Changes in vegetation and flora of abandoned paddy terraces in responses to drawdown

In order to assess the impacts of drawdown for land-use change on a Sphagnum-marsh, we compared the vegetation and flora of the wetland before and after the drawdown with focusing on the population of Sphagnum palustre L. Remarkable changes in the coverage of S. palustre and the major vegetational components of the wetland were observed. The coverage of S. palustre markedly decreased by about 75% (from approx. 247 m2 in 2011 to approx. 62 m2 in 2015) after the drawdown. Tree species such as Salix spp. extended (from about 70% to about 83% in the total coverage of the wetland), whereas herbaceous species shrunk after the drawdown. Upland-inhabiting species such as obligate plants for uplands (OBU) increased, whereas wetland-inhabiting species such as facultative plants for wetlands (FACW) and OBW decreased in terms of vegetational coverage. The total number of plant species decreased from 70 species to 62 species after the drawdown, including the disappearance of some wetland-inhabiting species from the wetland. We suggest that the attention for further studies on the abandoned paddy terraces (APTs) and effort for the management and conservation of APTs and APT-inhabiting species that are vulnerable to human-induced disturbances have to be paid more.This research was supported by the National Research Foundation of Korea (NRF) funded by the Ministry of Education (NRF-2015R1D1A1A01057373) and by the Korea government (MSIT) (NRF-2018R1A2B2002267)

Relationship between early development of plant community and environmental condition in abandoned paddy terraces at mountainous valleys in Korea

In Korea, many paddy fields in mountainous area have been abandoned because of their low accessibility and rice priceand the abandoned paddy terraces have changed into natural lentic wetlands. To understand the relationship betweencharacteristics of environmental conditions and early development of plant community in abandoned paddy terraces,we investigated at four well-maintained abandoned paddy terraces in 3 different climatic zones in Korea. Soil texture ofabandoned paddy terraces was mostly kinds of loam and electric conductivity of soil was also similar among abandonedpaddy terraces. On the other hand, contents of nitrogen, phosphorus, potassium, sodium, magnesium, and calcium insoil were relatively low and significantly different among abandoned paddy terraces. Water depth was different withinsites and inter-sites. Although environmental conditions including climate, soil condition and water depth were differentamong abandoned paddy terraces, the compositions of plant communities were relatively similar in all abandonedpaddy terraces. 55 dominant taxa out of 141 recorded species were commonly recorded over sites and they were mostlyperennial obligate wetland plants and facultative wetland plants. 8 taxa out of 55 dominant taxa were occurred at allabandoned paddy terraces with over 10% coverage. Several site-specific species were occurred at site, which have somearea with deep water level. This result indicates that early development of plant community in abandoned paddy terracesof similar water regime is similar in the entire area of Korea even though environmental conditions such as climate, biogeographichistory and soil are different.upported by the Center for Aquatic Ecosystem Restoration(CAER) of the Eco-STAR project from the Ministry of Environment (MOE), Republic of Korea (EW33-08-12) and Korea Ministry of Environment as The Eco-Innovation project (416-111-010) and Brain Korea 21.OAIID:oai:osos.snu.ac.kr:snu2013-01/102/0000026049/6SEQ:6PERF_CD:SNU2013-01EVAL_ITEM_CD:102USER_ID:0000026049ADJUST_YN:NEMP_ID:A075900DEPT_CD:719CITE_RATE:0FILENAME:2013jecoenv36(2).pdfDEPT_NM:생물교육과EMAIL:[email protected]:

Effects of different day length and wind conditions to the seedling growth performance of Phragmites australis

Background To understand shade and wind effects on seedling traits of common reed (Phragmites australis), we conducted a mesocosm experiment manipulating day length (10 h daytime a day as open canopy conditions or 6 h daytime a day as partially closed canopy conditions) and wind speed (0 m/s as windless conditions or 4 m/s as windy conditions). Results Most values of functional traits of leaf blades, culms, and biomass production of P. australis were higher under long day length. In particular, we found sole positive effects of long day length in several functional traits such as internode and leaf blade lengths and the values of above-ground dry weight (DW), rhizome DW, and total DW. Wind-induced effects on functional traits were different depending on functional traits. Wind contributed to relatively low values of chlorophyll contents, angles between leaf blades, mean culm height, and maximum culm height. In contrast, wind contributed to relatively high values of culm density and below-ground DW. Conclusions Although wind appeared to inhibit the vertical growth of P. australis through physiological and morphological changes in leaf blades, it seemed that P. australis might compensate the inhibited vertical growth with increased horizontal growth such as more numerous culms, indicating a highly adaptive characteristic of P. australis in terms of phenotypic plasticity under windy environments.This research was supported by Basic Science Research Program through the National Research Foundation of Korea (NRF) funded by the Ministry of Education (NRF-2015R1D1A1A01057373) and by the National Research Foundation of Korea (NRF) grant funded by the Korean government (Ministry of Science and ICT) (NRF-2018R1A2B2002267)

Differences in functional traits of leaf blade and culm of common reed in four habitat types

We compared the functional traits of leaf blades and culms of common reed (Phragmites australis) in four habitat types of distinguished environments such as temperature, precipitation, water characteristics, and indices related to biomass production (montane fen, MF; riparian marsh, RM; lagoon, LG; and salt marsh, SM). We also examined the relationships between the functional traits within and among populations. Four populations showed remarkable differences in the functional traits of leaf blades and culms. MF and RM had relatively tall (> 300 cm) and thick (> 8 mm) culms bearing long leaf blades (> 40 cm), whereas LG and SM had relatively shorter and thinner culms bearing shorter leaf blades than MF and RM. Some relationships between the functional traits of leaf blades and culms showed negative or not significant correlations within the population, whereas most of the relationships between the functional traits showed positive correlations particularly when all the data from four populations was included into the correlation analysis.This research was supported by the National Research Foundation of Korea (NRF) funded by the Ministry of Education (NRF-2015R1D1A1A01057373) and by the Korea government (MSIT) (NRF-2018R1A2B2002267)

Effects of initial density, nutrient, and water level regime on the seedling survival and growth of Typha orientalis Presl

Seedlings' successful establishment is of importance in the preemption process of pioneers in wetlands. Although Typha orientalis Presl has been reported as a pioneer in Asia countries, studies on the seedling phase of T. orientalis are not available yet. A mesocosm experiment was conducted to understand the effects of biotic (initial density) and abiotic (nutrient and water level regime) factors on the seedling survival and growth of T. orientalis. Most seedlings survived under low initial density (93.8%) and eutrophic (95.5%) rather than high initial density (64.3%) and ombrotrophic (62.5%). Seedlings under low initial density, eutrophic, and flooded conditions showed relatively higher growth in shoot height. The final number of ramets showed an adverse tendency compared to the survival rate and shoot height particularly depending on the water level regime. T. orientalis compensated its biomass production with producing less but longer shoots under the flooded condition, indicating the phenotypic plasticity of T. orientalis as a deep water species. However, the compensation seemed to be guaranteed only under the condition of sufficient nutrients. Asian T. orientalis seemed not to be a pioneer but a weak-competitor not only in mature plant stage but also in juvenile seedling stage unless sufficient nutrients are guaranteed.N

Development of the Hands-free AI Speaker System Supporting Hands-on Science Laboratory Class: A Rapid Prototyping

The recent progress of natural language processing (NLP), speech recognition, and speech generation envisions using hands-free artificial intelligence (AI) speakers in classrooms to support student learning. In science education, the conventional hands-on laboratory education has been considered crucial in fostering students’ manipulative experimentation skills. However, touching things with gloved hands other than experimental equipment and apparatuses is strictly restricted because of the safety issue, which calls for another channel to get timely support. Therefore, we ideated that adopting hands-free AI speakers in the hands-on science laboratory classroom would support student learning. Using the rapid prototyping method, we designed and developed an AI speaker-based system that answers student queries concerning solution-making, experimental process, and waste liquid disposal, which corresponds to the initial, middle, and final phases of a laboratory class. The system was internally validated by usability tests of 9 expert panels and 18 university students, and then revised. The revised system was externally validated in an analytical chemistry experiment class for 3 sessions with 13 university students. We present the result of the prototype development, internal and external validations with quantitative and qualitative data. The AI speaker system enabled students to use the auditory learning mode in the laboratory while concentrating on the experimentation with their hands in the external validation

Soil factors determining the distribution of Phragmites australis and Phacelurus latifolius in upper tidal zone

To assess the environmental factors determining the zonation between Phacelurus latifolius and Phragmites australis, vegetation survey and soil analysis were performed at a tidal marsh. The vegetation of the tidal marsh was classified into P. latifolius and Suaeda japonica dominated quadrats, P. latifolius and P. australis dominated quadrats, P. australis dominated quadrats, and P. australis and other land plants dominated quadrats. The density of P. latifolius (83.7 ± 5.5 shoots m−2) was higher than that of P. australis (79.3 ± 12.1 shoots m−2) in each dominated quadrat but height of two species were similar. Soil environmental characteristics of P. latifolius dominated quadrats appeared to be affected by tide based on higher soil electric conductivity (ECPL = 1530 ± 152 μS cm−1; ECPA + PL = 689 ± 578 μS cm−1; ECPA = 689 ± 578 μS cm−1) and lower pH (pHPL = 5.96 ± 0.16; pHPA + PL = 6.28 ± 0.31; pHPA = 6.38 ± 0.22). In redundancy analysis, environmental characteristics of P. latifolius dominated quadrats and P. australis dominated quadrats were clearly separated and those of P. latifolius and P. australis co-dominated quadrats were similar to P. australis dominated quadrats. From our investigation, P. latifolius showed relatively high competitiveness when compared to P. australis in lower tidal zone rather than upper tidal zone. Zonation of P. latifolius and P. australis seems to be a transitional zone between halophytes and land plant species.This research was supported by the Basic Science Research Program through the National Research Foundation of Korea (NRF) funded by the Ministry of Education (NRF-2015R1D1A1A01057373), the National Research Foundation of Korea (NRF) grant funded by the Korea government (MSIT) (NRF2018R1A2B2002267), and R&E program of Siheung Education Institute for Gifted

Control of runner reed (Phragmites japonicus) in lentic wetlands

In lotic wetlands, runner reed (Phragmites japonicus) plays a role as a pioneer, which helps other plant species to settle by making dense roots trapping floating-sediments. In lentic wetlands, on the other hand, P. japonicus could play a role as an invader threatening biodiversity by forming tall and dense stands. To conserve an abandoned paddy terrace in mountainous areas, a habitat of an endangered dragonfly species (Nannophya pygmaea), from the monotypic-occupation by P. japonicus, we applied three kinds of treatment: (1) hand-clipping in 2009, (2) mechanical excavating in 2012, and (3) planting of alternative vegetational unit in 2012. We have monitored vegetation changes in the wetland in 2008~2012 and 2017. Vegetation cover of P. japonicus sharply decreased from 43% in 2011 to 16% in 2012 by the mechanical excavation. After 5 years from applying the treatment, Schoenoplectiella mucronata that was utilized in the planting became the predominant species instead of P. japonicus and the number of wetland plant species increased from 16 to 25 with the shift in species composition. This study showed the utility of three control methods of P. japonicas in a lentic wetland.This work was supported by Basic Science Research Program through the National Research Foundation of Korea (NRF) funded by the Ministry of Education (NRF-2015R1D1A1A01057373), the National Research Foundation of Korea (NRF) grant funded by the Korea government (MSIT) NRF2018R1A2B2002267), and the Korea Ministry of Environment (MOE) as public technology program based on Environmental Policy.