Population dynamics of two sympatric isopod species in a pine forest in central Java, Indonesia

Abstract

The populations of two dominant isopod species in a Pinus merkusii forest on the southern slope of mount Ungaran in central Java, Indonesia, were periodically sampled during one year using Tullgren extractions from soil cores. The aim of the research was to collect more information about the life-cycles of tropical isopods by analysing size-class distributions of two sympatric isopod species, belonging to the genus Burmoniscus. Biomass of the populations was estimated from length-weight conversions established for each species in the laboratory. The efficiency of the Tullgren extraction method was estimated by comparison to hand sorting; no difference was found between these methods.The abundance of the two species differed significantly with time. Burmoniscus Sp. A was more abundant during the wet season, whereas the population fluctuations of Burmoniscus Sp. B were more spread over the year. Reproduction of both species took place in the wet season. Burmoniscus Sp. A had one generation per year, while for Burmoniscus Sp. B the situation was unclear due to extensive overlap of size classes. Comparisons were made with isopod abundance in other tropical and temperate forests. The mean density of the two species found in this study was 258 m-2 for Burmoniscus Sp. A and 272 m-2 for Burmoniscus Sp. B, while biomass was 80.4 mg m-2 and 37.6 mg m-2, respectively. The data suggest that densities of isopods in tropical pine forests may be considerably higher than in comparable temperate ecosystems.

Stratification and seasonal stability of diverse bacterial communities in a Pinus merkusii (pine) forest soil in central Java, Indonesia

“…The soil type has been classified as brown andosol. A more detailed description can be found elsewhere (Vink and Purwanti, 1994; Krave et al. , 2002).…”

Diversity and population characteristics of terrestrial isopods (Crustacea, Oniscidea) across three forest environments in southern Brazil

“…Pinus leaf litter has many components impalatable to edaphic animals (vink & purWanti, 1994), which raises the need for increasing litter palatability and digestibility by weakening its physical and chemical structure through microorganismal actions (haSSall & ruShton, 1984). In the Pinus case, fungi can be ingested along with litter (Soma & Saitô, 1983;haSSall & ruShton, 1984).…”

Soil macroinvertebrates as indicators of pollution by heavy metals

“…Some of them can survive high levels of metal in their food by modifying metal uptake and excretory rates [24]. Response of Diplopoda to metal pollution differs among species, as some species can be more abundant in polluted areas than in unpolluted sites [17,25]. Nevertheless, a recent study in comparable sites [6] showed the absence of correlation between Diplopoda density and soil metal content.…”