“Small mammals” are a highly diverse, non-taxonomic group, with an astounding range of adaptations and life histories, from the fishing mice of South America and the river-dwelling desmans of the Pyrenees and southern Russia, to the venom-injecting solenodons of the Caribbean. Generally some members of these groups are very poorly studied – many hundreds of species have never been photographed in the wild and even their basic ecology is unknown. Much of the diversity of the small mammals is undiscovered, including many new species yet to be described in regions like Indonesia, Philippines and Papua New Guinea. There are still completely new species and even genera to be found like the new genus and species of shrew rats that was found by Esselstyne et al. in northern Sulawesi in 2015. Southeast Asia supports a huge diversity of small mammals which play an important role in terrestrial ecosystems e.g. as seed dispersers in the regions forests (Herrera 2009). They are also a key link in the food chain, with many species preying on insects and other invertebrates, whilst themselves being preyed upon by larger predators (Carey & Johnson 1995). During the Indobiosys project we focused on the orders Rodentia, Scandentia and Eulipotyphla. These three orders contain more than 2800 species, of which 437 are considered threatened with extinction by the International Union for the Conservation of Nature (IUCN 2016).
Rodents are the world’s largest and most successful group of mammals. There are over 2200 living species, comprising around 40 percent of all of the mammal species existing today. They can be found throughout the world except Antarctica, New Zealand, and some oceanic islands (Myers 1999). Because of their excellent adaptability they have colonized many different habitat types in the course of evolution resulting in their high diversity (Harris & Yalden 2008). All Rodent species captured in the Halimun Salak National Park belong to the family Muridae. Maxomys bartelsii (Bartels's spiny rat. Pic.) was captured a lot in Gunung Gede. It is endemic to montane forests on volcanos of west and central Java (Carleton & Musser 2005).
Eulipotyphla comprises the Erinaceidae, Solenodontidae, Talpidae and Soricidae. In Halimun Salak only members of the Erinaceidae and Soricidae were captured. The first represented by Hylomys suillus (Short-tailed gymnure. Pic.), a small spineless hedgehog, with a rather broad distribution in Southeast Asia. The last represented by different species of Crocidura. Crocidura monticola (Sunda shrew. Pic.) was the most commonly captured mammal during the Indobiosys field phase, but also Crocidura brunnea (Thick-tailed shrew. Pic.) was trapped.
To get a deeper insight into the small mammal fauna further investigations need to be undertaken. Especially the arboreal species demand special capture techniques and elusive species can often only be reported after several years of intensive research (Brooks et al. 1998).