Invasive rats on tropical islands: Their population biology and impacts on native species

By G. Harper, N. Bunbury. 2015

280 citations recorded by the source corpus.

Abstract The three most invasive rat species, black or ship rat Rattus rattus, brown or Norway rats, R. norvegicus and Pacific rat, R. exulans have been incrementally introduced to islands as humans have explored the world’s oceans. They have caused serious deleterious effects through predation and competition, and extinction of many species on tropical islands, many of which are biodiversity hotspots. All three rat species are found in virtually all habitat types, including mangrove and arid shrub land. Black rats tend to dominate the literature but despite this the population biology of invasive rats, particularly Norway rats, is poorly researched on tropical islands. Pacific rats can often exceed population densities of well over 100 rats ha−1 and black rats can attain densities of 119 rats ha−1, which is much higher than recorded on most temperate islands. High densities are possibly due to high recruitment of young although the data to support this are limited. The generally aseasonally warm climate can lead to year-round breeding but can be restricted by either density-dependent effects interacting with resource constraints often due to aridity. Apparent adverse impacts on birds have been well recorded and almost all tropical seabirds and land birds can be affected by rats. On the Pacific islands, black rats have added to declines and extinctions of land birds caused initially by Pacific rats. Rats have likely caused unrecorded extinctions of native species on tropical islands. Further research required on invasive rats on tropical islands includes the drivers of population growth and carrying capacities that result in high densities and how these differ to temperate islands, habitat use of rats in tropical vegetation types and interactions with other tropical species, particularly the reptiles and invertebrates, including crustaceans.

Subfields: Ecology, Nature and Landscape Conservation

View Paper: https://www.semanticscholar.org/paper/2d8caef02e4633bf5f61bf771d19f3206a1fa1fd

How researchers see this paper

The researchers whose trusted networks rank it highest, strongest advocate first. Every researcher gets a different order.

In Ecology

In Nature and Landscape Conservation

Citations in the corpus

Population impacts of free‐ranging domestic cats on mainland vertebrates (2017, background): “…of invasive rats (Rattus spp) on many islands around the world has led to the extinction or decline of many amphibians, reptiles, and birds (Harper and Bunbury 2015), and the introduction of the invasive red fox (Vulpes vulpes) in Australia has contributed to the extinction of several rat-…”
Application of the Environmental Impact Classification for Alien Taxa (EICAT) to a global assessment of alien bird impacts (2016, background): “This may be because islands are more susceptible to impacts associated with alien species (Pearson, 2009; CBD, 2015; Harper & Bunbury, 2015), and the severity of their impacts has resulted in higher levels of research there.”
Which Traits Influence Bird Survival in the City? A Review (2021, background): “For example, an increase in rodent populations on islands has led to the extinction of several island dwelling birds and other fauna [190].”
The threat of invasive species to IUCN-listed critically endangered species: A systematic review (2021, background): “, 2016a; Johnson and Stattersfield, 1990), with a continuing steady decline (Blackburn, 2004; Clavero et al., 2009; Harper and Bunbury, 2015; Bellard et al., 2016b, 2017), especially of seabirds (Jones et al.”