Marine iguanas shrink to survive El Niño

Wikelski, Martin; Thom, Corinna

doi:10.1038/47396

Cited by 180 publications

(137 citation statements)

References 9 publications

Supporting

Mentioning

127

Contrasting

Unclassified

Order By: Relevance

“…At broad spatial scales, overall patterns and degree of size change in our study are similar to those found for several other terrestrial ectotherms examined so far (McCarthy, Masson, Thieme, Leimgruber, & Gratwicke, 2017; Tryjanowski, Sparks, Rybacki, & Berger, 2006; Wikelski & Thom, 2000). Two species of European frogs, for example, increased in size from 1963 to 2003 (Tryjanowski et al., 2006) in conjunction with milder winters, and the authors suggest that warmer winters may have increased the number of insect prey, resulting in higher growth rates of these species.…”

Section: Discussionsupporting

confidence: 87%

Shifts in frog size and phenology: Testing predictions of climate change on a widespread anuran using data from prior to rapid climate warming

Sheridan

Caruso

Apodaca³

et al. 2017

Ecology and Evolution

View full text Add to dashboard Cite

Changes in body size and breeding phenology have been identified as two major ecological consequences of climate change, yet it remains unclear whether climate acts directly or indirectly on these variables. To better understand the relationship between climate and ecological changes, it is necessary to determine environmental predictors of both size and phenology using data from prior to the onset of rapid climate warming, and then to examine spatially explicit changes in climate, size, and phenology, not just general spatial and temporal trends. We used 100 years of natural history collection data for the wood frog, Lithobates sylvaticus with a range >9 million km2, and spatially explicit environmental data to determine the best predictors of size and phenology prior to rapid climate warming (1901–1960). We then tested how closely size and phenology changes predicted by those environmental variables reflected actual changes from 1961 to 2000. Size, phenology, and climate all changed as expected (smaller, earlier, and warmer, respectively) at broad spatial scales across the entire study range. However, while spatially explicit changes in climate variables accurately predicted changes in phenology, they did not accurately predict size changes during recent climate change (1961–2000), contrary to expectations from numerous recent studies. Our results suggest that changes in climate are directly linked to observed phenological shifts. However, the mechanisms driving observed body size changes are yet to be determined, given the less straightforward relationship between size and climate factors examined in this study. We recommend that caution be used in “space‐for‐time” studies where measures of a species’ traits at lower latitudes or elevations are considered representative of those under future projected climate conditions. Future studies should aim to determine mechanisms driving trends in phenology and body size, as well as the impact of climate on population density, which may influence body size.

show abstract

Section: Discussionsupporting

confidence: 87%

Shifts in frog size and phenology: Testing predictions of climate change on a widespread anuran using data from prior to rapid climate warming

Sheridan

Caruso

Apodaca³

et al. 2017

Ecology and Evolution

View full text Add to dashboard Cite

show abstract

“…Adults and juveniles may experience no growth or shrinking during drought, yet in productive seasons juveniles may rapidly approach the size of more slowly growing older tortoises. Decrease in carapace length during drought was noted for two juvenile tortoises in another study (Berry et al, 2002) and shrinking has been measured in marine iguanas in times without food (Wikelski and Thom, 2000). Carapace growth was marginally greater for tortoises that were supplemented with water although the small difference in growth rate was only detectable when the data from 1997 and 1998 were combined.…”

Section: Carapace Lengthmentioning

confidence: 89%

Return to the wild: Translocation as a tool in conservation of the Desert Tortoise (Gopherus agassizii)

Field

Tracy

Medica

et al. 2007

Biological Conservation

View full text Add to dashboard Cite

inducing carelessness in water conservation. In addition to generally investigating the efficacy of translocation, we compared the effects of continuing with the effects of ceasing the holding facility's water supplementation regimen. After exposure to one of the two water regimens, all tortoises were given the opportunity to hydrate immediately prior to release.We examined behavior, body mass, carapace length, movement, and mortality of tortoises for two activity seasons following release to the wild. Water supplementation was correlated with high rates of carapace growth and distant movements by males after release.Lengthy movements following translocation may be problematic for conservation planning, but this should be evaluated in light of the goals and circumstances of each translocation project. Although the mortality rate was 21.4% in 1997, data suggest that drought conditions at the site rather than the translocation itself negatively affected the tortoises.None of the tortoises died during their second season at the site. Our results indicate that translocation should be considered a useful tool in conservation of the Desert Tortoise.

show abstract

“…Further, EP leatherback populations are in danger of becoming extinct within the next 20 yr (Spotila et al 2000), whereas NA leatherback populations are stable or decreasing only slightly (Troëng et al 2004), and some are increasing (Dutton et al 2005). Such morphometric and reproductive traits as those enumerated above are influenced by resource quality and availability for sea turtles (Bjorndal 1982, Limpus & Nicholls 1988, Hays 2000, Solow et al 2002, Broderick et al 2003) and other reptiles (Congdon et al 1982, Wikelski & Thom 2000. For example, distinct patterns of seasonal and long-term reproductive output between populations of green turtles Chelonia mydas were attributed to differences in energy available from their respective diets (Bjorndal 1982).…”

Section: Introductionmentioning

confidence: 99%

“…In marine ecosystems, climate and oceanographic processes that drive resource availability (i.e. El Niño-Southern Oscillation [ENSO], North Atlantic Oscillation [NAO]) can have profound impacts on marine animal populations (Stenseth et al 2002) through constraints on energy budgets, and thus can influence body size, condition and growth (Wikelski & Thom 2000), reproductive output (Limpus & Nicholls 1998, Solow et al 2002, and population dynamics (Trillmich & Limberger 1985, Hays 1986, Schreiber & Schreiber 1989, Jenouvrier et al 2005. Therefore, studies of marine animal bioener-getics must account for the effects of environmentallydriven resource availability on resource allocation strategies and their consequences for marine animal life-history traits and population dynamics.…”

Section: Introductionmentioning

confidence: 99%

Energy budget calculations indicate resource limitation in Eastern Pacific leatherback turtles

Wallace

Kilham²,

Paladino³

et al. 2006

Mar. Ecol. Prog. Ser.

View full text Add to dashboard Cite

Resource availability constrains energy allocations to competing functions such as growth and reproduction, and thus influences animal life-histories and population dynamics. Leatherback turtles Dermochelys coriacea are critically endangered and exhibit physiological and life-history traits unique among marine reptiles. In addition, leatherback nesting populations in the North Atlantic (NA) are, on average, larger, produce more eggs, exhibit shorter remigration intervals (RIs, time between nesting seasons), and generally demonstrate more stable population trends than Eastern Pacific (EP) nesting leatherback populations. In order to compare energy requirements of inter-basin leatherback populations, we estimated costs associated with reproduction to calculate the energy budgets of leatherback populations from the EP and the NA. Our estimations illustrate that in contrast to reported trends in RIs of these populations (EP = 3.7 yr; NA = 2 yr), NA leatherbacks should require RIs between 1.5 to 4 times longer than their EP counterparts to accumulate sufficient energy to return to their nesting beaches for an entire reproductive season. These results indicate that resource limitation might lengthen RIs for EP leatherbacks compared to NA leatherbacks, thus decreasing the EP population's reproductive success and increasing its exposure to risk of fisheriesrelated mortality. We hypothesize that stochastic resource availability related to El Niño-Southern Oscillation (ENSO) is exacerbating the effects of high incidental fisheries mortality, resulting in plummeting EP leatherback populations. Therefore, management strategies for fisheries should allow little, if any, mortality of Pacific leatherbacks if there is to be any reasonable hope for recovery of this population.

show abstract

Marine iguanas shrink to survive El Niño

Cited by 180 publications

References 9 publications

Shifts in frog size and phenology: Testing predictions of climate change on a widespread anuran using data from prior to rapid climate warming

Shifts in frog size and phenology: Testing predictions of climate change on a widespread anuran using data from prior to rapid climate warming

Return to the wild: Translocation as a tool in conservation of the Desert Tortoise (Gopherus agassizii)

Energy budget calculations indicate resource limitation in Eastern Pacific leatherback turtles

Contact Info

Product

Resources

About