Relative importance of climate, habitat, and species' traits on population dynamics

2016 ◽  
Author(s):  
Georgina Palmer
Keyword(s):  
Population Dynamics ◽  
Species Traits ◽  
Relative Importance

Life history and environmental influences on population dynamics in sockeye salmon

2014 ◽  
Vol 71 (8) ◽  
pp. 1198-1208 ◽  
Author(s):  
Douglas C. Braun ◽  
John D. Reynolds
Keyword(s):  
Population Dynamics ◽  
Life History ◽  
Population Growth ◽  
Growth Rates ◽  
Environmental Conditions ◽  
Sockeye Salmon ◽  
Life History Traits ◽  
Relative Importance ◽  
Population Growth Rates ◽  
Habitat Variables

Understanding linkages among life history traits, the environment, and population dynamics is a central goal in ecology. We compared 15 populations of sockeye salmon (Oncorhynchus nerka) to test general hypotheses for the relative importance of life history traits and environmental conditions in explaining variation in population dynamics. We used life history traits and habitat variables as covariates in mixed-effect Ricker models to evaluate the support for correlates of maximum population growth rates, density dependence, and variability in dynamics among populations. We found dramatic differences in the dynamics of populations that spawn in a small geographical area. These differences among populations were related to variation in habitats but not life history traits. Populations that spawned in deep water had higher and less variable population growth rates, and populations inhabiting streams with larger gravels experienced stronger negative density dependence. These results demonstrate, in these populations, the relative importance of environmental conditions and life histories in explaining population dynamics, which is rarely possible for multiple populations of the same species. Furthermore, they suggest that local habitat variables are important for the assessment of population status, especially when multiple populations with different dynamics are managed as aggregates.

scholarly journals The relative importance of direct and indirect effects of hunting mortality on the population dynamics of brown bears

2015 ◽  
Vol 282 (1798) ◽  
pp. 20141840 ◽  
Author(s):  
Jacinthe Gosselin ◽  
Andreas Zedrosser ◽  
Jon E. Swenson ◽  
Fanie Pelletier
Keyword(s):  
Population Dynamics ◽  
Population Growth ◽  
Indirect Effects ◽  
Ursus Arctos ◽  
Brown Bear ◽  
Relative Importance ◽  
Direct And Indirect Effects ◽  
Negative Effects ◽  
Hunting Pressure ◽  
Demographic Rates

There is increasing evidence of indirect effects of hunting on populations. In species with sexually selected infanticide (SSI), hunting may decrease juvenile survival by increasing male turnover. We aimed to evaluate the relative importance of direct and indirect effects of hunting via SSI on the population dynamics of the Scandinavian brown bear ( Ursus arctos ). We performed prospective and retrospective demographic perturbation analyses for periods with low and high hunting pressures. All demographic rates, except yearling survival, were lower under high hunting pressure, which led to a decline in population growth under high hunting pressure ( λ = 0.975; 95% CI = 0.914–1.011). Hunting had negative indirect effects on the population through an increase in SSI, which lowered cub survival and possibly also fecundity rates. Our study suggests that SSI could explain 13.6% of the variation in population growth. Hunting also affected the relative importance of survival and fecundity of adult females for population growth, with fecundity being more important under low hunting pressure and survival more important under high hunting pressure. Our study sheds light on the importance of direct and indirect effects of hunting on population dynamics, and supports the contention that hunting can have indirect negative effects on populations through SSI.

scholarly journals Multimodel inference to quantify the relative importance of abiotic factors in the population dynamics of marine zooplankton

2018 ◽  
Vol 181 ◽  
pp. 91-98 ◽  
Author(s):  
Gert Everaert ◽  
Yana Deschutter ◽  
Marleen De Troch ◽  
Colin R. Janssen ◽  
Karel De Schamphelaere
Keyword(s):  
Population Dynamics ◽  
Abiotic Factors ◽  
Relative Importance ◽  
Multimodel Inference ◽  
Marine Zooplankton

scholarly journals Decomposing variation in population growth into contributions from environment and phenotypes in an age-structured population

2011 ◽  
Vol 279 (1727) ◽  
pp. 394-401 ◽  
Author(s):  
Fanie Pelletier ◽  
Kelly Moyes ◽  
Tim H. Clutton-Brock ◽  
Tim Coulson
Keyword(s):  
Population Dynamics ◽  
Population Growth ◽  
Age Structure ◽  
Life History Traits ◽  
Population Fluctuations ◽  
Relative Importance ◽  
Ecological Interactions ◽  
Structured Population ◽  
Individual Covariates ◽  
Age Structured

Evaluating the relative importance of ecological drivers responsible for natural population fluctuations in size is challenging. Longitudinal studies where most individuals are monitored from birth to death and where environmental conditions are known provide a valuable resource to characterize complex ecological interactions. We used a recently developed approach to decompose the observed fluctuation in population growth of the red deer population on the Isle of Rum into contributions from climate, density and their interaction and to quantify their relative importance. We also quantified the contribution of individual covariates, including phenotypic and life-history traits, to population growth. Fluctuations in composition in age and sex classes ((st)age structure) of the population contributed substantially to the population dynamics. Density, climate, birth weight and reproductive status contributed less and approximately equally to the population growth. Our results support the contention that fluctuations in the population's (st)age structure have important consequences for population dynamics and underline the importance of including information on population composition to understand the effect of human-driven changes on population performance of long-lived species.

scholarly journals Die Treiber der räumlichen Emergenz und Konzentration der Photovoltaik- Industrie in Deutschland

2015 ◽  
Vol 59 (3) ◽  
Author(s):  
Moritz Breul ◽  
Tom Broekel ◽  
Matthias Brachert
Keyword(s):  
Population Dynamics ◽  
Life Cycle ◽  
Relative Importance ◽  
Beneficial Effects ◽  
Industry Life Cycle ◽  
Regional Concentration ◽  
Early Phases ◽  
Shed Light ◽  
Unique Dataset

The drivers of the spatial emergence and clustering of the photovoltaic industry in Germany. Following the relatedness literature, we explore to what extent related industries influenced the regional emergence of the photovoltaic (PV) industry. In addition, we shed light on factors explaining selective processes of clustering. We particularly argue that generic resources and resources of related activities have been crucial for the regional concentration in early phases of the industry life cycle. With increasing maturity, industry-specific resources became more important. Based on a unique dataset containing population dynamics of the German PV industry, the hypotheses are tested empirically. Our results partially confirm the assumed beneficial effects of related industries for the emergence of the PV industry. Moreover, we observe changes in the relative importance of factors supporting regional concentration, with industry-specific resources becoming dominant as the industry matures.

scholarly journals Linking multi-level population dynamics: trait, role, and population

2020 ◽  
Author(s):  
Nao Takashina
Keyword(s):  
Population Dynamics ◽  
Species Interactions ◽  
Population Level ◽  
Species Traits ◽  
Trophic Niche ◽  
Niche Shift ◽  
Mathematical Framework ◽  
Ecosystem Structure ◽  
Level Model ◽  
Role Shift

Species interactions characterize population dynamics and ecosystem structure. While the population-level discussion is common in many ecological studies, trait variations within a population and ontogenetic diet/trophic niche shift are prevail across taxa. The ontogenetic development may lead to an individual’s role shift, such as inferior/superior competitor, prey, or predator. Here, we develop a novel mathematical framework to bridge multiple levels of population dynamics, such as trait, role, and population-level. We start with a nonlinear trait-level model, and derive role-level and population-level dynamics. By utilizing the connections, we demonstrate that the population-level model predicts the equilibrium status of the role-level model. In the role-level model, we discuss multiple role-shift scenarios: from (i) inferior/superior competitor to superior/inferior competitor, (ii) competitor to predator, and (iii) prey to predator. Our approach connects traits, roles, and population dynamics consistently, thus offering an opportunity to discuss the effect of species traits in the population-level dynamics.

scholarly journals The relative importance of seed competition, resource competition and perturbations on community structure

2011 ◽  
Vol 8 (5) ◽  
pp. 1107-1120 ◽  
Author(s):  
K. Bohn ◽  
J. G. Dyke ◽  
R. Pavlick ◽  
B. Reineking ◽  
B. Reu ◽  
...  
Keyword(s):  
Population Dynamics ◽  
Community Structure ◽  
Resource Competition ◽  
Regional Climate ◽  
Global Scale ◽  
Relative Importance ◽  
Plant Strategies ◽  
Primary Selection ◽  
Growth And Reproduction ◽  
Do So

Abstract. While the regional climate is the primary selection pressure for whether a plant strategy can survive, however, competitive interactions strongly affect the relative abundances of plant strategies within communities. Here, we investigate the relative importance of competition and perturbations on the development of vegetation community structure. To do so, we develop DIVE (Dynamics and Interactions of VEgetation), a simple general model that links plant strategies to their competitive dynamics, using growth and reproduction characteristics that emerge from climatic constraints. The model calculates population dynamics based on establishment, mortality, invasion and exclusion in the presence of different strengths of perturbations, seed and resource competition. The highest levels of diversity were found in simulations without competition as long as mortality is not too high. However, reasonable successional dynamics were only achieved when resource competition is considered. Under high levels of competition, intermediate levels of perturbations were required to obtain coexistence. Since succession and coexistence are observed in plant communities, we conclude that the DIVE model with competition and intermediate levels of perturbation represents an adequate way to model population dynamics. Because of the simplicity and generality of DIVE, it could be used to understand vegetation structure and functioning at the global scale and the response of vegetation to global change.

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