Epibenthic community structure in Port Phillip Bay, Victoria, Australia

2000 ◽  
Vol 51 (7) ◽  
pp. 689 ◽  
Author(s):  
Brian F. Cohen ◽  
David R. Currie ◽  
Matthew A. McArthur

Epibenthic community structure in Port Phillip Bay was examined from quantitative diver samples collected at 30 depth-stratified stations during 1998. Analysis of variance showed a strong trend of decreasing epibenthic abundance, biomass and species diversity with depth. Reductions in these three parameters were most pronounced over shallow inshore waters and could be attributed largely to decreases in the abundance of the heavy, mat-forming ascidian Pyura stolonifera with depth. Four epifaunal community groupings, closely reflecting differences in sediment and habitat type within the bay, were identified from ordinations of species abundance and biomass data. The four epifaunal groupings also closely matched distributional patterns observed in other studies in both demersal fish and infaunal communities. Epifaunal communities in the bay were dominated by filter-feeding organisms which accounted for nearly 95% of the total species abundance and 98% of the total species biomass. Seven of the 63 epibenthic organisms collected during the survey are exotic introductions to the bay (Sabella spallanzanii, Ascidiella aspersa, Styela clava, Styela plicata, Ciona intestinalis, Pyromaia tuberculata and Asterias amurensis). As many of these species are widespread and abundant (35% of all individuals), their effects on the ecology of Port Phillip Bay are likely to be significant.

2020 ◽  
Vol 637 ◽  
pp. 159-180
Author(s):  
ND Gallo ◽  
M Beckwith ◽  
CL Wei ◽  
LA Levin ◽  
L Kuhnz ◽  
...  

Natural gradient systems can be used to examine the vulnerability of deep-sea communities to climate change. The Gulf of California presents an ideal system for examining relationships between faunal patterns and environmental conditions of deep-sea communities because deep-sea conditions change from warm and oxygen-rich in the north to cold and severely hypoxic in the south. The Monterey Bay Aquarium Research Institute (MBARI) remotely operated vehicle (ROV) ‘Doc Ricketts’ was used to conduct seafloor video transects at depths of ~200-1400 m in the northern, central, and southern Gulf. The community composition, density, and diversity of demersal fish assemblages were compared to environmental conditions. We tested the hypothesis that climate-relevant variables (temperature, oxygen, and primary production) have more explanatory power than static variables (latitude, depth, and benthic substrate) in explaining variation in fish community structure. Temperature best explained variance in density, while oxygen best explained variance in diversity and community composition. Both density and diversity declined with decreasing oxygen, but diversity declined at a higher oxygen threshold (~7 µmol kg-1). Remarkably, high-density fish communities were observed living under suboxic conditions (<5 µmol kg-1). Using an Earth systems global climate model forced under an RCP8.5 scenario, we found that by 2081-2100, the entire Gulf of California seafloor is expected to experience a mean temperature increase of 1.08 ± 1.07°C and modest deoxygenation. The projected changes in temperature and oxygen are expected to be accompanied by reduced diversity and related changes in deep-sea demersal fish communities.


2021 ◽  
Vol 6 (3) ◽  
pp. 67328
Author(s):  
Nur Apriatun Nafisah ◽  
R.C.Hidayat Soesilohadi

Petungkriyono forest is a tropical rainforest with high biodiversity. The increasing tourism activities in Petungkriyono lead to land conversion. Dragonfly (order Odonata) is a good bioindicator for aquatic and terrestrial. This study aimed to compare the community structure of Odonata in natural forests and tourist sites. The method of collecting imago Odonata was done by direct searching, samples were captured using sweep netting. The results showed that the dragonflies found in all locations consisted of the same family, 2 families (Gomphidae and Libellulidae) from the suborder Anisoptera and 6 families (Calopterygidae, Chlorocyphidae, Coenagrionidae, Euphaidae Platycnemididae, and Platystictidae) from the suborder Zygoptera. The total species of dragonflies found in Sokokembang were 15 species with a total of 293 individuals, Tirta Muncar 13 species of 287 individuals, Karanggondang 17 species of 276 individuals, and Curug Lawe 14 species of 242 individuals. The highest relative abundance of individuals was in the natural forest of Sokokembang is Drepanosticta spatulifera (26.28%) and in Karanggondang Vestalis luctuosa (24.64%), while in the tourist forests of Tirta Muncar and Curug Lawe were Euphaea variegata (34.84% and 28.51 %). The structure of the Odonata community is based on the Shannon-Wiener diversity index in the natural forests of Sokokembang (2.18) and Karanggondang (2.21) at the tourist sites of Tirta Muncar (1.84) and Curug Lawe (2.11). The results showed that the structure of the Odonata community based on the level of the diversity index value, evenness index, and dominance index in natural forests and tourist sites in Petungkriyono forest was not significantly different. 


2008 ◽  
Vol 24 (4) ◽  
pp. 445-455 ◽  
Author(s):  
Laura T. van Ingen ◽  
Ricardo I. Campos ◽  
Alan N. Andersen

AbstractIn mixed tropical landscapes, savanna and rain-forest vegetation often support contrasting biotas, and this is the case for ant communities in tropical Australia. Such a contrast is especially pronounced in monsoonal north-western Australia, where boundaries between rain forest and savanna are often extremely abrupt. However, in the humid tropics of north-eastern Queensland there is often an extended gradient between rain forest and savanna through eucalypt-dominated tall open forest. It is not known if ant community structure varies continuously along this gradient, or, if there is a major disjunction, where it occurs. We address this issue by sampling ants at ten sites distributed along a 6-km environmental gradient from rain forest to savanna, encompassing the crest and slopes of Mt. Lewis in North Queensland. Sampling was conducted using ground and baited arboreal pitfall traps, and yielded a total of 95 ant species. Mean trap species richness was identical in rain forest and rain-forest regrowth, somewhat higher in tall open forest, and twice as high again in savanna woodland. The great majority (78%) of the 58 species from savanna woodland were recorded only in this habitat type. MDS ordination of sites based on ant species composition showed a continuum from rain forest through rain-forest regrowth to tall open forest, and then a discontinuity between these habitat types and savanna woodland. These findings indicate that the contrast between rain forest and savanna ant communities in tropical Australia is an extreme manifestation of a broader forest-savanna disjunction.


2021 ◽  
Vol 9 (12) ◽  
pp. 1353
Author(s):  
Guillermo Figueroa-Muñoz ◽  
Carlos Molinet ◽  
Manuel Díaz ◽  
Patricio De los Ríos-Escalante

The southern king crab, Lithodes santolla, is an important fishery resource in the inner seas of Chilean Patagonia. The fishing gear used to catch southern king crab (bait trap) and its operation at different depths over several months provide the opportunity to gather information about relative abundance. The aim of the present study was to analyze the information collected from the catches of southern king crab and its associated fauna in the Magdalena Fjord to study the biodiversity and ecology of scavenging decapod crustaceans. Specifically, the study aimed to determine the bathymetric patterns of abundance by species, to model the abundance by season (winter and spring) and to determine the structuring pattern of scavenging decapods assemblage. Samples were collected between June and November 2019 by deploying traps in four bathymetric strata: 1 = 0–50 m; 2 = 51–100 m; 3 =101–150 m; 4 = 151–200 m. We registered a total of 673 decapod specimens associated with the southern king crab fishery, representing five species: Lithodes santolla (n = 96), Libidoclaea smithii (n = 10), Metacarcinus edwardsii (n = 58), Munida gregaria (n = 507) and Peltarion spinulosum (n = 2). The abundance of decapod species varied by month and bathymetric strata. We found bathymetric patterns for L. santolla abundance, M. gregaria, M. edwardsii, and total species abundance. The most informative model to explain scavenging decapod abundance by generalized linear model (GLM) included species and season. The null model of species co-occurrence analysis revealed that all species associations during the sampled months were random. Our study is the first that provides evidence about patterns of bathymetrical and temporal variation of scavenging decapod abundance and expands the body of knowledge regarding the biodiversity of scavenger decapods in the Magdalena Sound.


1998 ◽  
Vol 46 (2) ◽  
pp. 93-109 ◽  
Author(s):  
Gecely R. A. Rocha ◽  
Carmen L. D. B. Rossi-Wongtschowski

Fluctuations in the distribution and abundance of demersal fishes collected by otter trawl on the continental shelf of Ubatuba were examined over a two-year sampling period, in an area up to 50 m depth. A total of 111 species were collected. Seasonal and annual fluctuations in species abundance were related to differences in the distribution of Coastal Water and South Atlantic Central Water masses. The demersal fish fauna in the area was divided into three ecologically distinct communities: Tropical Sciaenid, Subtropical Sciaenid, and Gerreid-Haemulid. The most important one is the Tropical Sciaenid Community, characterized by Ctenosciaena gracilicirrhus, Paralonchurus brasiliensis, and Cynoscion jamaicensis.


2019 ◽  
Vol 51 (2) ◽  
pp. 193-200 ◽  
Author(s):  
Yiping Niu ◽  
Guodong Ren ◽  
Giulia Lin ◽  
Letizia Di Biase ◽  
Simone Fattorini

Tenebrionids are a conspicuous faunal component of Central Asian deserts, but little is known about their community ecology. We investigated how tenebrionid community structure varied along a vegetational gradient in the Ulan Buh Desert (Gobi Desert). Sampling was done with pitfall traps in three sites with different vegetation cover. Species abundance distributions were fitted by the geometric series model, which expresses the “niche pre-emption” hypothesis. Community structure was investigated using different measures of diversity (number of species, Margaleff richness and Shannon-Weaner index), dominance (Simpson and Berger-Parker indexes) and evenness (Pielou’s index). The observed tenebrionid species richness was similar to that known from other Gobi Desert sites. The three investigated sites have similar species-abundance patterns, but the most dominant species varied among them. This suggests that the local environment operates a filtering action on the same basic fauna, allowing different species to dominate under different conditions. Overall, the highest total abundance was observed in the true desert site, however this site had a community structure similar to that observed in the site with more vegetation. By contrast, the investigated site with intermediate conditions showed a higher diversity and evenness, and a lower dominance. Thus, intermediate conditions of plant cover favour tenebrionid diversity, whereas a dense cover or a very sparse cover increases the dominance.


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