Impacts of herbivory by ecological replacements on an island ecosystem

Allbwn ymchwil: Cyfraniad at gyfnodolynErthygladolygiad gan gymheiriaid

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Dangosydd eitem ddigidol (DOI)

  • Rosemary Moorhouse-Gann
    School of Healthcare Sciences, Cardiff UniversityDurrell Wildlife Conservation Trust
  • Ian Vaughan
    School of Healthcare Sciences, Cardiff University
  • Nik Cole
    Durrell Wildlife Conservation TrustMauritian Wildlife Foundation
  • Martine Goder
    Mauritian Wildlife Foundation
  • Vikash Tatayah
    Mauritian Wildlife Foundation
  • Carl Jones
    Durrell Wildlife Conservation Trust
  • Daevid Mike
    School of Healthcare Sciences, Cardiff University
  • Richard Young
    Durrell Wildlife Conservation Trust
  • Michael Bruford
    School of Healthcare Sciences, Cardiff University
  • Malin Rivers
    Botanic Gardens Conservation International, Richmond, UK
  • Helen Hipperson
    NERC Biomolecular Analysis Facility
  • Isa-Rita Russo
    School of Healthcare Sciences, Cardiff University
  • David Stanton
    School of Healthcare Sciences, Cardiff UniversityQueen Mary University, London
  • William Symondson
    School of Healthcare Sciences, Cardiff University

The use of ecological replacements (analogue species to replace extinct taxa) to restore ecosystem functioning is a promising conservation tool. However, this approach is controversial, in part due to a paucity of data on interactions between analogue species and established taxa in the ecosystem.
We conducted ecological surveys, comprehensively DNA barcoded an ecosystem's flora and inferred the diet of the introduced Aldabra giant tortoise, acting as an ecological replacement, to understand how it might have modified island plant communities on a Mauritian islet. Through further dietary analyses, we investigated consequential effects on the threatened endemic Telfair's skink.
Dietary overlap between tortoises and skinks was greater than expected by chance. However, there was a negative correlation between tortoise and skink preferences in herbivory and minimal overlap in the plants most frequently consumed by the reptiles.
Changes in the plant community associated with 7 years of tortoise grazing were characterised by a decrease in the percentage cover of native herbs and creepers, and an increase in the cover of an invasive herb when compared to areas without tortoises. However, tortoise dietary preferences themselves did not directly drive changes in the plant community.
Tortoises successfully dispersed the seeds of an endemic palm, which in time may increase the extent of unique palm-rich habitat. We found no evidence that tortoises have increased the extent of plant species hypothesised to be part of a lost Mauritian tortoise grazed community.
Synthesis and applications. Due to a negative correlation in tortoise and skink dietary preferences and minimal overlap in the most frequently consumed taxa, the presence of tortoises is unlikely to have detrimental impacts on Telfair's skinks. Tortoise presence is likely to be beneficial to skinks in the long term by increasing the extent of palm-rich habitat. Although tortoises are likely to play a role in controlling invasive plants, they are not a panacea for this challenge. After 7 years, tortoises have not resurrected a lost tortoise grazed community that we hypothesise might have existed in limited areas on the islet, indicating that further interventions may be required to restore this plant community.

Allweddeiriau

Iaith wreiddiolSaesneg
Tudalennau (o-i)2245–2261
CyfnodolynJournal of Applied Ecology
Cyfrol59
Rhif y cyfnodolyn9
Dyddiad ar-lein cynnar10 Rhag 2021
Dynodwyr Gwrthrych Digidol (DOIs)
StatwsCyhoeddwyd - 1 Medi 2022
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