Format

Send to

Choose Destination
See comment in PubMed Commons below
Ann Bot. 2014 Jul;114(1):85-96. doi: 10.1093/aob/mcu082. Epub 2014 May 20.

Two decades of demography reveals that seed and seedling transitions limit population persistence in a translocated shrub.

Author information

  • 1Ecosystem Management, University of New England, Armidale, NSW 2351, Australia cgross@une.edu.au.
  • 2Ecosystem Management, University of New England, Armidale, NSW 2351, Australia.

Abstract

BACKGROUND AND AIMS:

Olearia flocktoniae is an endangered shrub that was passively translocated from its natural ecosystem, where it has since gone extinct. This study aimed to determine sensitivities vital to populations persisting in human-created areas.

METHODS:

Population colonization, longevity and extinction were investigated over 20 years using 133 populations. Seed-bank longevity was determined from germination trials of seeds exhumed from extinct and extant sites via a 10-year glasshouse trial and by in situ sowing experiments. From 27 populations, 98 cohorts were followed and matrix models of transitions from seeds to adults were used to evaluate the intrinsic rate of population growth against disturbance histories. Ten populations (38 cohorts) with different disturbance histories were used to evaluate sensitivities in vital rates.

KEY RESULTS:

Most populations had few individuals (∼30) and were transient (<5 years above ground). The intrinsic population growth rate was rarely >1 and all but two populations were extinct at year 20. Seeds were short-lived in situ. Although >1000 seeds per plant were produced annually in most populations, sensitivity analysis showed that the transition to the seed bank and the transition from the seed bank to seedlings are key vulnerabilities in the life-cycle.

CONCLUSIONS:

Seedling establishment is promoted by recent disturbance. Increasing the number of disturbance events in populations, even severe disturbances that almost extirpate populations, significantly increases longer-term population persistence. Only populations that were disturbed annually survived the full 20 years of the study. The results show that translocated populations of O. flocktoniae will fail to persist without active management.

KEYWORDS:

Asteraceae; Dorrigo daisy bush; Olearia flocktoniae; displaced species; elasticity analysis; endangered species; extinction patterns; habitat shift; life-history analysis; local extinction; pioneer species; seed bank recovery; sensitivity analyses; survivorship

PMID:
24844983
PMCID:
PMC4071100
DOI:
10.1093/aob/mcu082
[PubMed - indexed for MEDLINE]
Free PMC Article
PubMed Commons home

PubMed Commons

0 comments
How to join PubMed Commons

    Supplemental Content

    Full text links

    Icon for HighWire Icon for PubMed Central
    Loading ...
    Support Center