African Bermuda-grass naturalisation reveals policy gaps
A study reveals that African Bermuda-grass has naturalised in the Himalayas and Western Ghats, highlighting a 30-year delay in species identification that hinders management.
Kuntal Saha, a taxonomist from the Forest Research Institute, Dehradun, discovered African Bermuda-grass growing along a roadside in Tangmarg, Jammu and Kashmir, in 2023. This discovery was part of a decades-long survey that began in 1995 when Saha's mentor, retired Forest Service Officer Manoj Chandran, collected an unknown species of the grass in Tamil Nadu. The researchers recently reported that Cynodon nlemfuensis, a species native to Central and East Africa, has naturalised in two Indian biodiversity hotspots: the Himalayas and the Western Ghats. Naturalisation occurs when introduced species successfully sustain self-reproducing populations in the wild.
Systemic gaps delay identification
It took the team nearly 30 years to report the African Bermuda-grass found during the 1995 survey. According to the study, the average delay between the first identification and the publication of naturalised species is 27 years, though some cases can lag by a century. Ninad Avinash Mungi, a researcher at Aarhus University, Denmark, noted that the study highlights the challenge of correctly identifying lesser-known alien species. Mungi explained that many grasses are difficult to identify outside of the flowering season or in areas with heavy grazing.
Achyut Kumar Banerjee, an assistant professor at Azim Premji University, Bhopal, mentioned that the Indian Alien Flora Information Database (ILORA) faces identification hurdles with grasses. He observed that type specimens for comparison are often unavailable in India and are found in foreign herbaria, such as one located in Belgium. Banerjee pointed out that national and regional Indian herbaria frequently lack digitised collections, which slows the process of checking new collections against type specimens.
Poor surveillance facilitates naturalisation
Most non-native plants fail to adapt to new environments, but some become naturalised by reproducing without human intervention. The study notes that species can become invaders that alter local ecosystems. The economic cost of biological invasion in India was estimated to be between $127 billion and $182 billion between 1960 and 2020, according to Alok Bang, an invasion biologist at Azim Premji University.
Bang stated that a species cannot be managed until it is detected and communicated to authorities. He argued that while species like Bermuda grass may have economic potential as fodder, this does not justify introduction when the ecological costs are shared. The researchers observed the grass colonising highway roadsides, open grasslands, and disturbed habitats. Saha noted that finding the grass in the cool climate of Kashmir and Uttarakhand demonstrated its remarkable ecological adaptability compared to its presence in warmer regions like Kerala and Tamil Nadu.
