Influence of habitat complexity on fish density and species richness in structurally simple forereef seagrass meadows

2018 ◽  
Vol 61 (6) ◽  
pp. 547-557 ◽  
Author(s):  
Nina Ann Jin Ho ◽  
Jillian Lean Sim Ooi ◽  
Yang Amri Affendi ◽  
Ving Ching Chong
Keyword(s):  
Species Richness ◽  
Habitat Complexity ◽  
Fish Assemblages ◽  
Fish Habitat ◽  
Relative Size ◽  
Shoot Density ◽  
Fish Density ◽  
Percent Cover ◽  
Seagrass Meadows ◽  
Fish Habitats

Abstract Seagrass meadows are highly productive habitats that support commercially and ecologically important fishes and invertebrates. However, evidence of fish-habitat relationships are seldom drawn from forereef seagrass meadows that are structurally simple in terms of species richness and relative size and, consequently, their role as habitats is unclear. In this study, fish-habitat relationships were examined in such meadows in the forereef seagrasses of Tinggi Island and Babi Besar Island, Malaysia, by documenting habitat complexity attributes (canopy height, shoot density and percent cover), distance to adjacent coral reefs, and water depth within 2×2 m quadrats. Fish assemblages were recorded using the Remote Underwater Video Station method. A total of 1166 individuals from 86 taxa were found and enumerated. This study showed that (1) fish density and species richness were significantly associated with seagrass percent cover alone; (2) commercially important carnivores formed the majority of the fish populations in the meadows, and (3) fish density and species richness were positively correlated with distance to the nearest adjacent coral reef, indicating the need to account for the effects of neighboring habitats in studies of this nature. Thus, structurally simple seagrass meadows are still important fish habitats, especially as feeding grounds for commercially significant carnivores.

Tropical seaweed beds as important habitats for juvenile fish

2017 ◽  
Vol 68 (10) ◽  
pp. 1921 ◽  
Author(s):  
S. A. Tano ◽  
M. Eggertsen ◽  
S. A. Wikström ◽  
C. Berkström ◽  
A. S. Buriyo ◽  
...  
Keyword(s):  
Fish Species ◽  
Fish Assemblages ◽  
Fish Habitat ◽  
Juvenile Fish ◽  
Visual Census ◽  
Seagrass Meadows ◽  
Commercially Important ◽  
Fish Habitats ◽  
Habitat Variables

Seaweed beds within tropical seascapes have received little attention as potential fish habitat, despite other vegetated habitats, such as seagrass meadows and mangroves, commonly being recognised as important nurseries for numerous fish species. In addition, studies of vegetated habitats rarely investigate fish assemblages across different macrophyte communities. Therefore, the aim of the present study was to investigate the role of tropical seaweed beds as fish habitat, particularly for juvenile fish, by comparing their fish assemblages with those of closely situated seagrass beds. Fish assemblages were assessed by visual census in belt transects, where fish were identified and their length estimated, and habitat variables were estimated for each transect. The abundance of juvenile fish in seaweed beds was twice as high as that in seagrass meadows, whereas there was no difference in total, subadult or adult fish abundance. In addition, the abundance of commercially important and coral reef-associated juveniles was higher in seaweed beds, as was fish species richness. Fish assemblages differed between habitats, with siganids being more common in seagrass meadows and juvenile Labridae and Serranidae more common in seaweed beds. These results highlight that tropical seaweed beds are important juvenile fish habitats and underscore the need to widen the view of the shallow tropical seascape.

scholarly journals Tropical rhodolith beds are a major and belittled reef fish habitat

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Rodrigo L. Moura ◽  
Maria L. Abieri ◽  
Guilherme M. Castro ◽  
Lélis A. Carlos-Júnior ◽  
Pamela M. Chiroque-Solano ◽  
...  
Keyword(s):  
Reef Fish ◽  
Trophic Structure ◽  
Fish Assemblages ◽  
Fish Habitat ◽  
Reef Fishes ◽  
Marine Biodiversity ◽  
Resources Management ◽  
Abundance And Distribution ◽  
Fish Habitats ◽  
Energy Pathways

AbstractUnderstanding habitat-level variation in community structure provides an informed basis for natural resources’ management. Reef fishes are a major component of tropical marine biodiversity, but their abundance and distribution are poorly assessed beyond conventional SCUBA diving depths. Based on a baited-video survey of fish assemblages in Southwestern Atlantic’s most biodiverse region we show that species composition responded mainly to the two major hard-bottom megahabitats (reefs and rhodolith beds) and to the amount of light reaching the bottom. Both megahabitats encompassed typical reef fish assemblages but, unexpectedly, richness in rhodolith beds and reefs was equivalent. The dissimilar fish biomass and trophic structure in reefs and rhodolith beds indicates that these systems function based on contrasting energy pathways, such as the much lower herbivory recorded in the latter. Rhodolith beds, the dominant benthic megahabitat in the tropical Southwestern Atlantic shelf, play an underrated role as fish habitats, and it is critical that they are considered in conservation planning.

scholarly journals Seagrass Structural Traits Drive Fish Assemblages in Small-Scale Fisheries

2021 ◽  
Vol 8 ◽  
Author(s):  
Benjamin L. Jones ◽  
Lina M. Nordlund ◽  
Richard K. F. Unsworth ◽  
Narriman S. Jiddawi ◽  
Johan S. Eklöf
Keyword(s):  
Species Richness ◽  
Species Diversity ◽  
Fish Assemblages ◽  
Human Impacts ◽  
Structural Complexity ◽  
Tropical Fish ◽  
Small Scale ◽  
Seagrass Species ◽  
Seagrass Meadows ◽  
Seagrass Cover

Seagrasses – a group of foundation species in coastal ecosystems – provide key habitat for diverse and abundant faunal assemblages and support numerous ecosystem functions and services. However, whether the habitat role of seagrasses is influenced by seagrass diversity, by dominant species or both, remains unclear. To that end, we sought to investigate the specific seagrass characteristics (e.g., species diversity, seagrass traits) that influence tropical fish assemblages, and place this in the context of small-scale fishery use. We surveyed seagrass variables at 55 plots, nested within 12 sites around Zanzibar (Tanzania) in the Western Indian Ocean, and used Baited Remote Underwater Video (BRUV) systems to assess fish assemblages across plots. Using linear mixed models, we reveal that seagrass structural complexity and depth were the best predictors of fish abundance, with higher abundance occurring in deeper meadows or meadows with high canopy, leaf length and number of leaves per shoot. Moreover, an interaction between seagrass cover and land-use was the best predictor of fish species richness, where sites closer to human impacts were less affected by cover than sites with lower human impact. Overall, models with seagrass species richness or functional diversity as predictors poorly explained fish assemblages. Fish taxa that were important for small-scale fishery sectors (e.g., emperors, snappers, rabbitfish, and parrotfish) were primarily driven by seagrass structural complexity. Our results provide a unique analysis of the relationship between seagrass habitat and its associated fish assemblages in that we show that seagrass species diversity had little effect on seagrass fish assemblages, which instead appear driven by specific seagrass traits and seagrass cover. If conserving high value species that support adjacent fisheries is the priority for protecting seagrass meadows, then seagrass areas should be chosen with high cover and structural complexity that are in deeper waters. Any conservation measures also need to balance the needs of fishers that use the resources supported by seagrasses.

scholarly journals Dynamics of fish assemblages on a continuous rocky reef and adjacent unconsolidated habitats at Fernando de Noronha Archipelago, tropical western Atlantic

2011 ◽  
Vol 9 (4) ◽  
pp. 869-879 ◽  
Author(s):  
Paulo R. Medeiros ◽  
Ricardo S. Rosa ◽  
Ronaldo B. Francini-Filho
Keyword(s):  
Species Richness ◽  
Spatial Variation ◽  
Reef Fish ◽  
Fish Assemblages ◽  
Fish Abundance ◽  
Coralline Algae ◽  
Rocky Reef ◽  
Percent Cover ◽  
Western Atlantic ◽  
Bare Rock

In recent years, many studies investigated how density-dependent factors, such as shortages in microhabitat and food availability influence the structure of reef fish assemblages. Most of what is currently known, however, comes from comparisons of isolated patch reefs and from correlations between fish abundance and one or few microhabitat variables. In addition, most studies were done in the Caribbean and Indo-Pacific regions, whereas the South Atlantic region has been, to date, understudied. The present study evaluated spatial and temporal variations in reef fish abundance and species richness in a continuous rocky reef and adjacent unconsolidated habitats in a Southwestern Atlantic reef, using underwater techniques to assess both fish numbers and microhabitat variables (depth, rugosity, number of crevices and percent cover of live benthic organisms, bare rock, sand, and limestone). Higher species richness was observed at consolidated substratum stations on both sampling periods (May and October), but fish abundance did not show a significant spatial variation. Topographical complexity and percent cover of algae (except coralline algae) were amongst the most important determinants of species richness, and correlations between fish size and refuge crevice size were observed. The non-random patterns of spatial variation in species richness, and to a lesser extent, fish abundance, were related to differences in substratum characteristics and the inherent characteristics of fishes (i.e. habitat preferences) and not to geographical barriers restraining fish movement. This study highlights the importance of concomitantly assessing several microhabitat variables to determine their relative influence in reef fish assemblages.

scholarly journals Demersal Fish Assemblages in NE Atlantic Seagrass and Kelp

Diversity ◽  
2020 ◽  
Vol 12 (10) ◽  
pp. 366
Author(s):  
Evie Furness ◽  
Richard K.F. Unsworth
Keyword(s):  
Species Richness ◽  
Fish Assemblages ◽  
Demersal Fish ◽  
Kelp Forests ◽  
Evidence Based ◽  
Ecological Value ◽  
Commercial Fish ◽  
Seagrass Meadows ◽  
The North ◽  
Commercial Species

Global fisheries are in decline, calling for urgent evidence-based action. One such action is the identification and protection of fishery-associated habitats such as seagrass meadows and kelp forests, both of which have suffered long-term loss and degradation in the North Atlantic region. Direct comparisons of the value of seagrass and kelp in supporting demersal fish assemblages are largely absent from the literature. Here, we address this knowledge gap. Demersal fish were sampled using a baited camera to test for differences between habitats in (1) the species composition of the fish assemblages, (2) the total abundance and species richness of fishes, and (3) the abundances of major commercial species. Seagrass and kelp-associated fish assemblages formed two significantly distinct groupings, which were driven by increased whiting (Merlangius merlangus) and dogfish (Scyliorhinus canicula) presence in seagrass and higher abundances of pollock (Pollachius pollachius) and goby (Gobiusculus flavescens) in kelp. The abundance, diversity, and species richness did not change significantly between the two habitats. We conclude that seagrass and kelp do support unique demersal fish assemblages, providing evidence that they have different ecological value through their differing support of commercial fish species. Thus, this study improves the foundation for evidence-based policy changes.

Seagrass meadows shape fish assemblages across estuarine seascapes

2018 ◽  
Vol 588 ◽  
pp. 179-189 ◽  
Author(s):  
BL Gilby ◽  
AD Olds ◽  
RM Connolly ◽  
PS Maxwell ◽  
CJ Henderson ◽  
...  
Keyword(s):  
Fish Assemblages ◽  
Seagrass Meadows

scholarly journals Biodiversity hanging by a thread: the importance of fungal litter-trapping systems in tropical rainforests

2011 ◽  
Vol 8 (3) ◽  
pp. 397-400 ◽  
Author(s):  
Jake L. Snaddon ◽  
Edgar C. Turner ◽  
Tom M. Fayle ◽  
Chey V. Khen ◽  
Paul Eggleton ◽  
...  
Keyword(s):  
Species Richness ◽  
Leaf Litter ◽  
Plant Diversity ◽  
Habitat Complexity ◽  
Tropical Rainforests ◽  
Dramatic Reduction ◽  
Experimental Removal ◽  
Crucial Component ◽  
High Species Richness ◽  
Vital Resource

The exceptionally high species richness of arthropods in tropical rainforests hinges on the complexity of the forest itself: that is, on features such as the high plant diversity, the layered nature of the canopy and the abundance and the diversity of epiphytes and litter. We here report on one important, but almost completely neglected, piece of this complex jigsaw—the intricate network of rhizomorph-forming fungi that ramify through the vegetation of the lower canopy and intercept falling leaf litter. We show that this litter-trapping network is abundant and intercepts substantial amounts of litter (257.3 kg ha −1 ): this exceeds the amount of material recorded in any other rainforest litter-trapping system. Experimental removal of this fungal network resulted in a dramatic reduction in both the abundance (decreased by 70.2 ± 4.1%) and morphospecies richness (decreased by 57.4 ± 5.1%) of arthropods. Since the lower canopy levels can contain the highest densities of arthropods, the proportion of the rainforest fauna dependent on the fungal networks is likely to be substantial. Fungal litter-trapping systems are therefore a crucial component of habitat complexity, providing a vital resource that contributes significantly to rainforest biodiversity.

Cyprinid distributions in Northeast U.S.A. lakes: evidence of regional-scale minnow biodiversity losses

1997 ◽  
Vol 54 (7) ◽  
pp. 1593-1607 ◽  
Author(s):  
T R Whittier ◽  
D B Halliwell ◽  
S G Paulsen
Keyword(s):  
New York ◽  
Species Richness ◽  
New England ◽  
Fish Assemblages ◽  
Regional Scale ◽  
Median Number ◽  
Southern New England ◽  
Sample Data ◽  
Golden Shiner ◽  
Northern New England

Fish assemblages were sampled in 195 randomly selected lakes in the northeastern United States during the summers of 1991-1994. Most lakes in northern Maine had three to seven minnow species, constituting 40-80% of species in each lake. Lakes in New Jersey, southern New York, and southern New England rarely had minnows, other than golden shiner (Notemigonus crysoleucas). Lakes in the Adirondacks and the remainder of northern New England had intermediate numbers. We examined minnow native ranges and autecology and evaluated species richness related to littoral predators and human disturbance. Sample data suggested alteration in the minnow assemblages over much of the region. The most consistent factor related to minnow species richness was the presence of littoral predators. Median number of minnow species was two in lakes lacking predators and zero in lakes with predators. Non-native predators, especially Micropterus spp., have been introduced throughout the Northeast; 69% of the sampled lakes had non-native predators. In the absence of predators, minnow species declined with increased human activity in the watershed and along lake shorelines. Only in northern Maine did lake minnow assemblages seem relatively intact.

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