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Eurasian otters threatened by urban development in Hong Kong

In the heart of one of the globe’s most active cities, Hong Kong, the Eurasian otter (Lutra lutra) currently faces significant challenges. Recent findings from a paper in Oryx—The International Journal of Conservation, casts a spotlight on these challenges.

Threatened habitat

Within the bustling confines of Hong Kong, the Eurasian otter, a species dependent on lowland wetlands, faces major threats. 

This vulnerability stems mainly from the metropolis’ pace of urban development and a proposed government construction project targeting otters’ primary habitat.

Focus of the study

The study delves deep into 131 years of data, offering an unprecedented view of the otter’s historical distribution in Hong Kong. The findings indicate that these creatures were once more prevalent than they are today.

According to the experts, between 1890 and 2020, there has been a worrisome reduction in the Eurasian otter’s presence in Hong Kong. Notably, Hong Kong’s Deep Bay wetlands have been identified as the lifeline habitat for these creatures, a revelation crucial for conservation discussions.

The Eurasian otter, while spread across Europe, Asia, and North Africa, finds its status in Asia quite shaky. Despite being marked endangered, there’s a notable gap in research surrounding its Asian existence and challenges.

What the researchers learned 

The analysis revealed that urban growth from the 1930s is the main cause behind the dwindling otter numbers. Otters’ reliance on lowland wetlands makes them an easy target for urban development threats. 

Accelerating this issue is the city’s infrastructural evolution and subsequent water pollution, which erodes these wetlands, impacting otters and their food sources.

From the examined records, a significant 80 percent referred to the Yuen Long floodplain, linked to the Deep Bay catchment. These records, from the 1900s through 2019, underscore this region’s importance for otter conservation in Hong Kong.

Historical data 

To assemble this dataset, the scientists undertook a comprehensive review of all otter-related records from various publications from 1890 to 2020, including a detailed examination of 14,231 newspaper articles. 

The increasing reliance on historical data, like newspapers and traditional ecological records, has become instrumental in understanding species and ecosystem patterns in the absence of contemporary ecological data.

Public support is needed

“The otter is a resilient species and can live in human-dominated landscapes, provided that healthy riverine or coastal ecosystems are available,” said Michael Ka Yiu Hui, a wildlife conservationist at the Kadoorie Farm and Botanical Garden in Hong Kong. 

“Urbanization leads to the direct loss of otter habitat, and the extensive river channelisation scheme and pollution problem appear to be the major drivers of local otter decline. The plight of the local Eurasian otter needs to be widely publicized to garner public and government support and galvanize immediate conservation efforts across society.”

Study significance 

Co-author Bosco Pui Lok Chan, a conservationist at the World Wildlife Fund Hong Hong, also stressed the study’s value for the holistic management of Hong Kong’s otters and their aquatic surroundings. 

“Conservation action is particularly crucial with the looming Northern Metropolis mega development plan recently released by the Hong Kong government, which will drastically change the rural landscape of the ecologically invaluable Yuen Long floodplain,” said Chan. 

“A holistic nature-positive land-use plan must be designed to balance economic development and nature conservation, and ecologically sensitive areas must be preserved.”

The study was published by Cambridge University Press on behalf of the wildlife protection organization Fauna Flora International.

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