List of Dissertation Abstract (Department of Natural Environment)
NameSupervisor

Title

Abstract

Aono Minto

Fumito Koike

Behavior of mid-sized urban mammals

There are many boundary fences in urban landscapes, however,their effects on urban mid-sized mammals have not yet studied.
I investigated behaviors by camera traps. Nyctereutes
procyonoides hardly climbed over the fences. On the otherhand, Paguma larvata climbed over the fences most frequently
among detected mammals, and climbed over even above thefence-hole. Procyon lotor and Felis catus were intermediate. P.
lotor climb over the fences after the holes which they passed
through frequently were closed.
The early geological environment of Earth, often considered awater planet, has been extensively studied in the field ofgeosciences, yet its exact origins remain unknown.
Numerous dating, isotopic, and trace element analyses havebeen conducted on a variety of thick ancient zircon and apatite.
Of particular interest is the estimation of the amount of SiO2 in
the host rock, achieved through the Sr and Y concentrations ofapatite in zircons.
An improved method for determining trace elements in microapatite within zircons, utilizing EPMA , was employed to better
understand the origin of apatite in Jack Hills clastic zircons.
Mantle-type zircons with high total rock SiO2 content suggest
the possible existence of a large continent that intersected withthe plume around 3.6 billion years ago.

against boundary fences

SUZUKIYAMAMOTO Sr,Y trace element analysis of apatite

TOSHIYUKISHINJIin zircon using FE-EPMA. -Improved
analytical methods for Hadean microapatite -Suzuki MihoSasaki

Destination-explicit analysis of tourist

This study conducted destination-explicit analysis of Japan's

Takehirosatisfaction and its determinants innational parks to identify factors enhancing visitor satisfaction,

major Japanese national parks

crucial for sustainable tourism. Surveying visitors'
demographics, motivations for visit, and satisfaction levels via
an online questionnaire across three national parks, wecategorized 117 tourist spots and examined their influence on
satisfaction using ordinal logistic regression. Results revealed
significant effects of visitors' socio-demographic attributes,
such as gender, and tourist destinations' protection levels onsatisfaction. This study offers detailed insights into nationalpark visitors and factors shaping their satisfaction, contributing
to a deeper understanding of visitor experiences and aiding in
the promotion of sustainable tourism.

Sekine Sawako

Oikawa Hiroki Associations of flagship species with

The purpose of this paper is to clarify some aspects of theliving things that are symbols of theactual status of living things designated as symbols of local

community: Facts about birds chosengovernments (hereinafter referred to as "symbol species"), andas symbols by local governments into organize and analyze the selection state, selection process,Tokyo and surrounding areas.

and examples of utilization of "birds," one of the symbol
species categories, in local governments in Tokyo andsurrounding areas. We also examined whether symbolic species
have the function of increasing interest in and participation inconservation activities, and discussed the relationship between
local biodiversity conservation and symbolic species.

Takano Yu

SasakiContributions of urban greenspace

This study investigated the relationship between urban green

Takehirotypes to the subjective well-being

space type (parks, street trees, etc.) and the subjective well-before and during COVID-19

being before and during the COVID-19 pandemic. The results
revealed urban green space types that influence the subjective
well-being before and during the COVID-19 pandemic,
respectively. Not merely being green, but the type of urban
green space is also an important factor influencing well-being.

Tekeuchi Rie

SasakiFifty-year dynamics of forest

Some practices are conducted to make secondary forest similar

Takehiro

ecosystem functions following soil-to natural forests, however there are still few studies thatscarification practices: comparing

quantify the long-term recovery process of natural regeneration

natural regeneration and monospecies

and plantation. This study focused on the ecosystem

planting

multifunctionality (EMF) and compared the effects of 50-year
dynamics of EMF. The results showed that EMF of plantation
forest was not similar to that of natural forests, while thenatural regeneration, particularly belowgeound EMF wastended to be similar. It was suggested that further long-term
research is needed to determine whether the vegetation innatural regeneration forest is close to natural forests.

Tanaka ryu

Yamamoto

Experiments on separation andShinji

recovery of very small amounts ofheavy minerals in peridotite using aWilfley table

Naka Minagi

Takehiro

Successional development of soil

Sasakifungal community on a glacierforeland in The High Arctic.

A new heavy mineral separation method using a Wilfley table
was investigated for the purpose of highly efficient separation
and recovery of ultra-trace heavy minerals such as zircon andbaddeleyite in peridotite. In order to determine the optimal flow
rate, vibration frequency, and other parameters, repeatedseparation experiments were conducted using peridotite. The
optimal conditions were as follows: vibration table angle of 7
degrees in the front-back direction and 0.5 degrees in the leftright direction; vibration frequency of 300 strokes/minute;water volume of pipe 1: 11.25 l/m, pipe 2: 10.25 l/m; and grain
size of <50 ㎛. Three zircon particles were successfully
recovered from 400 g of peridotite, a 37.5-fold improvement
over the conventional method.
The importance of below-ground microbes in ecologicalsuccession has become widely accepted in recent years.
Although soil fungi play a vital role in regulating multiple
ecosystem functions such as nutrient cycles, plant growth, andcarbon budget, evidence is still limited for shifts in soil fungal
community structure in the High Arctic. Our study addressed
this knowledge gap by investigating soil fungal communities
undergoing primary succession in a well-vegetated glacierforeland on Ellesmere Island in the Canadian high Arctic. To
assess the fungal succession trajectory, I established two plotsnear the edge of the glacier and five plots on glacier morainesthat differed in time after deglaciation along the Arklio Glacierforeland ecosystem (chronosequence approach). Using DNA
metabarcoding, we assessed the richness of fungal Operational
Taxonomic Units (OTUs) and their dissimilarity. Fungal OTU
richness showed nonlinear variation during primary succession,
with the greatest in the mid-successional stage. These dynamics
occurred regarding the changes in community composition
from the early to later successional stages, driven by changes inthe community assembly process. Especially, it was revealed
that the soil fungal communities were influenced by soil pH
and the plant communities in the late successional stages.
These results indicate that ecosystem development can change
the fungal community structure as well as the community
assembly process.

Nishino Yutaro

Ryoji Wani

The factor of assemblage of Baculites,

Calcareous concretions containing numerous Baculites, aa Crataceous heteromorph ammonite

heteromorph ammonoids, collected from the Upper Cretaceous
Yezo Formation in the Haboro area, Hokkaido, quantitatively
analyzed. The results of this study revealed that (1) thecalcareous concretions were formed at a site not far from thehabitat of Baculitids, and (2) concentrated parts within theconcretions by a single deposition event can be recognized byvertical changes of shell concentrations. Both dead shells ofbaculitids that had settled on the seafloor and the baculitids that
had inhabited around the area were flowed together and buried
as a dense mass.

Hayashi Kaho

Sasaki

Species diversity effects on tree leaf

Leaf litter decomposition is influenced by traits, climate, andTakehirolitter decomposition in a changing

species diversity. However, only a few studies have comparedclimatethese factors. The objective of this study was to clarify how
traits and species diversity affect litter decomposition undervarying environmental conditions. Using the litter-bag method,
we found that the traits had the greatest influence ondecomposition. Among them, the complementarity andselection effects also differed depending on the species
composition and environment, resulting in differences indegradation mechanisms.

Miyakoshi

Hiratsuka

Screening of plant activators derived

Our laboratory has developed a non-destructive evaluation of

MarikoKazuyukifrom natural products.

gene expression induction activity using transgenic Arabidopsis
transfected with a fusion gene of the PR-1a gene promoter, amarker gene in the salicylic acid pathway, and firefly
luciferase, a luminescent gene, using an increase or decrease inluminescence as an indicator. We have developed a highthroughput screening system. Six compounds derived fromnatural products selected by this system were investigated for a
detailed comparative study of gene expression, and for theircontrol effects against pathogens and the presence of growth
inhibition by compound treatment.

Muraoka Seshin

Wani Ryoji

Estimation of life style of

By analyzing

18O of three fossil shells of Desmoceras

desomoceratid ammonoids using

latidorsatum, the seawater temperature of the surrounding areaoxygen isotopic ratios

where they were living at that time was reconstructed. The
estimated seawater temperature of the septa was higher thanthat of the outer shell. This suggests that the septal

18O havebeen affected by changes in the salinity of the extrapallial fluid
during the process of draining cameral fluid from chambers.
One specimen showed

18O lower than the other specimens in

the early growth stages, suggesting that this specimen lived in
an area with higher freshwater inflow.

Moriwaki

Nakamura

Separation and quantitative detection

Tomomasa

Tatsuoof thiol compounds using composite
nanoparticles of iron oxide and gold

QI YULAN

Takehiro

Changes in plant functional traits

Sasakidriven by grazing and climate in
Mongolian grasslands

Glutathione (GSH) is present in the body and has been reported
to be associated with various diseases. Therefore, a highly
sensitive and selective detection technology for GSH isrequired. In this study, we prepared composite nanoparticles ofiron oxide and gold, adsorbed GSH in an analyte sample,
collected it by magnetic separation, and evaluated a system todetect and quantify GSH by MALDI-TOF-MS using theionization ability of the particles.
Aridity plays a significant role in shaping plant communities byserving as a powerful environmental filter, influencing species
presence or absence, as well as vital ecosystem processes likeprimary productivity and nutrient cycling. The combined
effects of increasing aridity and grazing are complex and haveprofound implications for the vulnerability of dryland
ecosystems. Consequently, there is an urgent need tocomprehensively study how ecosystems respond to the aridity
and grazing.
The study of plant functional traits is crucial in understanding
how plants adapt to environmental changes, survive, andreproduce. Research in this area helps us predict and interpret
plant responses to various environmental stresses, thereby
guiding management and practices in fields such as agriculture,
ecology, and biodiversity conservation.
Our study primarily explores the effects of grazing disturbances
and aridity changes on plant functional traits within grassland
ecosystems.The study sites were selected along a gradient ofaridity in Mongolian grasslands. Each site was divided into
grazing and fenced groups.The Fenced groups at each site had
an average establishment duration of thirty years. Regarding
the selection of plant functional traits, we measured andanalyzed four key characteristics: plant height, leaf toughness,
specific leaf area (SLA), and leaf dry matter content (LDMC),
to assess their responses to aridity. Additionally, we also
calculated and analyzed the Functional Diversity Index (FDis)to examine how increasing aridity and grazing disturbances
impact inter-specific diversity. This study reveals thesignificant effects of grazing disturbances and aridity on plant
functional traits within grassland ecosystems.

PHONGSADUANGMANY

Maiko Kagami The Role of Chytrids onChytrid fungi, major organic decomposer in Lake Biwa were

Decomposition of Large Algae

examined how they utilize inedible algae (Staurastrum(Staurastrum dorsidentiferum anddorsidentiferum and Micrasterias hardyi) by using 3 years

Micrasterias hardyi) in Lake Biwa

samples observation and incubation experiment under light anddark conditions. The result showed that Micrasterias was
mainly colonized in the deep layer while Staurastrum wasinfected all layers. Besides, the chytrid performed better underdark condition rather than light condition. In addition, chytrid
grew better in the dark, even without algal cells, indicating thatlight itself inhibited the chytrid growth. Our results suggested
that light affected the chytrids growth, which influenced thematerial decomposition in the deep layers.