scholarly journals Population size, age structure and life cycle of Levant water frog, Pelophylax bedriagae (Camerano, 1882) (Amphibia: Anura: Ranidae) in Lake Sülüklü (Manisa)

2017 ◽  
Vol 34 (2) ◽  
pp. 169-177 ◽  
Author(s):  
İlhan Bayryam İsmail ◽  
Kerim Çiçek
Author(s):  
Kerim Çiçek ◽  
Meltem Kumaş ◽  
Dinçer Ayaz ◽  
Ahmet Mermer ◽  
Ş. Deniz Engin

2018 ◽  
Vol 5 (1) ◽  
pp. 54-63
Author(s):  
Simeon Lukanov ◽  
Georgi Popgeorgiev ◽  
Nikolay Tzankov

AbstractWater frog mating calls from two localities were studied and analyzed. Recordings were made in the summer of 2010 at the Arkutino swamp near the town of Primorsko and at the Vurbitza River near the town of Momchilgrad. A total of 154 calls were analyzed and the results suggested the presence of both the Marsh frog (Pelophylax ridibundus) and the Levant frog (Pelophylax bedriagae) in both sites, with the former being more frequent in Vurbitza River, and the latter – in Arkutino. At Vurbitza, we also captured and measured 2 specimens, which morphological characteristics differed from P. ridibundus and matched those of P. bedriagae. These are the first localities for P. bedriagae in Bulgaria.


Author(s):  
R. Schwarz ◽  
J.A.A. Perez

Age structure and hatchling dates of the squid Illex argentinus collected by bottom-trawl fishery in southern Brazilian waters were assessed by the analysis of statolith growth increments. Catches occurred between 2001 and 2002, from 23° to 32°S at depths of 100–700 m. Squid from juvenile to post-spawning stages were collected year round, with age estimated from 98 to 320 days and mantle lengths ranging from 112 to 376 mm. Duration of life cycle events based on statolith growth zones revealed that squids can spend about 14% of their lifespan as paralarva (~30 days), 70% as juvenile (~130 days), leaving maturity and spawning condition to the terminal 10–20% (~30–60 days). The results suggest that, unlike estimates available for Patagonian populations, a general 0.5 year lifespan is predicted for I. argentinus off Brazil. The wide range of size-at-ages implied that catches of shortfin squid off southern Brazil probably include squid hatched throughout the year. Mature and spawning squid caught in summer months hatched in winter and spring, while winter catches revealed mature-spawning individuals hatched both in summer/autumn (~6 months of age) and winter/spring periods (~10–11 months of age). It has been argued that such groups may combine both squid resident of Brazilian outer shelf and slope (22°–34°S) with a six months' lifespan and migrating squid originated from the northern Patagonian shelf (~42°S) with 10–11 months' lifespan.


2017 ◽  
pp. 65-72
Author(s):  
Z. О. Palian ◽  
I. H. Bondarenko

A balanced change in demographic processes should be considered as a prerequisite and, at the same time, as a result of the stable development of the state. Reproduction intensity depends not only on the character of demographic behavior, but also on the presence of contingents of the population, providing or potentially able to provide for its replacement. The dynamics of Ukrainian population, the transformation of its gender-age structure during the period of independence, taking into account the intensive and structural factors of natural increase and migration, is considered. During 2002-2015, the regime of survival and fertility improved in Ukraine, due to which the depopulation slowed down somewhat. But even these positive changes do not compensate for the loss of population size as a result of systematic aging, reducing the proportion of reproductive contingent and its aging. Significant demographic losses, direct and indirect, were caused by a hybrid war from Russia. Alienation of the territory of the Crimea and parts of Donbas is not only a minus 2.5 million citizens of Ukraine. This is a change in the structure of the population - a decrease in the proportion of older age groups that increase the demographic load and worsen the characteristics of survival and fertility of the maternal generation. In this work are presented the results of the short-term simulation of population size and structure taking into account modern trends of replacements components and existing administrative-territorial changes. Two scenarios of the forecast for 2018 have been developed, and the base year it was taken in 2013, when the Crimea was part of Ukraine. The first, realistic scenario was based on the preservation of the current situation - Ukraine without the annexed Crimea and the occupied part of the Donbas. The second scenario imitates the return to Ukraine of all the lost territories. Simulation showed that the population of Ukraine will be reduced by both scenarios, but to 41.9 million people under the scenario without the occupied and annexed territories and to 44.7 million people in the second scenario. The finish of war will due to slow down the death rate to 14.9%0. The age structure of the population does not differ significantly in two scenarios, because the forecast horizon is very short (4 years). The share of generation of parents and women of reproductive age in both variants of the forecast decreases. However, in the case of returning Crimea, it will be even lower (47.4% vs. 47.5% in the first scenario). The reason for this is the emigration of young and middle-aged people to the mainland of Ukraine and to the Russian Federation, which provided some preferences to the settlers from Ukraine. Expected structural changes combined with the modern life and fertility regime will worsen natural population growth rates in both scenarios. In further research is planned to build trend models of births and deaths that will allow the artificially restore the interrupted time series due to administrative-territorial incomparability of data on demographic events


Author(s):  
Roberto Ambrosini ◽  
Andrea Romano ◽  
Nicola Saino

Studies of the timing (phenology) of bird migration provided some of the first evidence for the effects of climate change on organisms. Since the rate of climate change is uneven across the globe, with northern latitudes experiencing faster warming trends than tropical areas, animals moving across latitudes are subject to diverging trends of climate change at different stages of their annual life cycle, and, consequently, they can become mistimed with the local ecological conditions, with potentially negative effects on population size. This chapter reviews the modifications induced by climate change in different migration traits, like the timing of migration events, the distribution of organisms, and the direction and the speed of movements. It also considers the effects of ecological carry-over effects and migratory connectivity on the response of birds to climate change.


1975 ◽  
Vol 19 (4) ◽  
pp. 2898-2905
Author(s):  
Nelson G. Hairston ◽  
Robert A. Pastorok

1985 ◽  
Vol 63 (6) ◽  
pp. 1316-1323 ◽  
Author(s):  
R. B. Aiken ◽  
C. W. Wilkinson

There are few studies of life history and population growth of large dytiscid beetles in North America. We sampled populations of Dytiscus alaskanus in a eutrophic lake in north central Alberta weekly in the summers of 1982 and 1983. Like many other temperate zone dytiscids, D. alaskanus has a univoltine life cycle. Dytiscus alaskanus prefers the area at the limit of emergent vegetation in the lake and is most often associated with shoreline vegetation of cattail and sedge. Populations of adult D. alaskanus are at a peak in the late spring and decline throughout the summer. Mark–recapture experiments allowed determination of total population size and monitoring of movement patterns in the lake. Data are discussed with reference to the relatively short summer with which these beetles must cope.


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