LTERN Data Portal

The network program uses a core of 12 sites which are spaced at least 15 km apart, each comprising two 1-ha trapping grids, or plots which are spaced between 0.5-2 km apart. Each of the 24 trapping grids is set out with thirty-six traps arrayed in a grid covering 1 ha; each grid comprises 6 lines of 6 traps spaced 20 m apart. The top line of traps extends along the dune crest, where consecutive numbering starts, and finishes along the sixth line 100 m distant in the dune valley or ‘swale’. Traps on each grid are opened for 1–6 nights (usually 3), approximately four times per year and checked in the mornings and sometimes afternoons, and animals are removed for processing.

Herpetofauna are captured in pitfall traps. Each pitfall is made from PVC stormwater pipe, 160 mm in diameter and 600 mm deep, sunk vertically into the ground so that its top is flush with ground level. To increase trap success, by intercepting and guiding surface-active animals into the trap, a drift fence of aluminium wire mesh (flyscreen) extends outwards from the top of each trap, secured in place by means of a shallow trench. The fence is 30 cm high and runs for 2.5 m on each side of the pitfall opening. The bottom end of the pit is covered with flyscreen to form a floor to prevent captured animals from digging their way out, and all pits are capped with metal lids when not in use. A tiny amount of insecticide (Coopex) is sprinkled around each trap to prevent ant attack.

• Pitfalls must be dug into the ground, so that the lip of the pipe is level to the ground, this can be done using a shovel. Wire mesh drift fence is bent at about 10 cm to form an L-shape and dug into the ground and pulled straight and upright.

• Open all 36 pits using a spoon or pocket screwdriver

• Make sure the mesh is directly over the open pit and there is no a lip as reptiles can use it as a bridge over the pit and don’t get caught.

• Empty out excess sand from all pits .

• Sprinkle Coopex around the edge of each pit to deter ants.

• Check pitfall traps in the cool of the early morning to reduce stress on the animal.

• Thoroughly check each pitfall, first by visually ensuring that there is not a snake or other venomous animal inside the pit. Once certain that it is safe, cover hand with calico trapping bag and stick arm down pit and feel around for any mammals or reptiles, carefully sift through the sand as Leristas and other small lizards are hard to see. Leather gloves can be worn for extra protection against bites and scratches.

• Remove any invertebrates from the pit, such as scorpions and centipedes and release at point of capture.

• Be careful when removing animals from pitfalls, do not grab any animal by the tail. Place bag over animal and invert it inside pit to safely secure animal.

• Place each animal in a separate calico bag and tie the top tightly to avoid escapes. Write trap and grid number on bag with permanent marker to ensure animal can be relased at point of capture after processing. Store the animals in large calico bag.

• Once all traps are checked, animals are processed on site and released at point of capture.

• At the end of the trapping survey (on the third day), place metal lids firmly on pitfall trap and ensure lid sits tight. Cover lid with a bit of sand to reduce exposure to sunlight and curious animals

Date, site and grid number were recorded for all captures, and captured animals were also marked with unique ID numbers allowing identification of recaptured animals.