Clemmer, J. H.

Miller, E. Z.

Rettig, Jessica E.

Smith, Geoffrey R.

English

Denison University

Denison University Denison Digital Commons Denison Faculty Publications 2011 The Effects of Temperature and Salinity on Wood Frog (Lithobates sylvaticus) Tadpole Growth and Survival J. H. Clemmer E. Z. Miller Geoffrey R. Smith Jessica E. Rettig Follow this and additional works at: https://digitalcommons.denison.edu/facultypubs  Part of the Biology Commons Recommended Citation Clemmer, J. H., Miller, E. Z., Wolgamott, L., Smith, G. R., & Rettig, J. E. (2011). The Effects of Temperature and Salinity on Wood Frog (Lithobates sylvaticus) Tadpole Growth and Survival. Bulletin of the Maryland Herpetological Society, 47(1-4), 38-41. This Article is brought to you for free and open access by Denison Digital Commons. It has been accepted for inclusion in Denison Faculty Publications by an authorized administrator of Denison Digital Commons. Volume 47 Numbers 1-4 January-December 2011 The Effects of Temperature and Salinity on Wood Frog (Lithobates sylvaticus) Tadpole Growth and Survival Abstract l11creased levels of road salt rt1noff in co1nbination with increasecl temperatures earlier in the spring co11ld create stressful e11vironments for wood frog (Lithobates s_)1[-\1atici1,s) tadpoles. We exa1nined the effects of salinjty and temperature as stressors, both indepe11dently and jointly. We t1sed tl1ree conce11trations of NaCl ( co11trol, low, and hjg]1) ar1d two temperat11re treat111ents. Higher ternperature rest1lted in significa11tly decreased s11rvivorship, but did not affect 111ea1  tadpole mass. Sal inity dicl not have a1y significant e·ffects, nor did tl1e i11teractio11 of sali11ity a11d temperature. These rest11ts suggest wa1111ing tre11ds 1nay have greater effects on this populatio11 tl1a11 cl1a1 ges in salinity. It is commo11 for northern te1nperate regions to have salt-contaminated freshwater habitats due to the freqt1ent t1se of road deicing compounds (e.g., Kat1shal et al., 2005). Such salt-contami-11ation ca11 caLtse stL1nted gro\vth, slo\ver rates of 1neta1norphosis, and decreased survival of anur,1n larvae (Dot1gherty ancl Smitl1, 2006; Collins and Rt1sselI, 2009; La11ghans et al., 2009), however some species or pop11latio11s of an11ra11s are relatively tolera11t of salt-contamination (e .g., Dougherty a11d Smith, 2006; Karraker, 2007; Colli11s a11d Russel], 2009). I11deed, some species appear to be pre,1ented fro1n occt1pyi11g ponds co11tan1inated with road salt, ,vhereas other species appear to be able to occt1py them (Colli11s and R11ssel l, 2009). Temperature is another factor tl1at can affect the performance of a11L1ran larvae. However, the effects of ten1peratt1re on anuran tadpoles can be variable, \Vith i11creased te1nperatt1res sho\vn ,, to clecrease taclpole gro\vtl1 in s01ne species (e.g. , Al\1arez and Nicieza, 2002; Orizaola a11cl LaL1ri]a, 2009) and increase tadpole growth i11 other species (e.g. , Sanuy et al., 2008; Castano et al ., 2010). Temperature ca11 also affect survivorship i11 tc1dpoles, ½1 ith l1igher temperattires sometimes rest1lting in lov\1er st1rvivorsl1ip ( e.g., Casta110 et al .. 2010) or 11.igher survivorship ( e.g., SanLty et al., 2008; Orizaola and Laurila , 2009). Wood frogs (Lithobates SJ1lvaticLt,c;) are a common and vvidespread frog in northeaster11 North America that inhabit vernal pools (Redmer a11d Trat1th, 2005). This is a regio1  where sali -nization of f'reshw,1ter is importa11t (Kat1shal et al ., 2005). Give11 that wood frogs are early spring breeders (Redmer and T·rau th , 2005), they are likely to be affected by both road salt contami11ation at1d a11y wa1·1ning trends associated vvith global cli1nate cl1a11ge. Previous st11dies have fotind that wood frogs are susceptible to tl1e effects ot· salt-co11tami11atio11, bt1t the conce11trations tl1at increase mortality or aft·ect gro'vvtl1 ca1  vary amo11g populatio11s (e.g., Colli ns and R11ssell, 2009; La11gha11s et al ., 2009; Petranka and Doyle, 2010). Road salt can also l1ave significant den1ographic effects on wood frog populatio11s (Karraker et al., 2008). Considering tem1)eratt1re. Castano et al. (2010) fot1nd that the st1rvivorship of wood frog tadpoles from Ohio was better at l 7°C tl1an at 25°C; however, tl1ey f'ot111d that taclpoles at 25°C vvere larger tl1an taclpoles at l 7°C. To our k11owledge, no previot1s study has examined the potential i11teraction bet\veen salt contaminatio11 and te1nperature 01  the perfor1nance of wood frog tadpoles. Such i11fo1mc1tion Lnay al-lo\v us to better Ltnderstand the pote11tial impacts of these e1viron1ne11tal stressors on wood frogs. page 38 Bulletin of the Maryland Herpetological Society Volume 47 Numbers 1-4 January-December 2011 To this end , we examined how tl1e combination of increased salinity a11d i11creased water temperature may affect the growth a11d survivorship of wood frog tadpoles . Materials and Methods We collected wood frog egg masses (N = 6) from a local pond ,vitl1in 24 h of oviposition. We inc11bated the eggs in the laboratory until hatching. Upo1  hatcl1ing, tadpoles \,Vere maintained i11 large plastic containers where tadpoles fro1n the diff'ere11t clutches ,,vere allo\ved to mix. We began the experi1nent once tadpoles reached Gosner Stage 26 (Gos11er, 1960) and had a n1ea11 mass of 0.023 + 0.001 g (N = 10). . The experiment was a 3 x 2 fully factorial design with tl1ree salinity treatments (control , low, and ]1igh) and t,vo temperattire treatments (25°C a11d 30.5°C) replicated 6 ti1nes. For the saLi11-ity treat1nents, we created stock solutions of the ]ow (500 mg NaC]/L) and higl1 (I 000 mg NaCl/L) salinity treatments t1sing NaCl (Fisher Scientific Sodium Chloride Certified for Biological Work) and aged ta1Jwater. Temperature treatments were created by placi11g t]1e containers in eitl1er a ther-mostat co11trolled lab (25°C) or a thennostat controlled greenho11se (30.5°C). Each experi11e11tal 1111 it consisted of a clear plastic container (21 c1n x 14 cm x 5 cm) fi ll ed with 500 mL of tl1e appropriate salinity solution. Each container had 5 tadpoles. Every 3 days ,ve refilled each container with water of the a1Jpropriate salt con.centration that had been accli1nated to the treatment ten1perature. We also re1noved feces and any rem,1ini11g food. We fed the tadpoles 0.05g of crusl1ed Purina Rabbit Chow per tadpole every 3 days. After 10 days, we recorded the n11mber of tadpoles alive in each container and weighed the st1rvivors to the nearest 0.001 g after blotting dry. We used two-way ANOVAs to analyze the effects of temperature a11d salinity 011 tadpole n1ass ai1d s11rvjvorship separately. Results SL1rvivorship to the end of the experiment was higl1er in the 25 °C treat1ne1ts than i1  the 30.5°C treatments (25°C: 0.80 ± 0.063 IN= 181, 30.5°C: 0.267 ± 0.096 IN= 18]; F1,3o = 22.26, P < 0.0001). Salinity had no effect on tadpole survivorship (Control: 0.65 ± 0.14 [N = 121, Lo"v: 0.47 + 0.1 2 lN = l 2J, High: 0.48 ± O.l l [N = 12]~ F2 ,3o = l .49, P = 0.24). The interactio11 betwee.n temperat1Lre and salinity vvas not significa11t (F2,3o = 1.18, P = 0.32). Meai1 tadpole mass was not significantly affected by te1nperature treatment (25°C: 0.0530 + 0.0037 g [N = 171, 30 .5°C: 0.0614 ± 0.0085 g [N = 61; F1.17 = 1.05, P = 0.32). Mean tadJJole 1nass was also not aft·ected by sal i11ity treatme11t (Control: 0.052 + 0.0009 g [N = 8], Low: 0.053 + 0.006 g LN = 7], High: 0.060 ± 0.009 LN = 8]; F 2,17 = 0.98 , P = 0.40). Tl1e i11teractio11 term 'A1as 1101 significant (F2,17 = 0.50, P = 0.61). Discussion Ot1r results indicate that NaCl concentrations of 500 and 1000 mg L-1 did not affect the growth or s11rvivorship of wood frog tadpoles. This is in contrast to other stttdies that have fottnd sali11 ity to negatively affect survivorship , growth, and size at metamorphosis in wood frogs at co11-centrations ranging 11p to 1400 mg L-1 (Sa1zo and Hecnar, 2006; Karraker et al ., 2008). However, Petra11ka a11d Doyle (2010) fou11d i11creased mortality in wood frog tadJJ01es only at co11centra-tio11s of 4500 1ng L-1 and no effect at lower conce11tratio11s. Thus, t11ere appears to be a ra1ge of susceptibi lity to salinity i11 wood frog tadpoles across their geographical range. Wl1at clrives s11ch variability in st1sceptibility is unknown but warrants further investigation. Bulletin of the Maryland Herpetological Society page 39 Volume 47 Numbers 1-4 January-December 2011 The surv ivorsl1ip of \VOod ·frog tadpoles at 25°C was greater than. their sLtrvivorship at 30 .5°C, bLtt 11ean tadpole 111ass did not differ betwee11 the temperatt1res. Castano et al. (2010) fot1nd that sL1rvivorship of \Vood frog tadpoles was better at l 7°C tha11 at 25°C; ho,vever, they fo11nd that tadpoles at 25°C \.Vere larger tha11 tadpoles at 17°C. Our res11lts for SLtrvivorship are ge11erally co1 sistent v,1ith Casta10 et al. (20 l 0) i11 that st1rvivors]1ip is better at tl1e cooler temperature. Our resl1lts are also co11sistent with the observation that 25°C is near the maximum tolerated temperature for wood frog tadpoles fro1n Ol1io (Manis a11d ClaL1ssen, 1985). Thus, l1igher te1nperatures a1)1)ear to negatively affect st1rvivorship i11 \.vood frog tadpoles. However, ot1r res11lts for mass and tl1ose fro111 Castano et al . (20 l 0) suggest that gro,vtl1 in woocl frog tadpoles in this Ol1io 1Jop11lation is ge11erall y better at l1igher temperatures since growth at 25°C was greater tha11 at l7°C (Casta110 et al., 2010) and si1nilar to that at 30 .5°C (this study). Tl1e res Lilts of these two experiments do SL1ggest tl1at i11creasi11g temperatures associated \ivith a warmi11g climate could have serious co11seque11ces for wood frogs , especially since the ir1creases in growth l)erformance appear to level off after 25°C. However, s1)ring te1nperatL1res t·or this Ohio 1Jopulatio11 would have to drastic,1lly increase to have substantial impacts on wood frogs ( water temperatt1res for t]1e source pond in th.is experin1e11t aver-aged 13 .7°C i11 early April; Dot1gherty et al., 2005). In s111n111ary, \Ve fou11d that wood frogs are 11ot strot1gly affected by NaCl concentrations of 500 a11d l 000 mg/I, bt1t tl1ey do suffer a redt1ction in survivorshit) when ex1)osed to a war1ner temperatLLre <.1f 30.5°C in comparison to 25°C. There does 11ot ho,vever appear to be a sy11ergistic effect of these stressors on vvood frogs in this population, as evidenced by the lack of a significant interaction between temperature and salinity. Acknowledgments We thank W. and L. S1nith for assista1ce collecting egg n1asses. The experiment was a1)proved by the Denison U11iversity IACUC (1Jrotocol 10-003). Literatu1·e Cited ., Alvarez, D. , a11d A.G. Nicieza, 2002. Effects of te1nperature and foocl quality on an11ran larval growt]1 a11d meta-n1orphosis. Fttnct. Ecol. 16: 640-648 . Castano, B .. S. Miely, G.R. Smitl1, and J.E. Rettig. 2010. I11teractive effects of ·food availal,ility a11d te1nperature on wood t·rog (Rana .sy/\1cltic'(1) tadpoles. 1-lerpetol. J. 20: 209-211. Col]i11s, S., ancl R. Russell . 2009. 1~oxicity of road salt to Nova Scotia amphibians. E11viron. Poll. 157: 320-324. Dot1gherty, C.K., and G.R. Smith. 2006. Act1te effects of road de-icers on the tadpoles of t11ree an11rans. Appl. Herpetol. 3: 87-93. Dot1gherty, C.K., D.A . Vaala, and G.R. Smith. 2005 . Within-pond oviposition site selection in tvvo spring breeding amphil,ians (Anl-b_vsto,,ia maci1Latun1, and Rana .'>_vlvatica). J. Fresl1water Ecol. 20: 781-782. Gosner, K.L. l960. page 40 A sin1plified table for stagi11g anuran embryos and larvae, \.Vith notes 011 ide11ti-f1.cation. Herpetologica 16: 183-190. Bulletin of the Maryland Herpetological Society Volume 47 Numbers 1-4 January-December 2011 Karraker, N .E. 2007. Are embryo11ic a11cl larval gree1  frogs (Rar1,a cLaniitans) insensitive to road deicing salt? Herpetol . Conserv. Biol. 2: 35-41. Karraker, N., J. Gibbs, a11d J. Vonesh. 2008. Impacts of road deici11g salt on tl1e demograp]1y of vernal pool-breedi11g amphibia1s. Ecol. Appl. 18: 724-734. Kaushal, S.S. , P.M. Groffman, G.E. Likens, K .T. Belt, W.P. Stach, V.R . Kelly, L .E. Ba1 d, and G.T. Fisher. 2005. I11creased salinization of freshwater i11 tl1e northeaster11 United States. Proc. Nat. Acad. Sci . 102: 13517- 13520. Langhans, M. , B. Peterso11 ,A. Walker, G.R . Sn1ith, and J.E. Rettig. 2009. Effects of saljnity on survivorship of \.vood frog (Rana S)1/vatica) tadpoles. J. Freshwater Ecol. 24: 335-337. Manis, M.L. , and D .L. Clausse1. 1986. Environ11e1tal and genetic influences on the thermal physiology of Rana sylvatica. J . Therm. Biol. 11 : 31-36. Orizaola, G., a11d A. Lat1rila. 2009. Microgeographic variatio1  in temperature-i11cluced plasticity i11 an isolated amphibjan metapopt1lation. Evol. Ecol. 23: 979-991 . Petranka, J.W., and E.J . Doyle. 2010. Effects of road salts on the composition of seaso11al po11d com1n t1nities: ca11 the use of road salts e11hance mosqu ito recruit1nent. Aquat. Ecol. 44: l 55-166. Redmer, M ., and S .E. Trauth. 2005. Rana sylvatica LeConte , 1825. !1: Amphibian Decl i11es: Tl1e Conservatio11 Statt1s of United States Species, p. 590-595. La111100, M. Ed., University of California Press, Berkeley. Sanuy, D., N. Oromi, a11d A. Galofre. 2008. Effects of te1nperature on embryo1 ic a11d larval development a11d gro'vvth in the natte1jack toad (B11/0 calamita) in a semi-arid zone. An i111. Biodiv. Co1serv. 31 : 41-46. Sanzo, D. , and S. Hecnar. 2006. Effects of road de-icing salt (NaCl) on larval wood frogs (Rana s_ylvatic·a) . Enviro1 . Po11. 140: 247-256 Jen,n,ifer H. Cleni,ner, Eliza Z. Miller, Laura Wolgamott, Geoffrey R. S1nitJ1,~i<, and Jes5;ica E. Rettig Department o_f Biology, De1iiso1i University. Granville, OH 43023 USA *Author for Corres;Jonde1ice: Plion.e: l -740-587-6374, e-mciil smitlig@der1iso11 .edit Received: Accepted: 12 October 2011 1 November 201 1 Bulletin of the Maryland Herpetological Society page 41 

The Effects of Temperature and Salinity on Wood Frog (Lithobates sylvaticus) Tadpole Growth and Survival

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The Effects of Temperature and Salinity on Wood Frog (Lithobates sylvaticus) Tadpole Growth and Survival

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