The World at WU

Sounding out Diversity: Exploring the Realm of Acoustic Diversity with Thailand’s One and Only Behavioral Ecologist


       Counting the number of students in one class is one thing but documenting the flora and fauna in a national park can be an arduous task. One conventional, yet intrusive approach to tackling this task involves sending in specialized troops and manually recording species diversity and its abundance. However, saving time, energy and human resources, Assoc. Prof. Dr. Mullica Jaroensutasinee, behavioral ecologist and dean of School of Science, and her team have championed technology-enabled tracking through “listening”.

Biodiversity index matters

    “In the past or even currently, when you go data collecting on biodiversity at a particular site, all the animals run away, so your best bet is to estimate the biodiversity index through their feces and foot prints. Now, we are replacing a conventional method with a sound recording machine,” explained Assoc. Prof. Dr. Mullica. 

    Measuring the biodiversity index, according to Assoc. Prof. Dr. Mullica, has never been just about making a record. The data collected illustrates the conditions in the wild alerting ecologists to any emergency or defects so that they can proceed to take proper actions in a timely manner such as food imbalance, food deficiency or even extinction of the endangered species. 


    Assoc. Prof. Dr. Mullica said, “One example are little short-lived insects. Small as they are, their abundance actually determines balance in a forest affecting the phenology of plants and animals. Parental birds are cleverly timing egg hatching to synchronize with its prey (insects). So their chicks will have plenty of insects to munch on. If that particular year, let say, insects come out late in the breeding season, there would not be enough food to feed their chicks. With little to quench their hunger, the chicks will instinctively turn to one another to survive and the mother birds will not intervene. Eventually, only one of the three chicks shall come out a winner and live on”.

    Assoc. Prof. Dr. Mullica also talked about her research project on using soundscape technology to gain an insight into biodiversity in relation to STEM education, regarded as the future education.

STEM Education

 Assoc. Prof. Dr. Mullica Jaroensutasinee, behavioral ecologist and Dean of School of Science  

    STEM Education integrates Science, Technology, Engineering and Mathematics, and aims to add a sense of creativity, design and systematic thinking into education. This is to emphasize an integration of STEM practices into any aspect of life. 
Assoc. Prof. Dr. Mullica pointed out some examples, “STEM includes the Internet of Things (IOT), PM 2.5 Sensors, Smart Farming, Big data, Artificial Intelligence (AI), and data visualization. Smart Farming allows you to automatically irrigate your crops as they needed using real-time data from soil sensors and IoT. Farmers can control irrigation system using app on their smart phone anytime anywhere. STEM can be applied to all fields including biodiversity in a forest.”


New Era of Biodiversity Index Measurement 

      Turning to ecology, Assoc. Prof. Dr. Mullica illustrated the outcome of mixing technologies in the area of soundscape ecology which questions how diverse a habitat is and compares habitats between seasons in her project “Temporal Change in Acoustic Diversity in a Parah Forest, Thailand”. Soundscape ecology connects ecologists to animal communication, climate change and anthropogenic effects – regarding migration deeper into the forest in response to man-made noises such as airplanes, cars and air conditioners.

      Assoc. Prof. Dr. Mullica described how the process has been traditionally conducted in comparison with the integrated technology-enabled method. 
“Traditionally, tapping into the area of diversity demands lots of human resources. Simply put, wanting to learn more about life in the wild, you had no choice but to dispatch a crew of experts to the area for data collection. That means quite an investment and risk to take,” said Assoc. Prof. Dr. Mullica. 

   With sustained use of the conventional method, more accuracy, precision of data as well as timely process brings in acoustic diversity enabling ecologists to identify the types of wild animals living in the area, how abundance they are and even what time they are out for feeding, singing, fighting. As for the “Temporal Change in Acoustic Diversity at Parah Forest, Thailand” project, Assoc. Prof. Dr. Mullica began by describing “Parah”.


Into the Wood: Temporal Change in Acoustic Diversity in a Parah Forest

     Parah are tropical fruit-bearing trees whose seeds are made into snacks typically sold at a local market. However, this type of tree only bears fruits once a year but in an extremely large volume as a precaution against stabilizing the habit of faithful Parah seed eaters. In addition, without cracks on the seed’s shell, water cannot seep into the seed which means no germination. 

   “Imagine that I were the tree” said Assoc. Prof. Dr. Mullica. “If I produced Parah seeds all year round, none of the seeds would get a chance to germinate and grow becoming big trees due to the need for specialist seed preditors stationed around, especially yellow spiny rats” explained Assoc. Prof. Dr. Mullica. On the other hand, dropping a large number of fruits once a year, the tree will have more fruits left uneaten.

The study looks into the temporal and seasonal Acoustic Diversity Index (ADI) variations between (December) and dry seasons (January, February, March) at a Parah forest in Khao Nan National Park.        

   The team went into the forest and attached autonomous sound recorders which automatically kick into a 5-minute recording mode every 30 minutes. Using the Acoustic Diversity Index (ADI), the team divided the spectrograms into bins (default 10, each one of 1000 Hz) and took a proportion of the signals in each bin above a threshold (default-50 dBFS). The results suggest that the diversity of the animals seems to be larger in the dry season. The patterns in ADI observed in a 24 hour-cycle also suggest niche partitioning revealing the types of animals out for feeding during the particular hours.

    “Niche partitioning simply means use of the exact same area in different hours by different types of animals. For example, chevrotains will roam the area for food only at 6 am and 6 pm, in order to avoid being eaten by predators while rats will be out only at night. 



You can never do it alone.


Acoustic Biodiversity Index (ABI)

      Despite the extensive role of STEM in education, many national parks still conform to the conventional method. As a result, it is essential that Thai universities offering programs in national park management instill a fundamental understanding of the use of STEM in introducing a non-intrusive method to biodiversity exploration posing zero harm to the animals and increasing chance to obtain more accurate data. Besides familiarity with the original method, forging collaboration to form multidisciplinary crews also dictates success of projects. This is largely because of the extensive volume of data collected, coupled with analysis of big data. 

“One video recording will need to be continuously monitored in detail. The people in charge of monitoring must be constantly attuned to details as to when the specified animals come out, for how long and at what periods, they do. Each spectrum of these details must be thoroughly noted as a live statistical record,” said Assoc. Prof. Dr. Mullica. 

The future of ecology has never been more exciting. 

Article by Nootchanat Sukkaew 

Division of Corporate Communication