Anthropogenic climate change is driving global biodiversity losses, with detrimental effects on ecosystem services and functions.

Industrialisation has already increased average biosphere temperatures by ~1.1C, with further rises of up to 5C predicted by 2100.

Climate change and associated weather events will lead to changes in species distributions, abundances, interactions, and, in some cases, extinction. These events have been seen across a range of insect communities, with some referring to these population declines as an “insect apocalypse”. 

Therefore, management systems must be put in place to protect insects from climate change. 

These include short-term impacts in the form of weather events affecting food availability, reproduction, etc., and longer-term impacts such as increased warming and changes in seasonality, leading to changes in species interactions and range shifts. 

Climate refugia 

Traditional protection of insects has generally consisted of surveys that note their presence or absence in a habitat and their behavioural responses to environmental extremes. Measures need to go beyond this if insects are to have the best chance possible of thriving in a changing climate. 

While insects have behavioural and physiological adaptations that can help reduce the impacts of climate change, it’s important to understand how environmental changes will affect them at macro (landscape) and microclimates. 

Research into microclimate diversity has only just begun, but evidence suggests that insects are most resilient to change when they live in complex communities amongst a species-diverse plant community, which combine to create microclimate refugia. 

Hedgerows and flower strips are examples of climate refugia in an agricultural habitat, acting as windbreaks and providing shelter from freezing conditions. 

Despite the importance of microclimates, so far our ability to identify them and quantify their ability to facilitate species success is limited. 

However, it seems that the most important refugia, and thus those that should be protected and maintained, are those that have the greatest potential to maintain high levels of species diversity under changing conditions. 

For example, cold rocky landforms (e.g., glaciers) in montane habitats have been shown to be less affected by atmospheric warming than surrounding snowfields, providing warm-stage refugia for cold-adapted ground-dwelling insects. 

If conservation efforts are to be maximised, the next step is to understand how the size and locations of refugia can mediate changes in insect populations caused by climate change. 

Landscapes managed by environmental agencies, such as nature reserves, are usually ecologically diverse and are therefore likely to contain climate change refugia. Therefore, agencies should develop tools to help identify and preserve these areas, as well as dispersal corridors leading to them.

Furthermore, the roles of mammalian ecosystem engineers (e.g., beavers) also need to be considered, since they can create localised climate refugia when altering the structure and composition of their habitats. 

So, developing management systems that include the conservation of larger vertebrates will benefit smaller animals, including insects. 

Ensuring that refugia are connected by a network of corridors will create ecological resilience and reduce the risk of population loss as refugia become more accessible.

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Freshwater insects

Freshwater insects can also be protected from climate change through a range of management options. Oxygen levels should be maintained or improved since insufficient levels can worsen the impacts of heat stress. This can be achieved by improving water quality and ensuring its flow is maintained. 

Pesticides have been shown to elevate the impacts of climate change in aquatic systems and can remain in these systems for a long time, so their use should be reduced and faded out where possible.

On a local scale, water bodies can be kept cool by the addition of shading and removing nearby drainage to increase the presence of cooling groundwater. 

A combination of these measures on a larger scale should create a landscape with a variety of thermal regimes, helping insects seek refuge from high temperatures.

A black beetle on a log.
A black beetle in a woodland, Nikola (Johnny Mirkovic/Unsplash)

Forests and woodlands

Controlled fires are commonly used in woodlands to help manage, regenerate, and diversify these systems. As these fires are confined to small areas, ground-dwelling insects can seek refuge in unburned areas before restoring communities in the burned areas by the following season. 

This could potentially be a way of countering the effects of extreme fires that are caused by extreme temperatures in ecosystems that rely on fires for continued function.

Creating patches of burned and unburned areas will provide refugia for insects while regenerating the forest. Avoiding this practice can result in a buildup of excess vegetation, fueling intense, destructive fires that will not provide wildlife with unburned pockets to shelter in.

This will lead to a loss of pyrodiversity (the diversity of fire patterns) and contribute to a decline in the variety of insects present in the affected areas.

When managing habitats faced with climate change and extreme weather events, it’s important to recognise that insects face multiple human-induced stresses that often interact.

For instance, insecticides can harm flower visitors, worsening the impact of unpredictable events. To effectively address insect declines, conservation efforts should integrate factors like habitat loss, invasive species, intensive agriculture, pollution, and other stresses rather than addressing them in isolation.

This comprehensive approach is crucial for stabilising or reversing insect population declines.