Pollen and seed dispersal are key ecological processes, directly impacting the spatial distribution, abundance and genetic structure of plant populations; yet, pollen- and seed-dispersal distances are poorly known. We used molecular markers to identify the parental origin (n = 152 adult trees) of 177 Spondias radlkoferi (Anacardiaceae) seeds deposited by the spider monkey (Ateles geoffroyi) in latrines located beneath 17 sleeping-trees in two continuous forest sites (CF) and two forest fragments (FF) in the Lacandona rain forest, Mexico. We estimated mean parent-offspring (PO) distances per latrine and, for those seeds (54% of seeds) with more than one candidate parent (i.e. the potential maternal and parental parents), we also estimated parent-parent (PP) distances per latrine, and tested if PO and PP distances differed between forest types. Global PO and PP distances per latrine averaged 682 m (range = 83–1741 m) and 610 m (range = 74–2339 m), respectively, and did not differ significantly between CF and FF. This suggests that pollen dispersal is extensive in both forest types and that long seed dispersal distances (>100 m) are common, thus supporting the hypothesis that the spider monkey is an effective seed disperser of S. radlkoferi in continuous and fragmented forests.

Many plants within the neotropical understorey produce both seeds and clonal offspring. Plant attributes (i.e. size) and variability in light can influence seed dispersal but it is not known if these factors influence the dispersal of clonal offspring. Our goal was to determine if canopy openness and plant size influence clonal-offspring dispersal of the herb Goeppertia marantifolia, which produces clonal bulbils on above-ground shoots. We monitored plants in permanent plots with varying levels of canopy openness in Corcovado National Park, Costa Rica. We recorded canopy openness, leaf area and the distance clonal offspring travelled from their parent plant (N = 283). Our path analysis model demonstrated that canopy openness had a strong positive effect on dispersal distance, while the association between clonal-offspring dispersal distance and parent plant leaf area was only weakly positive. On average, plants experiencing high canopy openness dispersed their clonal offspring further than plants under low canopy openness (124 cm vs. 79 cm, respectively). Contrary to studies on species that utilize rhizomes and stolons for clonal reproduction, we found that in this bulbil-producing species light availability is positively associated with clonal dispersal distance. Therefore, the influence of resource availability on spatial population dynamics of clonal species may be influenced by the species’ growth-form.

To date, the spatial distribution pattern and density of Brazil nut trees in logged forest stands is unclear across the Amazon basin. We asked the following questions: (1) What are the densities and spatial distributions of Brazil nut juveniles (10 ≤ dbh < 40 cm) and adults (≥ 40 cm dbh) in three selectively logged Brazil nut concessions (1413 ha sampled) in Madre de Dios, Peru; (2) What is the spatial relationship between adults and juveniles (10 ≤ dbh < 30 cm); and (3) What is the spatial relationship between juveniles (10 ≤ dbh <30 cm) and cut stumps (≥ 10 y)? Spatial analyses were conducted using statistics derived from Ripley's K function. Juveniles were aggregated in all three concessions. Results for adult populations rejected the null hypothesis of a random distribution among trees ≥ 40 cm dbh. We did not find an attraction between juveniles and cut-stump locations, nor between adults and juveniles. The strong peaks of aggregation for juveniles and adult Brazil nuts in this study occurred at long distances (300–900 m), suggesting multiple tree canopy gaps as drivers of spatial distribution patterns, either via natural or anthropogenic sources. Our data contribute to a more thorough understanding of Brazil nut population structure in disturbed forests in south-western Amazonia.

Some species-rich secondary forests in New Caledonia have a monodominant canopy. Here we investigate growth and biomass allocation traits that might explain single-species’ dominance of these post-disturbance stands, and their later decline in the absence of large-scale disturbance. Seedlings of 20 rain-forest trees were grown in two light treatments in a nursery house. In the sun treatment, monodominants grew faster (56.7 ± 1.4 mg g−1 wk−1) than subordinates (40.2 ± 2.6 mg g−1 wk−1). However, some episodically regenerating (ER) subordinates had high growth rates similar to those of monodominants. In the shade treatment, monodominants and subordinates had similar growth rates (33.7 ± 2.6 and 34.0 ± 1.9 mg g−1 wk−1 respectively). Notably, monodominants in both sun and shade treatments had lower root mass fraction (0.29 ± 0.02 and 0.27 ± 0.02 g g−1 respectively) than subordinates (0.39 ± 0.02 and 0.37 ± 0.02 g g−1). Fast growth in sunny conditions is probably imperative for these relatively shade-intolerant ER monodominants. In field conditions, high shoot mass fraction combined with efficient root performance may facilitate faster growth in monodominants competing with other ER species in sunlit sites. Slower growth in shade may contribute to loss of dominance over time in undisturbed forests.

Patterns in above-ground biomass of tropical forests over short altitudinal gradients are poorly known. The aim of this study was to investigate the variation of above-ground biomass with altitude in old-growth forests and determine the importance of changes in floristic composition as a cause of this variation. We used a dataset from 15 1-ha permanent plots established from lowland (200 m asl) to submontane forests (900 m asl) in the Ngovayang Massif, south-western Cameroon. We analysed variation over altitude in two specific functional traits, the potential maximum tree height and the wood density. Forest above-ground biomass decreased from 500–600 Mg ha−1 in lowland plots to around 260 Mg ha−1 at the highest altitudes. The contribution to above-ground biomass of large-tree species (dbh ≥ 70 cm) decreased with altitude, while the contribution of smaller trees was constant. Contribution of the Fabaceae subfamily Caesalpinioideae decreased with altitude, while those of Clusiaceae, Phyllanthaceae and Burseraceae increased. While potential maximum tree height significantly decreased, wood specific gravity displayed no trend along the gradient. Finally, the decrease in above-ground biomass along the short altitudinal gradient can be at least partially explained by a shift in species composition, with large-tree species being filtered out at the highest altitudes. These results suggest that global change could lead to significant shifts in the properties of montane forests over time.

We studied lianas in a subtropical wet forest in Puerto Rico to understand how hurricane impacts and past human land-uses interact to affect liana dynamics over a 14-year period. We compared a high-intensity land-use area, where the forest that had been cleared, and used for subsistence agriculture before being abandoned in 1934 then regrew to a low-intensity land-use area, in which there had been only some selective experimental logging by the USDA Forest Service in the 1940s. Prior to our study, both areas were strongly affected by Hurricane Hugo in 1989, and again damaged to a lesser degree by Hurricane Georges in 1998, increasing canopy openness and subsequently increasing tree stem densities. Between 2001 and 2015, changes in the light environment and the recovery of forest structure resulted in roughly a 50% reduction in tree stem densities in the high-intensity land-use area, as recruited saplings naturally thinned. In this area, liana abundance increased by 103%, liana biomass tripled, and occupancy of trees by lianas grew by nearly 50%. In the low-intensity land-use area, juvenile stem densities were stable, and resultantly liana abundance only increased by 33%, liana biomass rose 39%, and the occupancy of trees was constant. Liana flower and fruit production increased over the 14-year interval, and these increases were much greater in the high-intensity land-use quadrats. Results of this study do show how rapid forest tree successional dynamics coincide with liana increases, but the confounding of hurricane effects of disturbance at our site, prevent us from asserting that the increases in liana density and biomass can be attributed to the same causes as those in forests elsewhere in the Neotropics.

Crypsis and aposematism are common antipredator strategies that can each be coupled with behaviours that maximize predator deterrence or avoidance. Cryptic animals employ camouflage to conceal themselves within their environment and generally rely on immobility to avoid detection by predators. Alternatively, aposematic animals tend to rely on an association between conspicuous colouration and secondary defence to deter potential predators, and tend to exhibit slow movements in response to predators. The goal of the present study was to determine how cryptic Craugastor sp. and aposematic Oophaga pumilio respond to simulated human and bird model predators. Oophaga pumilio responded more often with movement to both the human (17/22) and bird (9/25) predators than Craugastor sp. (human: 2/21; bird: 0/21). The increased movement resulted in a greater average flight initiation distance, latency to move, and distance fled in O. pumilio. These findings suggest that cryptic Craugastor sp. rely on immobility to avoid detection, whereas aposematic O. pumilio utilize movement, possibly as a mechanism to increase the visibility of their warning signals to potential predators. Furthermore, O. pumilio exhibited greater movement in response to humans, suggesting that they actively avoid trampling by large threats, rather than considering them predators.

We compared exotic pasture grass cover near the edges of 20–25-y-old secondary forests (N = 8) with those of mature forests (N = 8), bordering actively grazed pastures on the Pacific Coast of Ecuador. We estimated grass cover in 224 1 × 3-m plots along transects that ran from the pasture edge into forest interiors (11–44 m). Using a spline regression, we divided the transects into three segments: exterior (in the pasture), edge and interior (in the forest). With a stepwise regression, we tested the effect of transect section, forest type and distance from edge on grass cover. Forest type, distance from edge, interior transect section and the combined effect of distance from edge in both the interior and exterior sections explained variation in grass cover. Grass abundance was higher and penetrated further into secondary than mature forests. Edge proximity and differences in forest canopy openness likely favours recruitment and persistence of pasture grasses.

There is still much to learn about pollination ecology in areas of high species diversity, such as the Neotropical region. For example, the role of non-flying mammals in pollination is largely unknown in the Neotropical areas, despite the importance of this group in the pollination of plants in other regions. Here we report evidence for flower visitation by a rodent to Oreocallis grandiflora (Proteaceae) in our study site in the southern Andes of Ecuador. For a period of 241 h, camcorders equipped with infrared lights revealed 22 occurrences of floral visitation by Microryzomys altissimus (Cricetidae) to inflorescences of O. grandiflora. Pollen samples taken from the fur of captured individuals showed that M. altissimus carries pollen of O. grandiflora, indicating a potential pollinator role for the rodent. This is the first record of flower visitation by a rodent in the Neotropical Andes. Pollination interactions between non-flying mammals and Proteaceae have been reported in other southern hemisphere continents. This study underscores the need for more research on pollination interactions in the Neotropics, especially in critical Andean biodiversity hotspots.

Epiphytes represent keystone resources for many arthropod and vertebrate species, however their ecology remains poorly explored, especially within the palaeotropics. Several recent studies have examined relationships between epiphyte richness and characteristics of local habitats, although these have all focused on neotropical forests. Here, we aim to determine whether predictors of neotropical epiphyte richness are consistent at a palaeotropical site. A total of 44 host trees (dbh range 25–288 cm) were sampled at two study sites on Buton Island, Indonesia. For each tree, epiphyte richness and seven variables relating to characteristics of the host tree and surrounding habitats were recorded: site (a proxy value for disturbance level and water availability), host above-ground biomass (agb), altitude, bark texture, exposure, emergence and crown area. Gaussian GLM analyses indicated that the percentage deviance explained in epiphyte richness per host was greatest for agb (20.9%), crown area (19.6%) and site (15.5%); similar to previous findings from the neotropics. Results therefore suggest that high epiphyte diversity within palaeotropical forests is most likely to be found in large tracts of undisturbed forest, supporting large, broad-crowned trees.