Plantation forests and biodiversity conservation

There are five key reasons why biodiversity conservation should be considered a part of plantation management. (1) The plantation estate is large, and balancing various land management values with wood and pulp production is important when extensive areas of land are involved. (2) The locations and management of new plantations will affect the biota that currently exist in such landscapes. (3) Maintaining some elements of biodiversity within plantations can have benefits for stand productivity and the maintenance of key ecosystem processes such as pest control. (4) The retention (or loss) of biota in plantations is relevant to the formulation of ecological standards and the certification of plantations in many parts of the world. (5) Plantation forestry has a narrow and intensive management focus on producing a forest crop for a limited array of purposes. It will not meet future societal demands for a range of outputs from plantations (in addition to wood and pulp supply), and will not be congruent with the principles of ecological sustainability. This paper briefly reviews the biodiversity conservation values of Australian plantation s. It shows that almost all work in Australian plantations, whether conifer or eucalypt, highlights the importance of landscape heterogeneity and stand structural complexity for enhancing biodiversity. Management of plantations to promote landscape heterogeneity and stand structural complexity and enhance the conservation of biodiversity will, in many cases, involve tradeoffs that will affect wood and pulp production. The extent to which this occurs will depend on the objectives of plantation management and how far they extend towards the more complex plantation forestry models that incorporate social and environmental values. We argue that the widespread adoption of plantation forestry that leads to homogenous stands of extensive monocultures will risk re-creating the array of negative environmental outcomes that have been associated with agriculture in many parts of Australia

Plantations, not farmlands, cause biotic homogenisation of ground-active beetles in South-Eastern Australia

Following landscape change, species invasions and extinctions may lead to biotic homogenisation, resulting in increased taxonomic and functional similarity between previously distinct biotas. Biotic homogenisation is more likely to occur in landscapes where the matrix contrasts strongly with native vegetation patches. To test this, we examined the distribution of ground-active beetles in a landscape of remnant Eucalyptus open woodland patches where large areas of lower contrast matrix (farmland) are being transformed to high-contrast pine plantations in south-eastern Australia. We sampled beetles from 30 sites including six replicates of five categories; (1) remnants adjacent to farmland, (2) remnants adjacent to plantation, (3) farmland, (4) plantation, and, (5) remnants between pine plantation and farmland. Community composition in the pine matrix was similar to native patches embedded in pine (ANOSIM, Global R=. 0.49, P<. 0.000), which we suggest is due to biotic homogenisation. Remnant patches with edges of both farmland and pine plantation did not represent an intermediate community composition between patches surrounded by either matrix type, but rather a unique habitat with unique species. Farmland supported the greatest number of individuals (. F=. 9.049, df. =. 25, P<. 0.000) and species (. F=. 5.875, df. =. 25, P=. 0.002), even compared to native remnant patches. Our results suggest that matrix transformations can reduce species richness and homogenise within-patch populations. This may increase the risk of species declines in fragmented landscapes where plantations are not only replacing native vegetation patches, but also other matrix types that may better support biodiversity. Our findings are particularly concerning given expanding plantation establishment worldwide

Modelling the impacts of wildfire on the viability of metapopulations of the endangered Australian species of arboreal marsupial, Leadbeater's Possum

Catastrophic events such as intensive wildfires have a major effect on the dynamics of some wildlife populations. In this investigation, the computer package ALEX (Analysis of the Likelihood of EXtinction), was used to simulate the impacts of wildfires on the persistence of metapopulations of the endangered species Leadbeater's possum (Gymnobelideus leadbeateri) which is restricted to the montane ash forests of the Central Highlands of Victoria. A range of scenarios was examined. First, the response of G. leadbeateri to tires in hypothetical patches of old growth forest of varying size was modelled. Metapopulation dynamics were then modelled in four existing forest management areas: the O'Shannassy Water Catchment and the Steavenson, Ada and Murrindindi Forest Blocks using GIS-derived forest inventory data on complex spatial arrangements of potentially suitable old growth habitat patches. The impacts of different fire frequencies and the proportion of forest area that was burnt in the Steavenson Forest Block and the O'Shannassy Water Catchment were examined. Finally, the combined impacts of both wildfires and post-fire salvage logging operations on the persistence of populations of G. leadbeateri were assessed. Our analyses indicated that, even in the absence of wildfires, populations of G. leadbeateri are very susceptible to extinction within single isolated habitat patches of 20 ha or less. The probability of persistence approached 100% in patches of 250 ha. The incorporation of the effects of wildfire was predicted to have a major negative impact on isolated populations of G. leadbeateri. In these cases, the probability of population extinction remained above 60%, even when a single patch of 1200 ha of old growth forest was modelled. In the absence of wildfires, there was a low probability of extinction of G. leadbeateri in the O'Shannassy Water Catchment where very large patches of old growth forest presently exist. The risk of extinction of the species was significantly higher in the Murrindindi and Ada Forest Blocks where there are lower total areas of, and significantly smaller, suitable habitat patches. Wildfires resulted in an increase in the predicted probability of metapopulation extinction in the four areas that were targeted for study. An investigation of the Steavenson Forest Block and the O'Shannassy Water Catchment revealed that the predicted values for the probability of extinction were sensitive to inter-relationships between the frequency of fires and the proportion of habitat patches that were burnt during a given fire event. The probability of extinction of G. leadbeateri was predicted to be lowest when there were frequent fires that burnt only relatively small areas of a given forest block. Conversely, the results of our analyses suggested that populations of the species are vulnerable to infrequent but intensive conflagrations that burnt a large proportion of the forest. The results of the suite of analyses completed in this study suggest hat four management strategies will be important for the long-term conservation of G. leadbeateri. (1) Attempts to suppress wildfires should be maintained as even the largest remaining areas of old growth forest may be susceptible to being burnt by repeated widespread wildfires that could result in localised and/or global extinction of the species. (2) Because the probability of population persistence is greatest in those areas that support more extensive stands of old growth forest, it will be important to grow relatively large patches of existing regrowth forest (over 50 ha) through to ecological maturity. This will be particularly important in some wood production forest blocks where there are only limited areas of old growth forest. (3) Patches that are set aside for the conservation of G. leadbeateri should be spatially separated to minimise the risk that all of the reserved areas in a region are destroyed in a single major fire event. (4) Salvage logging operations should be excluded from stands of old growth forest and reserved areas that are burnt in a wildfire. This is because such activities can have a major negative impact of the development of suitable habitat for G. leadbeateri

Substantial and increasing global losses of timber-producing forest due to wildfires

One-third of global forest is harvested for timber, generating ~US$1.5 trillion annually. High-severity wildfires threaten this timber production. Here we combine global maps of logging activity and stand-replacing wildfires to assess how much timber-producing forest has been lost to wildfire this century, and quantify spatio-temporal changes in annual area lost. Between 2001 and 2021, 18.5–24.7 million hectares of timber-producing forest—an area the size of Great Britain—experienced stand-replacing wildfires, with extensive burning in the western USA and Canada, Siberian Russia, Brazil and Australia. Annual burned area increased significantly throughout the twenty-first century, pointing to substantial wildfire-driven timber losses under increasingly severe climate change. To meet future timber demand, producers must adopt new management strategies and emerging technologies to combat the increasing threat of wildfires

The Conservation Of Arboreal Marsupials In The Montane Ash Forests Of The Central Highlands Of Victoria, South-Eastern Australia - VII. Modelling The Persistence Of Leadbeater's Possum In Response To Modified Timber Harvesting Practices

A computer model for Population Viability Analysis (PVA) was used to simulate the relationship between the persistence of populations of the endangered species, Leadbeater's possum, Gymnobelideus leadbeateri and the implementation of a range of possible modified timber harvesting practices in two wood production blocks within the montane ash forests of the central highlands of Victoria, south-eastern Australia. The results of our analyses revealed that under the existing conservation strategies there was a high probability of extinction over the next 150 years in both blocks. Given that timber production areas comprise more than 75% of the distribution of G. leadbeateri, our findings highlight a need for additional conservation measures to enhance the survival prospects of the species. The range of upgraded conservation strategies that were examined included (1) extending the rotation time between logging operations; (2) modifying silvicultural practices to increase the amount of forest retained within each harvested coupe; and (3) permanently withdrawing areas from wood production. All of each of these approaches were found significantly to reduce the probability of extinction of populations of G. leadbeateri. However, when the relative merits of the various strategies were compared, the permanent withdrawal of potential logging coupes from timber harvesting was predicted to be the most efficient approach. Importantly, this strategy would have a number of practical advantages including that it overcomes both (1) the logistic difficulties of ensuring the long-term survival of retained trees within logged areas; and (2) human safety issues arising from implementing modified silvicultural practices. This practical application of PVA to compare the merits of different potential management options has provided new information that will enhance present efforts to conserve G. leadbeateri in wood production areas

Effects of large-scale heathland management on thermal regimes and predation on adders Vipera berus

Management prescriptions for species of conservation concern often focus on creating appropriate habitat conditions, but the spatial scales over which these actions are applied can potentially impact their success. In Northwestern Europe, preventing further loss of lowland heathland through successional changes often involves the mechanical removal of vegetation, creating large blocks of open homogenous habitat. We investigate the influence of this broad-scale habitat management on a heathland specialist, the adder Vipera berus. By deploying temperature loggers and Plasticine adder models in heathland areas with and without complex vegetation cover, we show that (1) cleared areas lack both the temperature variation adders need to thermoregulate effectively and suitable refuges from dangerously high summer temperatures, and (2) attacks by dogs and trampling by grazing livestock are significantly more frequent in cleared areas and closer to footpaths. Habitat management strategies that retain some structural complexity of vegetation within cleared areas, and diverting footpaths away from cleared areas and/or strategic placement of barrier hedging around these areas could potentially reduce the exposure of adders to high predation risk and thermal extremes

A major shift to the retention approach for forestry can help resolve some global forest sustainability issues

Approximately 85% of the global forest estate is neither formally protected nor in areas dedicated to intensive wood production (e.g., plantations). Given the spatial extent of unprotected forests, finding management approaches that will sustain their multiple environmental, economic, and cultural values and prevent their conversion to other uses is imperative. The major global challenge of native forest management is further demonstrated by ongoing steep declines in forest biodiversity and carbon stocks. Here, we suggest that an essential part of such management—supplementing the protection of large reserves and sensitive areas within forest landscapes (e.g., aquatic features)—is the adoption of the retention approach in forests where logging occurs. This ecological approach to harvesting provides for permanent retention of important selected structures (e.g., trees and decayed logs) to provide for continuity of ecosystem structure, function, and species composition in the postharvest forest. The retention approach supports the integration of environmental, economic, and cultural values and is broadly applicable to tropical, temperate, and boreal forests, adaptable to different management objectives, and appropriate in different societal settings. The widespread adoption of the retention approach would be one of the most significant changes in management practice since the onset of modern high-yield forestry.Fil: Lindenmayer, D.B.. The Australian National University,; AustraliaFil: Franklin, J.F.. University of Washington; Estados UnidosFil: Lõhmus, A.. University of Tartu; EstoniaFil: Baker, S.C.. University of Tasmania; AustraliaFil: Bauhus, J.. Albert Ludwigs University of Freiburg; AlemaniaFil: Beese, W.. University of Vancouver; CanadáFil: Brodie, A.. No especifíca;Fil: Kiehl, B.. Swedish University of Agricultural Sciences; SueciaFil: Kouki, J.. University of Eastern Finland; FinlandiaFil: Martínez Pastur, Guillermo José. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Austral de Investigaciones Científicas; ArgentinaFil: Messier, C.. Université du Québec a Montreal; CanadáFil: Neyland, M.. University of Tasmania; AustraliaFil: Palik, B.. No especifíca;Fil: Sverdrup Thygeson, A.. Norwegian University of Life Sciences; NoruegaFil: Volney, J.. Canadian Forest Service; CanadáFil: Wayne, A.. No especifíca;Fil: Gustafsson, L.. Swedish University of Agricultural Sciences; Sueci

Modelling the probability of microhabitat formation on trees using cross-sectional data

The rate of TreM formation per unit diameter growth was modelled as a function of tree diameter at breast height (DBH), and the model was calibrated considering cross-sectional observations TreMs on trees of different sizes. The model predicted realistic TreM formation rates at the tree and stand levels in forests dominated by Abies alba and Fagus sylvatica. This approach opens new perspectives to the analysis of forest biodiversity conservation strategies

Impacts of salvage logging on biodiversity: A meta-analysis

Logging to "salvage" economic returns from forests affected by natural disturbances has become increasingly prevalent globally. Despite potential negative effects on biodiversity, salvage logging is often conducted, even in areas otherwise excluded from logging and reserved for nature conservation, inter alia because strategic priorities for post-disturbance management are widely lacking. A review of the existing literature revealed that most studies investigating the effects of salvage logging on biodiversity have been conducted less than 5 years following natural disturbances, and focused on non-saproxylic organisms. A meta-analysis across 24 species groups revealed that salvage logging significantly decreases numbers of species of eight taxonomic groups. Richness of dead wood dependent taxa (i.e. saproxylic organisms) decreased more strongly than richness of non-saproxylic taxa. In contrast, taxonomic groups typically associated with open habitats increased in the number of species after salvage logging. By analysing 134 original species abundance matrices, we demonstrate that salvage logging significantly alters community composition in 7 of 17 species groups, particularly affecting saproxylic assemblages. Synthesis and applications. Our results suggest that salvage logging is not consistent with the management objectives of protected areas. Substantial changes, such as the retention of dead wood in naturally disturbed forests, are needed to support biodiversity. Future research should investigate the amount and spatio-temporal distribution of retained dead wood needed to maintain all components of biodiversity

Can forest management based on natural disturbances maintain ecological resilience?

Given the increasingly global stresses on forests, many ecologists argue that managers must maintain ecological resilience: the capacity of ecosystems to absorb disturbances without undergoing fundamental change. In this review we ask: Can the emerging paradigm of natural-disturbance-based management (NDBM) maintain ecological resilience in managed forests? Applying resilience theory requires careful articulation of the ecosystem state under consideration, the disturbances and stresses that affect the persistence of possible alternative states, and the spatial and temporal scales of management relevance. Implementing NDBM while maintaining resilience means recognizing that (i) biodiversity is important for long-term ecosystem persistence, (ii) natural disturbances play a critical role as a generator of structural and compositional heterogeneity at multiple scales, and (iii) traditional management tends to produce forests more homogeneous than those disturbed naturally and increases the likelihood of unexpected catastrophic change by constraining variation of key environmental processes. NDBM may maintain resilience if silvicultural strategies retain the structures and processes that perpetuate desired states while reducing those that enhance resilience of undesirable states. Such strategies require an understanding of harvesting impacts on slow ecosystem processes, such as seed-bank or nutrient dynamics, which in the long term can lead to ecological surprises by altering the forest's capacity to reorganize after disturbance