In this post Associate Editor Akira S Mori discusses the research currently being undertaken in his laboratory to tackle environmental and ecological challenges and how this work can help to inform landscape management and policy in Japan.
There is an increasing recognition of the current environmental and ecological crisis in Japan. The country is the world’s third-largest economy by nominal gross domestic product (GDP). The country historically has a large population in the small land areas of the archipelago, and now has a population of over 120 million. Because of such high population density, landscapes and seascapes in Japan have been historically largely affected by human activities including urbanization, extensive conversion from natural vegetation to plantations, agricultural and aquacultural intensification, and so on. Many environmental issues such as water and air pollution have been substantially improved but there still remain many concerns such as climate warming and biodiversity declines. Ecological consequences resulting from these modern issues have large uncertainty, and people including ecologists are facing difficulties.
Here I introduce ongoing applied ecology studies from our laboratory (Mori Ecology Lab) as an example of how scholars in Japan are tackling environmental and ecological issues. Although the approaches we employ are very diverse (field work, simulation, data synthesis and so on), our lab has a main focus on field-based evidence and application of this knowledge to real-world issues.
One of our main field sites is Shiretoko National Park, which is also registered as a World Natural Heritage Site of United Nations Educational, Scientific and Cultural Organization (UNESCO). This area provides one of the richest northern temperate ecosystems in the world and is an outstanding example of the interaction of marine–terrestrial ecosystems and of extraordinary ecosystem productivity (UNESCO). The area has particular importance for a number of marine and terrestrial species. Some species in Shiretoko are endangered and endemic, such as Blakiston’s fish owl (Ketupa blakistoni) and the Shiretokosumire plant (Viola kitamiana). Unlike Tokyo and other big cities, the number of residents in Shiretoko is not large because of its location situated in the northeast corner of the northernmost island (Hokkaido) in Japan. However, there are still over 7,000 residents in and around the park. Fisheries are the most important industries and have historically affected nature. In terrestrial areas, approximately 90% of the land is still covered with pristine natural vegetation, which extends from the coast to above the tree line in belts graded by altitude.
Shiretoko is now becoming well-known for the potential and importance of biodiversity conservation in northern Japan. However, we still hardly know how such a high level of biodiversity is structured and organized. In 2010, together with many collaborators (our team was diverse also in terms of nationalities), we conducted field research in forests from near-coast to the timberline. The highest peak in Shiretoko is Mt. Rausu with no road access. We hiked up this mountain every single day. At the beginning of the field work, weather was terrible and although it was July, temperature sometimes dropped to sub-zero during rain. Also, Shiretoko is known as the place with the large population of brown bears (people consider it one of the highest densities in the world), which means potential danger exists during field work. However, we continued to collect data and specimens of diverse taxonomic groups spanning plants, animals and fungi. At first we tried to answer the causes of biodiversity organization along the gradient of elevation in this mountain range. Our outcomes were published as peer-reviewed papers in several ecological and biogeographical journals (e.g. Mori et al. 2013 Global Ecology and Biogeography and Hagiwara et al. 2015, Canadian Journal of Microbiology).
In 2015, one important paper was published (Mori et al. 2015, Journal of Biogeography). In this study, we focused on concordance and discordance between taxonomic and functional diversity and distribution of plants, animals and fungi along the elevation gradient. Our first finding was that species composition of these different organism groups changed along elevation, but functional composition did not (i.e. functional redundancy along elevation). In the future, many species are expected to be forced to move up the mountain to respond to climatic warming, very likely leading to community re-assembly. Our results suggest that climate-induced emergence of taxonomically novel communities may have limited influence on critical ecosystem processes supported by functional diversity. In other words, terrestrial biodiversity in Shiretoko may be resilient to climate change. However, there is another serious concern, which has been directly and indirectly caused by humans. Climatic warming (mild winter), land-use change (cropland expansion) and alteration of food-webs (extinction of wolves) have led to over-abundance of Ezo deer (Cervus nippon yesoensis) in Hokkaido. The resultant over-grazing and browsing by this ungulate herbivore are one of the biggest ecological concerns in the region. Using the above diversity dataset, we thus ran a simulation to foresee potential consequences of non-random loss of plant species on functional composition. We found that extensive herbivory by deer may lead to a possible loss of the functional redundancy of communities that we found in the first analysis. The study emphasizes the synergetic influences between different environmental drivers on both responses of biodiversity and functional consequences of the biodiversity responses. Currently, numerous measures are being conducted to regulate population density of deer in Shiretoko. Our team expects our findings will be useful for local stakeholders that are facing this issue in the region.
The next idea that I would like to introduce for Shiretoko is a volunteer-led activity of land protection. Although the majority of terrestrial areas in Shiretoko National Park are relatively untouched, coastal areas were once used for agriculture in the early 20th century, but these areas were abandoned by settlers by the late 1960s. Then, the abandoned areas were threatened by further land conversion. People in the region and other areas in Japan, who were concerned about this situation, started to voluntarily buy the land tenure in order to prevent the coastal areas from further development (like the National Trust in UK). It continued for several decades until the early 21st century, and the land tenure was transferred to the local government. Concurrently, in these lands protected through the national trust movement, various efforts aimed at restoring forests have been implemented, including re-vegetation activity and establishment of fences to prevent over-grazing and browsing by deer. The restoration areas now consist of mosaics of different vegetation types, including monoculture and mixture plantations (Picea, Abies and Larix species) and treeless windswept lands dominated by a dwarf bamboo (Sasa cernua). The latter lands (with no trees) are caused by restoration failure, indicating that the restoration activities for the last several decades have not necessarily been successful. Importantly, one of the principles of the National Trust in Shiretoko is to ask scholars (i.e. ecologists) for restoration plans before implementing some restoration measures. That is, scientific knowledge is key in restoration activities. For this reason, our team started several field studies in the restoration areas, including one that was published earlier this year (Mori et al. 2016, Ecology Letters).
The study demonstrated the importance of soil fungal diversity in the different vegetation types within the restoration areas for sustaining multiple ecosystem functions (multifunctionality), which are essential for promoting tree generation and forest recovery. Our team is still at the beginning of our projects, but we hope to help managers and policymakers in the region to adaptively manage and restore ecosystems.