Study raises concerns about 'over-conservation'

While conservation efforts often focus on iconic and charismatic species, such as the giant panda or orangutan, a recent article suggests that an overemphasis on boosting the populations of "flagship" animals can actually have negative effects on the overall health and balance of ecosystems.

Chinese researchers are warning that the pursuit of ever-increasing numbers of certain species in China is diverting resources from other areas in need of attention and potentially leading to unintended ecological consequences.

The article, titled "Are we overconserving charismatic species?", published on Dec 3 in PLOS Biology, a monthly peer-reviewed scientific journal covering all aspects of biology, highlights examples where well-intentioned conservation programs have inadvertently disrupted ecological balance.

The authors point to successful efforts to recover populations of endangered species such as milu deer (Elaphurus davidianus), crested ibis (Nipponia nippon), and the Chinese giant salamander (Andrias davidianus). However, they argue that the single-minded focus on the population numbers of these specific species has overshadowed the need for a more holistic, ecosystem-based approach. "Many practitioners seem to equate a large quantity of a charismatic species with a high-quality ecosystem," said Shi Haitao from Hainan Normal University in Haikou, Hainan province, who is one of the authors. "This oversimplification can cause well-known problems."

The authors highlight three examples from China where oversimplified conservation priorities led to negative outcomes.

One example is the Chinese giant salamander. Efforts to replenish wild populations by releasing artificially bred individuals have been complicated by the discovery that what was once considered a single species is a complex of at least seven cryptic species. Releasing mixed populations from different locations has led to genetic pollution, diluting the natural and wild populations.

Similarly, the crested ibis has seen a dramatic increase in numbers thanks to dedicated conservation efforts. However, the study points out problems like inbreeding depression, increased mortality and highly dense populations in some areas.

Changes in agricultural practices, such as shifting to organic black rice farming, had to be made in order to protect the habitat for the species. As a result, the authors argue that the reintroduction of the bird to some areas not within its historical distribution range might have a negative impact on local communities and economies.

Milu deer, also known as the Pere David's deer, once extinct in the country, has also experienced a remarkable recovery. Yet, the growing population is nearing the carrying capacity of available habitats, leading to calls for artificially created microhabitats — a small, localized environment within a larger habitat that has unique conditions and supports specific flora and fauna — to accommodate the overabundance of the deer.

Professor Liu Yang, from the School of Ecology at Sun Yat-sen University in Shenzhen, Guangdong province, who is another author of the article, said that these cases highlight the dangers of focusing solely on increasing the populations of charismatic species. "Such practices can lead to genetic pollution, population imbalances and the need for increasingly artificial interventions to manage species that have outgrown their environment," he said. "A truly healthy ecosystem requires a complex interplay of biotic and abiotic factors."

The article calls for a shift in conservation strategy, advocating for a dynamic and adaptive approach that takes into account the complexities of ecological systems and the impacts of global change. Instead of simply aiming to maximize the populations of flagship species, conservation efforts should focus on maintaining overall ecological equilibrium. "The effectiveness of ecological restoration should not be only measured by species abundance," Liu said. "We need to allocate limited resources for the protection of the ecological environment and to mitigate excessive human interventions."

The authors emphasize that prioritizing reintroduction should be done where the species formerly thrived but is now extinct, and that high numbers of a single charismatic species in the original ecosystem should be avoided. For example, Liu said, more than 5,000 milu deer live in the Dafeng Milu National Nature Reserve in Jiangsu province, and that is "certainly approaching the upper limit of their carry capacity".

They also noted that there is relatively poor consensus as to what a comprehensive evaluation entails, so practitioners are likely to continue relying on an increasing population as the primary indicator of success to secure funding.

Although there has recently been more emphasis placed on protecting whole ecosystems, charismatic species conservation is still prevalent in China and elsewhere. "Conservation programs that aim to preserve and restore ecosystem functions are a more effective use of limited resources, and are less likely to have unintended consequences," Liu said.

chenliang@chinadaily.com.cn