We examined the floristic composition and stand structure of tropical mountain forests containing two pine species, Pinus krempfii Lecomte and Pinus dalatensis Ferré, on the Da Lat Plateau in southern Vietnam. A total of 92 tree species were identified, and the greatest species richness at the family level was found in Lauraceae and Fagaceae. Both pine species grew to more than 25 m in height and spread their crowns over the continuous canopy layer. Under crowns of P. krempfii, Castanopsis chinensis, Trigonobalanus verticillata, Engelhardia roxburghiana, and Dendropanax hainanensis constituted the continuous canopy layer. Under crowns of P. dalatensis, pioneer species such as Schima wallichii, Exbucklandia populnea, and Pentaphylax euryoides along with gymnosperms such as Dacrycarpus imbricatus and Dacrydium elatum constituted the continuous canopy layer. Juveniles of P. krempfii were prevalent on the forest floor, but juveniles of P. dalatensis were scarce. We suggest that two pine species have different regeneration requirements related to disturbance and soil condition.

Landscape-scale habitat loss can change the floristic composition of forest fragments, affecting the survival of specific groups of plants, as shade-tolerant and emergent trees. This increasing in tree mortality creates forest canopy gaps of different sizes that ultimately determine the solar radiation available in the forest understorey. We conducted a study aiming to assess how the loss of forest cover at landscape level (i.e. deforestation) affects the sunfleck dynamics, a proxy of light regime in forest understorey. We expected that fragments located in landscapes with less forest cover have a high number of larger canopy gaps and, consequently, long-lasting sunflecks. In each forest fragment, a 100 per 50 m plot was established, and in each plot, we took 10 hemispherical photographs. The images were analysed using the Gap Light Analyzer software. The sunflecks were divided into six temporal classes. We evidenced that landscape-scale deforestation increased the frequency of all sunfleck intervals >8 min, particularly the long-lasting (> 32 min) sunflecks. We propose that the increasing frequency of long-lasting sunflecks reduces suitability of microhabitat to some shade-tolerant species in local fragments, a potential proximal mechanism contributing to compositional shifts of tree assemblages observed in forest fragments within deforested landscapes.

IPCC predictions for Honduras indicate that temperature will increase by up to 3–6°C and precipitation will decrease by up to 7–13% by the year 2050. To better understand how fern and lycophyte communities might be affected by climate change, we comprehensively surveyed the community compositions of ferns and lycophytes at Celaque National Park, the highest mountain in Honduras. We surveyed a total of 80 20 × 20 m2 plots along an altitudinal gradient of 1249–2844 m a.s.l., identifying all species and estimating their abundances. We recorded a total of 11,098 individuals from 160 species and 61 genera. Community composition was strongly influenced by changes in altitude, precipitation and the abundance of bryophytes (a proxy for air humidity). Of the 160 species, 63 are expected, under a RCP2.6 scenario for the year 2050, to shift their range fully or partially above the maximum altitude of the mountain. Of these, 65.1% are epiphytes. We found that species with narrow altitudinal ranges at high altitudes were more at risk. Our study indicated that conservation efforts should prioritise higher altitudinal sites, focusing particularly on preserving the vulnerable epiphytic fern species, which are likely to be at greater risk.

Sacred groves (SGs) of India are islets of forests providing ecosystem and spiritual services to man. Studies suggest that SGs are deteriorating on their quality due to urbanization, invasive species, land-use change, and religious modernization. We explored diversity, community, and abundance of overall and different functional groups of litter ants, including Anoplolepis gracilipes – an invasive ant – on paired SG-neighbouring home garden (HG) sites in rural and urban landscape to (a) assess the quality of SGs and (b) examine whether the variation in ant community of the two habitats was predicted by urbanization and abundance of A. gracilipes. We considered species and local contribution to β-diversity to identify species and sites crucial for conservation of sites. Abundance and richness of overall ants, proportional trap incidence of species, and abundance of A. gracilipes were similar on SG and HG, but species diversity and abundance of certain ant functional groups were higher on SG. Ant community of SG was different from HG, but was not affected by urbanization. A. gracilipes and rural SGs contributed the most to β diversity. A. gracilipes gave little pressure on native ant community. The study concludes that SGs, despite invaded by A. gracilipes, have potential for conserving biodiversity.

The frequency and intensity of harmful algal bloom (HAB) events have been increasing in many places around the world. Heterosigma akashiwo is a marine raphidophyte species known to cause HABs in many places across tropical and temperate climates. Studies of temperate strains have identified that H. akashiwo blooms are driven by mass activation of cysts which, for this species, can only form at <15°C temperatures. Although these temperatures do not occur in the tropics, there have been no comparative studies for tropical H. akashiwo. This study aimed to investigate whether tropical H. akashiwo can form cysts under warm temperatures, therefore having different responses from temperate strains. Results showed that tropical H. akashiwo were similar with temperate strains and could only form round cyst-like structures at 5°C but not 25°C. We also observed novel response of a decline and recovery in cell densities at 25°C. The decline was interrupted when the cultures were diluted, implying a tendency for H. akashiwo to rapidly spread and accumulate within surrounding waters, thereby facilitating blooms. This behaviour presents unique bloom concerns. Close monitoring of H. akashiwo distribution patterns is needed for better assessment of the bloom threat posed within tropical waters.

African monodominant forests are frequently formed by Gilbertiodendron dewevrei (De Wild.) J. Leonard and commonly found close to mixed forests. However, previous studies have ignored differences between these two forest types in height–diameter allometry, which is extremely important for aboveground biomass (AGB) estimates. This study aims to evaluate the performance of height–diameter models and their effects on height attributes and AGB estimations in African monodominant and mixed forests. Four 1-ha plots divided in 16 subplots (0.25 ha) were installed in each forest type in northern Republic of Congo. We measured diameter of all trees ≥ 10 cm diameter for each subplot and we measured the height of 264 trees over a large range of 7–64 m in two forest types. There was a significant difference in height–diameter allometry between two forest types and trees were taller and had greater AGB in monodominant forests than in mixed forests. Two height–diameter models from the literature generated the lowest error values when predicting tree height and AGB in mixed forests, whereas no model derived from the literature was appropriate for monodominant forests. The variation in height–diameter allometry between monodominant and mixed forests influences AGB estimates that have practical implications for carbon monitoring.