The role of climate change in pollinator decline

The ecological relationship between pollinators and plants is mutualistic: generally insects obtain nourishment through nectar

by Lorenzo Ciotti
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The role of climate change in pollinator decline

The ecological relationship between pollinators and plants is mutualistic: generally insects obtain nourishment through nectar. Some non-nectariferous orchids, on the other hand, imitate the shape of the female pollinators, which try in vain to mate and thus load up with pollen.

The pollinating insects play a crucial role in fruit growing and horticulture: in fact without their activity there would be no production of apples, pears, peaches, cherries, plums, apricots, almonds, strawberries, etc.

The relationship between pollinating insects and plants is also studied from an ecological point of view as a biological indicator in environmental monitoring. The role of climate change in pollinator decline across the Northern Hemisphere is underestimated, interesting research published on the The Science of the total environment, explained: "Pollinator biodiversity loss occurs at unprecedented rates globally, with particularly sharp declines documented in the North Temperate Zone.

There is currently no consensus on the main drivers of the decline. Although climate change is expected to drive biodiversity loss in the future, current warming is often suggested to have positive impacts on pollinator assemblages in higher latitudes.

Consequently, pollinator conservation initiatives in Europe and the USA tend to lack climate adaptation initiatives, an omission of which may be risky if climate change has significant negative impacts on pollinators. To gain an understanding of the impacts of climate change on pollinator biodiversity in the Northern Hemisphere, we conducted a literature review on genetic, species and community level diversity.

Our findings suggest that global heating most likely causes homogenization of pollinator assemblages at all levels of pollinator biodiversity, making them less resilient to future stochasticity. Aspects of biodiversity that are rarely measured (e.g.

genetic diversity, β-diversity, species evenness) tend to be most affected, while some dimensions of climate change, such as fluctuations in winter weather conditions, changes in the length of the vegetational season and increased frequency of extreme weather events, that seldom receive attention in empirical studies, tend to be particularly detrimental to pollinators.

Negative effects of global heating on pollinator biodiversity are most likely exacerbated by homogenous and fragmented landscapes, widespread across Europe and the US, which limit opportunities for range-shifts and reduce micro-climatic buffering.

This suggests the need for conservation initiatives to focus on increasing landscape connectivity and heterogeneity at multiple spatial scales."