1. 植物-昆虫相互作用
Plant-insect interactions

Various fruits found in a “General Flowering” event at Pasoh, Malaysia

A weevil feeding on dipterocarp seed

Insects occupy more than half of global biodiversity, overwhelming other taxonomic groups both in terms of number of species and biomass. In particular, insects are diverse in tropical forests and play a key role for maintaining the ecosystems by affecting reproduction and survivorship of plants and nutrient cycling. We are conducting researches on seed predators in tropical rainforests in Malaysia and Singapore to understand their importance as driving factors for evolution of flowering/fruiting phenology and species diversity of plants.

Hosaka et al. (2009) J Trop Ecol 25:625-636
Hosaka et al. (2011) J Trop Ecol 27:651-655
Hosaka et al. (2017) Biotropica 49:177-185, etc.

2. 林冠の生物多様性
Biodiversity at forest canopies

Canopy tower system at Pasoh, Malaysia

Survey on galling insects at tree crown 40 m above the ground

Tropical rainforest canopies, where leaves and flowers are most abundant, had been poorly studied due to its extreme height, often 30-50 m above ground, and called as an ecological frontier like deep sea. Recently, however, canopies have become more accessible due to construction of tower and crane at many study sites and spread of tree climbing techniques. We are conducting studies to reveal diversity of insects (such as galling insects) at forest canopies.

Takagi et al. (2005) Insecta Matsumurana New Series 62:123-151
Hosaka et al. (2009) Tropics 18:93-102, etc.

3. 森林管理と生物多様性
Forest management and biodiversity

Logged forest at Temengor, Malaysia

A dung beetle rolling dung ball

Because majority of tropical forests are managed not for protection but for timber production, biodiversity should be taken into consideration in managements of these production forests to conserve global biodiversity effectively. We are conducting studies on how timber logging and associated forest-road construction affect biodiversity (such as dung beetles and small mammals) and ecosystem functions of tropical forests, and how we can mitigate the negative impacts, toward sustainable forest management.

Hosaka et al. (2014) For Ecol Manage 326:18-24
Hosaka et al. (2014) Biotropica 46:720-731
Yamada et al. (2016) Biol Conserv 194:100-104, etc.

4. 人間―自然相互作用:生物多様性や自然景観に対する人々の意識,人間と野生生物の軋轢,自然ツーリズム
Human-nature interaction: People’s perception toward biodiversity and landscape, Human-wildlife conflict, Nature-based tourism

Sign board to avoid human-macaque conflict at Bukit Timah National Park, Singapore

Tourism development at Kuranda tropical rainforest, Australia

Nature conservation would be ultimately depending on people’s value for nature and willingness for conservation. Therefore, understanding people’s attitudes and perception toward nature is critically important for effective conservation planning. In particular, human-wildlife conflicts can often be an obstacle to conservation. We are conducting studies on people’s perception toward biodiversity and natural landscape and factors affecting the perception in tropical countries. We are also conducting studies on sustainable nature-based tourism as a tool for balancing human activities and ecosystem conservation.

Hosaka et al. (2016) Sci Rep 6:30911
Hosaka et al. (2016) Amer Entomol 62:228-234
Hosaka et al. (2017) Plos One 12: e0175243
Hosaka et al. (2018) Landsc Urban Plan 180:1-4, etc.

5. 都市の生物多様性とその保全
Urban biodiversity and its conservation

View of Kuala Lumpur city, Malaysia

“Nature” are not necessarily located in remote areas. We can also find various types of “nature” in suburban and urban areas. Today, urban areas are expanding and urban population is increasing rapidly worldwide, and in particular, developing countries which holds majority of tropical forests. Therefore, we conduct studies on how urbanization affects biodiversity and human-nature interactions.

Azmy et al. (2016) Urban For Urban Gree 18:117-125
Hosaka et al. (2017) Palgrave Comm 3:17071
Muslim et al. (2018) Ecol Process 7:18, etc