Paper Sample on Land Crabs and Human Impact: A Study of Chiromantes in the Noto Peninsula

Land crabs mainly occur in tropical America, West Africa, and the Indo-Pacific region. All species feed on plant and animal tissue. Land crabs live a considerable distance from the sea, with some penetrating up to eight kilometers inland. An adult land crab weighs about 0.5 kg and measures about 8 km (Davis, 2019). In the coastal forests in the Noto Peninsula, Ishikawa Prefecture, Japan, two main species of land crabs inhabit this region. These are Chiromantes haematocheir and Chiromantes dehaani. The speech will, therefore, focus on these two types of land crabs and their surrounding environment.

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The C. haematocheir has a ridged, square carapace about 3 cm wide and has a curved smiley mark in the center. The chelae of males are usually red in color, while those of females and juveniles are very small and not easily seen. This species of land crab digs burrows in the grass. During summer, the female crab collects the eggs and takes them to the ocean for hatching (Davis, 2019). On the other hand, C. dehaani is a mudflat crab that typically lives in mangrove swamps. In Japan, this species is commonly known as kurobenkeigani. It has an uneven carapace that is sectioned into four frontal lobes. In addition, the legs of C. dehaani are covered with thick and long setae, and the granular chelipeds contain tubercules.

The land crabs in the coastal forest feed on leaves that fall from the trees and harvest mushrooms, nuts, and invertebrates in the forest. Most of the leaves contain toxic substances; therefore, the crabs either bury the leaves in the ground or soak them in water. This is important because harmful substances interfere with the digestion system. Every year, the females release eggs into the sea. However, fewer numbers of females are observed when there are avian predators or humans (Davis, 2019). In addition, the eggs are sometimes consumed by several marine fishes, such as the striped mullet, while the larval stages of Chiromantes act as food sources for larger fishes, including the Japanese sea perch. Since the larval stage of Chiromantes is widely spread in the Noto Peninsula, it plays a significant role in the diversity of the marine fauna.

Moreover, once the crabs develop into the juvenile stage, they return to their terrestrial habitats. Therefore, the degradation of the coastal forests through deforestation poses a significant threat to Chiromantes. Statistics show that the density of juvenile Chiromantes has significantly reduced from a hundred crabs per m2 to forty crabs per m2 due to the increase in the concrete ground without fallen leaves. A Survey of the Chiromantes in the terrestrial environment shows that they have disappeared from about twelve locations within the Noto Peninsula (Davis, 2019). These locations were occupied by humans who engaged in the construction of houses and deforestation.

Conclusion

In conclusion, it can be noted that the population of land crabs has significantly declined due to the impact of human activities. Construction of houses and deforestation are the main activities that have resulted in the disappearance of Chiromantes. Therefore, it is important to maintain a terrestrial environment to ensure the survival of land crabs. This can be achieved by creating corridors that would ensure Chiromantes effectively utilize both the terrestrial and marine habitats. For instance, Satoyama and Satoumi can be connected to provide a sustainable ecosystem in the Noto Peninsula.

Reference

Davis, M.E. (2019). Protection of land crabs is critical to the conservation of coastal tropical forests. https://news.mongabay.com/2009/07/protection-of-land-crabs-critical-to-the-conservation-of-coastal-tropical-forests/#:~:text=In%20addition%20to%20an%20ability,the%20sea%20only%20to%20reproduce.