Secondary succession was studied in a Mexican cloud forest region along a chronosequence of 15 abandoned pastures (0.25–80 y). Our objective was to determine the effects of distance from the forest border on successional vegetation structure and woody species richness along the chronosequence. Vegetation structure similar to that of mature forests recovered over 40–50 y, both close to (0–10 m) and away from (40–50 m) the border. Total woody species richness was similar for both distances but species composition differed significantly. When primary forest species were analysed separately, basal area, height, abundance and richness were all significantly higher close to the forest border. Primary species such as Quercus spp. (barochorous-synzoochorous) and Carpinus caroliniana (anemochorous) had lower basal area, density and height away from the border than close to it. Secondary species such as Lippia myriocephala (anemochorous) and Myrsine coriacea (endozoochorous) did not differ in their rate of colonization between distances. The limitation of seed dispersal and establishment for primary woody species away from forest borders suggests that propagules need to be introduced to accelerate forest restoration.

The seed dispersal system of a neotropical tree, Cabralea canjerana (Meliaceae), was studied in two forested areas in southeastern Brazil. The first study site, Parque Estadual Intervales (PEI), is a 49,000-ha reserve composed mostly of old-growth Atlantic rain forest. The second site, Mata de Santa Genebra (MSG), is a 250-ha fragment of old-secondary semideciduous forest whose present bird fauna differs markedly from the original, in part as a consequence of forest fragmentation. At PEI 35 bird species ate the diaspores of C. canjerana. Black-tailed tityra (Tityra cayana, Tyrannidae) was the main seed disperser, but several other species were also important seed dispersers. In contrast, at MSG C. canjerana diaspores were eaten by 14 bird species. At this area, the red-eyed vireo (Vireo olivaceus, Vireonidae) was the most important seed disperser, but it was also a ‘waster’ which dropped seeds beneath parent plants, or carried them to sites unsuitable for germination. At PEI, exposed seeds on the forest floor were heavily preyed upon by rodents and insects. Insects destroyed mainly seeds deposited near to parent plants. Insect predation was less intense at MSG than at PEI. The rodent density at MSG was unusually small, and part of the post-dispersal seed predation may be done by terrestrial birds, such as doves and tinamous, which are especially common at MSG. Some of the differences recorded between the seed dispersal systems of C. canjerana at PEI and MSG may have been the result of the fragmentation and isolation of the latter area.

Fleshy fruits collected from abundant woody plants on the Accra Plains, Ghana, were fed to frugivorous species common in the area. Seeds of each plant species were retrieved from each frugivore species for germination trials, and ingested seeds compared to fresh seeds in germination percentage and rapidity. Altogether 85 plant X animal feeding combinations were attempted. In 73% of trials, ingestion did not affect germination percentage; the remain-ing trials were about equally divided between significant increases and decreases. Ingested seeds had significantly faster germination in 12%, and significantly slower germination in 8%, of the trials. Germination percentages in all samples of fresh seeds ( = 37%) did not differ signifi-cantly from those ingested seeds ( = 31%).

There was a significant association between the effect of ingestion on both germination rapidity and percentage (significantly increased, decreased, or neither) and the plant species involved; there was no such association between the effect of ingestion and the animal species. Animals had inconsistent and frequently negligible effects on germination. Two-way analyses of variance (plants X animals) of germination percentage and of germination improvement showed that plant species were a significant source of variation and animal species were not. The fleshy-fruited plants of this assemblage are not generally dependent upon animals for successful germination of their seeds.

Fog drip and related microclimatic factors were measured between January 1999 and December 2002 at a tropical seasonal rain forest in Xishuangbanna, South-West China. During the study period, the annual average fog drip was 89.4±13.5 mm (mean±1 SD). Fog drip contributes an estimated 5% of the annual rainfall, with 86% of the fog drip occurring in the dry season (November–April). Annual fog drip was negatively correlated with annual rainfall. Monthly variation in fog drip was also negatively correlated with monthly rainfall. Average daily fog drip was 0.38±0.27 mm d−1 for all days on which fog drip occurred. Daily fog drip was negatively correlated with minimum air temperature and positively correlated with mean above-canopy wind speed. The results indicate that fog drip is an important additional input of water to this seasonal rain forest during the dry season.

The mass of fine litterfall and nutrient circulation through litterfall were determined in four Melrosideros polymorpha/Cibotium spp.-dominated rainforests that differed in substrate age, parent material texture and annual precipitation on Kilauea and Mauna Loa volcanoes on the island of Hawaii. Three of the sites had rates of litterfall of 5.2 Mg ha−1 y−1; the fourth, which was on the most fertile soil, produced 7.0 Mg ha−1 y−1 of litterfall with higher concentrations of nitrogen and phosphorus. Tree ferns of the genus Cibotium cycled relatively large amounts of nitrogen, phosphorus and potassium through litterfall; their contribution to nutrient circulation was disproportionate to their mass in the forest, or in litterfall. The forest on the youngest substrate, which also had the lowest concentrations of nitrogen in litterfall, was fertilized with complete factorial combinations of nitrogen, phosphorus and a treatment consisting of all other plant nutrients. Additions of nitrogen increased the quantity and nitrogen concentration in litterfall during the second year following the initiation of fertilization, while no other treatment had a significant effect. Additions of nitrogen had no effect on litterfall mass or nutrient concentrations in the most nutrient-rich site.

We studied the seed dispersal ecology of the Neotropical pioneer tree Cecropia peltata L. (Moraceae) in tropical dry forest by documenting its (1) fruiting phenology, (2) rates of visitation by vertebrate frugivores, and (3) rate of recruitment of juveniles in different habitats at Santa Rosa National Park in northwestern Costa Rica.

At Santa Rosa, C. peltata is a common but patchily-distributed plant. Fruiting in females is seasonal, and fruit availability peaks in June through August (the early wet season). Females bear a few ripe fruit per day over a 4–5 month, fruiting period. At least 28 vertebrate species (15 diurnal and 13 nocturnal species) eat Cecropia fruit; equal numbers of ripe fruit are removed during the night and day. Owing to their more gentle treatment of seeds in the gut, birds and bats probably are more effective dispersal agents than monkeys. The recruitment rate of juveniles into already established populations was about 0.8 ha−1 y−1 compared with a rate of 176 ha−1 y−1 during the colonization of a cleared roadside.

This paper presents the quantities of macro-nutrients (N, P, K, Ca, Mg and S) released from the ground layer vegetation to the atmosphere during six experimental burnings, in a Brazilian open savanna, named ‘campo-cerrado’. The values were obtained by comparing the amounts of nutrients in the fuel and in the ash resulting after the burn, in three different seasons. On average, 20.6 kg of N, 1.6kg of P, 7.1 kg of K, 12.1kg of Ca, 3.0 kg of Mg, and 3.2kg of S ha−1 were transferred from the plant biomass to the atmosphere, representing mean percentages of 95% for N, 51% for P, 44% for K, 52% for Ca, 42% for Mg, and 59% for S. The burn season showed no significant influence on the amounts of nutrients transferred to the atmosphere. Some relationships involving the quantities of macro-nutrients released, fuel moisture, the combustion efficiency during the burns, and the initial standing biomass in the area were also tested. Comparing the average output of macro-nutrients to the atmosphere obtained in this study with their inputs via rainfall, in the same area, it was estimated that three years would be an adequate interval between prescribed burnings for this campo-cerrado, to speed up nutrient recycling without impoverishing the system.

The concept of ecosystem engineering has catalysed novel approaches and models for non-trophic species interactions and ecosystem functions. Ecosystem engineers physically modify abiotic and biotic environments, thereby creating new habitats that can be colonized by a new suite of species. In the Peruvian Amazonas, we tested whether peccaries (Tayassuidae) function as ecosystem engineers by creating and maintaining wallows. Such wallows could be critical aquatic habitats and breeding sites for anuran species during dry seasons. We compared hydroperiods of 21 peccary wallows and 13 naturally formed ponds across three dry seasons and found that wallows had a consistently higher mean water surface area than ponds. We also examined the pH, dissolved oxygen and temperature, and found no significant differences in these parameters between water bodies. Wallows had a significantly higher density of tadpoles, metamorphs and adult anurans, as well as higher β-diversity and species richness than ponds. This study not only provides the first systematic evidence of the ecosystem engineering processes of peccaries, but also reveals the positive consequences of such for anuran species.

Thirteen termite mounds and 13 similar-sized control plots were surveyed in central Zimbabwe in order to study large mammalian browsing and vegetation characteristics. The mounds supported almost twice as many tree species as the control plots and the woody vegetation was denser on mounds compared with the woodland plots. Species of woody plants were recorded along with the percentage of branches browsed (cumulative browsing score) by black rhino, Diceros bicornis, elephant, Loxodonta africana and other browsers combined. In addition we measured how the cumulative browsing score on three woody plant species, Acacia nilotica, Colophospermum mopane and Dichrostachys cinerea, which were common both on and off mounds, was related to the distance from mound centre. Both black rhino and elephant cumulative browsing scores were significantly higher on the mound plants compared with the woodland plots. Cumulative browsing score was negatively related to distance from the mound centre for Dichrostachys cinerea, Colophospermum mopane and Acacia nilotica. We propose that termite mound construction in miombo woodland contributes to sustaining populations of megaherbivores and perhaps some woody species in these areas.

ABSTRACT: Throughout the tropics there are a few hundred ant species that nest exclusively inside myrmecophytes (i.e. ant-domatia bearing plants). For these ants, nesting space is an essential resource that must be shared among them, therefore opening the possibility for strong intraspecific and interspecific competition. Several ant–myrmecophyte systems from Central Amazonia were investigated to test the relevance and generality of the nesting space limitation hypothesis for plant-ants. Empirical patterns were drawn at four organizational levels: (a) individual level—ant species with small-bodied queens were the most frequent partners of myrmecophyte species offering small-sized domatia, while ants with large-bodied queens dominated host species with large-sized domatia, suggesting that host choice by inseminated queens and interspecific conflicts over host dominance seem to be influenced by space limitation; (b) colony level—in eight independent ant–myrmecophyte systems, ant colony size was positively correlated to the number of domatia provided by the host, and the mean occupancy level of the domatia by ants was 92%, suggesting that space can be limiting to colony growth; (c) population level—ant colony number and distribution was determined by the local availability and distribution of its plant partners; and (d) community level—across ant-myrmecophyte systems, the commonness of ant species were largely determined by the commonness of their specialized host partners. Within ant-myrmecophyte systems, rarity of ants seems to be defined by interspecific conflicts over host dominance. The ecological and evolutionary consequences of those patterns are discussed.

RESUMO. Nos trópicos existem algumas poucas centenas de espécies de formigas que nidificam exclusivamente dentro de mirmecófitas (i.e. plantas possuidoras de domácias). Para estas formigas, o espaço de nidificação é um recurso essencial que precisa ser dividido entre elas, abrindo assim a possibilidade de competição intraespecífica e interespecífica forte. Diversos sistemas formiga-plantas da Amazônia Central foram investigados para se testar a relevância e generalidade da hipótese da limitação de sítios de nidificação para formigas associadas às mirmecófitas. Padrões empíricos foram gerados a quatro níveis organizacionais: (a) nível individual—espécies de formigas com rainhas de tamanho corpóreo reduzido foram os parceiros mais frequentes de espécies de mirmecófitas que oferecem domácias pequenas, enquanto que espécies de rainhas grandes dominam espécies de hospedeiros que oferecem domácias grandes, sugerindo que a escolha de hospedeiros por rainhas inseminadas e conflitos interespecíficos pela dominância do hospedeiro parecem ser influenciados por limitações de espaço; (b) nível da colônia—em oito sistemas formiga-plantas independentes, o tamanho da colônia das formigas foi positivamente correlacionado ao número de domácias oferecido pelo hospedeiro, e o nível médio de ocupação das domácias por formigas foi 92%, sugerindo que espaço pode estar limitando o crescimento das colônias; (c) nível da população—o número e a distribuição das colônias de formigas foi determinado pela disponibilidade local e distribuição dos parceiros vegetais; e (d) nível da comunidade—entre os sistemas formiga-plantas, formigas comuns e raras correspondem a aquelas especializadas respectivamente em espécies de mirmecófitas comuns e raras. Dentro de cada sistema formiga-planta, a raridade das formigas parece ser definida por conflitos interespecíficos sobre a dominância dos hospedeiros. As conseqüências ecológicas e evolutivas destes padrões são discutidas.

Changes in floristic composition and structure in a cerrado sensu stricto area were studied over a 9-y period. A sample of 19 (20-m × 50-m) permanent plots was assessed at 3-y intervals from 1985 to 1994, when all stems ≥ 5 cm at 0.30 m above the ground level were measured. There was little change in species composition over the period. Changes in density and basal area of the whole community were in the range of 5% over the 9 y. These parameters fluctuated over the years with the greatest differences found in the comparisons of 1991, 2 y after an accidental fire reached the site, with other years. The changes in density and basal area were greater than in several tropical forests, probably due to disturbances such as fire occurring at 3 to 5-y intervals. The nearly constant density and basal area suggested a highly resilient community.

Temporal variation in activity of dung and carrion beetles in tropical forest is considered as a mechanism of ecological segregation between potentially competing species. We describe the diel flight activity of Scarabaeidae collected with baited pitfall traps at Les Nouragues field station in French Guiana. A total of 2663 individuals of 63 species was recorded, from the subfamilies Coprinae, Scarabaeinae and Aphodinae. Temporal guilds of diurnal, nocturnal and crepuscular species were identified. Diurnal species were about twice as numerous and abundant as either nocturnal or crepuscular species. Two main activity patterns characterize the diurnal species while nocturnal and crepuscular species show overlapping activity. The association of activity rhythm with the other niche variables, food selection, functional group, body size and relative abundance, was analysed using multiple correspondence analysis. Small diurnal coprophagous species were opposed to large crepuscular necrophagous species. Species packing is suggested but further analysis showed that the variables were independent of one another. The temporal differentiation of species combined with separation along multiple niche dimensions and resource gradients may facilitate the coexistence of species assumed to be strongly affected by interspecific competition.

Phytotelmata habitats have been the focus of much research and are utilized by a wide variety of taxa. In the past 15 years numerous studies in many geographic regions and covering various types of phytotelmata have greatly increased our understanding of these unique habitats. The most recent summary of phytotelmata inhabitants included over 20 families of insects. A review of the literature and extensive work in lowland Ecuador shows the family level diversity is in fact at least twice that reported earlier. A reassessment of previous phytotelmata classification schemes, as well as an extensive bibliography, is provided.

The age of most temperate tree species can be estimated accurately by counting the annual rings revealed by concentric changes in their wood anatomy. In the tropics and sub-tropics, this growth periodicity is seldom clearly and unambiguously defined. This research investigates whether a wood anatomical feature is present that delimits annual periods in one of the most widely distributed genera in the semi-arid and arid areas of Africa, Acacia.

Most research on this topic has been based on sample trees from natural stands, often the largest and putatively oldest trees. In contrast, the trees sampled for this study were actively sought from material of known age, particularly those for which the history of management was known. Several African Acacia species were examined for growth rings. These were apparent in most species as narrow bands of marginal parenchyma filled with long crystal chains. The crystals were sub-sequendy identified as calcium oxalate through the use of a scanning proton microprobe. The number of bands formed annually corresponded to the number of peaks in the annual rainfall distribution. Ring widths were highly correlated with total annual rainfall.

An index of canopy closure was used to estimate closure above the crowns of all trees ≥ 10 cm dbh in 11.11 ha of undisturbed lowland tropical forest at La Selva, Costa Rica. To correct for the efFects of tree size on canopy closure, we used the residual of the regression of the canopy closure index on tree size. Analyses were carried out for the 104 species which had ≥ individuals; a total of 3224 trees were included. Nine species were found to have their crowns in significantly more open conditions than expected by chance and five species were found to have their crowns in significantly more closed conditions than expected by chance (P < 0.05). The remaining 90 species (86.5% of the assemblage) were distributed at random with respect to canopy closure, occupying the available light conditions indiscriminately. Species occurring under higher light levels did not show a narrower range of tolerance than did other species. Most species were found to occur over a substantial proportion of the canopy closure continuum present in the stand; overlap among the great majority of species in the assemblage is extensive. The results support the view that tropical forests comprise assemblages of generalist tree species, and raise questions about the classic notions of gap-phase dynamics.

We studied activity patterns and habitat use by insectivorous bats in Comoé National Park, Ivory Coast. Bat foraging activity was quantified along five transects representing three different habitat types using acoustic monitoring and captures with mist nets and harp traps. Aerial insect abundance was assessed using a light trap; in addition shrub and tree arthropods were sampled. Bat activity was significantly and positively related to insect availability and ambient temperature, whereas increased visibility of the moon had a negative influence on flight activity. Together, these factors best explained both total bat activity and activity of bats hunting in open space and edge habitats. The interaction between temperature and light intensity was the best predictor of activity by species foraging in obstacle-rich forest habitats, however, the regression model had a low predictive value. Overall, a large proportion (c. 50%) of the variation in bat activity appeared to be a consequence of transect- and/or habitat-specific influences. We found a significant non-linear relationship between the activity of QCF (quasi-constant frequency) and FM–QCF (frequency modulated – quasi-constant frequency) bats and the phase of the moon, with lowest levels of activity occurring near full moon. We interpret this lunar-phobic behaviour as a reflection of a higher predation risk during moonlit periods. For FM (steep frequency modulated) and CF (constant frequency) bats, no significant correlation was found, although there was a trend suggesting that these bats at least were not negatively affected by bright moonlight. Foraging activity of bats was positively correlated with the abundance of atympanate moths; however, no such correlation was found for tympanate moths.

The Kibale Forest, western Uganda, is the only site where studies have compared the impact of elephants on rainforest regeneration in logged and unlogged control areas. Elephants used heavily logged areas more than lightly logged and unlogged areas. Forest gaps were used more by elephants than closed-canopy areas and large gaps more than small ones. Gaps were larger in logged than unlogged forest. There were lower densities of young trees (saplings and poles) and a higher incidence of elephant damage to them in heavily logged forest than in lightly logged and unlogged sites. Elephant use of an area and damage to young trees was inversely or unrelated to the density of young trees and directly related to the density of herbaceous tangle. Heavy logging resulted in large areas of herbaceous tangle, which attracted elephants who suppressed forest regeneration by damaging young trees and perpetuating the herbaceous tangle. The tangle directly competed with regeneration of young trees while also attracting elephants and rodents (seed and seedling predators) and facilitating increased windthrow of trees. Selective browsing of young trees by elephants affected rates of regeneration, growth form and species composition. Rather than remove elephants, a more effective and humane approach to long-term management of logging is to reduce logging offtake and incidental damage caused by timber extraction.

The mechanism of general flowering in Dipterocarpaceae in the Malay Peninsula is revealed through field survey and meteorological data analyses. The regions of general flowering coincide with those which experienced a low night-time temperature (LNT) c. 2 mo before flowering. This supports the hypothesis that low air temperature induces the development of floral buds of dipterocarps. LNT was found to be caused by radiative cooling during dry spells in winter when the northern subtropical ridge (STR) occasionally migrates southwards with a dry air mass into the equatorial region. LNT events usually occur in La Niña episodes, not in El Niño episodes as believed previously. This is because the southward migration of the STR is associated with the intensification of local meridional Hadley Circulation in the western Pacific, which is strengthened in a La Niña episode. Results suggest that El Niño-like climate change in increased atmospheric carbon dioxide concentrations may be critical for the tropical rain forest biome in south-east Asia.

Litterfall was sampled during one year in two undisturbed Andean forests at altitudes of 2550 and 3370 m in the Colombian Cordillera Central. Total small litterfall at 2550 and 3370 m was 7.03 and 4.31 tha-1 y-1 respectively, of which 4.61 and 2.82 were leaves, 1.06 and 0.76 woody parts, 0.66 and 0.27 reproductive parts, 0.22 and 0.23 epiphytes, 0.47 and 0.23 unclassified.

Clear differences were also found in nutrient concentrations, both between different litter fractions from one site and between equivalent litter fractions from different sites. Weighted mean concentrations for total small litterfall were (mgg-1, at 2550 and 3370m respectively): 11.7 and 7.3 for nitrogen; 0.86 and 0.44 for phosphorus; 8.4 and 3.1 for potassium. Comparison of nutrient concentrations in crown leaves and shed leaves indicated important reallocation of nitrogen (39% at both sites) and phosphorus (45% at 2550m, 65% at 3370m) before leaf shedding.

The results for litterfall amounts, litter nutrient concentrations and reallocation of nutrients in the two forests are consistent with such data obtained in other montane forests in the wet tropics.