Reproductive biology of the parsley frog, Pelodytes punctatus, at the northernmost part of its range

1993 ◽  
Vol 14 (2) ◽  
pp. 131-147 ◽  
Author(s):  
M. Ohm ◽  
A.G. Toxopeus ◽  
J.W. Arntzen
Keyword(s):  
Reproductive Biology ◽  
Breeding Season ◽  
Adult Population ◽  
First Year ◽  
Adult Size ◽  
Dune System ◽  
Population Size Estimates ◽  
Coastal Dune System ◽  
Source Sink ◽  
Second Period

AbstractThe reproductive biology and population dynamics of Pelodytes punctatus were studied at the breeding season over a three year period in a coastal dune system located at the extreme northwestern border of the species' range. Adult population size estimates ranged from about 100 in the first year to 60 in the third year. Males were remarkably sedentary near the pond under artificially provided shelters. Many were observed during the most of the breeding season which lasted from mid-March or the end of March to the end of April or mid-May. Most spawning took place in the second half of March or early April. In two years out of three a second period of spawning involving fewer animals was observed in the first half of May. Both periods of spawning coincided with, or shortly followed, periods of rising median air temperature. Egg-clutches were deposited in the deepest parts of pond, mainly on submerged vegetation not reaching the surface. An average sized clutch contained approximately 360 eggs. Development of the embryos until hatching took from 4 to 14 days, depending on the ambient temperature. Larval development and growth were fast. Recently metamorphosed froglets at a size of around 18 mm were found from the end of May onwards. Juveniles may reach adult size in the autumn of the year that they were born. Adult frogs did not show a strong fidelity to the breeding pond between years. In the study area the population structure of Pelodytes punctatus seems to be best described by a source - sink model in which flourishing populations in the dunes give rise to short lived satellite populations outside the dunes.

Breeding ecology of the fairy martin

1999 ◽  
Vol 47 (5) ◽  
pp. 463 ◽  
Author(s):  
Michael J. L. Magrath
Keyword(s):  
Breeding Season ◽  
Weather Conditions ◽  
Adult Mortality ◽  
First Year ◽  
Breeding Ecology ◽  
Adult Males ◽  
Annual Productivity ◽  
Adverse Weather ◽  
Colony Site ◽  
The One

The breeding biology of the fairy martin, Hirundo ariel, was studied over three years (1992–95) in the Yarra Valley, Victoria. Adult males and females in this population were morphologically similar, though only females acquired a brood patch during the breeding season. Colonies ranged in size from 8 to 29 nests. Birds arrived in the study area in September and usually commenced laying in October, though nesting activities were generally asynchronous both between and within colonies. Most colonies contained active nests until February. At least 16% of adults and 5% of fledglings, on average, returned to the study area in the following year. Returning adults generally nested at the same colony site as the previous year, while most first-year birds nested at sites other than their natal colony. Adult males were more likely to return than adult females. Clutch size ranged from 2 to 5, with a mean of 3.5, and declined over the season. The incubation period varied from 12 to 18 days with a mean of 13.7. A mean of 1.8 chicks fledged per completed clutch, while 60% of clutches produced at least one chick. The period from hatching to fledging varied from 17 to 32 days, with a mean of 22.1, and increased with brood size. Fledging success was highest during the middle of the breeding season. Adverse weather conditions, resulting in the abandonment of clutch and brood, were the most common cause of nest failure, and on several occasions also resulted in adult mortality. Almost half the breeding females produced at least two clutches in the one season. Pairs produced from 0 to 8 fledglings per season, with those that commenced nesting earlier in the season having higher annual productivity. These results are discussed in relation to the breeding ecology of other members of the Hirundinidae.

scholarly journals Aggregations and parental care in the Early Triassic basal cynodontsGalesaurus planicepsandThrinaxodon liorhinus

PeerJ ◽  
2017 ◽  
Vol 5 ◽  
pp. e2875 ◽  
Author(s):  
Sandra C. Jasinoski ◽  
Fernando Abdala
Keyword(s):  
Parental Care ◽  
Reproductive Biology ◽  
Fossil Record ◽  
Size Difference ◽  
Early Triassic ◽  
Adult Size ◽  
Extensive Survey ◽  
Comprehensive Survey ◽  
Extinct Group ◽  
Mixed Age

Non-mammaliaform cynodonts gave rise to mammals but the reproductive biology of this extinct group is still poorly known. Two exceptional fossils ofGalesaurus planicepsandThrinaxodon liorhinus, consisting of juveniles closely associated with an adult, were briefly described more than 50 years ago as examples of parental care in non-mammaliaform cynodonts. However, these two Early Triassic fossils have largely been excluded from recent discussions of parental care in the fossil record. Here we re-analyse these fossils in the context of an extensive survey of other aggregations found in these two basal cynodont taxa. Our analysis revealed six other unequivocal cases of aggregations inThrinaxodon, with examples of same-age aggregations among immature or adult individuals as well as mixed-age aggregations between subadult and adult individuals. In contrast, only one additional aggregation ofGalesauruswas identified. Taking this comprehensive survey into account, the two previously described cases of parental care inGalesaurusandThrinaxodonare substantiated. The juveniles are the smallest specimens known for each taxon, and the size difference between the adult and the two associated juveniles is the largest found for any of the aggregations. The juveniles ofThrinaxodonare approximately only 37% of the associated adult size; whereas inGalesaurus, the young are at least 60% of the associated adult size. In each case, the two juvenile individuals are similar in size, suggesting they were from the same clutch. Even though parental care was present in bothGalesaurusandThrinaxodon, intraspecific aggregations were much more common inThrinaxodon, suggesting it regularly lived in aggregations consisting of both similar and different aged individuals.

Population ecology of the Intertidal Anemone Actinia tenebrosa II Geographical distribution, synonymy, reproductive cycle and fecundity

1979 ◽  
Vol 27 (2) ◽  
pp. 273 ◽  
Author(s):  
JR Ottaway
Keyword(s):  
New Zealand ◽  
Geographical Distribution ◽  
Breeding Season ◽  
Reproductive Cycle ◽  
Population Ecology ◽  
Adult Population ◽  
Gonad Development ◽  
Reproductive Mode ◽  
The Other

Synonymy and geographical distribution of A. tenebrosa are discussed. Reproductive cycle and fecundity were examined between 1972 and 1975 inclusive at Kaikoura, New Zealand. At any one time, up to 77% of the adult population developed gonads and 20-94% of adults were brooding young. The main periods of gonad development, November-April inclusive, coincided with the warmest annual sea temperatures. Over 99.4% of brooded embryos dissected from 1851 adults were tentaculate young; the rest were planulae. It is suggested that the normal reproductive mode of the observed population is cross-fertilizing labile gonochorism, in which adults change from one sex to the other within each breeding season. Brooding adults would therefore be the maternal parents of their brooded embryos, even though subsequently the brooders would appear to be asexual or could become functional males.

Geomophological and vulnerability analysis of a coastal delta under increased hydrological alteration over the past two centuries: Tana River delta, Kenya, East Africa.

2021 ◽  
Author(s):  
Peter Gitau ◽  
Stéphanie Duvail ◽  
Dirk Verschuren ◽  
Dominique Guillaud
Keyword(s):  
Sea Level Rise ◽  
East Africa ◽  
Sea Level ◽  
Coastal Dune ◽  
River Delta ◽  
River Channels ◽  
Dune System ◽  
The Past ◽  
Tana River ◽  
Coastal Dune System

<p>Coastal deltas worldwide are under risk of degradation due to the increasing impacts of sea-level rise, and continuous human alterations of river basin hydrology. This research highlights the geomorphological changes that have occurred within the Tana River delta in Kenya, an important deltaic ecosystem of high biodiversity value in East Africa.</p><p>The geomorphological features (river channels, floodplain, coastal dune system) and their evolution over the past two centuries were described. Aerial and satellite imagery was used to assess the magnitude and distribution of coastal changes from the 1960s to present.  Additionally, sediment cores recovered within the mangrove environment were analysed to establish the succession of sedimentation periods and patterns. Finally, we explored the response of the coastal processes of deposition and erosion under anthropogenic alterations of the hydrological system.</p><p>It was established that over the past two centuries Tana River has changed its main channel and outlet to the Indian Ocean on three occasions. A first river avulsion occurred in the 1860s, followed by a second avulsion in the late 1890s that was promoted by human interference through channel expansion and dyke construction. The third change in river course has occurred gradually over the past 20 years, amid human efforts to engineer the river channels.</p><p>From the sediment analysis and radiocarbon dating, it is ascertained that the lower deltaic region developed rapidly over the past ~180 years, facilitated by increased sedimentation from the main Tana River. On the other hand, analysis of the coastline changes indicate that there has been increased erosion of the coastal dune system and mangrove vegetation along the former river outlet, leading to rapid marine intrusion into local subsistence farming areas. By analysing the combined impacts of both natural river dynamics and human alteration we highlight how the integrity of the Tana River delta has increasingly become vulnerable under present sea level rise and continued upstream river alteration.</p>

Mortality and breeding failure of little penguins, Eudyptula minor, in Victoria, 1995 - 96, following a widespread mortality of pilchard, Sardinops sagax

2000 ◽  
Vol 51 (4) ◽  
pp. 355 ◽  
Author(s):  
Peter Dann ◽  
F. I. Norman ◽  
J. M. Cullen ◽  
F. J. Neira ◽  
A. Chiaradia
Keyword(s):  
At Risk ◽  
Breeding Season ◽  
Breeding Success ◽  
Egg Laying ◽  
First Year ◽  
Breeding Failure ◽  
Food Species ◽  
Intestinal Parasitism ◽  
Western Victoria

In May 1995, numbers of little penguins, Eudyptula minor, coming ashore declined at Phillip Island and St Kilda concurrently with deaths of many penguins in western Victoria and a massive mortality of one of their food species (pilchard) throughout southern Australia. Among 1926 dead penguins reported were 131 banded birdsrecovered from Phillip Island (86% adults and 14% first-year birds), 26 from Rabbit Island and six from St Kilda. The number of banded penguins found dead per number of adult Phillip Island birds at risk was 2.3% in 1995 compared with an annual mean of 0.7% for 1970–93. Of 29 corpses autopsied, at least 26 died of starvation associated with mild–severe gastro-intestinal parasitism. Following the pilchard mortality, egg-laying by penguins in the subsequent breeding season (1995–96) was ~2 weeks later than the long-term mean and 0.3 chicks were fledged per pair compared with the long-term mean of 1.0. Unlike previous years, few penguins were recorded in Port Phillip Bay in September–October 1995, a period when pilchard schools were infrequently seen. It is concluded that the increase in penguin mortality in northern Bass Strait and the significant reduction in breeding success were associated with the widespread pilchard mortality.

scholarly journals Reproduction performance of beef cattle mated naturally following synchronization in the Central Bushveld bioregion of South Africa

2015 ◽  
Vol 44 (5) ◽  
pp. 70-74
Author(s):  
SM Grobler ◽  
MM Scholtz ◽  
JPC Greyling ◽  
FWC Neser
Keyword(s):  
South Africa ◽  
Beef Cattle ◽  
Breeding Season ◽  
Recovery Period ◽  
Beef Cows ◽  
First Year ◽  
Natural Mating ◽  
The Difference ◽  
Calving Season ◽  
Main Component

The estimated calving percentage of beef cattle is 62% in the commercial sector of South Africa. Fertility is regarded as the main component influencing total herd efficiency in beef cattle. If the long calving seasons can be shortened and the calving percentage increased, more and heavier calves with a more uniform age can be weaned. Cows calving earlier in the season also have an extended “recovery period” and have the opportunity to calve in a better body condition during the next season, compared to cows calving late in the season. Cows that calve early also have a better chance of conceiving in the next breeding season and are generally seen as the more fertile animals. Research has been undertaken to evaluate the effect of oestrous synchronization followed by natural mating on the calving rate and calving distribution of multiparous beef cows. In this trial Bonsmara cows were mated naturally after synchronization over a period of four years (2009 - 2012) in an extensive production system on natural sour-mixed bushveld. The synchronized cows calved earlier during the 2009 calving season and cows in anoestrus started cycling again. The average days-to-calving after the start of the breeding season was 243 days for the synchronized cows and 267 for the non-synchronized cows. The calves born from the synchronized cows were therefore, on average, 24 days older than the calves born from the non-synchronized cows. From 2010 onwards the difference declined and it seems the biggest effect was obtained during the first year of synchronization.Keywords: Beef cattle, Marikana thorn veld, natural mating, oestrous synchronization

Reproduction of the Rabbit, Oryctolagus cunniculus (L.), on Macquarie Island, Subantarctic

1978 ◽  
Vol 5 (3) ◽  
pp. 317 ◽  
Author(s):  
IJ Skira
Keyword(s):  
Breeding Season ◽  
Annual Cycle ◽  
First Year ◽  
Corpora Lutea ◽  
Macquarie Island ◽  
Pregnant Females

The reproduction of rabbits on Macquarie I. was studied from December 1973 to February 1975. The breeding season extended from late August 1974 to mid-March 1975; both sexes showed an annual cycle in development and regression of the gonads. Between mid-October and mid-November 92% of females sampled were pregnant; during this period the maximum numbers of corpora lutea and embryos were 8.55 and 6.50 per female respectively. Few resorptions occurred although the number of pregnant females that resorbed increased as the breeding season progressed. Of all rabbit kittens produced in the 1974-75 breeding season, 64% were born by mid-December 1974. Female rabbits in their first year of breeding bore the greatest number of kittens; natality decreased as females aged.

scholarly journals The measurement by serological means of the impact of the Hong Kong/68 influenza virus on a population

1972 ◽  
Vol 6 (1) ◽  
pp. 85-88 ◽  
Author(s):  
José Alberto N. Candeias ◽  
Marguerite S. Pereira
Keyword(s):  
Influenza Virus ◽  
Hong Kong ◽  
Adult Population ◽  
Haemagglutination Inhibition ◽  
Sharp Decrease ◽  
Sao Paulo ◽  
First Year ◽  
São Paulo ◽  
Serum Samples ◽  
The Impact

In order to obtain evidence on the size of the impact of the Hong Kong/68 variant of influenza A2 virus on the population of São Paulo, Brazil, serum samples taken in 1967 before this variant appeared and during successive years after it appeared were examined for their antibody content. Haemagglutination-inhibition tests performed on a total of 2726 serum samples from adults showed a sharp decrease in 1969 of the proportion of sera without antibody to the Hong Kong/68 variant and a corresponding mercase in the proportion with high titres. It was concluded that about three-quarters of the adult population became infected at some time after the variant appeared, the majority in the first year of prevalence.

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