Impacts of climate variability and human colonization on the vegetation of the Galápagos Islands

Alejandra Restrepo, Paul Colinvaux, Mark Bush, Alexander Correa-Metrio, Jessica Conroy, Mark R. Gardener, Patricia Jaramillo, Miriam Steinitz-Kannan, Jonathan Overpeck

Research output: Contribution to journalArticle

30 Citations (Scopus)

Abstract

A high-resolution (2-9 year sampling interval) fossil pollen record from the Galapagos Islands, which spans the last 2690 years, reveals considerable ecosystem stability. Vegetation changes associated with independently derived histories of El Niño Southern Oscillation variability provided evidence of shifts in the relative abundance of individual species rather than immigration or extinction. Droughts associated with the Medieval Climate Anomaly induced rapid ecological change that was followed by a reversion to the previous state. The paleoecological data suggested nonneutral responses to climatic forcing in this ecosystem prior to the period of human influence. Human impacts on the islands are evident in the record. A marked decline in long-term codominants of the pollen record, Alternanthera and Acalypha, produced a flora without modern analogue before 1930. Intensified animal husbandry after ca. 1930 may have induced the local extinction of Acalypha and Alternanthera. Reductions in populations of grazing animals in the 1970s and 1980s did not result in the return of the native flora, but in invasions by exotic species. After ca. 1970 the trajectory of habitat change accelerated, continuously moving the ecosystem away from the observed range of variability in the previous 2690 years toward a novel ecosystem. The last 40 years of the record also suggest unprecedented transport of lowland pollen to the uplands, consistent with intensified convection and warmer wet seasons.

Original languageEnglish (US)
Pages (from-to)1853-1866
Number of pages14
JournalEcology
Volume93
Issue number8
DOIs
StatePublished - Aug 2012

Fingerprint

colonization
Acalypha
Alternanthera
climate
vegetation
pollen
ecosystems
ecosystem
flora
extinction
Galapagos Islands
animal husbandry
local extinction
Southern Oscillation
warm season
Medieval
anthropogenic effect
immigration
wet season
trajectories

Keywords

  • Climate change
  • Cloud
  • El Niño
  • Exotic invasive species
  • Extinction
  • Galápagos
  • Human impact
  • La niña
  • Paleoecology
  • Rate of ecological change
  • Stability

ASJC Scopus subject areas

  • Ecology, Evolution, Behavior and Systematics

Cite this

Restrepo, A., Colinvaux, P., Bush, M., Correa-Metrio, A., Conroy, J., Gardener, M. R., ... Overpeck, J. (2012). Impacts of climate variability and human colonization on the vegetation of the Galápagos Islands. Ecology, 93(8), 1853-1866. https://doi.org/10.1890/11-1545.1

Impacts of climate variability and human colonization on the vegetation of the Galápagos Islands. / Restrepo, Alejandra; Colinvaux, Paul; Bush, Mark; Correa-Metrio, Alexander; Conroy, Jessica; Gardener, Mark R.; Jaramillo, Patricia; Steinitz-Kannan, Miriam; Overpeck, Jonathan.

In: Ecology, Vol. 93, No. 8, 08.2012, p. 1853-1866.

Research output: Contribution to journalArticle

Restrepo, A, Colinvaux, P, Bush, M, Correa-Metrio, A, Conroy, J, Gardener, MR, Jaramillo, P, Steinitz-Kannan, M & Overpeck, J 2012, 'Impacts of climate variability and human colonization on the vegetation of the Galápagos Islands', Ecology, vol. 93, no. 8, pp. 1853-1866. https://doi.org/10.1890/11-1545.1
Restrepo A, Colinvaux P, Bush M, Correa-Metrio A, Conroy J, Gardener MR et al. Impacts of climate variability and human colonization on the vegetation of the Galápagos Islands. Ecology. 2012 Aug;93(8):1853-1866. https://doi.org/10.1890/11-1545.1
Restrepo, Alejandra ; Colinvaux, Paul ; Bush, Mark ; Correa-Metrio, Alexander ; Conroy, Jessica ; Gardener, Mark R. ; Jaramillo, Patricia ; Steinitz-Kannan, Miriam ; Overpeck, Jonathan. / Impacts of climate variability and human colonization on the vegetation of the Galápagos Islands. In: Ecology. 2012 ; Vol. 93, No. 8. pp. 1853-1866.
@article{223bd3456903448b98138efa1c3ddc52,
title = "Impacts of climate variability and human colonization on the vegetation of the Gal{\'a}pagos Islands",
abstract = "A high-resolution (2-9 year sampling interval) fossil pollen record from the Galapagos Islands, which spans the last 2690 years, reveals considerable ecosystem stability. Vegetation changes associated with independently derived histories of El Ni{\~n}o Southern Oscillation variability provided evidence of shifts in the relative abundance of individual species rather than immigration or extinction. Droughts associated with the Medieval Climate Anomaly induced rapid ecological change that was followed by a reversion to the previous state. The paleoecological data suggested nonneutral responses to climatic forcing in this ecosystem prior to the period of human influence. Human impacts on the islands are evident in the record. A marked decline in long-term codominants of the pollen record, Alternanthera and Acalypha, produced a flora without modern analogue before 1930. Intensified animal husbandry after ca. 1930 may have induced the local extinction of Acalypha and Alternanthera. Reductions in populations of grazing animals in the 1970s and 1980s did not result in the return of the native flora, but in invasions by exotic species. After ca. 1970 the trajectory of habitat change accelerated, continuously moving the ecosystem away from the observed range of variability in the previous 2690 years toward a novel ecosystem. The last 40 years of the record also suggest unprecedented transport of lowland pollen to the uplands, consistent with intensified convection and warmer wet seasons.",
keywords = "Climate change, Cloud, El Ni{\~n}o, Exotic invasive species, Extinction, Gal{\'a}pagos, Human impact, La ni{\~n}a, Paleoecology, Rate of ecological change, Stability",
author = "Alejandra Restrepo and Paul Colinvaux and Mark Bush and Alexander Correa-Metrio and Jessica Conroy and Gardener, {Mark R.} and Patricia Jaramillo and Miriam Steinitz-Kannan and Jonathan Overpeck",
year = "2012",
month = "8",
doi = "10.1890/11-1545.1",
language = "English (US)",
volume = "93",
pages = "1853--1866",
journal = "Ecology",
issn = "0012-9658",
publisher = "Ecological Society of America",
number = "8",

}

TY - JOUR

T1 - Impacts of climate variability and human colonization on the vegetation of the Galápagos Islands

AU - Restrepo, Alejandra

AU - Colinvaux, Paul

AU - Bush, Mark

AU - Correa-Metrio, Alexander

AU - Conroy, Jessica

AU - Gardener, Mark R.

AU - Jaramillo, Patricia

AU - Steinitz-Kannan, Miriam

AU - Overpeck, Jonathan

PY - 2012/8

Y1 - 2012/8

N2 - A high-resolution (2-9 year sampling interval) fossil pollen record from the Galapagos Islands, which spans the last 2690 years, reveals considerable ecosystem stability. Vegetation changes associated with independently derived histories of El Niño Southern Oscillation variability provided evidence of shifts in the relative abundance of individual species rather than immigration or extinction. Droughts associated with the Medieval Climate Anomaly induced rapid ecological change that was followed by a reversion to the previous state. The paleoecological data suggested nonneutral responses to climatic forcing in this ecosystem prior to the period of human influence. Human impacts on the islands are evident in the record. A marked decline in long-term codominants of the pollen record, Alternanthera and Acalypha, produced a flora without modern analogue before 1930. Intensified animal husbandry after ca. 1930 may have induced the local extinction of Acalypha and Alternanthera. Reductions in populations of grazing animals in the 1970s and 1980s did not result in the return of the native flora, but in invasions by exotic species. After ca. 1970 the trajectory of habitat change accelerated, continuously moving the ecosystem away from the observed range of variability in the previous 2690 years toward a novel ecosystem. The last 40 years of the record also suggest unprecedented transport of lowland pollen to the uplands, consistent with intensified convection and warmer wet seasons.

AB - A high-resolution (2-9 year sampling interval) fossil pollen record from the Galapagos Islands, which spans the last 2690 years, reveals considerable ecosystem stability. Vegetation changes associated with independently derived histories of El Niño Southern Oscillation variability provided evidence of shifts in the relative abundance of individual species rather than immigration or extinction. Droughts associated with the Medieval Climate Anomaly induced rapid ecological change that was followed by a reversion to the previous state. The paleoecological data suggested nonneutral responses to climatic forcing in this ecosystem prior to the period of human influence. Human impacts on the islands are evident in the record. A marked decline in long-term codominants of the pollen record, Alternanthera and Acalypha, produced a flora without modern analogue before 1930. Intensified animal husbandry after ca. 1930 may have induced the local extinction of Acalypha and Alternanthera. Reductions in populations of grazing animals in the 1970s and 1980s did not result in the return of the native flora, but in invasions by exotic species. After ca. 1970 the trajectory of habitat change accelerated, continuously moving the ecosystem away from the observed range of variability in the previous 2690 years toward a novel ecosystem. The last 40 years of the record also suggest unprecedented transport of lowland pollen to the uplands, consistent with intensified convection and warmer wet seasons.

KW - Climate change

KW - Cloud

KW - El Niño

KW - Exotic invasive species

KW - Extinction

KW - Galápagos

KW - Human impact

KW - La niña

KW - Paleoecology

KW - Rate of ecological change

KW - Stability

UR - http://www.scopus.com/inward/record.url?scp=84864706695&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=84864706695&partnerID=8YFLogxK

U2 - 10.1890/11-1545.1

DO - 10.1890/11-1545.1

M3 - Article

VL - 93

SP - 1853

EP - 1866

JO - Ecology

JF - Ecology

SN - 0012-9658

IS - 8

ER -