Clues supporting photoperiod as the main determinant of seasonal variation in amphibian activity

Canavero, Andrés; Arim, Matı́as

doi:10.1080/00222930903377539

Cited by 50 publications

(39 citation statements)

References 23 publications

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“…In contrast, photoperiod is a less well-studied climatic factor relative to seasonal changes in anuran behavior (Bradshaw and Holzapfel 2007). There is evidence that amphibians in subtemperate wetlands could be tracking photoperiod (as previously reported for temperature and rainfall) to determine their seasonal variations in activity (Canavero and Arim 2009). In addition, there has recently been significant improvement in the number of ecological studies of amphibians in the Neotropics, though most of these studies are concentrated in forested or tropical open habitats.…”

Section: Introductionmentioning

confidence: 78%

“…Note that different species could respond differently to abiotic variables that influence reproductive activity (Hartel et al 2007;Wells 2007). In addition to climatic variables, these triggers include other environmental parameters, such as photoperiod (Both et al 2008;Canavero et al 2009), which can make the detection of a general pattern of answers to the climatic variables difficult. In an attempt to predict mathematically the activity patterns of an anuran community in subtemperate wetlands in Uruguay, Canavero et al (2008) observed that the annual pattern of calling activity is determined by a response to a set of seasonal variables or a variable that synthesizes the entire seasonal variation, such as photoperiod.…”

Section: Discussionmentioning

confidence: 99%

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Seasonality in anuran activity and calling season in a Brazilian subtemperate wetland

Ximenez

Tozetti

2015

Zool. Stud.

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Background: Most tropical regions have a climate characterized by marked seasonal rainfall patterns, and these seasonal patterns of rainfall directly affect anuran activity. However, in regions with temperate climates, the main aspect of climate related to anuran activity is the thermal regime. Thus, transitional climate regions represent good opportunities to study the effect of abiotic factors on anuran activity. In this study, we present new data on the activity pattern and calling season of Neotropical anurans in a subtemperate climate. Anuran activity was assessed based on the rate of capture of specimens in pitfall traps and calling surveys. The field study was conducted between May 2010 and April 2011 in wetlands in southernmost Brazil. Results: An analysis based on directional (circular) statistics showed that general activity in the studied anurans was significantly seasonal. In addition, the general activity pattern of most species was regulated by temperature, not by rainfall, and approached that observed in regions with a temperate climate. However, we did not record a well-defined peak in the number of species displaying calling activity. This parameter did not exhibit any influence of temperature variations or rainfall. Conclusions: The observed general activity pattern is different from that expected for the majority of anurans inhabiting eastern South America. The present study showed that the general activity patterns of most anurans in the wetland region in southernmost Brazil are regulated by temperature and not rainfall, similar to the pattern of anuran assemblies from temperate climates. However, the nonexistence of a significant relationship between calling activity and any of the environmental variables tested suggests the presence of a different environmental factor (e.g., photoperiod or the length of the hydroperiod of the relevant water bodies) as a trigger for the levels of general calling activity.

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Section: Introductionmentioning

confidence: 78%

Section: Discussionmentioning

confidence: 99%

Seasonality in anuran activity and calling season in a Brazilian subtemperate wetland

Ximenez

Tozetti

2015

Zool. Stud.

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“…; Narins & Meenderink ). In their examination of geographic structure of community seasonality in amphibians, Canavero and Arim (,) suggest that both latitude and diversity influence the nestedness and segregation of amphibians across time. Across regions, it is reported that anurans have longer reproductive periods in the wet tropics than those species occurring in tropical seasonal and temperate regions (Duellman & Trueb ).…”

Section: Introductionmentioning

confidence: 99%

Environmental drivers of anuran calling phenology in a seasonal Neotropical ecosystem

Schalk

Saenz

2015

Austral Ecology

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Temporal variation represents an important component in understanding the structure of ecological communities and species coexistence. We examined calling phenology of an assemblage of anurans in the Gran Chaco ecoregion of Bolivia by deploying automated recording devices to document nocturnally vocalizing amphibians nightly at seven ponds from 20 January 2011 until 31 October 2011. Using logistic regression, we modelled the relationships between temperature, rainfall and photoperiod with calling activity. There was a distinct seasonal effect with calling activity concentrated in the rainy season with no species detected during the dry season from June until the end of October. Calling activity was positively and significantly correlated with photoperiod in 9 of the 10 species analyzed, but there were distinct species-specific relationships associated with rainfall and temperature. All of these species utilize ephemeral ponds as breeding sites, which can account for their reliance on rainfall as an important driver in calling activity. Two prolonged breeders exhibited similar seasonal breeding patterns across the rainy season, but differed in their response to daily abiotic factors, which might be attributed to the constraints imposed by their reproductive mode. Explosive breeders needed several days of rain to elicit calling. Two pairs of congeners had distinct species-specific relationships between their calling activity and abiotic factors, even though the congeners shared the same reproductive mode, suggesting that the reproductive modes vary in the constraints imposed on calling activity. The patterns observed suggest that calling phenology of tropical anurans is determined by the interaction of exogenous factors (i.e. climatic variables) and endogenous factors (i.e. reproductive modes).

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“…Although photoperiod and the lunar cycle provide predictable cues that amphibians may use to synchronize their behaviour (Fitzgerald & Bider 1974;Both et al 2008;Canavero & Arim 2009;Grant et al 2009), the activity of many species is ultimately dictated by unpredictable climatic variables because of their permeable skin and ectothermic bodies (Duellman & Trueb 1994). Among these, precipitation tends to exert the greatest influence (Bulger et al 2003;Lemckert & Brassil 2003), but temperature (Howard 1978;Van Gelder et al 1986), humidity (Bellis 1965;Bartelt et al 2004), wind (Penman et al 2006;Philips et al 2007), light intensity/cloud cover (Jameson 1955;Blankenhorn 1972), and barometric pressure (Blankenhorn 1972) can also significantly affect amphibian activity.…”

mentioning

confidence: 99%

Spawning and non-breeding activity of adult giant bullfrogs (Pyxicephalus adspersus)

Yetman

Ferguson

2011

African Journal of Herpetology

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Abstract.-Populations of the Near-Threatened giant bullfrog (Pyxicephalus adspersus)have been poorly monitored due to the unpredictable appearance of this species aboveground. To better understand the activity of P. adspersus we quantified spawning by a population during five summers, and the activity of twenty adult frogs radio-tracked at the same site ca. twice weekly during the first three summers. In addition we examined animal activity, and population spawning in relation to meteorological variables, day of season, and moon light. During the six-month summer period, males and females, respectively, spent 10 ± 7 and 3 ± 2 days at water, and 22 ± 5 and 13 ± 5 nights active. Greater proportions of radio-tracked animals moved overland, and/or foraged at night, around full moon, after heavy rainfall, when cooler, and less windy conditions prevailed. More animals were found at water, or on land during the day, and population spawning was more likely, earlier in summer, following heavier rainfall. Spawning occurred most frequently, in descending order, during December, January, and November, and was triggered by 40 ± 16 mm rain in 24 h. Spawning events lasted 2 ± 1 days, but were prolonged around full moon.Numbers of males at spawning events varied between 30 and 500 males, and were positively correlated with the previous day's rainfall. Annually 6 ± 1 spawning events occurred, and numbers of annual spawning events were positively correlated with total summer rainfall. Results of this study show that single counts of spawning adults will often result in gross underestimates of population size, and therefore, long-term adult counts are necessary to detect real population trends. Due to the unpredictable activity of adults, however, it may be more practical to monitor, within certain areas, the number of aquatic sites where breeding occurs, for improved conservation management of P. adspersus. 3Although photoperiod and the lunar cycle provide predictable cues that amphibians may use to synchronize their behaviour (Fitzgerald & Bider 1974;Both et al. 2008;Canavero & Arim 2009;Grant et al. 2009), the activity of many species is ultimately dictated by unpredictable climatic variables because of their permeable skin and ectothermic bodies (Duellman & Trueb 1994). Among these, precipitation tends to exert the greatest influence (Bulger et al. 2003;Lemckert & Brassil 2003), but temperature (Howard 1978;Van Gelder et al. 1986), humidity (Bellis 1965;Bartelt et al. 2004), wind (Penman et al. 2006Philips et al. 2007), light intensity/cloud cover (Jameson 1955;Blankenhorn 1972), and barometric pressure (Blankenhorn 1972) can also significantly affect amphibian activity. Amphibians in dry and/or cold environments are most limited by suitable warm, wet conditions, making it difficult to predict their behaviour or even their presence (e.g., Bulger et al. 2003;Bartelt et al. 2004;Goldberg & Schwalbe 2004). This can represent a serious challenge for effective conservation management of threatened amphibian taxa (e.g., Penman et al...

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Clues supporting photoperiod as the main determinant of seasonal variation in amphibian activity

Cited by 50 publications

References 23 publications

Seasonality in anuran activity and calling season in a Brazilian subtemperate wetland

Seasonality in anuran activity and calling season in a Brazilian subtemperate wetland

Environmental drivers of anuran calling phenology in a seasonal Neotropical ecosystem

Spawning and non-breeding activity of adult giant bullfrogs (Pyxicephalus adspersus)

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