Hollow selection by vertebrate fauna in forests of southeastern Australia and implications for forest management

We examined the types of hollows, and types of hollow-bearing trees, occupied by vertebrate fauna in temperate eucalypt forests in southeastern Australia. Hollow-bearing trees are selected for retention in wood production forests to mitigate the effects of logging on hole-nesting fauna. A total of 471 hollows was examined in 228 trees felled as part of routine logging operations. Fauna had occupied 43% of all hollows (?2cm minimum entrance width; ?5cm depth). Hollows with small (2-5cm), medium (6-10cm) and large (>10cm) minimum entrance widths had occupancy rates of 29, 44 and 62%, respectively. The internal dimensions of hollows, especially hollow depth, were the best predictors of hollow occupancy, even when variables measured at the tree and site levels were considered. Fauna occupied 57% of all hollow-bearing trees. In a Poisson regression model, the number of hollows in trees that contained evidence of occupancy was positively associated with: (1) the total number of hollows visible in the tree; (2) the proportion of the tree's crown that contained dead branches; and (3) tree diameter. The number of different vertebrate species that occupied trees was positively associated with the same explanatory variables except tree diameter. Thus, our results suggest that trees with multiple hollows and dead branches in the crown should be preferentially selected for occupancy by hollow-using fauna. Our results suggest that trees with the largest diameter are not the most suitable for retention. Possibly because they contain proportionally fewer hollows with small entrances, which are favoured by some vertebrate species.     

Location of roosts of the lesser long-eared bat Nyctophilus geoffroyi and Gould's wattled bat Chalinolobus gouldii in a fragmented landscape in south-eastern Australia

The location of roosts of two species of vespertilionid bats, the lesser long-eared bat (Nyctophilus geoffroyi) and Gould’s wattled bat (Chalinolobus gouldii), was investigated in a remnant vegetation-farmland mosaic and adjacent floodplain forest in south-eastern Australia. A total of 45 individuals of N. geoffroyi and 27 C. gouldii were fitted with radio transmitters, which resulted in the location of 139 and 89 roosts respectively. Selection of roosting habitat showed both inter- and intra-specific differences. At the landscape level, locations of roosts used by male and female N. geoffroyi differed markedly. Most males roosted in the farmland mosaic within 3 km (mean 1.9±2.9 km) of where they were captured while foraging in remnant vegetation. In contrast, roost sites of females were predominantly in the floodplain forest, 6-12 km from their capture site in farmland (mean for all females, 6.7±2.9 km). All maternity roosts were in the extensive floodplain forest, 4-10 km from foraging areas. Distances moved by this species were greater than previously recorded and further than predicted by flight morphology. Most C. gouldii roosted in the floodplain forest, 4-10 km from their capture site (6.9±1.6 km). Within the floodplain forest, both species roosted in areas that had higher densities of hollow-bearing trees than generally available; dead hollow-bearing trees for N. geoffroyi and large, live trees for C. gouldii. The scale of movements undertaken by these species means that they can obtain resources from multiple landscape elements. Both species used different habitats for roosting and foraging despite the energetic costs of commuting relatively large distances. Conservation of bat populations in rural environments needs to be considered at the landscape scale, with particular attention to identifying landscape elements that provide key resources.     

On predicting the presence of birds in Eucalyptus forest types

We examine the relationship between the number of bird species and environment within 500 000 ha of eucalypt forests in south-eastern New South Wales, Australia. Birds were surveyed at 39 sites within 31 eucalypt communities, which were, in turn, scored by altitude, temperature, rainfall, basal areas of trees and levels of the nutrients nitrogen, phosphorus, potassium and magnesium in the eucalypt foliage.

Ninety bird species were recorded. Numbers per site, averaged over the whole sample period, ranged between 20 and 38 over all surveys, 24 and 42 in ‘summer’ (October to March) when migrant species were present, and 13 and 38 in ‘winter’ (April to September). A forward stepwise Poisson regression model was used to fit bird species richness to the environmental variables. Over all surveys and in ‘summer’, foliar magnesium and tree basal area (including the basal area of dead trees) were significantly (positive) correlated with the number of bird species. In ‘winter’ the correlations were with altitude and temperature (both negative), presumably the result of emigration of species that avoid cold weather, and tree basal area (positive).

The positive association of number of species over all surveys and in ‘summer’ with tree basal area, including dead trees, and foliar magnesium may index the level of forest maturity and productivity.

Forest management directed solely to timber production reduces the basal area and the number of dead trees and may thereby reduce bird species richness permanently.

A methodology is offered, based on the relationship between the physical environment and the more productive eucalypt communities, for determining forest areas containing the most species of birds.     

Agricultural landscape modification increases the abundance of an important food resource: Mistletoes, birds and brigalow

Agricultural landuse alters landscape pattern, with important consequences for native species. Complex responses to changes in landscape pattern may be observed for species with strong inter-specific relationships. We investigate how the abundance of an ecologically important food resource, the grey mistletoe (Amyema quandang), is influenced by the interactive influences of human-modified landscape pattern, bird disperser abundance and host condition. Mistletoe abundance was estimated in brigalow (Acacia harpophylla) dominated remnants in three separate study areas with differing landscape patterns. Negative binomial generalised linear models of mistletoe abundance were tested with combinations of seven explanatory variables: study area, landscape connectivity and edge contrast, patch shape, bird disperser abundance, brigalow foliage cover and basal area of standing dead trees. Ranking of model averaged parameter estimates showed that study area, bird disperser abundance, patch shape, dead trees and connectivity had the strongest influence on A. quandang abundance. Mistletoe abundance apparently increased with landscape modification, particularly in narrow linear patches, but may be limited by the availability of seed dispersers and host condition. Given high landscape modification and ongoing degradation, management should be targeted towards maintaining brigalow remnant condition to ensure bird and mistletoe populations can be supported in the long-term.     

The conservation implications of bird reproduction in the agricultural “matrix”: a case study of the vulnerable superb parrot of south-eastern Australia

Where agriculture has recently been imposed on natural systems, habitats that are modified, but not destroyed, within the agricultural matrix, are often, undervalued for their conservation benefits. Ecological research in the agricultural matrix in such landscapes has been limited in many countries. Yet many organisms live and breed in these landscapes. This paper outlines a large-scale case study of the vulnerable superb parrot that breeds in trees in the agricultural matrix of south-eastern Australia. Superb parrot nest trees were located, measured and compared with a set of randomly chosen non-nest trees. Increasing tree diameter had the largest influence over whether a superb parrot nested in a tree. There was a strong preference for nesting in dead trees and Blakely's red gum. There was limited eucalypt regeneration surrounding trees. The large size and poor health of nest trees requires urgent habitat management to provide alternative nest sites and regenerate trees across the whole agricultural matrix. This will require a long-term vision on the scale of centuries.     

Lizard microhabitat and fire fuel management

For many species, dead vegetation is important microhabitat necessary for survival and reproduction. We compared the use of three categories of trees: living, dead standing and dead prone, within and among four species of phrynosomatid lizard (Sceloporus undulatus, Sceloporus graciosus, Urosaurus ornatus, and Uta stansburiana) on the Colorado Plateau during 1990, 1992 and 2000. All four species used dead trees (both prone and standing) more frequently than live trees, despite an opposite pattern of availability. U. ornatus used dead standing more often than dead prone trees, reflecting this lizard's arboreal nature. Tree use did not differ among lizard species, and the lizard species by tree category interaction was not significant. Current policy mandates the removal of dead vegetation and debris on US Federal lands as basic maintenance in order to decrease fire risk. Active removal of “fuel” may limit the local distribution, abundance, and diversity of these lizards, which include dead trees in their microhabitat for shelter, perching, foraging, courting, and defending territories.     

Predicting reproductive success of insect- versus bird-pollinated scattered trees in agricultural landscapes

Scattered trees are set to be lost from agricultural landscapes within the next century without sustained effort to increase recruitment. Thus, understanding the reproductive dynamics of scattered tree populations will be critical in determining how they can contribute to population restoration. The distance between conspecifics should be a key predictor of reproductive success, as more isolated trees are expected to receive fewer pollinator visits and experience increased transfer of self-pollen during longer pollinator foraging bouts. Further, isolation effects should be greater in species with less mobile pollinators. Here we contrast the effects of plant isolation on reproductive success of two species of eucalypt “paddock trees”, Eucalyptus camaldulensis and Eucalyptus leucoxylon, with insect- and bird-pollination, respectively. Seed production was not affected by tree isolation in either the insect- or bird-pollinated species and once outliers were removed, neither was there an effect on germination rate. As somatic mutations may bias outcrossing rate estimates, we initially screened our microsatellite markers for mutations but found no variation in microsatellite profiles throughout the canopy of trees. Individual outcrossing rates did not decline with increasing tree isolation in either the insect- or bird-pollinated species, though there was considerable variation in these rates at large distances, suggesting that pollination becomes unreliable with increasing tree isolation. We found that pollination distances have likely increased in tree species in agricultural landscapes, and that this may be facilitated by introduced honeybees in the case of E. camaldulensis. We therefore suggest that even isolated trees of these species produce seed of sufficient quantity and quality to contribute to population restoration.     

Health of remnant woodlands in fragments under distinct grazing regimes

Fragmented remnant woodlands in agricultural landscapes are of high conservation value world-wide. Many eucalypts in agricultural landscapes of Australia are in decline. We aimed to investigate nutrient enrichment as a process that may contribute to eucalypt decline. We studied remnant woodlands that had been exposed to distinct recent and current livestock grazing treatments: Currently Intense Grazed; Recently Intense Grazed (until 3 years ago); Recent Intermediate Grazed; and Recent Lightly Grazed by livestock. We assessed soil nutrient status and penetrability, eucalypt foliar nutrition and stable isotope ratios for N and C, attributes of understorey vegetation, and tree health. Soils of the Currently Intense Grazed treatment had high levels of ammonium and Colwell-P. Total N, P, C:N ratio and soil penetrability were generally high in Currently Intense Grazed and Recently Intense Grazed treatments relative to Recent Intermediate Grazed and Recent Lightly Grazed treatments. Foliar N, N stable isotope ratios, P and carbon stable isotope ratios (δ¹³C) were generally higher (less negative δ¹³C) in trees on Currently Intense Grazed and Recently Intense Grazed treatments than in trees on Recent Intermediate Grazed and Recent Lightly Grazed treatments. Soil surface litter, tall and low shrubs and rock were positively correlated with tree health. Grasses and eucalypt foliar N, P and δ¹³C were negatively correlated with tree health. Soil nutrient enrichment increased with increasing grazing intensity and was associated with increased weed invasion and with poor tree health that was in turn correlated to increased foliar N and P and less negative δ¹³C in woodland trees in this study. We argue that minimising soil nutrient enrichment of fragmented remnant woodlands is important, given the association of elevated soil nutrition with poor tree health, to ensure the persistence of eucalypts in agricultural landscapes.     

Evaluating simultaneous impacts of three anthropogenic effects on a floodplain-dwelling marsupial Antechinus flavipes

Regulation of river flows has altered floodplain ecosystems around the world. Floods are less frequent, which leads to reduction of favourable environmental conditions for many terrestrial and aquatic organisms adapted to natural flooding regimes. In Australia, the Murray River floodplains have been subjected to decline in inundations, to extensive logging and to removal of fallen timber. The yellow-footed antechinus (Antechinus flavipes) is the only small, native, ground-dwelling/semi-arboreal mammal on most floodplains of south-eastern Australia, yet the effects of floods on its population dynamics largely are unknown. Here, we found positive effects of proximity to flooding, higher woodloads and of abundance of large, hollow-bearing trees on antechinus numbers. Mean trapping rates of antechinuses were lowest in 2003 following a 3-year period with no inundation, higher in 2004 following the first breeding season during a small, controlled flood in 2003, and higher again in 2005, following a small, controlled flood in 2004. In 2004 and 2005, trapping rates declined with distance from floodwaters. This study provides evidence for the benefits of using management flows to inundate floodplains, conserving large trees and ensuring high woodloads in floodplains for sustaining populations of the yellow-footed antechinus.     

Roost selection by barbastelle bats (Barbastella barbastellus, Chiroptera: Vespertilionidae) in beech woodlands of central Italy: consequences for conservation

We investigated roost selection by Barbastella barbastellus in a mountainous area of central Italy. Twenty-five bats, mostly lactating females, were radio-tracked to 33 roost trees. Trees in unmanaged woodland were favoured as roost trees; woodland subject to limited logging was used in proportion to availability, and areas where open woodland and pasture occurred were avoided. Selection depended on tree condition (dead beech trees were preferred) and height (roost trees were taller than random ones). Cavity selection was based on cavity type, height and entrance direction: roost cavities were mainly beneath loose bark, at a greater height above ground and facing south more frequently than random cavities. Untouched areas of mature woodland should be preserved to provide roosting conditions for B. barbastellus. In logged areas, harvesting protocols should save dead and mature trees; frequent roost switching and small colony size imply that large numbers of roost trees are needed.     

Factors affecting site occupancy by woodland bird species of conservation concern

Significant biodiversity loss is characteristic of agricultural landscapes worldwide. Biodiversity recovery efforts in such landscapes can be hamstrung by a paucity of information on factors affecting species’ distributions, particularly for threatened and/or declining species. The temperate woodlands of south-eastern Australia have been extensively modified for agriculture and numerous bird taxa are declining. We have explicitly identified habitat and landscape attributes of woodland remnants affecting site occupancy by 13 woodland bird species of conservation concern.Using case-control data and linear logistic regression, we found that site occupancy for each species was related to both habitat and landscape variables. Habitat variables of particular importance included those in the ground layer (an abundance of leaf litter, an intact surface crust of mosses and lichens and a scarcity of annual grasses) and overstorey (a scarcity of eucalypt dieback and an abundance of mistletoe). Landscape variables strongly affecting site occupancy included the number of paddock trees and the area of native grass within 500 m of a site. Many of our study species were found most often in regrowth remnants.Our findings indicate a gap between current conservation practices and the actual habitat requirements of woodland bird species of conservation concern. Successful management will require protection and/or rehabilitation of the ground layer and overstorey of woodland remnants and sympathetic management of the surrounding landscape. It also will require managers to go beyond current practices of conserving old growth remnants and establishing replantings to maintaining and creating stands of woodland regrowth.     

Scattered trees in rural landscapes: foraging habitat for insectivorous bats in south-eastern Australia

Scattered trees and small patches of vegetation among farmland are typical of rural landscapes throughout the world, often comprising a significant proportion of remaining habitats for native fauna. Insectivorous bats can use such isolated resources owing to the high mobility of most species, but little is known of the relationship between bats and tree density, or of the impact of incremental loss of trees in the landscape. Bats were surveyed at 30 sites in south-eastern Australia, in five habitat categories representing a range of tree densities from remnant woodland blocks (>35 trees/ha) to sparsely scattered trees (<1 tree/ha), and open paddocks devoid of trees. Sampling was undertaken by using harp traps and ultrasonic bat detectors. The abundance of potential arthropod prey was assessed by using light traps. Eleven species of insectivorous bats were recorded and bats were widespread in all habitat categories; all species were recorded around scattered trees. Overall activity, as revealed by detectors, did not differ significantly between the four treed categories, but in open paddocks there was a lower level of activity and a different community composition. However, a regression model revealed a significant quadratic relationship between activity of bats and tree density, with highest activity at 20-30 trees/ha. All species were recorded in open paddocks, but for eight of the ten species this represented <7% of their total activity recorded across all habitat categories. For six species, significant positive correlations were found between activity levels and the abundance of potential arthropod prey. In contrast to bat detectors, trapping results showed a significant difference in overall abundance of bats between wooded habitats, with decreased abundance as tree density declined. This study highlights the value of scattered trees as foraging habitat for bats, and emphasizes that, in rural land mosaics, such small and isolated habitat components have value for the conservation of biodiversity, and require greater recognition and protection.     

The challenge of maintaining Atlantic forest biodiversity: A multi-taxa conservation assessment of specialist and generalist species in an agro-forestry mosaic in southern Bahia

Recent developments have highlighted the importance of forest amount at large spatial scales and of matrix quality for ecological processes in remnants. These developments, in turn, suggest the potential for reducing biodiversity loss through the maintenance of a high percentage of forest combined with sensitive management of anthropogenic areas. We conducted a multi-taxa survey to evaluate the potential for biodiversity maintenance in an Atlantic forest landscape that presented a favorable context from a theoretical perspective (high proportion of mature forest partly surrounded by structurally complex matrices). We sampled ferns, butterflies, frogs, lizards, bats, small mammals and birds in interiors and edges of large and small mature forest remnants and two matrices (second-growth forests and shade cacao plantations), as well as trees in interiors of small and large remnants. By considering richness, abundance and composition of forest specialists and generalists, we investigated the biodiversity value of matrix habitats (comparing them with interiors of large remnants for all groups except tree), and evaluated area (for all groups) and edge effects (for all groups except trees) in mature forest remnants. Our results suggest that in landscapes comprising high amounts of mature forest and low contrasting matrices: (1) shade cacao plantations and second-growth forests harbor an appreciable number of forest specialists; (2) most forest specialist assemblages are not affected by area or edge effects, while most generalist assemblages proliferate at edges of small remnants. Nevertheless, differences in tree assemblages, especially among smaller trees, suggest that observed patterns are unlikely to be stable over time.     

Diversity of dead wood inhabiting fungi and bryophytes in semi-natural beech forests in Europe

Saproxylic organisms are among the most threatened species in Europe and constitute a major conservation problem because they depend on the most important forestry product - dead wood. Diversity of fungal and bryophyte communities occurring on dead beech trees was analyzed in five European countries (Slovenia, Hungary, The Netherlands, Belgium and Denmark) considering tree level species richness (TLSR), country level species richness (CLSR), frequency distributions of species, occurrence of threatened species and relations between TLSR and decay stage, tree size and countries. Altogether 1009 trees were inventoried in 19 beech dominated forest reserves.The number of fungi in the full dataset was approximately three times larger (456 versus 161 species) and the proportion of low frequent species was higher than among bryophytes. The species richness of bryophytes and fungi was significantly different among countries considering both TLSR and CLSR. In addition the diversity patterns deviated considerably between the two groups of organisms. Slovenian sites appeared to be biodiversity hotspots for bryophytes characterized by high TLSR and CLSR and a high fraction of threatened species. Hungarian sites had somewhat lower bryophyte diversity, while the Atlantic region had deteriorated assemblages. Fungal species richness was very high in Denmark, but the Hungarian and Slovenian sites were richer in threatened and low frequency species. Tree size was better able to explain variation in TLSR in both organism groups than decay stage. TLSR was found to vary significantly between countries but the difference was most considerable in the case of bryophytes.The diversity patterns of both organism groups along the investigated geographical gradient appear to be influenced by both climatic and management related factors (forest history, dead wood availability and continuity, habitat fragmentation). There is no doubt that an increase in the abundance of dead wood in European beech forests will benefit diversity of saproxylic fungi and bryophytes, especially if a continuous presence of large diameter logs are secured within individual stands.     

Endangered crayfish in northern Japan: Distribution, abundance and microhabitat specificity in relation to stream and riparian environment

Japan’s only native crayfish species Cambaroides japonicus has been declining dramatically in the past few decades. For the purpose of conservation planning, twenty-two coastal streams were surveyed to investigate summer distributions of crayfish in relation to stream and riparian environment. Classification and regression trees were used to predict the occurrence and abundance of crayfish. The classification tree model with stream variables as predictors showed that crayfish would occur in swift or high gradient streams (correct classification rate = 91%). Within those streams, however, crayfish only inhabited depositional microhabitats, in which the areas are limited in availability. Crayfish were not found in gentle, low gradient streams containing abundant depositional microhabitats. This paradoxical distribution pattern was attributed to availability of boulder substrates in swift or high gradient streams. The regression tree model indicated that crayfish abundance was determined primarily by the percentage of boulder substrates and the presence of fish (observed vs. predicted r = 0.64).The classification tree model using only riparian variables indicated that the total woody plant (mainly broadleaf species) density followed by the percentage of early successional species such as alder and willow determined the splits of the tree model (correct classification rate = 95%). A leaf processing experiment on 10 riparian plant species suggested that crayfish preferred high nitrogen (or low C/N) leaves.These results suggest that swift or high gradient fishless streams associated with abundant cover in dense broadleaf forest serve conservation areas for this endangered crayfish, and that consideration of riparian composition may facilitate conservation efforts.     

Effects of fragmentation on pollinator abundance and fruit set of an abundant understory palm in a Mexican tropical forest

Tropical forest fragmentation affects both biodiversity and plant reproductive success when small, isolated fragments sustain a reduced diversity or abundance of pollinators. Fragmentation-related effects have been poorly investigated in the case of palms, an important structural and functional component of tropical forests. We examined the relationships between fragment size and diversity and abundance of flower visitors, and palm reproduction, by quantifying the arthropod fauna associated to inflorescences of the palm Astrocaryum mexicanum, and its fruit set, in fragments of different size. The sample yielded a total of 228,772 arthropods (10 orders, 60 species). Coleoptera was the predominant group (?50% of the species), followed by Hymenoptera (20%), while the remaining (30%) was distributed among the other eight orders. We found a predominance of pollinating insects (Coleoptera-Nitidulidae), representing 85% of all visitors. Pollinator abundance was negatively affected by fragmentation, with a 4.2-fold average difference between small (<35 ha) and large (114-700 ha) fragments. However, fruit set was relatively high (?0.7) and not affected by fragmentation during three reproductive seasons. This could be explained because small fragments retained remarkably high numbers of pollinators (1191.4/inflorescence) and by the high abundance of palms (and flowers) in fragments. Further research is needed, however, to assess if fragmentation restricts pollinator movements to plants within the fragments, leading to a reduction in genetic variation of the progeny present in forest remnants.     

Woodland trees modulate soil resources and conserve fungal diversity in fragmented landscapes

Resource islands around woody plants are thought to define the structure and function of many semiarid and arid ecosystems, but their role in patterning of soil microbial communities remains largely unexamined in dry environments. This study examined soil resource distribution and associated fungal communities in two Allocasuarina luehmannii (buloke) remnants of semiarid north-western Victoria, Australia. These savannah-like woodlands are listed as endangered due to extensive clearing for agriculture. We used the DNA-based profiling technique T-RFLP and ordination-based statistical methods to compare fungal community compositions in surface soils from two remnants (located 1.6 km apart) and three sampling positions (beneath individual buloke canopies; grassy inter-canopy areas; and adjoining cleared paddocks). Resource island formation beneath buloke trees was clearly evident in soil physicochemical properties (e.g. threefold concentrations of total carbon and nitrogen in canopy versus non-canopy soils). This heterogeneity of resources was moderately correlated with soil fungal community compositions, which were distinct for each sampling position. We argue that fungal composition patterns reflected multiple roles of fungi in dryland ecosystems, namely: responses of saprotrophic fungi to tree organic matter inputs; specificity of ectomycorrhizal fungi to tree rooting zones; and fungal involvement in biological soil crusts that variably covered non-canopy soils. Our data did not indicate that buloke canopy areas were particular hotspots of soil fungal diversity, but that they increased landscape-level diversity by supporting a distinct suite of fungi. In addition, we provide evidence of phylogenetic differentiation of soil fungal communities between our two remnants, which adds to growing evidence of fungal genetic structure at localised scales. These findings highlight the importance of remnant trees in conserving both soil resources and microbial genetic diversity. In addition, evidence of differentiation of soil fungal phylogenetics between nearby but isolated remnants suggests that conserving soil fungal diversity requires conservation of host habitats over their entire (remaining) range, and indicates previously unseen consequences of tree loss from extensively cleared landscapes.     

Do frugivorous birds assist rainforest succession in weed dominated oldfield regrowth of subtropical Australia?

Exotic plants often form the first woody vegetation that grows on abandoned farmland. If this vegetation attracts vertebrate frugivores which disperse the seeds of native plants, then native plants may recruit to such oldfield sites. However, there is debate about the extent to which exotic vegetation assists or suppresses the regeneration of native plants, and about its effects on faunal biodiversity. These issues were investigated in subtropical eastern Australia, where rainforests were cleared for agriculture in the 19th century, and where regrowth dominated by camphor laurel (Cinnamomum camphora, an exotic, fleshy-fruited tree) has become common on former agricultural land. The study assessed the assemblages of frugivorous birds, and the recruitment of rainforest plants, at 24 patches of camphor laurel regrowth. The patches were used by nearly all frugivorous birds associated with subtropical rainforest. Many of these birds (16 of 34 species) are considered to have a medium to high potential to disperse the seeds of rainforest plants, and eight of these were abundant and widespread in regrowth patches. Of 208 recorded plant species, 181 were native to local rainforest. The ratio of native to exotic species was higher amongst tree recruits than adult trees, both for numbers of species and individuals. Among native tree recruits, 79% of 75 species, and 93% of 1928 individuals, were potentially dispersed by birds. These recruits included many late-successional species, and there were relatively more individuals of late-successional, bird-dispersed native species amongst recruits than adult trees. The species richness, but not the abundance, of both frugivorous birds and of bird-dispersed rainforest trees decreased with distance from major rainforest remnants. Camphor laurel regrowth provides habitat for rainforest birds and creates conditions suitable for the regeneration of native rainforest plants on abandoned farmland. Careful management of regrowth dominated by fleshy-fruited exotic invasive trees can provide an opportunity for broadscale reforestation in extensively-cleared landscapes.     

Learning from a “benign neglect strategy” in a national park: Response of saproxylic beetles to dead wood accumulation

Increasing demands for firewood owing to rising energy costs have accelerated discussions about the amount of dead wood needed for conservation. A sharp increase in dead wood caused by bark beetles in a German national park provides lessons for management of commercial and protected forests. We investigated the effects of dead wood due to bark beetle infestation as well as tree senility on abundance and richness of saproxylic species of beetles. Increasing amounts of spruce dead wood and opening of the canopy by bark beetles had positive effects on the abundance of host-generalist, conifer-specialist, and red-listed saproxylic beetles. Broadleaf specialists were positively associated with the amount of broadleaf dead wood and negatively associated with canopy openness. Gradient analysis of beetle assemblages revealed two major environmental axes: canopy openness and amount of dead wood. We found a threshold for community divergence at a canopy openness of 23% (confidence interval CI: 11-49) and at an amount of dead wood of 64 m³ ha⁻¹ (CI: 35-160). Critically endangered species served as indicators of dense and open forests, but only when the amount of dead wood was high. Our results suggest that, to maintain saproxylic beetle assemblages, the amount of dead wood in commercial montane forests (at present ≈15 m³ ha⁻¹) needs to be tripled, with a focus on broadleaf wood in dense stands and spruce wood in open stands. For large protected areas in Europe, our data suggest that bark beetle infestation and senescence without active forest management improves habitat conditions for saproxylic beetles.     

Nesting habitat of the glossy black-cockatoo in central New South Wales

The reliance of cockatoos upon large hollows for nesting makes them vulnerable to any reduction in this resource. Species inhabiting forests managed for timber production are at risk because logging has the capacity to reduce hollow abundance significantly. In this study I identified the factors significantly associated with the selection of nest trees and nest sites by glossy black-cockatoos. Glossy black-cockatoos nested in vertical spouts in large trees. Nests were more likely to be located relatively high in senescent trees or standing dead trees (snags), factors most likely related to hollow suitability. As the density of potential nest hollows increased within a site, so to did the relative probability of it being used for nesting. The number of potential hollows serves as an index for the availability of suitable hollows. The persistence of glossy black-cockatoos within the study area will require careful management of nesting resources. Maximising the available hollow resource within known nesting areas is desirable. This is most efficiently achieved by facilitating the recruitment of large trees. This will require the exclusion of logging from nesting areas. Snags are a critical nesting resource. Information on snag dynamics is required and active intervention, such as the erection of nest boxes, may be necessary if unsustainable snag loss is occurring.