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Conceptual summary of population resistance and recovery, and main hypothesis tested in this study. (a) Conceptual representation of resistance and recovery after a point disturbance affecting a population. In a population context, the state of the system is defined as the size of the population (y-axis). Lightning represents a disturbance affecting a population. The steady state of the population is when the population growth rate (r) is 0. In this case, resistance represents the ability of the system to remain unchanged after a disturbance. Therefore, negative values ​​of r may be associated with a lack of resistance, the more negative r, the less resistant the population. On the other hand, recovery represents the rate of return to the undisturbed state. Then, positive values ​​of r represent approximations of population recovery, the more positive the value of r, the faster the rate of recovery. (b) Graphic summary of the main hypothesis of this study. Here, we hypothesize that if the resilience of vertebrate populations decreases over time, we should observe declines in resistance (r negative) and / or recovery (r positive) over time. Credit: DOI: 10.1111 / ele.13927
Global change is eroding life on earth at an unprecedented rate and scale. The extinctions of species have accelerated in recent decades, with the concomitant loss of the functions and services they provide to human societies.
A general assumption is that this current loss of global biodiversity is accompanied by a decrease in the resilience of ecological systems. As such, preserving the resilience of ecosystems has become a major conservation objective.
Now researchers at the University of Bristol have examined how species respond to increasing environmental pressures, demonstrating in results published today in Ecology letters, that the global scale of human impacts on wildlife is also accelerating the loss of resilience of vertebrates around the world.
Dr Pol Capdevila of the School of Biological Science said: “Global assessments of how the resilience of vertebrate species has changed in recent decades were absent prior to our study, making the hypothesis of a loss of untested global resilience.
“In this study, we assessed how the resilience of vertebrate populations, including mammal, bird, amphibian, reptile and fish species around the world, is changing over time. We also tested what could be the main factors accelerating the potential decline in resilience around the world.
“Our study reveals an overall loss of resilience in marine, freshwater and terrestrial ecosystems. Most importantly, we found that the cumulative effects of anthropogenic threats, such as climate change, invasive species, loss of habitat, pollution or exploitation accelerate the loss of resilience. “
While vertebrate species play a key role in ecosystems around the world, global signs of loss of resilience suggest that vertebrate populations will be more vulnerable to future threats, which could trigger catastrophic loss of function and services. natural ecosystems. In addition, the results suggest that previous studies may have underestimated the extent of biodiversity loss and the impacts of anthropogenic threats.
Researchers will explore in more detail the effects of threats of different kinds, such as climate change, habitat loss or invasive species, on species resilience. Dr Capdevila added: “Not only that, we will also explore how these multiple threats interact with each other, to identify which combinations of threats have the greatest impact on the resilience of vertebrate populations. ”
Consequences of the loss of endangered vertebrates
Pol Capdevila et al, Global models of declining resilience of vertebrate populations, Ecology letters (2021). DOI: 10.1111 / ele.13927
Provided by the University of Bristol
Quote: Resilience of vertebrate animals in rapid decline due to man-made threats (2021, November 18) retrieved November 18, 2021 from https://phys.org/news/2021-11-resilience-vertebrate-animals- rapid-decline.html
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