Planning for the recovery of Lake Toolibin,Western Australia

Lake Toolibin, an intermittently flooded freshwater wetland in the southwest of Western Australia, is threatened by salinization due to extensive clearing within its catchment. The lake is a Wetland of International Importance under the Ramsar Convention because of the extensive stands of trees on the lake bed and its significance as a waterbird breeding site. Past research and monitoring have identified the causes of wetland vegetation and water quality decline and this information has been used to design a Recovery Plan for the lake. The plan is currently in the early stages of implementation and includes both short-term engineering measures to reduce salinity within the lake and long-term rehabilitation measures within the catchment. Community involvement in the recovery process is an integral part of the plan and ensures that recovery of the lake remains as the focus for ongoing catchment rehabilitation.     

Ecosystem remediation in radioactively polluted areas: the Chernobyl experience

The ecosystems of Chernobyl nuclear accident zone, having been deeply transformed by normal long-term agricultural and forestry activity, have been damaged by irradiation after the nuclear accident of 1986 and then influenced by post-accident countermeasures. Ecosystem remediation is being undertaken in this area, including maintenance of the forests, artificial afforestation, and processes of spontaneous self-restoration of the natural coenoses. Both natural and artificial remediation of the landscapes and ecosystems at the abandoned territory improves their capacity to retain radionuclides and their ability to stabilise the processes of redistribution of radionuclides and their spread in the environment. The Chernobyl zone is a territory of great importance for studying ecosystem remediation processes and elaborating on ecological engineering technologies to correct serious environmental problems arising from radionuclides release.     

黄土高原不同生长阶段油松人工林土壤微生物生物量碳的变化及其影响因素

以撂荒地为对照,油松人工幼龄林(13～15 a)、中龄林(25～27 a)和成熟林(41～43 a)为研究对象,分析了黄土高原典型油松人工林不同生长阶段土壤微生物生物量碳的变化特征及其影响因素.结果表明: 油松幼龄林、中龄林和成熟林土壤微生物生物量碳分别为93.08、122.64和191.34 mg·kg^-1,随发育阶段呈显著增加趋势,且显著高于撂荒地(42.93 mg·kg^-1).土壤微生物生物量碳随土层深度呈逐渐降低的趋势,在0～20 cm土层油松幼龄林、中龄林和成熟林较撂荒地分别提高了134.2%、221.7%和375.7%,在20～40 cm土层分别提高了101.3%、164.3%和337.5%,在40～60 cm土层分别提高了103.1%、146.2%和303.0%.油松胸径、高度、根系生物量以及枯落物的厚度、生物量、全氮含量与土壤微生物生物量碳呈显著正相关;土壤有机碳、全氮含量及土壤含水量与土壤微生物生物量碳呈显著正相关.主成分分析表明,油松根系生物量、枯落物生物量和土壤有机碳含量是影响黄土高原油松人工林微生物特征的主要因子.油松生长过程中,枯落物和根系凋落物显著影响了土壤有机碳含量,提高了土壤微生物生物量碳.     

The effect of targeted high‐threat weed control on wet forest understorey vegetation in the Central Highlands region,Victoria

The effective control of highly invasive weeds in Australia is an important conservation management action. In this study, we monitored the outcome of herbicide control on high‐threat weeds in the wet forests of the Central Highlands of Victoria. Twenty‐two control (no weed control) and 32 treatment (weed control) plots were surveyed annually over 24 months. Initial results show that weed cover and frequency decreased substantially in response to weed control; however, it is too early to determine the response of native species. We recommend that herbicide control and the associated monitoring programme be continued, and depending on the outcomes, data should be used to develop a more integrated management strategy.     

The role of natural regeneration to ecosystem services provision and habitat availability: a case study in the Brazilian Atlantic Forest

Natural regeneration provides multiple benefits to nature and human societies, and can play a major role in global and national restoration targets. However, these benefits are context specific and impacted by both biophysical and socioeconomic heterogeneity across landscapes. Here, we investigate the benefits of natural regeneration for climate change mitigation, sediment retention and biodiversity conservation in a spatially explicit way at very high resolution for a region within the global biodiversity hotspot of the Atlantic Forest. We classified current land‐use cover in the region and simulated a natural regeneration scenario in abandoned pasturelands, areas where potential conflicts with agricultural production would be minimized and where some early stage regeneration is already occurring. We then modeled changes in biophysical functions for climate change mitigation and sediment retention, and performed an economic valuation of both ecosystem services. We also modeled how land‐use changes affect habitat availability for species. We found that natural regeneration can provide significant ecological and social benefits. Economic values of climate change mitigation and sediment retention alone could completely compensate for the opportunity costs of agricultural production over 20 yr. Habitat availability is improved for three species with different dispersal abilities, although by different magnitudes. Improving the understanding of how costs and benefits of natural regeneration are distributed can be useful to design incentive structures that bring farmers’ decision making more in line with societal benefits. This alignment is crucial for natural regeneration to fulfill its potential as a large‐scale solution for pressing local and global environmental challenges.     

Ecological outcomes and livelihood benefits of community‐managed agroforests and second growth forests in Southeast Brazil

The Forest and Landscape Restoration movement has emerged as an approach to reconcile biodiversity conservation, ecosystem services provisioning and human well‐being in degraded landscapes, but little is known so far about the potential of different reforestation methods to achieve these objectives. Based on this gap, we assessed the ecological outcomes and local livelihood benefits of community‐managed agroforests and second growth forests to assist natural regeneration in the coastal Atlantic Forest of Brazil. We investigated and compared agroforests and secondary forests according to their structure and floristic composition in 51 circular plots of 314 m², their role in supporting local livelihoods (45 semi‐structured interviews) and the use and cultural importance of plant species (61 interviews). Agroforests and, more remarkably, managed secondary forests (1) re‐established a well‐developed forest structure, with a higher density of tree‐sized individuals and similar basal area compared to nearby old growth forests; (2) were composed by a rich array of native species, including five threatened species, but had lower species richness than old growth remnants; and (3) improved local livelihoods by supplying market valuable and culturally important plants, including 231 native ethnospecies. Overall, local production systems showed remarkable potential to engage smallholders of developing tropical countries in Forest and Landscape Restoration and contribute to achieve its overall goals. We advocate the promotion of these systems as effective Forest and Landscape Restoration approaches in multi‐scale programs and policies.     

Scope for genetic rescue of an endangered subspecies though re‐establishing natural gene flow with another subspecies

Genetic diversity is positively linked to the viability and evolutionary potential of species but is often compromised in threatened taxa. Genetic rescue by gene flow from a more diverse or differentiated source population of the same species can be an effective strategy for alleviating inbreeding depression and boosting evolutionary potential. The helmeted honeyeater Lichenostomus melanops cassidix is a critically endangered subspecies of the common yellow‐tufted honeyeater. Cassidix has declined to a single wild population of ~130 birds, despite being subject to intensive population management over recent decades. We assessed changes in microsatellite diversity in cassidix over the last four decades and used population viability analysis to explore whether genetic rescue through hybridization with the neighbouring Lichenostomus melanops gippslandicus subspecies constitutes a viable conservation strategy. The contemporary cassidix population is characterized by low genetic diversity and effective population size (N_e < 50), suggesting it is vulnerable to inbreeding depression and will have limited capacity to evolve to changing environments. We find that gene flow from gippslandicus to cassidix has declined substantially relative to pre‐1990 levels and argue that natural levels of gene flow between the two subspecies should be restored. Allowing gene flow (~4 migrants per generation) from gippslandicus into cassidix (i.e. genetic rescue), in combination with continued annual release of captive‐bred cassidix (i.e. demographic rescue), should lead to positive demographic and genetic outcomes. Although we consider the risk of outbreeding depression to be low, we recommend that genetic rescue be managed within the context of the captive breeding programme, with monitoring of outcomes.