Successional Categories Research Articles

PHYTOSOCIOLOGICAL CHARACTERIZATION OF AN URBAN FRAGMENT OF INTERIOR ATLANTIC FOREST - PARANÁ, BRAZIL

The Parque Natural Municipal Paulo Gorski, located in western Paraná, comprises an urban remnant of Mixed Ombrophilous Forest. This study aimed to identify tree species and conduct the phytosociological characterization of this fragment of the Atlantic Forest. Monthly visits were made in ten plots (20 x 5 m) to collect fertile samples. A rarefaction curve was generated, and phytosociological parameters, diversity, and the distribution of individuals in diameter classes were calculated. A total of 158 tree individuals were sampled, distributed across 23 families and 47 species (including six exotic ones). Among the species found, 74.4% exhibited zoochoric dispersion syndrome, 19.1% anemochoric, and 6.5% autocoric. Concerning successional category, 63.8% were early successional species. Alchornea triplinervia (Spreng.) Müll.Arg. and Prunus myrtifolia (L.) Urb. had the highest importance values due to their high number of individuals, greater frequency, and basal area. Araucaria angustifolia (Bertol.) Kuntz, an endangered species, also had a high importance value. The Shannon diversity index was 3.43, and evenness was 0.89. Approximately 70% of the individuals were distributed in smaller diameter classes (< 15 cm), forming an inverted J-shape, an expected pattern indicating a regenerative capacity and structure of preserved forest remnants, despite being in an urban area and facing significant human pressures. This urban forest fragment should be preserved, as it contains native and endangered tree species from the region, serving as an ecological corridor, and maintains important ecological and social functions for the region.

The plant community of a stretch of riparian vegetation in the upper Paraná River after 20 years of secondary succession (Batayporã, Mato Grosso do Sul, Brazil)

The study of temporal changes in riparian vegetation is essential for understanding the paths taken by the ecosystem during ecological succession. In order to evaluate the changes in floristic composition, structure, and dynamics of the arboreal vegetation in an area of Semideciduous Seasonal Alluvial Forest, we aim to understand the secondary succession that occurs in the Paraná River floodplain. Based on a study conducted 20 years ago, in the municipality of Batayporã, Mato Grosso do Sul, a re-sampling was carried out in the same area, using the same methodology. Phytosociological and ecological parameters between the two temporal samplings were collected and compared using Student's ‘t’ test, where it was possible to find statistically significant variations (p<0.05) in the vegetation structure. A total of 603 individuals were sampled, distributed among 51 species and grouped in 46 genera and 31 families. The analysis of the distribution of abundance and importance values (IV) of species visualized in the histogram indicated an expected pattern in forest communities, which is the substitution of early successional species for late successional species. For the successional categories, the comparison of IVs revealed higher values for secondary species in both surveys and changes in the positions of climax and pioneer species, directly influencing the IVs values of these categories for the zones. When compared to the result obtained in the previous study, a replacement of the IV values of pioneer species with climax and dead species is noted. The comparisons showed that this phytocoenosis is evolving to a mature successional stage, a result of the decrease in the main anthropic impacts in the area. The results obtained highlight the importance of temporal monitoring of forest areas to expand the understanding of the pathways of ecological succession in this type of environment and provide information to assist in biodiversity conservation.

Spatio-temporal variation of seed rain between urban and rural fragments of humid tropical forests

Introduction: The type of land use surrounding the remnants of tropical forest may generate changes in the characteristics of plant populations and communities. Consequently, there may be a significant reduction in processes of pollination and diasporas dispersion. Therefore, causing changes in some parameters of seed rain. Objective: To characterize and compare seed density, species richness, floristic composition, habit, dispersal syndrome, and successional category of seed rain between urban and rural fragments of Atlantic Forest, in the 2015 and 2016 weather seasons. Methods: The study areas were defined after mapping and quantification of urban and rural occupations around the remnants, based on satellite images. In each fragment, were installed 36 collectors of 0.25 m2. The material was collected monthly during two consecutive years. Results: Seed rain richness was higher in the urban fragment during the rainy season in the two years, whereas it was similar between the fragments in the dry season. The seed density in the rural fragment was higher than in the urban during the rainy season; did not vary in urban between years or between seasons; and it was higher in the rural fragment in the rainy season of one year. There was a difference in the floristic composition of the seed rain between the fragments along time. The variations in the functional attributes of habit, dispersal syndrome, and successional category, were explained by the variables fragment, season, and year. Conclusions: Differences in the characteristics of the seed rain between the fragments might reflect the spatial and temporal heterogeneity, due to the diverse uses of the soil and external pressures (anthropogenic actions) present in the surroundings of the forest fragments and temporal variation in precipitation.

Arboreal community of an Atlantic Forest hillside fragment in São Sebastião/SP

The urban expansion and the growth of economic activities related to tourism added to the port and maritime ones, resulted in the occupation of the Serra do Mar, in the municipality of São Sebastião/SP, increasing environmental degradation. The objective of the study was to evaluate the arboreal patterns in a 0.111 ha fragment around a 4.8 ha clearing in an area of Atlantic Forest in the city of São Sebastião (SP), allowing the revegetation plan to include native species observed in the region. The phytosociological analyses used the Point-Centered Quarter Method (PCQM), using 50 sampling points (30 in close areas, 10 in the forest edge, and 10 near one of the areas drains), with a minimum distance of 20 meters between them. The main variables analyzed were commercial height, diameter to chest height, successional category, and dispersion syndrome. Also, the number of individuals of each species was observed, as well as their basal area (G), absolute and relative density (DA and DR) and dominance (DoA and DoR), relative frequency (FR), and importance value (VI). The results indicate a higher proportion of non-pioneer species, with Guapira oppositte (Vell.) presenting the highest value of importance and density, and the Schizolobium parahyba (Vell.) Blake with the highest basal area. The survey data indicate the richness of species in the study area, serving as a basis for strategies for management and conservation of the environment. Phytosociological studies, although scarce, are important to support the analysis of preservation and the use of nature.

Differential ecological filtering across life cycle stages drive old-field succession in a neotropical dry forest

Abiotic and biotic filters may play differential roles in the plant community organization along forest succession in abandoned fields. However, little is known about how life stage-specific filters influence species replacement during succession. We approach this issue by analyzing changes in community attributes (abundance, species density, species diversity, species composition) and the phylogenetic structure of shrubs and trees at different life stages during the old-field succession of a seasonally tropical dry forest (TDF) in Western Mexico. We raised two main questions: (1) How different are the trajectories of change in community attributes and phylogenetic structure along succession for shrub and tree species at different life-stages? (2) Do different stage-specific trajectories result from differential filtering mechanisms? We used a chronosequence of abandoned pastures and forest sites, classified in five successional categories (with three sites each): Pasture (< 1.5 years fallow age), Early (3.5–5.5 y), Mid (6–8 y), Advanced (13–15 y), and Old-Growth Forest. Identity and abundance of species were recorded at five life stages: seeds in the top soil layer, seedlings (plants emerged from seeds, 10–100 cm height), resprouts (plants emerging from buds in roots or stumps, 10–100 cm height), juvenile [shrubs and trees > 100 cm height and < 2.5 cm diameter at breast height (DBH)], adults (shrubs and trees with DBH ≥ 2.5 cm). Additionally, we quantified the phylogenetic mean parwise distance (MPD) among species, and analyzed the phylogenetic community structure, for each successional category and life stage. We found that early in succession the resprout stage was more abundant and diverse than the seedling stage, while the inverse occurred late in succession. Along the first 15 years of succession, the seedling stage showed a clumped phylogenetic structure (with a strong dominance of legume species), while the resprout stage tended to have an overdispersed one (with species from a wide range of clades). Also, community attributes of the juvenile and adult stages approached those of the old-growth forest, and in both stages the phylogenetic structure changed from clustered to random. Overall, our results suggest that the assembly of shrub and trees communities along succession resulted from a combination of abiotic filtering processes, operating mostly on seedlings (selecting primarily legume drought-tolerant species), and biotic filtering processes, operating mostly in resprouts (generating a taxonomic and phylogenetically diverse regenerative pool). The implications of these results for the management of secondary TDF in human modified landscapes are discussed.

Evaluation of conservation status of plants in Brazil's Atlantic forest: An ethnoecological approach with Quilombola communities in Serra do Mar State Park.

The Atlantic Forest is considered the fourth most important biodiversity hotspot. Although almost 96% of its original area has been devastated, a large part of its remaining conserved area is inhabited by traditional communities. This research focused on two Quilombola communities who reside within the Núcleo Picinguaba of the Serra do Mar State Park, State of São Paulo, Brazil. The objective was to use a combination of ethnoecological and ecological approaches to select priority species for which to develop participatory conservation and sustainable management plans in protected areas in Brazil. We collaborated with community members to collect ethnobotanical and ethnoecological data and then measured the abundance of native species in local forests through phytosociological sampling. We used this information to assess the degree of threat to useful species using the Conservation Priority Index, adding an additional layer of analysis based on habitat successional categories. We then overlayed those useful species identified as highest risk locally with those federally listed as threatened or endangered. Based on this, we identified three species as priority for the development of sustainable management plans: Virola bicuhyba, Cedrella fissilis and Plinia edulis.

Microclimate niche requirements of leaf beetles (Chrysomelidae: Coleoptera) in a successional gradient of low thorn forest in northeastern Mexico

Disturbance caused by loss of vegetal cover modifies interactions between abiotic environment and species, including phytophagous insects such as leaf beetles (Chrysomelidae: Coleoptera). Furthermore, secondary succession changes both resource availability and microclimatic conditions after disturbance, thus influencing species niche requirements. However, despite this importance, effects of such modifications on phytophagous insects remain almost unknown. Therefore, in this study we compared microclimatic niche parameters of leaf beetle communities in a successional gradient of low thorn forest in northeastern Mexico. A chronosequence of four categories with different succession time was delimited (conserved areas, 31, 17 and 4 years) through the analysis of Landsat satellite images (1973, 1986, 2000, 2005 and 2015). In each category, we systematically sampled leaf beetles (using sweep nets) and recorded seven microclimatic variables monthly, during the wet season of 2016 (May–October). In total, 66 species of Chrysomelidae were found, distributed in the four successional categories. Association between communities and microclimatic variables, as well as the number of species significantly related with these changes, decreased with successional time. Relative humidity, temperature and heat index were variables mainly related to these changes, and their specific contributions changed with time. Results suggest that microclimate influences the structuration of the phytophagous insect community after disturbance, but only in areas of recent succession; thus, other factors are operating in conserved areas. Therefore, secondary vegetation areas of different recovery time constitute unique microclimate niches for leaf beetle species, and as such, these need to be accounted for when delimiting conservation areas.

Seasonal microclimatic variation in a succession gradient of low thorn forest in Northeastern Mexico

Global increase in land cover change and deforestation bring about fragmentation of a high proportion of native vegetation areas. Microclimate is among the first modified factors after vegetation loss, effects of such disturbances are critical for species performance. However, both secondary succession and seasonality provoke further modifications in abiotic environment after disturbances. Although microclimate patterns during succession are well studied for several ecosystems, they are practically unknown for low thorn forests. In Northern Mexico, this is an endangered ecosystem characterized by harboring a high percentage of endemics. Measurement of microclimatic factors is crucial for understanding possible consequences of post-disturbance time on species inhabiting this ecosystem. This work aimed to assess seasonal variation of microclimatic patterns in a succession gradient of four categories (conserved areas, 31, 17 and four years of succession). The study area was delimited using Landsat satellite images (1973, 1986, 2000, 2005, and 2013) in a fragment of low thorn forest in Northeastern Mexico. For microclimate characterization we studied wind speed, temperature, relative humidity, heat index, dew point, and evapotranspiration. Variables were measured monthly on eight plots, in each of the four successional categories, during two different seasons: wet (May through October 2016) and dry season (November 2016 through April 2017). A multivariate discriminant function analysis showed that microclimate differs among successional stages. In the wet season, early succession areas were characterized by higher values of heat index and wind speed, contrary to conserved areas. In the dry season, successional differences were attributed to wind speed and relative humidity. Moreover, microclimate differences between categories and importance of variables measured were both higher only during the dry season. Our results show that seasonality influences greatly microclimatic patterns during secondary succession. In addition, each one of the successional categories exhibited unique microclimatic conditions. Remarkably, four, 17, and even 31 years succession categories differed from conserved areas. This work provides evidence on the great relevance of seasonality and microclimate for studying secondary succession. It is suggested to take both factors into consideration when implementing conservation programs concerning endangered habitats such as low thorn forests. As an ecosystem poorly studied, microclimate characterization provided herein, shall help to a better understanding and management of these areas.

Functional morphology of subtropical tree seedlings in southern Brazil

Abstract The objective of this study was to analyze the morphofunctional attributes of Mixed Ombrophyllous Forest species of different successional categories. Fruits were collected from forest remnants in Curitiba, Paraná. It was analyzed the biometrics of seeds and seedlings of all species and the following ratios were estimated: shoot/seedling length, shoot/seedling mass, cotyledons/seedling mass, eophyll/seedling mass and seedling/ seed mass. Statistical differences among sucessional groups were observed in many of the evaluated traits. The variability among species is mainly explained by seedling size, tissue investment for light interception and shoot resource allocation. Late secondary species have larger seedlings with characteristics that indicate slower initial development, dependent on seed reserves. The pioneers species have smaller seedlings but faster development and earlier dependence on photosynthesis. These morphological and functional differences can result in different strategies for the establishment of seedlings in the successional process. The cluster analysis results on formation of two major groups. The first group is comprised of the late secondary species. The second group includes two distinct subgroups that separate the pioneers, and most of the early secondary species. These results indicate that the number and quality of available data should be considered in the definition of successional categories adopted in ecological studies.

Soil Seed Banks in a Forest Under Restoration and in a Reference Ecosystem in Southeastern Brazil

ABSTRACT The current study aims to characterize the soil seed banks in a forest under restoration and in a seasonal semideciduous forest remnant, as well as to quantitatively and qualitatively compare them in order to evaluate the seed bank potential to influence the restoration process. In total, 60 samples of soil seed banks were collected in two adjacent forests (30 in a 2.18-ha forest undergoing restoration process based on the planting of seedlings belonging to different tree species, after the forest was subjected to bauxite mining activity; and 30 in a 5.30-ha preserved forest fragment). The soil seed bank of the forest undergoing restoration recorded higher density of emerged seedlings than that of the reference ecosystem. Although the shrub-tree species in the investigated forests lacked floristic similarity, the highly similar dispersal syndrome distribution and the successional category of shrub-tree species in them have indicated that both forests underwent ecological processes. Therefore, the restoration process implemented in the mined area has successfully recovered the soil seed bank after a few years.

Effects of long-term inter-annual rainfall variation on the dynamics of regenerative communities during the old-field succession of a neotropical dry forest

Effects of long-term rainfall inter-annual variation on regeneration dynamics of tropical dry forests (TDF) are still poorly understood. Such understanding is particularly important to assess the regeneration potential of TDF in landscapes subjected to slash-and-burn farming management. Here, we studied from 2004 to 2016 the effects of inter-annual rainfall variation on the dynamics of regenerative communities of woody species during the old-field succession of a TDF in Western Mexico. Over the study period a severe drought, caused by an El Niño Southern Oscillation (ENSO) event in 2005, and two hurricanes (Jova, 2011, magnitude 2; Patricia, 2015, magnitude 4) were experienced. In 2004, we established a chronosequence of abandoned cattle pastures and old-growth forest sites, which were assigned to four successional categories, each one with three sites: Pasture (0–3 years fallow age), Early (3–5 years), Intermediate (8–12 years), and Old-Growth Forest (without any human disturbance). At each site, seedlings, saplings and resprouts 10–100 cm height of shrub and tree species were tagged, taxonomically identified, measured in height and monitored over 12 continuous year intervals. At each year, all new plants reaching 10 cm height were recorded and considered as recruits. Community rates (recruitment, relative growth rate in height, mortality, species gain and species loss) were calculated per year, considering all plants combined and separating shrub from tree species. All community rates varied notoriously in response to temporal rainfall variability, with almost null interaction with successional category. As expected, mortality and species loss rates declined as the amount of rainfall increased, especially when precipitation of the current and the previous year were taken into account; these rates peaked in the ENSO year and were still high in the following year. Unexpectedly, recruitment and species gain rates also declined with the increase in rainfall, especially with the amount of rainfall in the current year. Overall, community rates of tree species were more responsive than those of shrub species to temporal rainfall variation. The ENSO-related drought event produced a short and transient instability in the plant density and species density of regenerative communities. However, ENSO effects were smoothed out by subsequent rainy years, leading to a net increase in plant density and species density in all successional categories, especially in the younger one. Overall, our study shows that global (e.g. ENSO) and regional (e.g. storms, hurricanes) climate factors play a key role on forest succession, modulating the speed of the TDF regeneration dynamics. We conclude that low impact agricultural land use and the presence of good levels of remnant forest cover in the landscape confers a high potential for regeneration in abandoned agricultural fields, even under the impact of severe droughts and severe hurricanes.

Importance of Nesting Resources and Soil Conditions for the Recovery of Ant Diversity During Secondary Succession in a Tropical Rainforest

The secondary succession of tropical rainforest in abandoned agricultural fields modifies components of species diversity and processes of species colonization and replacement. In general, knowledge on invertebrate reassembly is lacking, even though invertebrate assemblages directly influence the maturation of forests. Ants are especially useful for testing hypotheses about the effects of resource diversity and microhabitat conditions. We experimentally assessed the effects of different successional stages on nest colonization. Then, we assessed whether nesting resources and microhabitat conditions (i.e., abiotic conditions) are potential mechanisms that influence the colonization pattern of twig-dwelling ants along a natural chronosequence for 1 year in the Lacandon region, Mexico. We found that ant species richness in twigs is correlated with total species found in leaf litter. The nest occupancy increased as succession progressed, but species richness did not change. Nests occupation increased to greater artificial nesting resource decomposition rates and lower soil pH. Meanwhile, species richness was increased only with lower soil compaction. Species composition changes among successional categories; the changes were greater with greater soil compaction and soil pH. The diversity of nesting resources did not drive twig-dwelling ant assembly. We conclude that the natural maturation of tropical forest enables greater colonization of twig-dwelling ants, but recovery of the species composition of assemblages after 30 years is incomplete, although it shows a recovery trend.

CARACTERIZAÇÃO DA PRODUÇÃO DE SERAPILHEIRA E DA CHUVA DE SEMENTES EM UMA RESERVA DE FLORESTA ESTACIONAL SEMIDECIDUAL, PARANÁ

O objetivo do estudo foi analisar a produção de serapilheira e a chuva de sementes em um fragmento de Floresta Estacional Semidecidual do oeste do Paraná com 242 ha, que é conhecido como Reserva Particular de Patrimônio Natural Fazenda Santa Maria. O material foi coletado mensalmente de junho/2011 a maio/2012, em nove parcelas de 20 x 20 m, com o uso quatro coletores de 0,5 x 0,5 m em cada parcela. A serapilheira foi triada e pesada, e a chuva de sementes foi avaliada quanto à riqueza, forma de vida, categoria sucessional e síndrome de dispersão das espécies encontradas. A produção anual de serapilheira foi de 11.886 kg ha-1, sendo agosto e setembro os meses de maiores produções. A fração foliar foi a mais representativa com 58,52% do total. Na chuva de sementes foram coletadas 18.300 sementes, distribuídas em 79 morfoespécies, das quais 51 foram identificadas em nível de espécie, oito em nível de gênero e seis em nível de família. Mikania sp., Cecropia pachystachya, Pisonia aculeata, Gouania ulmifolia e Dendropanax cuneatus foram as espécies com maiores densidades relativas. Os meses com maior abundância de sementes foram setembro (19%), outubro (20%), novembro (27%) e março (15%). A forma de vida predominante foi arbórea com 76,27% das espécies, seguida de lianas com 20,34% e herbáceas com apenas 3,39%. Entre as espécies arbóreas, 37% foram representadas pela categoria sucessional de pioneiras, enquanto as categorias secundárias iniciais e tardias representaram 22% cada e as climácicas 20%. A zoocoria predominou entre as síndromes de dispersão (52,54%), enquanto a anemocoria e a autocoria ocorreram em 38,98 e 8,47%, respectivamente. Os resultados foram semelhantes aos encontrados em outros trabalhos realizados em Florestas Estacionais Semideciduais tardias. Assim, por meio deste estudo sobre deposição da serapilheira e chuva de sementes, o fragmento florestal pode ser considerado uma área de floresta tardia e com elevado potencial de regeneração.

Pathways affect vegetation structure and composition in the Atlantic Forest in southeastern Brazil

Although impacts generated by gaps can affect vegetation, few studies have addressed these impacts in the Atlantic Forest. Our aim was to investigate the effects of pathways of varying widths on vegetation structure and composition, considering dispersal syndromes, diversity, life forms, successional categories and threatened and exotic species occurrence in the Atlantic Forest. We studied three pathways with widths of 2, 10 and 20 m, intersecting a protected area in southeastern Brazil. To assess edge effects, plots were established adjacent to paths (edge) and 35 m from the edge (neighborhood), and in a control area without pathways. Wider pathways (10 and 20 m) exhibited reduced tree height and diameter, high liana density, exotic species, and a high proportion of pioneer and anemochorous species. In conclusion, our results indicate that the vegetation structure of narrow pathways (2 m) is similar to the control area, and that wide linear gaps cause negative effects on vegetation and extend to a distance of at least 35 m into the forest interior. Considering that linear gaps generate permanent effects to vegetation and may affect other organisms, we suggest that these effects must be considered for successful management of protected areas, including planning and impact mitigation.

COMPOSIÇÃO E ESTRUTURA DO COMPONENTE ARBÓREO DE MATA COM ACURI NO PANTANAL MATOGROSSENSE, BRASIL

Visando contribuir para o maior conhecimento deste tipo florestal pantaneiro, apresenta-se resultado de levantamento florístico-estrutural realizado em área vulgarmente denominada de “Mata com Acuri”, localizada na RPPN SESC Pantanal (Município de Barão de Melgaço - MT, Brasil - 16º45’ S; 56º15’ W). Os dados florísticos foram obtidos a partir de coletas sistemáticas de material botânico fértil e vegetativo efetuadas na área amostral e entorno desta. Para coleta de dados estruturais, a área foi subdividida em 100 parcelas contíguas de 10 m x 10 m. Dentro de cada uma destas parcelas, todos os indivíduos arbóreos com diâmetro a altura do peito igual ou superior a 5,0 cm e palmeiras foram identificados, mensurados e mapeados, utilizando-se o sistema de coordenadas. Foram amostrados 1224 indivíduos ha-1, representativos de 44 espécies, 43 gêneros e 27 famílias; índice de diversidade H’ = 1,613 (var. 0,003514). Famílias com maior diversidade: Fabaceae (9 spp.), Sapindaceae e Anacardiaceae (3 spp. cada), Bignoniaceae, Malvaceae, Moraceae e Rubiaceae (2 spp. cada). Dentre as espécies amostradas, 39% eram perenifólias; 32% semidecíduas e 29% decíduas. Do total de indivíduos arbóreos amostrados (n=440), 51% eram decíduos; 23% semidecíduos e 26% perenifólios. Attalea phalerata foi a espécie que com maior valor de importância (VI= 121,62), devido à sua alta densidade (64% do total de indivíduos amostrados), frequência (100%) e elevadíssima área basal (74,10 m2.ha-1). Com valores subsequentes registraram-se Anadenanthera colubrina, Triplaris americana e Phyllostylon rhamnoide (VI= 35,41; 28,51; 18,5, respectivamente). A área estudada foi identificada como bastante peculiar em relação a outros locais representativos de Floresta Estacional, especialmente pela presença massiva de Attalea phalerata e ausência de representantes de Myrtaceae. A grande representatividade de espécies pioneiras em associação à elevada densidade de indivíduos dentro desta categoria sucessional reforça o caráter de formação transicional da Mata com Acuri. Em função da alta porcentagem de espécies decíduas e semidecíduas registradas para a área de estudo, classificou-se esta como sendo representativa de Floresta Estacional Decidual.

Partial recovery of a tropical rain forest a half‐century after clear‐cut and selective logging

Summary The extent to which tropical rain forests recover tree species richness, composition and community structure after clear‐cutting or selective harvest is controversial. Thus, the conservation value of forests regenerated after harvest remains unclear, but critically important for biodiversity. We sampled trees from 164 25 × 25 m quadrats across a 160‐km2 tropical rain forest landscape on Hainan Island, China, which had been clear‐cut or selectively harvested and left to recover without management for up to 50 years. Species richness and species abundance distributions were compared among five successional categories to investigate changes in species richness and species abundance over time. Basal areas and three different species similarity indices were compared to reveal temporal changes in species composition and community structure. Species richness recovered faster than species composition and structure in both selectively logged and clear‐cut forests. Both total number of species and number of rare species tended to increase from younger harvested forests through older harvested forests to old‐growth intact forests. Within 20–40 years after harvest species composition of harvested forests tended towards that of old‐growth forests, community similarity between harvested and old‐growth forests decreased subsequently and basal area did not recover, given even a half‐century of succession undisturbed by anthropogenic forces. Shortly after harvest, pioneer species increased rapidly, but shade‐tolerant species required much more time to recover to former abundances. The shift from pioneer species to shade‐tolerant species indicates significant recovery of logged forests. Selectively logged forests recovered more quickly and had higher conservation values than clear‐cut forests. Synthesis and applications. Our findings indicate that logged tropical forests only partially recovered the characteristics of pre‐harvest, primary forest after a half‐century of succession. Recovery of the original tree biodiversity on such post‐harvest landscapes will be slow at best, if measured by species composition or stand structure. Our study amplifies the importance of conserving tropical forest integrity and developing harvest and management approaches that facilitate full recovery of logged tropical forests.

The role of temporal scale in linear edge effects on a submontane Atlantic forest arboreal community

This study aims to detect the composition, abundance patterns, and successional stage distributions exhibited by arboreal species inside and at the linear edge of a submontane seasonal forest in the Chapada Diamantina (12°28'31'S, 41°23'14'W), Bahia, Brazil. The individual plants with breast height diameters ≥5 cm were sampled in 30 quadrats (10 m × 10 m), 15 in the forest edge and 15 inside the forest. Species were classified according to successional category. Phytosociological and diversity indices were calculated. Shannon indices were compared using Hutcheson's t-test, and the remaining parameters were analyzed by ANOVA. Linear edges exerted a high impact on the floristic composition, diversity, and abundance of species, though little interference was observed in the structure of the community, since phytosociological parameters and the proportions of successional categories did not differ between the edge and inner forest fragment. The impact of linear infrastructure was similar to that of other border types. Additionally, even though the distance between forest fragments was very short, an edge effect was observed, which underlines the importance of linear forest edges to biodiversity conservation.

Seed rain analysis of a reforested area in Santa Maria biodiversity corridor, Parana

O corredor de biodiversidade Santa Maria, formado por remanescentes de Floresta Estacional Semidecidual, matas ciliares e uma faixa reflorestada em 2003, visa restaurar a conectividade entre o parque Nacional do Iguaçu e a faixa de proteção do reservatório de Itaipu. Objetivou-se avaliar a dinâmica da chuva de sementes da faixa reflorestada presente no corredor, conhecida como faixa seca, por meio dos parâmetros de diversidade, categoria sucessional, síndrome de dispersão e forma de vida das espécies encontradas. As amostras foram coletadas durante seis meses, ao longo de nove parcelas, utilizando quatro coletores de 0,5 x 0,5 m em cada parcela. Foram registradas 6.423 sementes, distribuídas em 26 morfoespécies, sendo dezenove determinadas ao nível de espécie e três até família. As espécies mais abundantes foram: Cordia trichotoma (Vell.) Arráb. ex Steud., Dalbergia frutescens (Vell.) Britton, Syzygium cumini (L.) Skeels. e Tabernaemontana fuchsiaefolia A. DC. Em relação as mais frequentes, estas foram: sp.1 de Asteraceae, Senegalia polyphylla DC. e Casearia sylvestris Sw. A categoria sucessional pioneira predominou com 59%, seguida de secundárias iniciais com 35% e climácicas com 6%. A forma de vida prevalente foi arbórea e a zoocoria foi à síndrome de dispersão de maior ocorrência. Verificou-se que a chuva de sementes foi composta por espécies de origem autóctones e alóctones, e que os parâmetros avaliados correspondem a fitofisionomia de Floresta Estacional Semidecidual em início de sucessão. Abstract The Santa Maria Biodiversity Corridor which is formed by remnants of seasonal semideciduous Forest, riparian forests and also by reforested zone in 2003, aims at restoring connectivity between the Iguaçu National Park and the Protection Strip of the Itaipu Reservoir. This study intends to evaluate the dynamics of seed rain of reforested zone found in the corridor, known as Dry Strip, through the parameters of diversity, successional category, dispersal syndrome and life form of the species found. The samples were collected during six months, over nine plots, using four collectors of 0,5 x 0,5 min in each plot. We recorded 6423 seeds, distributed in 26 morphospecies, which 19 were identified as the species level and three to the family level. The most abundant species were: Cordiatrichotoma (Vell.) Arráb. exSteud., Dalbergia frutescens (Vell.) Britton, Syzygiumcumini (L.) Skeels and Tabernae Montana fuchsia e foliaA. DC. Regarding the most frequent species, these were: sp1 of Asteraceae, Senegalia polyphylla DC. and Casearia sylvestrisSw. The successional category was predominant with 59%, followed by early secondary with 35% and climax with 6%. The life form predominant was arboreous and the zoochory was the most frequent dispersal syndrome. It was found that the seed rain was composed by autochthonous and allochthonous species, and the evaluated parameters correspond to a semideciduous forest in early succession.

Natural regeneration in a restored bauxite mine in southeast Brazil

Votorantim Metais, Setor de Meio Ambiente, CEP: 36790000, Mirai, MG, Brasil.SUMMARYThe objective of the present study was to verify if, in floristic terms of natural regeneration, a restored bauxite mine in southeast Brazil can be considered successfully restored. Forty plots of 3.0 x 3.0 m were allocated in the area. All shrubs and trees with height ≥ 0.30 m and diameter at 1.30 m height (DBH) ≤ 5.0 cm were identified and classified into successional categories and dispersal syndromes; DSL (diameter at soil level) and height were measured. We use the canonical correspondence analysis (CCA) to verify the correlations between environmental variables (canopy openness, litter decomposition, soil penetration resistance) and vegetation. We found 705 individuals, 80 species and 30 families. The families with the highest species richness were Fabaceae and Melastomataceae. The specie with the highest importance value (IV) was

Effects of ENSO and Temporal Rainfall Variation on the Dynamics of Successional Communities in Old-Field Succession of a Tropical Dry Forest

The effects of temporal variation of rainfall on secondary succession of tropical dry ecosystems are poorly understood. We studied effects of inter-seasonal and inter-year rainfall variation on the dynamics of regenerative successional communities of a tropical dry forest in Mexico. We emphasized the effects caused by the severe El Niño Southern Oscillation (ENSO) occurred in 2005. We established permanent plots in sites representing a chronosequence of Pasture (abandoned pastures, 0–1 years fallow age), Early (3–5), Intermediate (8–12), and Old-Growth Forest categories (n = 3 per category). In total, 8210 shrubs and trees 10 to 100-cm height were identified, measured, and monitored over four years. Rates of plant recruitment, growth and mortality, and gain and loss of species were quantified per season (dry vs. rainy), year, and successional category, considering whole communities and separating seedlings from sprouts and shrubs from trees. Community rates changed with rainfall variation without almost any effect of successional stage. Mortality and species loss rates peaked during the ENSO year and the following year; however, after two rainy years mortality peaked in the rainy season. Such changes could result from the severe drought in the ENSO year, and of the outbreak of biotic agents during the following rainy years. Growth, recruitment and species gain rates were higher in the rainy season but they were significantly reduced after the ENSO year. Seedlings exhibited higher recruitment and mortality rate than sprouts, and shrubs showed higher recruitment than trees. ENSO strongly impacted both the dynamics and trajectory of succession, creating transient fluctuations in the abundance and species richness of the communities. Overall, there was a net decline in plant and species density in most successional stages along the years. Therefore, strong drought events have critical consequences for regeneration dynamics, delaying the successional process and modifying the resilience of these systems.