Small mammals and habitat structure in lowland rain forest of Peninsular Malaysia

1985 ◽  
Vol 1 (1) ◽  
pp. 5-22 ◽  
Author(s):  
Catherine Kemper ◽  
David T. Bell
Keyword(s):  
Small Mammal ◽  
Rain Forest ◽  
Habitat Structure ◽  
Primary Forest ◽  
Small Scale ◽  
Simple Method ◽  
Habitat Differences ◽  
Faunal Distribution ◽  
Habitat Variables ◽  
Trapping Sites

ABSTRACTA method of assessing rain forest structure by ranking relative abundance of 41 habitat variables was used to describe habitat differences among six trapping sites (324 subsites). Variables included aspects of all vegetation layers but concentrated on those considered to be important to small mammal distribution. Ordination and classification methods resulted in similar analyses of the data. Differences in habitat structure were primarily related to the moisture conditions of the trapping sites and secondarily to their successional age (regenerating versus primary forest). The most important habitat variables for differentiating between sites were LITTER, CLEARING, SOILS, PIG DAMAGE, FLOODING, FAN PALM, EMERGENTS, CANOPY SURFACE and SEEDLINGS. Habitat structure also varied within sites with some suggestion of small-scale patterning.Small mammal captures were more likely in drier sites and subsites, but there was no difference in trap success between regenerating sites and primary forest sites. Greater numbers of species were captured in sites containing a variety of habitats, a discrete layering of vegetation and an extensive understorey. Small mammal captures were positively associated with five habitat variables (EMERGENTS, LITTER, ROTTING LOGS, SEEDLINGS, ROUGH BARK) and negatively associated with five others (LAYERS, BERTAM, SEDGES, PIG DAMAGE, FLOODING). The destruction caused by pigs is thought to be a major factor since it reduces litter and food availability over wide areas. Leopoldamys sabanus was the most abundant small mammal captured (40/68 individuals) and trap success differences among sites (0.4–1.9%) reflect its preference for higher, well-drained habitats.The study demonstrates the usefulness of a simple method of ranking habitat features according to importance/abundance thus eliminating the all but impossible task of direct measurements in this complex system. This simple method of habitat description provides a basis for studying variables influencing faunal distribution patterns.

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.

Kauri forests in the New Hebrides

1975 ◽  
Vol 272 (918) ◽  
pp. 369-383 ◽  
Keyword(s):  
Rain Forest ◽  
Tropical Rain Forest ◽  
Selective Logging ◽  
Primary Forest ◽  
Small Scale ◽  
Close Proximity ◽  
Preliminary Account ◽  
Lowland Tropical Rain Forest ◽  
New Hebrides ◽  
Basaltic Soils

A preliminary account is given of lowland tropical rain forest in which Agathis obtusa is dominant on basaltic soils. On the islands of Erromanga and Aneityum the shade tolerant Agathis seedlings often develop in close proximity to the parent trees, usually in small canopy gaps provided by the death or deterioration of Calophyllum and other associated broadleaved trees. There is no accumulation of litter or mor humus beneath Agathis obtusa and no evidence of podzolization was found. Agathis obtusa appears to be one of the most stable components of the lowland primary forest in the New Hebrides and no windthrown trees were found. It is suggested that the emergent Agathis could moderate the effect of hurricane-force winds on the broadleaved canopy but that the smaller canopy breaks allow the growth of previously established but stagnating Agathis seedlings; similar release of Agathis regeneration has resulted from small-scale selective logging on Aneityum.

Gas Cooling and Humidification: Design of Packed Towers from Small-Scale Tests

1950 ◽  
Vol 163 (1) ◽  
pp. 41-53 ◽  
Author(s):  
W. F. Carey ◽  
G. J. Williamson
Keyword(s):  
Operating Conditions ◽  
Total Heat ◽  
Small Scale ◽  
Water Cooling ◽  
Packed Tower ◽  
Simple Method ◽  
Worked Example ◽  
Gas Cooling ◽  
Heat Method ◽  
Working Out

On plants in which gases are processed, the gases are often brought into direct contact with water—usually in packed towers. The purpose may be to cool a hot gas, to increase the humidity of a gas, or, in the well-known special case of water-cooling towers, to cool water by contact with atmospheric air. These processes involve simultaneous transfers of sensible heat and water vapour, and existing methods of analysis are complex and laborious, except for the cooling of water, for which Merkel's total-heat method has long been available. Merkel's approximate solution offers the engineer a simple method of working out, for any operating conditions, the amount of heat transferred and the “driving force” available for transferring it. The present paper generalizes the total-heat method and, with a permissible sacrifice in accuracy, preserves the essential simplicity of the water-cooling treatment for gas-cooling and humidification processes. To complete the design of a packed tower, a knowledge is required of the characteristics of the packing. Information obtained in small towers is given for a number of packings, and a worked example shows how to apply the method of treatment, and the packing data presented, to the design of a large plant tower.

Identification of the best topology of delta configured three phase induction generator for distributed generation through experimental investigations

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Vanka Bala Murali Krishna ◽  
Sandeep Vuddanti
Keyword(s):  
Distributed Generation ◽  
Reactive Power ◽  
Voltage Regulation ◽  
Reactive Power Compensation ◽  
Induction Generator ◽  
Experimental Investigations ◽  
Small Scale ◽  
Empirical Formulas ◽  
Simple Method ◽  
Main Challenge

Abstract Research on Self –excited induction generator (SEIG) brings a lot of attentions in the last three decades as a promising solution in distributed generation systems with low cost investment. There are two important fixations to attend in the operation of SEIG based systems, a) excitation and b) voltage regulation. Many procedures are reported regarding selection of excitation capacitance in the literature, based on state-state analysis, dynamic modeling, empirical formulas and machine parameters which involve various levels of complexity in findings. Moreover, the voltage regulation is the main challenge in implementation of SEIG based isolated systems. To address this problem, many power electronic-based schemes are proposed in the literature and but these solutions have few demerits importantly that additional cost of equipment and troubles due to failure of protection schemes. In particular, the installation of SEIG takes place at small scale in kW range in remote/rural communities which should not face such shortcomings. Further in case of off-grid systems, the maximum loading is fixed based on connected rating of the generator. This paper presents the various methods to find excitation capacitance and illustrates an experimental investigation on different possible reactive power compensation methods of delta connected SEIG and aimed to identify a simple method for terminal voltage control without power electronics. In this experimental work, the prime-mover of the generator is a constant speed turbine, which is the emulation of a micro/pico hydro turbine. From the results, it is found that a simple delta connected excitation and delta configured reactive power compensation limits voltage regulation within ±6% while maintaining the frequency of ±1%, which make feasible of the operation successfully in remote electrification systems.

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 Habitat, food, and small mammal community structure in Namaqualand

Koedoe ◽  
2006 ◽  
Vol 49 (1) ◽  
Author(s):  
M. Van Deventer ◽  
J.A.J. Nel
Keyword(s):  
Species Richness ◽  
Food Availability ◽  
Small Mammal ◽  
Plant Cover ◽  
Plant Litter ◽  
Shrub Cover ◽  
Habitat Features ◽  
Habitat Differences ◽  
Elephant Shrew ◽  
Density And Biomass

The effect of habitat differences and food availability on small mammal (rodent and elephant shrew) species richness, diversity, density and biomass was investigated in Namaqualand, South Africa. Species richness in the three habitats sampled, namely Upland Succulent Karoo, Dry Riverine Shrub and North-western Mountain Renosterveld was low, with only 2–4 species per habitat. Rodents trapped were predominantly Gerbillurus paeba and Aethomys namaquensis, with fewer Mus minutoides and Petromyscus sp. The only non-rodent was the elephant shrew Elephantulus edwardii. Ten habitat features, the percentage of total plant cover, tree cover, shrub cover, grass cover, plant litter, total basal cover, sand, gravel or rock cover, and the dominant plant height were recorded at 30 randomly chosen points on five sampling grids in each habitat. Small mammal density and biomass was significantly correlated with food availability (green foliage cover, seeds, and relative density and biomass of insects). Species richness and diversity of small mammals were significantly correlated with shrub cover. Numbers and biomass of specific species correlated significantly with different habitat features in each case.

Fruit biomass and relative abundance of frugivores in a rain forest of southern Western Ghats, India

1999 ◽  
Vol 15 (4) ◽  
pp. 399-413 ◽  
Author(s):  
T. Ganesh ◽  
Priya Davidar
Keyword(s):  
Rain Forest ◽  
Western Ghats ◽  
Primary Forest ◽  
Mountain Forests ◽  
Edaphic Factors ◽  
Lowland Forest ◽  
Fleshy Fruits ◽  
Sclerophyll Forest ◽  
Southern Western Ghats ◽  
Avian Frugivores

Fruit biomass and frugivore abundance were quantified over 3 y in a rain forest of the south Western Ghats, India. Fruit biomass was estimated by sampling fruit fall in the primary forest, and frugivore abundance by a 2.5-km transect. A total of 645 kg ha−1 of fruit was produced annually in the forest. Only 49% of this is edible to the frugivores and the remaining 51% is in the form of non-edible husks. Mammalian frugivores outnumbered avian frugivores and the majority of the mammals were seed predators. The total fruit biomass produced at Kakachi is lower than in the lowland forest and mountain forests in the neotropics but higher than in the wet sclerophyll forest of Australia. Lower diversity of trees and edaphic factors at Kakachi could be some of the reasons for these differences. On the other hand, paucity of fleshy fruits, low density of trees producing fleshy fruits and irregular fruiting of these species, account for the low number of obligate avian frugivores at Kakachi.

Effects of a Transmission Line on Bird Populations in the Red Lake Peatland, Northern Minnesota

The Auk ◽  
1984 ◽  
Vol 101 (3) ◽  
pp. 487-498 ◽  
Author(s):  
Gerald J. Niemi ◽  
JoAnn M. Hanowski
Keyword(s):  
Transmission Line ◽  
Habitat Structure ◽  
Breeding Population ◽  
Habitat Characteristics ◽  
Population Densities ◽  
Yearly Variation ◽  
Bird Populations ◽  
Census Methods ◽  
Habitat Differences ◽  
Transect Counts

Abstract The effects of a 500-kV transmission line on bird populations were assessed by comparing paired treatment areas [which included a transmission line and right-of-way (ROW)] with similar control areas in six different habitat types during the breeding and migration seasons. Habitat structure was measured to examine the inherent differences between control and treatment areas. Using two census methods, territorial mapping and transect counts, we determined that Sedge Wrens and LeConte's Sparrows had lower breeding-population densities in treatment areas than in control areas. LeConte's Sparrows and Connecticut Warblers occurred at greater mean distances from the transmission line in treatment areas than from a similarly positioned line in control areas. Fifteen paired t-tests (five habitats in 3 yr), in which territorial mapping data were used, revealed that community densities were lower in one treatment habitat (high shrub) in 1 of 3 yr (P < 0.05). A two-way analysis of variance with transect counts, however, was not confirmatory when yearly variation was included. Transect counts revealed lower population densities in one treatment habitat (low shrub) in 2 of 3 yr (P < 0.05). In contrast, we observed greater species richness (P < 0.05) in two treatment habitats (closed spruce and sedge fen) than in controls. Treatment habitats were most similar in habitat structure to their paired control habitats, but each habitat of the pair was significantly different (P < 0.05) from the other in at least 2 of 10 habitat characteristics analyzed. We suggest that the avian differences observed between paired areas were primarily attributable to (1) the inherent habitat differences between control and treatment areas, and (2) the new habitat created under the transmission line. Our data indicated negligible effects of this transmission line on bird populations, but interpretations are difficult, because the effects varied with (1) habitat, (2) season, and (3) method considered. Postimpact studies, which compare control and treatment areas, are less effective than before-and-after studies, because differences in habitat structure exist between any two areas.

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