Implications: competition may prevent establishment on cushions
Environmental stress
Michalet et al. 2006; Brooker et al. 2008; He et al 2013; McIntire et al. 2013
Stre
ngt
h o
f fa
cilit
atio
n
Conclusions
Seeds from plants found primarily in the open germinate equally well in both microsites
These plants may be competitively excluded at another life stage
Thank you!
Ron Long
Christopher Lortie
Rick Bello
R2= 0.224
R2= 0.021
Purpose: some previous studies had conflicting results
shrub open