Invasive rat eradication strongly impacts plant recruitment on a tropical atoll

PLoS One. 2018 Jul 17;13(7):e0200743. doi: 10.1371/journal.pone.0200743. eCollection 2018.

Abstract

Rat eradication has become a common conservation intervention in island ecosystems and its effectiveness in protecting native vertebrates is increasingly well documented. Yet, the impacts of rat eradication on plant communities remain poorly understood. Here we compare native and non-native tree and palm seedling abundance before and after eradication of invasive rats (Rattus rattus) from Palmyra Atoll, Line Islands, Central Pacific Ocean. Overall, seedling recruitment increased for five of the six native trees species examined. While pre-eradication monitoring found no seedlings of Pisonia grandis, a dominant tree species that is important throughout the Pacific region, post-eradication monitoring documented a notable recruitment event immediately following eradication, with up to 688 individual P. grandis seedlings per 100m2 recorded one month post-eradication. Two other locally rare native trees with no observed recruitment in pre-eradication surveys had recruitment post-rat eradication. However, we also found, by five years post-eradication, a 13-fold increase in recruitment of the naturalized and range-expanding coconut palm Cocos nucifera. Our results emphasize the strong effects that a rat eradication can have on tree recruitment with expected long-term effects on canopy composition. Rat eradication released non-native C. nucifera, likely with long-term implications for community composition, potentially necessitating future management interventions. Eradication, nevertheless, greatly benefitted recruitment of native tree species. If this pattern persists over time, we expect long-term benefits for flora and fauna dependent on these native species.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Animals
  • Biodiversity
  • Cocos / physiology*
  • Conservation of Natural Resources*
  • Ecology
  • Ecosystem*
  • Hawaii
  • Introduced Species*
  • Islands
  • Pacific Ocean
  • Rats
  • Seedlings
  • Trees / physiology*
  • Tropical Climate

Associated data

  • Dryad/10.5061/dryad.hv58f

Grants and funding

This research was funded by Island Conservation (https://www.islandconservation.org/; DC and BT), the US Fish and Wildlife Service (https://www.fws.gov/; NH and AW), National Fish and Wildlife Foundation (http://www.nfwf.org/Pages/default.aspx; NH), David and Lucile Packard Foundation (https://www.packard.org/; NH), Moore Family Foundation (NH), National Geographic Society (https://www.nationalgeographic.com/; RD and HY), The Nature Conservancy (https://www.nature.org/; AW), and the National Science Foundation (https://www.nsf.gov/; HY). The funding sources financially supported the data collection and writing of this report but did not have any other involvement in the study design data collection and analysis, decision to publish, or preparation of the manuscript. The views and conclusions contained in this document are those of the authors and should not be interpreted as representing the opinions or policies of the U.S. Government or the National Fish and Wildlife Foundation. Mention of trade names or commercial products does not constitute their endorsement by the U.S. Government or the National Fish and Wildlife Foundation.