The effects of climate change are particularly evident in dry environments, where resources are scarce and subject to seasonal availability. Nevertheless, the demographic mechanisms through which the seasonal climate affects the persistence of the population remain largely unknown. Using detailed life history data collected by the Kalahari Meerkat project between 1997 and 2016, scientists from the universities of Zurich and Cambridge have already evaluated how Suricata suricatta will cope with future changes in seasonal rainfall and temperature.
Surikats are co-operative livestock breeders who live in social groups. A dominant woman monopolizes most of the reproduction while subordinate assistants support the raising of her offspring. Changes in the physical and social environment affect the growth, survival and reproduction of the surikata. For example, damp and warm conditions at the beginning of summer increase the growth, survival and network production of these animals. Conversely, high population density and cold weather in winter reduce individual growth and survival.
Seasonal dynamics atter
The Kalahari Desert in South Africa is expected to become drier and warmer as a result of climate change. The new study examines how steadily rising summer temperatures and precipitation fluctuations will affect body mass and surikate growth, resulting in lower levels of reproduction and survival of the offspring. This, however, is not the only finding of the study.
"In addition to the usual practice of modeling the average annual dynamics, we looked at the seasonal dynamics more closely and developed a specific model of climate change," said Maria Pann from the Department of Evolutionary Biology and Environmental Studies at the University of Zurich. "We have found that the picture is more complex: seasonality is important because improving conditions in one season can partially counteract worsening conditions next season."
Hotter winters can alleviate the negative effects
The team associates observed changes in growth, survival and reproduction with changes in seasonal rainfall and temperature. Using these links in a population projection model, scientists predicted population dynamics for the next 50 years, creating different scenarios based on a climate change report released by the National Center for Atmospheric Research (NCAR).
The data show that the combined effects of hotter and drier summers could endanger the stability of the population of suckets. The prognosis of the study has produced fewer generations, resulting in fewer aides in the population. In this scenario, the population of the suracians collapsed, increasing the risk of collapse of the population.
Conversely, the negative effects of less rainfall in the summer would be relieved to the extent that the winters become warmer, allowing the surikates to gain weight and increase reproduction. Taking into account these adverse seasonal changes leads to a different scenario where the likelihood of extinction is less severe and the surikata will continue to exist in 50 years.
Link between seasonality and population dynamics
"The effect of environmental changes on the population depends on how individuals interact with the biological and physical environment and how these interactions will change over time. Our study shows that we need to accurately identify these interactions, especially with regard to how these interactions vary between seasons to predict the vulnerability of the population to climate change, "said Arpath Ogul, senior research author and professor of environmental ecology in the Department of Evolutionary Biology and Environmental Studies at the University of Zurich.
Professor Tim Cutton-Brock, co-author of Cambridge University and project founder Kalhari Meerkat, adds: "Our work emphasizes the importance of long-term, individual surveys that stretch over several decades. it is possible to assess the effect of climate change on animal populations and to understand the environmental mechanisms that are responsible for them.
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Materials provided by University of Zurich, Note: Content can be edited for style and length.