Restoring native forest understory: The influence of ferns and light in a hawaiian experiment

Ecological restoration is an increasingly important component of sustainable land management. We explore potential facilitative relationships for enhancing the cost-effectiveness of restoring native forest understory, focusing on two factors: (1) overstory shade and (2) possible facilitation by a fern (Dryopteris wallichiana), one of few native colonists of pasture in our montane Hawai\u27i study system. We planted 720 understory tree seedlings and over 4000 seeds of six species under six planting treatments: a full factorial combination of low, medium and high light, situating plantings in either the presence or absence of a mature fern. After three years, 75% of outplanted seedlings survived. Seedling survivorship was significantly higher in the presence of a fern (79% vs. 71% without a fern) and in medium and low light conditions (81% vs. 64% in high light). Relative height was highest at low to medium light levels. After 2.2 years, 2.8% of the planted seeds germinated. We observed no significant differences in seed germination relative to light level or fern presence. Analyzing several approaches, we found nursery germination of seeds followed by outplanting ca. 20% less costly than direct seeding in the field. This study opens new questions about facilitation mechanisms that have the potential to increase the extent and effectiveness of restoration efforts. © 2013 by the authors

Using ecological theory to resolve drivers of variation in restoration outcomes at multiple scales

Restoration ecology is a relatively new subfield of ecology and as a result, there remains a range of knowledge gaps that limit our capacity to meet growing ambitions for global biodiversity restoration. In this thesis, I combine ecological theory with hands-on restoration to investigate variability in ecological restoration outcomes at a range of temporal and spatial scales. One of the major issues facing current restoration activities is the large degree of variation in outcomes. Even at a fine scale such as in a single paddock, stream, or reef, there is significant variation in terms of “success”. Despite recent and repeated discussions in the scientific literature about the issues of variability, there has been no empirical analysis of if variability in restoration outcomes at this scale was significant. I used a meta-analytical approach to assess the effect of restoration on the variability of terrestrial biodiversity at a global scale across a wide range of environments. Next, I focused on a finer scale to assess how restored plant communities develop over time. Using what I believe are the oldest examples of native plant restoration in Australia (using the modern landscape scale method of direct seeding), I asked whether the species and functional diversity of restoration projects continue to decline over a decadal timescale, following earlier studies that find shorter-term declines in species richness in restoration plantings. I also investigated whether including a greater number of species in the seed mix had an effect on the diversity of the restored community after 25–30 years. I zoomed in further still to the individual plant scale possible to ask about drivers of tree mortality and growth in a large restoration planting in southwest Western Australia. I used seven years of monitoring of the same approximately 2000 individual trees and shrubs to understand how growth and survival can be explained by functional traits, neighbourhoods, and individual characteristics. Overall, this thesis brings together a range of relevant ecological theories to better understand variation in restoration at the global, landscape, and individual tree scales. It provides new insights into the significance of variation in restoration outcomes and the factors that contribute to it and will inform the design and management of future restoration projects

To What Extent Are Cattle Ranching Landholders Willing to Restore Ecosystem Services? Constructing a Micro-Scale PES Scheme in Southern Costa Rica

Deforestation and the unsustainable management of agricultural and livestock production systems in tropical mountain areas have caused fragmented and degraded landscapes. Payment for ecosystem services (PES) could be an effective policy instrument with which to reduce deforestation and restore disturbed ecosystems. The national-scale PES program in Costa Rica is recognized as being successful; however, its financial resources have been mostly dedicated to forest protection, and much less to reforestation projects. This paper aims to construct a micro-scale PES scheme by using primary data generated through spatial modeling and socio-economic and stated preference surveys (choice experiment) in southern Costa Rica. The results suggest that, on average, landholders would agree to implement restoration projects on their own private pasturelands if an appropriate holistic place-based approach was applied encompassing biophysical, social, economic, and institutional aspects. Willingness-to-accept values allow payments to be linked to cattle farmers’ estimates of specific ecosystem services (ES) and land opportunity costs. The economic valuation of three ESs (erosion control, water availability, and biodiversity) allows construction of a layered payment scheme, which could encourage the development of a potential partnership between national and local institutions and NGOs as alternative buyers of ESs, reduce transaction costs, and improve household well-being.This research was funded by Fondo de Becas CeNAT-CONARE, Costa Rica, https://cenat.ac.cr/ (accessed on 28 April 2021). The publication process was partly financed by the EKOPOL Research group, recognized by the Basque Government (IT-1365-19)

Above-ground carbon stocks and timber value of old timber plantations, secondary and primary forests in southern Ghana

High deforestation rates, especially in the tropics, currently result in the annual emission of large amounts of carbon, contributing to global climate change. There is therefore an urgent need to take actions to mitigate climate change both by slowing down deforestation and by initiating new sinks. Tropical forest plantations are generally thought to sequester carbon rapidly during the initial years but there is limited knowledge on their long-term potential. In this study, we assessed the carbon sequestration in old (42-47 years) timber plantations of Aucoumea klaineana, Cedrela odorata, Tarrietia utilis, and Terminalia ivorensis, and secondary forests of similar ages, by comparing their basal areas and above-ground carbon stocks (AGC) to that of nearby primary forests. Additionally, we estimated and compared timber volume and stumpage value in the three forest types. Systematic random sampling of ninety-three 20 m x 20 m plots in eleven forest sites (2 secondary forests, 2 primary forests, and 7 timber plantations) was undertaken to determine the effect of forest type on AGC, basal area, timber volume, and stumpage value. After 42 years of growth, mean AGC of the timber plantations (159.7 +/- 14.3 Mg ha(-1)) was similar to that of primary forests (173.0 +/- 25.1 Mg ha(-1)) and both were significantly higher than the mean AGC of the secondary forests (103.6 +/- 12.3 Mg ha(-1)). Mean basal area and timber volume of the timber plantations and secondary forests were similar to that of the primary forests, though in each case the timber plantations had significantly higher values compared to the secondary forests. Mean timber value of the plantations ($8577 ha(-1)) was significantly higher than both secondary ($1870 ha(-1)) and primary forests ($3112 ha(-1)). Contrary to our expectations, naturally regenerated trees (woody recruits) within the timber plantations had similar AGC levels, basal area, timber volume, and value compared to the secondary forests. Long-rotation tropical forest plantations under low-intensity management could achieve higher AGC levels and thus have higher climate change mitigation potential and timber values compared to naturally regenerated secondary forests, and are able to reach values similar to primary forests. Monoculture timber plantations could facilitate the successful colonization of their understoreys by native woody recruits that contribute considerably to stand AGC and timber values. Long-rotation forest plantations in the tropics therefore have a critical role to play in forest rehabilitation and climate change mitigation while having the potential to provide modest financial returns to landowners through selective harvesting of timber and/or payments for carbon sequestration.Peer reviewe

Árvores isoladas promovem a regeneração da restinga em Sergipe: comparação entre espécies.

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Three decades of post-logging tree community recovery in naturally regenerating and actively restored dipterocarp forest in Borneo

Selective logging has affected large areas of tropical forests and there is increasing interest in how to manage selectively logged forests to enhance recovery. However, the impacts of logging and active restoration, by liberation cutting and enrichment planting, on tree community composition are poorly understood compared to trajectories of biomass recovery. Here, we assess the long-term impacts of selective logging and active restoration for biomass recovery on tree species diversity, community composition, and forest structure. We censused all stems ≥2 cm diameter at breast height (DBH) on 46 permanent plots in unlogged, primary forest in the Danum Valley Conservation Area (DVCA; 12 plots, totalling 0.6 ha) and in sites logged 23–35 years prior to the census in the Ulu Segama Forest Reserve adjacent to DVCA (34 plots, totalling 1.7 ha) in Sabah, Malaysian Borneo. Active restoration treatments, including enrichment planting and climber cutting, were implemented on 17 of the logged forest plots 12–24 years prior to the census. Total plot-level basal area and pole (5–10 cm DBH) stem density were lower in logged than unlogged forests, however no difference was found in stem density amongst saplings (2–5 cm DBH) or established trees (≥10 cm DBH). Neither basal area, nor plot-level stem density varied with time since logging at any size class, although sapling and pole stem densities were lower in actively restored than naturally regenerating logged forest. Sapling species diversity was lower in logged than unlogged forest, however there were no other significant effects of logging on tree species richness or diversity indices. Tree species composition, however, differed between logged and unlogged forests across all stem size classes (PERMANOVA), reflected by 23 significant indicator species that were only present in unlogged forest. PERMANOVA tests revealed no evidence that overall species composition changed with time since logging or with active restoration treatments at any size class. However, when naturally regenerating and actively restored communities were compared, two indicator species were identified in naturally regenerating forest and three in actively restored forests. Together our results suggest that selective logging has a lasting effect on tree community composition regardless of active restoration treatments and, even when species richness and diversity are stable, species composition remains distinct from unlogged forest for more than two decades post-harvest. Active restoration efforts should be targeted, monitored, and refined to try to ensure positive outcomes for multiple metrics of forest recovery

The use of nucleation techniques to restore the environment: a bibliometric analysis

AbstractThe population awareness about environmental conservation is raising and this brought about an increase in the number of environmental restoration studies. Nucleation is a technique used for environmental restoration, where small nuclei of vegetation are established within degraded land. The aim of this paper was to evaluate, by doing a bibliometric analysis, the tendencies and gaps in the study of environmental restoration using the nucleation technique. Data were collected using The Web of Science© and Google Scholar© databases, from 1996 to 2012. Keywords used in the search of papers were nucleation, soil recovery, transposition of soil, bird perches, ecological succession, seed rain, restoration ecology, forest regeneration, degraded area and natural regeneration. Results showed that the number of published studies was low, although increasing in the last decade. The majority of the studies used more than one restoration technique or used natural perches as nuclei. Most of the studies were conducted in the Americas and by Brazilian researches. Many studies were not published as papers in scientific journals, but were available as master thesis or monographs. Natural and artificial perches, soil transposition and natural regeneration were the most successful techniques. The number of nucleation studies must increase and spread through the world, and their results need to be published to help other researches in the environmental restoration

Annual Changes In A Bird Assembly On Artificial Perches: Implications For Ecological Restoration In A Subtropical Agroecosystem

Artificial perches are used in tropical forest restoration projects to increase the dispersal of seeds into restored areas. The ability of perches to enhance seed deposition depends on their ability to attract seed dispersing birds, as well as the correlation between the season of bird visits to perches and the phenology of fruit production in adjacent forests. Using data collected from a large-scale restoration project, we characterized the community of birds that utilize artificial perches over the course of one year. We hypothesized that the structure of a bird assemblage that uses artificial perches is affected by seasonal variation. We aimed to describe the richness, abundance and diversity of a bird assemblage on artificial perches in a subtropical Atlantic forest restoration experiment in Southern Brazil. Richness and abundance estimates of the avian fauna were obtained from eight artificial perches placed in four experimental plots (B2 y-old). Parameters of richness and abundance were compared using ANOVA. The bird assemblage was described using SHE analysis [richness (S), diversity (H’) and evenness (E)], with additional estimates of occurrence and dominance. In total, 451 records of 32 ± 3.16 SD species were obtained. Thraupidae was the most numerous family (nine species, 28.12% of the total). Richness and abundance varied seasonally and were highest during spring and summer. Five migratory species of flycatchers were recorded between spring and early autumn. Perches were ineffective in attracting specialized frugivorous birds, emphasizing that seed dispersal tends to be carried out primarily by generalist omnivores in the initial phase of forest regeneration. © 2016, Universidade Estadual de Campinas UNICAMP. All rights reserved.16