One step forward: contrasting the effects of Toe clipping and PIT tagging on frog survival and recapture probability.
Amphibians have been declining worldwide and the comprehension of the threats that they face could be improved by using mark-recapture models to estimate vital rates of natural populations. Recently, the consequences of marking amphibians have been under discussion and the effects of toe clipping on survival are debatable, although it is still the most common technique for individually identifying amphibians. The passive integrated transponder (PIT tag) is an alternative technique, but comparisons among marking techniques in free-ranging populations are still lacking. We compared these two marking techniques using mark-recapture models to estimate apparent survival and recapture probability of a neotropical population of the blacksmith tree frog, Hypsiboas faber. We tested the effects of marking technique and number of toe pads removed while controlling for sex. Survival was similar among groups, although slightly decreased from individuals with one toe pad removed, to individuals with two and three toe pads removed, and finally to PIT-tagged individuals. No sex differences were detected. Recapture probability slightly increased with the number of toe pads removed and was the lowest for PIT-tagged individuals. Sex was an important predictor for recapture probability, with males being nearly five times more likely to be recaptured. Potential negative effects of both techniques may include reduced locomotion and high stress levels. We recommend the use of covariates in models to better understand the effects of marking techniques on frogs. Accounting for the effect of the technique on the results should be considered, because most techniques may reduce survival. Based on our results, but also on logistical and cost issues associated with PIT tagging, we suggest the use of toe clipping with anurans like the blacksmith tree frog.
Programa de Pós-Graduação em Ecologia, Departamento de Biologia Animal, Instituto de Biologia, Universidade Estadual de Campinas CP 6109, Campinas, SP, cep 13083-970, Brazil.
Murilo
M
Guimarães
Programa de Pós-Graduação em Ecologia, Departamento de Biologia Animal, Instituto de Biologia, Universidade Estadual de Campinas CP 6109, Campinas, SP, cep 13083-970, Brazil ; Ecology, Evolution, and Behavior Graduate Program, Department of Integrative Biology, The University of Texas at Austin 1 University Station #C0930, Austin, Texas, 78712.
Décio T
DT
Corrêa
Programa de Pós-Graduação em Biologia Animal, Departamento de Zoologia e Botânica, Universidade Estadual Paulista São José do Rio Preto, SP, Cep 15054-000, Brazil.
Sérgio S
SS
Filho
Programa de Pós-Graduação em Biologia Animal, Departamento de Zoologia e Botânica, Universidade Estadual Paulista São José do Rio Preto, SP, Cep 15054-000, Brazil.
Thiago A L
TA
Oliveira
Fish, Wildlife and Conservation Biology Department, Colorado State University PO 80523, Fort Collins, Colorado.
Paul F
PF
Doherty
Departamento de Ciências Biológicas, Universidade Federal de São Paulo Diadema, SP, Cep 09972-270, Brazil.
Ricardo J
RJ
Sawaya
Amphibians; Hylidae; detection probability; mark–recapture; multimodel inference; return rate