DNA reveals clues about how species adapt to climate change – 09/26/2024 – Basic Science

What would the planet look like without the diversity of animals, plants and microorganisms? More boring and less functional, to be sure. But from a scientific point of view, the situation would be much more dramatic, because we would lose information about the origin and evolution of life.

Now, brace yourself: Given human-driven climate change, this pasteurized world may not be too far away. Yet despite the proximity, the potential impacts and responses of biodiversity to the crisis are still poorly understood.

We know that in response to changes, individuals that form part of a population under natural conditions can move to pursue more suitable climates, or adapt to new conditions, either by plasticity AppearanceEither by Adaptation evolutionary.

The first concerns the ability of organisms to change the properties of organ functions, behavior, and/or morphology according to environmental conditions, while the second promotes genetic modifications. Time, dispersal capabilities, and genetic diversity are essential conditions for the operation of these mechanisms..

Having established the rules of the game, it is up to climate change biology to answer whether there are winners and losers in this race. Amphibians and reptiles, for example, which are ectothermic animals—that is, able to control their body temperature through behavior, moving between sun and shade, among other things—rely on the heat or cold of the environment to keep their internal temperature within the appropriate range for survival; they are therefore more vulnerable to impacts. In these organisms, even small environmental differences can severely limit activity time, reduce energy acquisition, and limit population growth rates, thereby increasing the risk of local extinction.

Although natural selection can shape patterns of phenotypic and genetic variation, one of the major challenges facing science is to study the empirical evidence for selection and adaptation, and how these processes affect the persistence of biodiversity. This is even more challenging for natural populations, which lack empirical references and have many knowledge gaps. For this reason, the impact of climate change is often analyzed from stabilizing perspectives that assess whether species are able to withstand the warmer, more stressful climates expected in the future, but do not take into account the possibility of evolutionary adaptations.

More than just a scenario, environmental traits can select for characteristics of populations and species whose DNA collects information about the conditions under which particular genetic variants have been selected by environmental pressures. This variation, called adaptive inheritance under environmental selection, is able to reveal the conditions under which more resistant genotypes have been selected, and thus bring Visions Regarding advance adaptations that would help maintain population health in future climate scenarios.

My lab The National Amazonian Research Institute (INPA) seeks to obtain empirical evidence of climate adaptation in natural populations of Amazonian organisms that could help them escape the challenges posed by climate change. In collaboration with researchers from the University of Brasilia (UnB), Gothenburg (Sweden), and Kew Botanic Gardens (UK), we recently published in the journal Diversity and distributions A study reinforces this understanding.

Based on genomic data from a species of lizard (calango da mata; Kentropyx calcarata), We conduct genome-environment association analyses, which integrate empirical data from natural populations with predictions of climate and land use (such as deforestation). The analysis is conducted under two possible scenarios: moderate and extreme, where we are moving towards more carbon emissions, more extreme temperatures, and more deforestation.

The aim is to infer the potential for evolutionary rescue across the Amazon. In other words, we assess the potential for pre-existing climate adaptations to spread in the future across the distribution of Kalango species through dispersal, thus preventing local extinctions.

The genetic diversity of the studied kalango was divided into two large groups: one distributed in the drier and more seasonal areas of southwestern Amazonia and the transition between Amazonia and Cerrado, and the other in the wetter and less seasonal areas of central Amazonia.

In the moderate scenario, populations adapted to drier and more seasonal areas would be able to maintain themselves and, in the future, reach areas where more vulnerable populations would lose suitable areas for distribution, thus saving them from local extinction. However, in the extreme scenario, there would be a large loss of potential distribution and very low chances of evolutionary rescue among the most vulnerable and least vulnerable populations, indicating a high risk of local extinction.

If there is governance to maintain a temperate scenario in the future, populations in the Amazon-Cerrado ecological transition zone, which are currently under strong impact and pressure from deforestation, could be important sources of adaptive genetic diversity to prevent the most vulnerable populations from becoming extinct. Only forest protection and climate change mitigation can promote evolutionary rescue and prevent significant loss of biodiversity of ectothermic organisms in the Amazon.

Our results highlight the importance of understanding generally neglected processes, such as species adaptability, to improve predictive models, as well as to suggest what can be done to mitigate and halt the adverse impacts on this very high biodiversity in increasingly challenging climate scenarios.

It is essential to assess different species ecologically and at different biological and spatial scales to appreciate the generality of these results and to allow us to identify the characteristics that confer vulnerability and resistance, as well as the main types of climate impacts. Much remains to be done from a scientific and conservation standpoint. The race is against the clock of human action.

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Fernanda B. Wernick is a biologist and researcher at the National Institute of Amazonian Research (INPA).

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