Effects of anthropogenic environmental changes on amphibian diversity in the rain forests of eastern Madagascar

2002 ◽  
Vol 18 (5) ◽  
pp. 725-742 ◽  
Author(s):  
Denis Vallan
Keyword(s):  
Rain Forest ◽  
Environmental Changes ◽  
Rice Fields ◽  
Population Increase ◽  
Species Number ◽  
Secondary Forests ◽  
Resource Exploitation ◽  
Rain Forests ◽  
Natural Habitats ◽  
Amphibian Species

Madagascar has one of the world's highest rates of human population increase, which is coupled with an increase of resource exploitation, particularly food and firewood. Forests are cleared and converted to rice fields or plantations (mainly Eucalyptus or pine). How does deforestation affect the amphibian diversity of the original biotope, the rain forest? To answer this question, the amphibian fauna of intact rain forests was compared with that of secondary forests, Eucalyptus plantations and rice fields. The main consequence of rain forest disturbance was loss of amphibian species. Compared with an intact forest, species richness in secondary forests, Eucalyptus plantations and rice fields were 54%, 46% and 12%, respectively. Species number and individual density increased with increasing structural complexity of the habitat and the presence of water bodies. The reproductive strategy of the species could be decisive for the presence or absence of single species in different habitats. With increasing degradation the percentage of species spawning in water increased. Correspondingly, Hyperoliidae and Raninae were characteristic of degraded habitats, whereas Microhylidae and Mantellinae were representative of natural habitats.

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 The orthopterans of the rice agroecosystem in western Lomellina (Lombardy, Italy)

2018 ◽  
Vol 6 ◽  
pp. e24203 ◽  
Author(s):  
Davide Giuliano ◽  
Giuseppe Bogliani
Keyword(s):  
Environmental Changes ◽  
Rice Fields ◽  
Suitable Habitat ◽  
Natural Habitats ◽  
Dispersal Capacity ◽  
Habitat Specificity ◽  
High Dispersal ◽  
Surrogate Habitat ◽  
Taxonomic Groups ◽  
Habitat Specialist Species

Rice fields represent a valuable surrogate habitat for many wetland species, playing an important role for biodiversity conservation in human-managed landscapes. Despite the fact that several taxonomic groups have been thoroughly investigated in this agroecosystem, little is known about the orthopteran fauna which lives in and around rice paddies, especially in Europe. In this paper, we provide a first description of the orthopteran assemblages hosted in the rice agroecosystems of northern Italy, trying to evaluate their conservation value through an analysis of species ecological traits (habitat specificity and dispersal capacity). During field samplings in summer 2016, we detected 25 orthopteran species. The 24% of the community was composed by habitat specialist species and the 56% of the sampled taxa was characterised by high dispersal capacities. Rice fields are an extremely dynamic ecosystem, characterised by the continuous succession of flooding and drying periods and conditioned by many other farming activities. Consequently, the orthopteran fauna in rice crops is mainly composed of species well adapted to sudden environmental changes. On the other hand, rice fields represent a particular biotope, providing a suitable habitat especially for hygrophilous species, which are otherwise restricted to scattered marsh areas. In order to preserve orthopteran diversity in rice agroecosystems, sustainable farming practices should be applied, especially by preserving and restoring marginal semi-natural habitats, by reducing grass management intensity on paddy banks and by discouraging rice cultivation in dry soils.

Ants accelerate litter decomposition in a Costa Rican lowland tropical rain forest

2012 ◽  
Vol 28 (5) ◽  
pp. 437-443 ◽  
Author(s):  
Terrence P. McGlynn ◽  
Evan K. Poirson
Keyword(s):  
Mass Loss ◽  
Leaf Litter ◽  
Litter Decomposition ◽  
Rain Forest ◽  
Costa Rican ◽  
Tropical Rain Forests ◽  
Rain Forests ◽  
Food Web Structure ◽  
Litter Bags ◽  
Lowland Rain Forest

Abstract:The decomposition of leaf litter is governed, in part, by litter invertebrates. In tropical rain forests, ants are dominant predators in the leaf litter and may alter litter decomposition through the action of a top-down control of food web structure. The role of ants in litter decomposition was investigated in a Costa Rican lowland rain forest with two experiments. In a mesocosm experiment, we manipulated ant presence in 50 ambient leaf-litter mesocosms. In a litterbag gradient experiment, Cecropia obtusifolia litter was used to measure decomposition rate constants across gradients in nutrients, ant density and richness, with 27 separate litterbag treatments for total arthropod exclusion or partial arthropod exclusion. After 2 mo, mass loss in mesocosms containing ants was 30.9%, significantly greater than the 23.5% mass loss in mesocosms without ants. In the litter bags with all arthropods excluded, decomposition was best accounted by the carbon: phosphorus content of soil (r2 = 0.41). In litter bags permitting smaller arthropods but excluding ants, decomposition was best explained by the local biomass of ants in the vicinity of the litter bags (r2 = 0.50). Once the microarthropod prey of ants are permitted to enter litterbags, the biomass of ants near the litterbags overtakes soil chemistry as the regulator of decomposition. In concert, these results support a working hypothesis that litter-dwelling ants are responsible for accelerating litter decomposition in lowland tropical rain forests.

scholarly journals Resilience of tropical rain forests: tree community reassembly in secondary forests

2009 ◽  
Vol 12 (5) ◽  
pp. 385-394 ◽  
Author(s):  
Natalia Norden ◽  
Robin L. Chazdon ◽  
Anne Chao ◽  
Yi-Huei Jiang ◽  
Braulio Vílchez-Alvarado
Keyword(s):  
Secondary Forests ◽  
Tropical Rain Forests ◽  
Rain Forests ◽  
Tree Community ◽  
Community Reassembly

Seed mass and light requirements for regeneration in Southeast Asian rain forest

1995 ◽  
Vol 73 (6) ◽  
pp. 817-826 ◽  
Author(s):  
D. J. Metcalfe ◽  
P. J. Grubb
Keyword(s):  
Phylogenetic Analysis ◽  
Rain Forest ◽  
Secondary Forest ◽  
Seed Mass ◽  
Primary Forest ◽  
Secondary Forests ◽  
Light Requirement ◽  
Lowland Rain Forest ◽  
Light Requirements ◽  
Shade Tolerant Species

Seed mass values are given for 140 species of primary lowland rain forest and associated secondary forests in Singapore. Among shade-tolerant species of primary forest there is a trend for a decrease in mean seed mass with tall trees > woody climbers > small trees > shrubs > herbs; the differences between tall trees and small trees or shrubs or herbs, and between herbs and small trees or woody climbers are significant. There are a few light-demanding herbs or shrubs in the primary forest; among small trees, light demanders have significantly lower seed mass values than shade tolerators. In 9 out of 13 comparisons within taxa including both shade tolerants and light demanders the former had appreciably larger seeds than the latter. Two out of 13 comparisons involved very small seeded shade tolerators, and one a notably large-seed light demander. Many shade-tolerant herbs, shrubs, and trees have seed mass values much smaller than those of trees of secondary forest conventionally regarded as small seeded, and exploit moist, litter-free sites, e.g., steep microslopes. The trees of secondary forests on degraded soils do not differ significantly in seed mass from those on nondegraded soils. Key words: seed mass, light requirement, regeneration, tropical rain forest, phylogenetic analysis.

scholarly journals Impatiens balsamina (garden balsam).

2020 ◽  
Author(s):  
Julissa Rojas-Sandoval
Keyword(s):  
The Philippines ◽  
Forest Understory ◽  
Secondary Forests ◽  
Native Plant ◽  
Tropical Africa ◽  
Natural Habitats ◽  
Native Plant Species ◽  
Impatiens Balsamina ◽  
Annual Herb ◽  
The Caribbean

Abstract Impatiens balsamina is an annual herb thought to be native to India and Myanmar. It has been widely introduced outside of its native range as an ornamental to Europe, Asia, the Americas, Oceania and some parts of tropical Africa. It has escaped from cultivation and become naturalized in disturbed sites and semi-natural habitats including secondary forests and forest edges. It spreads by seed and also vegetatively by stem fragments and can form dense stands in forest understory inhibiting germination and the establishment of seedlings, displacing native plant species. It is thought to be invasive to many tropical and subtropical islands in Oceania and the Caribbean as well as Costa Rica, Peru, the Galapagos Islands, the Philippines and parts of India.

Shrimp abundance and habitat relationships in tropical rain-forest streams, Sarawak, Borneo

2003 ◽  
Vol 19 (4) ◽  
pp. 387-395 ◽  
Author(s):  
Tomoya Iwata ◽  
Mikio Inoue ◽  
Shigeru Nakano ◽  
Hitoshi Miyasaka ◽  
Atsushi Doi ◽  
...  
Keyword(s):  
Rain Forest ◽  
Tropical Rain Forest ◽  
Secondary Forest ◽  
High Water ◽  
Water Velocity ◽  
Primary Forest ◽  
Microhabitat Use ◽  
Secondary Forests ◽  
Habitat Differences ◽  
Forest Streams

Microhabitat use and habitat-abundance relationships of four freshwater shrimps, Atyopsis moluccensis, Macrobrachium pilimanus, Macrobrachium trompii and Macrobrachium neglectum, were surveyed in tropical streams running through primary and secondary forests in Borneo, East Malaysia. Underwater observations revealed that A. moluccensis preferred relatively high water velocity and a boulder substrate. Macrobrachium pilimanus also preferred high water velocity and a cobble substrate, whereas M. trompii occupied stream margins with slow current and fine substrates (from POM (particulate organic matter) to pebbles). In contrast, M. neglectum was distributed relatively evenly through the stream channel. The abundance of A. moluccensis, M. pilimanus and M. trompii in the stream reaches was best explained by the abundance of boulders, cobbles and POM, respectively, suggesting that the amount of preferred microhabitat is an important factor affecting shrimp abundances in the tropical rain-forest streams. The primary-forest reaches were dominated by coarse substrates, such as cobbles and boulders, while a great proportion of the streambeds in the secondary-forest reaches were covered with sand. Owing probably to such habitat differences, the abundance of both A. moluccensis and M. pilimanus, which preferred coarse substrates, was less in the secondary- than in the primary-forest reaches. These suggested that loss of preferred habitat, namely decreased coarse substrate availability, by sedimentation resulting from riparian deforestation had altered the shrimp assemblage structures.

scholarly journals LINGKUNGAN VEGETASI SITUS PERCANDIAN PADANG LAWAS DAN TUMBUHAN BALAKA

2011 ◽  
Vol 31 (1) ◽  
pp. 31-44
Author(s):  
Arfian Arfian
Keyword(s):  
Rain Forest ◽  
Tropical Rain Forest ◽  
Wild Plant ◽  
Tropical Rain Forests ◽  
Rain Forests ◽  
Open Spaces ◽  
Lowland Tropical Rain Forest ◽  
Plant Families ◽  
High Level

Based on the results of research on the vegetation around Padang Lawas Temples, Padang Lawas Regency, North Sumatera Province, can be known that Padang Lawas Temple sites are located in vegetation environment of lowland tropical rain forest with a high level diversity of plant families, one of those plant families is Euphorbiaceae with one of its species, Phylanthus emlica. L(Balaka). Phylanthus emlica is a type wild plant that grows open spaces in lowland tropical rain forests. Observing its life characteristic and its habitat, then Balaka plant (Phylanthus emlica) in Padang Lawas Temples’ yards was not planted in purpose planted but grows naturally. Balaka plant (Phylanthus emlica) has different name in every area. In Melayu, this plant is known as malaka. In Minangkabau known as balaka, in Sunda known as malaka and in Java, this plant is known as Kemloko, meanwhile in Madura and Bali this plant is called mlakah ,and karsinta in Flores (NTT)

scholarly journals Functional Trait Plasticity but Not Coordination Differs in Absorptive and Transport Fine Roots in Response to Soil Depth

Forests ◽  
2019 ◽  
Vol 11 (1) ◽  
pp. 42
Author(s):  
Yan Wang ◽  
Zhongyue Li ◽  
Zhengquan Wang ◽  
Jiacun Gu
Keyword(s):  
Fine Roots ◽  
Environmental Changes ◽  
Soil Depth ◽  
Specific Root Length ◽  
Root Traits ◽  
Functional Trait ◽  
Resource Exploitation ◽  
Soil Layers ◽  
Root Branching ◽  
Trait Plasticity

Absorptive and transport fine roots (diameter ≤ 2 mm) differ greatly in anatomy, morphology, and physiology, as well as their responses to environmental changes. However, it is still not well understood how their functional traits and biomass repartition respond to resource variability associated with increasing soil depth. Herein, we sampled the first five order roots of three hardwoods, i.e., Juglans mandshurica Maxim., Fraxinus mandshurica Rupr., and Phellodendron amurense Rupr. at surface (0–10 cm) and subsurface (20–30 cm) soil layers, respectively, and measured root biomass, anatomy, morphology, chemistry, and physiology at the branch-order level. Based on the anatomical characteristics, absorptive and transport fine roots were identified within each order, and their amounts and functional trait plasticity to soil depth were examined. The results showed that across soil layers, the first three order roots were mainly absorptive roots, while the fourth- and fifth-order roots were transport ones. From surface to subsurface soil layers, both the number and biomass proportion of absorptive fine roots decreased but those of transport fine roots increased. Transport fine root traits were more plastic to soil depth than absorptive ones, especially for the conduit-related traits. Absorptive fine roots in surface soil generally had stronger potential for resource acquisition than those in deeper soil, as indicated by their longer specific root length and greater root branching density. In comparison, transport fine roots in deeper soil were generally enhanced in their transportation function, with wider stele and higher hydraulic conductivity. Our findings suggest that functional specialization via multi-trait plasticity and coordination in both absorptive and transport fine roots along the soil depth would benefit the efficient soil resource exploitation of trees in forest ecosystems.

Population dynamics of canopy trees in New Caledonian rain forests: are monodominant Nothofagus (Nothofagaceae) forests successional to mixed rain forests?

2013 ◽  
Vol 29 (6) ◽  
pp. 485-499 ◽  
Author(s):  
Jennifer Read ◽  
Tanguy Jaffré
Keyword(s):  
New Caledonia ◽  
Single Species ◽  
Secondary Forests ◽  
Rain Forests ◽  
Term Change ◽  
Shade Tolerant Species ◽  
Successional Stages ◽  
Continuous Regeneration ◽  
Canopy Species

Abstract:In New Caledonia, rain forests with an upper canopy dominated by single species of Nothofagus occur next to mixed-canopy forests, without discernible environmental cause. A potential explanation is that they are different successional stages. To test this hypothesis and predict long-term change in canopy dominance, population size structures of 61 canopy species were analysed in six Nothofagus-dominated forests and three adjacent mixed rain forests. Weibull analysis suggests that these Nothofagus forests are secondary forests, with recruitment insufficient to maintain monodominance, except at a high-altitude site. At low- to mid-altitudes the Nothofagus canopy is predicted to develop into a mixed canopy, unless moderate to severe disturbance occurs within its reproductive lifespan. However, adjacent mixed rain forests are also secondary, with 85% of analysed species showing no evidence of continuous regeneration. Fifteen species from both forest types showed reverse-J curves suggesting continuous regeneration, but only Calophyllum caledonicum did so consistently. Since few canopy species showed evidence of high shade tolerance and persistence, a small number of shade-tolerant species is predicted to dominate both forests in the long term, in the hypothetical absence of disturbance. Hence, temporal factors associated with disturbances play a key role in determining dominance in these forests.

Sign in / Sign up

Export Citation Format

Share Document