Influence of a microhabitat on the structuring of the benthic macrofaunal community in a mangrove forest

Abstract

Habitat heterogeneity contributes to the maintenance of species diversity; however, little is known about the influence of microhabitat heterogeneity on the diversity of mangrove invertebrates. We tested the hypothesis that the structures of benthic faunal communities differ among microhabitats because each microhabitat function differs widely according to their physical properties. The descriptors of invertebrate assemblages were determined every March (dry season) and August (wet season) of 2005, 2006, and 2007 in three different mangrove microhabitats-tidal creek, deep forest, and canopy gapof an intertidal mangrove forest around the Sikao Creek in the Trang Province of southern Thailand. The physical properties of the selected microhabitats were studied in 2005. The properties of each microhabitat varied, especially with respect to the light intensity and sediment moisture content: the tidal creeks were wet and well-exposed to sunlight, forest interiors were moist and dark, and the canopy gaps were dry and well-exposed to sunlight. Seasonal differences in the microhabitats were also noted. The numerical abundance and biomass of benthic macrofauna differed among the microhabitats; both values were the highest in canopy gaps, and these values increased in the wet season. Despite seasonal differences, species composition differed in the three microhabitats; the majority of animals were members of the epifauna; these were surface deposit feeders. Each microhabitat functioned differently because their physical properties were disparate. A diverse benthic faunal community is formed by a combination of different functional microhabitats in mangrove ecosystems, thereby indicating that microhabitat heterogeneity should be considered as an important factor influencing the structuring of a benthic community.Electronic supplementary material The online version of this article (

Do allochthonous inputs represent an important food resource for benthic macrofaunal communities in tropical estuarine mudflats?

“…In turn, the differences in community species composition are caused by differences in the physical characteristics of the substrate sediment at this site, in comparison to those of the sediment at other sites. A unique community could be established in organically enriched sediment (Carvalho et al, 2011), as benthic macroinvertebrates depend on the physicochemical properties of the sediment (Alfaro, 2006;Ganesh and Raman, 2007;Kon et al, 2011). The Raytrang sediments contained mangrove-derived materials (Table 3), and thus, riverine allochthonous materials might function as a spatial resource by providing habitat substrate to benthic communities, as has been reported to occur in temperate mudflats (Kon et al, 2012).…”

The Effect of Shading and Nutrient Addition on the Microphytobenthos, Macrofauna, and Biogeochemical Properties of Intertidal Flat Sediments

“…On rocky shores and seawalls, shading ameliorates stressful conditions (Blockley, 2007), for example by decreasing physical stresses associated with emersion during low tide, particularly temperature and desiccation (Thompson et al, 2004). Mangrove canopy directly alters physical conditions such as temperature and moisture, with concomitant changes to sediment properties and organisms (Kon et al, 2011). Latitude and its effects on temperature, insolation and day-length play an important role in regulating microphytobenthos biomass and their response to shading.…”

“…The relative importance of direct changes to sediment due to shading caused by these blooms, or indirect changes due to anoxia or other processes associated with the algae is not always clear. Shading of habitat can be very important in determining distributions and abundances of organisms, which may be affected either directly by changes in environmental stress, or indirectly via changes to biotic relationships (e.g., Wiens, 1976;Defew et al, 2004;Kon et al, 2011). On rocky shores and seawalls, shading can increase or decrease amounts of algae and change sessile assemblages (Williams, 1994;Blockley, 2007) or cause mobile animals to aggregate (Takada, 1999).…”

“…The canopy of mangrove trees can cast deep shade over the substratum. Previous work has shown that intertidal benthic assemblages differ between muddy substratum that is continuously shaded, periodically shaded and nearby unshaded substratum Tolhurst, 2004, 2007;Tolhurst and Chapman, 2007;Kon et al, 2010Kon et al, , 2011Tolhurst et al, 2010). Leaf litter is the largest constituent of mangrove organic matter contributing to food chains (Lee, 2008), the decomposition of which releases nutrients to the ecosystem (Kamruzzaman et al, 2019), although this release is slower in temperate climates compared to tropical ones (Gladstone-Gallagher et al, 2014a).…”

Karakteristik Lingkungan dan Kondisi Fauna Makrobentik Di Kawasan Reboisasi Mangrove Pulau Pramuka, Panggang, dan Karya, Kepulauan Seribu, Indonesia <br><i>[Environmental Characteristics and Conditions of Macrobentic Fauna in the Mangrove Reforestation Area of Pramuka, Panggang, and Karya Island, Seribu Islands, Indonesia]<i>

“…Menurut Du et al, (2013) hutan mangrove memainkan peran kunci dalam menjaga keseimbangan ekologi di daerah pesisir yang dapat menyediakan habitat bagi organisme terestrial, muara maupun laut (Alongi 2002, Nagelkerken et al, 2008, Luther dan Greenberg 2009, MacKenzie dan Cormier 2012. Umumnya terdiri dari fauna bentik yang hidup di atau di bawah sedimen (Xinwei et al, 2017), berfungsi sebagai penghubung antara produsen primer dengan karnivora atas (predator), membantu dalam menguraikan materi organik dan siklus nutrisi, meningkatkan porositas sedimen (Lee 1989, Macnae 1968) serta menciptakan jalur-jalur oksigen, nutrisi, air maupun elemen lainnya supaya masuk ke dalam sedimen (Kon et al, 2011.…”