Spatial demography

2021 ◽  
pp. 259-272
Author(s):  
Guillaume Péron
Keyword(s):  
Growth Rate ◽  
Spatial Ecology ◽  
Population Distribution ◽  
Spatial Regression ◽  
Global Changes ◽  
Intrinsic Growth Rate ◽  
Distribution Models ◽  
Movement Data ◽  
Demographic Rates ◽  
Demographic Methods

Demographic methods can be used to study the spatial response of individuals and populations to current global changes. The first mechanism underlying range shifts is a change in the spatial distribution of births and deaths. The spatial regression of demographic rates with geostatistical and spatially explicit models documents the intrinsic growth rate across the range of a population. The population distribution is expected to shift towards areas with the largest intrinsic growth rate, both mechanistically and because these areas are attractive to dispersing individuals. The second mechanism is indeed movement, including emigration away from places that recently became inhospitable and immigration into newly available locations. The analysis of dispersal fluxes using movement data, or indirectly by comparing the observed and intrinsic growth rates in integrated population models, documents these fluxes. Combining these two mechanisms in integral projection models or in individual-based simulations is expected to yield major advances in predictive spatial ecology, that is, mechanistic species distribution models.

scholarly journals Continent-wide tree fecundity driven by indirect climate effects

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
James S. Clark ◽  
Robert Andrus ◽  
Melaine Aubry-Kientz ◽  
Yves Bergeron ◽  
Michal Bogdziewicz ◽  
...  
Keyword(s):  
Climate Change ◽  
Species Distribution Models ◽  
Climate Condition ◽  
Distribution Models ◽  
The West ◽  
Climate Effects ◽  
Continental Scale ◽  
Demographic Rates ◽  
Species Abundances ◽  
Meta Analyses

AbstractIndirect climate effects on tree fecundity that come through variation in size and growth (climate-condition interactions) are not currently part of models used to predict future forests. Trends in species abundances predicted from meta-analyses and species distribution models will be misleading if they depend on the conditions of individuals. Here we find from a synthesis of tree species in North America that climate-condition interactions dominate responses through two pathways, i) effects of growth that depend on climate, and ii) effects of climate that depend on tree size. Because tree fecundity first increases and then declines with size, climate change that stimulates growth promotes a shift of small trees to more fecund sizes, but the opposite can be true for large sizes. Change the depresses growth also affects fecundity. We find a biogeographic divide, with these interactions reducing fecundity in the West and increasing it in the East. Continental-scale responses of these forests are thus driven largely by indirect effects, recommending management for climate change that considers multiple demographic rates.

scholarly journals Qualitative Analysis of the Effect of Weeds Removal in Paddy Ecosystems in Fallow Season

2020 ◽  
Vol 2020 ◽  
pp. 1-12
Author(s):  
Leru Zhou ◽  
Zhigang Liu ◽  
Tiejun Zhou
Keyword(s):  
Growth Rate ◽  
Equilibrium State ◽  
Excretion Rate ◽  
Critical Value ◽  
Inorganic Fertilizer ◽  
Paddy Fields ◽  
Asymptotically Stable ◽  
Intrinsic Growth Rate ◽  
Stable Conditions ◽  
Coexistence Equilibrium

In the paper, we introduce a differential equations model of paddy ecosystems in the fallow season to study the effect of weeds removal from the paddy fields. We found that there is an unstable equilibrium of the extinction of weeds and herbivores in the system. When the intensity of weeds removal meets certain conditions and the intrinsic growth rate of herbivores is higher than their excretion rate, there is a coexistence equilibrium state in the system. By linearizing the system and using the Routh–Hurwitz criterion, we obtained the local asymptotically stable conditions of the coexistence equilibrium state. The critical value formula of the Hopf bifurcation is presented too. The model demonstrates that weeds removal from paddy fields could largely reduce the weeds biomass in the equilibrium state, but it also decreases the herbivore biomass, which probably reduces the content of inorganic fertilizer in the soil. We found a particular intensity of weeds removal that could result in the minimum content of inorganic fertilizer, suggesting weeds removal should be kept away from this intensity.

scholarly journals Using the intrinsic growth rate of the mosquito population improves spatio-temporal dengue risk estimation

Acta Tropica ◽  
2020 ◽  
Vol 208 ◽  
pp. 105519
Author(s):  
Luigi Sedda ◽  
Benjamín M. Taylor ◽  
Alvaro E. Eiras ◽  
João Trindade Marques ◽  
Rod J. Dillon
Keyword(s):  
Growth Rate ◽  
Risk Estimation ◽  
Mosquito Population ◽  
Intrinsic Growth Rate ◽  
Spatio Temporal

A performance evaluation of surplus production models with time-varying intrinsic growth in dynamic ecosystems

2019 ◽  
Vol 76 (12) ◽  
pp. 2245-2255 ◽  
Author(s):  
Geneviève M. Nesslage ◽  
Michael J. Wilberg
Keyword(s):  
Growth Rate ◽  
Time Series ◽  
Survey Data ◽  
Atlantic Menhaden ◽  
Data Sets ◽  
Time Varying ◽  
Intrinsic Growth Rate ◽  
Surplus Production ◽  
Production Models ◽  
Exploitation Rate

We conducted a simulation study to evaluate performance of surplus production models (SPMs) with a time-varying intrinsic growth rate (SPMTVr) for stocks with predation-driven changes in productivity. Data sets were simulated using an age-structured, linked, predator–prey model of Atlantic menhaden (Brevoortia tyrannus), a forage fish native to the Northwest Atlantic, and Atlantic striped bass (Morone saxatilis), its primary predator, with differing time series of fishing mortality on both predator and prey. Simulations generated test data sets for Atlantic menhaden SPMs that included either a static or time-varying intrinsic growth rate parameter. The SPMTVr largely produced more accurate, less variable estimates of exploitation rate and biomass than models with static intrinsic growth. We also applied SPMTVr to empirical Atlantic menhaden catch and survey data for 1964–2016. The SPMTVr fit the survey data well, estimated an intrinsic growth rate time series that mirrored long-term juvenile survey trends, and produced biomass and exploitation rate trends that mirrored a statistical catch-at-age model. The SPMTVr estimated dynamic, maximum sustainable yield (MSY)-based reference points that reflected changing stock productivity.

scholarly journals Demographic aspects of Chrysomya megacephala (Diptera, Calliphoridae) adults maintained under experimental conditions: reproductive rate estimates

2006 ◽  
Vol 49 (3) ◽  
pp. 457-461 ◽  
Author(s):  
Marcelo Henrique de Carvalho ◽  
Claudio José Von Zuben
Keyword(s):  
Growth Rate ◽  
Life Expectancy ◽  
Reproductive Rate ◽  
Demographic Parameters ◽  
Intrinsic Growth Rate ◽  
Experimental Conditions ◽  
Chrysomya Megacephala ◽  
Finite Growth ◽  
Life Expectancy Estimate ◽  
Age Estimates

The objective of this work was to evaluate some aspects of the populational ecology of Chrysomya megacephala, analyzing demographic aspects of adults kept under experimental conditions. Cages of C. megacephala adults were prepared with four different larval densities (100, 200, 400 and 800). For each cage, two tables were made: one with demographic parameters for the life expectancy estimate at the initial age (e0), and another with the reproductive rate and average reproduction age estimates. Populational parameters such as the intrinsic growth rate (r) and the finite growth rate (lambda) were calculated as well.

Doses of darkness control latitudinal differences in breeding date in the barnacle Semibalanus balanoides

2005 ◽  
Vol 85 (1) ◽  
pp. 59-63 ◽  
Author(s):  
J. Davenport ◽  
M.S. Berggren ◽  
T. Brattegard ◽  
N. Brattenborg ◽  
M. Burrows ◽  
...  
Keyword(s):  
Cloud Cover ◽  
Population Distribution ◽  
Day Length ◽  
Egg Mass ◽  
Global Changes ◽  
Timing Of Breeding ◽  
Semibalanus Balanoides ◽  
Southern Limit ◽  
Breeding Date ◽  
Geographical Scale

This paper reports the first study of breeding in the boreo-arctic barnacle Semibalanus balanoides in which latitudinal variation in timing of egg mass hardening has been examined simultaneously over the geographical scale involved, thereby excluding temporal confounding of the data. The timing of autumn egg mass hardening on the middle shore was established in 2002 and 2003 at ten stations ranging latitudinally from Trondheim (63°24′N) to Plymouth (50°18′N). To assess variation at local scale (<10 km), breeding was studied on three shores at each of two Irish locations (Cork and Galway). At Oban (Scotland) and Cork, the effect of shore height on timing of breeding was investigated. A strong influence of latitude and day length on timing of breeding was found in both 2002 and 2003. In both years, barnacles bred much earlier (when day length was longer) at high rather than low latitudes. No significant effect of environmental temperature or insolation on timing of breeding was detected. Shores no more than 10 km apart showed minimal difference in middle shore breeding date (<4 days). However, upper shore barnacles bred significantly earlier (by 7–13 days) than middle shore animals. The data indicate that breeding is controlled by period of daily darkness, with high shore animals encountering longer effective ‘nights’ because of the opercular closure response to emersion (which will reduce light penetration to tissues). Predictions concerning the effects of global changes in climate and cloud cover on breeding and population distribution are made. It is suggested that increased cloud cover in the northern hemisphere is likely to induce earlier breeding, and possibly shift the present southern limit of Semibalanus southwards.

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