scholarly journals Distribution of Atta (Hymenoptera - Formicidae) in "terra-firme" rain forest of Central Amazonia: density, species composition and preliminary results on effects of forest fragmentation

1988 ◽  
Vol 18 (3-4) ◽  
pp. 309-315 ◽  
Author(s):  
Heraldo Luís de Vasconcelos
Keyword(s):  
Species Composition ◽  
Rain Forest ◽  
Abundant Species ◽  
Forest Fragments ◽  
Forest Fragment ◽  
Terra Firme ◽  
Atta Sexdens ◽  
Conservation Areas ◽  
Continuous Forest ◽  
Leaf Cutting

One hundred and fourteen hectares of a "terra-fiirme" rain forest 70 km north of Manaus, Amazonas, Brazil, were surveyed for leaf-cutting ant colonies (Atta spp). One half of this area was in isolated forest fragments (surrounded by pastures or second growth) of two sizes: 1 and 10 ha. The other half was in non-isolated fragments (connected to a large parch of forest) of the same sizes. Only two species occured in this forest: Atta sexdens sexdens L. and A. cepfhalotes L. The first was the most abundant species with a mean density of 0.35 colonies per ha. The mean density of A. cephalotes colonies was 0.03 per ha. The density of colonies was not significantly different between the isolated fragments and the continuous forest. Furthermore, the species composition did not change with isolation. However, pre-isolation data and long term monitoring are necessary to conclude that the isolation of a forest fragment has no effect upon Atta colonies. The non-uniform spatial distribution of Atta colonics within the "terra-firme" forest must be taken into account when selecting conservation areas in the Amazon, in order to preserve this important group of ants together with their native habitat.

Predation on exposed and leaf-rolling artificial caterpillars in tropical forests of Papua New Guinea

2012 ◽  
Vol 28 (4) ◽  
pp. 331-341 ◽  
Author(s):  
Katerina Tvardikova ◽  
Vojtech Novotny
Keyword(s):  
Natural Enemies ◽  
Rain Forest ◽  
Secondary Forest ◽  
Primary Forest ◽  
Secondary Forests ◽  
Forest Fragments ◽  
Leaf Rolling ◽  
Forest Fragment ◽  
Tropical Rain Forests ◽  
Rain Forests

Abstract:Although predation is generally seen as one of the key factors determining the abundance and composition of insect herbivore communities in tropical rain forests, quantitative estimates of predation pressure in rain-forest habitats remain rare. We compared incidence of attacks of different natural enemies on semi-concealed and exposed caterpillars (Lepidoptera) in lowland and montane tropical rain forests, using plasticine models of caterpillars. We recorded attacks on caterpillars in four habitats: primary forest, secondary forest and forest fragment in lowlands (200 m asl), and montane primary forest (1700 m asl). We used 300 exposed and 300 semi-concealed caterpillars daily, and conducted the experiment for 6 d in every habitat. Daily incidence of attacks was higher on exposed caterpillars (4.95%) than on semi-concealed (leaf-rolling) caterpillars (2.99%). Attack pressure of natural enemies differed also among habitats. In the lowlands, continuous primary and secondary forests had similar daily incidence of attacks (2.39% and 2.36%) which was however lower than that found in a primary forest fragment (4.62%). This difference was caused by higher incidence of attacks by birds, ants and wasps in the forest fragment. The most important predators were birds in montane rain forests (61.9% of identified attacks), but insect predators, mostly ants, in the lowlands (58.3% of identified attacks). These results suggest that rapid decrease in the abundance of ants with altitude may be compensated by increased importance of birds as predators in montane forests. Further, it suggests that small rain-forest fragments may suffer from disproportionately high pressure from natural enemies, with potentially serious consequences for survival of their herbivorous communities.

scholarly journals Ecology of phlebotomines (Diptera, Psychodidae) in rural foci of leishmaniasis in tropical Brazil

2012 ◽  
Vol 45 (6) ◽  
pp. 696-700 ◽  
Author(s):  
Clara Maria Lima Silva ◽  
Leandro Santos Moraes ◽  
Gustavo Almeida Brito ◽  
Ciro Libio Caldas dos Santos ◽  
José Manuel Macário Rebêlo
Keyword(s):  
Community Structure ◽  
Species Composition ◽  
Rain Forest ◽  
Abundant Species ◽  
Lutzomyia Longipalpis ◽  
Light Traps ◽  
Rural Villages ◽  
High Level ◽  
Santa Maria ◽  
Permutation Analysis

INTRODUCTION: This work aimed to study the community structure of sandflies, with regard to the richness, constancy, abundance, and monthly frequency of the species with a focus on the transmission of leishmaniasis. METHODS: The study was conducted in the rural villages of Bom Jardim and Santa Maria, situated on the edge of a tropical rain forest in the municipality of São Jose de Ribamar, Maranhão, Brazil. The phlebotomines were captured in the intradomiciles and peridomiciles of each village, with Centers for Disease Control (CDC) light traps set in 10 homes in each village, for 1 year, once a month, from 18h to 6h. RESULTS: We collected 1,378 individuals of 16 sandfly species. The capture success rate was higher in Bom Jardim (0.61 specimens/hour/trap) than that of Santa Maria (0.35/specimens/hour/trap). The sandflies were more abundant in the peridomiciles (86.1%) and in the rainy season (77%). Five species were considered constants (occurring in more than 50% of samples), 5 accessory (25%-50%), and 6 accidental (<25%). The most abundant species were Lutzomyia longipalpis (59.7%) and L whitmani (28%). The permutation analysis showed differences between the species composition of the villages and no separation between the intradomicile and peridomicile of each village. The species that most contributed to the dissimilarity between the light traps of the 2 villages were L. longipalpis, L. whitmani, and L. evandroi, contributing to 80.8% of the variation among groups. CONCLUSIONS: The high level of richness and abundance of species and the presence of competent vectors throughout the year and around houses justify the occurrence of leishmaniasis cases reported in the area.

The effects of fragmentation of an Australian tropical rain forest on populations and assemblages of small mammals

2001 ◽  
Vol 17 (2) ◽  
pp. 225-240 ◽  
Author(s):  
G. N. HARRINGTON ◽  
A. N. D. FREEMAN ◽  
F. H. J. CROME
Keyword(s):  
Home Range ◽  
Small Mammals ◽  
Rain Forest ◽  
Tropical Rain Forest ◽  
Agricultural Landscape ◽  
Forest Edge ◽  
Forest Fragments ◽  
Agricultural Matrix ◽  
Continuous Forest ◽  
The Matrix

Small mammals were trapped in four rain forest fragments (3, 8, 20 and 97 ha), in an agricultural landscape, and in comparable continuous tropical rain forest in north Queensland, Australia over 2 y. The most frequently captured species were four murid rodents. Melomys cervinipes were captured in similar numbers in both continuous and fragmented forest. This species achieves greatest abundance at forest edges and this study suggests that edges of fragments and edges of continuous forest will support similar densities. Abundance of Uromys caudimaculatus was positively correlated with size of fragment and peaked in continuous forest. This species had a home range larger than the smaller fragments and was thus disadvantaged but its ability to utilize the agricultural matrix between fragments mitigated the effect. Rattus leucopus and R. fuscipes were most abundant in fragments and continuous forest respectively but both species occurred in similar abundance in the 97-ha fragment. This suggests their population size is related to habitat rather than competitive exclusion as previously postulated. Ordination of the populations of the nine most commonly captured mammals, separated the fragment and continuous sites but placed the largest fragment closest to the continuous sites. The contrasting response of the two Rattus spp. was the primary influence on the ordination. Second in importance was Trichosurus vulpecula, a folivorous possum, which was absent from the continuous sites. The fragments may have had more nutrient-rich, pioneer tree foliage than continuous forest. Isoodon macrourus, Perameles nasuta, Antechinus godmani and Uromys hadrourus also showed positive or negative response to fragmentation. Species utilizing the matrix between forest fragments and species adapted to forest edge are advantaged by the fragmentation process whereas forest specialists tend to extinction in fragments, particularly where the home range of the animal is not many times smaller than the fragment.

scholarly journals Anurofauna of an Atlantic Rainforest fragment and its surroundings in Northern Rio de Janeiro State, Brazil

2010 ◽  
Vol 70 (3 suppl) ◽  
pp. 871-877 ◽  
Author(s):  
M Almeida-Gomes ◽  
M Almeida-Santos ◽  
P Goyannes-Araújo ◽  
VNT Borges-Júnior ◽  
D Vrcibradic ◽  
...  
Keyword(s):  
Rio De Janeiro ◽  
Abundant Species ◽  
The State ◽  
Forest Fragments ◽  
Forest Fragment ◽  
The North ◽  
Surrounding Matrix ◽  
Plot Sampling ◽  
Northern Portion ◽  
Janeiro State

We carried out a study on the anurofaunal community from an Atlantic Forest fragment (Monte Verde mountains) and the surrounding area in Cambuci municipality, Rio de Janeiro State, Brazil, which constitutes one of the largest fragments remaining in the largely deforested landscape of the northern portion of the State. We combined three sampling methods: plot sampling, transects and pit-fall traps. We recorded twenty species of amphibians, of which only eleven were found within the forest fragment (and five of these also occurred in the surrounding matrix). Two of the species recorded in the present study (Crossodactylus sp. and Ischnocnema cf. parva) may represent undescribed taxa. Our records expand the distribution range of one species (Scinax trapicheiroi) to the north, and fill a geographic distribution gap for another one (Ischnocnema oea). The estimated overall density of frogs living in the leaf litter of the fragment (based on results of plot sampling) was 3.1 individuals/100 m², with Haddadus binotatus being the most abundant species (2.4 individuals/100 m²). Comparisons of our data with those of other studies suggest that anuran communities in forest fragments ca. 1,000 ha or smaller may be severely limited in their richness, and often include a large proportion of species tolerant to open areas, such as many hylids. Our results show the importance of increasing knowledge about the anurofaunal community of the northern portion of the State of Rio de Janeiro and preserve the forest remnants that still exist in the region.

Gap-crossing by Wood Thrushes (Hylocichla mustelina)in a fragmented landscape

2011 ◽  
Vol 89 (11) ◽  
pp. 1091-1097 ◽  
Author(s):  
T. MacIntosh ◽  
B.J.M. Stutchbury ◽  
M.L. Evans
Keyword(s):  
Radio Telemetry ◽  
Fragmented Landscape ◽  
Forest Fragments ◽  
Forest Fragment ◽  
Hylocichla Mustelina ◽  
Continuous Forest ◽  
Migratory Songbirds ◽  
Gap Crossing ◽  
Wood Thrushes ◽  
Gap Width

We used radio-telemetry to study the movement patterns of Wood Thrushes ( Hylocichla mustelina (J.F. Gmelin, 1789)) occupying small forest fragments (<5 ha) to examine gap-crossing between fragments and edge use within fragments. We found that 82% (8/11) of males and 33% (2/6) of females made at least one foray off of its resident forest fragment and we documented a total of 26 off-fragment forays (n = 79 h tracking). Males spent, on average, 23.5% of their time off their fragment, while females were gone 12.8% of the time tracked. Most forays were >150 m in distance and foray rate to adjacent fragments declined with increasing gap width. Males on fragments spent more time off their territory (23.5%) and traveled farther (392 m) than males occupying territories within a continuous forest (4.8% and 99 m, respectively). In fragments, 10 out of 17 individuals spent >80% of their time within 20 m of the fragment edge and edge use was significantly more than expected based on the amount of edge available in each fragment. This study adds to the growing evidence for migratory songbirds that during the breeding season, forest fragmentation may increase rather than impede daily movements.

scholarly journals Bryophytes in fragments of Terra Firme forest on the great curve of the Xingu River, Pará state, Brazil 1 Part of Master's Dissertation of the first author.

2015 ◽  
Vol 75 (3 suppl 1) ◽  
pp. 238-249 ◽  
Author(s):  
ACC. Pantoja ◽  
AL. Ilkiu-Borges ◽  
ACC. Tavares-Martins ◽  
ET. Garcia
Keyword(s):  
Species Composition ◽  
Tropical Forest ◽  
Environmental Changes ◽  
Forest Fragments ◽  
Habitat Conditions ◽  
Terra Firme ◽  
Xingu River ◽  
Microclimatic Conditions ◽  
Terra Firme Forest ◽  
Made In

Abstract Microclimatic conditions of tropical forest favour the high richness of bryophytes, which by being sensitive to environmental changes, are important indicators of habitat conditions. The aim of this study was to determine the richness and species composition of the bryophyte flora in fragments of terra firme forest on the great curve of the Xingu River, Pará state, Brazil. The collections were made in August and September 2012 in 14 fragments, in which were installed two plots per fragment, one at the edge and one inside, measuring 10 × 10 m each. The results showed 77 species in 45 genera and 18 families. Lejeunea setiloba Spruce and Marchesinia brachiata (Sw.) Schiffn. are new records for Pará state. The richness families in this study were the ones typically found in tropical forest surveys. A high richness of rare species in comparison to common ones, a pattern usually observed for plants in tropical forests was not reported in this study, probably due to historical fragmentation and disturbance in the area. The richness and species composition were determined mainly by the physiognomic characteristics of the studied forest fragments.

The influence of forest fragmentation on clonal diversity and genetic structure in Heliconia angusta, an endemic understorey herb of the Brazilian Atlantic rain forest

2014 ◽  
Vol 30 (3) ◽  
pp. 199-208 ◽  
Author(s):  
Katharina Stein ◽  
Christoph Rosche ◽  
Heidi Hirsch ◽  
Anke Kindermann ◽  
Julia Köhler ◽  
...  
Keyword(s):  
Genetic Diversity ◽  
Rain Forest ◽  
Size Range ◽  
Clonal Diversity ◽  
Atlantic Rain Forest ◽  
Site Conditions ◽  
Forest Fragments ◽  
Negative Effects ◽  
Continuous Forest ◽  
Genetic Diversity And Structure

Abstract:Fragmented populations are usually exposed to the negative effects of reduced gene flow, genetic drift and population differentiation. These effects result in the collective loss of genetic variation, thereby reducing the probability of population adaptation to new environmental conditions and increasing the risk of extinction. Forest fragments commonly exhibit suboptimal site conditions, which can result in enhanced clonal reproduction, and a potential reduction in clonal diversity due to increased selfing and inbreeding depression. The clonal diversity, genetic diversity and structure of Heliconia angusta (Heliconiaceae) were assessed using AFLP-markers. We analysed six patches in the continuous forest (Atlantic rain forest, State of Rio de Janeiro) and eight patches (155 leaf samples in total) in five nearby forest fragments (age of oldest fragment: c. 50 y; size range: < 5–100 ha). Clonal diversity (Pd) of patches was slightly, yet significantly, lower in forest fragments compared with continuous forest. Measures of genetic diversity of patches in forest fragments did not differ from those in the continuous forest. A STRUCTURE analysis did not show any clear clustering of patches in the continuous forest and forest fragments. Our results suggest that H. angusta has not yet suffered from the anticipated negative effects of fragmentation.

scholarly journals Structure and tree species composition of forest fringe of a forest fragment in an oil palm plantation at Suai, Sarawak, Malaysian Borneo

2021 ◽  
Vol 22 (7) ◽  
Author(s):  
Claudia Lennya Jana ◽  
ISMAIL JUSOH
Keyword(s):  
Species Composition ◽  
Oil Palm ◽  
Tree Species ◽  
Forest Fragments ◽  
Forest Fragment ◽  
Tree Species Composition ◽  
Oil Palm Plantation ◽  
Strong Winds ◽  
Fragmented Forests ◽  
Forest Fringe

Abstract. Jana CL, Jusoh I. 2021. Structure and Tree Species Composition of Forest Fringe of A Forest Fragment in an Oil Palm Plantation at Suai, Sarawak, Malaysian Borne. Biodiversitas 22: 3013-3019. Forest fragments in oil palm plantations are remnants of the original forest tract with various sizes and shapes after clearing forested lands for crops and roads. Fragmented forests usually created forest fringe or edge habitats that differ in light intensity, temperature, humidity, heavy rainfall, and strong winds from its core. The study was aimed to determine the structure and tree species composition of the forest fringe of a fragmented forest in an oil palm plantation Suai, Sarawak. This study established a total of 24 sampling plots within the forest fringe. Tree enumeration and species identification were conducted in all sampling plots to all trees with a diameter at breast height 5 cm and higher.  A total of 59 families comprised of 274 species and 948 trees individuals were recorded. The aboveground biomass stand at 260 Mg ha?¹. Species Elateriospermum tapos was predominant, and family Dipterocarpaceace dominated the forest fringe.   Based on the calculated indices, species diversity and richness were considered high, while the dispersion of individual trees was random but unevenly distributed. Natural regeneration in the forest fringe is sustainable. The forest structure and species composition are intact, and without significant disturbance, the whole forest fragment is self-sustain.

Edge effects on litterfall mass and nutrient concentrations in forest fragments in central Amazonia

2000 ◽  
Vol 16 (6) ◽  
pp. 853-863 ◽  
Author(s):  
NIGEL C. SIZER ◽  
EDMUND V. J. TANNER ◽  
ISOLDE D. KOSSMANN FERRAZ
Keyword(s):  
Rain Forest ◽  
Forest Edge ◽  
Dry Season ◽  
Nutrient Concentrations ◽  
Forest Fragments ◽  
Forest Edges ◽  
Forest Fragment ◽  
Wet Season ◽  
Lowland Rain Forest ◽  
Central Amazonia

Forest edges bordering on pasture were created by cutting and burning the surrounding Amazonian lowland rain forest in the dry season (June) of 1990. Litterfall was measured for 3.5 y along transects 10, 50, 100 and 250-m into the forest from the forest edge. Litterfall along the 10-m transects increased by up to 2.5 times that on spatial controls (250-m transects) in the dry season in which the edge was created. In the second dry season after edge creation litterfall at 10-m was lower than on controls, after which it returned to control rates in the second wet season, 1.5 y after edge creation. Litterfall 50-m into the forest was less affected; there was a smaller rise in the dry season in which the edge was cut, and no significant effects after that. At 100-m there was no effect of edge creation on litterfall. Phosphorus concentrations in litterfall were elevated along 10-m transects, 10–12 wk after edge creation, possibly because of reduced retranslocation prior to abscission. The changes in litterfall described here are inextricably linked to the biomass collapse, which occurs near forest-fragment edges in the same area.

Antibiotic-producing bacteria associated with the nests of the leaf-cutting ant Atta sexdens rubropilosa

Planta Medica ◽  
2015 ◽  
Vol 81 (11) ◽  
Author(s):  
EA Silva-Junior ◽  
CR Paludo ◽  
FS Nascimento ◽  
CR Currie ◽  
J Clardy ◽  
...  
Keyword(s):  
Atta Sexdens ◽  
Atta Sexdens Rubropilosa ◽  
Leaf Cutting
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