List of Dissertation Abstract (Department of Natural Environment)
NameOhira Atsuko

Supervisor
Nakamori
Taizo

Fatema Umme Matsuda
KanizHiroyuki

Title

Abstract

Taxonomic Studies onThe identity of the generic type species Crossodonthina

Neanuridae (Collembola)nipponica is unclear because the original description lacks
detail and the redescriptions from different localities areinconsistent. In this study, C. nipponica was redescribedbased on specimens collected in the type locality. Also,
Crossodonthina laterisensillata sp. nov. is described fromIriomote Island, Japan.

Effectiveness of Sustainability

We conducted the study focuses on the effectivenessof sustainability indicators in both marine fisheries
such as shrimp fisheries with its bycatch and in marine
aquaculture such as Coho Salmon, Red Sea Bream,
Yellowtail, and Bluefin Tuna aquaculture. To determine
the sustainability of marine fisheries, we usedproductivity susceptibility analysis, which is widely
applicable semi-quantitative ecological risk
assessment tool for data-limited fisheries based on theavailable species-specific biological, and fisheryspecific characteristics. Concurrently, we used simpleindicators to the evaluation of sustainability in datalimited marine aquaculture based on the aquaculture
production, nutrient load produced in aquaculture
farms, and location of the farms in enclosed bays.

Indicators in Shrimp Fisheries
with Bycatch and in AquacultureMatsumoto
TakumiIshikawa
Masahiro

A study on the distribution ofcrustal heat flow in the JapaneseIslands and the thermal structure of
Northeastern Japan

Akutsu
Keiji

OikawaHirokiToward sustainable conservation ofbiodiversity on private land: Acomparative study on institutional
design of conservation agreementswith landowners

This study measured crustal heat flow at wells in Japan toobtain a new dataset of high-density crustal heat flow
uniformly distributed over the land area. The data shows a
low global distribution of crustal heat flow on the frontal
arc side and high on the dorsal arc side of the volcanic
front. Additionally, the study constructed a higher density
and more precise crustal heat flow dataset to clarify thesubsurface heat structure in northeastern Japan. The
obtained spatial distribution of heat flow shows low heatflow on the forearc side, high heat flow along the Ou
Backbone Range, and low heat flow in the plains on theback-arc side. A crustal temperature structure model was
also developed, which shows a good correlation with thelower limit of the seismogenic layer.
Although an agreement-based approach seems practical inprivate land conservation performed by landowners,
public bodies and NGOs, in Japan, related programs or
institutions are scattered across traditional
administrational segments, and besides, areas under some
programs have begun to shrink as the participants drop
the renewal of agreement. In contrast, a long-standing orrecently renovated programs of conservation agreement(covenant) with a variety of support to landowners
including economic incentives are seen in New Zealandand New South Wales (Australia). Through thecomparative analysis, this research draws insights on theimportance of designing sustainability in institutional
establishment as well as management.

Iwachido Yuki

SasakiTakehiro

Local and landscape drivers of plant
diversity and composition in
urban greenspaces

Suzuki Kureha

SasakiTakehiro

Reconsidering the role ofplantations in ecosystem structure,composition, and dynamics towardecosystem-based forest restoration

To mitigate the urbanization effects of landscape factors,
such as habitat fragmentation caused by urbanization, andlocal factors, such as human-induced disturbance, on
biodiversity, it is imperative to comprehend the relative
importance of these factors and address associatedconservation issues. This study investigates plantcommunities in urban greenspaces within the Tokyo
metropolitan area and demonstrates that the relative
importance of each factor varies with urbanization, andthat developing new green spaces to mitigate landscapefactor and new usage of green space to mitigate local
factors are effective conservation strategies. Thesefindings highlight the importance of considering both
local and landscape in the urban biodiversity
conservation.
Restoring forests has recently received considerable
attention. The potential of simple plantations, which arestill one of the major schemes for reforestation activities,
in fostering natural regeneration has not yet been welltested. In this study, I evaluated the potential role ofexisting plantations in contributing to natural forest
restoration in Shiretoko, Japan. Specifically, I assessed
whether naturally regenerating forests can be sustained inplantations from the perspective of forest structure,composition, and dynamics by combining vegetation
inventory, remote sensing, and simulation model. In theshort term, a positive relationship between larchmonoculture plantations and the growth and regenerationof native trees was found, though larch is an alien species
in the study site. The long-term restoration potential ofplantations differed among the combinations of planted
tree species and planting densities. In sum, the study
highlights the importance of evaluating the restoration
potential of plantations, including planted tree species
and planting densities, as well as species-specific traits. It
concludes that managers need to be aware of the contextdependency of plantations of single species or alien
species to make restoration more effective, especially inareas where they have already been established.

Watanabe
Akira

MatsudaHiroyuki

Adaptive management in
population ecology: Cases of
COVID-19 and Japanese sardine(Sardinops melanostictus)

The objective of my dissertation is to use adaptive
management to make reasonable decisions and strategies
for public issues with uncertainty. In particular, the paper
focuses on the control of infectious disease caused by thenovel coronavirus and the fishery management of thePacific stock of Japanese sardine, an important small
pelagic fish stock. The key points in common between thetwo areas are that mathematical models have some power
to deal with highly uncertain problems, that there aredecision-making systems that can adapt to new knowledge
as it becomes available, and that there are systems tomonitor trends in the number of people infected with thevirus and in the abundance of fish stocks.