Monitoring of Tasmania's inshore reef marine ecosystems. An assessment of the potential for volunteer monitoring programs and summary of the changes within the Maria Island marine reserve between 1992-2001

Abstract

Analysis of the results of the long-term monitoring was restricted to notable changes occurring within the largest Tasmanian coastal MPA at Maria Island. After nine years of protection at the Maria Island MPA, mean size of lobsters was significantly greater than in the surrounding fished waters and still increasing. The total abundance of lobsters now appeared to be relatively stable following a threefold increase during the first five years of protection. The mean size of abalone continued to slowly increase, while the abundance of abalone appeared to have declined by 50% over the nine years.. This decline may be due to several causes, including an increase in predator density (eg. lobsters and large fishes) and increased competition resulting in delayed emergence or higher mortality. Urchin abundance has declined by up to 40% and may also be related to increased levels of predation. The monitoring has revealed shifts in species distributions that may be related to long-term oceanic cycles, and patterns in the invasability of an introduced macroalgae Undaria pinnatifida. Monitoring by community based volunteers demonstrated that with a limited level of training on species identification and quantitative techniques, volunteer groups could provide data that were sufficiently reliable to characterise a “place” at a particular point in time with respect to the assemblage present. While the results of individual divers were highly variable, pooling results of volunteers at each location produced a result similar to that obtained by skilled observers. At an individual species level, or for estimation of the mean size of individual species, the volunteer data was less reliable than that provided by skilled researchers, however, with sufficient training volunteer data may show significant improvement. An essential component of community involvement is to ensure adequate training and feedback for all divers, that events are well coordinated, and adequate post dive support is on hand to ensure species are identified and recorded accurately and legibly. With good training and professional facilitation of volunteers, community based monitoring may provide data with sufficient reliability to detect substantial shifts in reef ecosystems. However, unless this is organised on a large scale by volunteer organisations, logistical constraints mean data obtained by this method are likely to be substantially less cost effective or reliable than that obtained by research organisations with adequately trained staff.