• Title/Summary/Keyword: habitat density

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Soil Habitat Characteristics of Cicada Nymph in an Urban Apartment Garden (도심 아파트 단지 화단에 나타나는 매미 약충의 토양 서식처 특성)

  • Kim, Keonhee;Kim, Jae Geun
    • Journal of the Korean Society of Environmental Restoration Technology
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    • v.14 no.3
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    • pp.47-55
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    • 2011
  • Cicada is a very familiar insect to people but habitat characteristics of them are not well known. To investigate habitat characteristics of cicada nymph, plant species, plant cover, soil hardness, accumulated organic mass, organic content in soil, and root density were investigated at 11 sites in an apartment complex garden in Seoul. Selected sites had different densities of cicada nymph case above the ground. Density of cicada nymph case was positively correlated with accumulated organic mass, organic content in soil, and root density and negatively correlated with soil hardness. Even though shrub coverage was not linearly correlated with the density of cicada nymph case, 80% cover of shrub was necessary for the high density of them. Data in this study suggested that organic matter in addition to root density be the primary limitation factor of cicada nymph and high amount of litter-fall decrease soil hardness through the increase of soil organic matter. This study suggests that the density of cicada nymph can be managed through organic content in soil.

Estimation of Stocking Density using Habitat Suitability Index and Ecological Indicator for Oyster Farms in Geoje-Hansan Bay (서식적합도와 생태지표를 이용한 거제한산만 굴양식장의 입식밀도 산정)

  • Cho, Yoon-Sik;Lee, Won-Chan;Hong, Sok-Jin;Kim, Hyung-Chul;Kim, Jeong-Bae;Park, Jung-Hyun
    • Journal of the Korean Society of Marine Environment & Safety
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    • v.18 no.3
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    • pp.185-191
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    • 2012
  • Most of Korean farms have been developed in the semi-closed bay, and its position is very vulnerable to the coastal contamination due to the long term and the high density. So, mariculture management is very essential for the sustainable aquaculture. Some of the specific ways would be the assessment of the optimal stocking density for mariculture management zone and this has to consider both the suitable site selection and the assessment of ecological carrying capacity. Habitat suitability index(0.0 totally unsuitable habitat, 1.0 optimum habitat) and ecological indicator(Filtration pressure indicator) was used to assess the stocking density for oyster farms in Geoje-Hansan Bay. Geoje Bay showed the higher habitat suitability index value 0.75 than Hansan Bay 0.53, indicating that Geoje Bay is more suitable for oyster farming. Ecological indicator showed different stocking density according to the coastal characteristics in Geoje-Hansan Bay. Consequently, it is desirable that the stocking density in Geoje Bay should reduce average 40% and Hansan Bay, average 60% than present, in order to meet the ecological carrying capacity. The assessment of the stocking density could solve various problems such as the coastal contamination, environmental aggravation and the productivity decrease and this study could be a scientific basis to establish the policies for mariculture management.

Differences in Bird Communities Due to Different Habitat Type in Han River Area (한강 유역에서 서식환경에 따른 조류군집의 특성 차이)

  • 허위행;박성진;임신재;박용수;최서윤;이창배;이우신
    • Korean Journal of Environment and Ecology
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    • v.17 no.1
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    • pp.83-91
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    • 2003
  • This study was conducted to clarify the characteristics of bird communities due to different habitat types on 3 sites in Han river area from May 2001 to January 2002. Water area was the most dominant habitat type in each site and also forest was dominant habitat type in site 1(Paldang area). Site 2(Bam island area) had various habitat types e.g. shrub field sandv plain, reed bed and grass field. Total 52 bird species were recorded on 3 sites in Han river. Ducks were the most dominant species, especially in January 2002. Density of individuals were higher in site 1 and 2, but lower in site 3(Nanjido area). In January 2002, dabbling ducks were dominant in site 2, and diving ducks were in site 1. Among diving ducks, common merganser Mergus merganser showed high density in site 2 and pochard Aythya ferina did in site 1. In site 1, coot Fulica atra showed also high density Diverse habitat types could be support foraging resources for dabbling ducks in site 2. High density of pochard and coot would be related to abundant aquatic plants and stable water depth in site 1. Manipulation of riparian zone in site 3 into natural vegetation would increase the bird species diversity. By the manipulation of habitat, habitat potentiality of birds would be increase in Han river area.

Analyzing Priority Management Areas for Domestic Cats (Felis catus) Using Predictions of Distribution Density and Potential Habitat (고양이(Feliscatus)의 분포밀도와 잠재서식지 예측을 이용한 우선 관리 대상 지역 분석)

  • Ahmee Jeong;Sangdon Lee
    • Journal of Environmental Impact Assessment
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    • v.32 no.6
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    • pp.545-555
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    • 2023
  • This study aimed to predict the distribution density and potential habitat of domestic cats (Felis catus) in order to identify core distribution areas. It also aimed to overlay protected areas to identify priority areas for cat management. Kernel density estimation was used to determine the distribution density, and areas with high density were classified in Greater Seoul, Chungnam, Daejeon, and Daegu. Elevation, distance from the used area and roughness were identified as important variables in predicting potential habitat using the MaxEnt model. In addition, the classification of suitable and unsuitable areas based on thresholds showed that the predicted presence of habitat was more extensive in Seoul, Sejong, Daejeon, Chungnam, and Daegu. Core distribution areas were selected by overlapping high-density areas with suitable areas. Priority management areas were identified by overlaying core distribution areas with designated wildlife sanctuaries. As a result, Gyeonggi, and Chungnam have the largest areas. In addition, buffer zones will be implemented to effectively manage the core distribution area and minimize the potential for additional introductions in areas of high management priority, such as protected areas. These results can be used as a basis for investigating the status of the cat's habitat and developing more effective management strategies.

Heterogeneous Habitat for Increasing Biological Diversity

  • Lee, Sang-Don
    • Korean Journal of Environmental Biology
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    • v.21 no.4
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    • pp.337-341
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    • 2003
  • Habitat heterogeneity can enhance biological diversity by providing variation in structural diversity. This paper reviewed heterogeneous habitat serves as a population stability and superior demographic performance (e.g., high density, survivorship, reproductive rate) can be observed compared with organisms with inferior demographic performance. The idea of habitat variation has been further developed in modelling. Furthermore the size and configuration (distribution) of a patch (of a particular habitat type) become effective for the stability of population through hiding places and food resources. Species diversity is related to habitat complexity that provides structural diversity to ground -dwelling organisms. Finally coarse woody debris can enhance habitat complexity thus stabilizing population fluctuation and increasing survivorship.

Influence of Seasonal Forcing on Habitat Use by Bottlenose Dolphins Tursiops truncatus in the Northern Adriatic Sea

  • Bearzi, Giovanni;Azzellino, Arianna;Politi, Elena;Costa, Marina;Bastianini, Mauro
    • Ocean Science Journal
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    • v.43 no.4
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    • pp.175-182
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    • 2008
  • Bottlenose dolphins are the only cetaceans regularly observed in the northern Adriatic Sea, but they survive at low densities and are exposed to significant threats. This study investigates some of the factors that influence habitat use by the animals in a largely homogeneous environment by combining dolphin data with hydrological and physiographical variables sampled from oceanographic ships. Surveys were conducted year-round between 2003 and 2006, totalling 3,397 km of effort. Habitat modelling based on a binary stepwise logistic regression analysis predicted between 81% and 93% of the cells where animals were present. Seven environmental covariates were important predictors: oxygen saturation, water temperature, density anomaly, gradient of density anomaly, turbidity, distance from the nearest coast and bottom depth. The model selected consistent predictors in spring and summer. However, the relationship (inverse or direct) between each predictor and dolphin presence varied among seasons, and different predictors were selected in fall. This suggests that dolphin distribution changed depending on seasonal forcing. As the study area is relatively uniform in terms of bottom topography, habitat use by the animals seems to depend on complex interactions among hydrological variables, caused primarily by seasonal change and likely to determine shifts in prey distribution.

Estimation of ecological flow rate for Zacco platypus based on habitat suitability index considering probability density function (확률밀도함수를 고려한 서식처 적합도 지수에 의한 피라미 생태유량 산정)

  • Jang, Kyeung Ho;Park, Young Ki;Kang, Jae Il;Kim, Min Hwan
    • Journal of Korea Water Resources Association
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    • v.51 no.3
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    • pp.207-219
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    • 2018
  • In this study, the ecological flow rate of the Zacco playtypus habitat was simulated based on the Instream Flow Incremental Methodology (IFIM) in reachs of urban and natural stream using the habitat suitability index (HSI) of the probability density function (PDF). To apply this method, PHABSIM model was used in this study. However, in this study, the HSI of the probability density function was developed by adjusting the parameters of the PDF based on Kang (2010) HSI. As a result, the normal distribution is closest to the ecological flow rate of the Kang (2010) in the urban stream. However, the two-parameter log-pearson distribution tended to be the closest in the natural stream. The ecological flow rate was simulated by the HSI and the reach of stream with the PDF. Based on the comparison of simulation results, we propose an ecological flow rate estimation method using probabilistic method.

Establishing a Korean Goral (Nemorhaedus caudatus raddeanus Heude) Reserve in Soraksan National Park, Korea: Based on Habitat Suitability Model, Habitat Capability Model, and the Concept of Minimum Viable Population (설악산 국립공원의 산양 보호구역 설정기법에 관한 연구: 서식지 적합성 모형, 서식지 수용능력, 최소 존속 개체군 이론을 이용하여)

  • Choi, Tae-Young;Park, Chong-Hwa
    • Journal of the Korean Institute of Landscape Architecture
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    • v.32 no.6 s.107
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    • pp.23-35
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    • 2005
  • Korean goral (Nemorhaedus caudatus raddeanus) is an endangered species in Korea, and the rugged terrain of the Sorksan National Park $(373km^2)$ is a critical habitat for the species. Since the goral population is threatened by habitat fragmentation, it is essential to establish a reserve for the isolated goral population. The objective of this study was to propose a reserve for Korean goral in the national Park We employed habitat suitability model, habitat capability model, and the concept of minimum viable population. The results of the study were as follows. First, the carrying capacity and optimal density of gorals in the national park were projected to be 449 gorals, and 251 gorals, respectively Second, since only one patch was projected to satisfy the criteria of minimum viable population (50 individuals/during 50 years), the long term extinction possibility of gorals in the site would be very high. Finally, the patch that satisfy the minimum viable population of goral was proposed as the core zone of the goral reserve and adjacent patches were included as buffer zones.

Using habitat suitability model for the wild boar (Sus scrofa Linnaeus) to select wildlife passage sites in extensively disturbed temperate forests

  • Rho, Paikho
    • Journal of Ecology and Environment
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    • v.38 no.2
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    • pp.163-173
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    • 2015
  • The occurrence of wild boars (Sus scrofa Linnaeus) and reports of wildlife-vehicle conflicts (i.e., road-kill) involving them have increased in natural forest regions of Korea. In the past few decades, many wildlife passages have been constructed to reduce vehicle collisions involving wildlife species. However, few studies have assessed the habitat suitability of target wildlife species when locating the construction sites of wildlife passages. Target species rarely use wildlife passages if built in an inappropriate location. Therefore, a quantitative habitat model is required to find suitable sites for wildlife passages that can connect the fragmented forest patches of wildlife habitats in Korea. In this study, the wild boar was selected as the target species, and six environmental variables (percentage of Quercus forest, slope aspect, distance to roads, water accessibility, forest stand age and density) were measured. The habitat model for wild boars was developed with a Delphi survey, and habitat suitability maps were delineated for the provinces of Gangwon-do and Jeollanam-do. In this study, 298 and 64 boars were observed in Gangwon-do and Jeollanam-do, respectively. Observations of wild boars derived from the second nationwide natural environmental survey were used to evaluate the habitat model. Habitat suitability maps that superimposed existing road networks suggested that wild boar habitats were severely fragmented in both provinces, particularly in Gangwon-do. To connect the fragmented habitats and prevent wildlife-vehicle collisions, this study proposes 11 and 5 wildlife passage sites in Gangwon-do and Jeollanam-do, respectively.

An Analysis of Ecological Habitat Characteristics in Medium-scale Stream -A Case of the Bokha Stream- (중규모 하천 생물 서식처의 특성 분석 -복하천을 중심으로-)

  • 안홍규;우효섭
    • Journal of the Korean Institute of Landscape Architecture
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    • v.32 no.2
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    • pp.102-119
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    • 2004
  • This study investigates the relation between the location of a habitat and the ecological connections according to the habitat type in the riparian zone at the Bokha stream. Stream habitat is classified into nine types for the aquatic insects and fish. For vegetation and birds, habitat is classified into five types of medium-scale streams, including both physical and chemical streams are analyzed accordingly. The major results of this study are as follows: 1) A pool connected to the main stream has a certain water depth (about 80 cm) and is disturbed at least 5 to 6 times a year. Although the pool has a somewhat bad water quality, it provides a habitat for various types of young fish. 2) A meander riffle is about 15 cm deep, the flow velocity in the region is about 75 cm/s. This region does not have large structures to which aquatic insects can attach, so it cannot be used as a spawning ground. 3) A rock type pool is about 60 cm deep, the flow velocity in the meander riffle is about 25 cm/s. In this region, many aquatic insects attached to large structures appear. Due to various riparian vegetation, the rock type pool is used as a habitat for aquatic insects. 4) A pool which is only connected to the main stream during floods has a bad water quality. Despite of its relatively small size, it has a high population density of aquatic insects. faculty.