---
_id: '315'
abstract:
- lang: eng
  text: 'More than 100 years after Grigg’s influential analysis of species’ borders,
    the causes of limits to species’ ranges still represent a puzzle that has never
    been understood with clarity. The topic has become especially important recently
    as many scientists have become interested in the potential for species’ ranges
    to shift in response to climate change—and yet nearly all of those studies fail
    to recognise or incorporate evolutionary genetics in a way that relates to theoretical
    developments. I show that range margins can be understood based on just two measurable
    parameters: (i) the fitness cost of dispersal—a measure of environmental heterogeneity—and
    (ii) the strength of genetic drift, which reduces genetic diversity. Together,
    these two parameters define an ‘expansion threshold’: adaptation fails when genetic
    drift reduces genetic diversity below that required for adaptation to a heterogeneous
    environment. When the key parameters drop below this expansion threshold locally,
    a sharp range margin forms. When they drop below this threshold throughout the
    species’ range, adaptation collapses everywhere, resulting in either extinction
    or formation of a fragmented metapopulation. Because the effects of dispersal
    differ fundamentally with dimension, the second parameter—the strength of genetic
    drift—is qualitatively different compared to a linear habitat. In two-dimensional
    habitats, genetic drift becomes effectively independent of selection. It decreases
    with ‘neighbourhood size’—the number of individuals accessible by dispersal within
    one generation. Moreover, in contrast to earlier predictions, which neglected
    evolution of genetic variance and/or stochasticity in two dimensions, dispersal
    into small marginal populations aids adaptation. This is because the reduction
    of both genetic and demographic stochasticity has a stronger effect than the cost
    of dispersal through increased maladaptation. The expansion threshold thus provides
    a novel, theoretically justified, and testable prediction for formation of the
    range margin and collapse of the species’ range.'
article_number: e2005372
article_processing_charge: No
author:
- first_name: Jitka
  full_name: Polechova, Jitka
  id: 3BBFB084-F248-11E8-B48F-1D18A9856A87
  last_name: Polechova
  orcid: 0000-0003-0951-3112
citation:
  ama: Polechova J. Is the sky the limit? On the expansion threshold of a species’
    range. <i>PLoS Biology</i>. 2018;16(6). doi:<a href="https://doi.org/10.1371/journal.pbio.2005372">10.1371/journal.pbio.2005372</a>
  apa: Polechova, J. (2018). Is the sky the limit? On the expansion threshold of a
    species’ range. <i>PLoS Biology</i>. Public Library of Science. <a href="https://doi.org/10.1371/journal.pbio.2005372">https://doi.org/10.1371/journal.pbio.2005372</a>
  chicago: Polechova, Jitka. “Is the Sky the Limit? On the Expansion Threshold of
    a Species’ Range.” <i>PLoS Biology</i>. Public Library of Science, 2018. <a href="https://doi.org/10.1371/journal.pbio.2005372">https://doi.org/10.1371/journal.pbio.2005372</a>.
  ieee: J. Polechova, “Is the sky the limit? On the expansion threshold of a species’
    range,” <i>PLoS Biology</i>, vol. 16, no. 6. Public Library of Science, 2018.
  ista: Polechova J. 2018. Is the sky the limit? On the expansion threshold of a species’
    range. PLoS Biology. 16(6), e2005372.
  mla: Polechova, Jitka. “Is the Sky the Limit? On the Expansion Threshold of a Species’
    Range.” <i>PLoS Biology</i>, vol. 16, no. 6, e2005372, Public Library of Science,
    2018, doi:<a href="https://doi.org/10.1371/journal.pbio.2005372">10.1371/journal.pbio.2005372</a>.
  short: J. Polechova, PLoS Biology 16 (2018).
date_created: 2018-12-11T11:45:46Z
date_published: 2018-06-15T00:00:00Z
date_updated: 2025-07-10T11:52:27Z
day: '15'
ddc:
- '576'
department:
- _id: NiBa
doi: 10.1371/journal.pbio.2005372
file:
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  creator: dernst
  date_created: 2019-01-22T08:30:03Z
  date_updated: 2020-07-14T12:46:01Z
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file_date_updated: 2020-07-14T12:46:01Z
fulldoi: https://doi.org/10.1371/journal.pbio.2005372
has_accepted_license: '1'
intvolume: '        16'
issue: '6'
language:
- iso: eng
month: '06'
oa: 1
oa_version: Published Version
publication: PLoS Biology
publication_identifier:
  issn:
  - 1544-9173
publication_status: published
publisher: Public Library of Science
publist_id: '7550'
quality_controlled: '1'
related_material:
  record:
  - id: '9839'
    relation: research_data
    status: public
scopus_import: '1'
status: public
title: Is the sky the limit? On the expansion threshold of a species’ range
tmp:
  image: /images/cc_by.png
  legal_code_url: https://creativecommons.org/licenses/by/4.0/legalcode
  name: Creative Commons Attribution 4.0 International Public License (CC-BY 4.0)
  short: CC BY (4.0)
type: journal_article
user_id: 2DF688A6-F248-11E8-B48F-1D18A9856A87
volume: 16
year: '2018'
...