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Coastal freshwater wetlands (CFWs) are among the most understudied wetlands globally and are highly vulnerable to projected climate changes. To address CFW knowledge gaps in south-east Queensland, Australia, we surveyed the floristic composition and structure of wooded CFWs and explored variation in vegetation patterns in relation to selected environmental drivers. Understorey and shrub assemblages were surveyed using a cover-class scale and stem counts for tree species abundance. Vegetation structure attributes (stem density, basal area) were calculated from survey data. Redundancy analysis was used to investigate drivers of vegetation structure and the species composition of each stratum. Vegetation structure patterns were associated with gradients of rainfall, soil moisture, salinity and pH. Understorey species composition was associated with wallum wetland species, native perennial grass and herb species, and vegetation patterns of the canopy. Common CFW species, namely Melaleuca quinquenervia and Eucalyptus tereticornis, dominated tree assemblage variation. Overall, CFW vegetation exhibited strong associations with gradients of salinity, rainfall, groundwater dependence and disturbance. Alterations to key drivers of vegetation pattern with future climate changes are likely to markedly influence the composition, structure and function of CFW vegetation communities. Action is therefore required to maintain CFW vegetation communities and ecological function in these diverse and unique wetland systems.

Forest fires are important natural disturbances that influence accurate estimations of forest carbon budgets, largely owing to the uncertainty of carbon emissions from forest fires. Fuel burning efficiency is an important factor affecting accurate estimations of carbon emissions and is difficult to quantify. Here, we quantified burning efficiencies of fuel strata by fire severity and forest types and investigated influencing factors. Burning efficiencies of fuel strata increased with increasing fire severity. The tree stratum had low values of burning efficiency of 0.76, 0.83, 6.84% under low-, moderate-, high-severity fires respectively. The burning efficiency of the herb stratum was the highest, over 95%, followed by the litter stratum between 49 and 85%. Although the tree stratum accounted for the largest carbon storage of aboveground fuels, most carbon consumed during fires came from the shrub and herb strata. Among forest types, the burning efficiency of aboveground fuels in Pinus pumila–Larix gmelinii forest was much higher than the other two studied. Fire Weather Index (FWI) and temperature exerted a positive effect on the burning efficiency of understorey fuels. Precipitation mainly had a negative influence on the burning efficiency of shrub and duff.

Forest fire severity influences post-fire fuel structure and thus the behaviour of subsequent fires. Understanding such interactions is critical to improving predictions of fire risk and emergency management, yet few studies have quantified fire severity effects on fuel attributes. We quantify fuel structure of a fire-tolerant eucalypt forest 7 years after a landscape-scale wildfire in south-eastern Australia. We used high-density airborne lidar data to estimate understorey fuel metrics in three strata representing horizontal and vertical connectivity in 1084 plots (0.06 ha) representing four wildfire severities (unburnt, low, moderate, high). Fuel structure was changed by high-severity fire, which significantly increased the cover and horizontal connectivity of the elevated and midstorey strata and decreased space between the understorey and canopy relative to other severity types. Random Forest models indicated that understorey fuel metrics were most influenced by wildfire severity, pre-fire values of each metric, and post-fire canopy cover, and least influenced by climatic and topographic variables. Our study provides evidence of positive feedbacks to flammability by high-severity wildfire in fire-tolerant eucalypt forests through increased horizontal and vertical fuel connectivity. It demonstrates the utility of airborne lidar data for quantifying fuel structure in complex forests and providing critical data for fire risk assessments.

The expansion of rainforest trees into long-unburnt open forests is widespread globally, including in high-rainfall regions of eastern Australia. Increased tree density can reduce insectivorous bat activity and species richness by constraining echolocation and foraging success. Yet it is unknown whether sclerophyll and rainforest trees differ in their effects on open forest bat communities. We sampled insectivorous bats and nocturnal flying insects at two heights (understorey, canopy) in dry sclerophyll forest of eastern Australia with contrasting fire histories and levels of rainforest pioneer invasion. We found that both time since fire and functional identity of midstorey trees influenced the local bat community, whereas insect biomass had little effect. Long-unburnt forests with a rainforest pioneer midstorey had lower bat activity (63% lower) and species richness (35% lower) than recently burnt forests with a more open midstorey. Bat species richness also declined beneath the dense sclerophyll midstorey in long-unburnt forests, although was unaffected in the canopy above. Strong negative correlations between rainforest tree density and bat community activity and richness indicate that rainforest trees, in contrast with sclerophyll trees, exert additional negative control over open forest bat communities. Our results show that habitat suitability for clutter-intolerant bats declined well before the often-recommended maximum fire-intervals for dry open forest, providing evidence of an upper threshold for fauna conservation in rainforest-invaded open forests. To conserve bat communities in dry open forests vulnerable to rainforest invasion, fire should occur with sufficient frequency to prevent rainforest pioneers developing a dense midstorey that displaces clutter-intolerant bats.

The southern hairy-nosed wombat has a fragmented distribution across the arid and semiarid regions of southern South Australia and south-eastern Western Australia. Its distribution and abundance are highly patchy, with large clusters of warrens in some areas but few to no warrens in adjacent areas. In order to understand why this occurs, we mapped the species’ distribution and correlated the locations of over 8130 data points (5349 presence points and 2781 absence points) with environmental and landscape data. Overall, the wombat distribution is influenced by rainfall, with no wombats in areas where the mean annual rainfall is 227mm per annum. At the regional/local scale, warrens are found only in areas where the soil clay content is between 9 and 40%, and warren abundance is higher in open vegetation classes (saltbush/bluebush shrublands, grasslands) than in closed vegetation (mallee woodlands with shrubby understorey). Over-riding all of these environmental influences are anthropogenic land-use practices: although 38% of the wombats are located in protected areas and 51% are located on grazing land, they are virtually absent from croplands (~2%).

Prescribed burning is a common land management tool used to reduce fuels, emulate the effects of wildfire and increase heterogeneity in fire-prone ecosystems. However, the forest structure created by prescribed burning is likely to be dissimilar to that produced by wildfire. We used three-dimensional estimates of canopy bulk density (CBD) from lidar data to explore the relationship between fire type, number of burns and fuel structure/forest structure in the New Jersey Pinelands National Preserve, USA. We found that in areas of previous prescribed fires, as the number of fires increased, the understorey (1–2m) exhibited a slight decrease in CBD, while the upper canopy (15–23m) had higher values of CBD for ≥4 fires, though these differences were not statistically significant. However, an increasing number of wildfires was associated with a statistically significant increase in CBD in the mid-storey (3–7m) and a decrease in CBD in the canopy (≥8m). These results have important implications for forest resource managers because they indicate that prescribed burning reduces ladder fuels that lead to torching and crown fires, but it does not replicate the structure created by wildfire.

The bell miner (Manorina melanophrys) is a despotic honeyeater. Little is known about permanent colonisation in this species. Our banding study aimed to document changes in species richness over time and capture the effect of a despotic species. Our study is the first to document individual movements that led to the establishment of two permanent breeding colonies over 22 years of banding. One site in the Australian Botanic Garden, Mount Annan where birds moved in, compared to Camden Airport where bell miners have been present since the mid-1950s. Over the first 12 years there were three short-term visits by small groups of bell miners into the Conservation Woodland Area, in the Australian Botanic Garden, Mount Annan, for a maximum of three months. Retrapping of individuals showed that birds were first-year and older and travelled 2.1–4.2km. In 2016, both colonies contained over 120 birds and species richness changed, particularly of canopy-foraging species. At the Australian Botanic Garden, Mount Annan, 18 bird species decreased in number, with three no longer present (F33,34=2.50, P=0.00). Two other species also colonised the area and 13 increased in number. Understorey species such as the satin bowerbird, the eastern spinebill and the superb fairy-wren increased significantly. Movements of 0.3–1.0km were also detected at the Camden Airport site. At Camden Airport, five species decreased in number and four species increased but species richness stayed the same. Interestingly, bell miners decreased in number. After a heat wave in Summer 2016/17, bell miner weights declined and the colony disappeared. No eucalypt defoliation was observed in November 2017. Understorey modifications occurred only in areas away from the study sites during this project, suggesting that weather and food resources are the main contributing factors to colony establishment and longevity.

Seedling planting is the most common strategy used to reintroduce tropical native tree species; however, direct sowing has simplicity and operational ease advantages. Functional traits such as seed size and growth rates have been shown to be relevant for better plant performance. We evaluated the effects of intraspecific variation in seed size and the reintroduction strategy simultaneously on the development of Hymenaea courbaril (L.) and Enterolobium timbouva (Mart.) introduced in an abandoned eucalyptus plantation over 462 days. Plants from small, medium and large seeds were reintroduced by planting seedlings and direct seeding. Both species achieved high rates of emergence and survival was high in the two reintroduction strategies. Seed size was not related to emergence and mean time to emergence for either species. The survival of both species was higher than 74% in the field, and seed size had little effect on survival rates. In general, H. courbaril plants introduced by direct sowing had higher growth, and seed size correlated positively with stem size. In contrast, the growth of E. timbouva plants introduced by seedling planting was higher than in plants introduced by direct sowing regardless of seed size. The light requirements of this species seem higher than for H. courbaril. Our results suggest the feasibility of reintroducing species by direct sowing in eucalyptus understory, but since plant growth varies between species, there may be a balance between the advantage of the initial plant size provided by planting seedlings and the advantage of a better root development provided by direct sowing.

Forest canopy loss due to plant pathogens, insect or abiotic factors significantly alters habitat and resource availability for animals, which has flow-on effects for whole ecosystems. The tuart (Eucalyptus gomphocephala) has been in decline throughout its geographic range; this is likely associated with watertable and salinity changes, although a plant pathogen (Phytophthora multivora) has also been implicated. We examined the relative abundance of common brushtail possums (Trichosurus vulpecula) across 12 sites (each 0.72 ha) selected on the basis of the health of dominant tuart trees (six ‘healthy’ and six ‘declining’ sites). Habitat variables (understorey, tuart dimensions and density, tree hollows, tree-to-trap distance) and tuart tree health (crown loss, epicormic regrowth) were compared with possum abundance. Possums were detected at most sites. There was no significant difference between brushtail possum numbers at ‘healthy’ or ‘declining’ sites, although marginally more possums were recorded at declining sites (5.7 ± 1.5 (s.e.), n = 6 sites) compared with healthy sites (3.3 ± 0.7; Cohen’s effect size d = 0.80). Slightly higher abundance of possums was associated with sites that had a greater density of smaller-diameter but taller tuart trees. ‘Declining’ sites, with more epicormic regrowth and greater tree densities, may provide more palatable food resources for possums.

When flammable plant species become dominant they can influence the flammability of the entire vegetation community. Therefore, it is important to understand the environmental factors affecting the abundance of such species. These factors can include disturbances such as fire, which can promote the dominance of flammable grasses causing a positive feedback of flammability (grass–fire cycle). We examined the potential factors influencing the abundance of a flammable grass found in the understoreys of forests in south-east Australia, the forest wiregrass (Tetrarrhena juncea R.Br.). When wiregrass is abundant, its structural characteristics can increase the risk of wildfire ignition and causes fire to burn more intensely. We measured the cover of wiregrass in 126 sites in mountain ash forests in Victoria, Australia. Generalised additive models were developed to predict cover using climatic and site factors. The best models were selected using an information theoretic approach. The statistically significant factors associated with wiregrass cover were annual precipitation, canopy cover, disturbance type, net solar radiation, precipitation seasonality and time since disturbance. Canopy cover and net solar radiation were the top contributors in explaining wiregrass cover variability. Wiregrass cover was predicted to be high in recently disturbed areas where canopy cover was sparse, light levels high and precipitation low. Our findings suggest that in areas with wiregrass, disturbances such as fire that reduce canopy cover can promote wiregrass dominance, which may, in turn, increase forest flammability.

Bell miner–associated dieback (BMAD) is a form of canopy decline involving bell miner (Manorina melanophrys) colonies on the eastern coast of Australia. The association can include an understorey of lantana (Lantana camara) preventing eucalypt regeneration. To date, comparatively little is known about the effects of these processes on mammal diversity and abundance. We therefore considered the effects of BMAD and lantana presence on ground mammals and insectivorous bats in four forest sites within New South Wales. These were monitored in association with a restoration project for the treatment of lantana that used glyphosate spraying to kill lantana in half of six 50m×50m quadrats per site (three control and three treated). Passive bioacoustic recorders, infrared cameras and Elliott traps were used to survey understorey fauna over four consecutive nights during each season. We found a greater number of small ground-dwelling and large mammals in control areas with an intact understorey of lantana relative to areas where lantana had been treated. However, insectivorous bats were not influenced by lantana presence. Our results suggest that ground-dwelling mammals benefit from the presence of lantana, as it may provide structural complexity that reduces predation risk and/or provides a food resource.

A salvage translocation of western brush wallabies (Notamacropus irma (Jourdan, 1837)) was a condition of approval to build a new runway at Jandakot Airport, Western Australia. Since little is known about this endemic Western Australian species, the translocation presented a valuable opportunity to gain information on the species after release into Harry Waring Marsupial Reserve, a 260-ha reserve where these animals had been recorded previously. We aimed to gain information on the biology and ecology of the species and follow the movement of individuals tracked with Global Positioning System (GPS) collars over six months to determine their short-term survival, home-range establishment, overlap in home range between individuals, and habitat utilisation in the reserve. Weekly mean home-range estimates did not differ between males (10.0±9.7 (s.d.) ha, 95% KDE, n=6) and females (12.1±6.1 (s.d.) ha, 95% KDE, n=5) (P=0.473). Some males had 67–70% overlap in home ranges with some females, but substantial distances maintained between individuals (from 123±110m to 292±303m) confirmed the solitary nature of the species. Western brush wallabies preferred Banksia spp. woodlands, possibly due to the availability of canopy cover, and some specific understorey associations, such as Hibbertia hypericoides, that form part of their diet. Our study highlighted the importance of understanding the home-range establishment and vegetation preferences of translocated animals that will inform the planning of future translocations.

Forest restoration treatments seek to increase resilience to wildfire and a changing climate while avoiding negative impacts to the ecosystem. The extent and intensity of treatments are often constrained by operational considerations and concerns over uncertainty in the trade-offs of addressing different management goals. The recent (2012–15) extreme drought in California, USA, resulted in widespread tree mortality, particularly in the southern Sierra Nevada, and provided an opportunity to assess the effects of restoration treatments on forest resilience to drought. We assessed changes in mixed-conifer forest structure following thinning and understorey burning at the Kings River Experimental Watersheds in the southern Sierra Nevada, and how treatments, topography and forest structure related to tree mortality in the recent drought. Treatments had negligible effect on basal area, tree density and canopy cover. Following the recent drought, average basal area mortality within the watersheds ranged from 5 to 26% across riparian areas and 12 to 44% across upland areas, with a range of 0 to 95% across all plots. Tree mortality was not significantly influenced by restoration treatments or topography. Our results suggest that the constraints common to many restoration treatments may limit their ability to mitigate the impacts of severe drought.

The Mill Fire, which burned in north-western California during the summer of 2012, provided a unique research opportunity when firefighters implemented a backfiring operation to limit wildfire growth. This backfire was ignited and burned through research plots from a long-term study designed to determine the effects of tree density manipulation and shrub control on the growth and stand development of a ponderosa pine plantation. The objectives of this study were to examine the response of these 53-year-old trees to the backfire and to determine how the fire effects differed with plantation structure and composition. Measurements made 4 years post-fire showed that mortality rate was highly variable (from 0 to 100%) and did not relate to tree density, height of live crown, total basal area or shrub cover. Bole char height explained 65% of the variation in mortality rate. Fire appeared to spread primarily through the surface litter and killed a substantial proportion of the shrubs competing with the trees for water and nutrients. Importantly, post-fire tree growth was not significantly affected relative to pre-fire growth. A lack of negative effects of the fire on radial growth was possibly a result of release from inter-tree and shrub competition, which balanced any declines that might have been expected from bole injury or crown loss. Results from the present study demonstrate that ponderosa pine plantations could potentially be treated with managed fire (e.g. prescribed fire) without pretreatment (i.e. thinning, mastication), and still achieve good survival and improved resilience to wildfires burning under uncontrolled conditions.

The reestablishment of natural fire regimes may benefit forest ecosystems by restoring their fundamental structural, compositional or functional attributes. We examined the influence of fire on the structure, understorey diversity and health of red fir (Abies magnifica) forests by comparing burned and unburned stands in 22 separate, paired fires of Yosemite, Sequoia and Kings Canyon National Parks and the Giant Sequoia National Monument. Burned red fir plots were characterised by lower tree densities and canopy cover, restored spatial heterogeneity and higher understorey species richness than unburned plots. Densities of large trees and large snags and red fir regeneration were similar between burned and unburned sites. Forest health indicators were similar between burned and unburned sites, and red fir crown loss ratings were primarily associated with topographic variables indicative of increased moisture stress or reduced soil moisture availability (i.e. lower elevations, south-facing slopes). Our results suggest that fire does not improve the health of red fir trees especially in areas of greater moisture stress, but it can restore red fir forest structure, increase understorey diversity and enhance adaptive capacity in landscapes with reestablished fire regimes.

Exploration for oil and gas resources requiring the clearing of seismic lines has been occurring in central and northern Australia for many years. For example, seismic surveys have been conducted in the West Kimberley region of Western Australia since the 1960s. Despite this being a widespread practice, the recovery of vegetation on seismic lines has not been well studied. To better understand vegetation recovery in the West Kimberley, we conducted vegetation surveys on recovering seismic lines cleared using a raised-blade technique, from ∼two months to 4.9 years post-clearing, and compared them to paired control plots. Generally, the vegetation structure and community composition on seismic lines recovered quickly, with no discernible difference between control and seismic plots that were cleared more than 6 months prior. Some individual vegetation characteristics (e.g. understorey density and overstorey cover) recovered slowly, whereas other characteristics such as the number of individual grasses, recovered quickly. Vegetation recovery was confounded by the time since fire, which accounted for differences in vegetation structure at 1–2 years and 3–4 years since clearing. The fast recovery rate observed suggests that raised-blade clearing may not present a lasting impact on Pindan vegetation in the West Kimberley.

Made available in DSpace on 2018-11-26T16:48:26Z (GMT). No. of bitstreams: 0 Previous issue date: 2016-01-01 Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) Savanna vegetation maintains its openness and its diverse plant composition because of frequent fire events; however, when these are suppressed, encroachment is caused by increases in the tree density. In the neotropical savanna (cerrado of Brazil), typical forest trees are invading savanna areas, altering abiotic conditions and affecting the persistence of their exclusive species. Here we studied changes in abiotic conditions, species richness and diversity of a non-arboreal community (herbs, vines, grasses, subshrubs and shrubs) in a gradient of encroachment at a site where fire has been suppressed for more than 50 years in south-eastern Brazil. Encroached communities were more shaded and possessed a wetter and richer soil (higher contents of organic matter and P) compared with the typical savanna. These abiotic changes were related to a less rich and less diverse plant community in encroached savanna compared with typical savanna. The most important abiotic variables driving such changes were photosynthetically active radiation (PAR) reaching the understorey and soil P content: communities with lower species richness and diversity had lower PAR incidence and higher soil P content. Our results suggest that non-arboreal savanna species may be under serious threat of extinction given the expected ecological changes caused by the widespread expansion of forest on the savannas in the absence of fire. Univ Estadual Paulista, Fac Ciencias & Letras, Dept Ciencias Biol, Campus Assis,Av Dom Antonio 2100,Parque Univ, BR-19806900 Assis, SP, Brazil Univ Estadual Paulista, Fac Ciencias Agr & Vet, Dept Biol, Campus Jaboticabal, BR-14884900 Jaboticabal, SP, Brazil Univ Estadual Paulista, Fac Ciencias & Letras, Dept Ciencias Biol, Campus Assis,Av Dom Antonio 2100,Parque Univ, BR-19806900 Assis, SP, Brazil Univ Estadual Paulista, Fac Ciencias Agr & Vet, Dept Biol, Campus Jaboticabal, BR-14884900 Jaboticabal, SP, Brazil FAPESP: 2013/18049-6 FAPESP: 2015/19771-2 CNPq: 301589/2015-1

The endangered Blue Mountains water skink (Eulamprus leuraensis), a habitat specialist known from approximately 60 threatened highland peat swamps, is the sole endemic vertebrate of the Blue Mountains region, Australia. We quantified the species’ habitat associations by surveying 10 such swamps annually for three years. We scored habitat features and trapped skinks, comparing habitat attributes of trap sites where skinks were and were not captured. The distribution of E. leuraensis was non-random: skinks were found at sites with high values for some variables (soil moisture, live vegetation, surface water, understorey density and numbers of burrows) and low values for others (dead vegetation, logs, rocks, bare ground, canopy cover, sunlight penetration and numbers of invertebrates), and were mostly found in sites that were close to surface water and far from trees and logs. Eulamprus leuraensis is widely distributed within swamps, with weak associations between microhabitat variation and skink presence. Skink abundance and mean body size were highest within swamp centres, decreasing towards the margins; larger skinks were found closer to water, gravid female skinks were found at wetter sites and juveniles occupied marginal habitat. Skinks were rarely recaptured >10 m from their original site, with adult males travelling further than adult females and juveniles. We developed a quick field detection method for managers to assess the likely presence of E. leuraensis using two habitat attributes (soil moisture and burrow abundance). We mapped the species’ known and predicted habitat using GIS spatial layers, including locality records, associated vegetation communities and digital elevation models.

Deep shade and waterlogging are two common stressors affecting seedling performance in the understorey of evergreen rainforests. It has been hypothesised that high levels of carbon storage confer shade- and waterlogging tolerances by preventing carbon limitation under such stresses. Whether the tolerance to both stresses is positively or negatively related remains unclear. To explore the role of carbon storage in the relationships of waterlogging and shade tolerance, we investigated the responses to waterlogging and the levels of carbon storage in two species pairs with contrasting shade tolerance: Embothrium coccineum J.R.Forst.&G.Forst. and Gevuina avellana Mol. (Proteaceae) and Nothofagus dombeyi (Mirb.) Oerst. and Nothofagus nitida (Phil.) Krasser (Nothofagaceae). We subjected seedlings to waterlogging or control conditions for 30 days and evaluated survival, relative growth rate (RGR), biomass distribution, leaf chlorophyll fluorescence (Fv/Fm), and concentrations of total soluble sugars, starch and non-structural carbohydrates in different plant tissues. Waterlogging reduced survival, Fv/Fm and RGR in all species; however, the magnitude of reduction of Fv/Fm and RGR was significantly higher in the shade-intolerant species than in their shade-tolerant counterparts. In general, shade-intolerant species had significantly higher non-structural carbohydrate concentrations in waterlogging than in control conditions. By contrast, shade-tolerant species had similar non-structural carbohydrate concentrations under both conditions. Our results indicate that relatively shade-tolerant species performed better under waterlogging. A reduction in non-structural carbohydrates under waterlogging was not observed in any of studied species; rather, shade-intolerant species exhibited non-structural carbohydrate accumulation suggesting that carbon storage does not confer waterlogging tolerance in these species.

Fuel hazard is often assumed to increase with fuel age, or the time-since-fire. However, studies on fuel hazard in long-unburned forests are scarce. We measured overall fuel hazard in Eucalyptus forests and woodlands in south-eastern Australia at 81 sites where time-since-fire spans 0.5 years to at least 96 years. Overall fuel hazard was higher in forests and woodlands burned 6–12 years previously than those unburned for at least 96 years. The probability of high, very high or extreme overall fuel hazard – which is an operational threshold considered to equate with almost no chance of wildfire suppression in severe fire-weather – was highest 0.5–12 years post-fire, and lowest where fire had not occurred for at least 96 years. Frequent burning can maintain forest understorey in an early successional ‘shrubby’ state, leading to higher overall fuel hazard than forests where a lack of fire is associated with the senescence of shrubs. Protecting long-unburned sites from fire and managing to transition a larger proportion of forest to a long-unburned state may benefit fuel-hazard management within these forests in the long-term.

Efforts to restore forests for ecological and economic benefit in Hawaii are converging on koa (Acacia koa), an endemic dominant or codominant canopy tree common across broad elevation and moisture gradients. We quantified plant species composition and forest structure in koa reforestation areas (KRAs) and in nearby intact native forest on Hawaii Island. Total species richness and percentage native species richness were lower in the plantation forests than in the intact forests, although species richness in the KRAs at one site was not significantly different from that in intact forest. Tree, sapling, and seedling densities differed between KRAs and forest sites at one site. At another, the native forest and one KRA had similar tree and seedling densities and similar canopy height and percentage canopy cover. Total stand basal area was greatest in the intact forest at both sites, although the basal area for the KRAs at one site exceeded those for intact forest at the other. Koa plantings can be structurally similar to intact forests though species composition differs. Our results suggest that koa forestry can facilitate native understorey development in some cases.

Intense fire is a key threatening process for the endangered Blue Mountains water skink, Eulamprus leuraensis. This species is restricted to isolated, densely vegetated and waterlogged peat swamps in montane south-eastern Australia. We surveyed 11 swamps (5 unburnt, 6 burnt) over 2 years, before and after the intense spring bushfires of 2013, to quantify the fires’ impacts on these skinks, other lizards and the habitat upon which they depend. Trapping revealed no direct effect of fire on E. leuraensis populations, with skinks persisting in all burnt swamps. Fire modified ground vegetation, virtually eliminating live plants and the dense understorey. Despite the conflagration, vegetation regrowth was rapid with swamp habitat largely recovering in just over 1 year post-fire. Fire thus had only a transitory effect on lizard habitat and a non-significant impact on E. leuraensis numbers. Nonetheless, broader-scale analyses suggest a different story: skinks were more abundant in swamps that had experienced a longer time since major fire. Although the ability of this endangered reptile to survive even intense wildfires is encouraging, fire during prolonged dry periods or an intensified fire regime might imperil skink populations.

Interpretations of post-fire condition and rates of vegetation recovery can influence management priorities, actions and perception of latent risks from landslides and floods. In this study, we used the Waldo Canyon fire (2012, Colorado Springs, Colorado, USA) as a case study to explore how a time series (2011–2016) of high-resolution images can be used to delineate burn extent and severity, as well as quantify post-fire vegetation recovery. We applied an object-based approach to map burn severity and vegetation recovery using Worldview-2, Worldview-3 and QuickBird-2 imagery. The burned area was classified as 51% high, 20% moderate and 29% low burn-severity. Across the burn extent, the shrub cover class showed a rapid recovery, resprouting vigorously within 1 year, whereas 4 years post-fire, areas previously dominated by conifers were divided approximately equally between being classified as dominated by quaking aspen saplings with herbaceous species in the understorey or minimally recovered. Relative to using a pixel-based Normalised Difference Vegetation Index (NDVI), our object-based approach showed higher rates of revegetation. High-resolution imagery can provide an effective means to monitor post-fire site conditions and complement more prevalent efforts with moderate- and coarse-resolution sensors.

We describe microhabitat use and response to disturbance by the eastern pygmy-possum (Cercartetus nanus) in heathy dry sclerophyll forest using spool-and-line-tracking. We compared unlogged forest with forest regenerating four years after selective logging. Structural and floristic attributes were scored along spool lines and compared with a random line for each possum. We found that possums (n = 23) selected areas based on both structural and floristic attributes. Possums selected dense understorey, especially that comprising flowering hairpin banksia (Banksia spinulosa) and Gymea lily (Doryanthes excelsa). Fallen logs were not selected by nocturnally active possums. Spool lines in regrowth forest had less eucalypt cover and more understorey cover (e.g. D. excelsa and B. spinulosa) than unlogged forest. Conversely, cover of Banksia serrata was less in regrowth than unlogged forest. Spool lines were commonly found both at ground level (mean = 52–57% of lengths) and above the ground (43–48% of lengths). There was no difference in the mean spool height between the logging treatments (regrowth: 0.47 ± 0.14 m; unlogged: 0.49 ± 0.10 m; ± s.e.). Overall, our results suggest that the dense, flowering understorey that regenerates after selective logging is suitable for use and is the primary attribute selected by active pygmy-possums.

Shrubs often form the understorey in Mediterranean oak woodlands. These shrubs are exposed to recurrent water deficits, but how they will respond to predicted future exacerbation of drought is not yet understood. The ecophysiology of the shrub Cistus salvifolius L. was studied over the summer of 2005, which was during a heat-wave superimposed on the most severe drought in the Iberian Peninsula in the last 140 years. Branch water potential fell drastically during the summer, accompanied by stomatal closure and downregulation of PSII, with a concomitant loss of chlorophyll in the leaves. A parallel increase in the ratio of light-dissipating to light-capturing pigments and the proportion of xanthophyll cycle pigments in the de-epoxidated state, along with alterations in the structure of the light harvesting complex, may have reduced the potential for damage to leaves. Substantial increases in leaf tocopherol content during high radiation may have reduced damage from free radicals. Following autumn rains, leaves of the same shrubs showed physiological recovery, indicating the resilience of this Mediterranean species, for which an extremely dry hydrological year with 45% less rainfall than average, did not prevent healthy leaf functioning in response to renewed soil moisture availability.

The stability and dynamics of multispecies interactions often rely on a small core of species. We examine whether the Yellow-striped Brush-Finch (Atlapetes citrinellus), the only species of bird endemic to the Argentinean Yungas, is a core species for seed dispersal. Of 30 species of fleshy fruit consumed, 16 were dispersed through endozoochory. The Yellow-striped Brush-Finch mostly used the ‘cut or mash’ method of handling fruit, in which reasonably large seeds (>0.04 g) were discarded or swallowed equally. Medium-sized and small seeds were more often swallowed than discarded. Although the fruits consumed were mostly understorey species, there was no difference in the consumption of fruit from forest understorey or canopy when total fruit abundance in vertical strata was considered. By using interaction network metrics, we determined that the role of Yellow-striped Brush-Finches in seed dispersal during the rainy season was more important at higher altitudes and in the southern sector of its distribution. Our findings support the idea that the Yellow-striped Brush-Finch must be considered a core seed-disperser of understorey and canopy fruits. Use of network metrics is an effective way to assess the importance of individual species in a network, allowing restoration and conservation efforts to be focussed on environments in which these species occur. Fil: Ruggera, Román Alberto. Universidad Nacional de Tucumán. Facultad de Ciencias Naturales e Instituto Miguel Lillo. Instituto de Ecología Regional; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina Fil: Gomez, Maria Daniela. Universidad Nacional de Jujuy. Facultad de Ciencias Agrarias; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina Fil: Blendinger, Pedro Gerardo. Universidad Nacional de Tucumán. Facultad de Ciencias Naturales e Instituto Miguel Lillo. Instituto de Ecología Regional; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina

Abiotic and biotic changes caused by forest fragmentation have led to the decline of many plant species. We sought to investigate how biotic (liana and bamboo cover) and abiotic (soil moisture, litter depth, and canopy openness) factors affect the total abundance and the numbers of individuals of Psychotria vellosiana Benth. at each stage of its life cycle (seedlings, juvenile I and II, adult reproductive and vegetative) in a fragmented landscape. P. vellosiana was selected because it is a forest species, important for fauna, especially ants and birds in the understory, and is highly abundant in semideciduous Atlantic forest areas. We hypothesised that fragments with less humidity, greater litter depth, greater canopy openness, and more liana and bamboo cover would contain fewer individuals at all five life cycle stages of that species. Ten 0.01 ha plots were set up in semideciduous Atlantic Forest fragments, and all individuals of P. vellosiana were tagged and measured. The study also measured canopy openness, soil moisture, litter depth, and bamboo and liana cover. Our results indicated that there was a negative relationship between liana and bamboo cover at all stages of the life cycle of P. vellosiana. This is one of the few studies that has investigated environmental effects on all stages of the life cycle of a plant population, and demonstrates that liana and bamboo cover can affect all stages of plant growth and development. Despite some restrictions, we can affirm that forest species are threatened by fragmentation processes, and that the main threat to local populations of P. vellosiana is liana and bamboo cover.

We collected field and remotely sensed data spanning 10 years after three 2003 Montana wildfires to monitor ecological change across multiple temporal and spatial scales. Multiple endmember spectral mixture analysis was used to create post-fire maps of: char, soil, green (GV) and non-photosynthetic (NPV) vegetation from high-resolution 2003 hyperspectral (HS) and 2007 QuickBird (QB) imagery, and from Landsat 5 and 8 imagery collected on anniversary dates in 2002, 2003 (post fire), 2004, 2007 and 2013. Initial estimates of char and NPV from the HS images were significantly correlated with their ground-measured counterparts (ρ=0.60 (P=0.03) and 0.68 (P=0.01) respectively), whereas HS GV and Landsat GV were correlated with canopy GV (ρ=0.75 and 0.70 (P=0.003) respectively). HS imagery had stronger direct correlations with all classes of fine-scale ground data than Landsat and also had stronger predictive correlations with 10-year canopy data (ρ=0.65 (P=0.02) to 0.84 (P=0.0003)). There was less than 5% understorey GV cover on the sites initially, but by 2013, it had increased to nearly 60% regardless of initial condition. The data suggest it took twice as long for understorey GV and NPV to replace char and soil as primary ground cover components on the high-burn-severity sites compared with other sites.

The extent to which prescribed fires affect forest structure and habitats of vertebrate species is an important question for land managers tasked with balancing potentially conflicting objectives of vegetation and wildlife management. Many insectivorous bats forage for insect prey in forested habitats, serving as the primary predators of nocturnal forest insects, and are potentially affected by structural changes in forests resulting from prescribed fires. We compared forest-stand characteristics of temperate oak–hickory forests, as measured with airborne laser scanning (light detection and ranging, LiDAR), with categorical estimates of burn severity from prescribed fires as derived from Landsat data and field-based Composite Burn Indices, and used acoustic monitoring to quantify activity of insectivorous bats in association with varying degrees of burn severity (unburned habitat, low severity and medium severity). Forest-stand characteristics showed greatest separation between low-severity and medium-severity classes, with gap index, i.e. open-air space, increasing with degree of burn severity. Greater mid-storey density, over-storey density and proportion of vegetation in the understorey occurred in unburned habitat. Activity of bats did not differ with burn severity for high-frequency (clutter-adapted or closed-space foragers) or low-frequency (edge or open-space foragers) bats. Results indicate that differing degrees of burn severity from prescribed fires produced spatial variation in canopy structure within stands; however, bats demonstrated no shifts in activity levels to this variation in canopy structure, suggesting prescribed fire during the dormant season, used as a management practice targeting desired changes in vegetation, is compatible with sustaining foraging habitat of insectivorous bats.

Mineral-sands mining in the semiarid and arid zone of south-eastern Australia is now a widespread disturbance that may adversely affect large areas of remnant vegetation, including mallee (Eucalyptus spp.) with hummock grass or spinifex (Triodia scariosa) understorey. No broad-scale restoration projects have been undertaken to revegetate mallee Eucalyptus species with spinifex. We report on the survivorship and relative importance (spatial coverage) of hand-planted tubestock 10 years after establishment in 2001, which included mallee Eucalyptus, Triodia scariosa, Acacia spp. and Hakea spp. These taxa are the dominant plants in a semiarid dune–swale system on a former mineral-sands mine licence area in semiarid, north-western Victoria. Mean survivorship of tubestock was 0.58 ± 0.04. Spinifex (Triodia scariosa), needlewood (Hakea) and several mallee species (Eucalyptus spp.) survived substantially better than the average of all tubestock-planted species, although Acacia spp. had low survivorships. Although the plantings were undertaken in the early stages of the most severe drought in the instrumental record (the ‘Millennium drought’), several taxa survived well and species such as spinifex established and developed ground coverage greater than the benchmark values for the ecological vegetation class of the location. We conclude that hand-planting of tubestock can achieve restoration objectives for this component of spinifex–mallee vegetation, even under extremely arduous conditions associated with long-term drought. We also herald the importance of taking a long-term view to the assessment of revegetation success, in this case 10 years.

The present study was conducted in a semideciduous Brazilian forest to verify whether there were architectural differences during development among tree species that differ in adult stature, such that understorey species maximise light interception and canopy and emergent species maximise height gain to rapidly reach high light environments. The crown illumination index and light interception index of individual trees as well as the variation in form among the understorey species were also analysed. Two understorey, one canopy and one emergent species were chosen, and the individuals were divided into height classes. Architectural comparisons among individuals were evaluated using allometry; crown illumination and light interception indices were compared among species. All comparisons were made within each height class. The two understorey species presented some differences in growth form, but both exhibited greater investment in the crown than did the canopy and emergent species. The crown illumination index did not differ among species, but the light interception index was higher for the understorey species. The results indicated that architectural differences between the studied species arise predominantly because species belong to different strata of the forest. Comparison within height classes was important because it allowed us to evaluate species architectural characteristics throughout plant development that cannot be detected using a single height-class comparison or that can be neglected if individuals of different heights are compared.

This is the first comprehensive camera trap study to examine hollow usage by wildlife in the canopy of trees. Eighty cameras directed at tree hollows were deployed across eight sites in nine species of eucalypt in north-east New South Wales. In total, 38 species (including 21 birds, 9 mammals and 8 reptiles) were recorded at hollow entrances over a three-month period. There was a significant difference between wildlife hollow usage associated with site disturbance and tree growth stage (ANOSIM, P > 0.05); however, there was no significant difference associated with tree hollow diameter (ANOSIM, P > 0.05). The level of anthropogenic disturbance at each site, including vegetation modification of the understorey, was a significant predictor of species presence. Despite the limitations of using camera traps in the canopy of trees this study demonstrates the potential to garner useful insights into the ecology and behaviour of arboreal wildlife.

Smoke measurements were made during grass and forest understorey prescribed fires as part of a comprehensive programme to understand fire and smoke behaviour. Instruments deployed on the ground, airplane and tethered aerostat platforms characterised the smoke plumes through measurements of carbon dioxide (CO2), carbon monoxide (CO), methane (CH4) and particulate matter (PM), and measurements of optical properties. Distinctions were observed in aerial and ground-based measurements, with aerial measurements exhibiting smaller particle size distributions and PM emission factors, likely due to particle settling. Black carbon emission factors were similar for both burns and were highest during the initial flaming phase. On average, the particles from the forest fire were less light absorbing than those from the grass fires due to the longer duration of smouldering combustion in the forest biomass. CO and CH4 emission factors were over twice as high for the forest burn than for the grass burn, corresponding with a lower modified combustion efficiency and greater smouldering combustion. This dataset reveals the evolution of smoke emissions from two different commonly burned fuel types and demonstrates the complexity of emission factors.

Climate warming is predicted to increase fire activity across the Eurasian boreal larch forest in the 21st century, which could have serious consequences on carbon storage. Quantifying the effects of fire disturbance on forest structure and aboveground net primary productivity (ANPP) could aid in our ability to predict future carbon storage on a regional and biome level. In this study, we examined the spatial heterogeneity of forest structure and ANPP on sites of varying fire severity and topographic position in a recently burned landscape in the Great Xing’an Mountains, China. Results indicated that after 11 years of vegetation regrowth, fire severity significantly affected forest regeneration ANPP. Spatial heterogeneities in forest regeneration ANPP were explained by both tree sapling density and understorey vegetation abundance. Although understorey vegetation productivity on average contributed 50% of total ANPP after fire, the increase in understorey productivity with fire severity could not offset the decrease in tree productivity in severely burned stands where tree sapling density was limited. Our results suggest that high-severity fire can decrease forest regeneration ANPP by altering forest structure in the early post-fire successional stage and that this shift in forest structure may influence future forest productivity trajectories over an extended period.

Mastication of understorey shrubs and small trees to reduce fire hazard has become a widespread forest management practice, but few empirical studies have quantified the effects of this mechanical treatment on actual fire behaviour and fire effects at the stand scale. We conducted experimental burns in masticated pine flatwoods with palmetto/gallberry understories, a common ecosystem of the Southern US Coastal Plain. Fire behaviour (flame height, rate of spread) and fire effects were compared between treated and untreated sites burned in the typical winter prescribed burning season. Mastication effectively reduced flame heights by 66%, but recovering shrubs (cover, height) influenced fire behaviour within six months following treatment, suggesting time-limited effectiveness. Trees had less crown scorch and bole char in masticated sites, but tree mortality was minimal on both treated and untreated sites. Consumption of masticated fuel was substantial across both treatments, but little duff was consumed under the moist soil conditions. When burning is conducted soon after treatment, mastication may effectively reduce fire behaviour in pine flatwoods sites, but the duration of treatment efficacy remains unclear.

Wildfires are common from summer to early fall in Patagonian forests of Argentina. Live fuel moisture content (LFMC) and leaf ignition are important factors for understanding fire behaviour. In this study, we determined seasonal LFMC and leaf ignition of some key fire-prone species of these forests, and their relationships with environmental variables. Species investigated were the native trees ñire (Nothofagus antarctica) and cypress (Austrocedrus chilensis), the understorey tree-like radal (Lomatia hirsuta) and laura (Schinus patagonicus), the bamboo caña colihue (Chusquea culeou), and the non-native black poplar (Populus nigra). LFMC differed among species, with caña colihue having lower values (LFMC 220%). Ignition characteristics differed among species (caña colihue>ñire>radal>cypress>laura>black poplar) and were inversely related to LFMC. Correlations between LFMC and environmental variables were highly significant for caña colihue, significant for ñire, radal, and laura, and weakly significant or non-significant for cypress and black poplar. These results contribute to our understanding of fire behaviour, and validate the fuel typology for Patagonian forests. At the same time, they add some useful knowledge for comparison with other fire-prone Mediterranean ecosystems around the world. Fil: Bianchi, Lucas Osvaldo. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Centro de Investigación y Extensión Forestal Andino Patagónico; Argentina Fil: Defossé, Guillermo Emilio. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Centro de Investigación y Extensión Forestal Andino Patagónico; Argentina. Universidad Nacional de la Patagonia; Argentina

Plantings of forage shrubs such as saltbush (Atriplex spp.) in the drier part of the crop–livestock zone of southern Australia have the potential to help fill feed autumn gaps, provide valuable feed during drought periods, and provide year-round groundcover, shelter for livestock and options for management of saline soils. However, the proportion of farms with forage shrub plantings and the extent of those plantings remain relatively low, with the rate of new plantings slowing over the past decade. Development of new forage-shrub options has been occurring with the aim of improving the feed value and adoption of forage shrubs. Using a whole-farm bio-economic optimisation model for a crop–livestock farming system in the low-rainfall Mallee region of southern Australia (Mallee MIDAS—model of an integrated dryland agricultural system), we explored how key attributes of forage-shrub plantings and the associated pasture understorey, such as biomass growth, digestibility and ease of establishment, can make forage shrub plantings economically more attractive to farmers. We found that saltbush types and forage-shrub options with improved feed quality characteristics will offer the opportunity for improved economic returns and increased profitability from larger plantings compared with existing options. Improving feed quality was more important than increasing the growth rates of saltbush plants. Results still indicate only a niche role in farming systems, with profit typically being greatest when using relatively small areas (

In ecosystems with frequent surface fires, fire and fuel heterogeneity at relevant scales have been largely ignored. This could be because complete burns give an impression of homogeneity, or due to the difficulty in capturing fine-scale variation in fuel characteristics and fire behaviour. Fire movement between patches of fuel can have implications for modelling fire spread and understanding ecological effects. We collected high resolution (0.8×0.8-cm pixels) visual and thermal imaging data during fire passage over 4×4-m plots of mixed fuel beds consisting of pine litter and grass during two prescribed burns within the longleaf pine forests of Eglin Air Force Base, FL in February 2011. Fuel types were identified by passing multi-spectral digital images through a colour recognition algorithm in ‘Rabbit Rules,’ an experimental coupled fire-atmosphere fire spread model. Image fuel types were validated against field fuel types. Relationships between fuel characteristics and fire behaviour measurements at multiple resolutions (0.8×0.8cm to 33×33cm) were analysed using a regression tree approach. There were strong relationships between fire behaviour and fuels, especially at the 33×33-cm scale (R2=0.40–0.69), where image-to-image overlap error was reduced and fuels were well characterised. Distinct signatures were found for individual and coupled fuel types for determining fire behaviour, illustrating the importance of understanding fire-fuel heterogeneity at fine-scales. Simulating fire spread at this fine-scale may be critical for understanding fire effects, such as understorey plant community assembly.

The genus Ruscus (Asparagaceae) consists of evergreen, woody monocot shrubs with modified photosynthetic stems (phylloclades) that occur in dry, shaded woodland areas of the Mediterranean Basin and southern Europe. The combined drought and shade tolerance of Ruscus species challenges the ‘trade-off model’, which suggests that plants can be either drought or shade adapted, but not both. To clarify the potential mechanisms that enable Ruscus species to survive in shaded environments prone to pronounced soil drought, we studied form–function relations based on a detailed trait survey for Ruscus aculeatus L. and Ruscus microglossum Bertol., focusing on gas exchange, hydraulics, morphology, anatomy, and nutrient and isotope composition. We then compared these trait values with published data for other species. R. aculeatus and R. microglossum exhibited numerous traits conferring drought and shade tolerance via reduced demand for resources in general and an ability to survive on stored water. Specific traits include thick phylloclades with low rates of maximum photosynthetic CO2 assimilation, low stomatal conductance to water vapour (gs), low respiration rate, low light compensation point, low shoot hydraulic conductance, low cuticular conductance, and substantial water storage tissue. Ruscus carbon isotope composition values of –33 ‰ were typical of an understory plant, but given the low gs could be associated with internal CO2 recycling. Ruscus appears to be a model for extreme dual adaptation, both physiologically and morphologically, enabling its occupation of shaded sites within drought prone regions across a wide geographical range, including extremely low resource understory sites.

Context A puzzling aspect of microtine population fluctuations is the damping out or collapsing of cycles over the last three decades, particularly in northern Europe. Occasional population fluctuations of Microtus may also have been damped out in temperate and boreal forests of the Pacific North-west of North America. One cause might be the presence of cattle (Bos taurus) grazing in forest habitats that offer summer forage. Aims We tested hypotheses (H) that abundance, population fluctuations, and demographic parameters of reproduction, recruitment and survival, of Microtus pennsylvanicus would be driven by understory plant productivity. Two predictions follow from this hypothesis: (H1) enhanced abundance and demography in fertilised stands, and (H2) reduced abundance and demography in stands with cattle grazing. Methods Study areas were located in ‘grazed’ and ‘ungrazed’ young forests in south-central British Columbia, Canada. Each study area had four replicate units of unfertilised and repeatedly fertilised stands. Herbaceous vegetation and meadow vole (M. pennsylvanicus) populations were sampled from 1993 to 2002. Key results Mean abundance of total herbs, grasses, and fireweed (Epilobium angustifolium) increased dramatically (8 to 34 times higher) with fertilisation in the ungrazed stands. Mean abundance of meadow voles was 3.1 to 8.5 times higher in the nutrient-enriched herbaceous vegetation in the ungrazed fertilised than grazed fertilised stands. Demographic variables also followed this pattern of abundance. Except for two years, mean abundance of meadow voles was similar between fertilised and unfertilised stands at the grazed area, with some degree of fluctuations generated in grazed stands. Thus, H1 and H2 were at least partly supported for M. pennsylvanicus in fertilised stands. Conclusions In high-quality habitats where cover and other attributes of vegetation are substantial enough to generate population increases and fluctuations of Microtus, grazing of vegetation by cattle or other livestock may indeed lead to potential collapse of fluctuations. Degree of grazing pressure would be crucial, but considering the widespread nature of grazing in the continuum of post-harvest forested sites in the Pacific North-west of North America, moderate to heavy grazing pressure is common. Implications Reductions in populations of microtines have serious consequences for predator communities and other ecological functions.

A trade-off between shade tolerance and growth in open conditions is widely believed to underlie the dynamics of humid forests. Little is known about how the growth versus shade tolerance trade-off interacts with other major trade-offs associated with differential adaptation to major environmental factors besides light. We asked whether the growth versus shade tolerance trade-off differed between subtropical rainforest tree assemblages native to basaltic (fertile) and rhyolitic (infertile) soils in northern New South Wales, because of the allocational costs of adaptation to low nutrient availability. Seedling relative growth rates of six basalt specialists and five rhyolite specialists were measured in a glasshouse and the minimum light requirements of each species were quantified in the field by determining the 10th percentile of juvenile tree distributions in relation to understorey light availability. A similar range of light requirements was observed in the two assemblages, and although the two fastest growing species were basalt specialists, seedling growth rates did not differ significantly between the two substrates. The overall relationship between light requirements and growth rate was weak, and there was no compelling evidence that the slope or elevation of this relationship differed between the two assemblages. Growth rates were significantly correlated, overall, with specific leaf area, and marginally with leaf area ratio. The apparent similarity of the growth versus shade tolerance trade-off in the two suites of species could reflect effects of leaf nutrient content on respiration rates; basalt specialists tended to have a smaller root mass fraction, but this may have been offset by the effects of leaf nitrogen status on respiration rates, with higher respiration rates expected on fertile basaltic soils. However, the results might also partly reflect impairment of the field performance of two basalt specialists that were heavily attacked by natural enemies.

The environmental, economic and social impacts of wildfires depend on spatial patterns of fire severity. An understanding as to how drivers of fire severity vary across broad vegetation communities exists. However, examination of variation within communities in response to gradients of moisture has received little attention so far. This study examined whether relationships between environmental variables (i.e. fire weather, topography and fuel age) and fire severity were modified by increasing mean annual precipitation. Understorey fires were more likely to occur in young fuels (i.e.

Understanding how animals use available habitat and how disturbance events such as fire influence habitat use is crucial to wildlife management. Relationships between home-range size of long-nosed bandicoots (Perameles nasuta) and vegetation type and fire effects on food availability and vegetation cover were explored. Home ranges and movement of P. nasuta were mapped in burnt and unburnt vegetation using radio-tracking. Compositional analysis was used to study their habitat associations. In 2004, six months after wildfire, no significant relationships were found between home-range size and vegetation type. In 2005, there was a preference for dry and wet forest over heath and disturbed areas. In both years, in ranges that contained both burnt and unburnt vegetation, there was a preference for unburnt vegetation. Home-range size was positively related to the bodyweight of individuals. Fire did not significantly alter home-range size, but did influence the way animals used their home range. Dense understorey might provide vital shelter from predators, and may be particularly important after fire. Wildfire and prescribed burning are major forms of disturbance in many natural areas and this study suggests the importance to P. nasuta of retaining unburnt patches when conducting hazard-reduction burning.

Elevated atmospheric CO2 concentrations (ca) will undoubtedly affect the metabolism of tropical forests worldwide; however, critical aspects of how tropical forests will respond remain largely unknown. Here, we review the current state of knowledge about physiological and ecological responses, with the aim of providing a framework that can help to guide future experimental research. Modelling studies have indicated that elevated ca can potentially stimulate photosynthesis more in the tropics than at higher latitudes, because suppression of photorespiration by elevated ca increases with temperature. However, canopy leaves in tropical forests could also potentially reach a high temperature threshold under elevated ca that will moderate the rise in photosynthesis. Belowground responses, including fine root production, nutrient foraging and soil organic matter processing, will be especially important to the integrated ecosystem response to elevated ca. Water use efficiency will increase as ca rises, potentially impacting upon soil moisture status and nutrient availability. Recruitment may be differentially altered for some functional groups, potentially decreasing ecosystem carbon storage. Whole-forest CO2 enrichment experiments are urgently needed to test predictions of tropical forest functioning under elevated ca. Smaller scale experiments in the understorey and in gaps would also be informative, and could provide stepping stones towards stand-scale manipulations.

White ash results from the complete combustion of surface fuels, making it a logically simple retrospective indicator of surface fuel consumption. However, the strength of this relationship has been neither tested nor adequately demonstrated with field measurements. We measured surface fuel loads and cover fractions of white ash and four other surface materials (green vegetation, brown non-photosynthetic vegetation, black char and mineral soil) immediately before and after eight prescribed fires in four disparate fuelbed types: boreal forest floor, mixed conifer woody slash, mixed conifer understorey and longleaf pine understorey. We hypothesised that increased white ash cover should correlate significantly to surface fuel consumption. To test this hypothesis, we correlated field measures of surface fuel consumption with field measures of surface cover change. Across all four fuelbed types, we found increased white ash cover to be the only measure of surface cover change that correlated significantly to surface fuel consumption, supporting our hypothesis. We conclude that white ash load calculated from immediate post-fire measurements of white ash cover, depth and density may provide an even more accurate proxy for surface fuel consumption, and furthermore a more physically based indicator of fire severity that could be incorporated into rapid response, retrospective wildfire assessments.

Catastrophic fires in wet forest have been highlighted as examples of drivers that overcome community resilience by altering feedback processes such that ecosystems are shifted into alternative, often less-desirable stable states. Recent successive lava-ignited wildfires, in slow-growing evergreen Myrtaceae-dominated mesic and wet forests at Hawaii Volcanoes National Park, provided an ideal opportunity to examine how forest species’ responses differ after single and repeated fires. In mesic (Metrosideros polymorpha–Dicranopteris linearis) and wet (Metrosideros–Cibotium glaucum) forests, the first fire was stand-replacing where 99% of the dominant overstorey trees (M. polymorpha) were top-killed; however, nearly half of these individuals survived by basal sprouting. The second fire dramatically increased mortality by killing the basal sprouts. Similarly, native tree fern C. glaucum survival was significantly reduced after repeated fires in the wet forest. The composition of the understorey in both communities after repeated fires differed in unexpected ways from once-burned and unburned forests. Repeated fires resulted in lower tree survival and rapid occupation by aggressive herbaceous species, potentially limiting tree growth and recruitment. The expected consequence is that native forest recovery will be delayed or even prevented by feedback processes established post-fire serving to maintain novel treeless alternate states.

Agricultural intensification has led to the dramatic decline of buloke (Allocasuarina luehmannii) and the plant communities it dominates in southern Australia. Conservation of remnant buloke woodlands and revegetation of agricultural land are both required for the persistence and improved ecological function of this threatened community. We examined the effect of proximity of mature buloke trees on early sapling survival, to provide guidelines for revegetation aimed at enhancing degraded remnants. We planted buloke saplings at different distances from the base of remnant mature trees at a site in western Wimmera, Victoria, with and without herbaceous competition. Mature buloke trees altered most soil nutrients (positively), soil water content (negatively) and soil conductivity (positively) at different gradients from the tree base, depending on the factor measured. Mature buloke trees had a strong negative effect on conspecific sapling survival in the first summer after planting in both the presence and absence of an herbaceous understorey, possibly because of the strong effect of trees on soil moisture. Competition from mature buloke was high nearest to the trees (up to 9 m from tree base), but competition from the native understorey also appeared important for saplings in the tree gaps, as evidenced by their improved survival when the understorey was removed. We suggest that to establish buloke saplings in areas where mature trees already occur (i.e. enhancement plantings around isolated paddock trees), planting tubestock outside the canopy of mature buloke is necessary to enhance establishment success.

Increasing size and severity of wildfires have led to an interest in the effectiveness of forest fuels treatments on reducing fire severity and post-wildfire fuels. Our objective was to contrast stand structure and surface fuel loadings on treated and untreated sites within the 2002 Rodeo–Chediski Fire area. Data from 140 plots on seven paired treated–untreated sites indicated that pre-wildfire treatments reduced fire severity compared with untreated sites. In 2011, coarse woody debris loading (woody material>7.62cm in diameter) was 257% higher and fine woody debris (woody material

Calothamnus quadrifidus subsp. teretifolius A.S.George & N.Gibson is a short-range endemic shrub whose habitat has been greatly reduced by clearing for agriculture. Reproductive output was high in all populations sampled, although there were large differences among populations in fruit set, the number of seeds per fruit and seed germination. These traits showed no relationship to population size, degree of isolation, or fragment size, which contrasts strongly with the patterns found in a widespread congener. Demographic studies in remnants with an intact understorey showed stable adult populations with continuous seedling recruitment. In contrast, there was consistent widespread failure of seedling and juvenile recruitment in degraded roadside remnants that also showed significant mortality of reproductive adults. In these degraded remnants, recruitment failure appears to be the primary cause of species decline.