Casuarina Equisetifolia) Plantation on the Sand Skink (Eutropis Bibronii Gray 1839
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CORRESPONDENCE nators, Apis dorsata bees also foraged in success in true mangroves adapted to the lower parts of the flower and ac- ornithophily. cessed the nectar. But their pollen basket (Corbicula) remained empty. The bees also mopped the excess nectar oozing 1. Ollerton, J., Nature, 1998, 394, 726– from ovary adhering to the anthers and 727. calyx cup. It has been observed in the 2. Milet-Pinheiro, P. and Schlindwein, C., past that bees trigger the release of pol- Plant Biol., 2009, 11, 131–141. 3 len in ornithophilous species . However, 3. Kelly, D., Ladley, J. J., Robertson, A. W., we could not record any such instance in Edwards, J. and Smith, D. C., Nature, B. gymnorrhizha. It appears that bees 1996, 384, 615. were collecting nectar but not pollen. In- 4. Morris, W. F., Ecology, 1996, 77, 1451– 1462. terestingly, by early December the insect visitors had abandoned the study site, in- dicating migration to richer forage grounds. Such behavioural switching be- B. NAGARAJAN* Figure 3. An ant visiting to forage nectar tween robbing and legitimate pollination M. KRISHNAMOORTHY 4 in Bruguiera sexangula. in bees is known . Further, in B. sexan- S. PADMINI gula we noticed nectar robbery by ants A. DANIEL (Figure 3). In most of the opened flowers 3–5 ants were residing in the lower parts Institute of Forest Genetics and Tree 07:00 to 17:00 h and the duration of vis- of the ovary. In future, it would be inter- Breeding, its to individual flowers ranged about esting to study the implication of nectar Coimbatore 641 002, India 30–45 s. Like the legitimate avian polli- robbery by insects versus reproductive *e-mail: [email protected] Effect of casuarina (Casuarina equisetifolia) plantation on the sand skink (Eutropis bibronii Gray 1839) population Skinks are found in a variety of habitats like the tsunami that struck the coast on Our observations revealed that the worldwide embracing a wide geographic 26 December 2004. The monoculture average population abundance of E. distribution in the tropics. Eutropis planting of casuarina covered more than bibronii was significantly reduced from bibronii Gray 1839 (Scincidae, Squa- one third of the Tamil Nadu coast, which 21.00 ± 15.4 recorded in February–Dece- mata), a fossorial species (Figure 1 a) grew densely covering most of the beach mber 2006 to 9.00 ± 6.1 in March–June and named after Gabriel Bibron (1806– starting from the high tide line. Prior to 2007, which was probably due to 48) is diurnal in nature typically basking planting of the saplings, parts of the sand the stress created in their population during the day. It is found in the east dune with S. littoreus were burnt to because of burning of S. littoreus as well coast of Tamil Nadu in India, an habitat enable unhindered growth of casuarinas; as the shade provided by the casuarina of native herbs and creepers – such as but, a few patches of the original vegeta- plantation. The shade prevented the Spinifex littoralis that acts as sand bind- tion with the ground trailer S. littoreus skink population from basking like ers, a pioneering plant in the sand dune and were left unburnt, which provided before in their original habitat having S. ecosystem of the coastal areas. This a good microhabitat for E. bibronii. littoreus. In consistence with the present skink was previously assigned under the Though there are a few recent studies on findings, the casuarina plantations were genus Mabuya, but was later placed the effects of casuarina plantation on an reported showing adverse impact on the under the genus Eutropis after a taxo- endangered species of sea turtle – the olive ridley sea turtles by encroaching nomic revision1,2. They exhibited sexual olive ridley turtle (Lepidochelys oliva- upon the beaches, which visited east dimorphism with a red lining on the dorso- cea), little information is available on the coast beaches for nesting during January lateral side in males and a maximum lesser known reptile species such as E. to March every year as these beaches are number of hatchlings was sighted during bibronii inhabiting sand dunes and the their ideal nesting sites3. January. effects of casuarina plantation on its Nevertheless, due to widespread pro- The initiation of a World Bank project population. Hence we initiated a study to tests by conservationists of olive ridley during the summer of 2007 involved the find out whether casuarina plantation has sea turtles, the Tamil Nadu Forest De- planting of casuarina saplings (Casua- any effect on lizard populations in their partment was compelled to remove the rina equisetifolia) in the sand dunes of natural habitat of sand dunes at Vada- casuarina plantations up to a distance of the east coast (Figure 1 b) in order to nemmeli beach (12°44′N and 80°14′E) 45 m from the high tide line in October raise a protective plantation – a bioshield located 42 km south of Chennai, Tamil 2008 (Figure 1 c). Interestingly we obser- to blunt the impact of high sea-waves Nadu. ved that the removal of casuarina planta- 604 CURRENT SCIENCE, VOL. 98, NO. 5, 10 MARCH 2010 CORRESPONDENCE Figure 1. a, Adult male and female Eutropis bibronii. b, Saplings of Casuarina equisetifolia as seen in the winter of 2007. c, Sand dune after removal of plantation of C. equisetifolia. tion was favourable to the E. bibronii cies, E. bibronii inhabiting the coastal ATREE, Bangalore and MCBT, Mamal- increasing its population to about dune ecosystems in the long run. lapuram, India, 2009, p. 44. 16.6 ± 2.6 during February–March 2009, J. SUBRAMANEAN which was probably because of availabi- M. VIKRAM REDDY* lity of more suitable space for basking 1. Das, I. A., J. Herpetol., 1991, 25, 342–344. activity. It could also be attributable to 2. Das, I., De Silva, A. and Austin, C. C., Zootaxa, 2008, 1700, 35–52. Department of Ecology and the regeneration of the dead S. littoreus 3. Chaudhari, S., Devi Prasad, K. V. and Environmental Sciences, in the original places on the sand dunes Shanker, K., Impact of Casuarina Planta- Pondicherry University, where the skinks were found. Thus, it tions on Olive Ridley Turtle Nesting along Puducherry 605 014, India may help in the conservation of the spe- the Northern Tamil Nadu Coast, India, *e-mail: [email protected] FORM IV Particulars of Current Science—as per Form IV under the Rule 8 of the Registration of Newspapers (Central) 1956. 1. Place of Publication: Bangalore 4. Publisher’s Name, Nationality and Address: P. Balaram Indian Current Science Association, Bangalore 560 080 2. Periodicity of Publication: Fortnightly 5. Editor’s Name, Nationality and Address: P. Balaram Indian Current Science Association, Bangalore 560 080 3. Printer’s Name and Address: 6. Name and Address of the owner: P. Balaram Current Science Association Current Science Association, Bangalore 560 080 Bangalore 560 080 I, P. Balaram, hereby declare that the particulars given above are true to the best of my knowledge. Bangalore (Sd/-) 1 March 2010 P. Balaram Publisher, Current Science CURRENT SCIENCE, VOL. 98, NO. 5, 10 MARCH 2010 605.