Data for the project investigating movement of terrestrial rodents in riparian reserves

The spool-and-line technique was used to observe the efficacy with which small mammals are able to use riparian strips as dispersal corridors within a fragmented landscape. I set up transects along established riparian strips in mature oil palm plantations, using novel sites >1000m away from existing SAFE project sites to avoid conflict with other projects. These included riparian strips of widths ranging from 10-120 metres. Control (continuous twice-logged forest) sites will be set up within the SAFE landscape. For each riparian transect, I set twenty Tomahawk-style steel cage traps baited with oil palm fruit at 15m intervals along the transect, with a constant distance from the oil palm edge of the riparian zone. To avoid physiological stress to the mammals, traps were set up only in well-shaded microhabitats in dense cover, with sufficiently large and fresh bait to provide adequate nutrition. I checked trapping transects everyday and re-set each day at dusk. This study will focus on common and resilient rats of the genus Maxomys. I only focus on adults and subadults, and released vulnerable juveniles and pregnant females released. Animals caught were identified, sexed and aged, and either released or retained for tracking, depending on several criteria. Spooled individuals will fit weight criteria such that any attached spool device does not exceed 5% of the individual's body weight. Animals over 40g were tracked with a small spool (length=88m), while animals over 100g will use a large spool (length=220m). Animals below the 40g cut-off were released. This ensures representative movement is observed, and meets widely-accepted ethical guidelines for tracking devices. Animals fitted with a spooling device were firstly anaesthetised with diethyl ether to obtain biometric measurements (hind foot, ano-genital distance and weight), the sex, age and species for each individual. As well as providing back-up information in the case of uncertain ID, these data are important covariates of observed movement behaviour. To track the movement path of selected individuals, I attached a temporary lightweight bobbin of thread to the animal. A hair clip will be taken from the upper back region to provide a fur-based attachment point for the spool using cyanoacrylate gel glue. To spool package was a bobbin double-wrapped in a cling-film layer that allows smooth unravelling, and then wound in a gaffer tape layer that avoids snagging on foliage. The total weight of the package did not exceed 5% of the average minimum weight of each species. Once processed, I translocated individuals from their site of capture by ~50m to a release site longitudinally along the same riparian reserve. The proximal end of the thread was tied to a fixed or heavy structure such as the trap so that as the animal is released from the trap, the freely unravelling thread catches onto vegetation and topography, revealing the movement patterns of the individual. Movement paths were divided into steps, with a step being defined as a length of the animal's track where it does not deviate from a straight line by more than 10 degrees. I measured the length of steps and the angles between them using a tape measure and compass to construct a detailed two-dimensional map of each animal's route through space. From this, I obtained a measure of path tortuosity (fractal dimension and deviation from a correlated random walk) for each tracked movement path.

Authors

• Gutierrez Al-Khudhairy, Selene — Imperial College London
• Ewers, Robert M. — Imperial College London

Keywords

• Rodents
• Riparian Reserves
• Continuous twice-logged forest

Funders

• No funders recorded.

Permits

• No permits recorded.

Worksheets

Files

• template_Gutierrez_TerrestrialRodentMovementRiparian.xlsx

Taxa

20 GBIF taxa, 0 sequence-derived taxa.