Spatial Estimation for Establishing Fireflies Habitat in Daegu City and Gyeongbuk Province

Abstract

The purpose of this study is to evaluate the natural habitat of Hotaria unmunsana Doi, which was first discovered at Mt. Unmun also represents a landscape indicator species for Daegu and Gyeongbuk provinces, and Luciola lateralis Motschulsky, which is the object of experiential activation at festivals in some cities in the region. The spatial range of this study is limited by Daegu City and Gyeongbuk province, and is used to predict the preference of firefly for altitude, slope, direction, shaded relief, riparian buffer zone, river environment, and farmland to analyze the area that best matches the habitat of fireflies. As a result, fireflies are highly influenced by altitude and there may be no large-scale habitats in some areas through the Nakdong and the Baekdu mountain ranges, which occur at high altitude. In most of the cities, we found major habitats around the streams and wetlands. By region, the sites were widely distributed around the cities focused on Nakdong River, and many habitats emerged around the Nakdong River tributary and gentle slopes. In order to preserve and spread the habitat of fireflies, the physical environment as well as their relationship with food chains and symbiotic organisms should be established, and excessive use of pesticides and herbicides in agricultural areas should be avoided.

Introduction

Daegu and Gyeongbuk Provinces represent the northern regions of the Nakdong River basin. They are repositories of Korea's ecosystem, which includes forests, rivers and lakes, which are comparable to Gangwon Province. In particular, the huge mountain ranges formed in the northern part of Gyeongbuk Province contain biomass that supports the entire province. The Nakdong River stream flowing along with it forms a water stream that can sufficiently cope with the water flowing from each watershed.

However, over the past several decades, large and small developmental damage has led to a qualitative loss in natural value at an increasing number of places, resulting in scenery connecting extremely artificial space with natural environment.

The Daegu and Gyeongbuk areas, which cover the entire upper watershed of the Nakdong River, also share the same developmental history as the nation. Looking at the environmental policies so far, the emphasis is on exploration and development of natural resources rather than conservation, restoration, or restoration of natural resources. Therefore, the original intention of conservation of natural resources, is not a priority, and instead, utilization-oriented policy is emphasized. Thus, the sustainability of natural resources is not adequate (Kang et al. 2006).

Accordingly, we seek to discover the excellent natural resources in the Daegu and Gyeongbuk provinces, to develop landscape indicator species. Based on habitat expansion and establishing a habitat network visible from any area, a strategy is needed to revitalize the region via long-term image enhancement of Daegu and Gyeongbuk provinces.

The purpose of this study is to evaluate the habitat as a basis for the formation and spread of natural habitat of Hotaria unmunsana Doi (Doi 1931), which was first discovered at Mt. Unmun and represents a landscape indicator species for Daegu and Gyeongbuk provinces, and Luciola lateralis Motschulsky (Oh et al. 2009), which is the object of experiential activation at festivals in some cities in the region.

Materials and Methods

Introduction of target area

The spatial range of this study is defined by Daegu and Gyeongbuk provinces. Basically, the natural environments of Daegu and Gyeongbuk are considered comprehensively, and the areas that best match the habitat of fireflies are analyzed. In the analysis of habitat environment, spatial correlation was performed considering the relationship between habitats such as forests, rivers, and lakes in terms of habitat concept as well as forests.

Introduction of target species

There are about 2,000 species of fireflies in the world (Ohba et al. 1993). In Korea, there are 3 families including 6 genera and 8 species including Luciola lateralis Motschulsky, Lychnuris rufa (Olivier), Hotaria papariensis, Lucidina kotbandia, Drilaster unicolor, Hotaria unmunsana Doi, Lampyris noctiluca (Linnaeus) and Lucidina accensa. Firefly is an insect belonging to Coloptera, Lamptridae. Currently, only Luciola lateralis Motschulsky, Hotaria unmunsana Doi and Lychnuris rufa (Olivier) are found in Korea. However, even these species are currently facing the threat of extinction (Suzuki 2001).

The seasonal appearance of fireflies is as follows: Hotaria unmunsana Doi is observed in late May to early July (Sim et al. 1999) and Luciola lateralis Motschulsky is detected in early June to late July (Oh et al. 2009). Lychnuris rufa (Olivier) is observed from late July to late September (Kim et al. 2000; Kim et al. 2004).

Overall, fireflies are observed in late spring to autumn. The firefly can be classified into diurnal and nocturnal habits according to their ecological behavior (Sim and Kwon 2000). The nocturnal firefly can be divided based on continuous and flashing light emission. Among the fireflies inhabiting Korea, Lychnuris rufa (Olivier) exhibits strong continuous light emission, while Luciola lateralis Motschulsky and Hotaria unmunsana Doi emit a strong flashing lightemission.

The body is generally thin, long and somewhat flat, with the adult size measuring less than 1 cm as in Luciola lateralis Motschulsky, and occasionally 1 to 2 cm, for examples, Lychnuris rufa (Olivier). Larvae are larger than adults, and Lychnuris rufa (Olivier) is about 3 to 5 cm. Often, when the thorax extends to the front of the head, the head is almost or completely invisible. Antennae are thread-like, serrated, comb-like, and 11-segmented, with 3 pairs of legs attached to the chest, and each ankle segment comprises 5 segments. The elytra are flattened; however, the male always carry elytra unlike the female, and hindwing depending on the species. The abdomen consists of 7 to 8 segments and emits light at the end of the abdomen. At the time of light emission, 100% of the energy is converted to light, and luciferin, which is produced in the cells of the light-producing organ, is oxidized resulting in light emission. The light produced by the firefly is a signal for mating, with either male or female glowing to inform the location of the male. The larva of the fireflies emits light faintly. Since the time to generate light varies from species to species, it is an important distinguishing feature. Firefly is a representative environmental indicator insect, and is particularly vulnerable to environmental pollution such as contaminated water compared to other insects (Kim et al. 2008). Most firefly larvae live on terrestrial grasslands, wetlands, coastal wetlands and forests, and very few firefly larval species such as Luciola lateralis Motschulsky live in freshwater and intake snails as carnivores.

Prediction of the firefly habitat

Fireflies, terrestrial or aquatic, have common habitats. Especially, in the geographical condition, it is easy to identify the firefly habitat under the following conditions.

First, an altitude that is not too high is advantageous for firefly habitat. In the case of aquatic species, it was confirmed that the deeper the water level, the faster the flow rate, which is not favorable for the firefly larvae (Oh et al. 2009). In case of terrestrial species, a high density of snails, which are the food source of fireflies, was found on gentle slopes. Therefore, it is expected to be beneficial for the firefly habitat because the density of the food source is increased at the periphery of the gently flat plain and the mountain, similar to the altitude. Fireflies are nocturnal species, therefore, both larvae and adults prefer dark and shaded areas. Accordingly, compared with direct sunlight, the area where the scattered light enters or the sunlight is as brief as possible is advantageous for the habitat. Proximity to the stream or the water source is an advantage, suggesting that fireflies also prefer aquatic habitat similar to all other species.

Contrary to the favorable habitat conditions mentioned above, artificial light (light) produced by the street lamps and artificial structures in the city are the most detrimental factor preventing the life fireflies. Therefore, it is mandatory to exclude firefly habitats from specific locations of these artificial structures and roads.

First, for aquatic fireflies, secondary selection was made for areas with large paddy fields containing static water. These areas can be considered to exhibit the characteristics of a natural aquatic wetland at a gentle and sunlight is blocked to some extent. For terrestrial fireflies, we have selected a favorable environment for the habitat to satisfy the common conditions and contain adequate forests. As a result, areas with forests of adequate size (at least 3,900 m2 ) were selected secondarily and classified as suitable for terrestrial species (Fig. 1).

 

Fig. 1. Weighting method for habitat analysis.

Results and Discussion

A Spatial estimation for establishing the firefly habitat

Analysis of altitude

Based on the elevation analysis, 20.5% of Gyeongbuk area, or 1,091.4 km2 , is less than 100 m in altitude and distributed largely in the vicinity of Nakdong river including the Andong and Daegu basins. More than 80% of the area is at an altitude greater than 100 m. A mountainous terrain with an altitude exceeding 1,000 m above sea level exists in North Gyeongsang Province. The average altitude is 772.5 m (S.D.: 446.4 m), showing a clear difference in altitude between the vicinity of the Nakdong River and the northern mountainous regions.

Lower altitudes are more advantageous than the higher altitudes for firefly habitat. As a result, similar to the slope analysis above, the vicinity of Nakdong River constituting the green area in Fig. 2 appears to be at a low altitude and is considered as favorable for firefly habitat (Fig. 2).

Fig. 2. Estimation of the firefly habitat based on altitude analysis.

Analysis of slope

Slope greater than 15° in Daegu and Gyeongbuk area, which is considered as a disadvantage, is 11,048.7 km2 , which is 55.4% of the total area. The steep slope is maintained in the northern part of Gyeongbuk and the Nakdong mountain range. The slope is relatively high because of the mountainous terrain generally seen. Generally, fireflies were found to live in high density at a lower slope rather than a higher slope. Therefore, the area near the Nakdong River green portion in Fig. 3 is thick, with a gentle slope, and seen at appropriate places (Fig. 3).

 

Fig. 3. Estimation of the habitat of firefly by slope analysis.

Estimation for the firefly habitat by directional analysis

The northeastern surface exposed to limited direct sunlight represents the best habitat condition for direction. The total area of the 23 districts in Daegu and Gyeongbuk provinces meeting this condition was 2,285.71 km2 and the average area was 99.38 km2 (Fig. 4). In the case of Gyeongju City, Bonghwa County, Sangju City, Andong City, Uiseong County, and Pohang City, contain significantly larger areas than the average. Gyeongsan City, Goryeong County, and Chilgok County contain substantially smaller areas than the average. Most of the irradiated areas above the average area were located in the northeastern part of the Sobaeksan and Nakdong mountain ranges. However, even in the northern slope, it is difficult to locate firefly habitats in high altitude areas. Therefore, it is necessary to select appropriate sites considering various environmental factors such as elevation and slope.

Fig. 4. Estimation of the firefly habitat using directional analysis.

Estimation of the firefly habitat by shaded relief analysis

Shaded relief information is a three-dimensional representation of the shading effect that appears as the ground surface is illuminated by the elevation of the terrain during the sun’s circumnavigation. Fireflies mostly prefer areas of shadow formation by terrain regardless of the circumference of the sunlight. The total proper land area of Daegu and Gyeongbuk was 2019.7 km2 and the average area was 87.81 km2 (Fig. 5). Areas in Gyeongju City, Bonghwa County, Sangju City, Andong City, Uljin County, and Uiseong County are larger than the average. Areas in Gyeongsan City, Goryeong County, and Chilgok County are much smaller than the average. Huge shaded areas are preferred by aquatic fireflies including Luciola lateralis Motschulsky as well as terrestrial fireflies. Therefore, habitat analysis reflecting substantially shaded areas is necessary

 

Fig. 5. Estimation of the firefly habitat using shaded relief map.

Estimation of the firefly habitat based on waterfront area

According to the River Act, rivers can be divided into national and local rivers. The national/local rivers in Daegu and Gyeongbuk areas are 167.27 km2 and the river zone is 598.1 km2 . The stream area was measured with a 500 m buffer on the left and right. As a result, Andong city comprises the largest area around Andong lake, and contains buffer zones of 200 km2 or greater in the following order: Bonghwa County, Uiseong County, Sangju County, Cheongsong County, Uljin County and Yungyang County. Gyeongju City, Chilgok County, Daegu City, Goryeong County, Sungju County, Gyeongsan City, and Chungdo County carry an area of less than 100 km2 . The area with a wide buffer zone is widespread in the northern part of Gyeongbuk province, and the area less than 100 km2 is located in the southern part of Gyeongbuk province, including Yeongcheon City and Gunwi County, and mostly in proximity to Daegu city. These areas contain wide riparian buffer zone based on lake and swamp resources such as Yeongcheon and Gunwi lakes (Fig. 6).

 

Fig. 6. Analysis of riparian buffer zone in Daegu and Gyeongbuk.

Estimation of the firefly habitat based on river environment analysis

A total of 4,058 rivers run along the Nakdong River, with a total length of 11,560 km. They include 6 national rivers with a length of 430 km and 359 local rivers with a length of 4,203 km. A total of 16,700 km of river need improvement, and a total of 8,483 km of river is improved. According to the river area map, Andong city includes the widest area of 79.31 km2 , centered on Andong lake (Fig. 7). This area is much larger than other areas, followed by Gumi City and Yecheon County with an area of more than 20 km2 . It can be seen that the river is formed along the area located to the west from north of Gyeongbuk province and the area alongside. The eastern part of Gyeongbuk province is weak in river formation. The Nakdong River flowing along the west from North of Gyeongsangbuk-do, originates from Gangwon Province, and joins the Banbyun stream near Andong. It merges with the western tributaries such as Mi, Naesung, and Yung streams. It then joins Wui and Gam streams, and the Gumho river and finally flows into Gyeongnam. On the east coast of Gyeongbuk province, the Taebaek mountain range is shifted to the east and the altitude is high. Streams such as Wangpyu and Namdae of Uljin County, Song and Gogye of Yeongdeok County, Gogang of Pohang City and Hyungsan river flow through Gyeongju City. When the buffer area of the stream and the area of the river are combined, the northwestern part of Gyeongsangbuk-do has a wide river area. However, due to the nature of Luciola lateralis Motschulsky, it is necessary to select an appropriate place based on the presence of light, altitude, and slope as well as river distribution.

 

Fig. 7. Estimation of the firefly habitat based on the river environment.

Estimation of the firefly habitat based on farmland analysis

According to cadastral act, land categories are classified as follows: farm land, paddy field, orchard, pasture, forest land, mineral springs (land coming out of hot spring water), salt pond, factory site, parking lot, gas station site, warehouse site, road, railroad area, bank, stream, canal (artificial waterway, dike), pond marsh (reservoir), fish farm, water supply site, park, physical site, recreation ground, religious site, historic site, graveyard, miscellaneous land, etc. Among these land categories, the paddy field represents the most appropriate habitat for Luciola lateralis Motschulsky, and the place marked on the map of Fig. 8 is the extracted paddy field. The paddy field area of Gyeongbuk province accounted for 14.43% and the paddy field distribution by each city was 180.18 km2 (9.26%) in Sangju city, 171.10 km2 (8.83%) in Gyeongju city, 137.59 km2 (7.07%) in Uisung County, 121.62 km2 (6.25%) in Gimcheon City, 114.25 km2 (5.89%) in Yecheon, and 104.42 km2 (5.36%) in Gumi (Fig. 8). The distribution pattern of paddy fields is closely related to the proximity of the Nakdong River. In the upper distribution, Gyeongju accounts for a high proportion of the paddy field, but it is less suitable as a Luciola lateralis Motschulsky habitat due to its location adjacent to the water system and urban tourism reserves.

Fig. 8. Estimation of the firefly habitat based on the farmland environment.

Comprehensive analysis

As a result of the foregoing analysis, we conclude the habitat suitability as follows. Of course, the habitat is highly affected by altitude and is not present in some parts of the Nakdong and the Baekdu mountain ranges, which are very high altitudes. However, in most of the cities and counties, major habitats were found around rivers and wetlands.

By region, many emergence sites were centered around Nakdong river such as Yeongju, Yecheon, Sangju, Gumi, Chilgok. Emergence sites were also found in Yeongcheon, Gyeongsan, and Cheongdo.

Conclusion

For the restoration of Hotaria unmunsana Doi, the representative indicator of Daegu and Gyeongbuk province and first discovered in Chungdo County Mt. Unmun, and Luciola lateralis Motschulsky, well known inhabitant of Gyeongbuk province, we analyze and predict the habitat as follow.

First, for spatial estimation of firefly habitat, we tried to predict firefly preferences by analyzing altitude, slope, direction, shaded relief, riparian buffer zone, river environment, and farmland.

As a result, fireflies are highly influenced by altitude. No large-scale habitats may exist in specific high-altitude areas through the Nakdong and the Baekdu mountain ranges. In most of the cities and counties, we found major habitats around the streams and wetlands

By region, there were many emergence sites centered in the Nakdong river such as Yeongju, Yecheon, Sangju, Gumi, Chilgok. Emergence sites were also found in Yeongcheon, Gyeongsan, and Cheongdo (Fig. 9 and Fig. 10).

 

Fig. 9. Habitats suitability analysis for aquatic firefly.

Fig. 10. Habitat suitability analysis for terrestrial firefly.

In order to preserve and spread the firefly habitat, it is necessary to establish the relationship between their physical environment, and food chains and symbiotic organisms. For more effective restoration of firefly habitat, a food chain structure and a firefly habitat system must be established. In addition, the habitat restoration plan should be concurrent with deforestation measures.