Biodiversity

Homepage: http://www.nies.go.jp/biodiversity/index-e.html

Assessing wildlife habitats on a large spatial scale
The possibility of extinction of wildlife species is increasing as individual habitats shrink due to human activities that cause their destruction and fragmentation. However, this is difficult to show objectively and accurately. The main reasons for this are that the impacts of human activities continue to expand, and the distribution and abundance of wildlife species change rapidly. As a result, the data collection of the distribution of species requires an enormous amount of time and effort. One measure to overcome this difficulty is to infer the areas with high suitability for certain species to inhabit (i.e., the potential habitat). Such inferences are based on ecological information about what resources (such as food, refuge, nesting areas, etc.) are needed by a given species, and where those resources exist. This is accomplished by using technology such as GIS to identify suitable habitat. Based on such ecological and geographical information, we are developing a methodology to indicate the locations where habitats are suitable or unsuitable for certain wildlife species on maps. The aerial photograph below shows the distribution of the great reed warbler and the reed beds that serve as its habitat surrounding Lake Kasumigaura in Japan.

Around Lake Kasumigaura there are reed beds that are suitable (blue dots) and not so suitable (red dots) for breeding of the Great Reed Warbler. The size of the dots shown represents relative size of the reed beds.

It is not just enough to conserve the distribution of natural organisms on a species-by-species basis. In many cases, the genetic differences exist even within the same species. In order to maintain genetic diversity within a species, it is essential to clarify the features of local populations and to develop conservation measures that take the geographical range of each population in account. However, because it is impossible to study all species, we are trying to identify the common range boundaries shared by many species.

Probing the Roles of a Mosaic of Watershed Landscapes
Many naturally flowing rivers once meandered freely, alternating between shallow and deep sections, allowing many river fish and shellfish to flourish. As the river banks stabilized, trees grew along the water's edge and this through a variety of functions enriched the biotic life of the river and the surrounding area. The same could be said about lakeshores and the aquatic plant life growing along them. The geographical features (topography and vegetation) making up watershed landscapes are distributed in complex ways in nature, complexity of the landscape features is expected to enhance the diversity of aquatic ecosystem. This project analyses the complexity of the landscape in maintaining the diversity in the aquatic ecosystem. Based on the outcomes of this research, we are aiming to estimate the biological diversity and status of biota, and utilize the data in watershed management using GIS.

The Sarufutsu River (Soya, Hokkaido) flowing through a natural forest. Many natural rivers in Japan once meandered like this.

Simulation and theoretical studies on the mechanisms of coexistence and extinction of species
Field research is essential for the studies on the mechanism of coexistence and extinction of plant and animal species under natural conditions, but it is time-consuming. On the other hand, experimental studies are often not practical. Simulation studies using computer models are one of the alternatives.
We are developing individual-based models of plant community to reproduce the dynamics of plant populations. Factors affecting the extinction and coexistence of the species are surveyed through experiments using virtual systems of plant communities. Among the possible factors are the size and the degree of fragmentation of the area, dispersion ability of the plants, their mode of sexual reproduction, and genetic properties of the plants.

We are developing methods to assess the risk of extinction in plant communities. The method will be used for the design of nature conservation area. We are also working on the evolutionary processes of the current biodiversity pattern on the earth. The main tool of the study is a virtual food web system, which spontaneously evolves through the random mutation of the component species. The study is expected to give light to the understanding of the origin of the present-day biodiversity.

Schematic diagram of the tree regeneration process of and individual-based forest model. The forest area is represented by a lattice. Each small area of the lattice is occupied by at most a tree, not by two or more. When a tree dies, the remaining vacant area is filled in by a tree sprouted from one of the seeds dispersed to the area from neighboring trees.

Investigating the Ecological Impacts of Invasive Species
One of the threats to biodiversity is the biological invasion that occurs when a species alien to an area is introduced and is established in the environment. Changes inevitably happen in interrelations between the species when an exotic species is established, and the ecosystem is irreversibly modified. Although the colonization of migrant species is a common phenomenon in the history of organisms, recently there has been an increase in concern about the loss of biodiversity caused by the alien species introduced by humans. Many plants and animals are imported into Japan without any regulation (with the exception of certain pests); as a result, the invasive species are increasingly becoming the threats to biodiversity. Therefore, NIES is conducting a case study of the impacts on native ecosystems (in particular, plant species that depend on bee pollination and Japanese native bumblebees resulting from the import of the European bumblebees for agricultural use).

World-widely exported European bumblebees Bombus terresi. Their establishment in the wild may lead the to the extinction of native bee populations, the hybridization between alien and native species, and the spread of accompanying parasitic or infective organisms into the wild.

Assessing the Ecosystem Impacts of Genetically Modified Organisms
In order to develop methodologies to assess ecosystem impacts of genetically modified organisms, we are involved in reconsidering the existing techniques and developing novel methods to test their safety. For example, when conducting bioremediation using microbes to clean the environment, it is critical to determine the changes in the indigenous microbe populations as well as the behavior of the introduced microbes. We have long relied on a culture method to analyze microbe populations in nature; however, with this method, only a small proportion of microbes (less than one percent) can be analyzed. Therefore, using the PCR and other microbiological methods, we are trying to analyze the behaviors of more microbes in the environment.

In recent years, the cultivation of genetically modified plants has come into question. There are two key issues-the safety of genetically modified plants in food, and the ecological impacts of modified plants. The target of the research project is the latter issue. There are three types of impacts envisioned: the escape of modified plants, the transfer or dispersal of modified genes to closely related species, and toxicity of the products using modified species. It is important to properly assess whether modified genes are capable of dispersal into the natural world. For this objective, we have created modified plants with an introduced gene (marker gene) that changes the shape of its leaves, and are developing a new assessment method that uses the shape of the leaves as an indicator.

The plant on the left is the natural type of Arabidopsis thaliana. On the right is a genetically modified plant with the shape of the leaf changed through the introduction of a homeobox gene. This leaf can be used in the study the dispersal of modified genes.