Open Access

J. S. Benson, E. M. Ashby

• The remnant natural vegetation (excluding native grasslands) of the Guyra 1: 100 000 map sheet area was sampled by way of 312 20 m × 20 m plots in which all vascular species were recorded using a modified Braun-Blanquet abundance rating. Sampling was stratified to cover the environmental factors of substrate, topographic position and altitude. Floristic analyses used the Kulczynski coefficient of dissimilarity in an agglomerative hierarchical cluster analysis and multidimensional scaling ordinations. Twenty-one plant communities were selected from the cluster analysis. The contribution of species to these groupings was investigated using a fidelity analysis. Another three communities were distinguished from aerial photographs and field traverse. These 24 plant communities are described and all except riparian vegetation are mapped. Their extent was mapped using aerial photography and ground traverses. The vegetation map was digitised at a scale of 1:25,000 but has been reduced to 1:100,000 for this publication. The minimum area mapped is 1 ha. Eight hundred and eighty-nine plant taxa are reported for the study area, 681 of which were recorded during the survey. Common families are Poaceae, Asteraceae, Fabaceae, Myrtaceae, Orchidaceae and Cyperaceae. The status of the 28 nationally or State listed rare or threatened plant species, and other regionally rare species recorded in the area, is discussed. Some plant communities, such as those dominated by the stringybarks Eucalyptus caliginosa and Eucalyptus laevopinea, are ubiquitous in the landscape. Other communities are restricted in their geographic extent and contain a distinct suite of species. These included heath swamps, some forests on leucogranite and wetland vegetation in lagoons on basalt plateaux. 74% of the native woody vegetation has been cleared. This has particularly affected plant communities on higher nutrient soils including Eucalyptus viminalis and Eucalyptus dalrympleana subsp. heptantha open forest on basalt plateaux, Eucalyptus nova-anglica woodland in valleys, and Eucalyptus blakelyi and Eucalyptus melliodora woodland on sediments at lower altitudes. Most of the remnants have been grazed by stock thus influencing the understorey structure and species composition. Upright forbs and Acacia would appear to be less common now than prior to European settlement. Dieback of eucalypts over the last two decades has compounded the impacts of clearing. Logging and firewood cutting affects some plant communities. Weeds are most invasive where understorey disturbance is greatest, which is mainly in the small remnants on higher nutrient soil (basalt and sediments). Most of the lagoons in the study area have been drained or impounded, thus depleting wetland vegetation. Changes to fire regimes in the forest remnants may also have altered the populations of fire-dependent species. Most of the plant communities are poorly represented in conservation reserves. Conservation initiatives on private land are required to protect most of the communities. Key sites for conservation are listed.