SDG 14 | submarine life
Animals are able to overcome changes in their habitat, but the cost of doing so is shortening their lifespan
Adapt, leave or die. These are the options of flora and fauna in the face of climate change. Rising temperatures are moving many species to ‘cooler’ latitudes or, in the case of many flowers, the early arrival of spring heat has changed the flowering roadmap. “However, there are many species and, above all, plants that cannot be moved,” explains Iván Gómez-Mestre, a researcher at the Doñana-CSIC Biological Station. “They can only adapt or perish,” he adds.
Oceanic corals “boil” underwater and more than 25,000 species are endangered by environmental changes due to the impossibility of adapting to them. Many others, yes, they are getting it, but paying a high price. “The ability of animals and plants to respond to environmental changes is extremely common and is the most effective strategy for survival,” says Gómez-Mestre. However, the cost is high.
For the first time, scientists from the CSIC, specifically from the Doñana Biological Station, have managed to demonstrate the morphological and behavioral changes of the species and the impact these have on the lives of the animals themselves.
The discovery has come through the observation of the tadpoles that inhabit the waters of Doñana and the Sierra Norte de Sevilla. Faced with a risk of predation, for example, they modify their anatomy by producing larger tails, reduce their growth rate and have higher antioxidant enzyme activity. “Different environmental factors affect them in different ways,” says Gómez-Mestre.
This is known as “phenotypic plasticity” whereby organisms modify their characteristics to fit different environments. “We already had him identified,” says the CSIC researcher. “Now we’ve found that just maintaining that ability to change is expensive,” he says.
In constant “surveillance”
This ability “is a constant state of alert,” he says. Maintaining this surveillance machinery “has a metabolic cost,” she warns. “Organisms pay a metabolic price just for maintaining the ability to change in the face of environmental challenges, even if they don’t,” she says.
In this research, the team from the Doñana Biological Station-CSIC has shown that, for amphibian larvae, simply maintaining this adaptation potential, even if these changes do not occur due to the lack of interaction with predators, for example, has an associated a higher physiological cost that is expressed in the form of oxidative stress.
This type of stress is caused by an imbalance between the production of reactive oxygen species and the ability of a biological system to rapidly neutralize the reactive intermediates or repair the resulting damage. “An increase in this affects the ends of the chromosomes, eroding them and affecting the quality of life,” warns Gómez-Mestre. “A higher oxidative stress could translate into a more deteriorated physical condition, reduced fertility and a shorter life expectancy,” says the CSIC research.
Most of the changes observed in organisms in the face of global change, such as changes in the date of flowering or migration, are due to plastic responses, that is, changes in their characteristics in response to an environmental signal. However, this responsiveness has limits.
“All organisms are evaluating our environment to try to adjust to environmental changes and conditions,” reveals the CSIC researcher. “It has its cost,” he adds. These costs can limit evolution and, therefore, the response capacity of species in the face of global change, conclude the authors of the research.
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