Treeless vegetation of the Australian Alps

Based on 1222 floristic quadrat samples, 56 plant communities were identified in treeless vegetation in the Australian Alps of south-eastern Australia. (c. 35º 30´–38ºS, 146°–149°E). The study encompassed vegetation from above the upper limit of trees on mountain tops (i.e. the truly alpine environment) and below the inverted treeline in subalpine valleys. Generally, grasslands develop on deep humus soils, heathlands occur on shallower or rocky soils, and wetland communities are found in places of permanent or intermittent wetness. Duration of snow cover, lithology, altitude and exposure are also important determinants of the spatial arrangement of communities. Broadly, communities within a geographic region are more closely related to each other than to communities of similar structure or dominants from other geographic areas. Many communities are either very localised or are widespread with a small area of occupancy. Fourteen communities are probably eligible for listing as threatened, either alone or as aggregates with associated communities. A total of 710 native taxa from 82 families has been recorded. There is a high level of endemism – 30% of taxa are ± restricted to treeless vegetation in the Australia Alps and a further 14% are ± restricted to treeless vegetation but occur in mountain areas outside the Australian mainland (e.g. Tasmania and New Zealand). Thirteen taxa are listed in the Environment Protection and Biodiversity Conservation Act 1999 as threatened and a further 18 taxa are identified that may be eligible for listing as threatened nationally. 131 non-native taxa have been recorded in natural vegetation. Treeless vegetation has been intensively utilised since European settlement, initially as summer pastures for cattle and sheep but more recently as water catchments for electricity production and as tourist attractions both in winter and summer. Many communities are slowly recovering from past pressures and from the fires of 2003, which burnt most of the area for the first time since 1939. The treeless vegetation of the Australian Alps faces an uncertain future because of increased pressure from tourism and the unknown impacts of global warming

Spatial Analysis of Risks Posed by Root Rot Pathogen, Phytophthora cinnamomi:Implications for Disease Management

Phytophthora cinnamomi, a soil-borne pathogen that infects the roots of plants, is listed as a Key Threatening Process under Commonwealth and NSW state biodiversity legislation due to its deleterious effects on native flora. In warm temperate eastern Australia, the disease may cause insidious declines in plant species that have slow rates of population turnover, and thereby threaten their long term persistence. Phytophthora cinnamomi has been known to occur in Royal National Park since the 1970s and systematic surveys for the pathogen were carried out a decade ago. Development of effective management strategies to mitigate the impacts of the disease requires information on the spatial distribution of risks posed by the disease. In this study, we use limited disease survey data to identify areas that are most at risk. We propose and apply a simple risk model in which risks of disease impact are proportional to the product of habitat suitability for the pathogen and abundance of susceptible biota. We modelled habitat suitability of the pathogen from available survey data and found that soil landscapes and topographic variables were the strongest predictors. Susceptible flora were concentrated on sandstone plateaus. Disease risks were greatest on the sandstone plateaus and lowest in the shale gullies with intermediate levels of risk on shale ridges and the coastal sand plain. The outcomes of this spatially explicit risk assessment will help inform the development of management strategies and priorities for the disease in the Park. Our approach lends itself to broader application to conservation planning in other landscapes and to other threats to biodiversity

Archiving the Scientific Legacy of Dr. Alec Costin

Alec Costin is one of Australia’s foremost ecologists, internationally respected for his pioneering work into the soils, hydrology and vegetation of the Australian alpine regions. Advisor to governments and their agencies, he was instrumental in the conservation of the Australian Alps. Alec’s field notes, data sheets and Kodachrome slides, a record of the Alps in the 1950s and 60s, are important historically and provide an important resource to interpret change in vegetation and landscapes in the Australian Alps. The University of Melbourne, funded by the Australian Alps National Parks, will catalogue and archive these materials, so future generations of scientists and historians can easily gain access to them

Predicting species and community responses to global change using structured expert judgement : an Australian mountain ecosystems case study

Conservation managers are under increasing pressure to make decisions about the allocation of finite resources to protect biodiversity under a changing climate. However, the impacts of climate and global change drivers on species are outpacing our capacity to collect the empirical data necessary to inform these decisions. This is particularly the case in the Australian Alps which has already undergone recent changes in climate and experienced more frequent large-scale bushfires. In lieu of empirical data, we used a structured expert elicitation method (the IDEA protocol) to estimate the abundance and distribution of nine vegetation groups and 89 Australian alpine and subalpine species by the year 2050. Experts predicted that most alpine vegetation communities would decline in extent by 2050; only woodlands and heathlands are predicted to increase in extent. Predicted species-level responses for alpine plants and animals were highly variable and uncertain. In general, alpine plants spanned the range of possible responses, with some expected to increase, decrease or not change in cover. By contrast, almost all animal species are predicted to decline or not change in abundance or elevation range; more species with water-centric life-cycles are expected to decline in abundance than other species. While long-term ecological data will always be the gold-standard in informing the future of biodiversity, the method and outcomes outlined here provide a pragmatic and coherent basis upon which to start informing conservation policy and management in the face of rapid change and paucity of data

Think globally, measure locally: The MIREN standardized protocol for monitoring plant species distributions along elevation gradients

Climate change and other global change drivers threaten plant diversity in mountains worldwide. A widely documented response to such environmental modifications is for plant species to change their elevational ranges. Range shifts are often idiosyncratic and difficult to generalize, partly due to variation in sampling methods. There is thus a need for a standardized monitoring strategy that can be applied across mountain regions to assess distribution changes and community turnover of native and non-native plant species over space and time. Here, we present a conceptually intuitive and standardized protocol developed by the Mountain Invasion Research Network (MIREN) to systematically quantify global patterns of native and non-native species distributions along elevation gradients and shifts arising from interactive effects of climate change and human disturbance. Usually repeated every five years, surveys consist of 20 sample sites located at equal elevation increments along three replicate roads per sampling region. At each site, three plots extend from the side of a mountain road into surrounding natural vegetation. The protocol has been successfully used in 18 regions worldwide from 2007 to present. Analyses of one point in time already generated some salient results, and revealed region-specific elevational patterns of native plant species richness, but a globally consistent elevational decline in non-native species richness. Non-native plants were also more abundant directly adjacent to road edges, suggesting that disturbed roadsides serve as a vector for invasions into mountains. From the upcoming analyses of time series, even more exciting results can be expected, especially about range shifts. Implementing the protocol in more mountain regions globally would help to generate a more complete picture of how global change alters species distributions. This would inform conservation policy in mountain ecosystems, where some conservation policies remain poorly implemented

Vegetation patterns in the northern jarrah forest of Western Australia in relation to dieback history and the current distribution of Phytophthora cinnamomi

Dieback, largely attributed to the fungal plant pathogen Phytophthora cimiamomi, is characterized in the northern jarrah forest by multiple deaths of many plant species, including the dominant, Eucalyptus ruarginata (jarrah), a species of great commercial importance. The wide host range of the pathogen has major implications for the biodiversity of the ecosystem. The first records of dieback in the jarrah forest were made in the 1920s. Despite the magnitude and long history of the impact in the jarrah forest, little is known about the vegetation changes that result from dieback. In this dissertation, I develop a model of vegetation change related to dieback by examining the vegetation of a range of dieback sites and relating the patterns identified to the current distribution of P. cinnamomi. The study is the first explicit investigation of floristic and structural patterns on dieback sites in the jarrah forest. Substantial floristic differences were found between dieback and unaffected vegetation. The patterns are strongly correlated with the age of the original dieback event. There was little difference, however, in the mean number of species/quadrat between dieback and unaffected vegetation. The time since the inception of dieback was estimated using aerial photography. The oldest dieback sites located had been affected prior to 1951. Of the species found less frequently on these old dieback sites, 64% had not previously been associated with P. cinnamomi infection. Some of these were assessed for their susceptibility in glasshouse pathogenicity tests. New records of susceptibility were made at the species, genus and family levels. Several species regarded as being highly susceptible to infection by P. cinnamomi were found as frequently on old dieback sites as in unaffected vegetation. Many of the species found more frequently on dieback sites were probably present at the time of the initial dieback event. Others, mostly annuals, may have been introduced from nearby vegetation types with open canopies, such as granite outcrops. If plant invasions have occurred following dieback, the small differences in species richness between dieback and unaffected vegetation may hide a great reduction in species richness due to dieback. Structural changes following dieback may have a profound effect on some species regardless of their susceptibility to infection. A spatial association with trees on dieback sites was demonstrated for a range of species. The apparent reliance of some understorey species on tree cover is discussed in relation to current theories of patch dynamics. Two methods were used to isolate P. cinnamomi from dieback sites. In situ Banksia grandis baits were more effective at detecting P. cinnamomi than ex situ baited soils, especially when P. cinnamomi was apparently rare. P. cinnamomi was frequently isolated from creek edges with a long history of dieback and from active dieback fronts but was rarely found on sloping dieback sites affected prior to 1980. It is not clear if the P. cinnamomi present on pre-1951 dieback sites has persisted there since the initial dieback event or been re-introduced from active dieback fronts upslope. Very few highly susceptible species appear to be totally eliminated by the pathogen at the time of the initial dieback event. The mass deaths at that time are followed by a period of recolonization of susceptible species with highly germinable seed. The survival of the new cohort of these species is a function of the time taken to produce another crop of seed. Susceptible species may persist on the pre-1951 dieback sites because of highly germinable seed, young reproductive age, copious seed production and animal dispersal. The rarity of P. cinnamomi on these sites must greatly contribute to their persistence. Pathogenicity testing in excised stems indicated that resistance to the movement of P. cinnamomi in plant tissue develops in jarrah populations on many dieback sites, although it is unlikely to be integral to regeneration. Evidence of resistance in other species investigated could not be found. The key elements in the model of vegetation change developed in the thesis are (i) the on-going occurrence of P. cimiamomi on dieback sites, (ii) the susceptibility of plant species to infection by P. cimiamomi, (iii) the sensitivity of plant species to structural changes, (iv) the proportion of a plant population killed, (v) the capacity of plant species for rapid recruitment after dieback, (vi) the time taken for plant species from germination to reproduction, and (vii) the capacity of plant species to invade. Stochastic factors such as fire, logging, climatic perturbations, and diseases caused by other pathogens, cannot be quantified and easily incorporated into the model. Predictions are made about the future vegetation of dieback sites, contingent on intervention by forest managers. An epidemic - recovery cycle, involving concomitant fluctuations in pathogen and host populations, has been hypothesized by some authors for sites affected by P. cimiamomi. There is evidence of such a cycle on a small scale. On a larger scale, epidemics on dieback sites in the jarrah forest may be isolated in space and time. The importance of long-term ecological studies of jarrah forest vegetation to our understanding of natural forest processes and the effects of dieback is stressed

Progress in the recovery of the flora of treeless subalpine vegetation in Kosciuszko National Park after the 2003 fires

The fires of January 2003 burnt much of the treeless high mountain country of Victoria, New South Wales and the Australian Capital Territory, and were the first extensive conflagration of this area since 1939. For this reason there are remarkably few studies of the response of alpine plants and vegetation to fire. A flora survey of treeless subalpine vegetation in the Kosciuszko area in late 2002 sampled 215 sites. Of the 119 sites that were burnt, 60 were relocated and re-sampled in late 2003 to assess the mode and extent of regeneration in a range of treeless plant communities. Twenty-four species (including 3 exotics) were recorded only in the pre-fire sampling. Fifty species (including 18 exotics) were recorded only in the post-fire sampling. One species, Chenopodium erosum, had not previously been recorded in Kosciuszko National Park, and is believed to be the first native chenopod recorded in alpine vegetation in Australia. There was no significant difference in mean number of species per quadrat between pre-fire and post-fire quadrats. The average number of weeds per quadrat was, however, significantly greater post-fire. Most of this difference was attributable to the significantly greater number of weeds per quadrat in bog vegetation after the fire. Of the 290 species recorded, 111 species regenerated from seed, 197 species regenerated from resprouting organs (roots, tubers and/or basal stems) and 49 species regenerated from both seed and resprouts. Based on the regeneration observed, most plant communities will return naturally to their pre-fire species composition and cover over a period between a few years and a few decades. Major exceptions will be those communities where the ‘keystone’ species appear to have been lost at least at a local scale. Principal amongst these are bog communities that incorporated significant biomass of Sphagnum cristatum pre-fire, Podocarpus lawrencei shrublands and Celmisia costiniana closed herbfields. Consideration might be given to augmenting their recovery. It will be important to exclude fire from these communities until their recovery is complete

Quantifying the distribution and threat of Phytophthora cinnamomi in New South Wales: implications for its management in natural vegetation

Phytophthora cinnamomi is an oomycete (water mould) with a large host range. It infects plants through their roots and in some cases will kill them. The pathogen is readily dispersed in soil and water, over short distances by its swimming spores and over large distances by humans. While Phytophthora cinnamomi has been well-studied in other parts of Australia, its distribution and impact are poorly known in New South Wales (NSW). In the current study we compiled existing data on Phytophthora cinnamomi occurrence and filled spatial gaps in sampling. We found about 1000 records of Phytophthora cinnamomi presence in over 5000 tests of soil and root material, and collected a further 457 samples from areas where no sampling had previously been done. The resulting data set enabled modelling of Phytophthora cinnamomi habitat suitability using the software program MaxEnt with climate and soil spatial layers. We found that coastal areas and adjacent tablelands were most suitable for the pathogen, although some areas within that may be unsuitable because of soil properties. We then modelled assets (threatened species) potentially affected by Phytophthora cinnamomi to produce a layer of risk. Using projected climate layers, we found that habitat suitability and risk will decline in parts of northern NSW by 2070 but be amplified in the south. New susceptible species in places such as the Australian Alps are likely to be exposed to the pathogen in the future. We offer advice for managing Phytophthora cinnamomi in NSW. Management is difficult where the effects of this pathogen are often inconspicuous and its distribution is widespread. However, basic hygiene to limit spread to susceptible assets will have great benefit regardless

The flora of Nungar Plain, a treeless sub-alpine frost hollow in Kosciuszko National Park

Nungar Plain is a large, naturally treeless area in the northern part of Kosciuszko National Park. Abrief survey of the flora of Nungar Plain (December 2001–January 2002) recorded 206 taxa, 18 of which were introduced. Seven taxa appear to be of especial significance. The great floral diversity of Nungar Plain suggests that the botanical significance of sub-alpine plains in Kosciuszko National Park has been under-estimated. The flora and vegetation of Nungar Plain are threatened by pigs, which have scoured large areas of grassland vegetation. In six pairs of quadrats across disturbance boundaries, damage by pigs was found to have greatly reduced the cover and diversity of vegetation. Control of pigs is urgently required