For many years this transition has been casually associated with the Isthmus of Kra (Fig. 1), which is actually 300 km further south at 10°30′N. Hughes et al. (2003) studied the avian Indochinese-Sundaic transition and found a significant turnover in bird species between 11°N and 13°N, just north of the Isthmus of

Kra; 152 species, or half the forest-associated species present regionally, have range limits in this area. In many genera, northern species are replaced with southern species with very little range overlap. In mammals, Woodruff and Turner (2009) also traced the transition to the northern third of the peninsula but, instead of a narrow zone of replacement near the Isthmus of Kra, they found (1) an area of the peninsula from 8–14°N with 30% fewer species than expected and (2) Indochinese and Sundaic species range limits clustered just north (14°N) and south (5°N) of this species richness anomaly. Elements of this pattern are NVP-HSP990 similar to those found independently by Cattulo et al. (2008). As in the plants, the faunal dissimilarity across the

mammal Indochinese-Sundaic transition is greater than that on either side of Wallace’s Line (Kreft and Jetz, in review). Comparable analyses of the magnitude and location of the zoogeographic transition in other phyla are still lacking but, as a broad generalization, reptiles, amphibians and butterflies exhibit similar patterns (references in Woodruff 2003a, b). The history of the Indochinese-Sundaic transition will be discussed more Galeterone Selleckchem VX-661 below. Biogeographic issues of relevance to conservation Documenting biogeographic patterns Any discussion of regional patterns must begin by noting the strengths and weaknesses in the underlying distributional database. Its great strengths lie in the richness of the species lists and the fact that observations of many taxa span 200 years. The two great weaknesses remain the geographic gaps in the survey work and the ad hoc nature of the

record keeping. Wars, insurgencies and inaccessibility prevented biological exploration of parts of the region for many years and survey work has been a low priority of regional governments. Parnell et al. (2003) HKI-272 in vitro provide an excellent quantification of the effects of collecting patterns on our knowledge of Thai plants. The probable extent of our ignorance is indicated by the description of hundreds of new species of vertebrates and plants in both Vietnam and central Borneo since 1992 (Sterling et al. 2006; World Wildlife Fund 2009). Similar surprises can be expected in Myanmar where the northern limits of the Sundaic biota cannot be considered known until the Tenasserim is surveyed. The other weakness in the regional distributional database is the lack of standardized record keeping at national levels. Although progress is being made (e.g., SAMD 2008; Scholes et al. 2008; GBIF 2009; Webb et al.