The fruit-tracking hypothesis predicts a positive association between frugivores and fruit abundance over space and time. We documented hornbill diets and examined the relationship between fruit abundance and abundance of three hornbill species (Buceros bicornis, Rhyticeros undulatus and Aceros nipalensis) in the Eastern Himalaya from 2009–2012. The study was carried out at three scales: at the largest scale of the study area (15 km2), at the intermediate scale – eight 3-ha patches within the study area and at the smallest scale of individual fruiting trees. Ninety-one per cent of the 64 foraging sightings of the great hornbill were on figs while more than 50% of the foraging sightings of the wreathed (83) and rufous-necked hornbills (87) were on non-fig fruits. At the largest scale, wreathed hornbill abundance and ripe fruit abundance peaked in the non-breeding season. At the intermediate scale, wreathed hornbill abundance was positively associated with non-fig fruit availability while rufous-necked hornbill abundance was negatively associated with non-fig fruit availability. At the smallest scale, great and rufous-necked hornbill abundances were correlated with fig and non-fig fruit crop sizes, respectively. The three hornbill species track fruit availability at different scales based on diet, which has implications for their role in seed dispersal.

The spatial distribution of adult trees is typically not expected to reflect the spatial patterns of primary seed dispersal, due to many factors influencing post-dispersal modification of the seed shadow, such as seed predation, secondary seed dispersal and density-dependent survival. Here, we test the hypothesis that spatial distributions of primary seed shadows and adult trees are concordant by analysing the spatial distributions of adult Genipa americana trees and the seed shadow produced by its key primary disperser, the capuchin monkey (Cebus capucinus) in a tropical dry forest in Costa Rica. We mapped the dispersal of G. americana seeds by the capuchins during focal animal follows (mean = 463 min, n = 50) of all adults in one free-ranging group over two early wet seasons (May–July, 2005 and 2006). We mapped the locations of all G. americana trees within a 60-ha plot that lay within the home range of the capuchin group. We conducted multiple spatial point pattern analyses comparing degrees of clustering of capuchin defecations and G. americana trees. We found that adult tree distributions and primary dispersal patterns are similarly aggregated at multiple spatial scales, despite the modification of the primary dispersal patterns and long dispersal distances.

The response of vascular epiphyte communities following natural or human disturbance has been little studied. Over 5 y, we evaluated the post-stripping recolonization of vascular epiphytes in cloud forest. Vascular epiphytes were experimentally removed from branch and trunk plots (1 m in length) on five trees in two secondary cloud forest fragments in southern Mexico. Similarity between colonizer and established communities was compared in each fragment using a further five trees with no stripping. All seedlings were recorded yearly. Non-vascular epiphyte cover was estimated in each plot. The recolonization rate was very high; after 5 y, epiphyte density of the colonizer community (27.4 ± 6.8 individuals per segment) reached similar values to those of the established community (26.7 ± 3.3) in nearby trees. While similarity (composition and abundance) between the colonizer community and established community was high (81%), diversity accumulation curves indicated that the colonizer community presents a lower diversity of epiphytes (5.5 equivalent species) than the established community (11.4). Colonization of xerophytic bromeliads was high, while pteridophytes and orchids presented reduced recovery. The immediately surrounding source of propagules had a strong influence on recolonization. In both the colonizer and established communities, dominance rank was bromeliads > peperomias > pteridophytes. The results show that the recovery capacity of epiphytic vegetation in secondary forest is high, if propagule sources are close by. However, at 5 y after disturbance, it is unclear whether the colonizer community would present the same species composition as the established community or if it would give rise to a different community.

Anthropogenic edge effects, whereby disturbance strength increases in proximity to ecotone boundaries, are known to strongly affect individual species but we lack a general understanding of how they vary by species, disturbance type and regional context. We deployed 46 camera-trap stations for a total of 3545 trap-days at two sites in Sulawesi, Indonesia, obtaining 937 detections of five vertebrate species. Anoa (Bubalus spp.) were more abundant near edges, booted macaque (Macaca ochreata) and red jungle fowl (Gallus gallus) were less abundant near edges, and edges did not impact Sulawesi warty pig (Sus celebensis) or Malay civet (Viverra tangalunga). But the relative importance of habitat disturbance from agriculture, roads and villages differed for each species, and edge-induced disturbances varied not only in magnitude but also in direction between the study areas. In the strongest instance, macaque local abundance was 3.5 times higher near villages than it was 3 km into the forest in one reserve, but 2.8 times higher 3 km into the forest than near villages in the other reserve. Our results suggest that responses to habitat edges among species and edge types are idiosyncratic, and that landscape-level context can strongly alter the influence of local disturbance on biodiversity.

Juvenile tropical trees grow from the shaded understorey to the high-light conditions of the canopy, but actual height growth trajectories towards the canopy remain unknown. Although height growth is the determining factor for reaching the canopy, investment in diameter growth is needed to sustain mechanical stability. We quantified variation in long-term juvenile tree growth patterns in diameter and height within three Bolivian moist forest species, and evaluated whether diameter growth and height growth were related. We reconstructed lifetime growth in diameter and height for 21–27 juvenile trees per species by measuring tree rings at various heights in the stem. Growth in diameter and height strongly varied among and within tree species. The light-demanding species Cedrelinga cateniformis needed just 6–19 y to reach a height of 3 m, while the more shade-tolerant species Clarisia racemosa and Peltogyne cf. heterophylla needed 8–39 y and 13–43 y, respectively. Diameter growth and height growth were not, or just weakly, positively related, and trees of the same height displayed a wide range in stem diameter. Our results indicate that trees of all three species shifted investment in diameter growth and height growth over time, most likely in response to variation in light levels.

The ecological impacts of introduced species can reveal mechanisms underlying habitat selection and behaviour. We investigated the habitat use of native frog species and the invasive cane toads (Rhinella marina) in tropical northern Australia to measure overlap in habitat use, and to test if the presence of the cane toad influences frog behaviour. Native frog species and the cane toad both preferred habitats close to water and unvegetated holes. However, native frogs were found further from water (on average 19.4 m) than were toads (on average 12.6 m), and preferred areas with higher vegetation (8–50 cm) than did toads, which were more abundant in vegetation lower than 8 cm. For both types of anuran, the next neighbour was more often of the same type (89% in frogs, 52% in toads) than expected by chance (observed ratio: 75% frogs vs 25% toads), reflecting these differences in habitat use. Our counts of frog abundance increased on average 14.5% in areas from which we removed cane toads temporarily. This result suggests that cane toads inhibit the activity of native anurans either by inducing avoidance, or by reducing activity. By modifying the behaviour and spatial distribution of native taxa, invasive cane toads may curtail activities such as feeding and breeding.

Several monodominant rain-forest trees in New Caledonia have population size structures suggesting establishment following large-scale disturbance, with eventual replacement by shade-tolerant species predicted in the absence of future disturbance. Links of dominance and population dynamics to leaf-level photosynthesis were investigated in seedlings of 20 tree species from these forests, grown in experimental sun and shade conditions. In particular, we tested whether episodically regenerating (ER) species, including monodominants, have higher assimilation rates at high irradiances and lower tolerance of shade than continuously regenerating species (CR). ER species had higher maximum net assimilation rates (Amax-area) in sun plants (9.6 ± 0.4 μmol m−2 s−1) than CR species (6.2 ± 0.3 μmol m−2 s−1) and high plasticity, typical of shade-intolerant species, but monodominant species did not differ from other ER species. CR species had leaf-level traits consistent with shade tolerance, including lower dark respiration rates (Rd-area = 0.47 ± 0.03μmol m−2 s−1; Rd-mass = 7 ± 1 nmol g−1 s−1) than ER species (Rd-area = 0.63 ± 0.06 μmol m−2 s−1; Rd-mass = 11 ± 2 nmol g−1 s−1) in shade plants. Hence leaf-level assimilation traits were largely consistent with regeneration patterns, but do not explain why some shade-intolerant species can achieve monodominance.

Species showing mast seeding synchronously produce large amounts of fruits during some scattered years. This massive crop has been hypothesized to improve dispersal effectiveness by a satiation of seed predators, but the consequences for seed dispersers have barely been studied in the tropics. We tested the hypothesis that masting resulted in satiation of frugivorous dispersers using the study case of two Manilkara species growing in an Amazonian forest in French Guiana. Seed dispersal was estimated by means of seed traps in two forest types during a 10-y monitoring. Manilkara huberi and M. bidentata showed three fruiting events in a time span of 10 y (in 2001, 2006 and 2010). Estimates of seed dispersal from 2001 and 2010 showed that satiation of frugivores only occurred in the year with the largest crop of Manilkara (2010) and in the habitat where the diversity of primate-dispersed species retrieved in seed traps was the highest (Grand Plateau, with clay soils), while fruit consumers did not seem to be satiated in other instances. Spatio-temporal variability of seed production and the community-crop context are therefore affecting satiation of frugivores during masting events.

Balanites maughamii appears to be an obligate elephant-dispersed species. Its fruits are strongly scented and produce a large range of volatiles, particularly aliphatic acids such as hexanoic and isovaleric acid. The seed coat can resist a compression force of >1.5 kN. Seeds removed from the seed coat, and those from compressed seeds or from elephant dung, have better germination than seeds enclosed by undamaged seed-coats, which largely failed to germinate over a 2-mo period. Mastication by elephants may be necessary to split the seed coat to allow germination and the germinant to emerge from the seed coat. We identify four traits of elephant-dispersed fruits; they are dull-coloured, presented on the ground, strongly scented and have exceptionally strong seed coats.

This study compared the life histories of Hemidactylus frenatus, a significant invasive gecko, and Phyllodactylus palmeus, a Honduran endemic, over 10 wk, June–August 2013 at 12 study sites on the Honduran island of Cayo Menor of the Cayo Cochinos archipelago where H. frenatus arrived in 2008. Three different life-history traits related to invasion success were measured: body size, fecundity and population size. During the study 140 natives and 37 non-natives were captured, weighed, measured and marked uniquely. The number of gravid females and number of eggs were also recorded. Phyllodactylus palmeus was the significantly larger of the two species (60% larger mass, 25% longer SVL) and had higher population abundance at all 12 study sites with some sites yielding no H. frenatus individuals. However, H. frenatus had a larger proportion of gravid females. Observations that the native species is more common despite being sympatric with a known aggressive invader suggest two possibilities: the island is at the start of an invasion, or that the two species co-exist in a more stable fashion.

Annual rings are not commonly produced in tropical trees because they grow in a relatively aseasonal environment. However, in the subalpine zones of Hawaiʻi's highest volcanoes, there is often strong seasonal variability in temperature and rainfall. Using classical dendrochronological methods, annual growth rings were shown to occur in Sophora chrysophylla, a native tree species on Maunakea, Hawaiʻi. Chronologies were established from nearby non-native, live conifer trees and these were used to verify the dates from a total of 52 series from 22 S. chrysophylla trees, establishing an 86-y chronology (1926–2011). Ring-width patterns were significantly correlated with monthly rainfall from August of the previous year. This study is the first in the eastern tropical Pacific region to demonstrate annual growth rings in trees.