scholarly journals A demographic model to predict future growth of the Addo elephant population

Koedoe ◽  
1999 ◽  
Vol 42 (1) ◽  
Author(s):  
A.M. Woodd
Keyword(s):  
Population Size ◽  
National Park ◽  
Target Population ◽  
Demographic Model ◽  
Elephant Population ◽  
Age Structured ◽  
Term Data ◽  
Future Population ◽  
Future Growth

An age-structured demographic model of the growth of the Addo elephant population was developed using parameters calculated from long-term data on the population. The model was used to provide estimates of future population growth. Expansion of the Addo Elephant National Park is currently underway, and the proposed target population size for elephant within the enlarged park is 2700. The model predicts that this population size will be reached during the year 2043, so that the Addo elephant population can continue to increase for a further 44 years before its target size within the enlarged park is attained.

Bonobo population dynamics: Past patterns and future predictions for the Lola ya Bonobo population using demographic modelling

2018 ◽  
Author(s):  
Lisa J. Faust ◽  
Claudine André ◽  
Raphaël Belais ◽  
Fanny Minesi ◽  
Zjef Pereboom ◽  
...  
Keyword(s):  
Population Dynamics ◽  
Pan Troglodytes ◽  
Growth Trajectories ◽  
Demographic Model ◽  
Pan African ◽  
Demographic Modelling ◽  
Projected Changes ◽  
Demographic Patterns ◽  
Future Population ◽  
Future Growth

Wildlife sanctuaries rescue, rehabilitate, reintroduce and provide life-long care for orphaned and injured animals. Understanding a sanctuary’s population dynamics—patterns in arrival, mortality and projected changes in population size—allows careful planning for future needs. Building on previous work on the population dynamics of chimpanzees (Pan troglodytes) in sanctuaries of the Pan African Sanctuary Alliance (PASA; Faust et al. 2011), this chapter extends analyses to the only PASA bonobo sanctuary. Its authors analysed historic demographic patterns and projected future population dynamics using an individual-based demographic model. The population has been growing at 6.7 per cent per year, driven by arrivals of new individuals (mean = 5.5 arrivals per year). Several model scenarios projecting varying arrival rates, releases and breeding scenarios clarify potential future growth trajectories for the sanctuary. This research illustrates how data on historic dynamics can be modelled to inform future sanctuary capacity and management needs. Les sanctuaires de faune secourent, réhabilitent, réintroduisent, et fournissent des soins pour toute la vie aux animaux orphelins et blessés. Comprendre les dynamiques de la population d’un sanctuaire—les motifs d’arrivée, mortalité, et de changements projetés de la taille de la population—permet une planification prudente pour les nécessités du futur. En se basant sur le travail déjà fait sur les dynamiques de la population chimpanzé (Pan troglodytes) dans les sanctuaires du Pan African Sanctuary Alliance (PASA; Faust et al. 2011), nous étendons notre analyse au seul sanctuaire bonobo par PASA. Nous avons analysé les motifs démographiques historiques et avons projeté les futures dynamiques de la population en utilisant un modèle démographique basé sur l’individu. La population augmente de 6.7 per cent par an, poussée par l’arrivée de nouveaux individus (moyenne = 5.5 arrivées par an). Plusieurs scénarios modèles montrent une trajectoire de potentielle croissance pour le sanctuaire. Cette recherche illustre comment modeler les données sur les dynamiques historiques pour informer la capacité future du sanctuaire et les besoins gestionnaires.

scholarly journals Quantifying whether different demographic models produce incongruent results on population dynamics of two long-term studied rodent species

2017 ◽  
Vol 3 (1) ◽  
pp. 18-26
Author(s):  
Giovanni Amori ◽  
Valentina De Silvestro ◽  
Paolo Ciucci ◽  
Luca Luiselli
Keyword(s):  
Population Dynamics ◽  
Population Density ◽  
Population Size ◽  
Myodes Glareolus ◽  
Suitable Model ◽  
Demographic Model ◽  
Apodemus Flavicollis ◽  
Demographic Models ◽  
Long Term Studies

Abstract1. Population density (ind/ha) of long-term (>15 years) series of CMR populations, using distinct demographic models designed for both open and closed populations, were analysed for two sympatric species of rodents (Myodes glareolus and Apodemus flavicollis) from a mountain area in central Italy, in order to test the relative performance of various employed demographic models. In particular, the hypothesis that enumeration models systematically underestimate the population size of a given population was tested.2. Overall, we compared the performance of 7 distinct demographic models, including both closed and open models, for each study species. Although the two species revealed remarkable intrinsic differences in demography traits (for instance, a lower propensity for being recaptured in Apodemus flavicollis), the Robust Design appeared to be the best fitting model, showing that it is the most suitable model for long-term studies.3. Among the various analysed demographic models, Jolly-Seber returned the lower estimates of population density for both species. Thus, this demographic model could not be suggested for being applied for long-term studies of small mammal populations because it tends to remarkably underestimate the effective population size. Nonetheless, yearly estimates of population density by Jolly-Seber correlated positively with yearly estimates of population density by closed population models, thus showing that interannual trends in population dynamics were uncovered by both types of demographic models, although with different values in terms of true population size.

scholarly journals The impact of burning on lion Panthera leo habitat choice in an African savanna

2013 ◽  
Vol 59 (3) ◽  
pp. 335-339 ◽  
Author(s):  
Stephanie Eby ◽  
Anna Mosser ◽  
Ali Swanson ◽  
Craig Packer ◽  
Mark Ritchie
Keyword(s):  
National Park ◽  
Habitat Choice ◽  
Territory Size ◽  
Short Term ◽  
Data Set ◽  
Burned Areas ◽  
The Impact ◽  
Term Data ◽  
Prey Attraction

Abstract Carnivores play a central role in ecosystem processes by exerting top-down control, while fire exerts bottom-up control in ecosystems throughout the world, yet, little is known about how fire affects short-term carnivore distributions across the landscape. Through the use of a long-term data set we investigated the distribution of lions, during the daytime, in relation to burned areas in Serengeti National Park, Tanzania. We found that lions avoid burned areas despite the fact that herbivores, their prey, are attracted to burned areas. Prey attraction, however, likely results from the reduction in cover caused by burning, that may thereby decrease lion hunting success. Lions also do not preferentially utilize the edges of burned areas over unburned areas despite the possibility that edges would combine the benefit of cover with proximity to abundant prey. Despite the fact that lions avoid burned areas, lion territory size and reproductive success were not affected by the proportion of the territory burned each year. Therefore, burning does not seem to reduce lion fitness perhaps because of the heterogeneity of burned areas across the landscape or because it is possible that when hunting at night lions visit burned areas despite their daytime avoidance of these areas.

scholarly journals Correlations in fertility across generations: can low fertility persist?

2014 ◽  
Vol 281 (1779) ◽  
pp. 20132561 ◽  
Author(s):  
Martin Kolk ◽  
Daniel Cownden ◽  
Magnus Enquist
Keyword(s):  
Population Size ◽  
Empirical Studies ◽  
Fertility Transition ◽  
Low Fertility ◽  
Major Influence ◽  
The Future ◽  
Intergenerational Correlations ◽  
Over Time ◽  
Future Population

Correlations in family size across generations could have a major influence on human population size in the future. Empirical studies have shown that the associations between the fertility of parents and the fertility of children are substantial and growing over time. Despite their potential long-term consequences, intergenerational fertility correlations have largely been ignored by researchers. We present a model of the fertility transition as a cultural process acting on new lifestyles associated with fertility. Differences in parental and social influences on the acquisition of these lifestyles result in intergenerational correlations in fertility. We show different scenarios for future population size based on models that disregard intergenerational correlations in fertility, models with fertility correlations and a single lifestyle, and models with fertility correlations and multiple lifestyles. We show that intergenerational fertility correlations will result in an increase in fertility over time. However, present low-fertility levels may persist if the rapid introduction of new cultural lifestyles continues into the future.

Can a common snake provide conservation insights?

2018 ◽  
Vol 66 (4) ◽  
pp. 279
Author(s):  
Ross L. Goldingay
Keyword(s):  
Threatened Species ◽  
National Park ◽  
Habitat Restoration ◽  
Rock Outcrops ◽  
Limited Availability ◽  
Eastern Australia ◽  
Site Use ◽  
Habitat Generalist ◽  
Term Data

The small-eyed snake (Cryptophis nigrescens) is a common non-threatened species in eastern Australia. It coexists with the threatened broad-headed snake (Hoplocephalus bungaroides), a species adversely affected by habitat disturbance and subject to poaching. The small-eyed snake is a habitat generalist and not subject to poaching. It may prey on other snakes, including the broad-headed snake, and, like the broad-headed snake, may shelter under thermally favourable loose rocks during the cooler months of the year. This may lead to interactions between these species due to the limited availability of such rocks, and possibly exacerbate other threats to the broad-headed snake, such as poaching and the loss of thermally favourable rocks. I conducted repeat surveys for snakes at 64 rock outcrops in Royal National Park over a 16-year period. I predicted that site use by the small-eyed snake would not be influenced by a disturbance variable previously documented to influence site use by the broad-headed snake. Observations were consistent with this prediction, confirming the unique vulnerability of the broad-headed snake. I used my long-term data to analyse the co-occurrence of the two species. The broad-headed snake was detected as frequently at sites with and without the small-eyed snake, suggesting that these species occupy outcrops independently of each other. Therefore, interactions with the small-eyed snake will not reduce the effectiveness of habitat restoration for the broad-headed snake in Royal National Park.

scholarly journals Target regional size and structure of the population of the Russian Federation: possibilities to identify and achieve

2019 ◽  
Vol 3 (4) ◽  
pp. 30-44
Author(s):  
Ekaterina A. Edinak ◽  
Andrey G. Korovkin ◽  
Ivan B. Korolev
Keyword(s):  
Population Size ◽  
Russian Federation ◽  
Labour Productivity ◽  
Federal District ◽  
Target Population ◽  
Regional Population ◽  
The Russian Federation ◽  
Far Eastern ◽  
Size And Structure

Abstract The article proposes a solution of the task of achieving the target regional population size and structure, which would be sustainable in the long term, by means of managing its movement. The significance of this task is justified by the growing concentration of population and labour in a few number of Russia’s regions in the current and projected periods, primarily due to migration processes. The apparatus of matrix equations is used to shape the conditions for reaching the target size and structure of the population. The article presents the estimates of the equilibrium population of the Russian Federation and the possibilities of reaching the target population size in prospect. The demographic forecast of Rosstat up to 2035 in three variants is considered as a target. For each of variants, the required increase of population via birth and immigration is calculated. The possibilities to assess the need in population inflow and to achieve the target population size by using the methodology proposed in the article are shown by the case of the Far Eastern Federal District. It is argued that nowadays a crucial element of social and economic policy in the regions should be creation of new jobs with higher labour productivity and therefore, reduction of the need for foreign labour migrants in the Russian labour market.

When Did the Human Population Size Start Increasing?

Genetics ◽  
2000 ◽  
Vol 155 (4) ◽  
pp. 1865-1874 ◽  
Author(s):  
Jeffrey D Wall ◽  
Molly Przeworski
Keyword(s):  
Population Size ◽  
Growth Parameters ◽  
Balancing Selection ◽  
Upper Paleolithic ◽  
Population Subdivision ◽  
Data Sets ◽  
Demographic Model ◽  
Frequency Spectra ◽  
Constant Population Size

Abstract We analyze the frequency spectra of all available human nuclear sequence data sets by using a model of constant population size followed by exponential growth. Parameters of growth (more extreme than or) comparable to what has been suggested from mtDNA data can be rejected for 6 out of the 10 largest data sets. When the data are separated into African and non-African samples, a constant size no-growth model can be rejected for 4 out of 8 non-African samples. Long-term growth (i.e., starting 50–100 kya) can be rejected for 2 out of 8 African samples and 5 out of 8 non-African ones. Under more complex demographic models, including a bottleneck or population subdivision, more of the data are compatible with long-term growth. One problem with the data used here is that a subset of loci may reflect the action of natural selection as well as of demography. It remains possible that the correct demographic model is one of constant population size followed by long-term growth but that at several loci the demographic signature has been obscured by balancing or diversifying selection. However, it is not clear that the data at these loci are consistent with a simple model of balancing selection; more complicated selective alternatives cannot be tested unless they are made explicit. An alternative explanation is that population size growth is more recent (e.g., upper Paleolithic) and that some of the loci have experienced recent directional selection. Given the available data, the latter hypothesis seems more likely.

Trade-offs in plankton species richness arising from drought: insights from long-term data of a National Park wetland (central Spain)

2012 ◽  
Vol 21 (10) ◽  
pp. 2453-2476 ◽  
Author(s):  
Carmen Rojo ◽  
Miguel Álvarez-Cobelas ◽  
José Benavent-Corai ◽  
María Mercedes Barón-Rodríguez ◽  
María A. Rodrigo
Keyword(s):  
Species Richness ◽  
National Park ◽  
Central Spain ◽  
Trade Offs ◽  
Term Data ◽  
Plankton Species

scholarly journals Sampling bias exaggerates a textbook example of a trophic cascade

2020 ◽  
Author(s):  
Elaine M. Brice ◽  
Eric J. Larsen ◽  
Daniel R. MacNulty
Keyword(s):  
Populus Tremuloides ◽  
Canis Lupus ◽  
Trophic Cascade ◽  
National Park ◽  
Large Scale ◽  
Sampling Bias ◽  
Scientific Challenge ◽  
Large Predators ◽  
Term Data

AbstractUnderstanding how wildland ecosystems respond to the loss and recovery of large predators is vital to decipher the forces that structure food webs and to guide the practice of ecosystem conservation, restoration, and rewilding. This is a major scientific challenge, however, because these large-scale, uncontrolled systems are difficult (or impossible) to sample properly. We show how a tradition of nonrandom sampling has confounded this understanding in a textbook system (Yellowstone National Park) where carnivore [wolf (Canis lupus)] recovery is often associated with a trophic cascade involving changes in herbivore [elk (Cervus canadensis)] behavior and density that promote plant regeneration. Long-term data indicate that a customary practice of sampling only the tallest young plants overestimated regeneration of aspen (Populus tremuloides) by a factor of 3-44 compared to random sampling. Our results demonstrate how seemingly minor departures from principled sampling can generate substantial misunderstandings about the strength of trophic cascades caused by large terrestrial predators.

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