- KOREAN
- P-ISSN2287-8327
- E-ISSN2288-1220
- SCOPUS, KCI
ISSN : 2287-8327
Vol.32 No.3
Abstract
Pre-dispersal seed predation by a granivorous bird, the masked grosbeak(Eophona personata, Fringillidae), was investigated in two bird-dispersed trees, Celtis sinensis and Aphananthe aspera(Ulmaceae). The objectives of this study were to 1)measure direct damage of predation by grosbeaks on plant crops, 2) reveal the temporal pattern of predation within each tree species and its causal factors, and 3) test whether foraging grosbeaks hinder foraging of frugivorous birds, thereby indirectly impacting the reproduction of both tree species. A substantial amount of fruit and seed crop was consumed by grosbeaks(24.3% in Celtis;55.5% in Aphananthe), and only 17.7%(Celtis) and 16.7%(Aphananthe) were removed by frugivorous birds. At the study site, the grosbeak population size fluctuated greatly during the fruiting seasons of both plant species. As for Celtis, predated seed density also fluctuated temporally, and the local population size of grosbeaks was responsible for predated seed density. In Aphananthe, predation was not fully explained by grosbeak populations or plant phenology, but its peak coincided with that of grosbeak population. These results suggest that pre-dispersal seed predation by granivorous birds can have large negative impacts on the bird-dispersed plants. Changes in local population size of granivorous birds can influence predatation and can affect reproductive success of the bird-dispersed plants available to the birds.
Abstract
To understand whether experience of cold season in reproductive behaviors in the adults of Amaurobius ferox, the paired adults of a female and a male were exposed under cold-treated environment’and not cold-treated environment’, respectively. I investigated effects of the cold treatment on the brood production of A. ferox. In not cold treatment in which male-female pairs were formed in October at a temperature of 20℃(±2℃) and continuously kept under not cold-treated environment, only 3 of 50 pairs successfully reproduced (reproduction was defined as the emergence of spiderlings). In cold treatment where individuals were kept in cold conditions for 3 months prior to pair formation, 57 out of 60 couple succeeded in reproducing. Females which did not experience the low temperature displayed strong aggressiveness toward males. This behavioral inhibition might the primary barrier to copulation of A. ferox that decrease following a period of low temperature. The reproductive inhibition might help the females to allocate the maximum amount of energy in a given environment to reaching the adult stage and to delay reproduction in unfavorable wintering conditions.
Abstract
American sycamore seedlings were grown in chambers with two different ozone concentrations (O₃-free air and air with additional O₃) for 45 days. Both the control and the O₃chambers included non-fertilized and fertilized plants. After 18 days of O₃fumigation, seedlings were placed in a clean chamber for 27 days. Seedlings under ozone fumigation showed a significant decrease in pigment contents and photosynthetic activity, and a significant increase in lipid peroxidation. Fertilization enhanced physiological damage such as the inhibition of photosynthetic activity and the increase of lipid peroxidation under ozone fumigation. During the recovery phase, the physiological damage level of seedlings increased with ozone fumigation. In addition, physiological damage was observed in the fertilized seedlings. Superoxide dismutase (SOD) and glutathione reductase (GR) activities of O₃-treated seedlings increased up to 33.8% and 16.3% in the fertilized plants. The increase of SOD activity was higher in the fertilized plants than in the non-fertilized plants. Negative effects of ozone treatment were observed in the biomass of the leaves and the total dry weight of the fertilized sycamore seedlings. The O₃-treated seedlings decreased in stem, root and total dry weight, and the loss of biomass was statistically significant in the fertilized plants. In conclusion, physiological disturbance under normal nutrient conditions has an effect on growth response. In contrast, in conditions of energy shortage, although stress represents a physio-logical inhibition, it does not seem to affect the growth response.
Abstract
The purpose of this study was to investigate the effects of thinning on fine root biomass and vertical distribution and litterfall amount in a 50 year old Pinus koraiensis plantation in Chuncheon, Kangwon Province. Fine root (< 2 mm in diameter) biomass (367 g/m²) in the site ‘OC_75’, thinning once in 1975, was 68% of those in the site ‘CON’, no thinning after planting, and in the site ‘TC_00’, thinning twice in 1975 and 2000. There were no significant differences of dead roots among treatments. Diameter 0∼1 mm roots were vertically decreased only in the TC_00 site. The litterfall was very similar between OC_75 (5.2 Mg ha⁻¹ yr⁻¹) and TC_00 (4.7 Mg ha⁻¹ yr⁻¹), but the composition of litterfall was different: The proportion of leaves and branches was 80% and 13% in OC_75 and 56% and 36% in TC_00, respectively. Reduction of P. koraiensis density by thinning decreased leaf litter as well as fine roots of P. koraiensis, but increased fine roots production by neighboring understory plants offset the reduction of fine roots of P. koraiensis. We suggest that belowground as well as aboveground responses, including both over- and understory vegetation, should be considered to measure the responses of trees in thinned forest ecosystems.
Abstract
Land cover changes associated with urbanization have driven climate change and pollution, which alter properties of ecosystems at local, regional, and continental scales. Thus, the relationships among urban ecological variables such as community composition, structure, health, soil and functioning need to be better understood to restore and improve urban ecosystems. In this study, we discuss urban ecosystem management and research from a futuristic perspective based on analyses of vegetation structure, composition, and succe-ssional trends, as well as the chemical properties of soils and the distribution of heat along an urban-rural gradient. Urban thermo-profile analysis using satellite images showed an obvious mitigating effect of vegetation on the Seoul heat island. Community attributes of Quercus mongolica stands reflected the effects of urbanization, such as pronounced increases in disturbance-related and pollution-tolerant species, such as Styrax japonica and Sorbus alnifolia. Retrogressive successional trends were detected in urban sites relative to those in rural sites. Changes in the urban climate and biotic environment have the potential to significantly influence the practice and outcomes of ecological management, restoration and forecasting because of the associated changes in future bio-physical settings. Thus, for management (i.e., creation and restoration) of urban green spaces, forward-thinking perspectives supported by historical information are necessary.
Abstract
The optimal strategy for semelparous females may involve djustments in the relative investment in two fitness components, the number of offspring and the post-hatching investment per capita. To determine the pattern of maternal resource allocation to offspring in the matriphagous spider, Amaurobius ferox (Amauro-biidae), I investigated the relationship between maternal body-mass and the number of offspring, and quantified the transfer of maternal body-mass to the offspring via different forms of maternal provisioning (trophic egg-laying and matriphagy). There was a positive relationship between female body-mass and the number of offspring. However, Amaurobius mothers did not produce more trophic eggs when they had larger broods. Rather, spider-lings in larger A. ferox broods consumed larger quantities of maternal body-mass via matriphagy. Mothers trans ferred 28.8±6.5% of their body-mass to the spiderlings via trophic egg-laying, and an estimated 39.0±12.5% of their body-mass was transferred to the spiderlings via matriphagy
Abstract
This research focused on the effects of fragmentation on moth diversity in an agricultural land-scape by comparing moth species richness and abundance between hillocks and young secondary forests. We examined five sites from the southwestern part of South Korea: three sites from hillock forest and two from secondary forest. We collected moths bi-weekly from April to October for a 2-year period (2006-2007) with a UV light trap that usually attracts moths within 30 meters. Tree species richness and abundance in 20 m × 20 m plots at each moth sampling site showed a substantial difference in tree diversity between the two types of forest habitats. The total abundance and richness of moth species were higher in secondary forests (541 species with 4,998 individuals) than in hillock forests (423 species with 3,913 individuals), irrespective of the distance among the sites. An ordination analysis with NMDS showed that habitat is the most important factor of grouping sites. The food preferences of the dominant moth species in each habitat were closely related to the habitat type.
Abstract
We monitored 38 hibernation sites of Myotis formosus in South Korea and recorded the number of bats occupying each site and assessed the micro-climate at the sites during four winters from 2005 to 2009 at. The mean rock temperature of the bat roosting sites was 13.2±1.4℃ and themean body temperature of the hibernating bats was 13.3±1.3℃. The number of hibernating bats was negatively related to the size of the entrance and positively related to the minimum ambient temperature and humidity in the site interior. More bats hibernated in roosts with smaller entrances and higher minimum ambient temperatures, and more bats selected sites presenting a narrow temperature range. This study showed that the internal environments of hibernacula of M. formosus were highly stable despite dramatic variation in the external environment.
Abstract
Benthic macroinvertebrate communities were collected from six different sites in the Dobong Stream in Seoul, Korea to investigate spatial and temporal changes in benthic macroinvertebrate communities in response to natural isturbances such as floods and droughts. We collected samples monthly or semimonthly with a Surber net (30 cm × 30 cm), and measured environmental factors, including stream temperature, discharge, width, conductivity, dissolved oxygen and pH at each sampling site. Benthic macroinvertebrates were strongly affected by floods as well as droughts. In addition, benthic macroinvertebrate communities displayed different responses to the onset of the rainy season in summer 2006 and 2007, apparently due to differences in the inten-sity and amount of precipitation. Chironomids were particularly sensitive to heavy rain. Floods and droughts also affected the proportions of functional feeding groups during the survey period: the proportion of scrapers was high right after heavy rains, while the proportion of predators tended to increase in intermittent-type streams as the riffle zone decreased. Finally, although species richness and abundance were strongly influenced by heavy rain, they recovered to background levels for within one month, and varied consistently among stream types, indicating habitat stability.
Abstract
Greenbelts were designated by the Korean government in 1971 in 14 large cities to prevent uncontrolled urban expansion. Recently, deregulation of the greenbelt system has resulted in further develop-ment, but the ecological role of greenbelts has not been fully considered when decisions about urban manage-ment are being made. We examined the ecological roles of the greenbelt system in the Seoul metropolitan area and prepared sustainable management and improvement plans based on our analysis of landscape characte-ristics using satellite images covering a ∼30-year period. The loss of forest cover during this period in the greenbelt areas was lower than that in the areas outside and inside of the greenbelt. Fragmentation of forest cover was correlated with the pattern of loss of forest cover. The NDVI of the greenbelt remained steady at 90% of that in outside of the GB for three decades. This suggests that the greenbelt system has performed its primary roles well. However, the remaining green space was not adequate to provide a sink for air pollutants even when the greenbelt area was included. We discuss how the negative effects of urbanization can be reduced through sustainable management and restoration to promote ecological functioning in greenbelts and urban landscapes.