Successful survey for a poorly-known weta, Hemiandrus sp. 1 (Orthoptera: Anostostomatidae), based on a GIS-generated environmental envelope.

Abstract

In addition to the nine described species of ground weta (Hemiandrus Ander 1938) in New Zealand, there appears to be a further 28 unnamed taxa. One of these, Hemiandrus sp. 1 (tag-named Hemiandrus ‘Waimakariri’), was only known from one specimen found in the Poulter Valley, Arthurs Pass National Park, in the late 1960's. Insuffi cient information is available to assign a threat ranking to this taxon, and it is currently categorised as Data Defi cient. To direct survey effort and in an attempt to provide additional information on distribution, environmental envelopes were constructed using Geographic Information Systems (GIS) that predicted other sites where Hemiandrus sp. 1 may be present. These envelopes were based on the values of the environmental layers used to create the Land Environment of New Zealand (LENZ). Survey sites were selected from within these environmental envelopes and a combination of night searching and pitfall trapping was undertaken to validate Hemiandrus sp. 1 presence. During this survey four specimens were found near Lake Lyndon, bringing the total number of known specimens to five, and expanding the previously known distribution. This technique has applicability for other species with poorly known distributions.

Keywords:

• Weta
• geographic information systems
• threat status
• Canterbury
• New Zealand