scholarly journals Evidence for the buffer effect operating in multiple species at a national scale

2015 ◽  
Vol 11 (1) ◽  
pp. 20140930 ◽  
Author(s):  
Martin J. P. Sullivan ◽  
Stuart E. Newson ◽  
James W. Pearce-Higgins
Keyword(s):  
Population Growth ◽  
Population Change ◽  
Spatial Scales ◽  
Bird Species ◽  
Buffer Effect ◽  
Breeding Bird ◽  
Population Growth Rates ◽  
National Monitoring ◽  
Multiple Species ◽  
The Uk

A long-standing aim of ecologists is to understand the processes involved in regulating populations. One such mechanism is the buffer effect, where lower quality habitats are increasingly used as a species reaches higher population densities, with a resultant average reduction in fecundity and survival limiting population growth. Although the buffer effect has been demonstrated in populations of a number of species, a test of its importance in influencing population growth rates of multiple species across large spatial scales is lacking. Here, we use habitat-specific population trends for 85 bird species from long-term national monitoring data (the UK Breeding Bird Survey) to examine its generality. We find that both patterns of population change and changes in habitat preference are consistent with the predictions of the buffer effect, providing support for its widespread operation.

Streamflow and Population Change in the Lower Salt River Valley of Central Arizona, ca. A.D. 775 to 1450

2008 ◽  
Vol 73 (1) ◽  
pp. 136-165 ◽  
Author(s):  
Scott E. Ingram
Keyword(s):  
Population Growth ◽  
Growth Rates ◽  
Population Change ◽  
River Valley ◽  
Channel Changes ◽  
Population Growth Rates ◽  
Salt River ◽  
Floods And Droughts ◽  
Salt River Valley ◽  
Irrigation Agriculture

Floods and droughts and their effects on Hohokam canal systems and irrigation agriculture play a prominent role in many cultural-historical interpretations of the Hohokam trajectory in the lower Salt River valley (modern-day Phoenix, Arizona metropolitan area). Catastrophic floods and associated geomorphic stream channel changes may have contributed to settlement and population changes and the substantial depopulation of the lower Salt River valley ca. A.D. 1450 or later. In this study, archaeological data on Hohokam domestic architecture is used to infer changes in prehistoric population growth rates from ca. A.D. 775 through 1450 in the most thoroughly documented canal system in the Salt River valley. Changes in growth rates are compared to the retrodictions of annual streamflow discharge volumes derived from tree-ring records. Contrary to expectations, population growth rates increased as the frequency, magnitude, and duration of inferred flooding, drought, and variability increased. These results challenge existing assumptions regarding the relationship among floods and droughts, conditions for irrigation agriculture, and population change in the lower Salt River valley.

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.

Hypotheses to explain patterns of population change among breeding bird species in England

2010 ◽  
Vol 143 (9) ◽  
pp. 2006-2019 ◽  
Author(s):  
Chris B. Thaxter ◽  
Andrew C. Joys ◽  
Richard D. Gregory ◽  
Stephen R. Baillie ◽  
David G. Noble
Keyword(s):  
Population Change ◽  
Bird Species ◽  
Breeding Bird

The dynamics and conservation of a spatially subdivided avian population in a fragmented landscape

2002 ◽  
Vol 8 (3) ◽  
pp. 159 ◽  
Author(s):  
Gary W. Luck
Keyword(s):  
Population Growth ◽  
Growth Rates ◽  
Agricultural Landscape ◽  
Local Population ◽  
Bird Species ◽  
Fragmented Landscape ◽  
Population Growth Rates ◽  
Local Populations ◽  
Subdivided Population ◽  
Subdivided Populations

Many bird species have declined in abundance in the agricultural regions of southern Australia, The mechanisms underlying these declines and the viability of the remaining populations are largely unknown, A number of species exist as spatially subdivided populations in heavily fragmented landscapes. Metapopulation and source-sink theory have influenced thinking on the dynamics of subdivided populations, but the general applicability of these theories is uncertain. I examined the dynamics of a subdivided population of the Rufous Treecreeper Climacteris ruta, a declining woodland passerine, occupying a fragmented, agricultural landscape in southwestern Australia. I determined if local populations could replace themselves without immigration and estimated population growth rates for the periods 1998-1999 and 1999-2000. I also examined the influence of movement between local populations on the viability of the entire subdivided population. Out of four geographically defined local populations, only one was above replacement, and only in one year of the study. Fledgling productivity and recruitment in the remainder were not sufficient to compensate for breeding female mortality. Long-term population growth estimates were <1 for all local populations, but variability in demographic rates suggested that the status of these populations may fluctuate over time. Also, there appeared to be sufficient movement between local populations, and into the study area from nearby habitat remnants, to slow or halt any decline in local population size, Within- and between-local-population processes appeared to be important to the viability of the treecreeper population during the two years of the study, and this is consistent with the general principles of metapopulation theory. I compared the dynamics of the treecreeper population occupying the fragmented landscape with one occupying a continuously wooded landscape and found that the latter had population growth rates >1, suggesting it may be an important population source and vital to the regional viability of the species.

scholarly journals Consistency counts: Modeling the effects of a change in protocol on Breeding Bird Survey counts

The Condor ◽  
2019 ◽  
Vol 121 (2) ◽  
Author(s):  
John R Sauer ◽  
William A Link ◽  
David J Ziolkowski ◽  
Keith L Pardieck ◽  
Daniel J Twedt
Keyword(s):  
Counting Process ◽  
Population Change ◽  
Southeastern United States ◽  
Bird Species ◽  
Breeding Bird Survey ◽  
Breeding Bird ◽  
Bird Survey ◽  
Primary Means ◽  
Time Distance ◽  
Log Linear

Abstract Analysis of North American Breeding Bird Survey (BBS) data requires controls for factors that influence detectability of birds along survey routes. Identifying factors that influence the counting process and incorporating them into analyses is a primary means of limiting bias in estimates of population change. Twedt (2015) implemented an alternative counting protocol on operational and nonrandom BBS survey routes in the southeastern United States. Observers on selected routes employed a time–distance protocol in which they recorded birds in 1-min intervals and in 2 distance categories. We hypothesized that processing and recording observations using this time–distance protocol could cause observers to count fewer birds relative to observers using the standard protocol. We used a hierarchical log-linear model with a categorical covariate associated with protocol (standard vs. time–distance) to assess whether use of the time–distance protocol had a measurable effect on counting birds along BBS routes. We applied this model to BBS data from portions of 8 states in which the time–distance protocol was implemented and estimated a protocol effect for 167 bird species. We documented a significant overall effect of the time–distance protocol on observers’ counts of birds. On average, the effect of the time–distance protocol was a 10% decline in counted birds; 80% of species had lower counts when the time–distance protocol was used on a survey route. However, because the time–distance protocol was only used on a small portion of the operational BBS routes and for a limited time, including the covariate for the time–distance protocol data had insignificant effects on analysis of population change. Although the covariate controlled for the effects of the time–distance protocol in BBS data, the results emphasize the importance of standardization as well as a need to track and, if necessary, control in analyses for changes in counting procedures along BBS routes.

scholarly journals The impact of human activity on anthropogenic dust emission over global semi-arid regions

2016 ◽  
Author(s):  
X. Guan ◽  
J. Huang ◽  
Y. Zhang ◽  
Y. Xie ◽  
J. Liu
Keyword(s):  
Population Growth ◽  
Growth Rates ◽  
Human Activities ◽  
Arid Regions ◽  
Population Change ◽  
Dust Emission ◽  
Dust Production ◽  
Population Growth Rates ◽  
The Impact ◽  
Semi Arid

Abstract. Anthropogenic dust is acknowledged as a product of human activities on disturbed soil, and is generated mainly from sensitive and fragile regions including croplands, pastures, and urbanized regions. In this study, we analyzed the behaviour of anthropogenic dust in semi-arid region of globe, and its relationship to human activities. An obvious peak in the total anthropogenic dust column, much higher magnitude than those of wet regions, was observed in semi-arid regions with population growth rates of more than 11.46 %. Four typical semi-arid regions, East China, India, North America and North Africa were selected to explore the local difference in anthropogenic dust production. The population growth rates in these areas were approximately 6.16 %, 17.71 %, 11.21 %, and 29.26 %, and the anthropogenic dust levels were 0.17 g m−2, 0.38 g m−2, 0.10 g m−2 and 0.21 g m−2, which are higher than the natural dust column burden. The anthropogenic dust column burden is positively correlated with the population and population change, indicating a contribution from human activities to the anthropogenic dust production. Based on the fact that anthropogenic dust can act as warming aerosol, the radiative effect of anthropogenic dust in semi-arid regions can not be ignored and requires further investigation.

scholarly journals Demographic drivers of decline and recovery in an Afro-Palaearctic migratory bird population

2016 ◽  
Vol 283 (1842) ◽  
pp. 20161387 ◽  
Author(s):  
Catriona A. Morrison ◽  
Robert A. Robinson ◽  
Simon J. Butler ◽  
Jacquie A. Clark ◽  
Jennifer A. Gill
Keyword(s):  
Population Growth ◽  
Survival Rates ◽  
Bird Species ◽  
Migratory Bird ◽  
Adult Survival ◽  
High Survival ◽  
Population Declines ◽  
High Productivity ◽  
Population Growth Rates ◽  
Sub Saharan

Across Europe, rapid population declines are ongoing in many Afro-Palaearctic migratory bird species, but the development of appropriate conservation actions across such large migratory ranges is severely constrained by lack of understanding of the demographic drivers of these declines. By constructing regional integrated population models (IPMs) for one of the suite of migratory species that is declining in the southeast of Britain but increasing in the northwest, we show that, while annual population growth rates in both regions vary with adult survival, the divergent regional trajectories are primarily a consequence of differences in productivity. Between 1994 and 2012, annual survival and productivity rates ranged over similar levels in both regions, but high productivity rates were rarer in the declining southeast population and never coincided with high survival rates. By contrast, population growth in the northwest was fuelled by several years in which higher productivity coincided with high survival rates. Simulated population trajectories suggest that realistic improvements in productivity could have reversed the decline (i.e. recovery of the population index to more than or equal to 1) in the southeast. Consequently, actions to improve productivity on European breeding grounds are likely to be a more fruitful and achievable means of reversing migrant declines than actions to improve survival on breeding, passage or sub-Saharan wintering grounds.

scholarly journals Life-history predicts global population responses to the weather in the terrestrial mammals

2021 ◽  
Author(s):  
John Jackson ◽  
Christie Le Coeur ◽  
Owen R Jones
Keyword(s):  
Life History ◽  
Population Growth ◽  
Growth Rates ◽  
Population Change ◽  
Absolute Magnitude ◽  
Effect Of Temperature ◽  
Population Growth Rates ◽  
Terrestrial Mammals ◽  
Climate Change Responses ◽  
Annual Population

AbstractWith the looming threat of abrupt ecological disruption due to a changing climate, predicting which species are most vulnerable to environmental change is critical. The life-history of a species is a promising candidate for explaining differences in climate-change responses, but we now need data linking population change, weather and life-history to explore these predictions. Here, we use long-term abundance records from 157 species of terrestrial mammals to investigate the link between weather and annual population growth rates. Overall, we found no consistent effect of temperature or precipitation anomalies on annual population growth rates, but there was variability in weather responses for populations within a species. Crucially, however, long-lived mammals with smaller litter sizes had responses with a reduced absolute magnitude compared to their shorter-living counterparts with larger litters. These results highlight the role of species-level life-history in driving responses to the environment.

Functional evenness of bird communities varies along the elevational gradient in Europe: Conservation implications

2019 ◽  
Author(s):  
Federico Morelli ◽  
Yanina
Keyword(s):  
Species Richness ◽  
Elevation Gradient ◽  
Bird Species ◽  
Elevational Gradient ◽  
Negative Association ◽  
Bird Communities ◽  
Breeding Bird ◽  
Bird Species Richness ◽  
Large Spatial Scale ◽  
Functional Evenness

ContextThe negative association between elevation and species richness is a well-recognized pattern in macro-ecology. ObjectivesThe aim of this study was to investigate changes in functional evenness of breeding bird communities along an elevation gradient in Europe. MethodsUsing the bird data from the EBCC Atlas of European Breeding Birds we estimated an index of functional evenness which can be assumed as a measure of the potential resilience of communities.ResultsOur findings confirm the existence of a negative association between elevation and bird species richness in all European eco regions. However, we also explored a novel aspect of this relationship, important for conservation: Our findings provide evidence at large spatial scale of a negative association between the functional evenness (potential community resilience) and elevation, independent of the eco region. We also found that the Natura2000 protected areas covers the territory most in need of protection, those characterized by bird communities with low potential resilience, in hilly and mountainous areas.ConclusionsThese results draw attention to European areas occupied by bird communities characterized by a potential lower capacity to respond to strong ecological changes, and, therefore, potentially more exposed to risks for conservation.

Sign in / Sign up

Export Citation Format

Share Document