How human infrastructure threatens biodiversity by squeezing sandy coasts

Area of Science:

• Ecology
• Coastal Science
• Conservation Biology

Background:

• Coastal dunes are vital ecosystems providing flood protection, drinking water, and biodiversity.
• Habitat zonation along sea-to-land gradients is crucial for dune ecosystem functioning.
• Infrastructure development is reducing the available width of natural dune ecosystems globally.

Purpose of the Study:

• To determine the required undisturbed coastal width for supporting diverse dune habitats and species assemblages.
• To quantify the relationship between coastal width and plant/habitat diversity.
• To assess the effectiveness of management interventions in mitigating biodiversity loss.

Main Methods:

• Investigated plant and habitat diversity across 614 plots along 47 sea-to-land transects.
• Conducted study in the southeastern USA and the Netherlands.
• Analyzed management measures implemented along transects.

Main Results:

• A linear relationship exists between habitat diversity and species richness in dune systems.
• Plant and habitat diversity nonlinearly depend on coastal width, with 75% diversity reached at 800m (USA) and 1800m (Netherlands).
• Significant portions of coastlines in the USA (79%) and Netherlands (66%) have dune areas narrower than required, compromising biodiversity.

Conclusions:

• Lack of coastal width, or 'coastal squeeze,' is a major threat to dune biodiversity worldwide.
• Establishing or expanding nature reserves is crucial for conserving wide dune systems.
• Targeted management strategies can partially mitigate biodiversity losses caused by coastal squeeze.