Diversity and density of crabs in degraded mangrove area at Tanjung Panjang Nature Reserve in Gorontalo, Indonesia

Abstract

Lapolo N, Utina R, Baderan DWK. 2018. Diversity and density of crabs in degraded mangrove area at Tanjung PanjangNature Reserve in Gorontalo, Indonesia. Biodiversitas 19: 1154-1159. This study was aimed to analyze the diversity and the density ofcrabs in a degraded mangrove area including in the intact mangrove area and the fishponds (the degraded mangrove area).. The datafrom this study could be used as supporting data for decision makers to slow down the degradation of mangrove along the area ofTanjung Panjang Natural Reserve. The observed data i.e diversity and density of crabs were collected using the stratified randomsampling method (10 m x 10 m plot). Environmental parameters suited to crab habitat were also measured. The samples were takenfrom 18 spots. The study shows that 20 species of crabs were obtained within the mangrove area, and 11 species were founded withinthe fishponds area. Interestingly, two species of crabs i.e Varuna yui and Varuna litterata were only founded in fishponds area. Thedensity of crabs in mangrove area ranged between 3.23 ind/300m2 and 4.52 ind/300m2, while the density of crabs in fishponds arearanged between 0.16 ind/300m2 and 0.63 ind/300m2. Further study revealed that characteristics and the age of mangrove trees affectedmacrozoobenthic biota (Gastropods, Bivalvia, Mud Lobster, Polychaeta, and shrimp) as well as fish diversity within mangrove inTanjung Panjang Natural Reserve. These may be important for further restoration program of mangrove ecosystem and the sustainablerestocking for conservation purposes.

Crab diversity as support for ecotourism activities in Pejarakan Mangrove Forest, Buleleng, Bali, Indonesia

“…The importance value is determined from 2 parameters, namely: relative density and relative frequency. The criteria for the diversity index are; H'<1.5 then the species diversity is low, 1.5<H'<3.5 means that the species diversity is moderate, and H'>3.5 then the species diversity is high (Krebs 1989). The evenness index (E) is calculated by the formula, E= H/lnS, where H is the diversity index and S is the number of species.…”

“…The evenness index (E) is calculated by the formula, E= H/lnS, where H is the diversity index and S is the number of species. The uniformity index criteria are; if 0<E≤ 0.5 then the mangrove condition is depressed and uniformity is low, if 0.5<E≤0.75 then the condition is less stable and the uniformity is moderate, and if 0.75< E≤1.0 stable condition and high uniformity (Stiling 1996;Krebs 1989;Natania et al 2017).…”

Vegetation structure, species diversity, and mangrove zonation patterns in the Tanjung Panjang Nature Reserve Area, Gorontalo, Indonesia

“…The pond area increased to 297 ha in 2000 and in 2015 the area increased by 7,129 ha (Blue Forests, 2017). This illustrates that the designation of mangrove forests into ponds has increased over a period of 15 years from 2000 to 2015 (Lapolo et al 2018).…”

Spatial distribution of salinity, mud thickness and slope along mangrove ecosystem of the coast of Kupang District, East Nusa Tenggara, Indonesia

“…Mangrove ecosystems are inhabited by various animal species due to their ecological and physical features (Lapolo et al 2018). Mangrove ecosystems also support various species of microorganisms which are highly tolerant to extreme conditions (Retnowati et al 2017).…”

“…Mangrove ecology consists of various organisms, both living on land and in the water (Basyuni et al 2018). Mangroves also protect small fishes and the larvae of fishes and clams, guarding them against predators (Lapolo et al 2018). All these make mangroves very important elements in coastal ecosystems, in various aspects including ecological, social, and economical (Basyuni et al 2018).…”