Showing papers by "Giselda Durigan published in 2015"

An estimate of the number of tropical tree species

Abstract: The high species richness of tropical forests has long been recognized, yet there remains substantial uncertainty regarding the actual number of tropical tree species. Using a pantropical tree inventory database from closed canopy forests, consisting of 657,630 trees belonging to 11,371 species, we use a fitted value of Fisher's alpha and an approximate pantropical stem total to estimate the minimum number of tropical forest tree species to fall between similar to 40,000 and similar to 53,000, i.e., at the high end of previous estimates. Contrary to common assumption, the Indo-Pacific region was found to be as species-rich as the Neotropics, with both regions having a minimum of similar to 19,000-25,000 tree species. Continental Africa is relatively depauperate with a minimum of similar to 4,500-6,000 tree species. Very few species are shared among the African, American, and the Indo-Pacific regions. We provide a methodological framework for estimating species richness in trees that may help refine species richness estimates of tree-dependent taxa.

Toward an old-growth concept for grasslands, savannas, and woodlands

Abstract: We expand the concept of “old growth” to encompass the distinct ecologies and conservation values of the world's ancient grass-dominated biomes. Biologically rich grasslands, savannas, and open-canopy woodlands suffer from an image problem among scientists, policy makers, land managers, and the general public, that fosters alarming rates of ecosystem destruction and degradation. These biomes have for too long been misrepresented as the result of deforestation followed by arrested succession. We now know that grassy biomes originated millions of years ago, long before humans began deforesting. We present a consensus view from diverse geographic regions on the ecological characteristics needed to identify old-growth grasslands and to distinguish them from recently formed anthropogenic vegetation. If widely adopted, the old-growth grassland concept has the potential to improve scientific understanding, conservation policies, and ecosystem management.

Where Tree Planting and Forest Expansion are Bad for Biodiversity and Ecosystem Services

Abstract: Misperceptions about the world's grassy biomes contribute to their alarming rates of loss due to conversion for agriculture and tree plantations, as well as to forest encroachment. To illustrate the causes and consequences of these misperceptions, we show that the World Resources Institute and the International Union for Conservation of Nature misidentified 9 million square kilometers of ancient grassy biomes as providing “Opportunities” for forest restoration. Establishment of forests in these grasslands, savannas, and open-canopy woodlands would devastate biodiversity and ecosystem services. Such undesired outcomes are avoidable if the distinct ecologies and conservation needs of forest and grassy biomes become better integrated into science and policy. To start with, scientists should create maps that accurately depict grassy biomes at global and landscape scales. It is also crucial that international environmental agreements (e.g., the United Nations Framework Convention on Climate Change) formally recognize grassy biomes and their environmental values.

Conservation in Brazil needs to include non‐forest ecosystems

Abstract: In the past decades, Brazil made important progress in the conservation of forest ecosystems. Non-forest ecosystems (NFE), in contrast, have been neglected, even though they cover large parts of the country and have biodiversity levels comparable to forests. To avoid losing much of its biodiversity and ecosystem services, conservation and sustainable land use policies in Brazil need to be extended to NFE. A strategy for conservation of Brazil's NFE should encompass the following elements: (1) creation of new large protected areas in NFE; (2) enforcement of legal restrictions of land use; (3) extension of subsidy programs and governance commitments to NFE; (4) improvement of ecosystem management and sustainable use in NFE; and (5) improvement of monitoring of land use change in NFE. If Brazil managed to extend its conservation successes to NFE, it not only would contribute significantly to conservation of its biodiversity, but also could take the lead in conservation of NFE world-wide.

Tyranny of trees in grassy biomes

Abstract: ![Figure][1] Highland grassland in Brazil is considered a forest landscape restoration opportunity PHOTO: G. W. FERNANDES Tree planting, fire suppression, and exclusion of megafaunal herbivores (native or domestic) are ecologically reasonable restoration strategies in deforested landscapes

Indicators of restoration success in riparian tropical forests using multiple reference ecosystems

Abstract: Forest restoration by planting trees often accelerates succession, but the trajectories toward reference ecosystems have rarely been evaluated. Using a chronosequence (4–53 years) of 26 riparian forest undergoing restoration in the Brazilian Atlantic Forest, we modeled how the variables representing forest structure, tree species richness and composition, and the proportion of plant functional guilds change through time. We also estimated the time required for these variables to reach different types of reference ecosystems: old-growth forest (OGF), degraded forest, and secondary forest. Among the attributes which follow a predictable trajectory over time are: the basal area, canopy cover, density and tree species richness, as well as proportions of shade tolerant and slow growing species or individuals. Most of the variation in density of pteridophythes, lianas, shrubs and phorophythes, proportion of animal-dispersed individuals, rarefied richness and floristic similarity with reference ecosystems remain unexplained. Estimated time to reach the reference ecosystems is, in general, shorter for structural attributes than for species composition or proportion of functional guilds. The length of this time varies among the three types of reference ecosystems for most attributes. For instance, tree species richness and proportion of shade tolerant or slow growing individuals become similar to secondary forests in about 40 years, but is estimated to take 70 years or more to reach the OGF. Of all the variables considered, canopy cover, basal area, density, and richness of the understory—by their ecological relevance and predictability—are recommended as ecological indicators for monitoring tropical forest restoration success.

On the need of legal frameworks for assessing restoration projects success: new perspectives from São Paulo state (Brazil)

Abstract: Despite growing worldwide commitment to large-scale ecosystem restoration, national public policies on restoration are few, and those that exist tend to be vague. Brazil and especially Sao Paulo state stand out. In a pioneering attempt to improve restoration projects and their outcomes, the Secretariat for the Environment of the State of Sao Paulo has enacted a legal instrument to drive planning and to assess whether the goals and targets of mandatory ecological restoration are being achieved. Regardless of the restoration techniques applied, the effectiveness of mandatory or public-funded projects will henceforth be assessed by using three ecological indicators: (1) ground coverage with native vegetation; (2) density of native plants spontaneously regenerating; and (3) number of spontaneously regenerating native plant species. We analyze how this science-based legal framework is expected to promote greater restoration success, improve cost-effectiveness, and help bridge the all-too-familiar knowledge-action gap in environmental policies. Notably, scientists, professionals, public agents, and stakeholders from different institutions have collaborated to advance the refinement and rolling out of this legal instrument. By 2037, it is expected that more than 300,000 restoration projects will be carried out in Sao Paulo state and monitored using this set of indicators. We also suggest that this approach could be usefully applied to the growing number of ecological restoration programs being carried out worldwide, especially in the context of offset policies intended to achieve serious compensation for environmental degradation or loss of biodiversity.

Padrões fenológicos de 111 espécies de Cerrado em condições de cultivo

Abstract: The knowledge on the phenological patterns for a broad group of species is an important tool to elucidate the function and structure of plant communities. Aiming to describe the phenological rhythms of Cerrado species being cultivated and to verify if they follow the patterns observed in the native communities, we recorded, every two weeks along four years, the phenology of reproductive (flowering, and fruiting) and vegetative (leaf shedding and sprouting) processes of 111 species of Cerrado in the Arboretum of Floresta Estadual de Assis, Sao Paulo State, Brazil. We elaborated a phenogram containing the occurrence of each phenophase in each month, for each species, as well as the frequency of these phenophases during the years of observations. We identified general patterns of fruiting, flowering and leaf dynamics for the whole set of species planted, which correspond to those found in the literature for the phenology of natural communities of Cerrado.

Edge effects in savanna fragments: a case study in the cerrado

Abstract: Background: Although impacts of edge effects on forest ecosystems are well known, their consequences on savannas have rarely been explored.Aims: To investigate the influence of edge effects on the plant community and microclimate of a cerrado fragment in south-eastern Brazil.Methods: Several plant community variables (density, basal area, richness and cover by each vegetation layer) and microclimatic variables (light, air temperature and humidity), were measured in 10 transects across a savanna fragment surrounded by exotic grasses, and were used to fit semi-parametric models relating these variables with the distance from the habitat edge.Results: Differences in microclimate and tree communities were poorly related to distance from the edge. On the other hand, there were detectable edge effects on the ground layer community (i.e. plants less than 50 cm in height). Edges had a negative effect on native plants of this layer (density and richness of all species and cover of native grasses), while favouring ...

Influence of Removal of a Non-native Tree Species Mimosa caesalpiniifolia Benth. on the Regenerating Plant Communities in a Tropical Semideciduous Forest Under Restoration in Brazil

Abstract: Exotic species are used to trigger facilitation in restoration plantings, but this positive effect may not be permanent and these species may have negative effects later on. Since such species can provide a marketable product (firewood), their harvest may represent an advantageous strategy to achieve both ecological and economic benefits. In this study, we looked at the effect of removal of a non-native tree species (Mimosa caesalpiniifolia) on the understory of a semideciduous forest undergoing restoration. We assessed two 14-year-old plantation systems (modified “taungya” agroforestry system; and mixed plantation using commercial timber and firewood tree species) established at two sites with contrasting soil properties in Sao Paulo state, Brazil. The experimental design included randomized blocks with split plots. The natural regeneration of woody species (height ≥0.2 m) was compared between managed (all M. caesalpiniifolia trees removed) and unmanaged plots during the first year after the intervention. The removal of M. caesalpiniifolia increased species diversity but decreased stand basal area. Nevertheless, the basal area loss was recovered after 1 year. The management treatment affected tree species regeneration differently between species groups. The results of this study suggest that removal of M. caesalpiniifolia benefited the understory and possibly accelerated the succession process. Further monitoring studies are needed to evaluate the longer term effects on stand structure and composition. The lack of negative effects of tree removal on the natural regeneration indicates that such interventions can be recommended, especially considering the expectations of economic revenues from tree harvesting in restoration plantings.

Why species composition is not a good indicator to assess restoration success? Counter-response to Reid (2015)

Abstract: The absence of species composition among the indicators of restoration success, recommended for the Brazilian Atlantic Forest by Suganuma and Durigan, was criticized by Reid. In his critic, Reid argues that species composition can be (1) predictable from site history and restoration technique and (2) a surrogate for poor ecosystem functioning and lack of resilience. We disagree on the deterministic view behind the first argument, and the latter is still controversial. Even though, we recommended richness as a good indicator of ecosystem functioning instead of composition—which depends on the exhaustive labor of botanical identification.

Monitoreo a procesos de restauración ecológica aplicado a ecosistemas terrestres

Abstract: Esta guia materializa mas de dos anos de trabajo, pretende ser una herramienta sencilla y muy grafica a aquellos que estan implementando, redactando y evaluando proyectos de restauracion ecologica y que quieran estructurar un buen plan de monitoreo a diversos componentes del ecosistema a intervenir (e.g. flora, fauna, suelos). Por esto, en sus dos capitulos y trece secciones, el libro ha querido abarcar desde los aspectos conceptuales del monitoreo hasta las tecnicas para diversos grupos, seleccionando indicadores simples pero a la vez robustos. Esperamos que esta guia se convierta en una herramienta de referencia para la comunidad cientifica y sobre todo para los practicantes de la restauracion ecologica.

Invasion impact by Pteridium arachnoideum (Kaulf.) Maxon (Dennstaedtiaceae) on a neotropical savanna

Abstract: Whether management intervention is required to control biological invasions depends primarily on demonstrating species losses resulting from such invasions. Brackens of the Pteridium genus are currently regarded as a problem species that act as important ecological filters in the assembly of invaded communities. We investigated the effects of Pteridium arachnoideum invasion on the diversity, structure, floristic composition, and functional traits of cerradao in Assis, Sao Paulo, Brazil. We compared an invaded site with an adjacent non-invaded site. Bracken constrained the establishment of tree species, resulting in a community structure remarkably distinct from the non-invaded area. The density and basal area of the arboreal community were higher in non-invaded areas, but large trees were more frequent in the invaded areas. However, bracken did not reduce tree species diversity. Both richness and diversity were higher in the invaded area, indicating that over time, tree species richness and diversity naturally recovered, albeit slowly, in the invaded area. Therefore, one cannot attribute the loss of richness in the Cerrado vegetation to bracken invasion. Hence, we argue that, in this system, eradication of this invasive species is not likely to be cost effective, and thus, it should be a low management priority.

Tree species attributes and facilitation of natural regeneration in heterogeneous planting of riparian vegetation.

Abstract: Ecological interactions among species, both positive and negative, have a strong influence on the structure of plant communities and their comprehension can contribute to the improvement of techniques for ecological restoration. Facilitation of natural regeneration by trees planted in riparian forest restoration in the Cerrado region was the subject of this study. We sampled 91 trees ten years old, belonging to six species representing different functional groups by seed dispersal syndrome, deciduousness, and Nitrogen-fixing ability. Gaps created by failures in the initial planting were sampled as controls. Density and richness of regenerating plants were use as response variables. The species, their functional attributes, tree size and the environment under the canopy (grass biomass, light flux and soil moisture) were used as explanatory variables. Density and richness of woody plants under the different species varied greatly among species. Variation was partially explained by deciduousness, but mostly by canopy size and shape, which modify the availability of light to plants in the understory. Restoration of riparian forests in the cerrado region by planting trees should prioritize species with the following attributes: large canopy, fast growing, and a certain level of deciduousness. Such species can trigger natural regeneration processes under their canopies and therefore should accelerate restoration.

Atributos de espécies arbóreas e a facilitação da regeneração natural em plantio heterogêneo de mata ciliar

Abstract: IF ' Instituto Floresta Do Estado de Sao Paulo, Floresta Estadual de Assis, Caixa Postal 104