This project summarizes the findings of research organized in two parts. The first involved the characterization of changes in the variability of climate that lead to extreme events. The second focused on the predictability of extreme climate on time-scales ranging from short forecast lead-times to long-lead climate predictions exceeding a year. Initial studies focused on three interrelated, yet regionally unique extreme climate phenomena. First, the relationship between increasing greenhouse gas (GHG) emissions and particulate matter (PM) concentration in basin terrain was investigated. Next, we evaluated changes in large-scale atmospheric circulation associated with two climate phenomena at either extreme side of the water cycle--droughts and floods. In the final analysis, an attempt was made to understand the mechanisms that link two North Pacific ENSO precursor patterns to the ENSO cycle.

Philosophiae Doctor - PhD / Wetlands are highly productive systems that act as habitats for a variety of flora and fauna. Despite their ecohydrological significance, wetland ecosystems are under severe threat as a result of environmental changes (e.g. the changing temperature and rainfall), as well as pressure from anthropogenic land use activities (e.g. agriculture, rural-urban development and dam construction). Such changes result in severe disturbances in the hydrology, plant species composition, spatial distribution, productivity and diversity of wetlands, as well as their ability to offer critical ecosystem goods and services. However, wetland degradation varies considerably from place to place, with severe degradation occurring particularly in developing regions, such as sub-Saharan Africa, where Land Use and Land Cover changes impact on wetland ecosystems by affecting the diversity of plant species, productivity, as well as the wetland hydrology.

京都大学 / 0048 / 新制・課程博士 / 博士(農学) / 甲第20816号 / 農博第2256号 / 新制||農||1055(附属図書館) / 学位論文||H30||N5098(農学部図書室) / 京都大学大学院農学研究科森林科学専攻 / (主査)教授 神﨑 護, 教授 北島 薫, 教授 德地 直子 / 学位規則第4条第1項該当 / Doctor of Agricultural Science / Kyoto University / DGAM

京都大学 / 0048 / 新制・課程博士 / 博士(理学) / 甲第20962号 / 理博第4414号 / 新制||理||1634(附属図書館) / 京都大学大学院理学研究科生物科学専攻 / (主査)教授 湯本 貴和, 教授 古市 剛史, 教授 友永 雅己 / 学位規則第4条第1項該当 / Doctor of Science / Kyoto University / DGAM

Forest disturbance occurs on a wide gradient of selectiveness and creates new growth opportunities for adapted species. Across the spectrum of disturbance, anthropogenic disturbance influences community assembly in the Midwest more than other mechanisms but is its role in shaping and maintaining ecosystems is inadequately considered in most discussions on the historic range of variability (HRV). Forest resiliency is threatened by unprecedented agents of ecosystem change such as invasive species and reduced regeneration potential of native species. Historic anthropogenic disturbance largely resulted in forest conditions which commonly contained high value attributes like heterogeneity across habitat types and landscape diversity, yet also produced forests of undesirable traits due to high grading for timber and overgrazing by domesticated stock. In order to maintain historical representative forests and improve the degraded forests, active forest management is necessary to continue historic disturbance patterns and combat new threats. Forest transition theory is used here to describe the impacts of human settlement and development activities on forest ecosystems across the Middle Mississippi River Valley. To date, researchers have identified the need for information related to changes of forest attributes such as species composition and stand structure, improved descriptions of short- and medium-term dynamics within the context of the long-term transition, and the integration of biophysical drivers of forest change through time. In Midwestern U.S.A., forest dynamics were influenced by frequent, low intensity disturbance events that mediate forest composition and stand structure by selecting for disturbance regimes that create oak woodland and interspersed prairies and meadows. The onset of Euro-American settlement was accompanied by detailed land-use records with information related to forest attributes, agricultural activities, and parcel ownership patterns. We aggregated multiple sources of historic forest conditions into a geodatabase in order to document changes over the past 200 years in Elsah Township, Illinois, where the pre-settlement (1820) forest, once dominated by oak and hickory species, has largely shifted to a maple dominated system with a declining oak-hickory component, heavily influenced by an invasive shrub species, bush honeysuckle. Using on ordinary kriging interpolation, forest density was estimated at 8.7 stems per acre on average with a mean basal area of 14.6 square feet per acre prior to settlement. Conservation practices of the early 1900s, including fire suppression and erosion control resulted in changes to forest structure with density increases to 127 trees per acre with a basal area of 175.8 square feet per acre. The high degree of topographic variability near the Mississippi River influenced forest cover changes as slopes with low angles were the first to be converted from forest cover to other land uses (circa 1850). Forest re-initiation occurred in areas with steeper slope due to a lack of human activities. Forest cover declined to the lowest point in 1927 and has been rebounding steadily throughout this century. Of the original 15,252 forested acres, 11.6% remained covered throughout the past 200 years and coincided with slopes with an average of 39.1 degrees. These data can provide a spatially explicit and historically accurate tool to guide land management decisions including restoration treatment, disturbance regime management, and land use preservation activities in similarly heterogeneous environments. Forest communities along the bluffs of the Mississippi River differ in species composition and stand structure associated with specific topographic positions of floodplain, transition talus slope, bluff top, and upland. In order to assess current stand characteristics and ecosystem trajectory, we measured all woody stems in 316 fixed radius plots (79 plots per topographic position) with a plot area of 25 m2. Alpha (defined as within system diversity) and Beta (defined as between system diversity) diversity and diameter distributions were determined for seedling, shrub layer, and overstory stems. Stem density increased from 21.4 stems ha-1 in 1820 to 613 stems ha-1 in 1936 followed by reduction to 314 stems ha-1 in 2017. Average stand diameter decreased from 40.9 cm in 1820 to 25.3 cm in 2017 (for upland stems greater than 7.5 cm) while basal area increased from 3.3 m2 ha-1 in 1820 to 40.4 m2 ha-1 in 2017. Alpha diversity was highest in the upland overstory and in the river island shrub layer. Beta diversity in the overstory was highest (0.67) between the bluff and the upland while lowest (0.08) between the bluff and the river island. Importantly, mesophytic species are no longer restricted to watercourses and valleys as reported in historical accounts and confirmed by the spatial analysis of original witness tree records. Currently, bush honeysuckle, an invasive species, dominates the shrub layer on most non-hydric sites of the talus slope, upland, and particularly across the bluff top where it is an indicator. Across all forest sites in the study, we found evidence of a community shift to less diversity and more mesophytic species over the past 80 years. Hill prairie vegetation on the limestone bluffs of the central Mississippi River Valley represents a significant portion of the remaining prairie, savanna, and woodland systems of the Midwest and should be appropriately managed with prescribed fire and woody stem reduction efforts. We examined the structure, composition, and temporal community patterns of the forest-prairie gradient by employing hierarchical cluster analysis and non-metric multi-dimensional scaling in combination with indicator species analysis and dendrochronological methods. Results suggest that four general community types exist across the forest-prairie gradient: Group 1 consists of the woodland community structure with significant indicator values for the density of Juniperus virginiana (indicator value 58.4, p = 0.0002), Carya glabra (45, 0.0022), Quercus stellata (23.7, 0.0424), and Lonicera maackii (74.2, 0.0002) and a high basal area (BA) of J. virgniana (21.4, 0.0276) and L. maackii (47.9, 0.0054). The first year of L. maackii presence was 1964 with the primary wave of invasion beginning around 1990. Group 2 contains bare soil coverage in the subplot (40.4, 0.0002) as the one indicator at a significant level. The species with the highest BA in Group 2 include Acer saccharum (9.08 m2 ha-1), Q. velutina (5.89 m2 ha-1), and Q. muehlenbergii (5.32 m2 ha-1). Group 3 typifies the hill prairie community with the sole indicator of grass coverage in the subplots (39.7, 0.0196). Group 4 represents the stage of forest development following the cessation of disturbance events and the trajectory advancing towards a mesophytic forest and contains 14 significant indicators.

Communication is a behavioral strategy used by species in the competition for survival and reproduction. Animals produce signals that are sent to receivers and occasionally transmit information that can be beneficial in a variety of contexts including avoiding predators, locating food resources, and maintaining the pair bond between partners. Researchers are interested in if auditory signals are variable and if the variability is biologically meaningful to receivers. Some species, such as siamang, sing duets as their form of acoustic communication and these duets have been studied for a variety of purposes such as investigating their structure, variability, and functionality. Siamang are a species of gibbon that combine a finite number of call units into structurally complex sequences in rule-governed ways, hereby conveying different contextual situations. Some wild gibbon species have demonstrated variation in the temporal structure of their duets and the distinctiveness in acoustic timing is unique enough for researchers to distinguish among individuals and groups based on their duet contributions. The process of coordinating and producing a uniquely timed duet could function in relation to the formation and maintenance of the pair bond. This dissertation analyzed the temporal variation and call order of wild siamang (Symphalangus syndactylus) duets that are comprised of four distinct sequences comprised of several note types. Previous research has provided detailed descriptions of captive siamang duets that include category descriptions of four call types: grunting, introduction, interlude, and great call. While these descriptions provide a general understanding of the structure of siamang duets, they can be confusing and difficult to study empirically due to their arbitrary nature. For instance, the siamang great call has been described as occurring in over 30 variants and in stable, or typical, and unstable, or atypical forms. The stable or typical form of the great call has been described to occur only after the male’s first bitonal scream. This previous research did not measure the timing of sequences through entire duets or conduct individual note analyses. Also, the most detailed investigations of siamang duets were conducted with captive animals and therefore wild siamang duets have not been quantitatively analyzed. This dissertation research measures the temporal variation of wild siamang duet call types, and the call order of individual notes in the US-II phrase. The findings will provide a more objective description of the siamang duet as well as determine if it has a more stereotyped or flexible nature. Also, in the wake of globalization, duets and other behaviors (such as travel) could be sensitive to anthropogenic disturbances. So, I am interested in how wild siamang might be impacted by human presence. The three main objectives of this dissertation are: 1) document the temporal variation in the call types of wild siamang; 2) document variation in the call order of wild siamang US-II phrases; and 3) document how wild siamang travel is impacted by anthropogenic noise. The study was conducted at 4 remote field sites in northern Sumatra, Indonesia from August 2017 through May 2018. With the assistance of a research team, I recorded acoustic and behavioral data from 10 siamang groups and two individual females. I collected acoustic data using a combination of autonomous recording units and handheld recording devices while following the study subjects on foot. I marked GPS points during behavioral scans and conducted experimentally induced noise playback experiments. I analyzed the audio data with the software program Raven Pro 1.6 and spectrograms were produced with a 512-point (11.6 ms) Hann window (3 dB bandwidth = 135 Hz), with 50% overlap and a 512-point DFT, yielding time and frequency measurement precision of 2.9 ms and 43.1 Hz. I conducted statistical testing in R Studio Version 1.3.959 in conjunction with the statistics lab at Southern Illinois University. In Chapter 3, I performed multilevel regression analysis in the form of a Generalized Linear Mixed Model (GLMM) in order to investigate temporal variation the time spent singing call types (grunting, introduction, interlude, and great call) accounting for differences between songs, groups, and field sites. I used a Bayesian hierarchical model to avoid calculating estimates using data with repeated and imbalanced sampling, and explicitly model variation within individuals, between songs, between groups, and field sites. In Chapter 4, I used the Levenshtein Distance (LD) method for investigating structural variation in the call order of US-II phrases in the siamang duet. The LD method is a quantitative technique for measuring the similarity of sequences and to quantify the differences between strings of data. In Chapter 5, I used the Friedman test to compare the means of distances traveled in 5-minute intervals in the following conditions: pre-playback, cicada (control), traffic, jackhammer, and music. I used post hoc tests with Bonferroni correction to analyze the pairwise comparisons of the five experimental conditions. Overall, the results suggest support of previous studies on the variability of the gibbon duet and animal travel in response to noise. In Chapter 3, I found some temporal variation in call types to exist at all levels of the modeling but only statistically significant when comparing the field sites of Ketambe and Kutapanjang. Relating to the functionality of total call duration, I did not find significant differences in the behavioral categories before or after any of the calls regardless of their total duration. In Chapter 4, I found US-II phrases are not as stereotyped as previous descriptions have suggested. The mean LD distances were higher than those compared by other duetting primates. Also, the results from one-way ANOVA and Games-Howell Post Hoc Testing showed significant mean differences between groups. In Chapter 5, I found siamang are impacted by noise as they traveled further after the anthropogenic noise playback experiments compared to pre-playback travel. However, the pairwise comparisons were not statistically significant and therefore I could not determine which noise condition caused the change in travel distance. Collectively, the results of this dissertation suggest that there is considerable variability in both wild siamang call types and call order in a previously described stereotyped phrase, and that wild siamang travel away is impacted by introduced anthropogenic noise. What this contributes to the field of vocalization studies is further support that precise measurement of song parameters gives a better understanding of song structure than somewhat arbitrary written descriptions. It is important to have descriptions of notes produced in songs, but to understand how those notes relate to each other, an individual note analysis and rigorous statistical methodology is necessary. The variation found in this dissertation could be due to the unique siamang response to their partner’s timing in the process of forming the pair bond. But as the siamang duet is thought to have multiple functions, the temporal variation could also be transmitting other information such as individual and group identity while functioning in territorial defense. In addition, anthropogenic noise caused the animals to change their travel behavior and this suggests it could be harmful if faced on a regular basis. Anthropogenic noise can be detrimental if it occurs in home ranges of species that are territorial and facing shrinking habitats due to continued human encroachment. In order to understand if these findings are biologically meaningful and to have firmer conclusions, future long-term studies will need a larger data set over longer periods of time. It is also important to have a larger data set and compare more siamang groups that live in various noise levels and measure variables such as caloric intake, daily travel, copulations, and number of offspring.

Conducting species inventories is important to provide baseline information essential for management and conservation. Furthermore, understanding the effects of anthropogenic and environmental factors on species richness and occurrence are crucial to conserve species. Aldesa Valley lies in the Tabuk Region of Saudi Arabia, and because of the presence of permanent water and vegetation, is thought to contain high biodiversity. I estimated avian species richness and occurrence in Aldesa Valley during May 10–August 10 in 2014 and 2015 to detect bird species richness and occurrence. I used generalized linear models and occupancy models for six commonly detected bird species. I recorded 24 bird species, and found that species richness and occupancy was affected by numerous anthropogenic and environmental factors that influenced species detection and presence. I encourage more biological inventories to further document species occurrences and facilitate conservation of the unique species assemblages in Aldesa Valley.

No description available.

An investigation to assess the anthropogenic pollutant loads, transport and impact on shallow groundwater in one of Kampala’s peri-urban areas (Bwaise III Parish) was undertaken. Bwaise III is a densely populated informal settlement with a high water table (<1.5 m) and inadequate basic social services infrastructure (e.g, sanitation, safe water supply, roads, etc). Field surveys were undertaken to identify, locate and quantify various pollutant sources. Information on the usability and operational aspects of the excreta and solid waste management systems was obtained from consultations with the residents. Water from installed monitoring wells and one operational protected spring and wastewater (sullage) characteristics (quality, discharges for drains and spring, water levels for the wells) as well as soil characteristics (soil stratigraphy, physical and chemical) were determined through field and laboratory measurements. Laboratory batch experiments were undertaken to estimate phosphorus sorption potential of the soils. The results reveal that excreta disposal systems, solid waste and sullage are the major contributors to shallow groundwater contamination. High contaminant loads from these sources accumulate within the area resulting in widespread contamination. The water table responds rapidly to short rains (48hr) due to the pervious and shallow (<1 m) vadose zone, which consists of mostly organic fill material. Rapid water quality deterioration (increased thermotolerant coliforms, organic content in the form of total kjedahl nitrogen, phosphorus) following rains potentially follows from leaching, desorption and macropore flow. Spatial variation of the water quality in the area is largely related to anthropogenic activities within the vicinity of the well sources. Animal rearing, solid waste dumps and latrines are seen to result in increased localised microbial and organic content during the rains. The spring discharge with high nitrate levels does not respond to short rains suggesting that this source is fed by regional baseflow. The corresponding high microbial contamination in this case is a result of observed poor maintenance of the protection structure leading to direct ingress of contaminated surface runoff. Natural attenuation of contaminants is very limited. Estimated bacteria die-off rates are very low, about 0.01hr-1, suggesting a high risk for microbial contamination. The soils still have potential to retain additional phosphorus, whose sorption is largely a function of iron, available phosphorus and moisture content of the soils. This is also seen with the model results in which the phosphorus contaminant plume sticks to the surface irrespective of the rainfall infiltration rates. Simulation results show that continuous heavy intense rains (> 0.25mm/min) result in rapid flooding occurring within 1hr to 2 days. With lower rains, the water table does not rise to the surface, and no flooding takes place. Protection of the shallow groundwater in the area requires socio-technical measures targeting reduction of pollutant loads within the area as well as a wider spring catchment. Re-protection of the spring, coupled with awareness creation, should be immediately addressed so as to reduce microbial contamination. Community participation in solidwaste management should be encouraged. Resource recovery systems such as composting of the mostly organic waste and use of ecological sanitation toilet systems should be piloted in the area. Successful operation of the systems however depends on continuous sensitisation of the communities. / QC 20101207

Widely regarded as a keystone species and ecosystem engineer, the eastern oyster Crassostrea virginica plays a vital role in estuarine environments. Complex, three-dimensional oyster reefs act as havens for biodiversity and contribute to ecological processes. Recently, concern for this resource has arisen in Mosquito Lagoon, Florida, the southernmost limit along the Atlantic coast for undisturbed, intertidal reefs of C. virginica. Since the 1990s, intense recreational boating activity has caused atypical dead margins (mounds of disarticulated shells) to emerge on the seaward edges of oyster reefs located along major navigational channels. Once dead margins are formed, little is known about their influence on biotic composition and interactions on oyster reefs. This study focused on the affect of dead margins on: (1) mobile species biodiversity and distribution, (2) reef architecture, and (3) the affect of structural variables on predation of juvenile oysters. To determine if dead margins influenced the biodiversity of mobile species on oyster reefs, lift nets (1 m2) were deployed within Mosquito Lagoon for one year (June 2004 - June 2005). These nets (5/site) were deployed on the back-reef areas of six reefs (3 reference reefs and 3 reefs containing dead margins). To simulate reef habitat, one and a half liters of live oysters were placed within each net. Lift nets were checked monthly and surveyed for all mobile species. The resulting data were assimilated into a species inventory containing 65 species of fishes, mollusks, crustaceans, worms, and echinoderms. The two most abundant species present on reefs in Mosquito Lagoon were the big-claw snapping shrimp Alpheus heterochaelis, a filter-feeder, and the flat-back mud crab Eurypanopeus herbstii, a predator of oyster spat. Contrary to expections, analyses of community metrics showed that dead margins did not significantly affect the biodiversity of back-reef areas on oyster reefs. Modified lift nets (0.25 m2) were placed on six different oyster reefs (3 reference reefs and 3 containing dead margins) to test if dead margins affected the distribution of mobile species inhabiting oyster reefs. Nine nets were arranged to cover three separate areas of each reef: the fore-reef (3 nets), mid-reef (3 nets), and back-reef (3 nets). Half a liter of oyster shells were placed inside each net. These nets were checked weekly, for five weeks and species richness, density, and biomass were recorded. Analyses revealed that all community metrics were significantly higher on reference reefs than reefs affected with dead margins. Further, a significant drop in all three metrics was seen on the mid-reef area of affected reefs. The absence of species on this area is hypothesized to be due to a lack of water, shade, and habitat complexity. To document architectural differences, two types of transects were run along five reference reefs and five reefs with dead margins. First, quadrat transects determined the percent of live oysters, the percent of shell clusters, topographic complexity (using chain links), and the angle of shells on each reef type. Transect lines were stretched parallel to the water line and covered all three reef areas (fore-reef, mid-reef, and back-reef). The results showed reference reefs to have approximately four-fold more live oysters, approximately twice as many shell clusters, and significantly greater topographic complexity. Numbers of live oysters and shell clusters were greater on the fore-reef and back-reef areas of both reef types. Second, laser transects were used to record reef profiles and the slope of fore-reef areas. Transect lines were stretched perpendicular to the water line and every 20 cm the distance between the lagoon bottom and reef top was measured. Vertical reef profiles and fore-reef slopes were significantly different between reference reefs and reefs with dead margins. Dead margins compressed reef widths, increased center peaks, and increased slopes on the fore-reef area by two-fold. Lastly, field experiments were conducted to determine the affect of dead margins on the vulnerability of oyster spat to predation. Structural variables (e.g. shell orientation, single versus shell clusters, reef slope) were manipulated and effects on oyster mortality were observed. Three predators were tested: the blue crab Callinectes sapidus, the common mud crab Panopeus herbstii, and the Atlantic oyster drill Urosalpinx cinerea. Structural variables did not have a significant influence on oyster mortality; however, a significant difference was established between predators. Panopeus herbstii consumed the most juvenile oysters, followed by U. cinerea and then C. sapidus. Together, these findings document ecological implications of dead margins on C. virginica reefs and reinforce the urgent need for enhanced regulations and restoration. If the intensity of recreational boating remains unregulated, dead margins will continue to increase. Thus, in order to maintain the diversity and productivity of Mosquito Lagoon, it is crucial to fully understand how dead margins alter the biogenic habitat and biotic communities of oyster reefs.