Submontane Rainforest Research Articles

Stem Cracks and Decay in Newtonia buchananii Trees in the Mazumbai Forest Reserve, West Usambara Mountains, Tanzania

Stem cracks, decay and bark pattern in Newtonia buchananii trees were investigated and compared in a submontane rain forest in the Mazumbai Forest Reserve and adjacent human disturbed forest. One third of the trees growing in the reserve (32 %) and more than half of those in the disturbed forest (60 %) had stem cracks and/or decay—mainly as butt rot, often accompanied by brackets of wood-rotting fungi. One fifth (20 %) of the trees growing in the reserve and three quarters (76 %) in the disturbed forest showed rough and rugose bark. As N. buchananii is a main climax species in the area, the outcome of the death of the trees will be the formation of big gaps. Gap formation in the reserve seems to be accelerating and going beyond the ‘normal’ levels of a natural rain forest ecosystem, whereas in the disturbed areas it seems that N. buchananii will be extinct in the future.

NEW SPECIES OR INTERESTING RECORDS OF FOLIICOLOUS LICHENS. II. FLAVOBATHELIUM EPIPHYLLUM(LICHENIZED ASCOMYCETES: MELANOMMATALES)

Flavobathelium epiphyllumgen. et sp. nov. is described and illustrated. The new taxon is characterized by perithecia and pycnidia embedded in pulverulaceous, uni- to plurilocular pseudostromata, small, transversely septate ascospores, and the presence of bacillar to filiform macroconidia with gelatinous appendages and simple microconidia. Possible relationships are seen with the genus Phyllo-bathelium. Flavobathelium epiphyllumis a common species in Central and South American lowland to submontane rain forests with undisturbed vegetation. It is mostly found along moderately illuminated parts of the understory, such as small, natural light gaps.

New Species or Interesting Records Of Foliicolous Lichens. II. Flavobathelium Epiphyllum (Lichenized Ascomycetes: Melanommatales)

Flavobathelium epiphyllum gen. et sp. nov. is described and illustrated. The new taxon is characterized by perithecia and pyenidia embedded in pulverulaceous, uni- to plurilocular pseudostromata, small, transversely septate ascospores, and the presence of bacillar to filiform macroconidia with gelatinous appendages and simple microconidia. Possible relationships are seen with the genus Phyllobathclium. Flavobathelium epiphyllum is a common species in Central and South American lowland to submontane rain forests with undisturbed vegetation. It is mostly found along moderately illuminated parts of the understory, such as small, natural light gaps.

Diel activity of arboreal arthropods associated with Papua New Guinean trees

The diel activity of arboreal arthropods foraging within the crowns of nine species of trees native to submontane rain forests in Papua New Guinea was studied. Data were collected over a 30-day period, using modified flight-interception traps, which are described briefly. Sampling was designed to enable segregation of material into day- and night-catches. Arthropod activity (measured by the number of individuals collected) was correlated positively with minimum air temperature. As a probable consequence, overall arthropod activity was significantly higher during day-time than night-time and night catches represented 72% of day catches. Predators, parasitoids, wood-eaters, ant workers and entomophagous arthropods were significantly more active during day than night. Few arthropod groups showed an inverse behaviour. Regression slopes comparing entomophages versus herbivores during day- and night-time were not significantly different. The data do not support the hypothesis that herbivores are particularly ac...

Foliar Uptake of Water by Wet Leaves of Sloanea woollsii, an Australian Subtropical Rainforest Tree

At leaf water potentials (ψ) of around -2.5 MPa, detached leaves of Sloanea woollsii F.Muell., an Australian subtropical rainforest tree, were able to absorb small amounts of water vapour from a saturated atmosphere, but absorbed considerably more liquid water if their surfaces remained wet. When leaves attached to small branches exhibiting a ψ of -2 MPa were sprayed with water and maintained in a saturated atmosphere, leaf ψ returned to saturation values within about 6 h. In a further experiment, a ψ of -2 MPa was imposed on detached, forked branches. Branches were then exposed to a saturated atmosphere and leaves on one half of the fork were kept wet whilst the rest remained dry. Leaf ψ was measured periodically for both dry and wet leaves and in both cases was found to increase with time. This indicated that leaf surface water was imbibed by wet leaves and transported into the branch resulting in alleviation of low water potentials in the dry leaves. In the submontane rainforests in which S. woollsii occurs, extended periods with little or no rainfall occur regularly. Throughout the year, foliage is wet by fog or dew alone for about 25% of the time. It is suggested that the presence of leaf surface water during rainless periods when leaf Psi is low may be important for the survival of S. woollsii. The actual mechanism of foliar absorption is uncertain, but is likely to be direct imbibition through the cuticle.

A New Species of Ormocarpum (Leguminosae: Papilionoideae) from the Moist Forest of Eastern Tanzania

There are about 25 species in the genus Ormocarpum, with 17 species mostly confined to Africa (Lock, 1989), of which one, 0. sennoides (Willd.) DC., has an Asian subspecies (subsp. sennoides). A number of the African species have fairly restricted distributions. For example, in the Flora of Tropical East Africa area (Gillett, 1971) there are 8 taxa recorded, of which two are confined to the coastal belt (0. sennoides subsp. zanzibaricum Brenan & J. B. Gillett and 0. schliebenii Harms), two are restricted to the north Kenya-Ethiopia-Somalia arid area (0. muricatum Chiov. and 0. keniense J. B. Gillett), and one is found only in the dry Ruaha valley of Tanzania in the Udzungwa mountain rainshadow (0. flavum J. B. Gillett). The remaining three are fairly widespread in woodland and bushland (0. trichocarpum (Taub.) Engl., 0. trachycarpum (Taub.) Harms and 0. kirkii S. Moore). In the course of conducting a floristic and ecological survey of the Mwanihana Forest Reserve in the northern Udzungwa mountains, Tanzania, a further species of Ormocarpum was discovered. The new species is distinctive both in its ecology, as it is the only eastern African species in submontane rainforest, and in its affinities, which are Guineo-Congolian. The new species is described here, and its phytogeographical affinities discussed.

Population biology and estimates of abundance of fruit bats (Pteropodidae) in Philippine submontane rainforest

Thirteen species of megachiropteran bats were captured in primary forest at 830–1000 m on Negros Island in the central Phillippines; 1229 individuals were marked and released. Individuals of six species were recaptured, for an overall recapture rate of 13%. For these six species, mean movement distance ranged from 0.16 to 0.75 km. For the two species with larger sample sizes, Haplonycteris fischeri Lawrence and Ptenochirusjagori Peters, adult males moved only one‐half as far as females or subadult males. For three species, Cynopterus brachyotis Muller, H. fischeri and P. jagori, minimum longevities in the wild of four or five years were documented. For the same species, estimates of combined subadult and adult annual survival were 60 to 80%. Density estimates for six species ranged from 0.2 to 3.7 individuals per hectare, with a cumulative density of about 10 bats per hectare. Considerable differences in proportional abundance were found between different subsamples of netted bats, but most of this variation could be accounted for by variation between habitats. Four species (Cynopterus brachyotis, Eonycleris spelaea Dobson, Macroglossus minimus Geoffroy, and Rousettus amplexicaudatus Geoffroy) that were common in agricultural habitats distant from forest were strongly associated with clearings and rare in forest; three species (Harpyionycteris whiteheadi Thomas, Nyctimene rabori Heaney and Peterson, and Ptenochirus jagori) that were as common in clearings as in forest, or slightly more common in clearings, are absent from sites more than a kilometre from forest or forest patches, and appear to use clearings principally as flyways; and one species (Haplonycterisfischeri) that was much more common in forest than in the adjacent clearings is elsewhere present only in or very near forest or in forest patches. Estimates of density of small subcanopy fruit bats that are derived from recapture data were found to be correlated with rank‐order abundance in moderate (c. 100 fruit bats) net‐samples in forest, and directly proportional to abundance of fruit bats in large (c. 300–500) samples in forest. This indicates that large netting samples can provide meaningful estimates of relative abundance for these species.

Late Cenozoic pollen spectra from the Atherton Tableland, north-eastern Australia

Pollen analysis of samples from a short sediment sequence on the Atherton Tableland, of Late Tertiary or Early Pleistocene age, provides the first evidence of existing vegetation within the region prior to about 100,000 years B.P. Comparison of fossil samples with modern pollen spectra suggests the presence of a submontane rainforest existing under a temperature regime some 3°C cooler than present. A number of ancient taxa including Nothofagus and several conifers, present in the fossil samples, no longer exists within the region. An attempt is made to explain their decline within an area that harbours a great diversity of rainforest species including many primitive angiosperms. Unfavourable climatic conditions combined with aspects of the dispersal ecology of the taxa would have been important contributing factors.