Resilience of vertebrate animals in rapid decline due to manmade threats

Resilience of vertebrate animals in rapid decline due to manmade threats
Conceptual summary of population resistance and recovery, and the main hypothesis tested in this study. (a) Conceptual representation of the resistance and recovery after a punctual disturbance affecting a population. In a population context, the system state is defined as the population size (y axis). The lightning represents a disturbance affecting a population. The stable 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 can be associated with a lack of resistance, the more negative r is, the less resistant the population is. On the other hand, recovery represents the rate of return to the undisturbed state. Then, positive values of r represent proxies of the recovery of the population, the more positive the value of r the faster the rate of recovery. (b) Graphical summary of the main hypothesis of this study. Here we hypothesize that if the resilience of vertebrate populations is decreasing over time, we should observe declines in resistance (negative r) and/or recovery (positive r) over time. Credit: DOI: 10.1111/ele.13927

Global change is eroding life on earth at an unprecedented rate and scale. Species extinctions have accelerated over the last 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 paralleled by a decrease in the resilience of ecological systems. As such, preserving resilience of ecosystems has become a major conservation objective.

Now researchers at the University of Bristol have examined how species are responding to the rising environmental pressures, demonstrating in findings published today in Ecology Letters, that the planetary scale of human impacts to wildlife is also accelerating resilience loss of vertebrates worldwide.

Dr. Pol Capdevila of the School of Biological Science said: "Global assessments of how the resilience of vertebrate species has changed over the last decades were absent before our study, rendering the assumption of global resilience loss untested.

"In this study, we evaluated how the resilience of vertebrate populations, including species of mammals, birds, amphibians, reptiles and fish worldwide, is changing over time. We also tested which could be the main factors accelerating the potential decline of resilience worldwide.

"Our study reveals a global loss of resilience across marine, freshwater and terrestrial ecosystems. Most importantly, we found that the cumulative effects of anthropogenic threats, such as , invasive species, habitat loss, pollution or exploitation are accelerating the loss of resilience."

As play key roles in ecosystems worldwide, the global signs of resilience loss suggest that vertebrate populations will be more vulnerable to future threats, what could trigger catastrophic loss of natural ecosystems function and services. In addition, the findings suggest that previous studies might have underestimated the extent of biodiversity loss and the impacts of anthropogenic threats.

The researchers will explore more in detail the effects of threats of different nature, such as climate change, or , on the resilience of species. 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 a strongest impact on the resilience of vertebrate populations."


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More information: Pol Capdevila et al, Global patterns of resilience decline in vertebrate populations, Ecology Letters (2021). DOI: 10.1111/ele.13927
Journal information: Ecology Letters

Citation: Resilience of vertebrate animals in rapid decline due to manmade threats (2021, November 18) retrieved 29 January 2022 from https://phys.org/news/2021-11-resilience-vertebrate-animals-rapid-decline.html
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