Use of remnant forest habitat by birds during winter in subtropical Australia: patterns and processes

1997 ◽  
Vol 3 (3) ◽  
pp. 262 ◽  
Author(s):  
Carla P. Catterall ◽  
Mark B. Kingston ◽  
Kate Park
Keyword(s):  
Structural Integrity ◽  
Interference Competition ◽  
Physical Structure ◽  
Native Forest ◽  
Ecological Processes ◽  
Noisy Miner ◽  
Habitat Differences ◽  
Eucalypt Forests ◽  
Remnant Forest ◽  
Subtropical Australia

The south-east Queensland region of subtropical Australia supports a high diversity of landbird species, many of which are migrants which visit lowland areas during winter. However, lowland habitats have been impacted by clearing and fragmentation of native forest types within the past 170 years. This paper considers the implications of loss and fragmentation of lowland eucalypt forests for birds in winter, by comparing the proportionate density of twelve selected species across 49 different cases representing a variety of structural habitat differences. There was little fragmentation effect on forest-dependant winter immigrant species down to about 10 ha. The smallest remnants had reduced proportionate abundances of forest-dependent species together with elevated abundances of two other species: Noisy Miner and Australian Magpie. Similar shifts in species composition occurred in association with a variety of types of change in native eucalypt forest, all involving alteration to physical structure incorporating reduction of foliage cover (at forest edges, in areas without understorey, in regenerating forest, on slopes and ridges, and after fires). We consider the ecological processes that might underlie these patterns, and suggest that: (1) habitat selection, possibly mediated and/or reinforced by interference competition from Noisy Miners, is a key process in the study system in winter; (2) habitat loss, rather than fragmentation, is likely to be the main cause of regional declines in forest-dependent winter migrants; and (3) the management of habitat for winter migrant birds within lowland eucalypt forests of this region should focus on maintaining and improving: (a) the overall percentage of lowland area covered by native forest, and (b) factors associated with the structural integrity (canopy and understorey cover, fire frequency, retention of complete microtopographic gradients) of remnant forest areas irrespective of their size, at least down to about 10 ha.

Structural Integrity System Based on an Object-Oriented Activity- and Product Model

1993 ◽  
Author(s):  
Morten Lovstad ◽  
Tor G. Syvertsen
Keyword(s):  
Computational Models ◽  
Structural Integrity ◽  
Oil And Gas ◽  
Physical Structure ◽  
Gas Production ◽  
Structural Safety ◽  
Actual State ◽  
Product Model ◽  
The North ◽  
Analysis Models

Abstract Huge steel or reinforced concrete structures in deep waters support the installations for oil and gas production in the North Sea. Steady operations in a hostile environment require that structural safety and integrity is maintained. For rapid evaluation and assessment of structural integrity in case of modifications or urgency situations, Structural Integrity Systems are established, comprising computational models and structural analysis programs. A major problem for structural assessment at short notice is to keep the analysis models updated and consistent with the actual state of the physical structure and the loadings. This paper proposes a layered approach for model integration, which enable maintenance of the models at a high level, from which detailed analysis models are derived in a consistent manner.

The ecological roles of logs in Australian forests and the potential impacts of harvesting intensification on log-using biota

2002 ◽  
Vol 8 (2) ◽  
pp. 121 ◽  
Author(s):  
D. B. Lindenmayer ◽  
A. W. Claridge ◽  
A. M. Gilmore ◽  
D. Michael ◽  
B. D. Lindenmayer
Keyword(s):  
Power Plants ◽  
Large Scale ◽  
Animal Movement ◽  
Structural Complexity ◽  
Ground Cover ◽  
Native Forest ◽  
Functional Roles ◽  
Standing Trees ◽  
Velvet Worms ◽  
Eucalypt Forests

A review is presented of the ecological values of logs in Australian eucalypt forests. Logs are a key component of stand structural complexity and have critical functional roles for forest biodiversity including:- (1) providing nesting and sheltering sites for biota, (2) providing foraging substrates for predators like snakes and predatory invertebrates such as velvet worms, (3) providing basking and hibernation sites for reptiles, (4) facilitating animal movement, (5) providing places for key social behaviours, (6) acting as plant germination sites, (7) providing substrates to promote the growth of fungi, (8) providing mesic refugia for organisms during drought and/or fire, and (9) contributing to heterogeneity in the litter layer and patterns of ground cover. Logs also play significant roles in nutrient cycling in forests. The role of logs is often ignored in forestry operations, including those where harvesting intensification will occur through the removal of dead and/or "defective" standing trees and logs under the guise of removing so-called waste or logging "residues". Recently proposed intensive large-scale forestry operations in the Australian native forest estate (e.g., biomass burning power plants and charcoal plants) have the potential to reduce stand structural complexity, alter forest ecosystem function and negatively impact upon log-dependent species in those part of the landscape where harvesting takes place. The risks of such impacts have not been adequately measured in Australia, but they need to be addressed urgently. Prescriptions for the retention and future recruitment of logs must be developed to avert possible losses of biodiversity.

scholarly journals Cats, canines, and coexistence: dietary differentiation between the sympatric Snow Leopard and Grey Wolf in the western landscape of Nepal Himalaya

2019 ◽  
Vol 11 (7) ◽  
pp. 13815-13821 ◽  
Author(s):  
Anil Shrestha ◽  
Kanchan Thapa ◽  
Samundra Ambuhang Subba ◽  
Maheshwar Dhakal ◽  
Bishnu Prasad Devkota ◽  
...  
Keyword(s):  
Local Community ◽  
Dietary Habits ◽  
Interference Competition ◽  
High Rate ◽  
Snow Leopard ◽  
Grey Wolf ◽  
Ecological Processes ◽  
Nepal Himalaya ◽  
Top Predators ◽  
Prey Limitation

Understanding the dietary habits of sympatric apex carnivores advances our knowledge of ecological processes and aids their conservation. We compared the diets of the sympatric Snow Leopard Panthera uncia and Grey Wolf Canis lupus using standard micro-histological analyses of scats collected from the western complex of Nepal Himalaya. Our study revealed one of the highest recorded contributions of livestock to the diet of top predators (55% for Grey Wolf and 39% for Snow Leopard) and high dietary overlap (0.82) indicating potential exploitative or interference competition. Their diet composition, however, varied significantly based on their consumption of wild and domestic prey. Limitation in data precludes predicting direction and outcome of inter-specific interactions between these predators. Our findings suggest a high rate of negative interaction with humans in the region and plausibly retaliatory killings of these imperilled predators. To ensure the sustained survival of these two apex carnivores, conservation measures should enhance populations of their wild prey species while reducing livestock losses of the local community through preventive and mitigative interventions.

scholarly journals Are eucalypts Brazil's friend or foe? An entomological viewpoint

1999 ◽  
Vol 28 (2) ◽  
pp. 185-200 ◽  
Author(s):  
Jonathan D. Majer ◽  
Harry F. Recher
Keyword(s):  
Conservation Status ◽  
Physical Structure ◽  
Eucalyptus Species ◽  
Native Forest ◽  
Native Forests ◽  
Eucalypt Plantations ◽  
Pest Outbreaks ◽  
Flora Of South America ◽  
Leaf Cutting ◽  
Forest Arthropods

Vast areas of Brazil are being planted to Eucalyptus in order to provide renewable sources of timber, charcoal and cellulose. Although the rapid growth and productivity of various Eucalyptus species undoubtedly relaxes the pressure on logging of native forests, there are ecological costs. Firstly, some eucalypt species are vulnerable to pest outbreaks. A large number of native Lepidoptera, Coleoptera and leaf-cutting ants (Atta spp.), some of which have become pests, have been found on eucalypts growing in Brazil. Probably, the diverse myrtaceous flora of South America supports a fauna that can adapt to the introduced Eucalyptus species. Secondly, the leaf litter produced under Eucalyptus plantations differs substantially from that of native forests both in terms of its physical structure and chemistry, posing a range of problems for the native decomposer fauna. If microarthropod diversity is reduced, nutrient cycling could be impeded under eucalypt plantations. Thirdly, native forest canopies support a massive diversity and biomass of arthropods on which many birds, reptiles and mammals depend for food. The evidence is that invertebrate biomass and diversity are greatly reduced in the canopies of exotic eucalypt plantations. This, in turn, reduces the food-base on which forest arthropods and other animals depend, and hence their conservation status. This paper reviews the evidence for adverse ecological effects in Brazilian eucalypt plantations and suggests ways in which Brazil might meet its forestry needs, while conserving forest invertebrates and the vertebrates that depend on them.

Short-term effects of prescribed burning on phosphorus availability in a suburban native forest of subtropical Australia

2013 ◽  
Vol 13 (5) ◽  
pp. 869-876 ◽  
Author(s):  
Wenjuan Huang ◽  
Zhihong Xu ◽  
Chengrong Chen ◽  
Guoyi Zhou ◽  
Juxiu Liu ◽  
...  
Keyword(s):  
Prescribed Burning ◽  
Phosphorus Availability ◽  
Native Forest ◽  
Short Term ◽  
Subtropical Australia ◽  
Short Term Effects

Assessment of N2 fixation by understorey acacias in recurrently burnt eucalypt forests of subtropical Australia using 15N isotope dilution techniques

2000 ◽  
Vol 30 (1) ◽  
pp. 112-121 ◽  
Author(s):  
Danilo F Guinto ◽  
Zhihong Xu ◽  
Alan PN House ◽  
Paul G Saffigna
Keyword(s):  
Isotope Dilution ◽  
Forest Sites ◽  
Whole Plant ◽  
Sclerophyll Forest ◽  
Burnt Soil ◽  
Reference Plants ◽  
N Enrichment ◽  
Eucalypt Forests ◽  
N Natural Abundance ◽  
Subtropical Australia

The N2 fixation by understorey acacias in repeatedly burnt dry and wet sclerophyll forest sites in subtropical Australia was assessed using 15N isotope dilution techniques. In the first study, aboveground parts of established acacias and nonlegume reference plants at the two sites were collected from plots subjected to varying fire frequencies for measurements of 15N natural abundance (<$Q150E00000010446D80BFFEFF88A45505A9A1C8282ADCC6210090483DA6ED4F658F80>15N). The <$Q150E00000010446D80BFFEFF88A45505A9A1C8282ADCC6210090483DA6ED4F658F80>15N values of acacias and nonlegumes were similar, and substantial variation in these <$Q150E00000010446D80BFFEFF88A45505A9A1C8282ADCC6210090483DA6ED4F658F80>15N values precluded any evaluation of N2 fixation. In the second study, 15N enrichment method was used to examine N2 fixation of acacia seedlings grown for 5 months in glasshouse pots of top 10-cm soils collected from the fire plots at the two sites. In Acacia leiocalyx (Domin) Pedley at the dry site, whole plant percent N derived from the atmosphere (%Ndfa) was 25% in unburnt soil, 66% in periodically burnt soil, and 42% in annually burnt soil (referenceAlphitonia excelsa (Cunn. ex Fenzl) Reisseck ex Benth.), compared with 33, 69, and 66%, respectively (reference Corymbia variegata (Hook.) K.D. Hill & L.A.S. Johnson). In Acacia oshanesii F. Muell. & Maiden at the wet site, whole plant %Ndfa was 9% in unburnt soil, 41% in quadrennially burnt soil, and 50% in biennially burnt soil (reference Dodonaea triquetra Andr.), compared with -4, 26, and 55%, respectively (reference Eucalyptus pilularis Sm.).

scholarly journals Forest transitions: a new conceptual scheme

2017 ◽  
Vol 72 (4) ◽  
pp. 465-474 ◽  
Author(s):  
Christian A. Kull
Keyword(s):  
Forest Cover ◽  
Forest Recovery ◽  
Tree Cover ◽  
Native Forest ◽  
Heuristic Model ◽  
Forest Change ◽  
Ecological Processes ◽  
Political Processes ◽  
Political Effect ◽  
Forest Transitions

Abstract. Forest transitions have recently received much attention, particularly in the hope that the historical transitions from net deforestation to forest recovery documented in several temperate countries might be reproduced in tropical countries. The analysis of forest transitions, however, has struggled with questions of forest definition and has at times focussed purely on tree cover, irrespective of tree types (e.g. native forest or exotic plantations). Furthermore, it has paid little attention to how categories and definitions of forest are used to political effect or shape how forest change is viewed. In this paper, I propose a new heuristic model to address these lacunae, building on a conception of forests as distinct socio-ecological relationships between people, trees, and other actors that maintain and threaten the forest. The model draws on selected work in the forest transition, land change science, and critical social science literatures. It explicitly forces analysts to see forests as much more than a land cover statistic, particularly as it internalizes consideration of forest characteristics and the differential ways in which forests are produced and thought about. The new heuristic model distinguishes between four component forest transitions: transitions in quantitative forest cover (FT1); in characteristics like species composition or density (FT2); in the ecological, socio-economic, and political processes and relationships that constitute particular forests (FT3); and in forest ideologies, discourses, and stories (FT4). The four are interlinked; the third category emerges as the linchpin. An analysis of forest transformations requires attention to diverse social and ecological processes, to power-laden official categories and classifications, and to the discourses and tropes by which people interpret these changes. Diverse examples are used to illustrate the model components and highlight the utility of considering the four categories of forest transitions.

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