Reuben Clements

Limestone Karsts of Southeast Asia: Imperiled Arks of Biodiversity

Abstract The overexploitation of the worlds biomes for natural products calls for the prioritization of biologically important ecosystems for conservation. Here we show that limestone karsts are “arks” of biodiversity and often contain high levels of endemism. Humans have exploited karsts for a variety of products and services, but unsustainable practices have caused population declines and extinctions among site-endemic taxa. Limestone quarrying is the primary threat to karst biodiversity in Southeast Asia, where quarrying rates exceed those in other tropical regions. Several socioeconomic, political, and scientific issues undermine the stewardship of these karsts. Mitigation of these problems will involve (a) better land-use planning to prevent karst resources from being exhausted in developing regions, (b) comprehensive assessments of a karsts economic and biological value before development, (c) improved legislation and enforcement to protect karst biodiversity, and (d) increased research and activities to promote public awareness of the importance of karsts and the threats facing them.

Forests reserved for rubber

Among the world’s tropical regions, Southeast Asia has the highest relative deforestation rate and, for many faunal and floral groups, very high proportions of endemic and threatened species (Sodhi et al. 2010). Malaysia – which lies within this region – should therefore be lauded for retaining nearly 60% of its land area under forest cover, to help sustain its rich biodiversity. However, tropical rainforests there and elsewhere still face manifold threats. Recently, Mann (2009) highlighted how rubber plantations are already gnawing away at natural forests across much of Southeast Asia. Now, it appears that because of a policy loophole, even Malaysia’s forest reserves will not be spared. Much of the remaining

Further twists in gastropod shell evolution

The manner in which a gastropod shell coils has long intrigued laypersons and scientists alike. In evolutionary biology, gastropod shells are among the best-studied palaeontological and neontological objects. A gastropod shell generally exhibits logarithmic spiral growth, right-handedness and coils tightly around a single axis. Atypical shell-coiling patterns (e.g. sinistroid growth, uncoiled whorls and multiple coiling axes), however, continue to be uncovered in nature. Here, we report another coiling strategy that is not only puzzling from an evolutionary perspective, but also hitherto unknown among shelled gastropods. The terrestrial gastropod Opisthostoma vermiculum sp. nov. generates a shell with: (i) four discernable coiling axes, (ii) body whorls that thrice detach and twice reattach to preceding whorls without any reference support, and (iii) detached whorls that coil around three secondary axes in addition to their primary teleoconch axis. As the coiling strategies of individuals were found to be generally consistent throughout, this species appears to possess an unorthodox but rigorously defined set of developmental instructions. Although the evolutionary origins of O. vermiculum and its shells functional significance can be elucidated only once fossil intermediates and live individuals are found, its bewildering morphology suggests that we still lack an understanding of relationships between form and function in certain taxonomic groups.

Up in the Clouds: Is Sustainable Use of Tropical Montane Cloud Forests Possible in Malaysia?

Perched atop misty mountains, tropical montane cloud forests are one of Earths most imperiled and neglected ecosystems. More than half of these forests occur in Southeast Asia; those in Malaysia are considered some of the best studied in the region. Malaysia has numerous mountains that are exceptionally rich in biodiversity and sustain numerous locally endemic species, but they are also threatened by expanding forestry, agriculture, infrastructure, and global warming. Malaysia serves as an excellent case study to illustrate the issues and challenges associated with tropical cloud forest conservation. We critically assess the current status of Malaysias cloud forests—focusing on their biological uniqueness and prospects for long-term survival—and propose conservation strategies for agricultural, forestry, tourism, and policy sectors to help conserve these endangered ecosystems. It is our hope that decisionmakers around the region can use our review to evaluate and improve their national strategies related to cloud forest conservation.