Fire regimes affect survival and reproduction of shrub species in fire-prone vegetation such as occurs in Gibraltar Range National Park. The influence of fire regimes on resprouting shrubs is known for a range of species in coastal regions of Australia but is poorly known in montane sclerophyll communities. The fire responses of three Proteaceae shrubs ('Banksia spinulosa', 'Hakea laevipes', 'Petrophile canescens') and a grasstree ('Xanthorrhoea johnsonii') were measured after the wildfire of 2002 to determine whether: 1) storage organ size was related to post-fire growth and flowering response, 2) fire frequency influences postfire mortality and if survival was related to the size of plant; 3) fire frequency influences the resprouting ability of plants, and 4) fire frequency affects pyrogenic flowering in the post-fire environment. We found the size of storage organs was positively related to post-fire sprouting in the three shrubs and to flowering in the grasstree. However, high fire frequency only affected the survival of Banksia spinulosa and decreased flowering in 'Xanthorrhoea johnsonii'. Survival in all species ranged between 83 and 99% and it appears that the intervals between fires (7-22 years) had been sufficient for most adult plants to regain the ability to resprout. The ability of juvenile plants to develop the ability to resprout needs to be tested on seedlings that established after recent fires.

On the New England Tablelands wet sclerophyll forests typically form the ecotone between rainforest and dry sclerophyll forest. Currently there are few data on the response of wet sclerophyll plant species to fire. We compared the fire-response traits of woody understorey and sub-canopy species in wet sclerophyll forest after high and low intensity fires. The majority of species (>80%) resprouted after fire and the prevalence of resprouting did not differ with fire intensity. Obligate seeders were rare in these communities (<10% of species), and similar numbers of rainforest and sclerophyllous species were killed by fire. Resprouting from basal stems and root suckering were the most common mechanisms of vegetative regeneration; however, these traits may have arisen more in response to canopy disturbance than fire regime. We found that most rainforest taxa resprouted but lacked post-fire seedling recruitment, whereas most resprouting sclerophyllous taxa recruited from seed after fire. This dichotomy in seedling recruitment could reflect the productivity and disturbance gradients across the ecotone. We propose that gap-phase recruitment is favoured towards the rainforest margin and fire-related recruitment is more prevalent at the eucalypt forest edge.

Four 'Eleocharis' species exhibit habitat partitioning in both extant vegetation and in the soil seed bank of upland temporary wetlands on the Northern Tablelands of New South Wales. Explanations for this partitioning were sought in seed-bank dynamics at three shore levels in two wetlands. Habitat partitioning (zonation) was explained in part by seedling recruitment but not by either persistence of seeds in the soil or by dormancy patterns. All four species recruited at wetland edges but only the deepwater species, 'Eleocharis sphacelata', recruited in deeper water. Viability of buried seeds was consistently high and species had very low decay rates and half-lives greater than 50 years. Two types of dormancy patterns with burial were shown. Most seeds of 'Eleocharis sphacelata' and 'E. pusilla' were non-dormant after a 3-month burial, whereas for 'E. acuta' and 'E. dietrichiana' seed germination percentages gradually increased over a number of years. These two dormancy patterns may contribute to coexistence, since coexistence is enhanced by a long-lived resistant phase in the life history of species and by temporal variability in germination. There were also spatial inconsistencies in patterns of dormant fractions. Burial in the deeper zones of the marsh-like Billybung Lagoon had an inhibitory effect both on germinability and on germination rates of 'E. acuta' and 'E. dietrichiana' seeds. All but 'E. acuta' showed some degree of seasonal dormancy, but this pattern was also not consistent in space. Explanations for zonation should concentrate on other life-history phases, such as dispersal and seedling survival.

Questions: This paper examines the long-term change in the herbaceous layer of semi-arid vegetation since grazing ceased. We asked whether (1) there were differences in the temporal trends of abundance among growth forms of plants; (2) season of rainfall affected the growth form response; (3) the presence of an invasive species influenced the abundance and species richness of native plants relative to non-invaded plots, and (4) abundance of native plants and/or species richness was related to the time it took for an invasive species to invade a plot. Location: Alice Springs, Central Australia. Methods: Long-term changes in the semi-arid vegetation of Central Australia were measured over 28 years (1976- 2004) to partition the effects of rainfall and an invasive perennial grass. The relative abundance (biomass) of all species was assessed 25 times in each of 24 plots (8 m x 1 m) across two sites that traversed floodplains and adjacent foot slopes. Photo-points, starting in 1972, were also used to provide a broader overview of a landscape that had been intensively grazed by cattle and rabbits prior to the 1970s. Species' abundance data were amalgamated into growth forms to examine their relationship with environmental variation in space and time. Environmental variables included season and amount of rainfall, fire history, soil variability and the colonization of the plots by the exotic perennial grass 'Cenchrus ciliaris' (Buffel grass). Results: Constrained ordination showed that season of rainfall and landscape variables relating to soil depth strongly influenced vegetation composition when 'Cenchrus' was used as a covariate. When 'Cenchrus' was included in constrained ordination, it was strongly related to the decline of all native growth forms over time. Univariate comparisons of non-invaded vs impacted plots over time revealed unequivocal evidence that 'Cenchrus' had caused the decline of all native growth form groups and species richness. They also revealed a contrasting response of native plants to season of rainfall, with a strong response of native grasses to summer rainfall and forbs to winter rainfall. In the presence of 'Cenchrus' these responses were strongly attenuated. Discussion: Pronounced changes in the composition of vegetation were interpreted as a response to removal of grazing pressure, fluctuations in rainfall and, most importantly, invasion of an exotic grass. Declines in herbaceous species abundance and richness in the presence of 'Cenchrus' appear to be directly related to competition for resources. Indirect effects may also be causing the declines of some woody species from changed fire regimes as a result of increased fuel loads. We predict that 'Cenchrus' will begin to alter landscape level processes as a result of the direct and indirect effects of 'Cenchrus' on the demography of native plants when there is a switch from resource limited (rainfall) establishment of native plants to seed limited recruitment.

Rock outcrops are landscape features that may form habitat islands in a matrix of more widespread vegetation. The patterns of floristics, reproduction, gender, life span, growth forms, and fire response traits were compared between rock outcrops and matrix sclerophyll vegetation to test for insularity in taxon composition and functional traits. The outcrops and matrix had similar reproduction, gender, life span, and growth form traits, being dominated by co-sexual sclerophyll shrubs. The outcrops, however, were dissimilar in species composition and functional traits forming an archipelago of habitat islands in a forest matrix. Rank abundance curves were less even on rock outcrops than in adjacent forests, being dominated by shrubs that were killed by fire (obligate seeders). The ratio of shrubs killed by fire (obligate seeders) to resprouters was 70:30 on the outcrops compared with 38:62 in the matrix. Evidence for functional convergence in fire response traits comes from 27 genera, in 17 families, which have congeners in each habitat. Most shrub congeners on or near rocky outcrops were killed by fire whereas related taxa in the forests resprout after fire. Functional convergence can be related to disturbance frequency and/or differences in regeneration niche among habitats. A resprouting response appears to be related to more frequent fires in the matrix as outcrops experience fires less often. The dominance of obligate seeding shrubs on high rainfall outcrops may also be related to better resources in an environment where allocation to growth rather than storage could be advantageous. In drier and shadier habitats, however, resprouting may be promoted over seedling recruitment as the risks of recruitment failure are higher.

Aim, Location:Landscape features, such as rock outcrops and ravines, can act as habitat islands in fire-prone vegetation by influencing the fire regime. In coastal and sub-coastal areas of Australia, rock outcrops and pavements form potential habitat islands in a matrix of fire-prone eucalypt forests. The aim of this study was to compare floristic composition and fire response traits of plants occurring on rocky areas and contrast them with the surrounding matrix.Methods:Patterns of plant community composition and fire response were compared between rocky areas and surrounding sclerophyll forests in a range of climate types to test for differences. Classification and ordination were used to compare floristic composition and univariate analyses were used to compare fire response traits.Results:The rock outcrops and pavements were dissimilar in species composition from the forest matrix but shared genera and families with the matrix. Outcrops and pavements were dominated by scleromorphic shrubs that were mainly killed by fire and had post-fire seedling recruitment (obligate seeders). In contrast, the most abundant species in the adjacent forest matrix were species that sprout after fire (sprouters).Main conclusions:Fire frequency and intensity are likely to be less on outcrops than in the forest matrix because the physical barrier of rock edges disrupts fires. Under the regime of more frequent fires, obligate seeders have been removed or reduced in abundance from the forest matrix. This process may have also operated over evolutionary time-scales and resulted in convergence towards obligate seeding traits on outcrop fire shadows. In contrast, there may have been convergence towards sprouting in the forest matrix as a result of selection for persistence under a regime of frequent fire.

Papers on the biology and ecology of Gibraltar Range National Park were sought to reflect the increased research focus on the area over the past decade. The 12 papers, published here, come from a variety of natural history disciplines. This collection of papers reflects the start that has been made, and, hopefully, will stimulate further biological and ecological investigation of Gibraltar Range National Park. Gibraltar Range National Park was first dedicated in the 1960s following the construction of the Gwydir Highway connecting Glen Innes and Grafton in northern NSW. Prior to this the area had been used for grazing, prospecting, forestry and had been surveyed for the potential use of hydroelectricity. However, it remained little explored in terms of its biology and ecology until the 1960s and 70s when John B. Williams began to collate species lists and describe the broad patterns of vegetation (Williams 1970, 1976).

Fire is an important ecological factor that influences the distribution and abundance of plant populations of shrub species in fire-prone habitats. Comprehensive information about the fire-response syndromes and post-fire recruitment of seedlings in tableland habitats of eastern Australia is poorly known. In particular, data on shrubs occurring in grassy habitats are lacking for temperate regions of Australia. The post-fire response and recruitment patterns of shrub taxa were recorded from research burns and wildfires on the New England Tablelands over 4 years in the following four habitats: grassy woodlands and open forests, shrubby open forests, wet heaths and rocky outcrops. The ratio of obligate seeder to resprouter species differed among habitats, with the highest ratio occurring on rocky outcrops (90 : 10) and the lowest in grassy forests (19 : 81). Post-fire recruitment of seedlings was also highest on rocky outcrops whereas seedlings were rarely observed in the wet heaths and grassy forests. The following six models that explain these patterns were reviewed: fire and grazing frequency, soil nutrients and texture, habitat openness and environmental variability. No one model could uniformly explain differences in fire response across all habitats but a combination of disturbance-frequency and regeneration-niche models may provide a mechanism for the patterns observed. Field and laboratory experiments are needed to examine allocation to persistence (resprouting) and reproduction in species with different fire-response syndromes. These experiments also need to examine both disturbance-frequency and regeneration-niche factors in manipulative experiments.

Propagule (diaspore) predation by crabs has been shown to be a major source of mortality for mangroves. We measured predation by crabs on seeds of nine tropical mangrove species in multifactorial experiments by following the fates of tethered propagules.We tested whether planting, intertidal position and canopy gaps influenced predation of propagules and whether the predation of propagules was reduced in the presence of conspecifics. We also tested if predation influenced patterns of propagule establishment.Mortality due to predation ranged from 22 to 100%, with Aegiceras corniculatum > Avicennia marina > Bruguiera parviflora > Aegialitis annulata > B. exaristata > Ceriops australis > C. decandra=B. gymnorrhiza > Rhizophora stylosa. Initial predator preference was correlated with the size of propagules.Propagule planting (prone vs. implanted) and canopy type had the largest magnitude of effects across all species for treatment effects. Propagules dispersed in the prone position had more mortality while those dispersed into canopy gaps were generally less preyed upon. Three species were tested for dominance-predation by regression of stand relative density with final predation by crabs for canopy treatments. No species had significant effects that supported the hypothesis.Predation by crabs often changed with intertidal position but showed no consistent pattern among species or gap treatments. Interactions of canopy treatment and tidal position showed that predation by crabs did not have a major influence on the zonation of mangroves in our study sites.Analyses of covariance of predation and establishment showed that establishment success is strongly controlled by predation in six of the nine species tested. This suggests that herbivores have a greater impact on recruitment than do microhabitat effects on resources. The combined effects of predator refuge and growth preference enhance recruitment in large canopy gaps. Crab predators appear to maintain the floristic similarity between canopy gaps and surrounding forests in tropical mangrove forests of northern Australia by removing allopatric species from gaps.

High rainfall escarpment areas along the Great Dividing Range provide habitats for sedgeland and wet heath vegetation in areas with impeded drainage. There are few studies of the processes that influence the floristic composition of montane sedgelands and heaths in relation to fires that sweep these landscapes. Gibraltar Range National Park contains extensive areas of sedge-heaths that remain mostly free from anthropogenic disturbance. These areas have a well-known fire history which provides an opportunity to test whether: 1) plant resources are related to time-since-fire; 2) floristic composition is more strongly related to physiographic factors than time-since-fire, and 3) floristic composition of vegetation is related to fire frequency. Physiographic position strongly influenced the vegetation's structure and floristic composition, with taller heaths confined to better-drained edges whereas sedgelands were more common in poorly drained slopes regardless of fire regime. In turn, these patterns were related to soil conductivity reflecting the fertility status of the soils. Upper slope heaths were more species rich than those lower in the landscape where soil conductivity was higher. Time-since-fire strongly influenced heath structure and species richness declined in the heaths with canopy closure at some sites. Floristic composition across the physiographic gradient was more divergent soon after fire and became more similar 15 years after fire. Fire frequency had no significant effect on shrub species richness, but frequent fires decreased the abundance of some woody species. Inter-fire intervals of less than seven years may reduce the abundance of some shrub species. Both the history of fire and ease of access make the sedgelands and wet heaths of Gibraltar Range an ideal location to assess the long-term effects of fire regimes in montane sedge-heaths.