Fauna community trends during early restoration of alluvial open forest/woodland ecosystems on former agricultural land

Vertebrate fauna was studied over 10 years following revegetation of a Eucalyptus tereticornis ecosystem on former agricultural land. We compared four vegetation types: remnant forest, plantings of a mix of native tree species on cleared land, natural regeneration of partially cleared land after livestock removal, and cleared pasture land with scattered paddock trees managed for livestock production. Pasture differed significantly from remnant in both bird and nonbird fauna. Although 10 years of ecosystem restoration is relatively short term in the restoration process, in this time bird assemblages in plantings and natural regeneration had diverged significantly from pasture, but still differed significantly from remnant. After 10 years, 70 and 66% of the total vertebrate species found in remnant had been recorded in plantings and natural regeneration, respectively. Although the fauna assemblages within plantings and natural regeneration were tracking toward those of remnant, significant differences in fauna between plantings and natural regeneration indicated community development along different restoration pathways. Because natural regeneration contained more mature trees (dbh > 30 cm), native shrub species, and coarse woody debris than plantings from the beginning of the study, these features possibly encouraged different fauna to the revegetation areas from the outset. The ability of plantings and natural regeneration to transition to the remnant state will be governed by a number of factors that were significant in the analyses, including shrub cover, herbaceous biomass, tree hollows, time since fire, and landscape condition. Both active and passive restoration produced significant change from the cleared state in the short term.     

Differences in mammal communities between forest fragments and restoration areas in the Atlantic Forest

The persistence of larger mammals in fragmented forest landscapes depends not only on the protection of remaining habitats but also on ecological restoration sites. It is known that the landscape context is an important predictor of species persistence, abundance and distribution. Here we evaluate how landscape characteristics influence the recovery of larger mammals in ecological restoration sites. We assess the richness and composition of mammals in forest fragments and restoration sites using landscape metrics such as forest cover and connectivity. Forest fragments and restoration sites present the same richness (n = 26), but differ in species composition. Some seed-dispersing mammals were absent in restoration areas, such as Alouatta guariba (brown howler monkey) and Coendou spinosus (paraguayan hairy dwarf porcupine). The percentage of forest cover in the landscape was responsible for 29.09% of the variation in species composition between the evaluated forest formations, exerting a positive or negative influence depending on the species requirements. The results demonstrate the importance of considering not only landscape metrics in an ecological restoration plan, but also the historical landscape context, such as the fauna composition before the disturbance and how these species respond to environmental changes, thus improving the success of future ecological restoration measurements and policies.     

Landscape Pattern Dynamics and Mechanisms during Vegetation Restoration: A Multiscale,Hierarchical Patch Dynamics Approach

The spatial pattern of vegetation changes during ecological restoration, and these changes are affected by the process of restoration. The objective of this study was to integrate the pattern and mechanism of forest restoration in the Dinghushan Nature Reserve (DNR), Guangdong, China, based on data from remote sensing and long‐term field observations. We studied the pattern dynamics of three main forest types and their underlying mechanisms during restoration following a multiscale, hierarchical patch dynamics framework that integrates population, community, and landscape processes. Remote sensing data were used to determine the changes in landscape pattern during different periods of forest restoration from 1978 to 2006. At the landscape scale, the number, area, and perimeter of the needle/broad‐leaved mixed forest (MF) and the evergreen broad‐leaved forest (BF) increased, whereas those of the tropical needle‐leaved forest (NF) decreased during succession. Our analysis based on long‐term field observations indicated that the change rate of NF was lower than that of MF during 1981–1996, but became much higher during 1996–2007. The rate of change in landscape pattern and the progression of succession stages were consistent with each other. Our results also showed that species regeneration and community succession are the biological basis of forest landscape dynamics during vegetation restoration. Landscape pattern analysis allowed us to show “what” happened during vegetation restoration and “where,” and population and community analysis indicated “why” and “how” it happened.     

Recovery of amphibian,reptile, bird and mammal diversity during secondary forest succession in the tropics

In tropical regions, many studies have focused on how vegetation and ecosystem processes recover following the abandonment of anthropogenic activities, but less attention has been given to the recovery patterns of vertebrates. Here we conduct a meta‐analysis (n = 147 studies) of amphibian, reptile, bird and mammal recovery during tropical secondary forest succession (i.e. natural regeneration). For each taxonomic group, we compared changes in species richness and compositional similarity during natural secondary succession to reference forests (mature or old growth forest). In addition, we evaluated the response of forest specialists and the change in bird and mammal functional groups during natural secondary succession in the tropical moist forest biome. Overall, species richness of all groups reached levels of the reference forests during natural secondary succession, but this was not the case for species compositional similarity. The delay in recovery of forest specialists may be the reason for the delay in recovery of species compositional similarity. Overall, vertebrate recovery increased with successional stage, but other potential predictors of diversity recovery, such as, the geographical setting (amphibian and reptile species compositional similarity recovered more rapidly on islands), rainfall (mammal species richness and compositional similarity recovered faster in regions of low rainfall), and the landscape context (amphibian, reptile and mammal species compositional similarity recovered faster in regions with more forest patches) influenced vertebrate recovery. These results demonstrate the important role of secondary forests in providing habitat for many vertebrates, but the slow recovery of species compositional similarity, forest specialists and some functional groups (e.g. insectivorous birds) highlighted the challenge of secondary forest persistence, and strongly argues for the continued protection of old growth/mature forest as habitat for forest specialists and as sources for secondary forest sites.     

Natural regeneration in the context of large‐scale forest and landscape restoration in the tropics

Large‐scale and long‐term restoration efforts are urgently needed to reverse historical global trends of deforestation and forest degradation in the tropics. Restoration of forests within landscapes offers multiple social, economic, and environmental benefits that enhance lives of local people, mitigate effects of climate change, increase food security, and safeguard soil and water resources. Despite rapidly growing knowledge regarding the extent and feasibility of natural regeneration and the environmental and economic benefits of naturally regenerating forests in the tropics, tree planting remains the major focus of restoration programs. Natural regeneration is often ignored as a viable land‐use option. Here, we assemble a set of 16 original papers that provide an overview of the ecological, economic, and social dimensions of forest and landscape restoration (FLR), a relatively new approach to forest restoration that aims to regain ecological integrity and enhance human well‐being in deforested or degraded forest landscapes. The papers describe how spontaneous (passive) and assisted natural regeneration can contribute to achieving multiple social and ecological benefits. Forest and landscape restoration is centered on the people who live and work in the landscape and whose livelihoods will benefit and diversify through restoration activities inside and outside of farms. Given the scale of degraded forestland and the need to mitigate climate change and meet human development needs in the tropics, harnessing the potential of natural regeneration will play an essential role in achieving the ambitious goals that motivate global restoration initiatives.     

Water availability drives aboveground biomass and bird richness in forest restoration plantings to achieve carbon and biodiversity cobenefits

To combat global warming and biodiversity loss, we require effective forest restoration that encourages recovery of species diversity and ecosystem function to deliver essential ecosystem services, such as biomass accumulation. Further, understanding how and where to undertake restoration to achieve carbon sequestration and biodiversity conservation would provide an opportunity to finance ecosystem restoration under carbon markets. We surveyed 30 native mixed‐species plantings in subtropical forests and woodlands in Australia and used structural equation modeling to determine vegetation, soil, and climate variables most likely driving aboveground biomass accrual and bird richness and investigate the relationships between plant diversity, aboveground biomass accrual, and bird diversity. We focussed on woodland and forest‐dependent birds, and functional groups at risk of decline (insectivorous, understorey‐nesting, and small‐bodied birds). We found that mean moisture availability strongly limits aboveground biomass accrual and bird richness in restoration plantings, indicating potential synergies in choosing sites for carbon and biodiversity purposes. Counter to theory, woody plant richness was a poor direct predictor of aboveground biomass accrual, but was indirectly related via significant, positive effects of stand density. We also found no direct relationship between aboveground biomass accrual and bird richness, likely because of the strong effects of moisture availability on both variables. Instead, moisture availability and patch size strongly and positively influenced the richness of woodland and forest‐dependent birds. For understorey‐nesting birds, however, shrub cover and patch size predicted richness. Stand age or area of native vegetation surrounding the patch did not influence bird richness. Our results suggest that in subtropical biomes, planting larger patches to higher densities, ideally using a diversity of trees and shrubs (characteristics of ecological plantings) in more mesic locations will enhance the provision of carbon and biodiversity cobenefits. Further, ecological plantings will aid the rapid recovery of woodland and forest bird richness, with comparable aboveground biomass accrual to less diverse forestry plantations.     

Recovery of rain forest soil seed banks under different reforestation pathways in eastern Australia

Summary Seed availability is a major factor limiting the recruitment of rain forest to cleared land, but little is known about the composition of the soil seed bank under different reforestation pathways. We quantified changes in the viable soil seed bank following rain forest clearing and pasture establishment and subsequent reforestation in subtropical eastern Australia. Major reforestation pathways in the region include planting of a diverse suite of native trees for ecological restoration purposes, autogenic regrowth dominated by the non‐native tree Camphor Laurel (Cinnamomum camphora) and management of this regrowth to accelerate the development of a native tree community. These pathways differ considerably in cost: restoration plantings are expensive, autogenic regrowth is free, whilst managing regrowth generally costs much less than restoration plantings. We surveyed five sites within each of three reforestation pathways as well as reference sites in remnant rain forest and pasture. The composition of the seed bank was determined by germinating plants from soil samples collected from each site. Germinants were classified into several functional groups according to life form, origin, dispersal mode and successional stage. The majority of functional groups varied significantly in abundance or richness between rain forest and pasture sites. Most of the functional groups that varied between rain forest and pasture were restored to values similar to rain forest by at least one of the three reforestation pathways examined. The species richness of native woody plants in the soil seed bank was slightly higher in restoration plantings than in autogenic or managed regrowth; nevertheless, the species richness and abundance of native woody plants and vines were higher in the seed bank of autogenic regrowth than pasture, and both attributes were enhanced by the management of regrowth sites. The results of this study show that autogenic regrowth can make an important contribution to rain forest restoration at a landscape scale. The optimal reforestation approach or mix of approaches will depend on the desired rate of recovery and the resources available for restoration.     

Legacy forest structure increases bird diversity and abundance in aging young forests

Many studies have demonstrated the importance of early‐successional forest habitat for breeding bird abundance, composition, and diversity. However, very few studies directly link measures of bird diversity, composition and abundance to measures of forest composition, and structure and their dynamic change over early succession. This study examines the relationships between breeding bird community composition and forest structure in regenerating broadleaf forests of southern New England, USA, separating the influences of ecological succession from retained stand structure. We conducted bird point counts and vegetation surveys across a chronosequence of forest stands that originated between 2 and 24 years previously in shelterwood timber harvests, a silvicultural method of regenerating oak‐mixed broadleaf forests. We distinguish between vegetation variables that relate to condition of forest regeneration and those that reflect legacy stand structure. Using principal components analyses, we confirmed the distinction between regeneration and legacy vegetation variables. We ran regression analysis to test for relationships between bird community variables, including nesting and foraging functional guild abundances, and vegetation variables. We confirmed these relationships with hierarchical partitioning. Our results demonstrate that regenerating and legacy vegetation correlate with bird community variables across stand phases and that the strength with which they drive bird community composition changes with forest succession. While measures of regeneration condition explain bird abundance and diversity variables during late initiation, legacy stand structure explains them during stem exclusion. Canopy cover, ground‐story diversity, and canopy structure diversity are the most powerful and consistent explanatory variables. Our results suggest that leaving varied legacy stand structure to promote habitat heterogeneity in shelterwood harvests contributes to greater bird community diversity. Interestingly, this is particularly important during the structurally depauperate phase of stem exclusion of young regenerating forests.     

Effect of forest landscapes composition and configuration on bird community and its functional traits in a hotspot of biodiversity of Chile

Understanding the effect of landscape configuration on the bird species richness and their functional traits (dietary preferences) is important to link the conservation and restoration plans to the production of the crops. Our aims were: 1) to study the influence of forest types (native, mixed and plantations) on the bird species richness in two agroforestry landscapes (heterogeneous/homogeneous); 2) to assess the effect of size/density of forest patches in the birds’ functional traits; 3) to evaluate the effect of isolated trees on them, and 4) to discuss conservation and restoration measures for the birds’ functional traits in agroforestry landscapes. We used hierarchical occupancy models to evaluate the effect of different landscape metrics and detectability measures on bird communities. We recorded a total of 64 bird species. The estimated species richness was considerable higher in homogeneous landscape (31.7 ± 2.7) than heterogeneous (27.3 ± 2.5). Our results showed the bird assemblage had a positive trend with native forests, negative with mixed forests and neutral trend for plantations. The granivores and insectivore’s species showed significant preferences for homogeneous landscape, while omnivores had significant preferences for heterogeneous landscape. Carnivores/Piscivores and herbivores/frugivores species did not show preferences by any landscape type. The response of functional traits depended on different forests attributes. The isolated trees had a significant effect on the birds’ functional traits. In conclusion, it is necessary a deep knowledge about the relationship between the landscape configuration and the bird species richness/functional traits. These findings could help in the future with the conservation, restoration, and rewilding policies in this important hotspot of biodiversity, avoiding alterations in the ecosystem services.     

Forest Fragmentation Drives the Loss of Insectivorous Birds and an Associated Increase in Herbivory

Insectivorous birds are known to play a decisive role for the natural control of herbivorous insects. Thus, they enhance the growth, reproduction, and survival of plant individuals and in the long‐term benefit plant regeneration. However, particularly in the tropics, forest fragmentation has been suggested to cause a loss of insectivorous birds. Yet, it is unclear whether this hampers the trophic control of herbivorous insects with potential consequences for plants. Therefore, we investigated the effect of increasing forest fragmentation on tritrophic interactions between insectivorous birds, herbivorous insects, and plants in a subtropical forest landscape, South Africa. We monitored the community composition of birds and estimated insectivorous bird abundances along a gradient of forest fragmentation. In the same sites, we installed bird exclosures on a common plant species (Englerophytum natalense) to assess effects of the trophic control of insectivorous birds on herbivorous insects and leaf area loss (LAL). Forest fragmentation strongly shaped the functional composition of bird communities, particularly through a loss of forest‐dependent insectivorous birds. Moreover, LAL was higher within bird exclosures than on control branches and increased with increasing forest fragmentation on the control branches. Altogether, forest fragmentation seems to hamper the trophic control of herbivorous insects by insectivorous birds through changes in the community composition. This, in turn, may interfere with tritrophic interactions and ecological processes. Thus, conservation efforts aiming at enhancing the natural control of herbivorous insects should focus on the maintenance of continuous indigenous forests that are well‐connected to smaller forest fragments on the landscape scale.     

Effects of forest modification on bird community composition and seed removal in a heterogeneous landscape in South Africa

Human disturbance threatens and modifies forest ecosystems worldwide. Previous studies have investigated the effects of human impact on local bird communities in disturbed forests, but we still lack information on how bird species richness and ecological processes respond to different forest modifications present at a landscape scale. In a heterogeneous South African landscape, we chose six types of indigenous scarp forest, differing in the intensity of human disturbance: continuous natural forests and natural forest fragments in nature reserves, forest fragments in eucalyptus plantations, fragments in the agricultural matrix, forest gardens and secondary forests in game reserves. In 36 study sites, we investigated the bird community using point counts and observed the seed removal of birds at the native tree species Celtis africana. Species richness did not differ among the forest types, but abundance varied significantly with most birds observed in fragments in the agricultural matrix, forest gardens, and secondary forests. The higher bird abundance in these forests was mainly due to forest generalists, shrubland and open country species whereas forest specialists were rarely present. Changes in species composition were also confirmed by multivariate analysis which clearly separated bird communities by forest type. Frugivore abundance in C. africana was highest in natural forest fragments, fragments in the agricultural matrix, forest gardens and secondary forests. The same trend was found for the estimated total number of fruits removed per C. africana tree, though the differences among forest types were not significant. Consequently, modified forests seem to maintain important ecological functions as they provide food sources for generalist species which may, due to their mobility, enhance natural plant regeneration. However, we could show that protected forest habitats are important refugees for specialist species sensitive to human disturbance.     

Avifaunal responses to habitat fragmentation in the threatened littoral forests of south-eastern Madagascar

Aim Madagascar's lowland forests are both rich in endemic taxa and considered to be seriously threatened by deforestation and habitat fragmentation. However, very little is known about how these processes affect biodiversity on the island. Herein, we examine how forest bird communities and functional groups have been affected by fragmentation at both patch and landscape scales, by determining relationships between species richness and individual species abundance and patch and landscape mosaic metrics. Location Littoral forest remnants within south‐eastern Madagascar. Methods We sampled 30 littoral forest remnants in south‐eastern Madagascar, within a landscape mosaic dominated by Erica spp. heathland. We quantified bird community composition within remnants of differing size, shape and isolation, by conducting point counts in November–December in 2001 and October–November 2002. Each remnant was characterized by measures of remnant area, remnant shape, isolation, and surrounding landscape complexity. We used step‐wise regression to test the relationship between bird species richness and landscape structural elements, after correcting for sampling effort. Relationships between bird species abundances and the landscape variables were investigated with Canonical Correspondence Analysis and binomial logistic regression modelling. Results Bird species richness and forest‐dependent bird species richness were significantly (P < 0.01) explained by remnant area but not by any measure of isolation or landscape complexity. The majority of forest‐dependent species had significant relationships with remnant area. Minimum area requirements for area‐sensitive species ranged from 15 to 150 ha, with the majority of species having area requirements > 30 ha. Surprisingly, there was no relationship between bird body size and minimum area requirement. Forest‐dependent canopy insectivorous species and large canopy frugivorous species were the most sensitive functional groups, with > 90% species sensitivity within each group. The distribution of four forest‐dependent species also appeared to be related to remnant shape where remnant area was < 100 ha. Main conclusions The majority of forest‐dependent species, including many that are considered widespread and common, were found to have significant relationships with fragment size, indicating that they are sensitive to processes associated with habitat loss and fragmentation. As deforestation and habitat fragmentation remain serious problems on the island, it follows that many forest‐dependent bird species will decline in abundance and become locally extinct. At the regional scale, we urge that large (> 200 ha) blocks of littoral forest are awarded protected status to preserve their unique bird community.     

Effects of windthrow disturbance on a forest bird community depend on spatial scale

Community structure is expected to be affected by spatial heterogeneity in a landscape. We examined the spatial-scale-dependent effects of windthrow caused by a large typhoon on a forest bird community. Typhoon events of this magnitude are rare in Hokkaido, Japan, occurring only once or twice a century. To assess the “functional spatial scale” at which bird groups (community, species, body-size class, and foraging guild) specifically responded to landscape heterogeneity, the canopy gap rate (CGR, gap percentage) was evaluated at different spatial scales by varying the radius of a circular landscape sector from 100 to 500 m stepwise by 10 m. We then analysed bird community responses, in terms of species richness and abundance, to CGR. Bird species richness did not significantly depend on CGR. In contrast, abundance was significantly dependent on CGR in many groups (species, body-size class, and foraging guild). The guild-level response was clearer than the species-level response, which suggests that the integration and filtration of species traits by guild can reveal a clear response of bird abundance to the extent of canopy gaps. For example, the scale dependence of responses to disturbance clearly varied among body-size classes, where larger birds had larger functional spatial scales. These results reveal that different groups of organisms have different functional spatial scales at which they respond to habitat heterogeneity. Our results also suggest that monitoring only a small number of species could be misleading for conserving biodiversity at the landscape level.     

Natural regeneration as a tool for large‐scale forest restoration in the tropics: prospects and challenges

A major global effort to enable cost‐effective natural regeneration is needed to achieve ambitious forest and landscape restoration goals. Natural forest regeneration can potentially play a major role in large‐scale landscape restoration in tropical regions. Here, we focus on the conditions that favor natural regeneration within tropical forest landscapes. We illustrate cases where large‐scale natural regeneration followed forest clearing and non‐forest land use, and describe the social and ecological factors that drove these local forest transitions. The self‐organizing processes that create naturally regenerating forests and natural regeneration in planted forests promote local genetic adaptation, foster native species with known traditional uses, create spatial and temporal heterogeneity, and sustain local biodiversity and biotic interactions. These features confer greater ecosystem resilience in the face of future shocks and disturbances. We discuss economic, social, and legal issues that challenge natural regeneration in tropical landscapes. We conclude by suggesting ways to enable natural regeneration to become an effective tool for implementing large‐scale forest and landscape restoration. Major research and policy priorities include: identifying and modeling the ecological and economic conditions where natural regeneration is a viable and favorable land‐use option, developing monitoring protocols for natural regeneration that can be carried out by local communities, and developing enabling incentives, governance structures, and regulatory conditions that promote the stewardship of naturally regenerating forests. Aligning restoration goals and practices with natural regeneration can achieve the best possible outcome for achieving multiple social and environmental benefits at minimal cost.     

Incorporating natural regeneration in forest landscape restoration in tropical regions: synthesis and key research gaps

Extensive tropical forest loss and degradation have stimulated increasing awareness at the international policy level of the need to undertake large‐scale forest landscape restoration (FLR). Natural regeneration offers a cost‐effective way to achieve large‐scale FLR, but is often overlooked in favor of tree plantations. The studies presented in this special issue show how natural regeneration can become an important part of FLR and highlight the ecological, environmental, and social factors that must be considered to effectively do so. They also identify major knowledge gaps and outline a research agenda to support the use of natural regeneration in FLR. Six central questions emerge from these studies: (1) What are the ecological, economic, and livelihood outcomes of active and passive restoration interventions?; (2) What are the tradeoffs and synergies among ecological, economic, and livelihood outcomes of natural regeneration, restoration and productive land uses, and how do they evolve in the face of market and climate shocks?; (3) What diagnostic tools are needed to identify and map target areas for natural regeneration?; (4) How should spatial prioritization frameworks incorporate natural regeneration into FLR?; (5) What legal frameworks and governance structures are best suited to encourage natural regeneration and how do they change across regions and landscapes?; (6) What financial mechanisms can foster low‐cost natural regeneration? Natural regeneration is not a panacea to solve tensions and conflicts over land use, but it can be advantageous under some circumstances. Identifying under what conditions this is the case is an important avenue for future research.     

The role of land-use history in driving successional pathways and its implications for the restoration of tropical forests

Secondary forests are increasingly important components of human-modified landscapes in the tropics. Successional pathways, however, can vary enormously across and within landscapes, with divergent regrowth rates, vegetation structure and species composition. While climatic and edaphic conditions drive variations across regions, land-use history plays a central role in driving alternative successional pathways within human-modified landscapes. How land use affects succession depends on its intensity, spatial extent, frequency, duration and management practices, and is mediated by a complex combination of mechanisms acting on different ecosystem components and at different spatial and temporal scales. We review the literature aiming to provide a comprehensive understanding of the mechanisms underlying the long-lasting effects of land use on tropical forest succession and to discuss its implications for forest restoration. We organize it following a framework based on the hierarchical model of succession and ecological filtering theory. This review shows that our knowledge is mostly derived from studies in Neotropical forests regenerating after abandonment of shifting cultivation or pasture systems. Vegetation is the ecological component assessed most often. Little is known regarding how the recovery of belowground processes and microbiota communities is affected by previous land-use history. In published studies, land-use history has been mostly characterized by type, without discrimination of intensity, extent, duration or frequency. We compile and discuss the metrics used to describe land-use history, aiming to facilitate future studies. The literature shows that (i) species availability to succession is affected by transformations in the landscape that affect dispersal, and by management practices and seed predation, which affect the composition and diversity of propagules on site. Once a species successfully reaches an abandoned field, its establishment and performance are dependent on resistance to management practices, tolerance to (modified) soil conditions, herbivory, competition with weeds and invasive species, and facilitation by remnant trees. (ii) Structural and compositional divergences at early stages of succession remain for decades, suggesting that early communities play an important role in governing further ecosystem functioning and processes during succession. Management interventions at early stages could help enhance recovery rates and manipulate successional pathways. (iii) The combination of local and landscape conditions defines the limitations to succession and therefore the potential for natural regeneration to restore ecosystem properties effectively. The knowledge summarized here could enable the identification of conditions in which natural regeneration could efficiently promote forest restoration, and where specific management practices are required to foster succession. Finally, characterization of the landscape context and previous land-use history is essential to understand the limitations to succession and therefore to define cost-effective restoration strategies. Advancing knowledge on these two aspects is key for finding generalizable relations that will increase the predictability of succession and the efficiency of forest restoration under different landscape contexts.     

Ecological outcomes of agroforests and restoration 15 years after planting

Large‐scale forest restoration relies on approaches that are cost‐effective and economically attractive to farmers, and in this context agroforestry systems may be a valuable option. Here, we compared ecological outcomes among (1) 12–15‐year‐old coffee agroforests established with several native shade trees, (2) 12–15‐year‐old high‐diversity restoration plantations, and (3) reference old‐growth forests, within a landscape restoration project in the Pontal do Paranapanema region, in the Atlantic Forest of southeastern Brazil. We compared the aboveground biomass, canopy cover, and abundance, richness, and composition of trees, and the regenerating saplings in the three forest types. In addition, we investigated the landscape drivers of natural regeneration in the restoration plantations and coffee agroforests. Reference forests had a higher abundance of trees and regenerating saplings, but had similar levels of species richness compared to coffee agroforests. High‐diversity agroforests and restoration plantations did not differ in tree abundance. However, compared to restoration plantations, agroforests showed higher abundance and species richness of regenerating saplings, a higher proportion of animal‐dispersed species, and higher canopy cover. The abundance of regenerating saplings declined with increasing density of coffee plants, thus indicating a potential trade‐off between productivity and ecological benefits. High‐diversity coffee agroforests provide a cost‐effective and ecologically viable alternative to high‐diversity native tree plantations for large‐scale forest restoration within agricultural landscapes managed by local communities, and should be included as part of the portfolio of reforestation options used to promote the global agenda on forest and landscape restoration.     

Ants as ecological indicators of rainforest restoration: Community convergence and the development of an Ant Forest Indicator Index in the Australian wet tropics

Ecosystem restoration can help reverse biodiversity loss, but whether faunal communities of forests undergoing restoration converge with those of primary forest over time remains contentious. There is a need to develop faunal indicators of restoration success that more comprehensively reflect changes in biodiversity and ecosystem function. Ants are an ecologically dominant faunal group and are widely advocated as ecological indicators. We examine ant species and functional group responses on a chronosequence of rainforest restoration in northern Australia, and develop a novel method for selecting and using indicator species. Four sampling techniques were used to survey ants at 48 sites, from grassland, through various ages (1–24 years) of restoration plantings, to mature forest. From principal components analysis of seven vegetation metrics, we derived a Forest Development Index (FDI) of vegetation change along the chronosequence. A novel Ant Forest Indicator Index (AFII), based on the occurrences of ten key indicator species associated with either grassland or mature forest, was used to assess ant community change with forest restoration. Grasslands and mature forests supported compositionally distinct ant communities at both species and functional levels. The AFII was strongly correlated with forest development (FDI). At forest restoration sites older than 5–10 years that had a relatively closed canopy, ant communities converged on those of mature rainforest, indicating a promising restoration trajectory for fauna as well as plants. Our findings reinforce the utility of ants as ecological indicators and emphasize the importance of restoration methods that achieve rapid closed‐canopy conditions. The novel AFII assessed restoration status from diverse and patchily distributed species, closely tracking ant community succession using comprehensive species‐level data. It has wide applicability for assessing forest restoration in a way that is relatively independent of sampling methodology and intensity, and without a need for new comparative data from reference sites.     

Restoration goals: Why are fauna still overlooked in the process of recovering functioning ecosystems and what can be done about it?

Despite the evidence that fauna play complex and critical roles in ecosystems (e.g. pollination and nutrient cycling) and the knowledge that they need to be considered in restoration, fauna often remain poorly represented in restoration goal setting, monitoring and assessments of restoration success. Fauna clearly are integral to the aspirations of achieving full ecosystem recovery. However, over‐reaching assumptions about the unassisted return of fauna to restored sites, low investment in fauna monitoring, and minimal consideration of the requirements for fauna monitoring in regulatory guidance and standards appear to have led to the historically vegetation‐centric approaches to rehabilitation and ecological restoration. We argue that ecological complexities render assumptions of unassisted fauna return inappropriate in many situations and may represent a missed opportunity to enhance ecological outcomes and improve restoration trajectories. We advocate for greater consideration of fauna as facilitators of ecological restoration and, particularly for well‐funded projects, for monitoring to place greater emphasis on examining the behaviour and resilience of restored fauna communities. There is a clear need for both industry and regulators to recognise that fauna can be crucial facilitators of restoration and appreciate that the return and monitoring of functional faunal communities can be costly, challenging and may require detailed study across a wide range of taxonomic groups. Failure to advance from business as usual models may risk leaving a legacy of ostensibly functional, but biodiversity‐depauperate, restored ecosystems.     

Tree and bird functional groups as indicators of recovery of regenerating subtropical coastal dune forests

Functional diversity indicators are increasingly used to monitor forest function recovery because they connect biodiversity to ecosystem functions. However, identifying which functions deviate from a reference forest has not received much attention, despite its potential to inform restoration interventions. In this study, we used functional groups to assess the recovery of ecosystem functions in regenerating coastal dune forests. We surveyed birds and trees in forest of different ages and a reference old‐growth forest in KwaZulu‐Natal, South Africa. We classified species into functional groups for each taxa based on functional traits or a priori defined categories (i.e. guilds) and quantified the number of species within functional groups as a proxy of function stability. Bird species density followed an asymptotic trajectory, reaching old‐growth forest values after 25 years. Insectivores and granivores showed saturating trajectories, whereas small frugivores and generalists increased linearly. With the exception of large frugivores, relative abundances of bird functional groups progressed towards old‐growth forest values as the forest aged. Tree species density increased linearly with forest age. In contrast to old‐growth forests, large‐canopy trees and understory shrubs were under‐represented, while mid‐canopy trees dominated regenerating forests. Our result suggests that most bird, but not tree, functions may have been restored. The trend in large frugivore numbers may warrant further investigation, as their low numbers may have hampered the recovery of tree functions. We conclude that functional group trajectories can track functions that deviate from a benchmark, and may therefore direct adaptive actions to recover the stability of regenerating forest.