Abundance, Zonation and Foraging Ecology of Birds in Mangroves of Darwin Harbour, Northern Territory.

1996 ◽  
Vol 23 (4) ◽  
pp. 443 ◽  
Author(s):  
RA Noske

The density, seasonality, habitat utilization and foraging ecology of birds in mangals (mangrove forests) at a site on the upper reaches of Darwin Harbour were investigated by transect censusing and colour-banding over three years. Despite having only 10 species of plants, the site supported 17 confirmed and five probable breeding resident species of birds, and was visited by 30 more. From variable-width transect censuses, the mean density of birds on a 4-ha plot was estimated to be 25 ha-1, fairly consistent with densities obtained from territory mapping of colour-banded birds. Nearly 70% of the individuals belonged to just 4 species: two mangal-dependent species, the red-headed honeyeater (Myzomela erythrocephala) and the yellow white-eye (Zosterops lutea) and two more generalised species, the large-billed gerygone (Gerygone magnirostris) and the brown honeyeater (Lichmera indistincta). Only the red-headed honeyeater showed significant seasonal variation in abundance, with highest numbers during the late dry season after breeding. This coincided with the period of greatest food (nectar) availability in the mangal, due to flowering Bruguiera exaristata. Lowest numbers of the red-headed honeyeater (and the brown honeyeater) occurred in the late wet season when nectar was scarce in the mangal but abundant in Melaleuca cajuputi fringing the mangal. Several resident species held permanent territories, while others apparently shifted landward during the wet season, possibly due to the wetter conditions created by freshwater runoff and high spring tides Many species showed strong associations with particular mangal zones. Large-billed gerygones, grey whistlers (Pachycephala simplex), shining flycatchers (Myiagra alecto) and mangrove fantails (Rhipidura phasiana) were associated with the Rhizophora zone at the wetter (more frequently inundated) end of the plot; mangrove robins (Eopsaltria pulverulenta) and mangrove gerygones (Gerygone laevigaster), were encountered most in the Ceriops zone; and green-backed gerygones (Gerygone chloronata) strongly favoured the dry landward edge. Four foraging guilds were evident among 13 of the most abundant species, the largest of which was the insectivorous foliage-foraging guild. Species in this group partitioned resources by differential selection of mangrove species, heights and foraging techniques. The tiny (6.4 g) mangrove gerygone was the most specialized species, spending 80% of its time on Avicennia marina. Contrary to the literature, breeding of mangal-dwelling birds peaked during the dry season. The ecology, evolution and biogeography of mangrove-endemic birds is reviewed in the light of this study and recent information from Western Australia.

2019 ◽  
Vol 7 (1) ◽  
Author(s):  
Syahrul Muharamsyah ◽  
M Sofwan Anwari ◽  
Hafiz Ardian

Mangrove forests are unique ecosystems that have ecological, biological and socio-economic functions. The function of mangrove forests on the environment is very important especially in the coastal and oceanic regions. Mangrove forests providers of wood, leaves as raw material for medicines, and natural dye. This study aims to inventory the diversity of species of mangrove vegetation in Mendalok Village, Sungai Kunyit Subdistrict, Mempawah Regency. The benefits of this study are to provide the data on mangrove forest vegetation as basic data for local government and related agencies in efforts to protect and preserve mangrove forests in Mendalok Village, Sungai Kunyit Subdistrict, Mempawah Regency. Inventory the tree in mangrove forest used a line with measured 200 meters. There are 6 lines and the distance between the lines as far as 100 meters. The lines of observation are placed by purposive sampling. The results of research found 11 types of species and consisted of 6 genera. The genera are Avicennia, Bruguiera, Ceriops, Rhizophora, Soneratia and Xylocarpus. The species found were Avicennia alba, Avicennia marina, Bruguiera cylindrica, Bruguiera gymnorrhiza, Bruguiera parviflora, Ceriops decandra, Rhizophora apiculata, Rhizophora mucronata, Rhizophora stylosa, Sonneratia caseolaris, Xylocarpus mollucensis. Diversity of mangrove species in Mendalok Village, Sungai Kunyit Subdistrict, Mempawah Regency was high and should be maintained for conservation and ecotourism area. Keywords : conservation, ecotourism, mangrove, Mendalok Village


2020 ◽  
Vol 8 (7) ◽  
pp. 528
Author(s):  
Fareha Hilaluddin ◽  
Fatimah Md. Yusoff ◽  
Tatsuki Toda

A study on seasonal phytoplankton abundance and composition in a mangrove estuary, Matang Mangrove Forest Reserve (MMFR), Malaysia, was carried out to determine the phytoplankton structure in this ecosystem, and to identify potential indicators of environmental changes. Phytoplankton samples were collected bimonthly from June 2010 to April 2011, to cover both dry (June to October) and wet (November to April) seasons, at four selected sampling sites along the river. Diatoms showed the highest number of species (50 species) from a total of 85 phytoplankton species from 76 genera. Diatoms contributed more than 90% of the total phytoplankton abundance during the dry season (southwest monsoon) and less than 70% during the wet season (northeast monsoon) as dinoflagellates became more abundant during the rainy season. Two diatoms were recorded as dominant species throughout the sampling period; Cyclotella sp. and Skeletonema costatum. Cyclotella sp. formed the most abundant species (62% of total phytoplankton) during the dry period characterized by low nutrients and relatively low turbidity. Skeletonema costatum contributed 93% of the total phytoplankton in October, which marked the end of the dry season and the beginning of the wet season, characterized by strong winds and high waves leading to the upwelling of the water column. Massive blooms of Skeletonema costatum occurred during the upwelling when total nitrogen (TN) and total phosphorus (TP) concentrations were highest (p < 0.05) throughout the year. The abundance of diatom species during the wet season was more evenly distributed, with most diatom species contributing less than 12% of the total phytoplankton. Autotrophic producers such as diatoms were limited by high turbidity during the northeast monsoon when the rainfall was high. During the wet season, Cyclotella and Skeletonema costatum only contributed 9% and 5% of the total phytoplankton, respectively, as dinoflagellates had more competitive advantage in turbid waters. This study illustrates that some diatom species such as Cyclotella sp. and Skeletonema costatum could be used as indicators of the environmental changes in marine waters.


Crustaceana ◽  
2013 ◽  
Vol 86 (9) ◽  
pp. 1051-1069 ◽  
Author(s):  
Beatriz López ◽  
Jesús E. Conde

In order to investigate if the variety of resources consumed by Aratus pisonii (H. Milne Edwards, 1837) changes along a structural mangrove gradient, the natural diet of this crab species was studied in five mangrove forests. Mangrove forests with different degrees of structural development (arboreal, arbustive, scrub) and located in different environments (estuarine, marine, hypersaline) on the northwest coast of Venezuela were considered, during the rainy and dry seasons. Rhizophora mangle Linnaeus, 1753 was the predominant mangrove species. The gut contents of 313 individuals were analysed, yielding a total of 12 prey categories. The diet of A. pisonii was based on mangrove fragments (leaves and bark). The index of relative importance (IRI) of mangrove fragments varied between 58% and 96%. Other items supplemented the diet: seagrass, algae, insects and crustaceans. The variety of resources consumed by A. pisonii was related to the mangrove structure and varied with the season. During the rainy period food diversity in the gut content increased, as mangrove heterogeneity and complexity increased, but during the dry season the trend was reversed. Aratus pisonii appears to enhance an opportunistic feeding behaviour when leaf quality decreases, which occurs during the dry season mainly in the hypersaline mangroves with less structural development (arbustive and scrub). During the drought the IRI of the items of animal origin increased in all the localities; this could be a response to the nutritional needs of the crabs during this season. In this work, we report the first documented egg consumption of its conspecifics, which supports the idea of cannibalistic behaviour associated mainly with crabs that live in the hypersaline and scrub mangrove with the lowest structural development and leaf quality.


2008 ◽  
Vol 98 (1) ◽  
pp. 17-23 ◽  
Author(s):  
Carlos S. Filho ◽  
Claudia H. Tagliaro ◽  
Colin R. Beasley

Shipworms are important decomposers of wood, especially in mangrove forests where productivity is high. However, little emphasis has been given to the activity of shipworms in relation to the export of nutrients from mangroves to adjacent coastal areas. As a first step to obtaining such information, the frequency of colonized mangrove driftwood as well as shipworm density and length were studied by collecting washed up logs during a year at Ajuruteua beach, state of Pará, northern Brazil. A single species, Neoteredo reynei (Bartsch, 1920), was found colonizing driftwood. Although large colonized logs were most common on the beach, shipworm density was higher in small logs, especially during the dry season. In general, however, density was higher during the wet season (January to April) and lowest in July. Overall shipworm mean length was 9.66cm. In large logs, mean length increased between the wet and dry seasons. However, there was no difference in length among log size categories. Mean shipworm length was similar throughout most of the year but tended to be greater in July. Although salinity varied between 10.9 and 40 during the year, no relationship was found between salinity and density or length. The results suggest that shipworm activity in driftwood logs is relatively constant throughout the year. Increased air humidity and rainfall may promote survival during the wet season. Large logs may take longer to colonize and thus have lower densities than small ones which are scarce probably because they are destroyed rapidly by shipworm activity. However, data on the disintegration of logs would be necessary to test this hypothesis. Larger size of shipworms in the dry season may be related to growth after an earlier recruitment period. Shipworms in large logs during the dry season may be better protected from dessication and high temperatures by the insulating properties of the larger volume of wood.


2021 ◽  
Vol 22 (9) ◽  
Author(s):  
Agung Suwanto ◽  
Noverita Dian Takarina ◽  
Raldi Hendro Koestoer ◽  
Evi Frimawaty

Abstract. Suwanto A, Takarina ND, Koestoer RH, Frimawaty E. 2021. Diversity, biomass, covers, and NDVI of restored mangrove forests in Karawang and Subang Coasts, West Java, Indonesia. Biodiversitas 22: 4115-4122. Indonesia has been recognized as the country with greatest diversity of mangrove species with significant amount of carbon sink and biomass. In few recent decades, mangrove forests have been deforested significantly. One of the solutions to deal with mangrove deforestation is through restoration. West Java north coasts are one of the areas that have experienced deforestation, however and mangrove restorations have been conducted mainly in Karawang and Subang coasts. Correspondingly this research aims to assess the mangrove diversity using index and biomass resulted from restoration program in those coasts. To assess the mangrove diversity in each coast on June 2021, 6 sampling stations containing 3 replicated sample plots of size 10 m × 10 m were located. In total 8 species with 1549 trees were been sampled. In Subang the order of mangrove species from common to less-common species were Avicennia marina > Rhizophora mucronata > Sonneratia caseolaris > Acanthus ilicifolius > Bruguiera gymnorhiza. While the order in Karawang was Avicennia marina > Rhizophora mucronata > Rhizophora apiculata > Sonneratia caseolaris > Bruguiera gymnorhiza. The mangrove diversity (H)’ was significantly different (p = 0.000, F = 2.216) with diversity in Subang Coast (average H' = 1.326, 95% CI: 1.15-1.5) was higher than in Karawang (average H’ = 1.063, 95%CI: 0.934-1.2). Estimated restored mangrove covers in Subang were 3.612 km2 and 0.46 km2 in Karawang. R. mucronata was mangrove species that has the highest biomass with the value of 1337.91 mg ha-1 and the lowest was A. marina with value of 14.3 mg ha-1. The results suggest that restoration areas in Subang and Karawang have significant contributions to maintain mangrove diversity, biomass, and covers.


2020 ◽  
Vol 153 (3) ◽  
pp. 390-398
Author(s):  
Italo F. Treviño-Zevallos ◽  
Carlos Lado

Background – The humid montane forests on the eastern slopes of the Peruvian Andes are known for their high biodiversity and natural resources. While their incredibly rich plant and animal communities are still in the process of being discovered, the diversity of smaller organisms such as the Myxomycetes are even more scarcely known. In this work, we document the Myxomycete diversity in these montane forests and evaluate species abundance, occurrence by substrates, distribution, and seasonality, thus documenting population status and species ecology.Material and methods – The study was carried out at the Wayqecha Biological Station located in the Cusco region of Peru. Two sampling campaigns took place in late January (wet season) and early May (dry season) of 2018. We performed a species inventory and evaluated alpha diversity, assemblage similarity, and abundance of Myxomycetes within six 100 m2 plots. We documented variations of species richness and abundance between seasons as well as between substrates. Results – We recorded a total of 81 taxa of Myxomycetes. The order Physarales was the most diverse, and the most abundant species were Didymium squamulosum and Diderma deplanatum during the wet and dry season, respectively. The substrate with highest diversity overall was dead leaves. Diversity was similar in both seasons but with a notable species turnover. Conclusion – The humid montane forest on the eastern slopes of the Andes in Peru revealed an unexpected richness in Myxomycetes. Based on our results, we conclude that this type of forest harbours one of the greatest Myxomycetes diversities in the Peruvian territory, also due to the important seasonal species turnover.


2020 ◽  
Vol 2 ◽  
pp. ec02037
Author(s):  
Shirlene C. B. Silva ◽  
José J. Corrêa-Neto

Among the varieties of insects present in mangroves, termites can easily colonize mangrove forests by their winged forms, and thus, build arboreal nests. In view of the presence of this order in mangroves, this work presents the results of a sampling of Termites (Blattaria, Isoptera) in mangrove forests on the Amazon coast, as well as highlighting ecological aspects of these insects. Two collections were carried out during an annual cycle (dry and rainy) at six sampling sites located in the mangroves of Soure on Marajó Island, Pará. In each sampling site, a 100 mx 3 m transection was delimited, subdivided into 10 plots of land. 5 mx 3 m, with an interval of 5 m between each plot, with a sampling effort of 1h / person in each plot in search of termites in the different microhabitats present in the mangrove. A total of seven species distributed in three genera and three families were found over an annual cycle. The most abundant species were Nasutitermes corniger (Motschulsky, 1855) (38.70%), Nasutitermes nigriceps (Haldeman, 1853) (25.00%) and Nasutitermes surinamensis (Holmgren, 1910) (20.16%). The xylophagous termites were dominant and the dry season the number of species and specimens was higher.


2006 ◽  
Vol 22 (4) ◽  
pp. 385-395 ◽  
Author(s):  
Julie A. Jedlicka ◽  
Russell Greenberg ◽  
Ivette Perfecto ◽  
Stacy M. Philpott ◽  
Thomas V. Dietsch

This study examined the foraging behaviour of a resident bird species, the rufous-capped warbler (RCWA, Basileuterus rufifrons), in a shaded-coffee farm in Chiapas, Mexico. Unlike many resident species that use shaded-coffee agroecosystems seasonally, RCWAs do not move to other habitats when migrants are present. RCWA foraging was compared when migrant birds were present (dry season) and absent (wet season). It was hypothesized that RCWAs would exhibit a seasonal foraging niche shift because of resource competition with migrants. Observations from both the canopy and coffee understorey show that RCWAs foraged almost equally in both vegetative layers during the wet season although they were more successful foraging in the canopy. In the dry season, migrants foraged primarily in the canopy and RCWAs shifted so that 80% of RCWA foraging manoeuvres were in the understorey. At that time RCWAs foraged less successfully in both vegetative layers. Avian predation in the dry season was found to reduce densities of arthropods by 47–79% in the canopy, as opposed to 4–5% in the understorey. In the canopy, availability of large (>5 mm in length) arthropods decreased by 58% from the wet to dry season. Such resource reductions could have caused the RCWA foraging niche shift yet other alternative or additional hypotheses are discussed. Shifts in foraging niche may be a widespread mechanism for some small insectivorous residents to avoid seasonal competition with abundant migrant species.


2005 ◽  
Vol 53 (2) ◽  
pp. 109 ◽  
Author(s):  
Grey T. Coupland ◽  
Eric I. Paling ◽  
Keith A. McGuinness

Mangrove communities in the tropical north of Australia are some of the most species rich in the world, yet surprisingly little is known of their reproductive and vegetative phenology. This study investigated the phenology of four mangrove species: Avicennia marina (Forsk.) Vierh., Ceriops australis (C.T.White) Ballment, T.J.Sm & Stoddart, Rhizophora stylosa Griff. and Sonneratia alba J.Smith, in Darwin Harbour over 24 months. Investigations included documenting the flowering and fruiting phenology, periods of leaf flush and leaf longevity. Flowering in these mangroves generally occurred during the dry season (June–October), with the exception of R. stylosa in which flowering occurred in the middle of the wet (December–February). Fruits and propagules were released in the dry and ‘build up’ periods (August–November), with the exception of A. marina, which released propagules in the middle of the wet season. Fruit and/or propagule maturation took less than 2 months in A. marina and S. alba, whereas in C. australis and R. stylosa maturation took 12 and 11 months, respectively. Timing of new leaf production generally coincided with the wet season, after the flowering and fruiting periods of each of the four species. Periods of leaf flush and leaf fall were often closely linked, and species with longer-lived leaves produced fewer leaves at each period of leaf flush. Maximum leaf longevity varied considerably among mangroves, ranging from 8 months in the lower canopy of S. alba to more than 24 months in C. australis. There was also large variability in leaf longevity among different regions of the canopy, with shade leaves generally living longer than sun leaves, and leaves in the upper canopy (3–7 m) longer than those in the lower regions (0–3 m).


2019 ◽  
pp. 67-75
Author(s):  
Teofanes Patindol ◽  
Eulito Casas

This study reflects the present status of Tacloban City mangrove vegetation and would be useful for mangrove restoration program. Surveys of mangrove forests in Tacloban City were conducted from October to November 2017 in 12 selected sites. Quadrat method was used to assess the species composition and stand structure of the canopy layer, representing seaward, middle and landward zones. The mangrove forests in Tacloban City contain 23 mangrove species belonging to 12 families and 15 genera. Rhizophoraceae and Acanthaceae are the most dominating families. As per IUCN report, among the 23 species, 4 were recognized as threatened. These include the Endangered Camptostemon philippinensis, the Vulnerable Avicennia rumpiana and the Near Threatened Aegiceras floridum and Ceriops decandra. Rhizophora Apiculata is the most abundant species, followed by Sonneratia alba. Other abundant species are Avicennia officinalis, Avicennia marina and Rhizophora mucronata. The least abundant are Bruguiera gymnorrhiza, Camptostemon philippinensis and Xylocarpus granatum. The canopy layer is composed of small-sized trees with an average tree density of 1,678 per ha and stem density of 3,133 per ha. The average height and diameter are 6.15m and 8.95cm, respectively. Mangrove diversity is generally low. Shannon index of diversity value ranges from 0.762 to 1.132, with an average value of 0.914. Understory is characterized by few species of regenerants, low density and low species diversity.


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