Spatio-temporal dynamics of fish feeding in the lower Mulgrave River, north-eastern Queensland: the influence of seasonal flooding, instream productivity and invertebrate abundance

2009 ◽  
Vol 60 (2) ◽  
pp. 97 ◽  
Author(s):  
Thomas S. Rayner ◽  
Bradley J. Pusey ◽  
Richard G. Pearson
Keyword(s):  
Habitat Structure ◽  
Fish Community ◽  
Temporal Dynamics ◽  
Fish Habitat ◽  
Habitat Model ◽  
Trophic Dynamics ◽  
Gut Contents ◽  
Wet Season ◽  
Littoral Invertebrates ◽  
Spatio Temporal

Wet-season flooding causes dietary shifts in tropical freshwater fish by regulating instream productivity, habitat structure and food availability. These dynamics have been comprehensively documented worldwide, but data are limited for Australia’s Wet Tropics rivers. The aim of the present study was to extend our earlier fish–habitat model for these systems by examining the role of trophic dynamics in determining fish assemblage composition. Chlorophyll a and phaeophytin concentrations, benthic and littoral invertebrates and fish were collected at four sites in the lower Mulgrave River under a range of flow conditions. Wet-season flooding caused significant reductions in instream productivity, whereas habitat disturbance reduced densities and abundances of littoral and benthic invertebrates. However, volumetric gut contents of 1360 fish, from 36 species, revealed seasonal shifts in guild membership by only two species, with fish moving between sites to target their preferred prey items – largely irrespective of differences in habitat structure. As a result, the food consumed by the fish community present at each site closely reflected the seasonal availability of food resources. The present paper questions whether fish community composition in small tropical rivers can be accurately predicted from habitat surrogates alone and encourages consideration of constraints imposed by the trophic dynamics and reproductive ecology of fish.

scholarly journals Seasonal flooding, instream habitat structure and fish assemblages in the Mulgrave River, north-east Queensland: towards a new conceptual framework for understanding fish-habitat dynamics in small tropical rivers

2008 ◽  
Vol 59 (2) ◽  
pp. 97 ◽  
Author(s):  
Thomas S. Rayner ◽  
Bradley J. Pusey ◽  
Richard G. Pearson
Keyword(s):  
Habitat Structure ◽  
Fish Assemblages ◽  
Fish Habitat ◽  
Dry Season ◽  
Assemblage Structure ◽  
Tropical Rivers ◽  
Wet Season ◽  
Seasonal Flooding ◽  
North East ◽  
Habitat Dynamics

Strong relationships between seasonal flooding, instream habitat structure and fish assemblages have been well documented in large tropical rivers (e.g. the flood pulse concept). However, the mechanics of these relationships are likely to differ substantially in smaller coastal rivers, such as those in Costa Rica, south-east Brazil and Australia’s Wet Tropics. These systems typically feature steep upland streams with short, deeply incised lowland channels and poorly connected floodplains. This hypothesis was investigated by documenting spatial and temporal variation in fish-habitat relationships in the Mulgrave River, north-east Queensland. Sampling was conducted at four lowland sites under a range of flow conditions, from dry-season baseflows to a one-in-ten-year flood. Longitudinal environmental gradients and fine-scale habitat patches were important in regulating fish assemblage structure during the dry season. However, high wet-season flows, constrained by the deep channel, acted as disturbances rather than gentle flood-pulses. In particular, the mobilisation of bed sediments led to scouring of aquatic vegetation and a dramatic reduction in habitat heterogeneity. Seasonal movements of fish led to significant changes in assemblage structure – from a community dominated by Neosilurus ater, Hypseleotris compressa, Awaous acritosus and Redigobius bikolanus during the dry season, to one dominated by Nematalosa erebi, Ambassis agrammus and Glossamia aprion during the wet season. Based on these observations, together with information from the literature, a conceptual model of fish-habitat dynamics is presented that is better suited to small tropical rivers than those developed in larger systems with expansive floodplains.

scholarly journals Ekologi Trofik Komunitas Ikan di Perairan Segara Menyan, Subang, Jawa Barat (Trophic Ecology of the Fish Community in Segara Menyan Coastal Lagoon, Subang, West Java)

2015 ◽  
Vol 20 (3) ◽  
pp. 170 ◽  
Author(s):  
Ahmad Zahid ◽  
M.F. Rahardjo ◽  
Lenny S Syafei ◽  
Rini Susilowati
Keyword(s):  
Temporal Variation ◽  
Fish Species ◽  
Trophic Level ◽  
Coastal Lagoon ◽  
Fish Community ◽  
Trophic Ecology ◽  
Diet Breadth ◽  
Gut Contents ◽  
Trophic Guild ◽  
Spatio Temporal

Pengetahuan mengenai ekologi trofik merupakan dasar dalam memahami ekosistem secara keseluruhan yang dapat dijelaskan melalui pola hubungan trofik interspesies ataupun interserikat. Penelitian bertujuan untuk menjelaskan ekologi trofik meliputi indeks trofik dan jenis makanan dominan, serikat dan tingkat trofik, dan variasi spasial dan temporal komunitas ikan di estuari Segara Menyan. Pengambilan ikan contoh dilakukan setiap bulan pada zona berbeda. Ikan contoh dipisahkan berdasarkan waktu dan lokasi pengamatan, dianalisis isi saluran pencernaannya. Analisa data meliputi indeks vakuitas, jumlah total organisme makanan, jenis makanan dominan, luas relung makanan, dan tingkat trofik.  Pada pengamatan 106 spesies ikan, sebanyak 1-380 saluran pencernaan ikan diamati. Sebanyak lima dari 106 spesies memiliki nilai indeks vakuitas “0” dan jumlah makanan yang dikonsumsi bervariasi mulai dari empat hingga 27 jenis makanan. Secara umum, luas relung ikan adalah rendah berkisar 0,20-0,78 dan kebanyakan berada pada kisaran 0,20-0,48. Zooplankton merupakan jenis makanan paling dominan dikonsumsi oleh ikan. Komunitas ikan dikelompokkan dalam tujuh serikat trofik, yaitu detritivora, fitoplanktivora, zooplanktivora, zoobentivora, moluskivora, krustasivora, dan pisivora. Tingkat trofik komunitas ikan berkisar 2,05-4,73. Faktor perubahan ontogenetik, persediaan makanan, karakteristik habitat, dan ruaya beberapa spesies ikan memengaruhi variasi spasio-temporal jejaring makanan di Segara Menyan. Kata kunci: interaksi trofik, laguna, ikan, variasi spasio-temporal, serikat trofik Knowledge of trophic ecology is one way to understanding the whole ecosystem which explained by trophic relationship pattern (interspecies or interguild). The objective research was described of the trophic ecology, i.e. trophic index and dominant prey, trophic guild and trophic level, and spatio-temporal variation of fish community in Segara Menyan coastal lagoon. Fish were collected monthly for one year at three zones. Fish samples were placed in separate labelled plastic bags according to the time scale and location sampling, then gut contents were analyzed. The data of vacuity index, number of prey, prey dominant, diet breadth, and trophic level were analyzed. For each of 106 fish species, between 1 and 380 stomachs, were examined. The vacuity index was also different among species. Five of 106 species had a vacuity index of “0” and total number of food items consumed varied between fish species, ranging from three items to 27 items. The overall diet breadth (Bi) was relatively low among species, ranging from 0.20 to 0.78, with most of them between 0.20 and 0.48. Calanoid copepods comprised the most common food item consumed by all the fishes examined. Fishes occurring can be broadly categorized into seven different trophic guilds. The trophic level of fish communities ranged from 2.05 to 4.73. Spatio-temporal variation of food web was influenced of ontogenetic shift, food availability, habitat characteristic, and migration of some species in Segara Menyan coastal lagoon. Keywords: trophic interaction, lagoon, fishes, spatio-temporal variation, trophic guild

Vegetation pattern divergence between dry and wet season in a semiarid savanna – Spatio-temporal dynamics of plant diversity in northwest Namibia

2010 ◽  
Vol 74 (11) ◽  
pp. 1516-1524 ◽  
Author(s):  
S.K. Hassler ◽  
J. Kreyling ◽  
C. Beierkuhnlein ◽  
J. Eisold ◽  
C. Samimi ◽  
...  
Keyword(s):  
Plant Diversity ◽  
Temporal Dynamics ◽  
Vegetation Pattern ◽  
Wet Season ◽  
Spatio Temporal

scholarly journals The influence of habitat on the spatio-temporal dynamics of fish assemblages in a lagoon-estuarine system of the Mexican Pacific

2020 ◽  
Vol 48 (1) ◽  
pp. 23-37
Author(s):  
Emilio I. Romero-Berny ◽  
Ernesto Velázquez-Velázquez ◽  
Juan J. Schmitter-Soto ◽  
Isaías H. Salgado-Ugarte
Keyword(s):  
Fish Assemblages ◽  
Temporal Dynamics ◽  
Fish Habitat ◽  
Habitat Associations ◽  
Estuarine System ◽  
Nursery Ground ◽  
Fish Assemblage Structure ◽  
Mexican Pacific ◽  
Spatio Temporal ◽  
Physical And Chemical

Fish assemblages change significantly with physical and chemical characteristics of water; however, their response to the variability of geomorphic habitats has been rarely evaluated in lagoon-estuarine in one of these systems of the Mexican Pacific. Spatio-temporal variation of fish assemblage structure was assessed for three habitats: lagoon, estuarine, channel and inlet. The hypothesis was that sheltered areas support comparatively higher richness and abundance of fish species, with more small-sized specimens than the most exposed areas. We found that the ichthyofauna differed significantly among habitats. Several species were smaller in the lagoon compared with the other habitats, suggesting a use of the lagoon as a nursery ground. Moreover, dominant species for the lagoon were rarely found or absent in the inlet, whereas others were found only present or with higher abundance in the inlet. Although seasonal differences in richness and composition were detected, the evidence of fish-habitat associations for many species was noticeable regardless of seasonality, probably due to a high percentage of resident species during the annual cycle. The lagoon supports a greater abundance and species richness, due to a more sheltered and structured habitat, evidencing habitat-driven segregation in fish assemblages, and an aspect that should be incorporated for management of coastal ecosystems.

scholarly journals Spatial-temporal dynamics of biome Cerrado using different vegetation indexes

2019 ◽  
pp. 1438-1446
Author(s):  
Jefferson Vieira José ◽  
Niclene Ponce Rodrigues de Oliveira ◽  
Tonny Jose de Araújo da Silva ◽  
Edna Maria Bonfim Silva ◽  
Jéfferson de Oliveira Costa ◽  
...  
Keyword(s):  
Temporal Dynamics ◽  
Vegetation Indices ◽  
Brazilian Cerrado ◽  
Wet Season ◽  
Mato Grosso ◽  
Cerrado Biome ◽  
Vegetation Indexes ◽  
Different Seasons ◽  
Spatio Temporal ◽  
Landsat Satellite

The Cerrado ranks among the major biomes in Brazil and its vegetation can now be monitored through remote sensing, although environmental factors can affect the use of this technique. Thus, the possibility of conducting a study in a region with negligible anthropogenic intrusion may become a potential reference work in controlling the spatio-temporal alterations occurring in the Cerrado biome. This study aimed at assessing the spatio-temporal dynamics of the Brazilian Cerrado biome at different seasons of the year (wet and dry), employing various vegetation indices (NDVI, SAVI, EVI and LAI) drawn from the LANDSAT satellite images 8. The study itself was conducted in the Tadarimana Indigenous reserve situated in the State of Mato Grosso, Brazil. Extending across an area of 9952 hectares, the predominant vegetation cover in this reserve include the Savanna-Seasonal Contact (84.78%) and Savanna (15.22%). The data was analyzed using descriptive statistics and the best characterization of the vegetation was identified in the regions where higher variability was observed in the responses of the vegetation indices. The LAI revealed the best performance when the spatio-temporal dynamics of the Brazilian Cerrado biome was assessed. The wet season displayed the highest values among the different vegetation indices, despite the variances.

Population dynamics of the coconut crab Birgus latro on Aldabra Atoll, Seychelles

2021 ◽  
Vol 665 ◽  
pp. 103-113
Author(s):  
JC Appoo ◽  
EF Cagua ◽  
J van de Crommenacker ◽  
AJ Burt ◽  
P Pistorius ◽  
...  
Keyword(s):  
Temporal Dynamics ◽  
Lunar Cycle ◽  
Average Density ◽  
Spatial And Temporal Variability ◽  
Source Population ◽  
Lunar Phase ◽  
Wet Season ◽  
Conservation Actions ◽  
Spatio Temporal ◽  
Substantial Decline

Birgus latro, the largest terrestrial arthropod in the world, has undergone a substantial decline globally over the last decades, with only a few healthy populations remaining where they are actively protected. We aimed to quantify demographic and spatio-temporal dynamics of a protected population of B. latro on Aldabra Atoll (Seychelles). Based on results along 2 transects on the atoll from 2007 to 2016, we calculated an average (±SE) density of 23.7 ± 1.1 ind. ha-1. This suggests a population of around 5000 B. latro in the coastal area of Picard Island, which is likely to be an underestimate due to the cryptic nature of the species. The average density within the study area was stable over the study period, and over the yearly cycle, the population exhibited high spatial and temporal variability in count, size and sex ratio and in association with the lunar cycle. Aldabra’s B. latro population is male-biased (3:1 male:female) and sexually dimorphic, with males being larger than females. Males and females moult at different times of the year, and the breeding season overlaps with the region’s wet season (December-March) and was in synchrony with the lunar phase. B. latro on Aldabra present colour polymorphism in a 4:1:1 ratio of orange:blue:intermediate (mixture of orange and blue). Results confirm that Aldabra is an important refuge for B. latro and potentially a natural source population for other areas in the region. Similar long-term studies on B. latro are encouraged to improve knowledge on the species and to support conservation actions to halt the species’ decline.

scholarly journals Spatio-temporal variations in abundance and assemblage patterns of fish larvae and their relationships to environmental variables in Sirindhron Reservoir of the Lower Mekong Basin, Thailand

2016 ◽  
Vol 63 (3) ◽  
Author(s):  
Tuantong Jutagate ◽  
Achara Rattanachai ◽  
Suriya Udduang ◽  
Sithan Lek-Ang ◽  
Sovan Lek
Keyword(s):  
Species Richness ◽  
Temporal Dynamics ◽  
Larval Fish ◽  
Fish Larvae ◽  
Abundant Species ◽  
Temporal Variations ◽  
Larval Abundance ◽  
Wet Season ◽  
North East ◽  
Spatio Temporal

The spatio-temporal dynamics of fish larvae in Sirindhron Reservoir, north-east Thailand, were investigated from February 2008 to January 2009. The five most abundant species accounted for 53.6% of the total catch and comprised Clupeicthys aesarnensis, Rasbora borapetensis, Barbonymus gonionotus, Esomus metallicus and Oreochromis niloticus. Total larval abundance and species richness varied among sampling months but did not vary with zones in the reservoir. The abundance and species richness of fish larvae showed correlation with flooding, vegetation cover, water level, water temperature and turbidity. A self-organising map (SOM) was used to represent the larval fish assemblage patterns and three assemblage patterns were clearly distinguished primarily according to seasons. In conclusion, the fish larval abundance was greatest during the wet season and the most diverse assemblages were found in the zones adjacent to the connected river upstream during the wet season.

Sign in / Sign up

Export Citation Format

Share Document