When you think of plants, the word “carnivorous” might not immediately spring to mind, but among the Earth’s weird and wonderful botanical species there are some bloodthirsty specimens. The Venus Flytrap is perhaps one of the biggest household names among carnivorous plants, and arguably the most popular (look at this plant in a Santa hat and tell me I'm wrong). If you’re a fan of these leafy murderers, there’s bad news afoot, as a study published in the journal Global Ecology and Conservation has warned that as much as a quarter of carnivorous plant species could be at risk of extinction. The culprits? Anthropogenic habitat degradation and environmental change.
The story of how plants developed a taste for blood is one of necessity, as plants in nutrient-impoverished areas adapted to fulfill a new niche by munching on insects and animals instead of soil-based nutrients. Unfortunately, this puts carnivorous plants at a disadvantage if conditions suddenly change, having little in the way of backup nutrition if one day all the animals should leave. The makes them, as the study authors poetically put it, “harbingers of anthropogenic degradation and destruction of ecosystems.” A heavy burden for a hungry plant.
Their delicate existence means carnivorous plants are often the first to go when humanity plonks a development down in their neighborhood and slashes biodiversity – and it’s not just land use change they have to fear. Ecological processes such as eutrophication (a process that saps the oxygen from aquatic environments, commonly triggered by nutrient runoff from agriculture) are also a death knell for many carnivorous plant species.
“Many of the world's 860 species of CPs are found in wetland habitats, which represent some of the most cleared and heavily degraded ecosystems on Earth,” wrote the study authors. “Global diversity hotspots for CPs are likewise located in some of the most heavily cleared and disturbed areas of the planet - southwestern Western Australia, Southeast Asia, Mediterranean Europe, central eastern Brazil, and the southeastern United States - placing their conservation at odds with human developmental interests.”
The final nail in the coffin for these species is that the increasing climatic changes associated with global warming (such as high temperatures and little water) will leave carnivorous plants with nowhere to turn for the conditions they need to survive.
Taking all this damning information into account, the researchers on this paper carried out the first systematic assessment of the conservation status and threats to carnivorous plants across the globe. The mammoth project looked at 860 species from 18 genera, resulting in ten recommendations as to how to save the species.
The results make for grim reading, with around 30 percent of species scoring between Near-Threatened and Critically Endangered. Threats included agriculture and aquaculture, energy production and mining, and climate change, with around a quarter of all species being impacted by three or more threat categories.
“The complex and specialised ecological requirements of CPs, together with the multifaceted threats they face, make conservation difficult and repatriation even to restored areas challenging,” wrote the researchers. “As the number of vulnerable, endangered and extinct carnivorous plant species continues to grow, despite significant conservation efforts in many regions and greater awareness of their ecological requirements, it is clear that a paradigm shift is required in our approach to the preservation of this unique group of plants in order to achieve long-term conservation successes.”