BugWise member, Colleen Gillen. Photo: J Gollan © J Gollan.
Web2Spider being used along a rehabilitated section of the Allyn River
Colleen Gillen and her husband Jai, are managers of a property at East Gresford. For several years, Colleen and Jai’s family have been rehabilitating a 2.5 km section of land along the Allyn River in the Upper Hunter Catchment. Work has involved replanting native riparian species, but also removing weeds such lantana and giant reed. Colleen attended a BugWise workshop at Tocal in November 2007 and was keen to have her family involved with BugWise and apply the new skills she learnt. With assistance from the BugWise team, web richness and abundance was compared between sites where there had been no previous attempts at rehabilitation (Grassland), and sites where rehabilitation attempts had been made.
Results and Discussion
Surveys were conducted over a single day in early May 2008. The most common web type in rehabilitated sites was W17 (35% of total) while W32 accounted for the majority of the total in grassland sites (34%). A total of 228 webs (40 in grassland sites and 188 in rehabilitated sites) and 10 different web types were recorded (9 in grassland sites and 10 in reference sites). Nine web-types (W2, W14, W17, W18, W19, W23, W25, W30, W32) were found in grassland and rehabilitated sites, and only one was unique to rehabilitated sites (W22). While mean diversity was higher at rehabilitated sites than grassland sites, variability indicated that there were no real differences between the two habitat types (See figures below). Contrarily, there were large differences in the total number of webs between the two habitat types
From these results, removing weeds and planting natives appears beneficial for web-building spider assemblages. While there were no large differences between the two types of site in terms of diversity, there were obvious differences in terms of their abundance. The close proximity of the two sites probably explained the patterns in terms of their similar diversity. It is likely that the rehabilitated site is acting as an important source of recruitment to other areas.
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