Invertebrates

	Scale insects on wild fruits
	Where are Hong Kong's forest ants?
	A deep dark discovery

Where are Hong Kong’s forest ants?

by John Fellowes

You might think that most of the Hong Kong ant species are in your kitchen, but with over 170 recorded species in the SAR, the commensal species make up a small fraction of the whole. While Hong Kong is host to many wide-ranging tramp and invasive ants (Fellowes, 1999), and many that thrive in disturbed or exposed conditions, it also supports a large number of native forest-dwelling species that are not so adaptable. Many of these cannot be reliably assigned to a described species. They are confined mainly to slopes where remnants of natural forest have survived, in ravines and feng shui woods, or in some cases where forest has been restored. They include sites in the central Tai Mo Shan range: Tai Po Kau, Shing Mun Wood, Kadoorie Farm & Botanic Garden, Tai Mo Shan itself and Ng Tung Chai. They also include the Peak and Nam Fung Wood on Hong Kong Island; Sunset Peak and Pak Ngan Heung on Lantau; several sites on Ma On Shan and its foothills; Tit Kim Hang in the eastern New Territories; and Sheung Wo Hang in the northeast.

In general these forests are of known conservation importance to flora and other fauna (e.g. Corlett et al., 2000; Yip, 2000), and certain ant taxa probably depend on them for survival. Examples include arboreal genera (e.g. Gesomyrmex and Dilobocondyla) and species (Dolichoderus (thoracicus complex) sp. 3, Camponotus (nr. nipponicus) sp. 25, Camponotus (nr. humerus) sp. 31, Crematogaster (cf. ebenina) sp. 19 and Tetraponera nitida), as well as ground litter- or wood-nesting genera (Cerapachys, Acanthomyrmex, Aphaenogaster, Calyptomyrmex, Myrmecina, Rhopalomastix, Amblyopone, Centromyrmex, Discothyrea, Ponera and Probolomyrmex) and species (Aenictus (aratus group) sp. 5, Aenictus (dentatus group) sp. 4, Paratrechina (cf. opaca) sp. 26, Polyrhachis (mucronata group) sp. 13, Pheidologeton (cf. melasolenus) sp. 8, Pristomyrmex brevispinosus, Solenopsis sp. 7, Tetramorium (cf. curtulum) sp. 9, Leptogenys (cf. kraepelini) sp. 7, Leptogenys diminuta, Leptogenys (cf. emiliae) sp. 8, Leptogenys (cf. lucidula) sp. 10, Odontomachus (cf. silvestrii) sp. 3, Pachycondyla amblyops and Pachycondyla (cf. annamita) sp. 11). In all, some 65 (almost 40%) of Hong Kong’s recorded ant species might be described as forest specialists, apparently unable to survive in more open habitats. It is likely that more remain to be discovered.

Among larger vertebrates at least, forest specialists apparently did not survive past deforestation in Hong Kong (Corlett & Turner, 1997). Ant populations probably require smaller forest patches to persist, and Hong Kong’s forest fragments appear to have succeeded, among them, in retaining many of the forest specialists. Longer-term impacts of fragmentation, including those of invasive species in the degraded matrix, may have yet to kick in, but perhaps natural forest will be majestically restored before they do.

Bibliography

Corlett, R.T. & Turner, I.M. (1997). Long-term survival in tropical forest remnants in Singapore and Hong Kong. In: Tropical Forest Remnants: Ecology, Management, and Conservation of Fragmented Communities (eds. Laurance, W.F. & Bierregaard, R.O.). University of Chicago Press, Chicago, 333-345.

Corlett, R.T., Xing, F., Ng. S.C., Chau, L.K.C. & Wong, L.M.Y. (eds.) (2000). Hong Kong vascular plants: distribution and status. Memoirs of the Hong Kong Natural History Society 23: 1-157.

Fellowes, J.R. (1999). Exotic ants in Asia: is the mainland at risk? The case of Hong Kong. Aliens 9: 5-6.

Yip, J.Y. (2000). Conserving Biodiversity in Protected Areas: Recommendations for the Extension of Protected Areas in Hong Kong. Unpublished Report, Department of Ecology & Biodiversity, The University of Hong Kong, 14 + xxvii pp.

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