This study assesses the impact of four fire treatments applied yearly over 3 y, i.e. early fire, mid-season fire, late fire and no fire treatments, on the grass communities of Lamto savanna, Ivory Coast. We describe communities of perennial tussock grasses on three replicated 5 × 5-m or 10 × 5-m plots of each fire treatment. Tussock density did not vary with fire treatment. The relative abundance of grass species, the circumference of grass tussocks and the probability of having a tussock with a central die-back, varied with fire treatment. Mid-season fire had the highest proportion of tussocks with a central die-back while the late fire had the smallest tussocks. Tussock density, circumference, relative abundance and probability of having a central die-back varied with species. Andropogon canaliculatus and Hyparrhenia diplandra were the most abundant of the nine grass species. They had the largest tussocks and the highest proportion of tussock with a central die-back. Loudetia simplex was the third most abundant species but was very rare in no fire plots. The distribution of tussock circumferences was right skewed and dominated by small tussocks. The proportion of the tussocks with a central die-back strongly increased with circumference, which could lead to tussock fragmentation. Taken together, this study suggests that fire regimes impact grass demography and that this impact depends on grass species and tussock size.

Determining the effects of light pollution on tropical bat communities is important for understanding community assembly rules in urban areas. Studies from temperate regions suggest that, among aerial insectivorous bats, fast-flying species that forage in the open are attracted to artificial lights, whereas slow-flying species that forage in cluttered environments avoid those lights. We measured aerial insectivore responses to light pollution in a tropical cloud forest to test this hypothesis. Bat echolocation was recorded at 20 pairs of light and dark sites in Monteverde, Costa Rica. Foraging activity was higher at artificially lighted sites than dark sites near the new moon, especially around blue-white fluorescent lighting. Most recorded bat species showed increased or unchanged activity in response to light, including some slow-flying and edge-foraging bats. This finding suggests that, contrary to the evaluated hypothesis, flight speed and foraging mode are not sufficient to determine bat responses to artificial lights in the tropics. Two bat species showed decreased activity at light sites, and a low species evenness was recorded around lights, particularly fluorescent lights, compared with dark sites. As in the temperate zone, light pollution in the tropics seems to concentrate certain bat species around human-inhabited areas, potentially shifting community structure.

Primates are important seed dispersers in natural ecosystems and agro-ecosystems, but the latter scenario remains under-studied. The degree to which primates favour plant regeneration greatly depends on post-dispersal processes. The main objective of this study was to compare patterns of seed/seedling fate and seedling recruitment in two habitats of the black howler monkey (Alouatta pigra Lawrence 1933), rustic cocoa and rain forest, and two types of seed-deposition locations, monkey latrines and control locations. Field experiments were carried out within the non-overlapping home ranges of six monkey groups, three in cocoa and three in forest. Seed and seedling fates were assessed for one focal tree species, Brosimum lactescens. The probabilities of seed survival (0.52), germination (0.72), seedling establishment (0.73) and early seedling survival (0.38) were not affected by habitat or seed-deposition location. Late seedling survival was similar in the two habitats but was higher in control locations (0.22) than in latrines (0.09). In cocoa, 4641 seedlings of 59 species were recorded, in forest 3280 seedlings of 68 species. Seedling recruitment was similar in both habitats, but latrines had higher densities than control locations. The importance of agro-ecosystems with low management intensity for the maintenance of ecological processes in anthropogenic landscapes is discussed.

Tree establishment in tropical dry forests is constrained by drought-related seedling mortality during early stages of recruitment. Predicted increases in the duration of growing-season droughts in the future pose a significant threat to these ecosystems that could significantly alter their vegetation structure and composition. Here, we examined drought tolerance in seedlings of seven common dry-forest tree species from the Indian subcontinent. We conducted a dry-down experiment on 3-wk-old seedlings, and asked whether the key plant functional traits, specific leaf area (SLA), leaf dry matter content (LDMC), seed size and stem specific density (SSD) were good predictors of seedling growth under well-watered conditions, and survival during drought. Seedlings displayed substantial drought tolerance with most seedlings surviving for more than 2 wk under protracted drought. Seed size in combination with SLA predicted seedling growth under well-watered conditions and seed size predicted survival under drought. In contrast to our expectations, seedlings with lower SSD survived for longer without water. Our results suggest that dry-forest species will be differentially affected by the predicted increases in the duration of growing-season droughts, and detrimental effects will be more severe for species with smaller seeds.

Staminodes are sterile stamens that produce no pollen, exhibit diverse structures and perform various functions. Flowers of Phanera yunnanensis possess three fertile stamens with large anthers and long filaments, and seven staminodes with tiny anthers and short filaments. To investigate the adaptive significance of staminodes in this species, we studied effects of staminode removal on pollen removal and deposition, flower visitation rate and fruit set in Xishuangbanna, south-western China. Four species of nectar-foraging pollinators visited flowers, mostly Amegilla zonata and Apis cerana (2.80 ± 0.15 and 1.76 ± 0.41 visits h−1 per flower, respectively). Staminode removal did not affect fruit set, but increased visitation by A. cerana by 2.6-fold, reduced visitation by A. zonata by 68% and increased the pollen removal rate for both pollinators (all effects were significant). Staminode removal significantly reduced pollen deposition rate for A. zonata, but not for A. cerana. These results suggest that the staminodes of P. yunnanensis filter which insects act as pollinators and affect pollen removal and deposition rates. By reducing pollen removal rates, staminodes may implement a pollen-dispensing schedule that spreads pollen dispersal from individual flowers over multiple pollinators. By altering pollen deposition rates, staminodes may influence reproductive fitness in other ways.

Caliochory, or seed dispersal by birds as nest material, has been reported for several species, but its effectiveness remains unclear in most cases. Darwin’s finches are traditionally regarded as seed predators, but the observation of two nests challenges this assumption by demonstrating that they can act as seed dispersers via caliochory. Darwin’s finches incorporate cotton-like materials into their nests, including seeds of Darwin’s cotton (Gossypium darwinii), a shrub endemic to the Galápagos (Ecuador). Bird nests typically break down after intense rainfall, so the seeds incorporated into nests might benefit from suitable conditions for germination. By simulating the germination conditions experienced over a 72-h period by cotton seeds in a naturally fallen nest, this study qualitatively confirms the long-term viability of at least a small fraction of the seeds at the surface of the nest. Darwin’s finches might therefore provide seed-dispersal services to Darwin’s cotton and possibly, other native and exotic plants of the Galápagos commonly incorporated into nests. However, larger confirmatory studies are needed.