Why we need wetlands: protecting aquatic ecosystems

20 January 2017

As an Assistant Professor at the Ecology and Conservation Laboratory at the National Taiwan University, Dr Rita Yam’s research encompasses aquatic ecosystems such as rivers and wetlands, as well as applied science, like her current work on constructed wetlands.

Yam’s office is both in the lab and out in the wetlands themselves, as she needs to analyse chemical and physical aspects of the delicate ecosystem, including plant growth patterns, pollutant absorption rates, pest control, and design behaviors for waste reduction. 

The sites can be enormous, and helping constructed wetlands succeed takes considerable care. As Yam says, “it’s not just lab science, but also management of real places; you don’t get more applied science than this.”

Initially a biology student, she sought to widen her interest in ecology, which took her to the Centre for Ecology and Hydrology in the UK as a Croucher Fellow, incorporating physical science and engineering into her research. 

“The study of aquatic systems involves the hydrology, chemical makeup, and environmental impact on ecosystems. Pure ecological science is very important, but the addition of more engineering and policy-related work showed me that I wanted to be at the front lines too,” she says. 

Dr Rita Yam

With a renewed focus, Yam went on to PhD at the University of Hong Kong in river ecology and a post-doctoral fellowship at the Wallingford Center for Ecology and Hydrology, covering the development of conservation policy, the impact of engineering structures, indices for aquatic ecosystem statuses, and the interaction of physical and chemical factors on ecosystems.

A feathery element pops up in most of Yam’s projects, surprising for someone whose focus is seemingly lower than the skies. “My doctorate supervisors were heavily involved in conservation, and I volunteered a lot at the Mai Po Nature Reserve,” she explains, “Taiwan is on the migratory path of several important birds, which were key to my understanding of ecology and conservation as a whole system, getting me started on public awareness and involved with policy.”

Creating wetlands

Most of Yam’s work revolves around constructed wetlands, specifically engineered and monitored areas which serve to rehabilitate lost natural wetlands but also address other needs such as ecological methods of purifying waste water. 

Yam’s team is trying to enhance constructed wetlands and their conventional uses for better carbon sequestering, monitoring climate change, aiding wildlife needs, and public ecological education. While using plant and soil bacteria to carry out biochemical processes such as wastewater treatment is not new, monitoring the needs of the different plants, animals, and designed environmental projects with the ultimate goal of being self-sustaining wetland habitats is still a work in progress. 

Sites which are built primarily for wastewater treatment have specific plants to absorb different pollutants and maintain the bioecological sphere, but random factors like the invasion of apple snails from South America can throw this plan into chaos. Trying to be as eco-friendly as possible, scientists design and use plants which do not support the snail life cycle in order to slowly get rid of the problem instead of using chemicals, but all this takes time and close attention.

Fifty or sixty years ago, conservation was not on policy or public radars, and the emphasis on economic development saw many natural wetlands converted for commercial agriculture, industry, and city expansion use in Taiwan, part of the eradication of nearly half of the number of wetlands globally.

Taiwan has more than one hundred constructed wetland sites across the country, thanks to ecological technology advancing to catch up with extensive industrial development. 

As an island with a mountainous center, most of Taiwan’s flat lands suitable for development are along the coast, where natural wetlands are also present. While constructed wetlands cannot yet fully replace natural ones, the government has championed integration of wetland projects and conservation as part of agriculture and city planning initiatives in coastal regions.

Support and protection

The conservation and ecological development Yam’s university lab does, as well as the rising public interest in such efforts, brings an added collaboration with the government, including valuable research funding and serving on planning committees. 

In 2013, work to pass the Wetland Conservation Act finally paid off, making it clear what type of wetlands can be used for development and which must be protected. The balance between industry and environment is evident in the complex division of wetlands for protection, mitigation, and development. 

In most cases, developers seeking to build on wetlands must adhere to a compensation plan to help reduce their ecological impact, which has been successful so far, but will need continuous review and oversight. 

Best of all for Yam, two internationally important sites for black-faced hornbills, highly endangered birds which winter in Taiwan, were officially protected for conservation. 

Currently, she is part of a team developing policy on sediment control and mitigation, “not something that captures the popular imagination, but starting from the bottom is actually important!” 

The traditional focus has been on water quality, but many pollutants sink and bind to the sediment in water bodies, resulting in high accumulations with varying degrees of speed in releasing dangerous chemicals back into the water. 

The unique conditions of the wetlands and the ecological impact on animal species would make them an obvious indicator of the environment’s health, but further research is needed on specific effects of various pollutants on their biology before they can be reliable indicators. 

“In order to understand the environmental condition better, we need to really know what sediment we are dealing with and develop monitoring techniques to restore or control sediment conditions. Most Asian countries still don’t do this, so this is a doubly important step,” Yam says.

Ecological defenses

Flood control is an ongoing priority, so the Taiwanese government has promoted development of stormwater wetlands which stay dry in the dry season and can be used as parks, and which store stormwater in the rainy season. While public policy does sometimes win out over research, especially since constructed wetlands’ wastewater treatment is far cheaper than usual processing systems, the other values of these spaces are also appreciated. 

Multi-function wetlands in Taiwan are far more advanced than in other Asian countries, driven by the public and government’s interest in exploring their function.

Yam mostly works on wetlands which store storm runoff from the central and southern parts of Taiwan year-round and which are not intended for wastewater treatment. 

With better water quality and location, she hopes to make these sites more suitable for bird habitats, encouraged by the growing number of nests spotted. 

This is a particular passion for her, and evidence of how important integrated conservation efforts are in Taiwan. 

“Taipei is highly developed, but this has interfered with the migration path of many bird species, whose natural resting places have been lost or become unusable,” she says, “Many of these species are endangered and already exposed to pollutants elsewhere on their route, so they need the protected wintering and summering sites, which we could give them.”

Increasingly, conservation efforts and academic ecological projects are growing to span countries. 

“Animals move around without passports, and we need to think about their natural range and survival needs as well as larger-scale sustainability policies,” Yam notes. 

She participated in the Securing the Conservation of Biodiversity Across Administrative Levels and Spatial, Temporal, and Ecological Scales (SCALES) project three years ago which focused on collaborative policy and biodiversity management across designated ecosystem scales. 

Yam’s most recent project with the Global Lake network takes her to remote lake mountains in a national park, where the relative protection from pollution makes the lakes more sensitive to environmental change and therefore important indicators of climate change. 

The wetlands’ lower altitude and exposure to environmental stressors make them unreliable indicators of climate change, but comparing the two ecosystems is still a promising field. 

Projects like this draw wide public interest; everyone understands that climate change is happening, but where more summer rain and mudslides can be overlooked, drought and drastic changes in weather patterns are impacting daily life to the point where comprehensive change is welcomed.

One of the great joys of Yam’s work is the interactions with students, scientists, government officials, and the public, which she credits with teaching her every day and developing her research in more advanced, practical ways. 

Yam encourages young scientists to follow their natural curiosity, to think of nature and animals as critical scientific actors. 

“Ecology is just as interdisciplinary as other cutting edge scientific fields, and there’s the added bonus of helping to find the solutions for some of the bigger questions of our time for future generations and our neighborhoods right now,” she urges, “Economic development and the environment aren’t always in conflict, but finding a balance can only be done with academia’s help.”

Dr Rita Yam holds an undergraduate degree in biology and a PhD in River Ecology from the University of Hong Kong. She was a 2005 Croucher Fellow at the Centre for Ecology and Hydrology, and completed a postdoctoral fellowship at the Wallingford Center for Ecology and Hydrology. Dr Yam is currently an Assistant Professor at the Ecology and Conservational Laboratory of the Department of Bioenvironmental Systems Engineering at the National Taiwan University. 

To view Yam’s personal Croucher profile, please click here.