Gustavo Ribas Curcio

Fitossociologia do sub-bosque de uma Floresta Ombrófila Mista Aluvial,no município de Araucária, PR

This research is part of the work of the Barigui river’s floodplain forest (Barddal, 2002) and analyse the floristic and structure of the community’s understory, composed of shrub-arboreal individuals with perimeter at breast height (PBH) lower than 15 cm and up to 1,30 m height. Correlation of phytosociological parameters with the physiography, previously investigated, was also studied. Twenty plots of 25 m² were used, where the botanical species, height and diameter at base height (DBH) of each individual were evaluated. Among the 39 species found the most important was Allophylus edulis (A.St.-Hil., Cambess. e A. Juss.) Radkl. (vacum), that showed the largest parametric values and plasticity to ground water regime. It was inferred that possibly, artificial drainage was promoting the access of moderated and weakly tolerant flood species in these areas, originally composed of very specific flora.

Flora epifítica vascular em três unidades vegetacionais do Rio Tibagi, Paraná, Brasil

Este trabalho teve como objetivo avaliar a composicao floristica dos epifitos vasculares ao longo do rio Tibagi, Parana, em 23 areas distribuidas em distintas altitudes, tipos climaticos e unidades vegetacionais. Foram analisadas as caracteristicas ecologicas e a distribuicao das especies ao longo do gradiente estabelecido de montante para jusante do rio. Os epifitos vasculares foram representados por 188 especies, pertencentes principalmente as familias Orchidaceae, Polypodiaceae e Bromeliaceae e ao grupo dos holoepifitos caracteristicos. As comunidades epifiticas do rio Tibagi foram enquadradas, de montante para jusante do rio, em duas unidades vegetacionais, floresta ombrofila mista e floresta estacional semidecidual, e na transicao entre ambas, o ecotono. Estas apresentam distintas riquezas e composicoes floristicas, o que ressalta sua importância na conservacao e manutencao da diversidade de epifitos no estado do Parana. A vegetacao do ecotono, situada na porcao intermediaria do rio, apresentou maior riqueza epifitica, o que se deve, provavelmente, ao contato entre as unidades vegetacionais, ao bom estado de conservacao das florestas e a presenca de corredeiras e cachoeiras.

Manejo dos resíduos da colheita de acácia-negra ( Acacia mearnsii De Wild) e a sustentabilidade do sítio.

Black wattles can grow on several environmental conditions being a fast growing and short life pioneer specie. This work was established on Acacia mearnsii De Wild commercial plantations, belonging to TANAGRO Co., in Piratini, Rio Grande do Sul, Brazil, growing on different soil types, with plants from the same origin. In each of the five-soil type, a treatment to evaluate black wattle growth in DBH and height, and above ground biomass was considered. Soils had their surface horizons characterized morphological, chemical and physically, and nutritional status were measured in every plant compartment, tannin yield in plant bark, amount of lignin and total extractives were determined in commercial stem wood. Neossolo Litolico eutrofico (Entisol) showed the greatest commercial stem volumes and Neossolo Litolico alico (Entisol) was the least productive, especially due to soil fertility differences, mainly P level, base saturation and aluminum saturation. The amount of macronutrients returned, keeping harvesting residues (branches and crown) on soil surface, was greater than the amount exported in commercial stem and bark, attesting its efficiency on soil reclaiming, if the residues are not burned. In most productive soils in volume of commercial stems, the amount of calcium and magnesium exported was greater than the amount returned to soil. The amount of tannin in black wattle bark was greater in plants growing in adverse soil conditions (shallow and stony soils).

Estructura de las principales especies arbóreas en el parque cruce caballero y su similitud floristica con areas de Argentina y de Brasil.

The present work aimed to study the fitossociologic structure and floristic similarity among seasonal and mixed forests of Argentina and Brazil. Cruce Caballero Park with 522 hectares where the method of multiple plots was adopted with (20 x 10 m). In each plot all individual tree of size equal or heigher than 5 cm diameter were registered, being measured the stem diameter and height into three environmental compartments, Haplorthox, Ustorthent and Udorthent. In Haplorthox, Araucaria angustifolia (Bertol.) Kuntze prevail at higher stratum and Sorocea bonplandii (Baill.) W.C.Burger, Lanj. & Boer , Cabralea canjerana (Vell.) Mart., Ocotea lancifolia Mez and Apuleia leiocarpa J.F.Macbr. follow it. In Ustorthent araucaria is absent and Gymnanthes concolor Mull.Arg. , Trichilia claussenii C.DC. , Apuleia leiocarpa, Pilocarpus pennatifolius Lem. and Sorocea bonplandii prevail. Aracuaria is scarce in Udorthent where Parapiptadenia rigida (Benth.) Brenan , Alchornea triplinervia Mull.Arg., Luehea divaricata Mart. , Erythrina falcata Benth. and Myrsine gardneriana A.DC. prevail. A comparative analysis shown Cruce Caballero more similar to seasonal forests than mixed araucaria forest from Brazil.

Efeitos de sistemas de preparo do solo na erosão e na produtividade da acácia-negra (Acacia mearnsii De Wild.).

Black wattle plantations are not always settled in soils adequate for the species sometimes due to land value or due to industry distance. Different soil tillage systems can improve soil conditions to plant growth, avoid erosion problems and reduce costs. In areas belonging to TANAGRO S.A. e SETA S.A., in two different counties, Piratini and Butia, RS, and two distinct soil types – litholic and red yellow podzolic – soil tillage systems with different levels of soil disturbance were tested in growing black wattle: planting in holes with no-tillage and planting after subsoiling with two, three and five shranks and harrowings. Plant height and DBH were taken annually, and after seven years samples of the trunk were obtained at six different positions for specific gravity analyses. Soils were characterized chemically and physically on their surface layers. Soil losses were greater where soil was prepared with a five-shrank-subsoiler, and they were measurable until 18 months after planting. These soil losses are very important for sustainable production of the litholic soil, constituted in around 80% of stones. Reduced tillage system, with planting holes opened manually and mechanically, did not decrease black wattle growth on both soils studied. However, plant growth increment at the initial stage was smaller on reduced tillage system, and this difference to the other tillage systems tested remained until 24 months after planting.

The Late Holocene upper montane cloud forest and high altitude grassland mosaic in the Serra da Igreja, Southern Brazil

Many soils of the highlands of Serra do Mar, as in other mountain ranges, have thick histic horizons that preserve high amounts of carbon. However, the age and constitution of the organic matter of these soils remain doubtful, with possible late Pleistocene or Holocene ages. This study was conducted in three profiles (two in grassland and one in forest) in Serra da Igreja highlands in the state of Paraná. We performed δ13C isotope analysis of organic matter in soil horizons to detect whether C3 or C4 plants dominated the past communities and 14C dating of the humin fraction to obtain the age of the studied horizons. C3 plants seem to have dominated the mountain ridges of Serra da Igreja since at least 3,000 years BP. Even though the Serra da Igreja may represents a landscape of high altitude grasslands in soils containing organic matter from the late Pleistocene, as reported elsewhere in Southern and Southeastern Brazil, our results indicate that the sites studied are at least from the beginning of the Late Holocene, when conditions of high moisture enabled the colonization/recolonization of the Serra da Igreja ridges by C3 plants. This is the period, often reported in the literature, when forests advanced onto grasslands and savannas.

Influência da posição na encosta na manifestação do caráter coeso em solos da formação Macacu, no estado do Rio de Janeiro

The cohesive nature of horizons of certain soils interferes directly with plant growth, by reducing the effective soil depth, plant root volume and seedling emergence, due to the decreased availability of water and air in the soil. This paper aimed to use soil physical characteristics to describe the cohesive character and the influence of the soil landscape position on two slopesof soils developed from sediments of the Macacu Formation in Itaborai, RJ, Brazil. The soils of both slopes were classified as Argissolo Amarelo distrocoeso tipico (Ultisol) in the upper position and as Latossolo Amarelo distrocoeso tipico (Oxisol) at the foot slope. The soil bulk density of the cohesive subsurface horizons reached 1.78 Mg m-3. Another evidence of the trendto show cohesive character was the great difference between soil physical propertiesofthe A horizon and the subsurface layers (BA and BW). In the soils at the foot slope position the moisture content, hydraulic conductivity, and available water content were higher. The expression of the cohesive character was stronger at the upper position of the landscape. The physical properties that best distinguished the soil samples in terms of landscape positions were bulk density and macroporosity for soils at the summits, and available water and total porosity for the foot slope. The soils at the bottom of the slope had higher water contents, which must have minimized the expression of the cohesive character. This study indicates the importance of developing more studies on different aspects of the degree of cohesion existing along a landscape, controlled primarily by water flows down the slope.

Vascular grassland plants of Tibagi River Spring, Ponta Grossa, Brazil

A systematic survey was carried out on wet grasslands found over Histosols at Upper Tibagi River basin, between Ponta Grossa and Palmeira municipalities, in the state of Parana, Brazil, place of high importance because of soil water retention capability and soil carbon pool composition. We provide a checklist containing 146 species, 96 genera and 42 plant families for the area. Families with higher species richness were Asteraceae (27 species; 21 genera), Poaceae (24; 16) and Cyperaceae (18; 6). Four species were classified as endangered or rare, and one as exotic. The specific richness in wet grassland environments at the state of Parana underlines the need for conservation efforts encompassing these formations.

Methane fluxes from waterlogged and drained Histosols of highland areas

Soil can be either source or sink of methane (CH4), depending on the balance between methanogenesis and methanotrophy, which are determined by pedological, climatic and management factors. The objective of this study was to assess the impact of drainage of a highland Haplic Histosol on CH4 fluxes. Field research was carried out in Ponta Grossa (Parana, Brazil) based on the measurement of CH4 fluxes by the static chamber method in natural and drained Histosol, over one year (17 sampling events). The natural Histosol showed net CH4 eflux, with rates varying from 238 µg m-2 h-1 CH4, in cool/cold periods, to 2,850 µg m-2 h-1 CH4, in warm/hot periods, resulting a cumulative emission of 116 kg ha-1 yr-1 CH4. In the opposite, the drained Histosol showed net influx of CH4 (-39 to -146 µg m-2 h-1), which resulted in a net consumption of 9 kg ha-1 yr-1 CH4. The main driving factors of CH4 consumption in the drained soil were the lowering of the water-table (on average -57 cm, vs -7 cm in natural soil) and the lower water content in the 0-10 cm layer (average of 5.5 kg kg-1, vs 9.9 kg kg-1 in natural soil). Although waterlogged Histosols of highland areas are regarded as CH4 sources, they fulfill fundamental functions in the ecosystem, such as the accumulation of organic carbon (581 Mg ha-1 C to a depth of 1 m) and water (8.6 million L ha-1 = 860 mm to a depth of 1 m). For this reason, these soils must not be drained as an alternative to mitigate CH4 emission, but effectively preserved.

Influence of Guadua paraguayana Döll on the structure and regeneration of a remaining forest at the high lands of Tibagi River, Paraná state.

As soon as the bamboo’s invasion was diagnosed in the alluvial floodplain of Tibagi’s river, Ponta Grossa-PR, the study started evaluating, through phytosociological study and indicators associated with the structure and functioning of the forest, the aggression and influence of the bamboo species on the structure and regeneration of a subtropical ombrophilous alluvial forest remnant. The phytosociological study was developed by an installation of sixteen plots (50m2) to inventory all the trees with CBH ≥ 15 cm and sixteen other plots (4m2) for studying the regeneration: individuals with up to 1.30 m high. The results show that the effect of G. paraguayana in species richness, mortality and number of trees, vitality of the remaining trees, abundance of vascular and nonvascular epiphytes, regeneration and in the incidence of radiation inside the plots, is very significant. But even though the changes caused by this bamboo compromise the regeneration dynamics of alluvial formations in the high Tibagi’s areas, the species is only an aggravating and not the cause of environmental degradation.