Tanya G. Bailey

With climate change impacting trees worldwide, enhancing adaptation capacity has become an important goal of provenance translocation strategies for forestry, ecological renovation, and biodiversity conservation. Given that not every species can be studied in detail, it is important to understand the extent to which climate adaptation patterns can be generalised across species, in terms of the selective agents and traits involved. We here compare patterns of genetic-based population (co)variation in leaf economic and hydraulic traits, climate–trait associations, and genomic differentiation of two widespread tree species (Eucalyptus pauciflora and E. ovata). We studied 2-year-old trees growing in a common-garden trial established with progeny from populations of both species, pair-sampled from 22 localities across their overlapping native distribution in Tasmania, Australia. Despite originating from the same climatic gradients, the species differed in their levels of population variance and trait covariance, patterns of population variation within each species were uncorrelated, and the species had different climate–trait associations. Further, the pattern of genomic differentiation among populations was uncorrelated between species, and population differentiation in leaf traits was mostly uncorrelated with genomic differentiation. We discuss hypotheses to explain this decoupling of patterns and propose that the choice of seed provenances for climate-based plantings needs to account for multiple dimensions of climate change unless species-specific information is available.

Fire regimes are changing in several regions of the world. In those regions, some exotic species may be better adapted to new regimes than the native species. This study focused on identifying the microsite characteristics associated with the occurrence of post-fire Eucalyptus globulus regeneration from seeds, outside the species native-range. This information is important in helping to assess the naturalization status of the species, to understand its invasion risk, and to manage wildlings in plantations. To characterize the establishment niche, pairs of microsites (sapling presence/absence) were sampled in four salvage-logged plantations of E. globulus two years after fire (20 pairs/plantation). Microsites of wildlings from three size classes and control microsites were established in one of these plantations (20 quartets) in order to characterize the recruitment niche and to assess ontogenic niche shifts. Two post-fire wildling cohorts were identified. The first emerged just after fire and was abundant. The second emerged after logging and was scarce, probably due to seed limitation. First-cohort wildlings were observed in microsites characterized by a high incidence of fire-related variables (charcoal, ash, increased soil pH and K). The aggregated distribution of these wildlings and their association with other species may indicate the existence of facilitative relationships and/or the exploitation of resource-rich patches. All these factors were relevant for first-cohort persistence and likely also for its establishment and recruitment. Second-cohort wildlings occurred in microsites where salvage-logging disturbance was evident, showing the importance of this disturbance for its emergence. Wildling size diversity was explained by the two recruitment events and by the asymmetrical competition between wildlings and adults. No niche shifts were detected. The high densities of E. globulus wildlings found established in burnt plantations indicated naturalization was in progress. The timing of major recruitment events and the phenology of the species should be considered for monitoring this regeneration and scheduling control interventions, if required.

The Tasmanian Midlands restoration work includes a multi‐faceted educational programme that connects schoolchildren, university students, researchers, artists and the community in the Midlands. Here, we outline this programme and consider its many benefits and challenges through its five years of continued support.

Summary: There is an ongoing search for cost‐effective, practical and successful methods for landscape‐scale restoration required to meet the challenges posed by the United Nations Decade on Restoration 2021–2013. Mechanised cultivation techniques (rip mounding and Wilco spot cultivation), a range of revegetation strategies (dense reafforestation, riparian corridors, vegetation islets and scattered tree plantings) and best horticultural practice were employed to successfully establish extensive areas of local native trees and shrubs in highly altered agricultural landscapes within the Midlands of Tasmania, Australia. This region has been intensely farmed for the last 200 years and is characterised by past failures in native tree plantings. Between 2009 and 2018, 1800 ha were revegetated with a suite of hardy local native species to enhance, buffer and connect native vegetation remnants. These techniques were applied at a landscape scale to create biodiversity corridors that crossed the Midlands. Riparian corridors 100–200 m wide were created along 21 km of riverbank at an average density of 440 stems/ha. Fenced vegetation islets and individually caged scattered trees were established within and surrounding native vegetation remnants, at an average density of 143 stems/ha. Whole paddocks were densely reafforested at up to 800 stems/ha. Despite this, re‐establishing structurally complex and species diverse native vegetation, which can provide habitat for local native animals, proved challenging. In areas highly altered by a long history of farming, repeated interventions and long‐term relationships with landholders will be needed to achieve restoration objectives.

Summary: Direct‐seeding trials in Tasmania tested the effectiveness of five treatments: a clear polymer film removed at three time intervals; insecticide; wetting agent; irrigation; and caging to exclude all mammal herbivores. The most effective treatment in improving early establishment of 15 native species across 2 years and at five sites was the application of the insecticide Bifenthrin to reduce seed predation by ants. The polymer film removed after 10 weeks also improved germination of a range of shrubby but not tree species. However, these early advantages were eroded over time at the first trial site due to damage from herbivores and at subsequent sites due to weed competition and mortality of seedlings over summer. Caging was beneficial to the ongoing persistence of tree and shrub species but also protected weeds. Further work on seed testing and timely weed control is needed.

Summary: We synthesise the findings from 10 years of ecological restoration in the Midlands of Tasmania, Australia, captured in the series of 14 papers in this special issue of Ecological Management and Restoration. The papers illustrate how expertise from disciplines as diverse as law, economics, social sciences, the arts, education, zoology, botany, genetics, climate modelling, agriculture, spatial sciences and fire ecology are necessary to address the complex social, ecological and financial questions that underpin restoration ecology. We highlight the complexity of the task, the multi‐disciplinary and collaborative approach needed, the importance of science to inform restoration practice and the problem of achieving functional connectivity. We also outline steps that need to be taken in the next 10 years. Together, the outcomes and recommendations from these studies provide a template for restoration in similar highly cleared and degraded agricultural landscapes affected by climate change in Australia and internationally.

Summary: The benefits of using remote sensing technologies for informing and monitoring ecological restoration of forests from the community to the individual are presented. At the community level, we link remotely sensed measures of structural complexity with animal behaviour. At the plot level, we monitor the return of vegetation structure and ecosystem services (e.g. carbon sequestration) using data‐rich three‐dimensional point clouds. At the individual‐level, we use high‐resolution images to accurately classify plants to species and provenance and show genetic‐based variation in canopy structural traits. To facilitate the wider use of remote sensing in restoration, we discuss the challenges that remain to be resolved.

Summary: Estimates of dry biomass and carbon sequestration were made for environmental plantings established in the harsh, dry agricultural landscapes of the Midlands of Tasmania. Plantings were designed to provide habitat connectivity for native wildlife. The dry biomass for 6‐year‐old woodland and riparian plantings was estimated to be 4.7 and 9.0 tonnes/ha, respectively. The carbon component of this biomass was estimated to be 2.4 and 4.5 tonnes/ha carbon, equivalent to 8.7 and 16.5 tonnes/ha carbon dioxide (CO₂) sequestered, respectively. These are lower than previous estimates for plantings of the same age in the same landscape. This is largely due to lower planting densities of 200 stems/ha, and 883 stems/ha respectively, for woodland and riparian plantings, relative to comparable plantings (˜1,000 stems/ha). Further, a combination of extreme climatic events during early establishment and high heterogeneity in soil type and landscape position reduced performance in riparian plantings.

Summary: At the dawn of the Anthropocene, with the imminent threat of climate change delivering 3–4°C rise in temperature by the end of the century and biodiversity loss across the globe, restoration projects need to focus on re‐establishing connectivity in vegetation structure at a landscape scale to facilitate the movement of wildlife. To achieve this requires long‐term commitment, robust partnerships and planning and excellent planting technology underpinned by research. In this Special Issue, consisting of 15 papers, we present a multidisciplinary, multi‐institutional, science‐based approach to environmental restoration, focused on a single geographic region, the Midlands of Tasmania. This introductory paper describes the breadth of the material covered in the series and sets the scene for following papers by describing the Midlands, its geography, climate and history, its extraordinary natural values as a biodiversity hotspot, the degree of degradation that has resulted from 200 years of intensive farming and the objectives of the Midlands restoration project. The Midlands also offers opportunities as a model system for landscape scale restoration given it is a circumscribed region, heterogeneous in land forms and land uses. Furthermore, in land management, there is a high level of cooperation between land owners, government departments, environmental agencies and university researchers. We describe how the contributions from a wide range of disciplines can be focused to meet the challenges of ecological restoration in highly altered agricultural landscapes.

Summary: We overview an array of common garden genetics trials established across multiple sites and embedded in restoration plantings in the harsh, modified Midlands region of the island of Tasmania, Australia. The steps in establishing the common gardens, the diversity of experimental designs employed and their objectives are described. These trials provide a long‐term framework to test species choices and provenancing strategies, as well as enhance our understanding of adaptive genetic variation within key eucalypt species used for ecological restoration. Early results signal genetic‐based differences in early‐age performance, and we showcase the multiple benefits of integrating research infrastructure into restoration plantings.