Variation in structural attributes of patch-forming corals and in patterns of abundance of associated fishes

2002 ◽  
Vol 53 (7) ◽  
pp. 1045 ◽  
Author(s):  
Sally J. Holbrook ◽  
Andrew J. Brooks ◽  
Russell J. Schmitt

There is increasing evidence that some of the spatial variation in characteristics of local assemblages of reef fish can be explained by variation in measurable features of the habitat. At Moorea, French Polynesia, several species of the coral genus Porites form patch reefs and provide an important source of habitat structure within the lagoons. One species, Porites rus, forms structurally complex patch reefs with surface branches and numerous holes and interior cavities. In contrast, reefs composed of colonies of Porites lobata-like species are less complex; they always lack branches and interior cavities and frequently lack holes. Surveys of these reefs revealed that, as expected, abundance and species richness of fish scaled with the size of the patch reef. However, for a given size, P. rus reefs had significantly higher species richness and overall abundance than P. lobata reefs. Further, abundances of fish, at the family level, varied among sets of reefs that had different combinations of key shelter microhabitats (i.e. holes, cavities, branches). This variation in relative abundances of fish families was predictable based on the microhabitat-use patterns of the fish; the greater the utilization of a microhabitat when available, the greater the difference in abundance between those reefs and others that lacked that microhabitat. Thus, spatial variation in the structure of the fish assemblages was strongly associated with variation among the types of patch-forming corals in the variety of microhabitat features each provided.

2013 ◽  
Vol 93 (8) ◽  
pp. 2265-2272 ◽  
Author(s):  
Akihisa Hattori ◽  
Takuro Shibuno

In local reef fish communities, species richness increases with increasing reef area. At Ishigaki Island, Japan, species richness is much lower on large reefs in the shallow back reef than that expected from random placement model simulations (RPMS). As three aggressive territorial herbivorous damselfish, Stegastes nigricans, Stegastes lividus and Hemiglyphidodon plagiometopon, coexist only on such large reefs, we focused on these species and examined patterns of their distribution and abundance on 84 patch reefs of various sizes (area and height). We also examined their aggressive intra- and interspecific behavioural interactions and habitat use on the two large reefs (the largest complex patch reef and the large flat patch reef) among the 84 patch reefs. While the abundance of both S. lividus and H. plagiometopon was highly correlated with patch reef area, that of S. nigricans was closely correlated with patch reef height. For S. nigricans and S. lividus, interspecific interactions occurred significantly more frequently than intraspecific interactions on the large flat patch reef. However, there was no significant difference in frequencies of the two interaction types on the largest complex patch reef, where they three-dimensionally segregated conspecific territories. This study suggested that reef height as well as reef area influence the distribution and abundance of these territorial herbivorous damselfish in the shallow back reef. As large patch reefs cannot be tall allometrically in shallow back reefs, relatively flat patch reefs may not have the high species richness expected from RPMS based on reef area.


2011 ◽  
Vol 9 (4) ◽  
pp. 869-879 ◽  
Author(s):  
Paulo R. Medeiros ◽  
Ricardo S. Rosa ◽  
Ronaldo B. Francini-Filho

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.


2016 ◽  
Vol 283 (1844) ◽  
pp. 20160128 ◽  
Author(s):  
Stéphanie D'agata ◽  
Laurent Vigliola ◽  
Nicholas A. J. Graham ◽  
Laurent Wantiez ◽  
Valeriano Parravicini ◽  
...  

High species richness is thought to support the delivery of multiple ecosystem functions and services under changing environments. Yet, some species might perform unique functional roles while others are redundant. Thus, the benefits of high species richness in maintaining ecosystem functioning are uncertain if functions have little redundancy, potentially leading to high vulnerability of functions. We studied the natural propensity of assemblages to be functionally buffered against loss prior to fishing activities, using functional trait combinations, in coral reef fish assemblages across unfished wilderness areas of the Indo-Pacific: Chagos Archipelago, New Caledonia and French Polynesia. Fish functional diversity in these wilderness areas is highly vulnerable to fishing, explained by species- and abundance-based redundancy packed into a small combination of traits, leaving most other trait combinations (60%) sensitive to fishing, with no redundancy. Functional vulnerability peaks for mobile and sedentary top predators, and large species in general. Functional vulnerability decreases for certain functional entities in New Caledonia, where overall functional redundancy was higher. Uncovering these baseline patterns of functional vulnerability can offer early warning signals of the damaging effects from fishing, and may serve as baselines to guide precautionary and even proactive conservation actions.


2010 ◽  
Vol 56 (6) ◽  
pp. 670-677 ◽  
Author(s):  
Yunzhi Yan ◽  
Shan He ◽  
Ling Chu ◽  
Xiuying Xiang ◽  
Yanju Jia ◽  
...  

Abstract Spatial and temporal variation of fish assemblages were investigated seasonally from May 2007 to February 2008 across 11 study sites in a subtropical small stream, the Puxi Stream, of the Huangshan Mountain. Along the longitudinal gradient from headwater to downstream, fish species richness and abundance increased gradually, but then decreased significantly at the lower reaches. The highest species richness and abundance were observed in August and the lowest in February. Based on analysis of similarities (ANOSIM), fish assemblages were significantly different in spatial variation but not in temporal variation. Although differences were observed both among sites and among stream orders, the lower R value in order-variation suggested stream order was not the optimal factor explaining the spatial variation of fish assemblages. In addition, dam construction did not significantly alter fish assemblages in the sites adjacent to and immediately downstream to dams. Using cluster analysis and non-metric Multi Dimensional Scaling analysis (NMS), assemblages were separated into three groups at a Bray-Curtis similarity value of 42%: the upper, middle and lower groups. Following analysis of similarity percentages of species contributions (SIMPER), shifts in occurrence or abundance of S. curriculus, Z. platypus, R. bitterling and A. fasciatus contributed most to the differences amongst the three groups. Standard Deviation Redundancy Analysis (RDA) suggested that habitat structure (such as elevation, substrate, and flow velocity) contributed to the spatial and temporal pattern of fish assemblages in the Puxi Stream. In conclusion, the fish assemblages in Puxi Stream presented significant spatial but not temporal variation. Human disturbance has perhaps induced the decrease in species diversity in the lower reaches. However, no significant change was observed for fish assemblages in sites far from and immediately downstream from low-head dams.


2008 ◽  
Vol 54 (No. 4) ◽  
pp. 189-193
Author(s):  
M. Żmihorski

Clearcuts are one of the results of forest management. The aim of this study was to assess the effect of clearcuts on bird communities in a managed forest in Western Poland. I applied the method of point transect counts. 20 points were located near clearcuts (less than 100 m from the nearest clearcut) and 25 points in the forest interior. In total, 36 bird species were recorded. On average, I found 9.20 bird species at points located near clearcuts and 6.72 species at points situated in the forest interior, and the difference was significant. The cumulative number of bird species for a given number of sampling points in the vicinity of clearcuts was higher than in the forest interior. The obtained results indicate that in managed, even-aged forests the generation of clearcuts can lead to an increase in local bird species richness.


1997 ◽  
Vol 54 (7) ◽  
pp. 1593-1607 ◽  
Author(s):  
T R Whittier ◽  
D B Halliwell ◽  
S G Paulsen

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.


2016 ◽  
Vol 8 (3) ◽  
pp. 434-442
Author(s):  
Jing Wu ◽  
Jianqiang Qian ◽  
Xianzhang Hou ◽  
Carlos A. Busso ◽  
Zhimin Liu ◽  
...  

2020 ◽  
Vol 21 (5) ◽  
Author(s):  
M Munasik ◽  
AGUS SABDONO ◽  
AZELIA N. ASSYFA ◽  
DIAH PERMATA WIJAYANTI ◽  
SUGIYANTO SUGIYANTO ◽  
...  

Abstract. Munasik, Sabdono A, Assyfa AN, Wijayanti DP, Sugiyanto, Irwani, Pribadi R. 2020. Coral transplantation on a multilevel substrate of Artificial Patch Reefs: effect of fixing methods on the growth rate of two Acropora species. Biodiversitas 21: 1816-1822. Branching Acropora is generally used in coral transplantation to rehabilitate coral reefs. However, these corals are sensitive to environmental changes. Artificial Patch Reef  (APR) is an artificial structure that provides a multilevel hard substrate. The purpose of the study was to investigate the effectiveness of the APR structure to facilitate the growth and survival of Acropora branching. Two species Acropora aspera and Acropora copiosa were transplanted vertically and horizontally on a modular concrete block in different levels of APR situated in the shallow reef of Panjang Island, Central Java. The results showed that the coral growth rate varied from 96.7 to 346.9 cm3/month, while survival ranged from 30 to 100% after 8 months. Lower survival rate mostly was found in the upper level of APR. The statistical analyses showed that the growth rate of A. copiosa fragment was significantly higher than that of A. aspera  (p<0.05). Moreover, there were also significant differences in the treatments of transplantation method  (p<0.05) to enhance coral growth. However, multilevel substrates were not significantly influenced by coral growth. This study suggested that A. copiosa which has high-level complexity in branching pattern will be selected to apply in shallow reef rehabilitation with transplanted vertically.


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