Diet and ontogenetic shift in habitat use byRhinosardinia bahiensisin a tropical semi-arid estuary, north-eastern Brazil

Author(s):  
Fernando José König Clark ◽  
André Luiz Machado Pessanha

The feeding biology of bahia sprat (Rhinosardinia bahiensis) was studied in two habitats of a tropical semi-arid estuary, on the north-eastern Brazilian coast. Samplings were collected on a monthly basis (January 2010–February 2011), and fish were caught during the day using an 8 m beach seine. Habitat use was size-dependent, with tidal mudflat occupied by higher size-classes than tidal creeks, which were occupied by smaller conspecifics. The diet analysis of different size-classes revealed that all sizes of fish consumed similar taxa (Calanoida, Cyclopoida and Decapoda larvae), and that the relative proportion of taxa consumed reflected fish size. Dietary differences between the two nursery areas mainly reflected prey availability. Although high diet overlap was only found between some size-classes in tidal mudflat, these results seem to demonstrate a strategy for efficient use of space potential; intraspecific competition was probably minimized by a differential habitat use patterns.

Soil Research ◽  
2014 ◽  
Vol 52 (2) ◽  
pp. 140 ◽  
Author(s):  
A. G. B. M. Albuquerque ◽  
T. O. Ferreira ◽  
G. N. Nóbrega ◽  
R. E. Romero ◽  
V. S. Souza Júnior ◽  
...  

Wetland soils, especially those under a semi-arid climate, are among the least studied soils in the tropics. The hypersaline tidal flats on the north-eastern Brazilian coast, locally named apicum, are coastal wetland ecosystems in the peripheral portions of semi-arid estuaries. Despite their great ecological importance, they have been highly impacted by anthropogenic activities. Morphological and analytical data of six soil profiles, representative of the different coastal compartments (mangroves, apicum and coastal tablelands) of the north-eastern Brazilian coast, were examined to better understand the pedogenesis of apicum soils. The hypersaline tidal flat soils were classified as Typic Fluvaquents and Typic Sulfaquents with the following main characteristics: predominance of sand fraction (62–77%); presence of high-activity clays (>24 cmolc kg–1 clay); clay fraction comprising kaolinite, illite, smectite and an interstratified smectite/illite; exchangeable complex dominated by Na+ (ESP ≥15%); elevated levels of salinity (electrical conductivity, EC 25–44 dS m–1); alkaline pH values (7.5–9.5). The sandy texture and quartz-dominated composition of the hypersaline, tidal flat soils indicate a pedogenesis associated with the superficial addition of mineral material. This upbuilding process would have lowered the watertable (relatively to the ground level) and decreased the flooding frequency by the tides, favouring salinisation and solonisation processes at the hypersaline tidal flats. Furthermore, the still-existing hydromorphism would have promoted the maintenance of gleisation and sulfidisation. The presence of pyrite on the hyper-saline tidal flat soils further corroborates the formation of apicum soils from/over buried mangroves.


Author(s):  
Humberto F. M. Fortunato ◽  
Thierry Pérez ◽  
Gisele Lôbo-Hajdu

AbstractThe Order Suberitida is defined as a group of marine sponges without an obvious cortex, a skeleton devoid of microscleres, and with a deletion of a small loop of 15 base pairs in the secondary structure of the 28S rDNA as a molecular synapomorphy. Suberitida comprises three families and 26 genera distributed worldwide, but mostly in temperate and polar waters. Twenty species were reported along the entire Brazilian coast, and although the north-eastern coast of Brazil seems to harbour a rich sponge fauna, our current knowledge is concentrated along the south-eastern Atlantic coast. A survey was implemented along the northern coast of Brazil, and the collection allowed the identification of six species belonging to the Order Suberitida. Two of them are considered new to science: Suberites purpura sp. nov., Hymeniacidon upaonassu sp. nov., and four, Halichondria (Halichondria) marianae Santos, Nascimento & Pinheiro, 2018, Halichondria (H.) melanadocia de Laubenfels, 1936, Suberites aurantiacus (Duchassaing & Michelotti, 1864), and Terpios fugax Duchassaing & Michelotti, 1864, are re-described. Taxonomic comparisons are made for Tropical Western Atlantic species and type species of the four genera. Finally, an identification key for the Western Atlantic Suberites species is provided.


Author(s):  
Okan Akyol ◽  
Halil Şen ◽  
H. Tuncay Kınacıgil

Reproductive properties of Eledone moschata from the north-eastern Aegean Sea are reported for the first time. A total of 471 specimens was collected during monthly samplings from December 2004 to November 2005. The mantle lengths of the species were between 4.5 and 15.0 cm with an average of 8.1 cm ±0.15 for 204 males, and between 2.7 and 14.0 cm with an average of 7.8 cm ±0.12 for 267 females. The annual sex ratio (males: females) of the sampled specimens was 1:1.31. Maturity stages were recorded on a monthly basis in both sexes. The highest monthly percentage of mature females (21%) and males (46%) was recorded in January 2005 and June 2005, respectively. The monthly and seasonal gonadosomatic index (GSI) results indicated that E. moschata shows two annual reproduction peaks for each sex. For males, the first spring peak occurs in March–June and the second, autumn peak is in November. For females, the first summer peak occurs in May–June and the second, winter peak is in January, respectively. On the other hand, the reproductive season extends from November to July with two peaks in the Aegean Sea. Total oocyte stock varied from 273 to 2896 with a mean of 836 ±193 oocytes. The mean size of the oocytes was 6.26 ±0.10 mm. The maximum oocyte size found was 10.7 mm. The mean length of spermatophores was of 13.66 ±0.08 mm (range: 7.3–18.3) and their average number was 52 ±6 (range: 6–172).


1999 ◽  
Vol 26 ◽  
pp. 65-73
Author(s):  
S.J.G. Hall

SummaryCharacterisations are given of the little-known Sabi sheep and the local population of the Small East African goat in two areas in NE Zimbabwe. The southern area had been more affected by drought in 1991–92. For sheep (both areas combined; n = 28 in 10 flocks) the mean declared age of breeding females and the median age at first parturition were surprisingly high (6.1 years and 4 years respectively). Breeding female goats in the southern area were younger (4.9 vs. 6.4 years), and their age at first kidding was lower (3 years vs. 5 years), than in the north (n = 122 in 25 flocks total). These advanced ages could be an after-effect of the drought. Juvenile mortality and the proportions of young that were ultimately marketed were similar to what has been found elsewhere in semi-arid Africa. Breeding females were found to be smaller than their counterparts in semi-arid areas in West Africa with mean withers heights of 56.5 cm (n = 112 goats) and 60.4 cm (n = 36 sheep). Conditions in this area appear difficult for small ruminants and the populations sampled may be well adapted to marginal environments and thus worthy of conservation.


2016 ◽  
Vol 6 (4) ◽  
pp. 91
Author(s):  
Melanie Rispel ◽  
Selma Lendelvo

Namibia is a semi-arid country and underground water sources have proven to be reliable water sources for drought-prone countries. Underground water has the ability to sustain conservation activities as long as water infrastructure is in place and maintained. Despite the different water requirements for the wildlife species, water remains an essential component of wildlife management in Namibia. Therefore, this study aims at understanding utilization of water points by various wildlife species in the Nyae Nyae conservancies, which is located in the north-eastern part of Namibia. This study used monitoring data from wildlife counts that are conducted by the Conservancy annually at water points coupled with key-informant interviews with local conservancy members and leaders as well as some stakeholders. The study shows that the Conservancy had a diverse number of wildlife species that were predominantly ungulates (70%). These species were detected at 29 water points distributed across the Conservancy. Most of the water points in the conservancy were artificial points with water drawn from the underground water sources, while a few of the water points were pans (17%). Water resources are very important resources for conservation, not only in terms of being used by wildlife but also in terms of being used to provide an indication of species diversity in the conservation.


2019 ◽  
pp. 120-130
Author(s):  
Anissa Henine-Maouche ◽  
Lyes Aissat ◽  
Riadh Moulaï

A study of the adaptation of the ant Cataglyphis bicolor in terms of feeding under insular conditions was conducted on the north-eastern coast of Algeria. For this, three pairs of stations (island-continent) were chosen. Analyzing fragments of prey species found in C. bicolor nests, the diet in each station pair was studied. The results obtained indicate that C. bicolor has an opportunistic diet characterised by insectivory. Indeed, more than 95% of the prey consumed in the six study stations were insects with a clear preference for other ants, with frequencies ranging from 52 to 87%. Among the latter, Messor barbarus, Camponotus sp., Camponotus laurenti, Pheidole pallidula and Tetramorium biskrense were the ants most predated by C. bicolor. The diversity of continental prey seemed greater than that of island environments. For the two Cap Sigli stations, the prey richness was 94 species for the continent against only 28 species for the island environment. For Boulimat, there were 27 prey species for the mainland and 20 prey species for the islet. Finally, for the Sahel region, C. bicolor was able to harvest 42 prey species on the mainland and 28 species on the island. The diversity of C. bicolor prey in the island environments seems to be a function of insect richness (prey availability) and floral richness.


2018 ◽  
Vol 40 (5) ◽  
pp. 527
Author(s):  
S. Saïdi ◽  
G. Gintzburger ◽  
L. Gazull ◽  
J. Wallace ◽  
S. Christiansen

We developed a GIS desktop model to accurately locate and map prospective areas for sustainable establishment and production of Atriplex plantations and other fodder shrubs in the desert in the north-eastern Jordanian Badiyah. The aim is to provide a tool to assist managers, local communities and development projects in Mediterranean arid and semi-arid rangelands. The model uses freely available data and GIS layers of current land use, land cover, settlement location, soil information, and derivatives from a digital elevation model to provide critical locations of drainage lines and to calculate Areas of Accumulated Water from concentrated runoff. The model identified, accurately located and mapped ~4500 ha (1.44% of the test zone) as technically appropriate for potential shrub plantations sites. The final site map must be field-checked and validated with the local communities and authorities. Our model has potential for wide application over arid and semi-arid Mediterranean rangelands from Morocco to Pakistan, with local adjustment of our parameters and rules. The model considerably reduces the risk and costs of fodder plantation establishment operations, thus increasing the feasibility of efforts to maximise fodder shrub establishment, survival and production.


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