Shigeo YACHI

Welcome to Shigeo YACHI's Lab

Contacts

Affiliation	Center for Ecological Research, Kyoto University
E-mail	yachi [at] ecology.kyoto-u.ac.jp
Postal address	Hirano 2-509-3, Otsu 520-2113, Japan

Outline of my research

My specialty is theoretical ecology .

Using theoretical thinking and mathematical models, I have challenged the mystery of various ecological phenomena occurring in the Earth's ecosystem, such as population dynamics of organisms and infectious diseases, coexistence / co-evolution among different species, relationships of biodiversity and ecosystems, methods of ecological restoration, interactions between ecosystems and humans.

In theoretical ecology, we widely analyze phenomena and hypotheses related to ecology/evolution in models using mathematical expressions ("Modeling"). Understanding the phenomenon will be dramatically enhanced in the course of analyzing while rethinking and thinking about modeling the essence of the phenomenon that you want to understand as one model. The deeper understanding through modeling leads to new ideas and working hypotheses of experiments and field studies, creating new theoretical issues, which is a strength and pleasure of theoretical ecology!

(1) Elucidation of the mystery of the global ecosystem

After life was born to the earth about 4 billion years ago, the current global ecosystem was created through various ecological and evolution processes. But what kind of world is this global ecosystem as a whole? In other words, what is the world of earth-type life developed on the planet Earth? What kind of features does our Earth ecosystem have?
I think that answering these questions is one of the major goals of modern ecology.

(2) Management of watershed-scale ecosystem

This research is working on the theme of Global environmental studies.

It is only 100,000 years after the birth of new generation human beings in the global ecosystem, but humans have dramatically changed the global ecosystem. It is said that it is now necessary for us to greatly change the structure of our society in order for humans to live sustainably on the planet Earth. But how is it possible?

In addressing this problem, focusing on watershed management is one key.
The catchment basin is not only a unit of flood control and water utilization closely related to human life, it is a natural unit of management space to preserve and revitalize the ecology of rivers and lakes. I believe that creating watershed management mechanisms that can coexist with communities and basin ecosystems will also help solve global scale environmental problems.

My research contents are the accumulation of concrete phenomena and tasks with interest and involvement from time to time. But through solving mysteries, I would like to approach the whole picture of the Earth's ecosystem on which I was born and have benn living.

To those considering a master's, doctoral, or postdoctoral position in my lab

I'm sorry. My lab is currently not recruiting master's or doctoral students or accepting postdoctoral researchers. The reason is that I plan to retire at the end of March 2027 and will no longer be able to provide sufficient guidance.
Especially for those wishing to study abroad from overseas, there are many labs in Japan where you can study theoretical ecology (or mathematical ecology). I hope you will find a lab that suits you.

Update

Updated on 28th November, 2025