I investigated the extent to which adult butterflies with different wing colours display preferences for flying heights within a lowland tropical forest. Observations on eight colour groups, some of which comprised putative aposematic models and mimics while others contained nonaposematic species, were made from the forest floor and from a scaffold tower that reached above the canopy. Two groups (yellow pierids and papilionids and orange heliconiines) were most frequently observed in or above the canopy, and other groups were most frequently observed in or below the canopy. The evidence suggests that significant differences exist between some groups, but stratification does not occur among all colour groups. In particular, flight distributions of some mimicry rings overlap considerably. The light environments of different forest layers are variable, and the role that butterfly wing colours play in signalling or avoiding prcdation is little understood. However, the general lack of fine stratification of colour groups suggests that flight preferences do not occur because wing colours and patterns are especially cryptic against the background of particular forest layers.

Precipitation and temperature are known to have important effects on forest productivity, but these effects may be strongly mediated through their influence on soil and leaf nutrients. We measured indicators of forest productivity and soil and leaf nutrients across independent gradients of precipitation and elevation/temperature in lower montane Hawaiian forests dominated by a single overstorey species, Acacia koa, situated on 1500–3000-y-old soils that were mixtures of volcanic ash and basalt. Stand basal area was highest at the wettest site, 2000 mm mean annual precipitation (MAP), and leaf N and P were lowest at the driest site, 1000 mm MAP. Soil N availability and leaf N concentration declined across an 850-m elevation gradient, but this was not correlated with stand basal area or soil organic matter content. Across all stands, basal area was negatively correlated with the exchangeable soil P fraction. As well, the soil C:N ratio was negatively correlated with both soil P availability and the size of the primary mineral P fraction. Soil P availability and weathering appear to be important determinants of soil organic matter quantity and quality. Overall, precipitation is the major driving force for forest productivity, but P weathering and availability play important roles in limiting productivity in wetter sites and in controlling soil organic matter dynamics in these N-fixing forests.

Trees growing in a seasonally tropical dry forest, with its characteristic 5–7-mo rainless interval, possess a variety of physiological adaptations to drought, the most common being leaf abscission. At the Estacion Biologia de Chamela in western Mexico, we experimentally examined the relationship between one-time experimental irrigation ranging as 0 (control) to 200 mm, and (1) the degree of bud burst (and, for a single species, flowering), and (2) the formation of a false ring. Additionally, we used long-term records at a nearby meteorological station to determine the probability of a rain event exceeding a particular intensity (mm). For our seven species (particularly the two most common species: Cordia alliodora and Piptadenia constricta), we found that the degree of budburst and leaf extension was a function of irrigation intensity. In no case, however, did we find false rings, or indeed any indication of cambial activity initiated by the irrigation event. Further, there was no effect of intensity on subsequent relative growth rate in the following wet season. While sufficient rainfall (200 mm) to cause full leaf deployment is rare, nonetheless we estimate that a canopy tree in the study area would experience an event of this magnitude at least a few times per century. In any case, it will have no effect on the reliability of annual rings in this biome, nor any effect on diameter growth in (at least) the following year.

Spiders from 10 rainforest tree canopies in Borneo were sampled by knockdown insecticide fogging. Spider density ranged from 2.0 to 10.1 m−2 on different trees, and species numbers ranged from 16 to 62; species diversity, as measured by William's α, ranged from 26 to 92. Similarity of the spider assemblages on individual trees was low, whether measured by the number of shared species or the Morisita-Horn index of similarity.

The contribution of five descriptor variables of tree taxonomy and structure to the similarity of the spider assemblages on different trees was assessed using stepwise multiple regression. No variable made a significant contribution to the variation in similarity indices for the spider assemblages and it was concluded that either other factors were important in determining similarity or that the measurement of these variables was too imprecise. In particular, there was no evidence that taxonomic similarity between tree species influenced the similarity of spider assemblages.

Results were compared with similar data from tropical and sub-tropical rainforests in Sulawesi and Australia. Species densities in Borneo and Sulawesi were similar but lower than in Australia. Species richness and diversity were markedly higher in the Bornean rainforest than in Sulawesi or Australia.

In Hawaii, where there are no native reptiles or amphibians, 27 species of reptiles and amphibians have established (Kraus 2003); however, few have been studied to determine their ecological impacts. For example, little is known about the impacts of the Puerto Rican frog, Eleutherodactylus coqui Thomas, that recently invaded (late 1980s) (Kraus et al. 1999), and has established on all four main Hawaiian Islands (Kraus & Campbell 2002). However, there are likely to be consequences because E. coqui can attain high densities (20 570 frogs ha−1 on average in Puerto Rico) and consume large quantities of invertebrates (114 000 prey items ha−1 per night on average in Puerto Rico) (Stewart & Woolbright 1996).

In abandoned pastures where the seed bank of forest species has been depleted and a seedling bank does not exist, dispersal events are the only source of forest seeds for natural regeneration (Gómez-Pompa & Vázquez-Yanes 1981). Lack of dispersal has been reported as an important limitation for rain-forest regeneration in pastures (Hardwick et al. 1997 in Thailand; Holl 1999 in Costa Rica; Nepstad et al. 1990 in Brazil) or colonization of fallow land (Kollmann 1995). A high percentage of tropical plant species have fleshy fruits that are dispersed by birds and flying and terrestrial mammals (Howe & Smallwood 1982, Snow 1981). In this study we report the spatial distribution of fleshy-fruited species dispersed to tropical pastures at different distances from the vegetation border in 12 tropical pastures as a measure of the instant regenerative potential of these sites.

Floral trait correlations were compared between the two flower morphs of a distylous Ophiorrhiza napoensis population in a subtropical evergreen forest at the Defu Natural Animal Preserve, Guangxi, China. Common principal component analyses indicated that overall patterns in correlations among floral traits were morph specific in the study population. Strong positive correlations (r > 0.9) between anther height and corolla-tube length were found in both morphs. Stigma height correlated positively with corolla-tube length in the long-styled morph (r = 0.843), but not in the short-styled morph (r = −0.018). Flower-morph-specific correlation suggests that natural selection by pollinators has moulded trait covariance among floral traits. Because morph-specific correlations are expressed as the patterns of within-morph variation among multiple traits, putative genes responsible for the stigma-corolla tube correlation should not link to the supergene for sex-organ reciprocity between the morphs, but their expression is limited in the long-styled morph.

In Ethiopia, plantation forestry for soil conservation and wood supply is mainly based on exotic tree species harvested at 12–25-y rotation age. To evaluate if these forests truly represent ecological rehabilitation of degraded areas through the build-up of soil organic matter before harvest, relative abundances of C3 vs. C4 carbon in soils under a 25-y-old forest on Mt. Yegof have been studied based on changes in soil δ13C values due to vegetation cover changes by afforestation. At Yegof, shrub and tree leaves had δ13C value of −28.7 ± 0.4‰. The grasses showed a value of −30.7 ± 0.6‰ at 2700–3000 m asl (typical C3) and of −13.6 ± 0.3‰ at 2520 m asl (typical C4). Soil δ13C values were −21.7 ± 0.9‰ in soil at 0–5 cm and −20.7 ± 0.6‰ in soil at 30–50 cm indicating a long history of C4-dominated grass or cropland over the elevations sampled. The shifts towards lower δ13C values in soil at 0–5 cm coincide with 25 y of C3 vegetation. Carbon content in topsoil was 3.4–9.2% and in tree leaves was 45–56%. However, an estimate of new C3 carbon (54%) in 0–5 cm soil was low as compared with tropical rain-forest and savanna ecosystems suggesting a slow rate of carbon turnover at Yegof. The results suggest that degraded sites at Yegof may need further duration of forest cover longer than current rotation times of the forests to improve soil conditions and restore soil organic matter and carbon, which have been lost during the past land use. It is encouraging from the perspectives of ecological rehabilitation and soil conservation that a shift in the dominance from C4 vegetation types of agricultural and grassland ecosystems to C3 forest ecosystems could be established in less than 25 y on these highly degraded slopes of Mt. Yegof.

The Auchenorrhyncha community within the understorey of a montane monsoon rain forest in Vietnam is described. It was highly diverse, with 328 morphospecies in a sample of 1611 specimens. The community was variable in species composition with respect to space (between sites 1–5 km distant) and time (between early and late wet seasons). Differences in species composition attributable to spatial heterogeneity and to seasonal variation were of a comparable magnitude when examined by the CCA ordination. Auchenorrhyncha density, estimated by sweeping, was generally low, at 1 to 2 individuals m−3 of vegetation. There was a negative correlation between the species' population size in the early and the late wet seasons.

Trapping was conducted in primary and secondary forests to investigate the effects of past logging on small mammal communities. Thirteen I-ha sites were snap-trapped for three consecutive days in tropical monsoon rainforest in Xishuangbanna Nature Reserve, southern China. A total of 3900 trap-days yielded 198 captures, of which 118 were in the primary forest and 80 in the secondary forest. A total of 12 ground-dwelling species (eight Rodentia, Muridae; three Insectivora, Soricidae; one Insectivora, Erinaceidae) were caught, five (all Rodentia, Muridae) occurred in the primary forest and 11 in the secondary forest. The most abundant species was Niviventer confucianus, accounting for 62% and 39% of the total captures in the primary and the secondary forests, respectively. In the secondary forest the mean abundances of the two dominant species, N. confucianus and Maxomys surifer, were reduced, and a non-commensal form of Rattus rattus disappeared, but N. fulvescens showed no change while Mus pahari increased. The seven species which occurred only in secondary forest had very low abundance. Overall, the multivariate Mantel test showed the two communities to be significantly different. After logging, species diversity increased, and the two dominant species had increased body mass and their mean abundance decreased.

Increased shoot growth has recurrently been recorded following real or simulated shoot browsing, although responses may vary between different woody species. We investigated morphological responses to simulated dry-season browsing on Colophospermum mopane, Acacia tortilis, Grewia flava, Peltophorum africanum and Ziziphus mucronata, which differ in growth rate, occurrence of spines and use by mammalian herbivores. Treatment groups included a control, four clipping intensities and cutting at ground level. Responses were monitored during the following growth season on three annual shoots, located in the bottom, middle and top height interval, on each sapling. All five species showed compensatory growth responses, although no obvious relation was found between the strength of responses and growth rate or natural browsing pressure. The general pattern was an increased shoot length, shoot diameter, number of lateral shoots and shoot biomass with increased clipping intensity. These responses are probably an effect of the reduction of competing growing points and disrupted apical dominance. Growth responses were stronger in shoots with higher location on the sapling, which may reflect the pressure on saplings to attain a certain height to avoid browsing, reproduce and increase resistance to fire. We found no evidence of the number of spines being an induced defence in either of the two spinescent species studied.

1211 trees of 3 ft (0.91 m) girth or more were enumerated in 288 1-ch2 (about 400 m2) quadrats forming a 11.7 ha plot on the mainly Segamat soil series, Jengka Forest Reserve, Peninsular Malaysia, in 1964. Of the 261 taxa, 84% were identified to species. Five per cent of the area was of the permanently wetter Akob soil series. The plot was topographically flat and lay about 3 km west of the plot on the Batu Anam soil series, described in an earlier paper. Data on the chemical composition of the three soils are summarized here from a survey in 1967.

The vegetation on the Segamat series is of the Shorea-Dipterocarpus type of lowland dipterocarp forest. It has an unusually high abundance of the Euphorbiaceae (25% of trees) and a clear dominant species, Elateriospermum tapos. E. tapos, which regenerates profusely in the shade, grows up in small gaps and is strongly clumped, and appears well suited to the very friable, relatively nutrient-rich soil of the Segamat series, with lower soil-water holding capacity especially in dry periods.

Forest on the Segamat series is floristically very different from that on the Batu Anam series. This is most likely due to large differences in soil properties, the latter being of lower clay content, less nutrient-rich and, having a greater soil-water holding capacity at least in dry periods. It was dominated by Dipterocarpaceae.

Classification of quadrats on the Segamat series highlighted four classes; vegetation of the main E. tapos-dominated type on relatively dry soil (54% of plot area), vegetation on the wet Akob soil (21%), an association of shade-tolerant, mainly understorey trees beneath non-E. tapos-associated emergents (11%), and an association of long-lived, light-demanding pioneer trees of late-successional stages (11%); 3% of plot had no enumerated trees. Ordination showed that the plot was largely homogeneous with respect to edaphic factors but clearly displayed stages in forest succession.

The possible dynamics of the Segamat forest are inferred in terms of species autecology. Two hypotheses are advanced to explain the composition of the Segamat forest: (a) a dynamic equilibirum, (b) a non-equilibrium recovery from a recent catastrophe. The latter was thought more likely. Compared with the more benign Batu Anam environment, where co-dominants might be ‘ecologically equivalent’, the more selective soil conditions on the Segamat leads to reduced equivalence, with accidents of regeneration playing a smaller role in the local distribution of the most abundant species.

Eight species of Myzolecanium Beccari (Hemiptera: Homoptera: Coccoidea: Coccidae) are reported from ant nests in stem cavities of living lowland rain forest trees in Papua New Guinea. The coccids are confined to this microhabitat but are associated with a taxonomically broad range of ants and host trees. Attendant ants belonged to six species in three genera and two subfamilies: Anonychomyrma Donisthorpe (Dolichoderinae), Crematogaster Lund (Myrmicinae) and Podomyrma F. Smith (Myrmicinae). Host plants belonged to at least five families and included both apparently specialized (with domatia) and unspecialized species. Saplings containing the nests of Anonychomyrma scrutator (F. Smith), Anonychomyrma sp. 1 and Podomyrma laevifrons F. Smith were dissected and the structure of nest chambers and their contents recorded. Only some chambers had entrance holes, but many were interconnected by transverse passages. The coccids were in low numbers and fairly evenly distributed between ant-occupied chambers. The characteristics of the Myzolecanium-ant association, the role of the coccids as trophobionts, and the nature of the plant associations are discussed. Taxonomically, new combinations are proposed by P. J. Gullan for three species previously placed in Cryptostigma Ferris: Myzolecanium endoeucalyptus (Qin & Gullan), M. magnetinsulae (Qin & Gullan), and M. robertsi (Williams & Watson).

In contrast to their well-studied counterparts in the Neotropics and in Asia, East African montane rain forests are surrounded by semi-arid savanna plains. These plains have a high erosion potential for salt crusts accumulated at the soil surface. Hence it may be hypothesized that East African montane forest ecosystems experience strongly enhanced nutrient inputs via dry deposition, which alters their overall biogeochemistry. The aim of our study was to test this hypothesis by investigating K, Mg, Ca, Na and N-forms in rainfall, throughfall, fine litter, litter percolate and soil solution of a montane rain forest at Mt. Kilimanjaro. Four forest plots situated at elevations between 2250 and 2350 m asl on the south-western slopes of Mt. Kilimanjaro were studied for 2 y. In contradiction to our hypothesis, inputs of K, Mg, Ca and Na via rainfall (7.5, 0.9, 2.3 and 6.2kg ha−1y−1) and throughfall (35, 2.0, 3.5 and 11kg ha−1−1) were low on Mt. Kilimanjaro. Fluxes of NH4-N and NO3-N were within the range observed at other montane rain forests, with NO3-N being the only nutrient partly absorbed in the forest canopies (2.9kg ha−1y−1 in rainfall, 0.9kg ha−1y−1 in throughfall). The highest overall nutrient concentrations in water samples occurred in litter percolate (1.4mg l−1 K, 0.3mg l−1 Mg, 0.8mg l−1 Ca, 0.3mg l−1 NH4-N, 0.9mg l−1 NO3-N), with values still being low compared to other sites. Nutrient concentrations in seepage water strongly declined with increasing soil depth. Thus, both inputs and losses of base cations from the forest by water pathways are assumed to be low. N or P limitation of growth is not expected since high fluxes of N and P in fine litter (119 and 5.9kg ha−1y−1 for N and P respectively) indicate low within-stand efficiency.

The emphasis of antagonistic fungus–consumer interactions to date has been on temperate taxa and predominantly zoocentric, neglecting the effects on the fungal component. These interactions are expected to be especially complex and diverse in the tropics, where both components display their greatest diversity. Variability in fungivory (apparent biomass consumed) of understorey basidiomycetes in a tropical cloud forest was investigated to test whether this could be explained (at the proximate level) by apparency-related characteristics of the aboveground structures (colour of pileus, stipe and hymenium; size and aggregation), as has been suggested for plant–herbivore relationships. Considerable interspecific variation in fungivory was detected (range 0–50%). Cluster analysis showed that neighbouring clusters had dissimilar levels of fungivory. Such clusters were similar in colour attributes of aboveground structures, but differed in aggregation size and apparent biomass. A quantitative analysis also showed that colour attributes were not strongly associated with the observed variation of consumption levels, whereas apparent biomass and aggregation size did correlate with the observed variation in fungivory. Furthermore, specific identity correlated with fungivory. It was concluded that coloration patterns may not be important for fungivory, whereas genet size and species identity (probably via characteristics unrelated to apparency, such as mycotoxins and nutritional value) seemed to be critical factors.

Patterns of gene flow within 21 northern Australian populations of Syzygium nervosum a dominant, mass-flowering, monsoon rain forest canopy tree were investigated using 10 isozyme loci. S. nervosum was found to have relatively high genetic diversity within populations (He = 0.307, AP = 3.7, P = 65) but also to have significantly lower frequencies of heterozygotes than expected (Ho = 0.126) and high allelic fixation (F = 0.512). Heterozygosity and allelic fixation were not correlated with measures of genetic diversity within populations, nor were they correlated with rain forest patch size, plant size or population isolation. Within populations, trees, of the same genotype (at each loci tested) were significantly clumped at short distances (c. 20 m), whereas trees of unlike genotypes were negatively associated. S. nervosum trees however, were not clonal in origin and had unique multilocus genotypes. The results suggest that the high levels of homozygosity recorded are the result of restricted pollination, primarily among flowers within individual trees or among closely related neighbouring trees, rather than rectricted seed dispersal. High homozygosity, the large fruit crop produced by trees of this species and the lack of association between heterozygosity and plant size, indicate that, S. nervosum is self-compatible, its fecundity does not appear to be impaired by inbreeding depression.

Many frugivorous animals disperse seeds in their faeces (Corlett 1998, van der Pijl 1982), which may enhance the ability of secondary seed dispersers and post-dispersal seed predators to locate seeds (Andresen 2001, Chapman 1989, Feer 1999, Janzen 1982). By destroying and moving seeds these animals can radically alter the primary seed shadows generated by frugivorous animals and, consequently, have the potential to influence plant recruitment (Alcántara et al. 2000, Crawley 1992). Nevertheless, the influence of faeces on seed removal in South-East Asian forests has not previously been investigated and our knowledge currently comes from studies in Neotropical forests (Andresen 2001, Chapman 1989, Feer 1999, Janzen 1982).

Positive plant interactions have strong effects on plant diversity at several spatial scales, expanding species distribution under stressful conditions. We evaluated the joint effect of climate and grazing on the nurse effect of Croton wagneri, by monitoring several community attributes at two spatial scales: microhabitat and plant community. Two very close locations that only differed in grazing intensity were surveyed in an Ecuadorian dry scrub ecosystem. At each location, two 30 × 30-m plots were established at four altitudinal levels (1500, 2630, 1959 and 2100 m asl) and 40 microsites were surveyed in each plot. Croton wagneri acted as community hubs, increasing species richness and plant cover at both scales. Beneath nurses mean richness and cover values were 3.4 and 21.9%, and in open areas 2.3 and 4.5%, respectively. Magnitude of nurse effect was dependent on climate and grazing conditions. In ungrazed locations, cover increased and diversity reduced with altitude, while grazed locations showed the opposite trend. In ungrazed plots the interactions shifted from positive to negative with altitude, in grazed locations interactions remained positive. We conclude that the nurse effect is a key mechanism regulating community properties not only at microsite but also at the entire community scale.

The distribution of epiphytes differs between branches within tree crowns as well as within habitats. Where the original forests have been lost, shade coffee plantations can be important refuges for epiphytes, but are not suitable for all species. To understand what affects habitat quality, we transplanted 1440 seedlings each of two orchids, one, Lycaste aromatica, restricted to forests, the other, Jacquiniella teretifolia, common on trees in coffee plantations and in forests. Seedling mortality and growth were compared between three forests, three young and three old coffee plantations to test for differences between habitats and to analyse which habitat features affect growth and mortality. In J. teretifolia there was no clear pattern of habitat effect on mortality (c. 0.08 mo−1), but the production of new shoots was higher in coffee plantations than in forests. In L. aromatica, growth rates as well as seedling mortality increased over time. During the last census growth rates in forests (1.8 mm mo−1) were significantly higher than in old (0.9 mm mo−1) and young (1.2 mm mo−1) coffee plantations, and seedling mortality was about four times higher in old (0.10 mo−1) and young (0.11 mo−1) coffee plantations than in forests (0.025 mo−1), which may explain the natural absence of L. aromatica from coffee plantations. Mortality in L. aromatica at individual sites was negatively correlated with bryophyte cover on branches (Pearson r = –0.75) and positively with lichen cover (r = 0.70) and canopy openness (r = 0.75). Branch cover with non-vascular epiphytes, whether directly responsible by improving the water supply to epiphytes or indicative of differences in microclimate, may be a useful indicator of suitable habitats for vascular epiphytes.

In the Sahel during recent decades, anthropogenic disturbance and periods of drought have caused changes in woody species frequency. The internal water status of six coexisting species was analysed to estimate the importance of water constraints in this process. Predawn and midday xylem pressure potential and stomatal conductance were monitored monthly for two years. The relations between xylem pressure potential and transpiration made it possible to determine the hydraulic conductivity of the soil—plant system. Two types of results were obtained. First, there was considerable diversity in water status of the different species. Minimum predawn xylem pressure potentials (dry season) ranged from – 1.5 MPa to – 5 MPa depending on species, with interseasonal variation from 0.08 MPa to 2 MPa. Response to rainfall was very rapid (a few days) or very slow (several months). The three functioning types defined using these results were compared with the phytogeographical status of the species. Second, more specific phenomena were observed, (a) Some species (Balanites aegyptiaca and Boscia senegalensis) showed an imbalance between the predawn xylem pressure potential and the soil water status during the rainy season; (b) a sharp increase in xylem pressure potential was observed in deciduous species in the middle of the dry season; probably related to bud break; and (c) the water status was always favourable for Combrelum glutinosum. The few remaining individuals seem to benefit from very favourable subsoil water supply conditions.