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In humid forests in Southeast Asia, many species from dozens of plant families flower gregariously and fruit synchronously at irregular multi-year intervals1–4. Little is known about how climate change will impact these community-wide mass reproductive events. Here, we perform a comprehensive analysis of reproductive phenology and its environmental drivers based on a monthly reproductive phenology record from 210 species in 41 families in Peninsular Malaysia. We find that the proportion of flowering and fruiting species decreased from 1976 to 2010. Using a phenology model, we find that 57% of species in the Dipterocarpaceae family respond to both drought and low-temperature cues for flowering. We show that low-temperature flowering cues will become less available in the future in the RCP2.6 and 8.5 scenarios, leading to decreased flowering opportunities of these species in a wide region from Thailand to the island of Borneo. Our results highlight the vulnerability of and variability in phenological responses across species in tropical ecosystems that differ from temperate and boreal biomes. A long-term analysis of phenological data from arboretums in forest research institute of Malaysia shows that flowering is triggered by low temperatures and drought. This historical dataset and future climate projections reveal how climate change is disrupting flowering phenology in tropical rainforests. [ABSTRACT FROM AUTHOR]

Direct experiences with nature in childhood are essential for enhancing psychological and physical development in children. However, researches on childhood nature-related experiences and their effects are largely biased toward more developed Western countries. In this study, we created a questionnaire on childhood experiences with nature and surveyed 357 adults (>20 years old) around Kuala Lumpur, the capital of Malaysia, to determine whether younger generations had fewer nature-based experiences than older generations and whether people who grew up in urban areas had fewer experiences than those who grew up in rural areas. We found that playing in rivers or waterfalls and collecting and eating tropical fruits were the most common nature-related activities experienced in childhood. There was a minimal decline in nature-related experiences among generations. However, people who grew up in rural areas had more nature-related experiences than those who grew up in urban areas. The loss of nature areas and increase in population density may accelerate the decline in nature-related experiences in urban areas. Therefore, efforts to create urban parks and other public spaces for reconnecting urban children to nature will become increasingly important for urban planning and environmental education in tropical developing countries such as Malaysia. [ABSTRACT FROM AUTHOR]

In the coastal waters of Johor Straits, Peninsular Malaysia, the dugongs occur and their habitat suitability model has yet not been attempted, while it could be critical information for developing their conservation strategies. This study derived spatially explicit dugong population information on the abundance and distribution of dugongs based on fisher surveys. The survey revealed the highest dugong abundance around eastern areas, followed by southern areas of Johor Straits. Degradation of seagrass habitat, which dugong uses as feeding ground, could be the main reason for reducing dugong sighting around western areas. A habitat suitability map was produced based on dugong presence and interacting environmental factors such as seagrass biomass, distance from shoreline, and water depth. Using ArcGIS mapping capability, the data layers on those environmental factors were fied into MaxEnt. The MaxEnt model output showed seagrass biomass as the highest contributing factor to the likelihood of dugong presence. The model also estimated 20 kg/m 2 of seagrass biomass, 3 km distance from shoreline and a water depth of 25 m as the optimum habitat condition for dugong population. The combination of fisher interview, habitat suitability, and risk modeling has the ability to provide adequate information required for monitoring and developing policy strategies for sustainable management and conservation of marine mammals. [ABSTRACT FROM AUTHOR]

Precise spatio-temporal measurements of rainfall during seasonal monsoons are critical for accurate hydrologic analyses in the tropical regions of Southeast Asia. The use of satellite precipitation data is technologically sound but requires downscaling to minimize inherent uncertainties. The uncertainties at a local climate regime that are essential to be resolved are rarely reported; consequently, such work needs attention. To address this problem, we validated the Tropical Rainfall Measuring Mission (TRMM) precipitation data using high-resolution areal precipitation (0.125 deg.) at a seasonal scale. This study examined the performance of the monthly rainfall data product (TRMM 3B43) at the seasonal monsoon scale in the local climate region of Peninsular Malaysia. The high-resolution areal precipitation data (0.125 deg.) were derived from a dense rain gauge network ever collected in Peninsular Malaysia (n = 984). Three relevant performance elements were evaluated: (i) the ability to depict temporal rainfall variation (ii) the quantitative error between TRMM and ground rainfall; and (iii) the ability to estimate the actual rainfall amount. We found that the ability of monthly TRMM data to depict rainfall variation and its tendency to propagate large errors varied seasonally. The correlation between TRMM and ground rainfall was good during the wettest period in all local climate regions. The error was related to the northeast monsoon and inter-monsoon 2 (September-October). Meanwhile, the TRMM ratio varied regionally, rather than seasonally. Determining the local-scale uncertainties will facilitate future downscale activities using TRMM satellite data in this region. [ABSTRACT FROM AUTHOR]

In South-East Asian dipterocarp forests, many trees synchronize their reproduction at the community level, but irregularly, in a phenomenon known as general flowering (GF). Several proximate cues have been proposed as triggers for the synchronization of Southeast Asian GF, but the debate continues, as many studies have not considered geographical variation in climate and flora. We hypothesized that the spatial pattern of GF forests is explained by previously proposed climatic cues if there are common cues for GF among regions. During the study, GF episodes occurred every year, but the spatial occurrence varied considerably from just a few forests to the whole of Peninsular Malaysia. In 2001, 2002 and 2005, minor and major GF occurred widely throughout Peninsular Malaysia (GF2001, GF2002, and GF2005), and the geographical patterns of GF varied between the episodes. In the three regional-scale GF episodes, most major events occurred in regions where prolonged drought (PD) had been recorded prior, and significant associations between GF scores and PD were found in GF2001 and GF2002. However, the frequency of PD was higher than that of GF throughout the peninsula. In contrast, low temperature (LT) was observed during the study period only before GF2002 and GF2005, but there was no clear spatial relationship between GF and LT in the regional-scale episodes. There was also no evidence that last GF condition influenced the magnitude of GF. Thus, our results suggest that PD would be essential to trigger regional-scale GF in the peninsula, but also that PD does not fully explain the spatial and temporal patterns of GF. The coarse relationships between GF and the proposed climatic cues may be due to the geographical variation in proximate cues for GF, and the climatic and floristic geographical variations should be considered to understand the proximate factors of GF. [ABSTRACT FROM AUTHOR]

Modelling based on paternity analysis of one hill and three lowland dipterocarp timber species in Malaysia indicated that more pollen donors sired progeny in Shorea leprosula and S. parvifolia than in S. curtisii and S. maxwelliana populations, because they start reproducing earlier. The relatively greater male fecundity of small S. leprosula and S. parvifolia trees also contributed to more rapid recoveries of outcrossing pollination following reductions in selective logging simulations. Furthermore, pollination by these trees significantly increases numbers of adult trees that contribute to mating as males, and hence maintenance of higher genetic diversity in S. leprosula and S. parvifolia populations. The variation in male fecundity of the dipterocarp species might be linked to variations in their turnover rates, wood density and (hence) optimal logging regimes. More specifically, species with low wood density (S. leprosula and S. parvifolia) grow faster, start reproducing at smaller sizes and can be harvested with the current selective logging protocol with minimal loss of diversity. In contrast, species with high wood density (S. curtisii and S. maxwelliana) grow more slowly, start reproducing at larger sizes and should be harvested with a less intensive protocol to maintain outcrossing pollination rates and genetic diversity in subsequent generations. The results showed that selective logging guidelines should be customised for specific groups of dipterocarp timber species according to their reproductive parameters and wood density. [ABSTRACT FROM AUTHOR]