Lake Yando Post-Watering Vegetation Assessment

"June 2010".

Project Number: Post-watering vegetation condition assessment for Lake Yando - M/BUS/347.

MDFRC item.

This document reports on the results of a vegetation survey which was carried out at Lake Yando in March 2010. Lake Yando is an 83 Ha wetland, located approximately nine kilometres north-east of Boort, Victoria. The wetland filled historically from Venables Creek and in years of larger floods, would have received water from Kinypanial Creek via Lake Boort, as well as Lake Lyndger (NCCMA 2010). Development of irrigation infrastructure in the region led to changes in the wetland flooding regime with connection to the irrigation system causing Lake Yando to become flooded with irrigation outfall water for prolonged periods of time (NCCMA 2010). This increased water permanence contributed to substantial changes in vegetation structure and composition at Lake Yando, including the death of established River Red Gum (Eucalyptus camaldulensis) trees across the wetland base and an increase in the extent of Cumbungi (Typha spp.) stands (NCCMA 2010). Modifications to the water delivery system around 1999 have allowed Lake Yando to dry completely in recent years. Management of the site is currently focused on the reinstatement of a more natural flooding regime, including alternating wet and dry phases. This is designed to support the environmental values of the wetland. A specific environmental watering plan (EWP) is being developed for Lake Yando, as well as a number of other wetland and waterway sites, as part of the Northern Victorian Irrigation Renewal Project (NVIRP). As part of the EWP development process, the vegetation at Lake Yando was surveyed by The Murray-Darling Freshwater Research Centre (MDFRC) staff in October 2009. This survey was conducted to obtain baseline data on vegetation composition, condition and distribution that could be used to identify vegetation water requirements and set watering targets. To maintain and/or improve the integrity of the vegetation community at Lake Yando the recommended goal proposed by NCCMA (2010) was: ‘To provide a watering regime typical of a deep freshwater marsh that supports the maintenance and recruitment of River Red Gum and promotes the growth of a diverse range of aquatic and amphibious plant species offering a variety of habitats to waterbirds, reptiles and amphibians.’ In October 2009 water was delivered to Lake Yando to meet a number of ecological objectives, including those specific to vegetation, as summarised in the goal statement above. The survey reported on here was used to assess how the recent watering event has affected the vegetation community at Lake Yando and to determine whether progress is being made toward achieving the objectives proposed by NCCMA (2010).