Yellow oleander, Thevetia peruviana. Single open flower and bud growing in Phrao, Chiang Mai, Thailand. (Photo courtesy of FlowerPhotos/Universal Images Group, Getty Images)
Urban spaces in KwaZulu-Natal are filled with invasive species that need to be removed, according to research by master's students employed at the Natural Sciences Collection Institute.
A study by Maxine Manickum investigated the diversity of trees in urban parks in the eThekwini municipality.
“Invasion of alien plants is significant and coastal terrestrial vegetation is being reduced,” she said in a press release. “Only 26% of that land is in its natural, undegraded state.”
Everything is interconnected in an ecosystem, and with only 26% of land in an undegraded state, if a portion of biodiversity is removed or destroyed, “essentially It deprives the species of a food source or shelter,” says Manickam. said to email and guardian. “Some species can adapt, but some species are specific to certain regions. It's like a ripple effect.”
All 13 parks studied by Manickam had invasive species, which she said was a “worrying trend”.
“According to the National Environment Management and Biodiversity Act 2004, there are three categories of invasive species. Categories 1a and 1b should be removed, while categories 2 and 3 are allowed,” she said. Ta.
yellow oleander (Cascabella Tebetia) and Brazilian pepper tree (Schinus terebentifolia) were classified as category 1b and were commonly seen in parks.
Yellow oleanders, like pepper trees, “could potentially compete with and displace native species,” he said. invaders of south africa. Both species are poisonous.
The problem with these non-native species is that they grow faster, produce more seeds, and are more efficient at dispersing seeds.
“When it comes to dealing with invasive species, categories 1a and 1b should be removed and replaced with native species,” Manickam said.
“Also, all parks need to be managed and planted with trees that are appropriate for each location, rather than just what can be planted.Management of invasive species in urban parks requires many considerations. there is.”
The importance of native species cannot be underestimated, she says. These contribute to biodiversity conservation and ecosystem resilience, and “represent a valuable asset in the park's ecosystem.”
They provide many other benefits to the general ecosystem. These include “the potential to enhance native flora and fauna while enhancing the ecological health, interconnectedness and biological vitality of the soil.”
“Native species improve ecosystem health, but invasive species compromise ecosystem health by jeopardizing ecosystem structure and operation and reducing habitat potential,” Manickam said. said.
The South African National Biodiversity Institute classifies invasive plant species as:
Category 1a:
Invasive species that require forced management. Remove and destroy. Specimens of species listed in Category 1a must be eradicated from the environment by law. No permits will be issued.
Category 1b:
An invasive species that requires mandatory management as part of an invasive species management program. Remove and destroy. These plants are considered to have a high invasive potential and, if introduced, may be subject to government-supported invasive species management programs. No permits will be issued.
Category 2:
Invasive species regulated by region. A demarcation permit is required to import, possess, cultivate, propagate, move, sell, purchase, or receive as a gift any plant listed as a Category 2 plant. If Category 2 plants are present in the riparian zone, a permit will not be issued.
Category 3:
Invasive species regulated by activity. A separate plant permit is required to carry out the following restricted activities with respect to Category 3 species: importing, possessing, cultivating, propagating, moving, selling, purchasing or receiving as gifts. If Category 3 plants are present in the riparian zone, no permit will be issued.