The types and causes of death of canopy and subcanopy trees were characterized for the tropical montane cloud forest of Tamaulipas, Mexico. Field work was carried out at the Biosphere Reserve ‘El Cielo’, located on the eastern slope of the Sierra Madre Oriental. Three study plots, each of 2 ha, were selected within the forest differing in their degree of exposure to wind. Results indicate that the tropical montane cloud forest presents a differential treefall regime derived from the great hurricane activity to which this mountain range is exposed. This effect is illustrated by the great number of fallen logs (545 trees in 6 ha) and the high percentage of uprooted (48.3%) and snapped off (37.6%) trees. Other treefall factors included the rocky and shallow soils and weakness of the dominant trees from insect attack. A differential disturbance level was obtained between zones. The disturbance was higher for the exposed zone, where the crown cover of emergent trees was not closed. Species composition of the dead material was related to the abundance of the overstorey species as standing vegetation. Ten of the 20 recorded species were able to sprout and just 7.5% of the 545 fallen trees were sprouting. Quercus germana, Q. sartorii, Clethra pringlei, Liquidambar styraciflua and Ceris canadensis, accounted for 78.5% of the gap-forming species. The type of treefall differed between species of the same genera: Q. germana was generally found uprooted, while Q. sartorii died standing probably because of previous weakening from dipterous insects.

Borassus aethiopum is a dioecious palm tree of African savannas. A stage-classified matrix population model has been parametrized with field data (Lamto reserve, Ivory Coast). It enabled the study of the persistence of the population, and analysis of its sensitivity to different vital rates. Age of palms in each stage were estimated to complete the description of the palm life-history. The main results are: (1) The studied populations are very close to the equilibrium but the stable stage distribution (predicted by the model) and the observed distribution are significantly different indicating a former change in the vital rates. (2) Reproduction seems to be highly delayed (first reproduction on average at 114 y), while the estimated duration of the reproductive part of the life-cycle is relatively short (22 y).

This study addresses the pollination ecology of shrub species in an upper montane forest in Costa Rica, where the diversity of insect visitors is much below that of the well-studied tropical forests of lower elevations. Data are presented on visitation rates by the tropical bumblebee Bombus ephippiatus to flowers of three species, pollen loads on bumblebee bodies, and pollen loads on stigmas of two of the species. High visitation rates to flowers of Palicourea brenesii were found, a species which produces copious amounts of nectar. Visitation rates to nectarless Leandra subseriata and Deppea grandiflora were much lower. Conspecific pollen comprised on average 90% of the pollen load on stigmas of Leandra, while Palicourea stigmas carried only 26 to 55% conspecific pollen. With only two ovules per flower, fruit and seed set in Palicourea were not limited by a shortage of conspecific pollen. In Leandra, 20–25% of the flowers received too few conspecific pollen grains for maximum seed set among 440 ovules per flower. Individual bumblebees showed no constancy in plant choice, judging from the high number of different pollen types (6–12) on their bodies. Workers returned frequently to the same Palicourea patch without visiting nearby Palicourea plants, which suggests the use of foraging paths.

Epiphyte diversity as well as distribution and composition of epiphytic biomass was investigated in two lowland and two montane rain forests in Ecuador. Species numbers of epiphytes per tree were slightly higher in the montane (22–41 in Los Cedros, 33–54 in Otonga) than in the lowland forests (9–43 in Yasuni, 19–32 in Tiputini), however differences were not significant. In contrast, some epiphyte families did show significant altitudinal differences. The total epiphytic biomass per branch surface decreased from the centre of the crown to the periphery, and was generally higher in the montane (6.0 kg m−2 on central branches in Los Cedros, 1.8 kg m−2 in Otonga) than in the lowland forests (1.3 kg m−2 in Yasuni and 1.8 kg m−2 in Tiputini). Especially, dry weight of bryophytes and dead organic matter was higher in the mountains. In contrast, the biomass of green parts of vascular epiphytes on central branches was about the same in all four forests (0.4–0.6 kg m−2). A comparison with literature data from other study sites of tropical moist forests supports the observation that biomass of vascular epiphytes does not significantly change with altitude. It is discussed, that the high bryophytic biomass in montane compared to lowland forests is a major reason for differences in humus biomass between these forest types.

A study was conducted on the effect of extended land-use on secondary forest biomass accumulation in the Amazon. Structural measurements were made in a series of secondary forest stands, from 4–30 y old, in Brazil and Bolivia. Half of the stands were forest regrowth following clearance and only 1 y of cultivation; the other half were regrowth following 4 y or more of continuous pasture in Brazil and three or more rotations of medium-fallow agriculture in Bolivia. Above-ground live biomass was estimated using published allometric equations. Total biomass ranged from 17 to 207 Mg ha−1. Biomass of pioneer trees was poorly related to stand age, while that of later-successional trees increased linearly with age. Total biomass accumulation in Bolivia averaged 5.4 Mg ha−1 y−1 over the entire age sequence. Biomass accumulation for regrowth following short-term use was not greater than that for regrowth following medium-fallow agriculture. In Brazil, biomass accumulation averaged 9.1 Mg ha−1 y−1 over the first 12 y of regrowth and 5.9 Mg ha−1 y−1 over the entire age sequence. Biomass accumulation was significantly slower, around 5.0 Mg ha−1 y−1, for regrowth following continuous pasture than for regrowth following 1 y of cultivation.

The feeding behaviour of free-ranging black-handed tamarins, Saguinus midas niger, was monitored over 6 mo in a forest fragment in eastern Amazonia. The tamarins' diet included arthropods and plant exudates, but was predominantly frugivorous (87.5% of feeding records, 18 plant species) in all months. The seeds of at least six species were ingested whole and defecated intact. Ingested seeds were relatively large, but those with diameter > 1 cm or length > 2 cm were discarded. Seeds took 2–4 h to pass through the digestive tract, and more than half (50.6%) were dispersed to a habitat different from that in which they were ingested. A fifth (19.3%) of all seeds were dispersed from primary to secondary forest, indicating that S. m. niger may play an important rôle in forest regeneration, a rôle that will become increasingly important in the fragmented landscape of eastern Amazonia.

Observations were made of foraging frequency and food selection by species of Macrotermitinae in a savanna habitat in the distal reaches of the Okavango Delta, Botswana. A removal experiment in the field was also conducted. Observable foraging showed seasonal peaks in frequency, related to temperature in Macrotermes michaelseni and to moisture in sympatric soil nesting Termitidae. Foraging was mostly on woody litter of the dominant canopy trees and mammalian dung. There was considerable overlap in the selection of food items between species but M. michaelseni were seen more frequently on items of woody litter greater than 6 mm in diameter. In Petri-dish trials Microtermes spp. workers were aggressive towards M. michaelseni individuals and in the field they foraged more frequently and effectively when M. michaelseni numbers were experimentally reduced. Macrotermes michaelseni appeared to avoid competition with other fungus-growing species by spatial separation within the habitat and some limited separation in food selection, but intense competition is probably rare as space and food resources may rarely be limiting.

Canopy observations of the rain forest tree Parkia velutina (Leguminosae: Mimosoideae) in Amazonian Brazil indicate that it is pollinated by night-flying bees. The small red flowers are organized into spherical heads; they open in the late afternoon and attract Megalopta bees (Halictidae: Augochlorini) which forage for pollen after dark. In contrast to the numerous bat-pollinated species of Parkia, no nectar was detected. Nocturnal melittophily is proposed as a possible intermediate stage in the evolution of chiropterophily from diurnal entomophily in Parkia.