Developing a database of Australian grasshopper occurrences from historic field survey notebooks spanning 54 years (Orthoptera: Acrididae, Morabidae, Pyrgomorphidae, Tetrigidae)

Abstract

The baseline distribution data for all species of a given group in a region can provide fundamental insights into biogeographic questions about historic patterns of species richness, population trends and extinction. Grasshoppers are one major group of insects for which a continent-wide perspective on their geographic distribution can be obtained. This is because they were extensively surveyed in Australia for 54 years as part of Commonwealth expeditions to obtain specimens for the Australian National Insect Collection (ANIC). Field notebooks recorded from those surveys, under the direction of ANIC curator and director K. H. L. Key, form the principal source of historic distribution records for grasshoppers in Australia. We digitised all the 223 notebooks (2486 pages) and transcribed all the field trips conducted in Western Australia (WA) and Tasmania (47 notebooks, 590 pages). We then carefully geocoded all sampling sites of the transcribed notebooks, following the odometer readings and descriptions of routes from a suitable reference point using historic topographic maps and Google Earth. In total, we extracted 8975 geographic coordinates for 477 species having a confirmed or putative taxonomic name at genus or species level (only 170 of these species have been formally described). We found that species richness varied spatially, with highest richness in arid interior and north of WA. Historic grasshopper surveys were non-randomly distributed across both WA and Tasmania with the highest survey intensity around coastal regions. Variation was observed among surveyors in terms of the number of species detected per site, between-site distance and the season of survey being conducted. Overall, however, the dataset is among the most comprehensive continent-wide surveys of Australian invertebrates and will greatly facilitate future work on their ecology, biogeography, conservation and responses to environmental change.

Leveraging historical field notebooks to uncover continental‐scale patterns in the diversity of Australian grasshoppers

“…We focus on the Australian state of Western Australia, where our initial transcription and geocoding efforts have been targeted (Hossain et al, 2023). This large region (2.6 million km 2 ) encompasses a wide range of climates from cool, humid, and winter-dominant rainfall in the south-west, sparse, aseasonal rainfall in the arid interior, and summer rainfall in the tropical north.…”

“…The historic field notebooks of Key and associates and their transcription were detailed in (Hossain et al, 2023). Briefly, each notebook contains systematic details of the route of travel, distance recorded by vehicle odometer, and collection stops (identified from suitable geographic references, e.g., towns, creeks, road-junction).…”

“…However, within Australia, large regions are also recognised as centres of endemism (Crisp et al, 2001;Slatyer, Rosauer, & Lemckert, 2007). While a few species of grasshoppers are widely distributed and cause periodic outbreaks, many species were very rarely recorded (Hossain et al, 2023) and can likely be regarded as shortrange endemics within Australia. Because the measure of endemism is dependent on scale, we used weighted endemism (WE) following Crisp et al (2001), Slatyer, Ponder, et al (2007) and others.…”

“…In addition, for each collection stop they recorded a general description of the site, common plants in the area, soil type, topography, grasshoppers observed which are often associated with life stages and their relationship with plants. For each site, they spent approximately 30 min of collecting grasshoppers by sweep net and bush shaking/beating and through visual inspection of the vegetation and ground layer (Day & Rentz, 2004;Hossain et al, 2023). We obtained geographical coordinates from Google Earth by following the route directions recorded in the field notebooks with the aid of historic topographic maps.…”

“…For grasshoppers, Dr Ken H.L. Key and his colleagues conducted 223 field surveys in Australia along the road networks for over 54 years (mostly a single visit to each site), from 1936 to 1989 (Hossain et al, 2023;Kearney et al, 2021). Specimens collected from these field notebooks are preserved in the Australian National Insect Collection.…”