scholarly journals Floristic composition of two wetland forests in Araguaian Plain, State of Tocantins, Brazil, and comparison with other areas

2008 ◽  
Vol 32 (1) ◽  
pp. 129-141 ◽  
Author(s):  
Sebastião Venâncio Martins ◽  
Elizabeth Rodrigues Brito ◽  
Ary Teixeira de Oliveira Filho ◽  
Alexandre Francisco da Silva ◽  
Elias Silva

Seasonally inundated native forest fragments ("ipucas") located in natural landform depression swales of the Araguaian Plain are currently under land use pressure. Their composition needs to be better understood to guarantee their protection. This comparative study of fragments under different land use conditions was carried out at Lago Verde Farm, Lagoa da Confusão,Tocantins, Brazil. The location coordinates are UTM 643586 and 644060 East and 8792795 and 8799167 North. This study aimed to first analyze and compare the floristic composition of two seasonally inundated forest fragments of approximately one hectare each. The first is located in an intact (without human intervention) Gramineous-Woody Savanna region and the second in a rice cultivation region. The floristic composition of both fragments was then compared to that of other wetland forests located in the Northern, Central Western and Southeastern regions of Brazil.All the floristic compositions are affected by seasonal flooding and soil water saturation. The floristic inventory used a census method that sampled all trees and shrubs with perimeter at 1.30 m from soil (PAP) = 15cm; 665 individuals, 33 families and 49 species were recorded for the intact region and 807 individuals, 35 families and 70 species for the altered region fragment. The values of H' = 0.806 (Shannon-Weaver) and J = 3.44 nats /individual (equability) for the fragment in the region affected by rice cultivation are considered high compared to the intact region fragment values (H' = 0.761 and J = 2.97). Families contributing to floristic richness in the altered region fragment were Fabaceae (9 species), Vochysiaceae (6) and Annonaceae (4). In the intact region fragment, Fabaceae also presented the largest number of species (8) followed by Arecaceae, Chrysobalanaceae and Vochysiaceae (3 each). When comparing the forests from various regions in Brazil, floristic similarity was found to be small. Greater similarity was found when indices for the two Lagoa da Confusão fragments were compared to riparian forests located in the Federal District of Brasilia.

2018 ◽  
Vol 18 (4) ◽  
Author(s):  
Ivanete Teresinha Mallmann ◽  
Vinícius Leão da Silva ◽  
Jairo Lizandro Schmitt

Abstract: The Araucaria Forest is a unique plant formation, practically restricted to the Atlantic Forest biome, in the South and Southeast of Brazil. It is immensely fragmented and its area is reduced to a minimum fraction, from 13 to 2% of the original area, due to intense anthropic exploitation. Our study evaluated the richness and floristic composition of ferns and lycophytes within three Araucaria forest fragments, in Rio Grande do Sul, Brazil. For the floristic inventory, a parcel of 1 ha (100x100m) was demarcated inside three fragments, which were classified by size: large (246 ha - H1LF), medium (57 ha - H2MF) and small (5.2 ha - H3SF). Occurring species life forms and preferential substrates up to 4 meters above ground were recorded. In total, 55 species were catalogued, only two of which were lycophytes, distributed in 32 genera and 17 families. Considering the area of fragments, the recorded species richness has decreased, presenting greater numbers in H1LF (48), followed by H2MF (33), and H3SF (29). In the three sites, terrestrial substrate and the hemicryptophyte species life form predominated. We observed that one hectare of a larger forest fragment presented 65% more species than that of a smaller one, considering that the smaller fragment total area represents only 2% of the larger forest's area. On the other hand, one hectare of the smaller fragment contributed 17% to fern and lycophyte species conservation occurring in Brazilian Araucaria Forests, and 8% to the state of Rio Grande do Sul's total richness. The diverse heterogeneity and species composition grants floristic identity to each of the studied forest interiors. Our results highlight the need to include the botanical parameters here analyzed in management, conservation degree evaluation, and maintenance of Araucaria Forests plant biodiversity.


2017 ◽  
Vol 41 (4) ◽  
pp. 413-427 ◽  
Author(s):  
Leandro Campos Pinto ◽  
Carlos Rogério de Mello ◽  
Lloyd Darrell Norton ◽  
Sérgio Henrique Godinho Silva ◽  
Luís Renato Silva Taveira ◽  
...  

ABSTRACT In Brazil, the Mantiqueira Range, southeastern region, shelters the last remnants of the ecologically important Upper Montane Tropical Forest. since extensive exploration that has been taking place in this biome for decades, the influence of land-use changes on hydropedology in these areas must be investigated once major land-use changes have been observed. This study aims to evaluate the land-use influence on soil drainable porosity (SDP) in a headwater watershed located in the Mantiqueira Range region, and to validate the proposed methods based on micromorphological and hydrological indicators. The native vegetation of the study area is Atlantic forest that occupies 62% of the area, and the remaining 38% has been used for pasture. Thirty nine combinations of environmental variables were tested, each one generating a map for predicting SDP. The performance of the spatial prediction of SDP was assessed using 20% of the data from the total number of samples collected throughout the watershed. The least values of SDP are due to the process of removal of native forest and replacement by pasture. Areas with high to moderate SDP are associated with native forest fragments demonstrating the effects of the Atlantic Forest on the water infiltration and groundwater recharge processes, given by the greater contribution of baseflow in a forested catchment located within the studied watershed. The analysis of soil micromorphological images provided useful supporting information on the soil porosity system and along with hydrological properties of the watershed helped understand the SDP behavior on subsurface and groundwater storage capacity.


Rodriguésia ◽  
2014 ◽  
Vol 65 (1) ◽  
pp. 21-33 ◽  
Author(s):  
Marcelo Brilhante de Medeiros ◽  
Bruno Machado Teles Walter ◽  
Washington Luis Oliveira

This work describes the woody layer composition and structure in two seasonal forest fragments in the Tocantins river basin and compares them to other remnants of this forest physiognomy in Brazil. The survey was carried out by using 17 plot samples (20 × 50 m) located in Palmeirópolis, state of Tocantins, and in Minaçú, state of Goiás. All woody individuals showing diameters > 5 cm, at 1.30 cm above ground level, were recorded. The higher floristic similarity of these forest remnants compared with other closer seasonal forests did not show a distinct pattern. The floristic composition was more similar to that of a deciduous seasonal forest in the Paranã valley, and more dissimilar to other forests in this same valley. This result and a higher dissimilarity related to the southern forests in Goiás suggest that the forest fragments showed a floristic composition and structure typical of lowland seasonal forests in the Tocantins river basin. The results also indicated that the forest fragments have distinct floristic compositions with a relatively similar structure and diversity.


2011 ◽  
Vol 261 (11) ◽  
pp. 2075-2080 ◽  
Author(s):  
Paulo Henrique Muller da Silva ◽  
Fabio Poggiani ◽  
Alexandre Magno Sebbenn ◽  
Edson Seizo Mori

2013 ◽  
Vol 22 (1) ◽  
pp. 6-12 ◽  
Author(s):  
Gustavo Seron Sanches ◽  
Thiago Fernandes Martins ◽  
Ileyne Tenório Lopes ◽  
Luís Flávio da Silva Costa ◽  
Pablo Henrique Nunes ◽  
...  

In the present study, we report tick infestations on wild birds in plots of the Atlantic Forest reforested fragments with native species and plots reforested with Eucalyptus tereticornis in the municipality of Rio Claro, State of Sao Paulo, Brazil. A total of 256 birds were captured: 137 individuals of 33 species, in planted native forest; and 128 individuals of 37 species, in planted Eucalyptus tereticornis forest. Nymphs of two tick species were found on the birds: Amblyomma calcaratumand Amblyomma longirostre, the former was more abundant in the fragments reforested with Atlantic forest native species, and the latter in the fragment reforested with E. tereticornis. New host records were presented for A. calcaratum.


2009 ◽  
Vol 69 (2) ◽  
pp. 231-240 ◽  
Author(s):  
MV. Cianciaruso ◽  
MA. Batalha

In South America, the largest seasonal savanna region is the Brazilian cerrado. Our aim was to study temporal changes in some community descriptors, such as floristic composition, richness, species density, plant density, and cylindrical volume, in a seasonal cerrado, comparing it to a nearby hyperseasonal cerrado. In four different seasons, we placed randomly ten 1 m² quadrats in each vegetation form and sampled all the vascular plants. Seasonal changes in floristic composition, species density, and plant density were less pronounced in the seasonal than in the hyperseasonal cerrado. Floristic similarity between the vegetation forms was lower when the hyperseasonal cerrado was waterlogged. Richness and species density were higher in the seasonal cerrado, which reached its biomass peak at mid rainy season. The hyperseasonal cerrado, in turn, reached its biomass peak at early rainy season and, despite the waterlogging, maintained it until late rainy season. In the hyperseasonal cerrado, waterlogging acts as an environmental filter restricting the number of cerrado species able to withstand it. The seasonal cerrado community was more stable than the hyperseasonal one. Our results corroborated the idea that changes in the environmental filters will affect floristic composition and community structure in savannas.


2018 ◽  
Vol 18 (11) ◽  
pp. 2859-2876 ◽  
Author(s):  
Nguyen Van Khanh Triet ◽  
Nguyen Viet Dung ◽  
Bruno Merz ◽  
Heiko Apel

Abstract. Flooding is an imminent natural hazard threatening most river deltas, e.g. the Mekong Delta. An appropriate flood management is thus required for a sustainable development of the often densely populated regions. Recently, the traditional event-based hazard control shifted towards a risk management approach in many regions, driven by intensive research leading to new legal regulation on flood management. However, a large-scale flood risk assessment does not exist for the Mekong Delta. Particularly, flood risk to paddy rice cultivation, the most important economic activity in the delta, has not been performed yet. Therefore, the present study was developed to provide the very first insight into delta-scale flood damages and risks to rice cultivation. The flood hazard was quantified by probabilistic flood hazard maps of the whole delta using a bivariate extreme value statistics, synthetic flood hydrographs, and a large-scale hydraulic model. The flood risk to paddy rice was then quantified considering cropping calendars, rice phenology, and harvest times based on a time series of enhanced vegetation index (EVI) derived from MODIS satellite data, and a published rice flood damage function. The proposed concept provided flood risk maps to paddy rice for the Mekong Delta in terms of expected annual damage. The presented concept can be used as a blueprint for regions facing similar problems due to its generic approach. Furthermore, the changes in flood risk to paddy rice caused by changes in land use currently under discussion in the Mekong Delta were estimated. Two land-use scenarios either intensifying or reducing rice cropping were considered, and the changes in risk were presented in spatially explicit flood risk maps. The basic risk maps could serve as guidance for the authorities to develop spatially explicit flood management and mitigation plans for the delta. The land-use change risk maps could further be used for adaptive risk management plans and as a basis for a cost–benefit of the discussed land-use change scenarios. Additionally, the damage and risks maps may support the recently initiated agricultural insurance programme in Vietnam.


2018 ◽  
Vol 130 (1) ◽  
pp. 112 ◽  
Author(s):  
Alison R. Styring ◽  
Joanes Unggang ◽  
Alex Jukie ◽  
Ollince Tateh ◽  
Nyegang Megom ◽  
...  

2014 ◽  
Vol 38 (2) ◽  
pp. 656-668 ◽  
Author(s):  
Karina Hacke Ribeiro ◽  
Nerilde Favaretto ◽  
Jeferson Dieckow ◽  
Luiz Cláudio de Paula Souza ◽  
Jean Paolo Gomes Minella ◽  
...  

Water degradation is strongly related to agricultural activity. The aim of this study was to evaluate the influence of land use and some environmental components on surface water quality in the Campestre catchment, located in Colombo, state of Parana, Brazil. Physical and chemical attributes were analyzed (total nitrogen, ammonium, nitrate, total phosphorus, electrical conductivity, pH, temperature, turbidity, total solids, biological oxygen demand, chemical oxygen demand and dissolved oxygen). Monthly samples of the river water were taken over one year at eight monitoring sites, distributed over three sub-basins. Overall, water quality was worse in the sub-basin with a higher percentage of agriculture, and was also affected by a lower percentage of native forest and permanent preservation area, and a larger drainage area. Water quality was also negatively affected by the presence of agriculture in the riparian zone. In the summer season, probably due to higher rainfall and intensive soil use, a higher concentration of total nitrogen and particulate nitrogen was observed, as well as higher electrical conductivity, pH and turbidity. All attributes, except for total phosphorus, were in compliance with Brazilian Conama Resolution Nº 357/2005 for freshwater class 1. However, it should be noted that these results referred to the base flow and did not represent a discharge condition since most of the water samples were not collected at or near the rainfall event.


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