BugWise

BugWise volunteer, Pierre Louys (foreground) at a BugWise workshop. Photo: J Gollan © J Gollan.

About the Wards River Project 

Pierre Louys—owner/land manager in the Wards River area—has removed weeds and other non-native plants (mostly lantana) from a number of plots on his property. The native vegetation on Pierre’s property is in good condition, but he hopes that removing non-natives will have a positive impact on native fauna and improve the value of his property further. Pierre attended a BugWise workshop at Tocal in November and was keen to apply his skills. The BugWise team assisted Pierre in collecting data (using Web2Spider) in three sites: (1) where lantana had not been removed; (2) where lantana had been removed, and (3) an area in the nearby Barrington Tops National Park where the vegetation is considered in good condition and no lantana present. This project aids in the understanding of the impact of weed invasion on web-building spider communities.

Results and Discussion

Surveys were conducted over two days (5 and 6 May, 2008). A total of 612 webs were counted, the majority of which (49%), were found in sites where lantana had been removed. A total of sixteen different webs types were found, 14 of which were found in the national park sites and 13 in the sites where lantana had been removed. Only 6 web types were found where lantana had not been removed. The most common web type found was W19 (40% of total abundance) followed by W27 (32% of the total abundance). Three web types (W4, W9, W23) were unique to National Park sites, while all 6 web types found at sites where lantana was present, were present at either sites where lantana had been removed or those in the National Park.

These surveys indicated that removing lantana was beneficial for richness of web-building spiders since diversity was similar to sites in National Parks, but different to those where lantana had not been removed (See figures below). Somewhat surprisingly, the number of webs at National Park sites was similar to sites with lantana, with abundance being much greater at sites where lantana had been removed (See figures below). This may have been a response to the disturbance of weed removal, but more work is needed to explore this explanation.