JoTT R E V I E W 4(11): 3029–3037 Land snaffs (Moffusca: Gastropoda) of Indfa: status, threats and conservatfon strategfes Sandeep Sen 1 , G. Ravfkanth 2 & N.A. Aravfnd 3 1,2,3 Surf Sehgaf Centre for Bfodfversfty and Conservatfon, Ashoka Trust for Research fn Ecofogy and the Envfronment (ATREE), Royaf Encfave, Srframpura, Jakkur PO, Bengafuru, Karnataka 560064, Indfa Emaff: 1 [email protected], 2 [email protected], 3 [email protected] (correspondfng author) Date of pubffcatfon (onffne): 26 September 2012 Abstract: Land snaffs form an fmportant component fn the forest ecosystem. In terms Date of pubffcatfon (prfnt): 26 September 2012 of number of specfes, the phyfum Moffusca, to whfch fand snaffs befong, fs the fargest ISSN 0974-7907 (onffne) | 0974-7893 (prfnt) phyfum after Arthropoda. Moffusca provfde unfque ecosystem servfces fncfudfng recycffng of nutrfents and they provfde a prey base for smaff mammafs, bfrds, snakes Edftor: Fred Naggs and other reptffes. However, fand snaffs have the fargest number of documented Manuscrfpt detaffs: extfnctfons, compared to any other taxa. Tfff date 1,129 specfes of fand snaffs are Ms # o2722 recorded from Indfan terrftory. But onfy basfc fnformatfon fs known about thefr taxonomy Recefved 03 March 2011 and ffttfe fs known of thefr popufatfon bfofogy, ecofogy and thefr conservatfon status. In Ffnaf recefved 18 Jufy 2012 thfs paper, we brfefy revfew status, threats and conservatfon strategfes of fand snaffs Ffnaffy accepted 24 August 2012 of Indfa. Cftatfon: Sen, S., G. Ravfkanth & N.A. Aravfnd (2012). Land snaffs (Moffusca: Gastropoda) of Keywords: Bfodfversfty, conservatfon, fand snaffs, taxonomfc bfas, refntroductfon, Indfa: status, threats and conservatfon strategfes . Western Ghats Journaf of Threatened Taxa 4(11): 3029–3037. Copyrfght: © Sandeep Sen, G. Ravfkanth & N.A. Aravfnd 2012. Creatfve Commons Attrfbutfon INTRODUCT ION 3.0 Unported Lfcense. JoTT affows unrestrfcted use of thfs artfcfe fn any medfum for non-proft purposes, reproductfon and dfstrfbutfon by provfdfng adequate credft to the authors and the The tropfcs have faced massfve bfodfversfty foss due to fntensfve source of pubffcatfon. anthropogenfc actfvftfes such as changes fn fand use and degradatfon of Author Detaffs: See end of thfs artfcfe envfronment. Recent reports suggest that the tropfcs are fosfng bfodfversfty Author Contrfbutfon: Aff authors have at an afarmfng rate (Sodhf 2008). Much of thfs bfodfversfty foss has contrfbuted equaffy to thfs manuscrfpt been reported for vertebrates and pfants. However, there fs very ffttfe Acknowfedgements: The authors greatfy knowfedge on the extent of foss fn fesser known groups, especfaffy the acknowfedge the Darwfn Inftfatfve vfa DEFRA, Government of UK for fundfng. We are afso fnvertebrates. In thfs paper, we hfghffght the fmportance of fand snaffs gratefuf to Drs. T. Ganesh, Soubadra Devy and the need for thefr conservatfon. and K.V. Gururaja for crftfcaf comments on the earffer versfon of the manuscrfpt. We afso Land snaffs fncfude severaf dfstfnct ffneages of terrestrfaf gastropods thank two anonymous revfewers for thefr crftfcaf comments that greatfy hefped fn fmprovfng the and befong to the second fargest phyfum after arthropods fn terms of manuscrfpt. number of specfes wfth more than one fakh descrfbed specfes (Lydeard et af. 2004). Land snaffs constftute about sfx per cent of the totaf specfes on Earth (Cfark & May 2002). A farge part of moffuscan fauna fn many tropfcaf regfons of the worfd fs stfff poorfy known. They form an fmportant component of the forest ecosystem by recycffng nutrfents (Gravefand et af. 1994; Dunk et af. 2004) and are the prey base for a number of smaff mammafs, bfrds, reptffes, amphfbfans and other fnvertebrates, fncfudfng carnfvorous snaffs (Deepak et af. 2010). In cafcfum poor habftats fand snaffs can form an fmportant source of cafcfum for other anfmafs. Land snaffs afso serve as an fndfcator of ecofogfcaf condftfons, and are very sensftfve to cffmatfc and ecofogfcaf change (Shfmek 1930; Sfmone 1999; Čejka & Hamerfík 2009 ). Thus, they are usefuf for reconstructfng past envfronments (Bar-Yosef Mayer 2002; Gümüş 2009). As earfy as 1839 Charfes Darwfn showed the vafue of fand snaffs fn studyfng OPEN ACCESS | FREE DOWNLOAD envfronmentaf change (Naggs et af. 2006). Terrestrfaf snaffs prove to be Journaf of Threatened Taxa | www.threatenedtaxa.org | September 2012 | 4(11): 3029–3037 3029 Land snails of India S. Sen et al. valuable research subjects for studies in evolutionary These malacological pioneers laid the foundation of biology, biogeography, phylogeography, biodiversity, our knowledge on the taxonomy and distribution of ecology and conservation biology (Schilthuizen et Indian land snails. Following this period of intensive al. 2007; Davison et al. 2008; Richards & Davison study, there was a drastic decline in studies on Indian 2010). With their generally low dispersal powers, land snails. More recent studies in India, have mainly land snails tend to exhibit conservative distribution concentrated on inventorying regional snail faunas patterns, making them valuable subjects in studying (like state or protected areas) and less on species historical biogeography (Solem 1984; Naggs & description, ecology and conservation (Aravind et Raheem 2005; Wade et al. 2006). Highly diverse and al. 2010). While globally, there has been a renewed narrowly distributed, land snails are good indicators interest in land snail research, in India the research has of areas of conservation importance and endemicity truly been at a snail’s pace (Aravind et al. 2005, 2008, when compared to widely distributed groups such as 2010; Aravind & Naggs 2012). Little information is vertebrates (Moritz et al. 2001). available on species limits, distribution ranges and The distribution and activity of land snails depends patterns of diversity. Recent analysis of Indian land on several factors including precipitation, soil pH, soil and freshwater molluscan literature has confirmed Ca content, canopy density, etc. Calcium availability that that there are hardly any studies on the ecology in the soil is a major limiting factor for their survival and conservation of Indian land snails compared to as it is required for their shell formation. Several the wide range of historical literature available on studies have shown that Ca is positively correlated taxonomy (Aravind et al. 2010). There are no studies with species richness and density (Burch 1955; Hotopp on the population status, phylogeny and taxonomic 2002; Aravind 2005). However, in the regions such as revision of different families or genera of Indian land the Western Ghats, where the soil is usually acidic the snails. snail richness is usually high but abundance is low. The past two decades have seen a large number of Species diversity and rarity in land snails studies highlighting the need for mollusc conservation Globally, nearly 35,000 species of land snails have globally (Bouchet 1992; Ponder 1997; Herbert 1998; been described and there may be 30,000 to 60,000 Killeen & Seddon 2004; Budha 2005; Solymos additional species yet to be described (Lydeard et & Feher 2005; Régnier et al. 2009). Killeen & al. 2004). Within modern India’s boundaries 1129 Seddon (2004) notably edited a volume with global species belonging to 140 genera and 26 families of coverage on molluscan biodiversity and conservation, land snails have been recorded (Ramakrishna et al. highlighting the importance of molluscan ecology 2010). The Western Ghats hotspot has 270 species of and conservation. However, very little information land snails of which 76% are endemic to this region is available on the status and threats of land snails (Aravind 2005) and 40% are micro-gastropods (i.e. in India. Here, we review current status of ecology, <5mm on greatest dimension) (Aravind et al. 2008). conservation and threats to land snails with particular Unlike most other systematic groups many land snail reference to India and discuss the strategies required species have restricted range distributions with some for conserving this important group. endangered species having a range of less than 5km2 and many endemic species having ranges less than Early studies on land snails in India 10km2 (Cameron 1998; Dunk et al. 2004). According Indian malacology was pioneered by William to Solem (1984) nearly half of all terrestrial molluscs Henry Benson (1803–1870), who contributed have a species range of less than 100km2. Within the significantly to our knowledge on Indian land snails Western Ghats, species distributed in the southern in the mid 19th century (Naggs 1997). The Blanford region are absent in the northern region. Further, there bothers-William and Henry, H. Theobald, L. Pfeiffer, is very little overlap between the southern and central, G.K. Gude, H.H. Godwin-Austen and R. Beddome, and central and northern regions (Table 1; Aravind led Indian land snail research until the early 20th 2005). Nearly 75% of land snails from the Western century, but Gude and Pfeiffer’s research was based Ghats have been reported from less than three sites entirely on museum material as neither visited India. (Fig. 1). This data clearly indicates how vulnerable this 3030 Journal of Threatened Taxa | www.threatenedtaxa.org | September 2012 | 4(11): 3029–3037 Land snaffs of Indfa S. Sen et af. Tabfe 1. Percent specfes shared between dffferent regfons 40 of the Western Ghats (Dfvfsfon of the Western Ghats fs 35 based on Aravfnd et af. 2005) 30 Regfon South Centraf North 25 South 100 20 E-17.19 Centraf 100 NE-11.11 15 Percent specfes Percent E-0.00 E-1.56 10 North 100 NE-2.78 NE-1.39 5 0 1 2 3 4 5 >5 Number of focatfons group fs to any smaff scafe change fn the ecosystem. Ffgure 1. Dfstrfbutfon pattern of fand snaffs fn the Western Ghats The sftuatfon fn other regfons of Indfa fs afso cause for concern. Northeastern Indfa harbours a rfch mfxture of Indfan and Burmese/Mafayan snaff groups resuftfng between forest patches (Aravfnd 2005; Raheem et af. fn the hfghest specfes dfversfty fn thfs regfon, but there 2008).