Population ecology of the intertidal anemone Actinia tenebrosa. IV. Growth rates and longevities

1980 ◽  
Vol 31 (3) ◽  
pp. 385 ◽  
Author(s):  
JR Ottaway
Keyword(s):  
New Zealand ◽  
Population Ecology ◽  
Growth Rates ◽  
Mortality Data ◽  
Column Diameter ◽  
Growth Data ◽  
Sea Anemones ◽  
Free Living ◽  
Growth Increments ◽  
Rocky Coast

In all, 82 adults and about 600 juvenile A tenebrosa were tracked for up to 3 years These intertidal sea anemones were free-living on the rocky coast at Kaikoura, New Zealand Regular measurements of column diameters were taken for 2 years Annual growth increments were small for all sizes of A. tenebrosa observed most increments were in the range -2 to 4 mm of column diameter per year, with the smallest anemones havmg the fastest relative mean growth rates From the growth data, A tenebrosa reaches a column diameter of 40 mm in 8-66 years after settlement From mortality data, the observed adults have a predicted mean longevity of at least 50 years and a predicted maximum longevity of at least 210 years.

Population Ecology of the Itertidal Anemone Actinia tenebrosa. III. Dynamics and Environmental Factors

1979 ◽  
Vol 30 (1) ◽  
pp. 41 ◽  
Author(s):  
JR Ottaway
Keyword(s):  
New Zealand ◽  
Mortality Rate ◽  
Environmental Factors ◽  
High Temperatures ◽  
Population Ecology ◽  
Benthic Invertebrates ◽  
Rocky Intertidal ◽  
Column Diameter ◽  
Juvenile Mortality ◽  
Impact Injuries

An isolated subpopulation of A. tenebrosa was studied, for three years, on the rocky intertidal coast at Kaikoura, New Zealand. The number of adults remained very stable: 94% of adults first seen in November 1973 survived until the observations were concluded. Adults died mainly from impact injuries caused by moving rocks and logs during gales. The number of juveniles in the colony fluctuated markedly from season to season, between 81 and 225 % of the number first seen. Most settlement was in the summer months, but some occurred throughout the year. The main causes of juvenile mortality were, in order of decreasing importance, failure to successfully attach leading to probable predation by benthic invertebrates, desiccation at low tides, dislodgement or crushing by grazing molluscs, impact injuries during gales, and exposure to combinations of excessive desiccation and high temperatures at low tides. Adult mortalities appeared to be independent of size. The rate of mortality of juveniles in their first 20 days after release from brooding adults is largely independent of juvenile size. After that, the mortality rate is negatively correlated with size until juveniles exceed about 15 mm column diameter: the smaller juveniles are more susceptible to both desiccation at low tide and to fatal interference from grazing molluscs.

Does Economic Growth Pay Political Dividends in India?

2019 ◽  
Vol 67 (1-2) ◽  
pp. 166-169
Author(s):  
Vasant V. Bang ◽  
Alok Kumar Mishra
Keyword(s):  
Economic Growth ◽  
Growth Rates ◽  
Regression Equations ◽  
Economic Policies ◽  
Growth Data ◽  
Parliamentary Elections ◽  
Independent Variables ◽  
Economic Development And Growth ◽  
Bharatiya Janata Party ◽  
Ruling Party

Since independence in 1947, India has witnessed several changes in economic policies of governments. Economic reforms were started in India in 1984 and were accelerated later in 1991. It is believed that Bharatiya Janata Party won the 2014 parliamentary elections on the promise of economic development and growth. In this article, an attempt has been made to investigate the link between economic and electoral performances in Indian elections. The data for 1951–2014 period has been analysed by establishing regression equations using vote percentage received by a ruling party as dependent variable and sectoral economic growth during the ruling tenure as independent variables. Comparisons have been made between the pre- and post-1984 eras. An important contribution of this article is that it highlights the fact that electoral performances can be better explained using sectoral growth data as compared to overall GDP growth rates. The article also highlights a significant role played by volatility in growth rates.

Dynamic Predictive Model for Growth of Bacillus cereus from Spores in Cooked Beans

2017 ◽  
Vol 81 (2) ◽  
pp. 308-315 ◽  
Author(s):  
Vijay K. Juneja ◽  
Abhinav Mishra ◽  
Abani K. Pradhan
Keyword(s):  
Bacillus Cereus ◽  
Growth Rates ◽  
Linear Models ◽  
Growth Models ◽  
Maximum Growth ◽  
Effect Of Temperature ◽  
Coefficient Of Determination ◽  
Growth Data ◽  
Three Phase ◽  
Primary Model

ABSTRACT Kinetic growth data for Bacillus cereus grown from spores were collected in cooked beans under several isothermal conditions (10 to 49°C). Samples were inoculated with approximately 2 log CFU/g heat-shocked (80°C for 10 min) spores and stored at isothermal temperatures. B. cereus populations were determined at appropriate intervals by plating on mannitol–egg yolk–polymyxin agar and incubating at 30°C for 24 h. Data were fitted into Baranyi, Huang, modified Gompertz, and three-phase linear primary growth models. All four models were fitted to the experimental growth data collected at 13 to 46°C. Performances of these models were evaluated based on accuracy and bias factors, the coefficient of determination (R2), and the root mean square error. Based on these criteria, the Baranyi model best described the growth data, followed by the Huang, modified Gompertz, and three-phase linear models. The maximum growth rates of each primary model were fitted as a function of temperature using the modified Ratkowsky model. The high R2 values (0.95 to 0.98) indicate that the modified Ratkowsky model can be used to describe the effect of temperature on the growth rates for all four primary models. The acceptable prediction zone (APZ) approach also was used for validation of the model with observed data collected during single and two-step dynamic cooling temperature protocols. When the predictions using the Baranyi model were compared with the observed data using the APZ analysis, all 24 observations for the exponential single rate cooling were within the APZ, which was set between −0.5 and 1 log CFU/g; 26 of 28 predictions for the two-step cooling profiles also were within the APZ limits. The developed dynamic model can be used to predict potential B. cereus growth from spores in beans under various temperature conditions or during extended chilling of cooked beans.

scholarly journals STOCHASTIC DIFFERENTIAL EQUATION: AN APPLICATION TO MORTALITY DATA

2020 ◽  
Vol 8 (6) ◽  
Author(s):  
Rajani P. Agadi ◽  
A. S. Talawar
Keyword(s):  
Differential Equation ◽  
New Zealand ◽  
Stochastic Differential Equation ◽  
Mortality Rates ◽  
Mortality Data

In the present paper we consider an application of stochastic differential equation to model age-specific mortalities. We use New Zealand mortality data for the period 1948–2015 to fit the model. The point predictions of mortality rates at ages 40, 60 and 80 are quite good, almost undistinguishable from the true mortality rates observed.  

scholarly journals Functional Ecology of Iceplant Taxa and Their Role in Eco-restoration of New Zealand Sand Dunes

2021 ◽  
Author(s):  
◽  
Guyo Duba Gufu
Keyword(s):  
New Zealand ◽  
Plant Species ◽  
Plant Communities ◽  
Growth Rates ◽  
Sand Dunes ◽  
Intergeneric Hybrid ◽  
Leaf Production ◽  
Natural Plant ◽  
Carpobrotus Edulis

<p>Biological invasion by non-native plant species has often been cited as a cause of native biodiversity loss. While the outcome of species invasions depends on interactions between exotic and resident native species, most studies of biological invasions have focused solely on the direct negative impacts of non-indigenous species on native biota. Although investigations of the role of competition in shaping natural plant communities were dominant in the previous generations and are still popular, more recent experimental research has uncovered the striking influence of facilitation on community dynamics. This thesis aims to investigate competitive and facilitative influence of the invasive South African iceplant (Carpobrotus edulis) on Spinifex sericeus, a native foredune grass species, with particular reference to implications of these interactions for dune restoration in New Zealand. It further explores the growth rates, substrate preferences and mating systems of the exotic and native iceplant taxa found in New Zealand. I begin by briefly outlining the influence of competition and facilitation on natural plant communities with reference to the role of facilitation in eco-restoration. I also give a few examples where exotic species have been found to facilitate native ones. Secondly, a neighbour removal experiment was conducted on coastal sand dunes with the main aim of studying the effects of Carpobrotus edulis on establishment of Spinifex sericeus at the foredune region. Finally, I compared the growth rates of the most widely distributed iceplant taxa in New Zealand in different substrates and the breeding systems of the exotic Carpobrotus.  Examples abound in literature of exotic plant species facilitating native ones especially in forestry. In the neighbour removal study, Carpobrotus edulis protected Spinifex seedlings against storm erosion, sandblasting and salt sprays while at the same time suppressing its leaf production. Suppression of Spinifex leaf production was more pronounced at top of the dune where stress elements is presumably more benign. There was no evidence of allelopathic suppression of Spinifex by C. edulis. Only Carpobrotus chilensis displayed some level of substrate preference by putting on relatively lower biomass in gravel. The exotic Carpobrotus spp. put on greater dry matter content than the native Disphyma australe and the Carpobrotus-x-Disphyma hybrid. The hybrid displayed a faster vegetative growth rate whereas D. australe allocated relatively more biomass to the roots than the shoot. Both Carpobrotus spp. are self compatible and highly capable of intrageneric and intergeneric hybridisation. Mass removal of the existing exotic iceplant stands from foredunes along high energy coasts is not advisable as they serve as useful stabilisers. The intergeneric hybrid is sexually sterile with sparsely spread stolons that could allow co-occurrence with other species and therefore is more suitable for foredune stabilisation. However, more research needs to be conducted on the ecology of the intergeneric hybrid.</p>

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.

Microhabitat characteristics and reproductive status of male Euchordodes nigromaculatus (Nematomorpha)

1999 ◽  
Vol 73 (1) ◽  
pp. 91-93 ◽  
Author(s):  
F. Thomas ◽  
A. Schmidt-Rhaesa ◽  
R. Poulin
Keyword(s):  
New Zealand ◽  
Current Velocity ◽  
Physical Characteristics ◽  
Reproductive Status ◽  
Mountain Stream ◽  
High Current ◽  
Free Living ◽  
High Current Velocity

In a sample of 61 free-living, postparasitic male Euchordodes nigromaculatus collected from a mountain stream in New Zealand, we found that only large males are found in areas of high current velocity. Thirty-five of the 61 males still contained gametes; these worms were found in wider, deeper, and slower-flowing parts of the stream relative to worms that had released their gametes. These results suggest that the physical characteristics of the immediate microhabitat of male worms can determine their probability of mating.

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