• Energy Research

Forests are critical for the world's biodiversity, the regulation of the Earth's climate, and the provision of goods and services for humans. This review focuses on four broad topics: (1) key processes threatening forest biodiversity; (2) broad strategies for mitigating threatening processes; (3) climate change and forest biodiversity; and, (4) plantations and biodiversity. How key issues within these broad topics are addressed will have profound effects on forest biodiversity and the Earth's climate. A significant global problem for biodiversity conservation is the conversion of natural forests to other land uses, both in developing and developed nations; ways must be urgently identified to halt forest conversion. When forests are logged for timber or pulpwood and then regenerated, impacts on biodiversity are harder to quantify than when forests are converted to other land uses. Hence, the effectiveness of efforts to mitigate such impacts (where they occur) is frequently not well known. Climate change may result in substantial changes to forest ecosystems, and its effects may interact in additive or cumulative ways with other human disturbances in forests, although work on such combinations of impacts is in its infancy. The establishment of plantations of trees is frequently proposed to sequester large amounts of carbon and/or produce biofuels to mitigate the climate‐change effects. However, there is potential for perverse outcomes, such as biodiversity loss where plantation establishment is narrowly focused and other environmental values are ignored.

Summary  Australia’s temperate woodlands are environments of cultural and ecological importance and significant repositories of Australia’s biodiversity. Despite this, they have been heavily cleared, much remaining vegetation is in poor condition and many species of plants and animals are threatened. Here, we provide a brief overview of key issues relating to the ecology, management and policy directions for temperate woodlands, by identifying and discussing ten themes. When addressing issues relating to the conservation and management of temperate woodlands, spatial scale is very important, as are the needs for a temporal perspective and a complementary understanding of pattern and process. The extent of landscape change in many woodland environments means that woodland patches, linear networks and paddock trees are critical elements, and that there can be pervasive effects from ‘problem’ native species such as the Noisy Miner (Manorina melanocephala). These consequences of landscape change highlight the challenge to undertake active management and restoration as well as effective monitoring and long‐term data collection. In developing approaches for conservation and management of temperate woodlands, it is essential to move our thinking beyond reserves to woodland conservation and management on private land, and recognise the criticality of cross‐disciplinary linkages. We conclude by identifying some emerging issues in woodland conservation and management. These include the need to further develop non‐traditional approaches to conservation particularly off‐reserve management; the value of documenting approaches and programmes that demonstrably lead to effective change; new lessons that can be learned from intact examples of temperate woodlands; and the need to recognise how climate change and human population growth will interact with conservation and management of temperate woodlands in future decades.

There is growing evidence around the world of serious decline in biodiversity requiring urgent application of precautionary risk management. A better regulatory regime for precautionary management of long-term risk is now an urgent priority. This article addresses the prioritization of long-term risk management by examining risk management of ecosystems that may be experiencing hidden collapse. Hidden collapse refers to the existence of environmental indicators indicative of future collapse of forests, even though the forest appears intact and not at risk of ecosystem collapse. Professor David Lindenmayer and Dr Chloe Sato (Lindenmayer) first identified hidden collapse in 2018 in Mountain Ash forests of Victoria, Australia. The risk of hidden collapse represents a long-term environmental threat and is a potential trigger for application of the precautionary principle (principle). Implicit in hidden collapse are two preconditions for application of the principle; the risk of a serious or irreversible environmental threat, and the existence of scientific uncertainty about the nature of the risk. Despite hidden collapse satisfying these essential preconditions for applying the principle, decision makers did not apply it in respect hidden collapse of Mountain Ash forests in Victoria. This article considers the current status of the principle in regulation and how it can be adjusted to address long term environmental risk.

AbstractAim  Insect biodiversity is often positively associated with habitat heterogeneity. However, this relationship depends on spatial scale, with most studies focused on differences between habitats at large scales with a variety of forest tree species. We examined fine‐scale heterogeneity in ground‐dwelling beetle assemblages under co‐occurring trees in the same subgenus: Eucalyptus melliodora A. Cunn. ex Schauer and E. blakelyi Maiden (Myrtaceae).Location  Critically endangered grassy woodland near Canberra, south‐eastern Australia.Methods  We used pitfall traps and Tullgren funnels to sample ground‐dwelling beetles from the litter environment under 47 trees, and examined differences in diversity and composition at spatial scales ranging from 100 to 1000 m.Results  Beetle assemblages under the two tree species had distinctive differences in diversity and composition. We found that E. melliodora supported a higher richness and abundance of beetles, but had higher compositional similarity among samples. In contrast, E. blakelyi had a lower abundance and species richness of beetles, but more variability in species composition among samples.Main conclusions  Our study shows that heterogeneity in litter habitat under co‐occurring and closely related eucalypt species can influence beetle assemblages at spatial scales of just hundreds of metres. The differential contribution to fine‐scale alpha and beta diversity by each eucalypt can be exploited for conservation purposes by ensuring an appropriate mix of the two species in the temperate woodlands where they co‐occur. This would help not only to maximize biodiversity at landscape scales, but also to maintain heterogeneity in species richness, trophic function and biomass at fine spatial scales.

From analysis of published global site biomass data ( n = 136) from primary forests, we discovered ( i ) the world's highest known total biomass carbon density (living plus dead) of 1,867 tonnes carbon per ha (average value from 13 sites) occurs in Australian temperate moist Eucalyptus regnans forests, and ( ii ) average values of the global site biomass data were higher for sampled temperate moist forests ( n = 44) than for sampled tropical ( n = 36) and boreal ( n = 52) forests ( n is number of sites per forest biome). Spatially averaged Intergovernmental Panel on Climate Change biome default values are lower than our average site values for temperate moist forests, because the temperate biome contains a diversity of forest ecosystem types that support a range of mature carbon stocks or have a long land-use history with reduced carbon stocks. We describe a framework for identifying forests important for carbon storage based on the factors that account for high biomass carbon densities, including ( i ) relatively cool temperatures and moderately high precipitation producing rates of fast growth but slow decomposition, and ( ii ) older forests that are often multiaged and multilayered and have experienced minimal human disturbance. Our results are relevant to negotiations under the United Nations Framework Convention on Climate Change regarding forest conservation, management, and restoration. Conserving forests with large stocks of biomass from deforestation and degradation avoids significant carbon emissions to the atmosphere, irrespective of the source country, and should be among allowable mitigation activities. Similarly, management that allows restoration of a forest's carbon sequestration potential also should be recognized.

La certification a fait progresser les efforts visant à accroître la durabilité environnementale de l'agriculture du palmier à huile. Cependant, il y a peu de consensus parmi les parties prenantes sur le type de système agricole à utiliser pour améliorer la durabilité environnementale de la chaîne d'approvisionnement en huile de palme. La replantation de palmiers à huile a augmenté en raison des engagements pris pour réduire la déforestation et de la nécessité de remplacer les plantations vieillissantes. Au cours des 10 à 20 prochaines années, environ 24 millions d'hectares de grandes plantations industrielles et de petites exploitations seront replantés sous les tropiques. Les preuves provenant d'études précédentes indiquent qu'il existe des impacts négatifs de la replantation de palmiers à huile à grande échelle sur la biodiversité. Ici, nous avons comparé la taille des replantations dans les petites exploitations et les grandes plantations industrielles à l'aide d'images satellites open source. Nous avons ensuite fait des prédictions sur leurs effets environnementaux possibles de la replantation de palmiers à huile. À l'aide de Google Earth Pro, nous avons calculé cinq mesures de paysage sur 865 champs replantés : taille, périmètre, indice de forme, distance minimale et maximale entre un centroïde d'un champ planté et la limite du champ. Ces mesures représentent très probablement la façon dont la couverture spatiale affecte la distribution et les mouvements des animaux dans les paysages de production de palmier à huile. En outre, 52 ornithologues locaux ont été interrogés sur leurs perceptions des impacts de la replantation de palmiers à huile sur les oiseaux indigènes. Nous avons constaté que les paramètres du paysage pour la replantation dans les petites exploitations étaient inférieurs à ceux calculés pour les plantations industrielles à grande échelle. La plupart des ornithologues locaux pensaient que la replantation de palmiers à huile dans les plantations industrielles avait un effet plus néfaste sur les espèces d'oiseaux indigènes (21 contre 10 répondants) que la replantation sur les petites exploitations. En outre, les ornithologues locaux ont considéré que la replantation de palmiers à huile sur de petites exploitations était plus neutre (21 contre 29 répondants) et bénéfique (11 contre 12 répondants) pour les oiseaux que la replantation dans des plantations industrielles. Nos résultats suggèrent que les impacts sur la biodiversité de la replantation de palmiers à huile sur les petites exploitations seront moins graves que sur les grandes plantations industrielles. Nous recommandons aux entreprises de plantation d'utiliser des techniques de replantation comparables à celles des petites exploitations. Les résultats rapportés ici peuvent aider les parties prenantes de l'industrie à atténuer les conséquences environnementales négatives des replantations de palmiers à huile sur les terres agricoles et la biodiversité forestière. La certificación ha avanzado en los esfuerzos para aumentar la sostenibilidad ambiental de la agricultura de palma aceitera. Sin embargo, existe poco consenso entre las partes interesadas sobre qué tipo de sistema de cultivo debe emplearse para mejorar la sostenibilidad ambiental de la cadena de suministro de palma aceitera. La replantación de palma aceitera ha aumentado como resultado de los compromisos para reducir la deforestación y la necesidad de reemplazar las plantaciones envejecidas. En los próximos 10–20 años, se replantarán aproximadamente 24 millones de hectáreas de plantaciones industriales a gran escala y pequeñas explotaciones en los trópicos. La evidencia de estudios anteriores indica que hay impactos adversos de la replantación de palma aceitera a gran escala en la biodiversidad. Aquí comparamos el tamaño de la replantación en pequeñas explotaciones y plantaciones industriales a gran escala utilizando imágenes satelitales de código abierto. Luego hicimos predicciones sobre sus posibles efectos ambientales de la replantación de palma aceitera. Usando Google Earth Pro, calculamos cinco métricas de paisaje en 865 campos replantados: tamaño, perímetro, índice de forma, distancia mínima y máxima desde un centroide de un campo plantado hasta el límite del campo. Estas métricas probablemente representan cómo la cobertura espacial afecta la distribución y el movimiento de los animales en los paisajes de producción de palma aceitera. Además, se encuestó a 52 observadores de aves locales sobre sus percepciones de los impactos de la replantación de palma aceitera en aves nativas. Encontramos que las métricas de paisaje para la replantación en pequeñas fincas fueron inferiores a las calculadas para las plantaciones industriales a gran escala. La mayoría de los observadores de aves locales pensaban que la replantación de palma aceitera en plantaciones industriales tenía un mayor efecto perjudicial en las especies de aves nativas (21 frente a 10 encuestados) que la replantación en pequeñas explotaciones. Además, los observadores de aves locales consideraron que la replantación de palma aceitera en pequeñas explotaciones era más neutral (21 frente a 29 encuestados) y beneficiosa (11 frente a 12 encuestados) para las aves que la replantación en plantaciones industriales. Nuestros hallazgos sugieren que los impactos en la biodiversidad de la replantación de palma aceitera en las pequeñas explotaciones serán menos graves que en las plantaciones industriales a gran escala. Recomendamos que las empresas de plantación utilicen técnicas de replantación comparables a las de las pequeñas explotaciones. Los hallazgos informados aquí pueden ayudar a las partes interesadas de la industria a mitigar las consecuencias ambientales negativas de las replantaciones de palma aceitera en las tierras de cultivo y la biodiversidad forestal. Certification has advanced efforts to increase the environmental sustainability of oil palm agriculture. However, there is little consensus among stakeholders on what type of farming system should be employed to enhance the environmental sustainability of the oil palm supply chain. Replanting of oil palm has increased as a result of commitments to reduce deforestation and the need to replace ageing plantations. In the next 10–20 years, ∼ 24 million ha of large-scale industrial plantations and smallholdings will be replanted across the tropics. Evidence from previous studies indicates there are adverse impacts of large-scale oil palm replanting on biodiversity. Here we compared the size of replanting in smallholdings and large-scale industrial plantations using open source satellite images. We then made predictions about their possible environmental effects of oil palm replanting. Using Google Earth Pro, we calculated five landscape metrics at 865 replanted fields: size, perimeter, shape index, minimum and maximum distance from a centroid of a planted field to the boundary of the field. These metrics most likely represent how spatial cover affects animal distribution and movement in oil palm production landscapes. In addition, 52 local birders were polled about their perceptions of impacts of oil palm replanting on native birds. We found that the landscape metrics for replanting in smallholdings were lower than those calculated for large-scale industrial plantations. Most local birders thought that replanting oil palm in industrial plantations had a greater detrimental effect on native bird species (21 versus 10 respondents) than replanting on smallholdings. In addition, local birdwatchers considered replanting oil palm on smallholdings to be more neutral (21 versus 29 respondents) and beneficial (11 versus 12 respondents) for birds than replanting in industrial plantations. Our findings suggest that the biodiversity impacts of oil palm replanting on smallholdings will be less severe than on large-scale industrial plantations. We recommend plantation businesses use replanting techniques comparable to smallholdings. The findings reported here may help industry stakeholders mitigate the negative environmental consequences of oil palm replantings on farmland and forest biodiversity. وقد عزز إصدار الشهادات الجهود المبذولة لزيادة الاستدامة البيئية لزراعة نخيل الزيت. ومع ذلك، هناك إجماع ضئيل بين أصحاب المصلحة على نوع النظام الزراعي الذي ينبغي استخدامه لتعزيز الاستدامة البيئية لسلسلة توريد نخيل الزيت. وزادت إعادة زراعة نخيل الزيت نتيجة للالتزامات بالحد من إزالة الغابات والحاجة إلى استبدال المزارع القديمة. في السنوات العشر إلى العشرين المقبلة، ستتم إعادة زراعة 24 مليون هكتار من المزارع الصناعية واسعة النطاق والممتلكات الصغيرة في جميع أنحاء المناطق الاستوائية. تشير الأدلة المستقاة من الدراسات السابقة إلى وجود آثار ضارة لإعادة زراعة نخيل الزيت على نطاق واسع على التنوع البيولوجي. هنا قارنا حجم إعادة الزراعة في الحيازات الصغيرة والمزارع الصناعية واسعة النطاق باستخدام صور الأقمار الصناعية مفتوحة المصدر. ثم قدمنا تنبؤات حول آثارها البيئية المحتملة لإعادة زراعة نخيل الزيت. باستخدام Google Earth Pro، قمنا بحساب خمسة مقاييس للمناظر الطبيعية عند 865 حقلًا تم إعادة زراعتها: الحجم، المحيط، مؤشر الشكل، المسافة الدنيا والقصوى من مركز الحقل المزروع إلى حدود الحقل. تمثل هذه المقاييس على الأرجح كيفية تأثير الغطاء المكاني على توزيع الحيوانات وحركتها في المناظر الطبيعية لإنتاج نخيل الزيت. بالإضافة إلى ذلك، تم استطلاع رأي 52 من الطيور المحلية حول تصوراتهم لتأثيرات إعادة زراعة نخيل الزيت على الطيور المحلية. وجدنا أن مقاييس المناظر الطبيعية لإعادة الزراعة في الحيازات الصغيرة كانت أقل من تلك المحسوبة للمزارع الصناعية واسعة النطاق. اعتقد معظم الطيور المحليين أن إعادة زراعة نخيل الزيت في المزارع الصناعية كان لها تأثير ضار أكبر على أنواع الطيور المحلية (21 مقابل 10 مجيبين) من إعادة الزراعة على الحيازات الصغيرة. بالإضافة إلى ذلك، اعتبر مراقبو الطيور المحليون أن إعادة زراعة نخيل الزيت في الحيازات الصغيرة أكثر حيادية (21 مقابل 29 مجيباً) ومفيدة (11 مقابل 12 مجيباً) للطيور من إعادة الزراعة في المزارع الصناعية. تشير النتائج التي توصلنا إليها إلى أن تأثيرات التنوع البيولوجي لإعادة زراعة نخيل الزيت على الحيازات الصغيرة ستكون أقل حدة من المزارع الصناعية واسعة النطاق. نوصي شركات المزارع باستخدام تقنيات إعادة الزرع المماثلة للمزارع الصغيرة. قد تساعد النتائج الواردة هنا أصحاب المصلحة في الصناعة على التخفيف من الآثار البيئية السلبية لإعادة زراعة نخيل الزيت على التنوع البيولوجي للأراضي الزراعية والغابات.

Abstract 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.