Vegetation surveys and mapping of the Crinolyn and Windella Ramsar sites of the Gwydir wetlands 2023

This dataset is the Plant Community Type (PCT) mapping for the Crinolyn and Windella Ramsar sites of the Gwydir wetlands based on from the tree demographic and full floristic plot vegetation surveys undertaken by Eco Logical Australia from 12 April to 16 April 2023 under the NSW Department of Planning and Environment Gwydir Reconnecting Watercourse Country Program. Within Crinolyn, three PCTs were recorded, two of which (PCT 40 and 53) occur in two distinct forms and form the dominant vegetation communities within the site. A total of four PCTs were recorded within Windella, one of which (PCT 53) occurs in two distinct forms. Coolabah woodland (PCT 40a and 40b) occupied a considerable extent (33.02 ha combined) of Crinolyn and the presence of dead Coolabah throughout areas of PCT 53a, indicate a greater previous extent of Coolabah woodland within and surrounding the site. The extent of Coolabah woodland (PCT 40b) across Windella is less extensive, consisting mostly of patches featuring one mature tree and surrounding saplings and seedlings. PCT 182, characterised by dense stands of Typha domingensis (Narrow-leaved Cumbungi), dominates the central and southern portions of Windella. Following recent inundation, Narrow-leaved Cumbungi is widespread across the majority of the site, featuring as a measurable component of the remaining three other PCTs. A total of two tree demographic / full floristic plots and four full floristic monitoring plots were established in both the Crinolyn and Windella Ramsar sites. A total of 70 flora species (comprising 50 native and 20 exotic species) were recorded within Crinolyn full floristic plots, whilst a total of 48 flora species (comprising 33 native and 15 exotic species) were recorded within Windella full floristic plots. Condition class schemas developed for flood-dependent PCTs were applied to Crinolyn and Windella full floristic plot data. Condition class results were consistent for PCTs across both Crinolyn and Windella, with PCT 40 plots (PCT 40a and 40b) assessed as either Intermediate/Poor or Intermediate, whilst PCT 53a plots ranged from Intermediate to Good or Excellent/Benchmark and PCT 182 plots were assessed as Intermediate. A total of 45 trees were assessed within the two tree demographic plots (CRIN_3 – PCT 40b and CRIN_6 – PCT 40 a) established and surveyed within Crinolyn Coolabah woodland patches. Despite the two plots occurring in the two different forms of Coolabah woodland (PCT 40a and PCT 40b), major differences in tree condition between the two sites were not apparent. A total of 65 trees were assessed within the two tree demographic plots (WIND_2 and WIND_3 – both PCT 40 b) established and surveyed within Windella Coolabah woodland patches. Both plots recorded consistent results, reflective of the similar structure of the Coolabah woodland patches present within Windella. Landscape features or structures present within and surrounding the Crinolyn and Windella Ramsar sites which may influence inundation and hydrological regimes were noted during the field survey, most evidently drainage channels that have been constructed within both sites. Both drainage channels influence the flow of water across both sites and in doing so, also influence the distribution and composition of vegetation within the sites. Away from site boundaries, and apart from Phyla canescens (Lippia) which was widespread across both sites, weed cover was generally low and no listed weed species for the region were recorded during field surveys (Local Land Services 2017). Crinolyn and Windella Ramsar sites contain vegetation reflective of functioning wetland systems which vary in form and condition across their extent, and in addition to their individual ecological value, are an important part of the wider Gwydir Wetlands. At a broader scale, the separation of the sites from one another and surrounding wetlands is apparent, as is the influence of external factors such as the scale and intensity of surrounding land use. The vegetation and conditions within both sites at the time of field surveys were typical of a recent ‘wet’ period and may contrast considerably with ‘dry’ period conditions. Given this, there may be value in assessing condition changes across both sites through remote sensing and a follow up ‘dry period’ field survey. It is also recommended that a revision of the boundaries of both Crinolyn and Windella Ramsar sites be undertaken in order to maximise the extent of remnant vegetation and overall ecological value of both sites.