Page 20 - Special Issue
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 Figure 4: Relationship between acoustic parameters of the two note (co qui) advertisement call of male Puerto Rican coqui frogs and alti- tude at which the animals live, sampled in 1983-1984 (dashed lines) and again in 2006 (solid lines). Lines represent the best-fitting linear regression through the data for each time period. (A), the “co” note in the advertisement call decreases in frequency as altitude increases. (B), the “qui” note decreases in frequency as altitude increases. (C), total call duration (both notes together) increase as altitude increas- es. Regression lines for the two time periods are parallel, but shifted. Over the 23-year span, mean ambient temperatures increased by
Larval fish are thought to rely on sensory cues such as ol- fUacntliiokne aenctdotheearrminsg, efonrdoptrhederamtosr (abviordidsaanncde amnadmfomrallosc) arleizg- iunlgatreeebfosdeyttlteemepnetrasittuerse. bNyoisnyterreneafsl ipnhdyisciaotleotghiceapl rmeseanncse. oThf peredaarteofresw, sdoamtaotshtaltaardvadlrefisshthweilql uaevsotidonthoefsheonwoiascyosuitsetisc. Lcoarmvamlucnloicwantifiosnhirneaernedotinhewrmatseris waffitehcteldevbaytegdloCbOal2wleavrmels- dinidg.nThot aisvoisida pnaoristiycsuiltaersl;yinimstpeaodr,tathnet yqudesmtionsitnrastpedecnieospsruecfh- earsensocnegfboirrsdist,eswdheopsensdoincigalonandoirseplreovdeul c(Ftivgeurbee3h;aSvimorpssaorne elatragle.,l2y0r1e1g)u.lThateids sbuygvgoecstasl tchuaetso(cseoanng)a.ciAdisfiidceatfiroonmmtahyersemsualtl inflaubernecaekdoofwsnouonfdpraebdsaotorprtaivoonidoancseonamg obnangdfiwshidstphec(iSenseblly- dRiosroudp, t2in01g2t)h,eiitrisabniolitykntowdenteicf toathnedrloacoauliszteicsopuanradmsoetuercseos.f song, like those of frog advertisement calls, vary with tem- fpereatsurhewovaertgeerogsrapehicigerasdients.
havio avoid carbo from
spons ing te thres magn and w partic catio temp cies t to te of inc ened
effe Co Clim speci cipita clima ate o by al As di pacts impa perat et al., speci than 2012) habit these clima to ot anim
0.37° C.
Figure adapted from Narins and Meenderink (2014).
is below the resolution of Global Climate Models (GCMs),
1912 and 1990-1999, four of six frog species acoustically censused in the area around Ithaca, New York, began calling earlier in the spring, by10-13 days. This shift towards the earlier onset of advertisement calling was correlated with an average increase of 1-2.3° C in the springtime mean daily temperatures. What effect this earlier breeding has on pop- ulation size or viability is not known.
Changing environmental temperatures can also impact acoustic communication in tropical anurans. Narins and Meenderink (2014) compared advertisement calls of male Puerto Rican coqui recorded in 2006 to those recorded 23years earlier, in 1983-84. These frogs are found at differ- ent altitudes in their natural habitat, and the acoustic pa- rameters of their advertisement calls vary over this altitu- dinal gradient. At both time periods, the frequencies of the two notes in the advertisement call decreased with elevation (Figure 4), and the duration of the entire two note call in- creased with elevation, and at similar rates. That is, the best- fitting regression lines through the data from both time pe- riods are parallel, but are offset. Note frequencies are higher in 2006 but call duration is shorter. These shifts are mir- rored in an upward shift in mean local temperatures of 0.37° C (range 0.34-0.41° C) over this 23 year span. Although laboratory studies have shown that temperature affects the ability of some species of female frogs to discriminate adver-
20 | Acoustics Today | Spring 2020, Special Issue Reprinted from volume 10, issue 3
in these animals. In some songbird species, the brain nuclei
bioacoustic Monitoring Contributes
to an Understanding of Climate Change
oticseamnebnetccaaulslse l(oGgeirsthiacrsdhtaavnedprHevuebnetre, d20sc0i2e)n, titstis fnromt kancoiwdin-
fiyf itnhge thealrairngesveonlsuimtiveistyoof fsefeamwatlercnoeqcueissfraorygstohaosbsheriftvedein-
caremaasensnienr apbasroarllpetlionng. the shift in the male coqui’s call. Any
disconnect between the male’s vocal output and the female’s
In addition to the decrease in sound absorption, the reduc-
hearing sensitivity would have severe negative consequences
tion in ocean pH may affect oceanic animals in other ways.
for species reproduction and survival.
Predicting the impact of climate change on freshwater spe-
Increasing temperatures may affect acoustic communication
cies is more difficult. The size of many freshwater systems
in temperate zone songbirds indirectly, by advancing the
breeding season (Torti and Dunn, 2005). Seasonal variabili-
which constrains the accuracy of climate projections for
ty is an important component of the communication system
these environments (Hobday and Lough, 2011). Addition-
 ally, unlike the relatively homogenous oceans, freshwater
controlling song production and song perception are larger
systems are enclosed and habitat specific. Because climate
in the spring than in the fall (Tramontin and Brenowitz,
models predict droughts in some regions and heavier rainfall
2000). These volume changes have been linked to changes
in others, we cannot create a unifying prediction as to how
in day length and levels of circulating hormones. The poten-
climate change will impact freshwater species (Hobday and
tial contributing factors of temperature or of precipitation,
Lough, 2011). For example, streams associated with melt-
which also vary seasonally, on these volume changes have
ing glaciers may increase in flow and volume as the planet
not been explicitly examined. It is not known if seasonal
warms, whereas lakes and ponds in other regions may desic-
variations in the sizes of brain areas occur to the same ex-
cate as those environments experience droughts. Increased
tent in years where springtime comes earlier, due to global
temperatures can result in a decrease in aquatic mixing and
turnover, resulting in stratified regions with hypoxic condi-
tions and low pH. Acidification of freshwater systems is pre-
bioacoustic Monitoring
dicted, but it is not known if significant changes in sound ab-
In addition to understanding how climate change can im-
sorption will occur due to the small size of most freshwater
pact the acoustic behavior of species, we can use acoustic
systems. Clearly more data are needed.
techniques to monitor changes in the distribution and vi- Aabniliatdydoitfiospneacliefascitnordtiffoecroentsihdaebritinatsp.redFiocrtienxgamthpeleim, bpiardcts oanrecloimnsaitdeecrehdanagneinindifcraetsohrwsaptecriesnvfoirocnlimeanttescihsatnhgeeesffinecet ocof mambuiennityt-ebmaspeedrabtiurdrewoantcthiengauddaittaosreytsspysrtoevmid.eFeisxhtens saivre ehcitsotothriecraml sdathtatornegtuhleateditshtreiibrubtiodny atnemd pteimraitnugreobfybreehfaevr- eionrcse. tBoiredxtseprencailetsemopsetravtulrnee, rabthleertothcalinmbayteincthearnagle,phoyswi- oelvoegr,icaarlesleotcpaotiendtsi.nThthe wtroatpeircsteamnpdearraetunroetaatswwheilclhoabnseimrvaelds wasertehehiorutseemdpaeffreactetsctohuenhteraprainrtgs s(eŞneskiteirvciitoieğsluofetwaol.,sp20ec1i2e)s. oAfccoautsfitsichs, cthane cphroanvindeel kceatyfiisnhfo(rImctaltuiornusopnutnhcetsaetusps)ecaineds atnhde trhoepirichalacbaitafitsh: b(Pyimreeclorduins gpibctiruds)s. oThngrsesinhocldristiocfanl ehuarbailtartes-, species abundance and distribution can be monitored and 10 | Acoustics Today | Summer 2014 | 13
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