Growth Rate and Long-Term Population Dynamics of Jarrah (Eucalyptus marginata Donn ex Sm.) Regeneration in Western Australian Forest

1984 ◽  
Vol 32 (4) ◽  
pp. 353 ◽  
Author(s):  
I Abbott ◽  
O Loneragan
Keyword(s):  
Growth Rate ◽  
Population Dynamics ◽  
Intraspecific Competition ◽  
Substantial Reduction ◽  
Eucalyptus Marginata ◽  
Low Intensity ◽  
Rates Of Growth ◽  
Western Australian ◽  
Survival Of Seedlings

Five of the six stages in the regeneration of jarrah (seedling, lignotuberous seedling, seedling coppice, ground coppice and sapling) were studied in detail. Survival of seedlings is variable but usually low, and growth into the ground coppice stage usually takes 15-20 years. Growth into the sapling stage is arrested until there is substantial reduction in intraspecific competition. Lignotuberous seedlings, seedling coppice and ground coppice growing in ashbeds show faster rates of growth in length of the long axis of the lignotuber and length of the tallest shoot. Logging and prescribed (low-intensity) fires are associated with development of more seedling coppice and growth of ground coppice into saplings and poles than is fire alone.

Body growth and its implications in population dynamics of Acanthodactylus erythrurus (Schinz, 1834) in the Eastern Iberian peninsula

2019 ◽  
Vol 40 (3) ◽  
pp. 305-312
Author(s):  
Robby Marcel Drechsler ◽  
Juan Salvador Monrós
Keyword(s):  
Growth Rate ◽  
Population Dynamics ◽  
Statistical Significance ◽  
Growth Curves ◽  
High Statistical Significance ◽  
General Data ◽  
One Year ◽  
Best Fit ◽  
Logarithmic Growth

Abstract We calculated growth rate for the spiny-footed lizard (Acanthodactylus erythrurus) inhabiting coastal eastern Spain from long-term mark-recapture data. Growth curves differ between sexes, with males growing faster than females and achieving larger size maximums. In this population each sex reaches maturity at about 300 days of age, approximately 34% faster than males, and 28% faster than females studied in a population further south and west in Iberia. Our logarithmic growth model has an accuracy of 96.8% and high statistical significance ( for males and for females). Although both the exponential curve of “best fit” for growth estimated for males (), and the linear curve of “best fit” estimated for females () in a population from Cádiz (Busack and Jaksic, 1982) are also significant. The overlap between growth curves and the general data cloud of the population showed that at the end of the year the proportion of individuals younger than one year was 80% and the proportion of individuals older than one year was 20%. Our data, in agreement with calculated maximum life spans for males (1.9 years) and females (2.1 years) in Cádiz, suggest a life span of approximately two years for both sexes. Females seem to reproduce only in a unique season in their lives, at this locality, as in Cádiz (Busack and Klosterman, 1987) they likely lay only one clutch, whereas females in Morocco (Bons, 1962) may produce two.

Population Dynamics of the Western Australian Soldier Crab Mictyris Occidentalis Unno, 2008 (brachyura, Mictyridae) in the Dampier Archipelago — 30 Years of Observations

Crustaceana ◽  
2011 ◽  
Vol 84 (8) ◽  
pp. 905-937 ◽  
Author(s):  
J. Unno ◽  
V. Semeniuk
Keyword(s):  
Population Dynamics ◽  
Maximum Size ◽  
First Year ◽  
Spatial And Temporal Variability ◽  
Adult Males ◽  
Population Densities ◽  
Juvenile Recruitment ◽  
Incremental Growth ◽  
Western Australian

AbstractThe previously undescribed population dynamics of the Western Australian soldier crab, Mictyris occidentalis Unno, 2008, in King Bay, north-western Australia are elucidated, with annual observations and sampling over a 30-year period from 1980 to 2010. This is the longest recorded study of a single inter-tidal brachyuran population and shows long-term persistence of soldier crab populations in stable, sheltered habitats. The life cycle of M. occidentalis follows a cryptic subsurface juvenile and immature adult (= adolescent) phase and an emergent adult phase. Population densities were generally 500 crabs/m2 for the early 1980s, late 1980s, and during the early 2000s. Maximum population densities were high in the mid 1980s (800 crabs/m2). The spatial and temporal variability in the distribution of the population was consistent over the study period. Juvenile recruitment extends for up to 7 months of a given year between May and November with the main influx of juveniles usually in June and occasional minor influxes in August or October. Juvenile recruitment is followed by incremental growth of individuals at a rate of 1 mm/month reaching sexual maturity in the first year at 6.0-6.9 mm carapace length (CL). Adult males are larger than females with a maximum size of 15.0 mm CL compared to 12.0 mm CL, respectively. Ovigerous females are low in numbers throughout most of the year but reach a peak in February. During swarming, M. occidentalis populations partition not only by size class, with surface crabs being adults only and subsurface crabs mainly adult females and juveniles, but also by sex in that swarms are male-dominated in varying ratios.

scholarly journals Distribution, population dynamics and growth rates of Thysanopoda acutifrons, Thysanoessa inermis and Nematobrachion boöpis in the Irminger Sea, North Atlantic

2012 ◽  
Vol 93 (5) ◽  
pp. 1287-1301 ◽  
Author(s):  
R.A. Saunders ◽  
J. Rasmussen ◽  
G.A. Tarling ◽  
A.S. Brierley
Keyword(s):  
Population Dynamics ◽  
Larval Development ◽  
North Atlantic ◽  
Growth Rates ◽  
Large Body ◽  
Large Body Size ◽  
Irminger Sea ◽  
Rates Of Growth ◽  
Timing Of Spawning

Euphausiids are an important component of the northern North Atlantic ecosystem and several species are found in the Irminger Sea. However, data on euphausiids in this region are few, particularly for Thysanopoda acutifrons, Thysanoessa inermis and Nematobranchion boöpis. In this paper, we present the first data since the 1930s on the seasonal distribution and population dynamics of these species from net haul data collected in the Irminger Sea during winter, spring and summer 2001–2002. Thysanoessa inermis was the most numerically abundant (0.63–26.62 ind. 1000 m−3) of the three species in the region and comprised a biomass of 3.92–41.74 mg 1000 m−3. The species was largely found in the upper regions of the water column (0–400 m) and was distributed in the more on-shelf/shelf-break regions around East Greenland and Iceland. Growth rates were around 0.03 mm d−1for T. inermis and there was some evidence that either the timing of spawning was delayed, or larval development was prolonged in the region. Thysanopoda acutifrons was predominantly distributed below 400 m in more oceanic regions and had a low abundance (1.23–1.64 ind. 1000 m−3) throughout the Irminger Sea. However, the species comprised a relatively high proportion of biomass (19.39–31.33 mg 1000 m−3) due to its large body size. Our data showed that the species had low rates of growth (0.04 mm d−1) and development throughout the year, and that the reproductive season occurred during the overwintering period (November/December) once individuals had reached two years of age. Nematobranchion boöpis mainly occurred below 400 m at low abundance (0.06–0.18 ind.1000 m−3) levels throughout the region. The species was largely found where Atlantic waters prevailed in the Irminger Current and its growth rates were variable (0.02–0.06 mm d−1). Nematobranchion boöpis was a year-round spawner and the species had fairly rapid rates of post-larval development, with the newly spawned 0-group reaching sexual maturity within the first 6 months. Data presented in this paper provide useful baselines for understanding the possible impacts of long-term, broad-scale environmental change on the ecology of euphausiid communities in the Irminger Sea.

scholarly journals An evolutionary maximum principle for density-dependent population dynamics in a fluctuating environment

2009 ◽  
Vol 364 (1523) ◽  
pp. 1511-1518 ◽  
Author(s):  
Russell Lande ◽  
Steinar Engen ◽  
Bernt-Erik Sæther
Keyword(s):  
Growth Rate ◽  
Population Dynamics ◽  
Population Growth ◽  
Density Dependence ◽  
Stationary Distribution ◽  
Population Growth Rate ◽  
Long Term Evolution ◽  
Intrinsic Rate Of Increase ◽  
Term Evolution

The evolution of population dynamics in a stochastic environment is analysed under a general form of density-dependence with genetic variation in r and K , the intrinsic rate of increase and carrying capacity in the average environment, and in σ e 2 , the environmental variance of population growth rate. The continuous-time model assumes a large population size and a stationary distribution of environments with no autocorrelation. For a given population density, N , and genotype frequency, p , the expected selection gradient is always towards an increased population growth rate, and the expected fitness of a genotype is its Malthusian fitness in the average environment minus the covariance of its growth rate with that of the population. Long-term evolution maximizes the expected value of the density-dependence function, averaged over the stationary distribution of N . In the θ -logistic model, where density dependence of population growth is a function of N θ , long-term evolution maximizes E[ N θ ]=[1− σ e 2 /(2 r )] K θ . While σ e 2 is always selected to decrease, r and K are always selected to increase, implying a genetic trade-off among them. By contrast, given the other parameters, θ has an intermediate optimum between 1.781 and 2 corresponding to the limits of high or low stochasticity.

scholarly journals Population-level sensitivity to landscape variables reflects individual-based habitat selection in a woodland bat species

2019 ◽  
Author(s):  
Pierre-Loup Jan ◽  
Diane Zarzoso-Lacoste ◽  
Damien Fourcy ◽  
Alice Baudouin ◽  
Olivier Farcy ◽  
...  
Keyword(s):  
Growth Rate ◽  
Population Dynamics ◽  
Colony Size ◽  
Census Data ◽  
Population Level ◽  
Statistical Modelling ◽  
Positive Influence ◽  
Landscape Composition ◽  
Horseshoe Bat

AbstractUnderstanding the relationship between habitat quality and population dynamics is fundamental for long-term management and range predictions in ecology. However, habitat suitability is generally only investigated at the individual scale, as it is the case for the lesser horseshoe bat (Rhinolophus hipposideros), a species of conservation concern. Using a statistical modelling approach and census data of 94 lesser horseshoe bat colonies located in Brittany (France), we analysed the effect of landscape composition and configuration on the demography of surveyed maternity colonies (i.e. colony size, fecundity and growth rate), and compared our result to those provided by individual-based studies. Our results validated that the landscape in a 500-meter buffer around colonies (core foraging area) is crucial for population size and dynamics, and confirmed the positive influence of broadleaved woodland proportion on bat colony size. We revealed a positive effect of lakeshores and riverbanks on colony size and growth rate, underlying the importance of these habitats for the long-term conservation of this non-migratory forest species. Importantly, our results refine previous knowledge concerning the threat posed by the intensification of human activities (e.g. urbanization, agriculture, habitat fragmentation), and highlight the negative effect of large and regular patches of artificial and crop lands and of open land patches shape complexity on all demographic variables investigated. While our results support the dependence of population dynamics and associated conservation management to individual behaviour and sensitivity, environmental responses differed between the population metrics investigated, showing that efficient range prediction will require to fully grasp the complexity of the interaction between landscape and the different population dynamic parameters.

scholarly journals From individuals to populations: How intraspecific competition shapes thermal reaction norms

2019 ◽  
Author(s):  
François Mallard ◽  
Vincent Le Bourlot ◽  
Christie Le Coeur ◽  
Monique Avnaim ◽  
Romain Péronnet ◽  
...  
Keyword(s):  
Growth Rate ◽  
Population Dynamics ◽  
Intraspecific Competition ◽  
Thermal Reaction ◽  
Reaction Norms ◽  
Effect Of Temperature ◽  
Dominant Factor ◽  
List Type ◽  
Joint Effects ◽  
Effects Of Temperature

AbstractMost ectotherms follow the temperature-size rule (TSR): in cold environments individuals grow slowly but reach a large asymptotic length. Intraspecific competition can induce plastic changes of growth rate and asymptotic length and competition may itself be modulated by temperature.Our aim is to disentangle the joint effects of temperature and intraspecific competition on growth rate and asymptotic length.We used two distinct clonal lineages of the Collembola Folsomia candida, to describe thermal reaction norms of growth rate, asymptotic length and reproduction over 6 temperatures between 6°C and 29°C. In parallel, we measured the long-term size-structure and dynamics of populations reared under the same temperatures to measure growth rates and asymptotic lengths in populations and to quantify the joint effects of competition and temperature on these traits.We show that intraspecific competition modulates the temperature-size rule. In dense populations there is a direct negative effect of temperature on asymptotic length, but there is no temperature dependence of the growth rate, the dominant factor regulating growth being competition. We fail to demonstrate that the strength of competition varies with temperature except at the lowest temperature where competition is minimal. The two lineages responded differently to the joint effects of temperature and competition and these genetic differences have marked effects on population dynamics along our temperature gradient.Our results reinforce the idea that the TSR response of ectotherms can be modulated by biotic and abiotic stressors when studied in non-optimal laboratory experiments. Untangling complex interactions between environment and demography will help understanding how size will respond to environmental change and how climate change may influence population dynamics.

Russia’s Development Strategy: Guidelines and Restrictions

2008 ◽  
pp. 119-130 ◽  
Author(s):  
V. Senchagov
Keyword(s):  
Economic Development ◽  
Development Strategy ◽  
Conceptual Basis ◽  
The Core ◽  
Economic Development Strategy ◽  
Socio Economic Development ◽  
Rates Of Growth

The core of Russia’s long-term socio-economic development strategy is represented by its conceptual basis. Having considered debating points about the essence and priority of the strategy, the author analyzes the logic and stages of its development as well as possibilities, restrictions and risks of high GDP rates of growth.

Long-term population dynamics of the red deer and European roe deer at the protected and not-protected areas in Mountain Crimea

2017 ◽  
Vol 7 (4) ◽  
pp. 65-72
Author(s):  
V. N. Shmagol' ◽  
V. L. Yarysh ◽  
S. P. Ivanov ◽  
V. I. Maltsev
Keyword(s):  
Population Dynamics ◽  
Protected Areas ◽  
Red Deer ◽  
Nature Reserve ◽  
Roe Deer ◽  
Precipitation Amount ◽  
Annual Precipitation ◽  
Population Number ◽  
The Impact

<p>The long-term population dynamics of the red deer (<em>Cervus elaphus</em> L.) and European roe deer (<em>Capreolus</em> <em>capreolus</em> L.) at the mountain and forest zone of Crimea during 1980-2017 is presented. Fluctuations in numbers of both species are cyclical and partly synchronous. Period of oscillations in the population of red deer is about 25 years, the average duration of the oscillation period of number of roe deer is 12.3 years. During the fluctuations in the number the increasing and fall in population number of the red deer had been as 26-47 %, and roe deer – as 22-34 %. Basing on the dada obtained we have assumed that together with large-scale cycles of fluctuations in population number of both red deer and roe deer the short cycles of fluctuations in the number of these species with period from 3.5 to 7.5 years take place. Significant differences of the parameters of cyclical fluctuations in the number of roe deer at some sites of the Mountainous Crimea: breaches of synchronicity, as well as significant differences in the duration of cycles are revealed. The greatest deviations from the average values of parameters of long-term dynamics of the number of roe deer in Crimea are noted for groups of this species at two protected areas. At the Crimean Nature Reserve the cycle time of fluctuations of the numbers of roe deer was 18 years. At the Karadag Nature Reserve since 1976 we can see an exponential growth in number of roe deer that is continued up to the present time. By 2016 the number of roe deer reached 750 individuals at a density of 437 animals per 1 thousand ha. Peculiarity of dynamics of number of roe deer at some sites proves the existence in the mountain forest of Crimea several relatively isolated groups of deer. We assumed that "island" location of the Crimean populations of red deer and European roe deer, their relatively little number and influence of permanent extreme factors of both natural and anthropogenic origination have contributed to a mechanism of survival of these populations. The elements of such a mechanism include the following features of long-term dynamics of the population: the reduction in the period of cyclic population fluctuations, while maintaining their amplitude and the appearance of additional small cycles, providing more flexible response of the population to the impact of both negative and positive environmental factors. From the totality of the weather conditions for the Crimean population of roe deer the recurring periods of increases and downs in the annual precipitation amount may have relevance. There was a trend of increase in the roe deer population during periods of increasing annual precipitation.</p>

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