The Living Murray Condition Monitoring at Lindsay, Mulcra and Wallpolla Islands 2009/10

"March 2011".Project Number: 2009-10 Condition Monitoring at Lindsay-Mulcra-Wallpolla Islands - M/BUS/87-2,3,4 BW283.MDFRC item.This report details the condition monitoring undertaken at Lindsay, Mulcra and Wallpolla (LMW) Islands as part of the 2009/10 Living Murray Condition Monitoring Program. Icon Site condition monitoring has been developed to: Determine the change in environmental condition of individual assets resulting from water application and the implementation of works programs under The Living Murray (TLM). Assess whether sustainable native fish, bird and vegetation communities are being maintained across the Icon Sites. The Outcomes Evaluation Framework stipulates that measurable targets be created to unambiguously assess whether a pre-determined level of condition has been achieved. At the time of writing, such targets had not been developed for LMW. In the absence of defined targets, this report focuses upon Icon Site specific objectives. Icon Site specific objectives presented in the Outcomes Evaluation Framework have been further refined as part of the Lindsay-Mulcra-Wallpolla Environmental Management Plan. Together these objectives form the basis for condition monitoring at Lindsay-Mulcra-Wallpolla of which there are six vegetation components and one fish component. River Red Gum The ecological objectives for River Red Gum (RRG) at Lindsay, Mulcra and Wallpolla are: Current area maintained. Maintain current condition and extent of River Red Gum communities to sustain species assemblages and processes typical of such woodland. Large scale mapping at regular intervals is required to quantify changes in the distribution and areal extent of River Red Gum at LMW. Currently there is no such mapping program underway, so it is not possible to know if current area of RRG is being maintained. Significant increases in Crown Condition scores between the sampling events of 2008/09 and 2009/10 suggest changes in the conditions favourable for tree growth on the LMW floodplain. This is attributed to environmental watering at Mulcra Horseshoe Lagoon and a break in drought conditions. However, with the notable exception of the relatively small area of extant Red Gum with Flood Tolerant Understorey (RGFTU) at Mulcra Island, the recent improvement observed for RRG trees at LMW represents a change in the previous downward trend in condition rather than a return to acceptable condition. Stand condition modelling conducted by Cunningham et al.(2009) reports that the extent of severely degraded stands was higher in the Mallee (Hattah, Chowilla and LMW) than at other TLM Icon Sites, that the majority of stands were in a stressed condition in 2003 and that this had increased by 4% by 2009. Recruitment must keep pace with mortality for a population to remain sustainable and this must occur within the current spatial context if the present distribution is to be maintained (i.e. ecological objectives are to be met). Size-class frequency distributions for Fringing Red Gum Woodland (FRGW) indicate a relative abundance of trees within the smaller size classes suggesting sustainable recruitment. However, despite indications of recent improvement in the condition of trees on average, population viability assessments suggest there are long-term sustainability concerns for Red Gum Forest (RGF) communities at LMW. Black Box The ecological objectives for Black Box (BB) at LMW are: At least 20% of the original area of Black Box vegetation maintained. Improve condition to sustain species assemblages and processes typical of Black Box woodland. Ecological Vegetataion Class (EVC) mapping conducted in 2005 provides the most accurate and up to date information about the areal extent of Black Box at LMW and is therefore the logical choice for a BB areal standard. However, in the absence of an ongoing program mapping the distribution of Black Box at the Icon Site scale, it is not possible to know what proportion of the original area of Black Box is being maintained. Size-class distributions for Black Box communities do not approximate inverse J-shaped curves indicative of sustainable populations. Further, between 2008/09 and 2009/10 there was a reduction in the relative proportion of Diameter at Breast Hight (DBH) 16 ds/m, DPI 2008) and an increase in abundance could be indicative of an increase in site salinity. It is recommended that soil salinity testing be undertaken at the LMW Icon Site. Of concern are the appearances and/or incr