A Comparison of Hill Stream Anuran Diversity Across Two

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frog leg | #15 | February 2011 A comparison of hill stream anuran diversity diversity and abundance have across two habitats in Kalakad-Mundanthurai been found to vary under the influence of varied factors such Tiger Reserve: a pilot study as differences in litter fall rates, mast fruiting, heterogeneity Chetana B. Purushotham 1, Kaushalika Dharmadhikari 2 & within regions, breeding habitat Ramachandran Vivek 3 constraints, and geological 1 Agumbe Rainforest Research Station, Suralihalla, Agumbe, Thirtha- history (Allmon 1991) and also halli Taluk, Shivamogga District, Karnataka 577411, India due to altitude, topography, 2 Sudakshina C, LIC Colony, Paud Road, Pune, Maharashtra 411038, and rainfall (Duellman 1999). India Given that factors relating to 3 Ashoka Trust for Research in Ecology and the Environment (ATREE) environmental and habitat Royal Enclave, Srirampura, Jakkur Post, Bengaluru, Karnataka 560064, variation; both at a micro and India macro level can influence the Email: 1 [email protected] nature of anuran assemblages, our study aims at investigating India, one of the most 2002). While much focus still the diversity and composition populous countries, with lies on bringing about clarity of anuran assemblages in hill an estimated population in the taxonomic aspects of streams within and across of 1.1 billion, also has the this class of vertebrates, there habitats in one mountain range greatest amphibian species exists a dearth of research of the southern Western Ghats. richness (321), endemics centred around their ecology, Questions that we put forth: (i) (180) and threatened species behaviour, species assemblages How do anuran assemblages of all countries in the Indo- and for some species, natural vary across hill streams in two Malayan realm (Bain et al. history. habitats with respect to species 2005). According to the In the neotropics, species richness and diversity (ii) What Global Amphibian Assessment (GAA) almost one-third of the worlds 6,638 known amphibian species are listed as threatened or extinct. These declines are attributed to two major factors, habitat loss and fungal disease with possible contributions from introduced species, climate change and pollution (Beirne 2009). In the Western Ghats, one of the 34 global biodiversity hotspots (Mittermeier et al. 2005), endemic anurans are also at risk due to their specialised diet, habitat preferences and © Sandeep Das limited vagility (Gururaja Image 1. Tea plantation stream

2 frog leg | #15 | February 2011 ambient temperature 240C). Field Survey: We surveyed for stream anurans towards the tail end of the south west monsoon in the month of August, 2010 over a period of three consecutive days. Time constrained surveys were carried out using the line transect method (Parris et al. 1999). Two 450m long transects were selected, one in each habitat type. Two observers on either side of each © Sandeep Das stream transect for 2hr twice Image 2. Primary forest stream a day. This resulted in a total of 48 man hours of sampling. At every detection spatial factors are likely to influence primary evergreen forest of variables (orientation of an variations in these hill stream the Cullinia, Aglaia, Palaquium individual from the surface of anuran assemblages within and type (Ganesh et al. 1996), with the water) and substrate (ferns, across the two habitats? an average canopy height of grass, green leaves, dead Methods: This study was 30m with dense canopy cover leaves, dead leaf packs, fallen conducted in Kakachi, within (mean ambient temperature logs, mossy rocks, crevices, the Kalakad-Mundanthurai 220C). The stream had an rocks) were recorded. Species Tiger Reserve (KMTR) spread average width of 5m and were identified using field keys over 895km2 located in the was characterized by a sandy by Daniel (2002), Dinesh et Agasthyamalai ranges of Tamil stream bed embedded with al. (2008); nomenclature after Nadu. It is one of the most large boulders and rocks. Dinesh et al. (2010). diverse among the protected Presence of fallen logs and Data Analysis & Results: areas in southern Western rapids were also a regular Analysis of all the data collected Ghats (Ganesh et al. 2009). A feature of the stream. was done using Microsoft Excel total of eight species of stream Tea plantation stream (Image (Office 2007) and the statistical anurans are known to exist 2): This stream had an average analysis software – PAST 2.00 in the Agasthyamalai range width of 3m and ran alongside (Hammer 2010). (Vasudevan et al. 2004). a road with tea plantations Species richness and The two habitats chosen bordering it on either side. diversity across habitats: for the study were at a similar The vegetation adjoining the During 24hr of observation, elevation of around 1200m but stream was composed of tall a total of seven species were differed in other aspects such as grasses and reeds on one side recorded in both the streams vegetation, canopy cover, and and overhanging Ochlandra with a total of 160 individuals average ambient temperature. travancorica thickets on the (Table 1). One-hundred-and- Forest stream (Image 1): other side for nearly 70% of twelve individuals belonging The stream was located in a the stretch sampled (mean to four genera (Micrixalus,

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Image 3. Hylarana temporalis

Table 1. Checklist of anurans encountered during the survey

IUCN Status Bufonidae Duttaphrynus melanostictus LC Micrixalidae Micrixalus saxicola VU Micrixalus fuscus NT Nyctibatrachidae Nyctibatrachus aliciae EN Nyctibatrachus vasanthi EN Ranidae Hylarana temporalis NT Ranixalidae Indirana beddomii LC Image 4. Goolge Earth image of the primary forest stream

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7 40 Forest stream 35 Rocky water pools Rapids Still waters Fern Islands 6 Tea plantation 30

5 25

20 4 15 Occurrences 3 10 No. of species 5 2 0 Micrixalus Nyctibatrachus Hylarana Indirana 1 Figure 2. Habitat use across genera in the forest stream 0

50 150 250 350 450 550 650 750 850 950 1050 11501250135014501550165017501850 Distance (m) to the rest of the substrate Figure 1. Species accumulation curve for the forest stream types available, namely fallen and tea plantation with sampling effort (distance sampled). logs, soil, ferns , rocks etc. Box plots were drawn to Nyctibatrachus, Hylarana and the two habitats for species depict distance from the edge Indirana) were recorded from richness showed that the forest of water and vertical height the forest stream while only stream not only had a higher above the surface of water 48 individuals belonging to species richness and diversity for individuals of each genus. two genera (Hylarana and as compared to the tea Most of the individuals were Duttaphrynus) were recorded plantation but also had a more found to occur within 1m from from the tea plantation stream. evenly distributed community the edge of the water with a Only one of the seven species, structure (Table 2). few exceptions of individuals Hylarana temporalis (Image 3) Anuran assemblages: (a) of Hylarana and Micrixalus was found to be common to Forest stream (Image 4): occurring further inland. While both the habitats. Anuran assemblages were individuals of Nyctibatrachus The species accumulation quantitatively assessed in were found either submerged curve for sampling effort terms of habitat use by or at water level, Micrixalus (Fig. 1) has not reached an grouping them under broad and Hylarana were found at asymptote for the forest habitat classes namely fern varied heights up to 1.5m from stream as opposed to a distinct islands, still waters, rapids the surface of water (Figs. 3a plateau for the plantation and rocky water pools (Fig. 2). & 3b). stream after encountering just Although Micrixalus (Image 5) (b) Tea plantation stream two species. The absence of a was found to occur in all the (Image 7): Only two genera distinct asymptote in the forest habitat classes, it was most Duttaphrynus, Hylarana stream suggests sampling was seen in rapids. Nyctibatrachus were found in this habitat inadequate for this habitat. (Image 6) on the other hand of which only one individual Jaccard’s Index was used was found to occur more in still of Duttaphrynus was found. to test for similarity in the waters and fern islands. Among the 47 individuals of two streams showed that the Further, a comparison Hylarana 44% of them used sites were 42% similar based between the four genera in grass and 35% used soil as on substrate availability (Cj = the forest stream showed that their substrates over others. 0.428571). rocks and dead leaf litter were Effect of disturbance in the Indices used to compare used most often as compared Tea plantation: High levels of

5 frog leg | #15 | February 2011 3 22 2.72.7 1.81.8 2.42.4 1.61.6 2.12.1 1.41.4 1.81.8 1.21.2 1.51.5 11 1.21.2 0.80.8

Distance from water (m) 0.6 Distance from water (m) 0.90.9 0.6 0.60.6 0.40.4 Distance from Water(m) 0.2 0.30.3 Distance Above Water (m) 0.2 0 0 0 Micrixalus Indirana Hylarana Nyctibatrachus 0 Micrixalus Indirana Hylarana Nyctibatrachus Figure 3a. A box plot showing the distance of individuals of Figure 3b. A box plot showing the assemblage of individuals each genus from the edge of the water of each genus with respect to vertical distance above the

surface of the water. Micrixal Micrixal Inndiran Nyctibat Indirana Hayalara Nyctibat Hyalaran

Table 2. Diversity Indices showing a significant difference between the two habitat types.

Tea plan- Forest Indices tation stream stream

Species richness 6 2 Individuals 112 48 Shannon_H 1.423 0.1013 Simpson_1-D 0.7132 0.0408 Evenness_e^H/S 0.6913 0.5533

Discussion: Of the two habitats studied, the stream © Sandeep Das running through the primary Image 5. Micrixalus fuscus forest had a higher species richness, species abundance human activity like washing species abundance. It showed and evenness, resulting clothes, vehicles & livestock a high correlation between in higher species diversity and letting in grey water from species abundance and their (Table 2). In this study we neighbouring households in and distance from the source of hypothesised there to be a around the start point of the disturbance (y = ax+b where difference in the diversity transect had been qualitatively slope a = 0.056921; intercept between the tea plantation (TP) considered as a source of b = -8.8969 ; r2 = 0.075754 ), and forested area (FP) however disturbance. A linear model the p value (0.4735) however one this drastic is surprising. was used to see the influence was not significant. Another study done in of these disturbances on KMTR showed the amphibian

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Image 6. Nyctibatrachus cf. aliciae

assemblages in evergreen streams to be considerably different between two hills, separated by <2 latitude in the same mountain range (Vasudevan et al. 2004). Our study however shows a considerable difference between assemblages in two streams in the same latitudinal area with varying land use. It is interesting to note that individuals of Hylarana and Duttaphrynus encountered in the tea plantation area were Image 7. Goolge Earth image of the tea plantation stream not fully grown adults as in a similar study done on stream

7 frog leg | #15 | February 2011 amphibians which showed litter, ferns, moss, boulders Reserve Amphibian and Benthic that juveniles of these species etc) were present in the forest Surveys. Amazon Phase Report remain along the stream stream while only 38% (grass, 092. only for a brief period. They rocks, soil, etc.) were present Daniel, J.C. (2002). Bombay Natural History Society and eventually disperse into the in the tea plantation stream. A Oxford University Press, forests, which are their feeding clear indication that land-use Mumbai, The book of Indian grounds, and adults therefore, change has not only affected Reptiles and Amphibians. are rarely found along the the vegetation but also changed i-viii+238pp. streams (Krishna et al. 2005) the stream characteristics. Dinesh, K.P., C. Radhakrishnan had we conducted the survey The short duration and & G. Bhatta (2008). A new one or two months earlier or scale at which the study was species of Nyctibatrachus after the time period chosen, carried out can be considered Boulenger (Amphibia: Anura: even these individuals may as its short-coming. However, Nyctibatrachidae) from the surroundings of Bhadra Wildlife not have been found in the observations from our study Sanctuary, Western Ghats, plantation. Fluctuations in give us reason to look at India.Zootaxa 1914: 45–56. pH as well as other physical conservation and management Dinesh, K.P., C. Radhakrishnan, parameters of the water have of lotic water systems not just K.V. Gururaja, K. Deuti & G. known to influence the biology at a regional scale but at a Bhatta (2010). A checklist of amphibians (Warner et al. more local one as well. of Amphibia of India. http:// 1998). In this case however zsi.gov.in/checklist/Amphibia_ we can consider fluctuations References final.pdf. Accessed on 23 arising as a result of the human August 2010. Allmon W.D. (1991). A plot Duellman, W.E. (1988). Patterns induced disturbance only a study of forest floor litter frogs, of species diversity in anuran possible explanation for the Central Amazon, Brazil. Journal amphibians in the American poor diversity in the stream as of Tropical Ecology 7: 503– tropics. Ann. Missouri Bot. they were not quantified in the 522. Garden 75: 79–104 study. Bain, R., S.D. Biju, R. Brown, I. Ganesh, T., R. Ganesan, M.S. Another possible factor Das, A. Diesmos, S. Dutta, D. Devy & J. Pai (2009). to explain the difference in Gower, R. Inger, D. Iskander, Treasures on Tiger Tracks Y. Kaneko, M.W.N. Lau, M. species diversity could be the - A Bilingual Nature Guide Meegaskumbera, A. Ohler, T. substrate availability along to Kalakad-Mundanthurai Papenfuss, R. Pethiyagoda, Tiger Reserve. Ashoka Trust the streams. Modifications in B. Stuart, M. Wilkinson & for Research in Ecology and the microhabitat have known M. Xie (2005). Amphibians of Environment (ATREE). adverse effects on amphibians the Indomalayan Realm, 74 – Ganesh, T., R. Ganesan, M.S. (Gururaja 2002). Changes 84.In: Stuart, S.N., Hoffmann, Devy, P. Davidar & K.S. Bawa in substrate availability could M., Chanson, J.S., Cox, N.A., (1996). Assessment of Plant compromise on the availability Berridge, R, Ramani, P. and Biodviersity at mid-elevation of shelter, prey and egg Young B.E. eds. Threatened evergreen forest of Kalad Amphibians of the World. Lynx laying sites. In this study Mundanthurai Tiger Reserve, Ediciones, with IUCN - The we qualitatively assessed the Western Ghats, India. Current World Conservation Union, Science 71(5): 379-392. variety of substrates used by Conservation International, and Gururaja, K.V. (2002). Effect the anurans at a microhabitat Nature Serve, Barcelona. of Habitat Fragmentation on level. Of the 13 substrates that Beirne, C., J. Escolar & A. Distribution and Ecology of we identified 77% of them (leaf Whitworth (2009) Yachana Anurans in Some Parts of

8 frog leg | #15 | February 2011 Central Western Ghats. PhD (2005). Hotspots Revisited: Warner, S.C. & W.A. Dunson Thesis submitted to Kuvempu Earth’s Biologically Richest and (1998). The effect of low University, Shankaraghatta, Most Threatened Terrestrial pH on amphibians breeding 33-38pp. Ecoregions, Conservation in temporary ponds in North Hammer, Q., D.A.T. Harper, International. Florida. Fla. Game and Fresh & P.D. Ryan (2001). PAST: Parris, K.M. & M.A. McCarthy Water Fish Comm. Tallahassee Paleontological Statistics (1999). What influences the Report number GFC86-033: software package for structure of frog assemblages 88. education and data analysis. at forest streams? Centre for Palaeontologia Electronica Resource and Environmental Acknowledgment 4(1): 9. Studies, The Australian National We would like to thank Jamsetji Krishna, S.N., S.B. Krishna & University, Canberra ACT 0200, Tata Trust and ATREE for funding K.K. Vijayalaxmi (2005). Australia. Australian Journal of and logistic support Tamil Nadu Variation in anuran abundance Ecology 24: 495–502 Forest Department and Tamil Nadu along the streams of the Vasudevan, K., A. Kumar & Electricity Board for permissions Western Ghats, India. Journal R. Chellam (2004). Species and logistics. RV was supported of Herpetology 15: 167–172. turnover: the case of stream through a fellowship by NORAGRIC Mittermeier, R.A., P.R. Gil, amphibians of rainforests in the (UMB). We would also like to thank M. Hoffman, J. Pilgrim, T. Western Ghats, southern India. the reviewers of JoTT for their con- Brooks, C.G. Mittermeier, J. Biodiversity and Conservation structive feedback. Lamoreux, & G.A.B. Fonseca 15: 3515–3525

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