scholarly journals Contrasting effects of climate on grey heron, malleefowl and barn owl populations

2012 ◽  
Vol 39 (1) ◽  
pp. 7 ◽  
Author(s):  
Maria Boyle ◽  
Jim Hone
Keyword(s):  
Growth Rate ◽  
Population Dynamics ◽  
Population Growth ◽  
Population Growth Rate ◽  
Bird Species ◽  
Barn Owl ◽  
Annual Rainfall ◽  
Future Climate Change ◽  
Published Data ◽  
Grey Heron

Context The population dynamics of many wildlife species are associated with fluctuations in climate. Food and abundance may also influence wildlife dynamics. Aims The present paper aims to evaluate the relative effects of climate on the annual instantaneous population growth rate (r) of the following three bird species: grey heron and barn owl in parts of Britain and malleefowl in a part of Australia. Methods A priori hypotheses of mechanistic effects of climate are derived and evaluated using information theoretic and regression analyses and published data for the three bird species. Climate was measured as the winter North Atlantic Oscillation (NAO) for herons and owls, and rainfall and also the Southern Oscillation Index (SOI) for malleefowl. Key results Population dynamics of grey heron were positively related to the winter NAO, and of malleefowl were positively related to annual rainfall and related in a non-linear manner to SOI. By contrast, population dynamics of barn owl were very weakly related to climate. The best models for the grey heron differed between time periods but always included an effect of the NAO. Conclusions The annual population growth rate of grey heron, malleefowl and barn owl show contrasting relationships with climate, from stronger (heron and malleefowl) to weaker (barn owl). The results were broadly consistent with reported patterns but differed in some details. Interpretation of the effects of climate on the basis of analyses rather than visual assessment is encouraged. Implications Effects of climate differ among species, so effects of future climate change may also differ.

scholarly journals Breeding transients in capture–recapture modeling and their consequences for local population dynamics

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Daniel Oro ◽  
Daniel F. Doak
Keyword(s):  
Growth Rate ◽  
Population Dynamics ◽  
Population Growth ◽  
Population Growth Rate ◽  
Local Population ◽  
Environmental Stochasticity ◽  
Adult Survival ◽  
Local Survival ◽  
First Reproduction ◽  
Capture Recapture

Abstract Standard procedures for capture–mark–recapture modelling (CMR) for the study of animal demography include running goodness-of-fit tests on a general starting model. A frequent reason for poor model fit is heterogeneity in local survival among individuals captured for the first time and those already captured or seen on previous occasions. This deviation is technically termed a transience effect. In specific cases, simple, uni-state CMR modeling showing transients may allow researchers to assess the role of these transients on population dynamics. Transient individuals nearly always have a lower local survival probability, which may appear for a number of reasons. In most cases, transients arise due to permanent dispersal, higher mortality, or a combination of both. In the case of higher mortality, transients may be symptomatic of a cost of first reproduction. A few studies working at large spatial scales actually show that transients more often correspond to survival costs of first reproduction rather than to permanent dispersal, bolstering the interpretation of transience as a measure of costs of reproduction, since initial detections are often associated with first breeding attempts. Regardless of their cause, the loss of transients from a local population should lower population growth rate. We review almost 1000 papers using CMR modeling and find that almost 40% of studies fitting the searching criteria (N = 115) detected transients. Nevertheless, few researchers have considered the ecological or evolutionary meaning of the transient phenomenon. Only three studies from the reviewed papers considered transients to be a cost of first reproduction. We also analyze a long-term individual monitoring dataset (1988–2012) on a long-lived bird to quantify transients, and we use a life table response experiment (LTRE) to measure the consequences of transients at a population level. As expected, population growth rate decreased when the environment became harsher while the proportion of transients increased. LTRE analysis showed that population growth can be substantially affected by changes in traits that are variable under environmental stochasticity and deterministic perturbations, such as recruitment, fecundity of experienced individuals, and transient probabilities. This occurred even though sensitivities and elasticities of these parameters were much lower than those for adult survival. The proportion of transients also increased with the strength of density-dependence. These results have implications for ecological and evolutionary studies and may stimulate other researchers to explore the ecological processes behind the occurrence of transients in capture–recapture studies. In population models, the inclusion of a specific state for transients may help to make more reliable predictions for endangered and harvested species.

Effects of territorial status and life history on Sandhill Crane (Antigone canadensis) population dynamics in south-central Wisconsin, USA

2019 ◽  
Vol 97 (2) ◽  
pp. 112-120 ◽  
Author(s):  
Michael E. Wheeler ◽  
Jeb A. Barzen ◽  
Shawn M. Crimmins ◽  
Timothy R. Van Deelen
Keyword(s):  
Growth Rate ◽  
Population Growth ◽  
Population Growth Rate ◽  
Demographic Data ◽  
Bird Species ◽  
Adult Survival ◽  
Vital Rates ◽  
Management Actions ◽  
South Central ◽  
Sandhill Cranes

Population growth rate in long-lived bird species is often most sensitive to changes in adult survival. Sandhill Cranes (Antigone canadensis (Linnaeus, 1758)) have long life spans, small broods, and delayed first reproduction. Only territorial adult Sandhill Cranes participate in breeding, and territory acquisition reflects the interplay between the availability of suitable territories and the variation in mortality of adult birds occupying those territories. We estimated vital rates of a population at equilibrium using long-term resightings data (2000–2014; n = 451 marked individuals) in a multistate mark–resight model and used a stage-structured projection matrix to assess how strongly territorial adult survival affects population growth rate. Elasticity analysis indicated territorial birds surviving and retaining territories had a 2.58 times greater impact on population growth compared with the next most important transition rate (survival of nonterritorial adults remaining nonterritorial). Knowing how changes in vital rates of various stage classes will differentially impact population growth rate allows for targeted management actions including encouraging growth in recovering populations, assessing opportunity for recreational harvest, or maintaining populations at a desired level. This study also highlights the value of collecting demographic data for all population segments, from which one can derive reproductive output or growth rate.

scholarly journals Population growth rates: issues and an application

2002 ◽  
Vol 357 (1425) ◽  
pp. 1307-1319 ◽  
Author(s):  
H. Charles J. Godfray ◽  
Mark Rees
Keyword(s):  
Growth Rate ◽  
Population Dynamics ◽  
Population Growth ◽  
Growth Rates ◽  
Population Growth Rate ◽  
Population Change ◽  
Evolutionarily Stable Strategy ◽  
Model Systems ◽  
Population Growth Rates

Current issues in population dynamics are discussed in the context of The Royal Society Discussion Meeting 'Population growth rate: determining factors and role in population regulation'. In particular, different views on the centrality of population growth rates to the study of population dynamics and the role of experiments and theory are explored. Major themes emerging include the role of modern statistical techniques in bringing together experimental and theoretical studies, the importance of long-term experimentation and the need for ecology to have model systems, and the value of population growth rate as a means of understanding and predicting population change. The last point is illustrated by the application of a recently introduced technique, integral projection modelling, to study the population growth rate of a monocarpic perennial plant, its elasticities to different life-history components and the evolution of an evolutionarily stable strategy size at flowering.

Population Dynamics of Crenate Broomrape (Orobanche crenata) in Faba Bean (Vicia faba)

Weed Science ◽  
1993 ◽  
Vol 41 (4) ◽  
pp. 563-567 ◽  
Author(s):  
Francisca Lopez-Granados ◽  
Luis Garcia-Torres
Keyword(s):  
Growth Rate ◽  
Population Dynamics ◽  
Population Density ◽  
Population Growth ◽  
Faba Bean ◽  
Population Growth Rate ◽  
Spatial Dispersion ◽  
Climatic Conditions ◽  
Orobanche Crenata ◽  
Soil Temperatures

Progression of crenate broomrape population density (PD, number of emerged plants m-2) in faba bean was studied over 8 yr in Spain. Spatial dispersion and effect of climatic conditions on parasite population growth rate (PGR) also were studied. With repeated cropping of faba bean, infestations of crenate broomrape increased from an initial PD of 0.15 to an average of 26, with a maximum of about 40 to 45. The average population growth rate (PGR, ratio between the PD of any 2 consecutive years) was approximately 3. However, this figure varied widely among localities and years, from 0.8 to 7.7. A highly significant relationship (P = 0.01) was found between PGR and rainfall and soil temperatures during December to February, months of crop vegetative growth. Dispersion of crenate broomrape infestations mainly followed direction of crop rows, most likely due to the effect of tillage and harvesting operations, which were the same direction as sowing.

scholarly journals Annual Mortality Limit for Four Gull Species in the Atlantic Flyway

2021 ◽  
Vol 12 (2) ◽  
pp. 453-463
Author(s):  
Mark E. Seamans ◽  
Chris Dwyer
Keyword(s):  
Growth Rate ◽  
Population Growth ◽  
Population Growth Rate ◽  
Demographic Data ◽  
Bird Species ◽  
Recovery Factor ◽  
Herring Gulls ◽  
Colonial Nesting ◽  
Atlantic Flyway ◽  
Laughing Gulls

Abstract We estimated the allowable annual take of great black-backed gulls Larus marinus, herring gulls L. argentatus, ring-billed gulls L. delawarensis, and laughing gulls Leucophaeus atricilla in the U.S. portion of the Atlantic Flyway to help meet human safety and resource management goals. Gulls can pose a serious threat to aviation, negatively impact other colonial-nesting migratory bird species, and conflict with other human activities. We estimated an annual take limit using a model that incorporated intrinsic population growth rate, minimum population size, and a recovery factor for each species. We estimated intrinsic population growth by combining allometric with life table approaches. We used the recovery factor to restrict the take level of the great black-backed gull beyond that of the other species because of poor data quality and concern about its population status. The herring gull was the only species with comprehensive demographic data. Population sizes used in estimating potential take limit varied greatly among the four species, but estimates of intrinsic population growth rate were similar (range 0.118 to 0.197). The annual potential take limits for the four gull species were 7,963 for herring gulls, 2,081 for great black-backed gulls, 15,039 for laughing gulls, and 14,826 for ring-billed gulls. Comparing average annual take from 2012–2019 to our modeled potential take limit, overharvest has not occurred for great black-backed and laughing gulls, occurred once every 8 y for ring-billed gulls, and occurred over half the time for herring gulls.

scholarly journals Demographic, mechanistic and density–dependent determinants of population growth rate: a case study in an avian predator

2002 ◽  
Vol 357 (1425) ◽  
pp. 1171-1177 ◽  
Author(s):  
Jim Hone ◽  
Richard M. Sibly
Keyword(s):  
Growth Rate ◽  
Population Growth ◽  
Food Availability ◽  
Population Growth Rate ◽  
Barn Owl ◽  
Numerical Response ◽  
Avian Predator ◽  
Density Dependent ◽  
Juvenile Mortality ◽  
Demographic Rates

Identifying the determinants of population growth rate is a central topic in population ecology. Three approaches (demographic, mechanistic and density–dependent) used historically to describe the determinants of population growth rate are here compared and combined for an avian predator, the barn owl ( Tyto alba ). The owl population remained approximately stable ( r ≈ 0) throughout the period from 1979 to 1991. There was no evidence of density dependence as assessed by goodness of fit to logistic population growth. The finite (λ) and instantaneous ( r ) population growth rates were significantly positively related to food (field vole) availability. The demographic rates, annual adult mortality, juvenile mortality and annual fecundity were reported to be correlated with vole abundance. The best fit ( R 2 = 0.82) numerical response of the owl population described a positive effect of food (field voles) and a negative additive effect of owl abundance on r . The numerical response of the barn owl population to food availability was estimated from both census and demographic data, with very similar results. Our analysis shows how the demographic and mechanistic determinants of population growth rate are linked; food availability determines demographic rates, and demographic rates determine population growth rate. The effects of food availability on population growth rate are modified by predator abundance.

Seasonal variation in the population growth rate of a dominant zooplankter: what determines its population dynamics?

2013 ◽  
Vol 58 (6) ◽  
pp. 1221-1233 ◽  
Author(s):  
Raquel Jiménez-Melero ◽  
José M. Ramírez ◽  
Francisco Guerrero
Keyword(s):  
Growth Rate ◽  
Population Dynamics ◽  
Seasonal Variation ◽  
Population Growth ◽  
Population Growth Rate

SOME MICRO-ECOLOGICAL FACTORS INFLUENCING THE POPULATION DYNAMICS OF SCHISTOSOMIASIS INTERMEDIATE HOST SNAILS IN KHARTOUM STATE, SUDA

2016 ◽  
Vol 4 (8) ◽  
pp. 147-151
Author(s):  
A. Zakaria Mohamed ◽  
Azzam Afifi ◽  
Yassir Sulieman ◽  
Theerakamol Pengsakul
Keyword(s):  
Growth Rate ◽  
Population Dynamics ◽  
Population Growth ◽  
Intermediate Host ◽  
Population Growth Rate ◽  
Ecological Factors ◽  
Water Bodies ◽  
Snail Population ◽  
Factors Influencing ◽  
High Turbidity

This study was conducted to determine the role of some micro-ecological factors influencing the population dynamics of schistosomiasis intermediate host snails in the water bodies of Khartoum State, Sudan. The results show that the air and water temperature play a significant role in the determination of snail growth, a gradual increase of air and water temperate causing an increase in the snail population growth rate with the peak in summer. Water of high turbidity and high current speed caused a drop in the snail population. Vegetation cover in water bodies showed a significant effect on the snail population, the denser the cover the higher the snail population growth rate.

scholarly journals The Use of Intraallelic Variability for Testing Neutrality and Estimating Population Growth Rate

Genetics ◽  
2001 ◽  
Vol 158 (2) ◽  
pp. 865-874 ◽  
Author(s):  
Montgomery Slatkin ◽  
Giorgio Bertorelle
Keyword(s):  
Growth Rate ◽  
Population Growth ◽  
Joint Distribution ◽  
Population Growth Rate ◽  
Marker Locus ◽  
European Population ◽  
Published Data ◽  
Data Sets ◽  
Marker Loci ◽  
Heterozygous Carriers

Abstract To better understand the forces affecting individual alleles, we introduce a method for finding the joint distribution of the frequency of a neutral allele and the extent of variability at closely linked marker loci (the intraallelic variability). We model three types of intraallelic variability: (a) the number of nonrecombinants at a linked biallelic marker locus, (b) the length of a conserved haplotype, and (c) the number of mutations at a linked marker locus. If the population growth rate is known, the joint distribution provides the basis for a test of neutrality by testing whether the observed level of intraallelic variability is consistent with the observed allele frequency. If the population growth rate is unknown but neutrality can be assumed, the joint distribution provides the likelihood of the growth rate and leads to a maximum-likelihood estimate. We apply the method to data from published data sets for four loci in humans. We conclude that the Δ32 allele at CCR5 and a disease-associated allele at MLH1 arose recently and have been subject to strong selection. Alleles at PAH appear to be neutral and we estimate the recent growth rate of the European population to be ∼0.027 per generation with a support interval of (0.017-0.037). Four of the relatively common alleles at CFTR also appear to be neutral but ΔF508 appears to be significantly advantageous to heterozygous carriers.

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