Endangered Prince Albert Vygie Succumbs to Climate Change and Human Pressures

Researchers have sounded the alarm for the critically endangered Prince Albert vygie (Bijlia dilatata), a dwarf succulent native to the arid regions of the Western Cape, South Africa. According to studies by the South African Environmental Observation Network (SAEON), this plant species, already listed as endangered on the Red List of South African Plants of the South African National Biodiversity Institute’s Threatened Species Programme, is being pushed further towards the brink of extinction due to a combination of climate change impacts and anthropogenic threats.

Located in the endemic-rich Prince Albert region, populations of the Prince Albert vygie have been on a steady decline for the last two decades. The concerning trend was identified through extensive research conducted by Sue J Milton and Helga van der Merwe, who have noted significant population density declines across various Biijlia dilatata sites. The disparities in population health are attributed to a range of factors including elevation, rainfall patterns, and land use, with higher elevation sites faring slightly better for sustaining these succulent populations, offering cooler environments and a buffer against the increasingly hot climate.

However, challenges persist as the species already spans a narrow altitudinal range and options for natural refuge are limited. Furthermore, microsite conditions, profoundly influenced by grazing intensity, play a critical role in the survivability of the vygie, with high grazing pressures reducing essential shade and increasing temperatures at ground level.

The importance of nurse shrubs has also been underscored in providing shade and cooler microclimates essential for the vygie's survival. However, these nurse shrubs have been significantly impacted by prolonged periods of drought, further compounding the plant's vulnerabilities.

The threat of intense grazing is twofold: it reduces the availability of nurse plants and can lead to direct damage through trampling or consumption. Moreover, the lack of recruitment, the integration of new plants into the population, especially after periods of good rainfall, suggests additional stressors like a depleted seed bank or poor flowering and seed set in preceding years.

To make matters more precarious, illegal collecting of succulents remains a persistent and significant threat, putting additional pressure on the dwindling populations of the Prince Albert vygie. Consequently, conservation strategies have been posed, emphasizing the need to include higher-elevation sites within protected area networks, and the implementation of more stringent measures against poaching activities.

This South African succulent species' predicament underlines the profound impacts of not only environmental change but also the need for improved conservation practices that address both natural and human-induced challenges.