A team of scientists led by the Research Institute for Ecosystem Analysis and Assessment in Germany has identified significant declines in insect populations across Europe, most of them linked to human activities that affect insect habitats.
The research was focused on a comprehensive review of 82 previously unpublished studies of two major groups of insects.
In recent years, concerns about declining insect abundance and diversity have increased in many regions in Europe and North America. However, the trends scientists observed are highly complex.
For instance, after a species decreases, others often increase due to reduced competition. Moreover, the causes of the declines are multifaceted, are often elusive, and vary between regions, leading to significant challenges in addressing them.
To clarify these issues, the experts conducted a review of 82 existing studies which focused on the drivers of changes in various Central and Western European populations of two major insect groups, Carabidae (ground beetles) and Lepidoptera (including butterflies and moths).
Although some of these studies focused on one or the other group and some on both, all of them included population monitoring data spanning the last six years and focused on agricultural landscapes located mostly in the UK, Germany, and the Netherlands.
Although the analysis revealed both increases and decreases in diversity and abundance in both insect groups, declines were found to be more frequent, highlighting an overall declining trend for Central and Western Europe.
Moreover, the researchers found that human activities were the main drivers of observed changes in insect populations (both increases and decreases). Such activities include agricultural practices, urbanization, climate change, and nature conservation. While most of these activities do not affect insects directly, they nevertheless significantly impact their habitats.
These findings could help inform efforts to structure human activities in ways that reduce disruption to natural ecosystems while still meeting human needs. However, further research is needed to expand the monitoring of potential drivers of insect population changes while monitoring population trends themselves.
“Research into the root causes of insect decline is challenging, as it requires the understanding of processes that have been taking place years or even decades ago. In our study, we leveraged the wealth of published long-term data to gain insights into factors associated with the decline of insects in Europe,” the authors concluded.
The study is published in the journal PLoS ONE.
The decline of insects is a multifaceted issue that requires a combination of local, regional, and global efforts to address. Awareness and action are crucial to reverse this trend and maintain the ecological balance essential for life on Earth.
In recent years, many studies have confirmed significant declines in insect populations worldwide. These declines are concerning for several reasons:
Insects play crucial roles in ecosystems. They are pollinators, decomposers, and a vital food source for many animals, including birds, reptiles, and amphibians.
Many crops rely on insects, especially bees, for pollination. Without them, there would be significant implications for global food production and food security.
The decline of any species can lead to reduced biodiversity, which can make ecosystems less resilient to changes and stressors.
Urbanization, agriculture, and other human activities are leading to loss and fragmentation of habitats essential for insect survival.
Chemicals used in farming can be toxic to insects. Neonicotinoid pesticides, in particular, have been linked to declines in bee populations.
Altered weather patterns and increased temperatures can affect insect habitats, life cycles, and food availability.
Water, soil, and air pollution can all negatively impact insect populations.
Non-native species can outcompete or introduce diseases to native insect populations.
Consequences of insect declines
Many crops rely on insects for pollination. A decline in insect pollinators can affect food security.
Insects are a primary food source for many animals. Their decline can lead to declines in predator populations and overall ecosystem imbalance.
Insects play a key role in breaking down organic matter. Their decline can slow decomposition rates, affecting soil health and nutrient cycling.
Adopting integrated pest management, organic farming, or other sustainable agricultural practices can help.
Creating and maintaining green spaces, wildflower strips, and hedgerows can provide habitats and corridors for insects.
More research and consistent monitoring are needed to understand the extent of the declines and how best to address them.
Educating the public and policymakers about the importance of insects can lead to better decision-making and increased support for conservation efforts.
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