The movement and habitat utilization patterns were studied in an Asian elephant population during 1981–83 within a 1130 km2 area in southern India (11° 30′ N to 12° 0′ N and 76° 50′ E to 77° 15′ E). The study area encompasses a diversity of vegetation types from dry thorn forest (250–400 m) through deciduous forest (400–1400 m) to stunted evergreen shola forest and grassland (1400–1800 m).

Home range sizes of some identified elephants were between 105 and 320 km2. Based on the dry season distribution, five different elephant clans, each consisting of between 50 and 200 individuals and having overlapping home ranges, could be defined within the study area. Seasonal habitat preferences were related to the availability of water and the palatability of food plants. During the dry months (January-April) elephants congregated at high densities of up to five individuals km-2 in river valleys where browse plants had a much higher protein content than the coarse tall grasses on hill slopes. With the onset of rains of the first wet season (May-August) they dispersed over a wider area at lower densities, largely into the tall grass forests, to feed on the fresh grasses, which then had a high protein value. During the second wet season (September-December), when the tall grasses became fibrous, they moved into lower elevation short grass open forests.

The normal movement pattern could be upset during years of adverse environmental conditions. However, the movement pattern of elephants in this region has not basically changed for over a century, as inferred from descriptions recorded during the nineteenth century.

Much of the unique native vegetation of Mauritius has been destroyed. Coastal ebony (Diospyros egrettarum I.B.K. Richardson) forest forms an extreme type of Mauritian lowland forest which no longer exists on mainland Mauritius and only survives on one offshore islet, Ile aux Aigrettes. Undisturbed D. egrettarum forest is resistant to invasion by exotic plants, which have now invaded most relict patches of native lowland vegetation in Mauritius. Human disturbance however, has allowed many exotics (particularly Flacourtia indica (Burm. fil.) Merrill) to invade and form new vegetation types. Much of the disturbance was caused by illegal woodcutting up to 1985, prompted by an acute fuelwood shortage in Mauritius. On the basis of 132 4 X 4 m quadrats, we recognize 10 types of natural, semi-natural and exotic vegeta-tion. The conservation of the remaining natural ebony woodland vegetation requires the total cessation of woodcutting and the eradication of Tabebuia pallida (Lindl.) Miers (potentially the most damaging exotic species).

A floristic and ecological study of epiphytic bryophytes and lichens on standing mature Eperua trees was carried out in dry evergreen (walaba) forest in Guyana, South America. The trees were sampled from their base up to the highest canopy twigs, using mountaineering techniques. Clear vertical distribution patterns of epiphytic species and life-forms were found. Many species, particularly foliose lichens, appear to be preferential or exclusive to either Eperua grandiflora or E. falcata (Leguminosae), which are the dominant trees in the walaba forest. Special attention is given to the species-rich epiphyte vegetation on the upper canopy twigs, which include two categories of species: the sun epiphytes and the pioneers (facultative epiphylls).

Trapping and netting of small mammals on a land-bridge island (Leyte) and on an oceanic island (Negros) revealed similar patterns of elevational change in abundance and species richness. Fruit bats (Pteropodidae) reached their greatest local densities in agricultural areas, and were least abundant in montane mossy forest. The fruit bats found to be common in agri-cultural areas are widespread in Southeast Asia: in contrast, species that were most common in forested areas are Philippine endemics. Fruit bat abundance was greater on the oceanic island than on the land-bridge island. Trappable small mammals (families Soricidae and Muridae) showed no change in species richness with increasing elevation, but did show a gradual increase in overall abundance. Even though the oceanic island was depauperate of non-volant mammal species, it had the higher abundance of non-volant mammal individuals; however, this may have been due primarily to differences associated with the elevation of sampling sites. Murid rodents at the higher elevations on Leyte tend to be those that are members of the old endemic group of Philippine murids, and those at lower elevations tend to be members of more recently arrived groups. Most non-volant small mammals at all elevations on the oceanic Negros, and in agri-cultural areas on Leyte, are non-native species.

Flowers of Aphelandra sinclairiana have features of flowers pollinated by hermit humming-birds (long corollas) and of those pollinated by territorial humming-birds (dilute nectar, clustered distribution). Flowers in large clumps at the peak of the blooming season were pollinated by two territorial humming-birds, but at the end of the season or in isolated plants the main avian pollinator was the non-territorial hermit Phaethornis superciliosus. Visits by avian nectar thieves were more frequent at high flower densities. The reproductive output of inflorescences was similar at different levels of flower aggregation. Aphelandra flowers in large clumps could exchange pollen with extraterritorial plants because territorial humming-birds did not completely exclude pollinating hermits. The commonest nectar thief at high flower aggregations was the passerine Vermivora peregrina, the second most common nectar thief was the hermit Phaethornis longuemareus.

The density of arboreal arthropods in a dry evergreen forest in Northeastern Thailand was investigated by the insecticide fogging (knockdown) method. Arthropod densities of 256.4 and 140.4 m-2 were recorded in the dry season and 195.2 and 123.1 m-2 in the rainy season. The main orders were Collembola, Thysanoptera, Hymenoptera (mainly Formicidae) and Hemiptera. Distinct differences were not found in the arthropod faunal structure and density between the dry and rainy seasons. However, this fauna is completely eliminated by the clearing and burning of forest for shifting cultivation.

The results of an experiment investigating the rate of arthropod fall after application of insecticide are presented and problems concerning the efficiency of the estimation methods used in this study are discussed.

The breeding season and diet of the rat Arvicanthis was monitored from December 1983 to November 1985 in the semi-arid Sudan savanna at Kano, Nigeria, West Africa. Breeding began 1–2 months before the start of the rainy season and ceased at the beginning of the dry season. The diet of Arvicanthis was omnivorous, but with seasonal differences. Monocotyledons and dicotyledons predominated in the diet in the dry season, with seeds and insects increasing in the diet in the rainy season. The major differences between the ecology of Arvicanthis at Kano and on the East African savanna were that in East Africa the breeding season is longer and begins after the start of the rainy season. These and other dissimilarities between the biology of Arvicanthis in the two areas could be due to the effect of climatic differences on food supply and to the possible existence of different taxonomic groupings of Arvicanthis in the two regions.

Foraging and attendance of birds at army-ant swarm raids were studied in the tropical rain forest of Los Tuxtlas, Mexico. Sixty-eight raiding swarms were intercepted over a four-year period of which 57% were Eciton burchelli and 43% Labidus praedator. A total of 461 birds (37 species/12 families) were recorded at swarms of E. burchelli and 208 birds (34 species/10 families) were recorded at L. praedator swarms. The mean number of bird species detected per swarm was 7.2 at E. burchelli raids and 5.6 at L. praedator raids. Red-throated ant-tanagers (Habia fuscicauda) were most frequently seen at the swarms of both army-ant species. Other important species were the golden-crowned warbler (Basileuterus culicivorus), the white-breasted wood wren (Henicorhina leucosticta) and the Kentucky warbler (Oporornis formosus). Swarms of both army-ant species were active year-round. Birds weighing between 20 and 40 g dominated perches closest to the ground and the central zone of the swarms, richest in animal prey. Birds weighing less than 20 g occupied higher perches and tended to forage in more peripheral zones. At Los Tuxtlas raiding swarms of army ants are important in the foraging ecology of 44 bird species, including 12 North American migrants.

Many woody species in humid tropical forests synchronously flush entire canopies of young red leaves. Numerous unsuccessful attempts have been made to explain the adaptive value of this visually striking phenomenon. In the humid tropics, fungal attack is a potentially important source of mortality for expanding young leaves. We propose that the anthocyanins responsible for the red coloration of young leaves may play a protective role against invasions by leaf-attacking fungal pathogens.

Fungus-growing leaf cutting ants (Atta columbica Guerin) were used in choice tests because they are known to select against leaves or chemicals containing fungicidal properties. In feeding trials with leaf discs from 20 common species, ant preference decreased significantly with increasing anthocyanin content. In feeding trials with pure anthocyanin (3,3',4',5,7-pentahydroxyflavylium chloride) presented on oat flakes, ants again showed a significant dosage dependent preference. This suggests that even low concentrations of anthocyanins may be harmful to the fungal colonies of ants. Additional work on the effects of anthocyanin on leafattacking fungi is encouraged.

Litterfall in primary and secondary forests (‘capoeira’) in eastern Brazilian Amazonia was measured fortnightly from August 1979 to October 1980. The nutrient contents of the litter (N, P, K, Ca and Mg) were determined.

Litterfall differed between the two forest types (primary forest − 8.04 t ha−1 yr−1; secondary forest − 5.04 t ha−1 yr−1). The value obtained for primary forest was similar to those reported elsewhere in Brazil (mean = 8 t ha−1 yr−1) and from other regions of S. America (mean = 7.20 t ha−1 yr−1).

Prediction of net primary production from litterfall at the primary forest site gave rise to values of 14.47 and 26.53 t ha−1 yr−1. Estimates of net primary production in ‘capoeira’ ranged from 9.07 to 16.63 t ha−1 yr−1.

Seasonality of litterfall was more marked in ‘capoeira’ than primary forest but in both cases was less pronounced than elsewhere in Brazil.

Nutrient concentrations were highest in ‘capoeira’ litter, a finding which accords with results from other tropical sites; nevertheless input of nutrients per unit area of forest floor was greatest in the primary forest.

This study was conducted in a woodland savanna in western Venezuela exclosed from grazing and burnt once a year towards the end of the dry season. Mean annual rainfall is 1500 mm, with a strong seasonality.

Two cohorts of seedlings of Andropogon semiberbis were tagged and monitored for up to three years. Several variables such as survivorship, plant size, seedling density, fire damage and distance to the nearest adult were measured or estimated. Two burning experiments to measure survivorship before and after fire, and two seedling-growth experiments to assess competitive interference from adult plants of three grass species were performed.

The highest mortality takes place during the dry season and is due to fire. This decreases as the plants get bigger due to increasing structural complexity of the clump by growth which gives added protection to the meristems. Other mortality factors such as desiccation, uprooting and shading seem to be important during the wet season, when mortality rate is relatively constant. Survivorship during the first year and after three years is strongly correlated to the size attained by the end of the first growing season.

Seedling densities are rather low and do not seem to play any role in survivorship in this population. Adult interference with seedling growth decreases with distance and seems to be due to root competition, although there is a tendency toward increased foliage interference related to the canopy structure of adult plants.

Throughout the latter part of the dry season (January-April) of 1985 and 1986, we studied the demography of mature adults in a small population of Argia chelata along a stream at Monteverde, Costa Rica. Males defended sunlit spots along the stream between 1030 h and 1400 h central standard time each day and females visiting these sunlit spots were soon mated. By individually marking all mature adults in the population we found that there was no significant difference between the sexes in daily survival rates (0.85 for males and 0.86 for females). Lifetime mating success was positively correlated with longevitiy in both males and females but the ability of males to obtain a mate appeared to be independent of age.

Although the sex ratio at emergence was 1:1, that of mature adults at the stream was strongly male-biased (87% male), perhaps as a result of a longer or more risky prereproductive period in females related to the costs of egg formation. We argue that the strongly male-biased sex ratio has important effects on the mating system of this species in that the male contact-guards the female for the entire oviposition period each day. Although this limits each male to mating with one female per day, it probably ensures that the male will fertilize most of the eggs laid by the female that day.

A standard Rothamsted light trap was operated for slightly over 12 months from the end of September 1979 to October 1980 at Genting Sempah, Pahang in Malaysia. All specimens of macrolepidoptera families together with the Pyralidae were identified, counted and recorded. The numbers of species caught were compared with those obtained by a different method at a nearby site for over 10 years. Diversity, biomass and seasonality of the catch were compared with identically sampled populations in Great Britain and New Zealand. The Genting Sempah trap had very high diversity and biomass compared with the temperate samples and exhibited much less seasonality. The Pyralidae and other families (excluding Noctuidae and Geometridae) formed a much higher component of diversity in Genting than in Britain. The log-normal distribution fits the data better than the log-series. So the inter-quartile slope, Q, is the correct parameter for interfaunal comparisons.

Sixty bird species ate the figs of 29 Ficus taxa at a lowland forest site in Peninsular Malaysia. Although most bird-eaten figs were brightly coloured, four Ficus species produced dull-coloured ripe fruits. Whilst there was tremendous overlap in the sizes of figs eaten by different bird species, data presented show that the fig resource was partitioned by birds. Large birds were commoner visitors to large-fruited Ficus, but small birds tended to eat small figs. Within two avian genera, the Treron pigeons and Megalaima barbets, there was distinct partitioning of figs consumed according to fig size.

Cerrado is a species-rich savanna-like vegetation that covers a large area in central Brazil. Soil, and particularly soil fertility, is considered to be the major factor determining the wide and diverse physiognomic-floristic gradients encountered within cerrado vegetation. To describe the vegetational variations within a cerrado in southern Mato Grosso state (15° 21'S, 55° 49'W), a 1 ha transect was located to pass through an interfluvial cerrado and climb a steep talus slope. The vegetational and environmental variations are described by means of field classification, direct gradient analysis and reciprocal averaging ordination. The effects of differences in ground water regime in the interfluvial cerrado and differences in inclination with associated rockiness in the talus cerrado are related to the vegetational variations. As the soils are very similar in texture and in the majority of chemical properties, the role of the above environmental factors was more easily distinguished. In the interfluvial cerrado, the vegetation variations are probably related to the seasonal fluctuation in water table level.

Patterns of edge-related environmental changes and plant water relations were investigated in the isolated forest reserves of the INPA-WWF Minimum Critical Size of Eco-systems project near Manaus, Brazil early in the wet season.

Air temperature was elevated and humidity reduced in the understorey within 40 m of the reserve margins, and air temperature and vapour pressure deficit (VPD) were higher in the interiors of 1 ha reserves than in 100 ha reserves. There was increased photosynthetically active radiation penetration to understorey level up to 40 m into a 100 ha reserve.

Soil moisture was depleted in the outer 20 m of both small and large reserves, and surface soil water potentials fell below – 1.5 MPa at the margin of a 1 ha reserve.

Studies of leaf relative water contents (RWCs) in understorey shrubs revealed no appreciable saturation deficits, though RWCs were sometimes lower at the reserve margins. Studies of leaf conductances revealed no evidence of restriction of water loss in these plants, and conductances of plants near the edges were significantly higher and higher for longer.

The implications of these results for reserve design and for local and regional water budgets, as well as the possible role of water stress in increased tree mortality in isolated reserves are discussed.

Padrōes de mudanças ambientais e hídricos de plantas relacionados a bordas de matas isoladas foram investigadas no início da estação seca nas reservas de floresta do Projeto Dinâmica Biológica de Fragmentos Florestais do INPA-WWF, proximo de Manaus, Brasil.

No sub-bosque, até 40 m da borda da mata, a temperatura ambiental estava elevada e a umidade reduzida, e a temperatura do ar e o DPV estavam maiores nas reservas de 1 ha do que nas reservas de 100 ha. A penetração de radiaçao fotosintéticamente ativa no sub-bosque estava aumentada até 40 m da borda em reservas de 100 ha.

A umidade do solo baixou consideravelmente nos 20 m periféricos de reservas grandes a pequenas, e o potencial hídrico na superficie do solo baixou para menos de −1.5 MPa na margem de uma reserva de 1 ha.

Estudos do teor relativo de água (TRA) em folhas de arbustos de sub-bosque nӑo revelaram deficits de saturação apreciaveis apesar de que TRAs foram menores nas bordas das reservas. Estudos da conductancia foliar não revelaram evidência de restrições de perdas hídricas nessas plantas, e as conductancias de plantas próximas a bordas foram significativamente maiores durante um período mais longo.

As impliçõtes desses resultados para o planejamento de reservas e para o balanço hídrico local e regional, assim como as possiveis funçoes de ‘stress’ hídrico na alta mortalidade de árvores em reservas isoladas são discutidas.

A total of 392 small mammals belonging to five species of small rodents and four species of shrews were caught. The small mammals and their percentage composition were Crocidura nigeriae (20.9%), Crocidura grandiceps (11.7%), Crocidura crossei (9.7%), Crocidura flavescens manni (20.4%), Mus musculoides (39.0%), Praomys tullbergi (11.5%), Lophuromys sikapusi (3.6%), Lemniscomys striatus (1.3%), and Arvicanthis niloticus (0.3%).

There were monthly variations in the number of Mus musculoides and Crocidura nigeriae.

In Mus musculoides breeding was at a maximum at the beginning and towards the end of the wet season and early dry season. In Crocidura nigeriae breeding was maximal during the wet season and low in the dry season.

The seasonal changes in the age structure of the two most common species: Mus musculoides and Crocidura nigeriae, are described.

Both vertebrate- and wind-dispersed seeds moved farther from rain forest into old field than from old field into forest. Vertebrate-dispersed seeds from the rain forest moved farther into the field than wind-dispersed seeds, but seeds of both types moved similar distances from field into forest.

Habitat structure affected seed deposition patterns in the field, where shrubs provided perches for flying vertebrates. Vertebrate-dispersed seed deposition was significantly greater, and deposition of plumed, wind-dispersed seeds was significantly less, under shrubs than in the open. Deposition of vertebrate-dispersed seeds under fruiting shrubs was significantly less than under non-fruiting shrubs.