Can a native rodent species limit the invasive potential of a non-native rodent species in tropical agroforest habitats?
BACKGROUND
Little is known about native and non-native rodent species interactions in complex tropical agroecosystems. We hypothesised that the native non-pest rodent Rattus everetti may be competitively dominant over the invasive pest rodent Rattus tanezumi within agroforests. We tested this experimentally by using pulse removal for three consecutive months to reduce populations of R. everetti in agroforest habitat, and assessed over 6 months the response of R. tanezumi and other rodent species.


RESULTS
Following removal, R. everetti individuals rapidly immigrated into removal sites. At the end of the study period, R. tanezumi were larger and there was a significant shift in their microhabitat use with respect to the use of ground vegetation cover following the perturbation of R. everetti. Irrespective of treatment, R. tanezumi selected microhabitat with less tree canopy cover, indicative of severely disturbed habitat, whereas R. everetti selected microhabitat with a dense canopy.


CONCLUSIONS
Our results suggest that sustained habitat disturbance in agroforests favours R. tanezumi, while the regeneration of agroforests towards a more natural state would favour native species and may reduce pest pressure in adjacent crops. In addition, the rapid recolonisation of R. everetti suggests this species would be able to recover from non-target impacts of short-term rodent pest control. © 2015 Society of Chemical Industry.
Crop and Environmental Sciences Division, International Rice Research Institute, DAPO Box 7777, Metro Manila, Philippines.|School of Biological Sciences, The University of Reading, Reading, Berkshire, RG6 6AS, UK.
Alexander M
AM
Stuart
School of Biological Sciences, The University of Reading, Reading, Berkshire, RG6 6AS, UK.
Colin V
CV
Prescott
Crop and Environmental Sciences Division, International Rice Research Institute, DAPO Box 7777, Metro Manila, Philippines.
Grant R
GR
Singleton
D000818:Animals; D000069601:Crop Protection / Q000379:methods; D017753:Ecosystem; D005260:Female; D016468:Forestry / Q000379:methods; D058865:Introduced Species; D008297:Male; D010572:Pest Control, Biological / Q000379:methods*; D011157:Population Dynamics; D051381:Rats; D012375:Rodent Control / Q000379:methods*
Rattus everetti; Rattus tanezumi; interspecific competition; microhabitat use; pest management; removal experiment