scholarly journals Species with more volatile population dynamics are differentially impacted by weather

2015 ◽  
Vol 11 (2) ◽  
pp. 20140792 ◽  
Author(s):  
Joshua G. Harrison ◽  
Arthur M. Shapiro ◽  
Anne E. Espeset ◽  
Christopher C. Nice ◽  
Joshua P. Jahner ◽  
...  

Climatic variation has been invoked as an explanation of population dynamics for a variety of taxa. Much work investigating the link between climatic forcings and population fluctuation uses single-taxon case studies. Here, we conduct comparative analyses of a multi-decadal dataset describing population dynamics of 50 co-occurring butterfly species at 10 sites in Northern California. Specifically, we explore the potential commonality of response to weather among species that encompass a gradient of population dynamics via a hierarchical Bayesian modelling framework. Results of this analysis demonstrate that certain weather conditions impact volatile, or irruptive, species differently as compared with relatively stable species. Notably, precipitation-related variables, including indices of the El Niño Southern Oscillation, have a more pronounced impact on the most volatile species. We hypothesize that these variables influence vegetation resource availability, and thus indirectly influence population dynamics of volatile taxa. As one of the first studies to show a common influence of weather among taxa with similar population dynamics, the results presented here suggest new lines of research in the field of biotic–abiotic interactions.

2017 ◽  
Vol 4 (7) ◽  
pp. 170190 ◽  
Author(s):  
Nicholas A. Pardikes ◽  
Joshua G. Harrison ◽  
Arthur M. Shapiro ◽  
Matthew L. Forister

A long-standing challenge for population biology has been to understand why some species are characterized by populations that fluctuate in size independently, while populations of other species fluctuate synchronously across space. The effects of climatic variation and dispersal have been invoked to explain synchronous population dynamics, however an understanding of the relative influence of these drivers in natural populations is lacking. Here we compare support for dispersal- versus climate-driven models of interspecific variation in synchrony using 27 years of observations of 65 butterfly species at 10 sites spanning 2750 m of elevation in Northern California. The degree of spatial synchrony exhibited by each butterfly species was used as a response in a unique approach that allowed us to investigate whether interspecific variation in response to climate or dispersal propensity was most predictive of interspecific variation in synchrony. We report that variation in sensitivity to climate explained 50% of interspecific variation in synchrony, whereas variation in dispersal propensity explained 23%. Sensitivity to the El Niño Southern Oscillation, a primary driver of regional climate, was the best predictor of synchrony. Combining sensitivity to climate and dispersal propensity into a single model did not greatly increase model performance, confirming the primacy of climatic sensitivity for driving spatial synchrony in butterflies. Finally, we uncovered a relationship between spatial synchrony and population decline that is consistent with theory, but small in magnitude, which suggests that the degree to which populations fluctuate in synchrony is of limited use for understanding the ongoing decline of the Northern California butterfly fauna.


2021 ◽  
Vol 35 ◽  
pp. 00023
Author(s):  
Nikolay Vinokurov

The work provides data on the dynamics of the abundance of 205 taxa from 19 genera: Cleptes, Colpopyga, Elampus, Omalus, Philoctetes, Pseudomalus, Hedychridium, Hedychrum, Holopyga, Chrysidea, Chrysis, Euchroeus, Chrysura, Pseudochrysis, Spinolia, Spinolia, including species rare and new for the fauna of the North Caucasus and Russia. By the nature of the population dynamics, five groups of cuckoo wasps were identified: spring – represented by 7 species from 4 genera; spring-summer – 76 species from 10 genera; summer – 113 species from 16 genera; summer-autumn – 4 species from 2 genera and spring-summer-autumn – 5 species from 3 genus. According to the duration of flight, eurychronous species of cuckoo wasps were identified, which are found throughout the season from spring to autumn; mesochronous – the years of which affect the end of May and summer months and stenochronous – confined to a short period of time. Eurychronic accounted for 2.4%, mesochronous 24.9%, stenochronic 72.7%. The number of generations of cuckoo wasps is related to the dynamics of the number of the host. In the mountains, the peaks of activity shift towards the middle of summer, most species have one peak of activity; due to the frequent changes in weather conditions in the mountains, the phenological characteristics of the cuckoo wasps and their hosts do not coincide in terms with the lowland populations and the periods of activity can be extended in time. Phenological characteristics of rare and new species for the fauna of the North Caucasus and Russia are presented for the first time. The data obtained expand the understanding of the biodiversity and dynamics of the abundance of cuckoo wasps in the North Caucasus and can be used for environmental protection measures and rational nature management in the south of Russia.


PLoS ONE ◽  
2020 ◽  
Vol 15 (12) ◽  
pp. e0243794
Author(s):  
Sam McKechnie ◽  
David Fletcher ◽  
Jamie Newman ◽  
Corey Bragg ◽  
Peter W. Dillingham ◽  
...  

A suite of factors may have contributed to declines in the tītī (sooty shearwater; Ardenna grisea) population in the New Zealand region since at least the 1960s. Recent estimation of the magnitude of most sources of non-natural mortality has presented the opportunity to quantitatively assess the relative importance of these factors. We fit a range of population dynamics models to a time-series of relative abundance data from 1976 until 2005, with the various sources of mortality being modelled at the appropriate part of the life-cycle. We present estimates of effects obtained from the best-fitting model and using model averaging. The best-fitting models explained much of the variation in the abundance index when survival and fecundity were linked to the Southern Oscillation Index, with strong decreases in adult survival, juvenile survival and fecundity being related to El Niño-Southern Oscillation (ENSO) events. Predation by introduced animals, harvesting by humans, and bycatch in fisheries also appear to have contributed to the population decline. It is envisioned that the best-fitting models will form the basis for quantitative assessments of competing management strategies. Our analysis suggests that sustainability of the New Zealand tītī population will be most influenced by climate, in particular by how climate change will affect the frequency and intensity of ENSO events in the future. Removal of the effects of both depredation by introduced predators and harvesting by humans is likely to have fewer benefits for the population than alleviating climate effects.


Oecologia ◽  
2008 ◽  
Vol 157 (4) ◽  
pp. 583-592 ◽  
Author(s):  
Jessica J. Hellmann ◽  
Shannon L. Pelini ◽  
Kirsten M. Prior ◽  
Jason D. K. Dzurisin

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Patrick Giraudoux ◽  
Petra Villette ◽  
Jean-Pierre Quéré ◽  
Jean-Pierre Damange ◽  
Pierre Delattre

Abstract Rodent outbreaks have plagued European agriculture for centuries, but continue to elude comprehensive explanation. Modelling and empirical work in some cyclic rodent systems suggests that changes in reproductive parameters are partly responsible for observed population dynamics. Using a 17-year time series of Microtus arvalis population abundance and demographic data, we explored the relationship between meteorological conditions (temperature and rainfall), female reproductive activity, and population growth rates in a non-cyclic population of this grassland vole species. We found strong but complex relationships between female reproduction and climate variables, with spring female reproduction depressed after cold winters. Population growth rates were, however, uncorrelated with either weather conditions (current and up to three months prior) or with female reproduction (number of foetuses per female and/or proportion of females reproductively active in the population). These results, coupled with age-structure data, suggest that mortality, via predation, disease, or a combination of the two, are responsible for the large multi-annual but non-cyclic population dynamics observed in this population of the common vole.


Oecologia ◽  
2021 ◽  
Author(s):  
Melanie Nägeli ◽  
Patrick Scherler ◽  
Stephanie Witczak ◽  
Benedetta Catitti ◽  
Adrian Aebischer ◽  
...  

AbstractThe joint effects of interacting environmental factors on key demographic parameters can exacerbate or mitigate the separate factors’ effects on population dynamics. Given ongoing changes in climate and land use, assessing interactions between weather and food availability on reproductive performance is crucial to understand and forecast population dynamics. By conducting a feeding experiment in 4 years with different weather conditions, we were able to disentangle the effects of weather, food availability and their interactions on reproductive parameters in an expanding population of the red kite (Milvus milvus), a conservation-relevant raptor known to be supported by anthropogenic feeding. Brood loss occurred mainly during the incubation phase, and was associated with rainfall and low food availability. In contrast, brood loss during the nestling phase occurred mostly due to low temperatures. Survival of last-hatched nestlings and nestling development was enhanced by food supplementation and reduced by adverse weather conditions. However, we found no support for interactive effects of weather and food availability, suggesting that these factors affect reproduction of red kites additively. The results not only suggest that food-weather interactions are prevented by parental life-history trade-offs, but that food availability and weather conditions are crucial separate determinants of reproductive output, and thus population productivity. Overall, our results suggest that the observed increase in spring temperatures and enhanced anthropogenic food resources have contributed to the elevational expansion and the growth of the study population during the last decades.


Author(s):  
Sandhya Patidar ◽  
Eleanor Tanner ◽  
Bankaru-Swamy Soundharajan ◽  
Bhaskar Sen Gupta

Water is essential to all life-forms including various ecological, geological, hydrological, and climatic processes/activities. With changing climate, associated El Nino/Southern Oscillation (ENSO) events appear to stimulate highly uncertain patterns of precipitation (P) and evapotranspiration (EV) processes across the globe. Changes in P and EV patterns are highly sensitive to temperature variation and thus also affecting natural streamflow processes. This paper presents a novel suite of stochastic modelling approaches for associating streamflow sequences with climatic trends. The present work is built upon a stochastic modelling framework HMM_GP that integrates a Hidden Markov Model with a Generalised Pareto distribution for simulating synthetic flow sequences. The GP distribution within HMM_GP model is aimed to improve the model's efficiency in effectively simulating extreme events. This paper further investigated the potentials of Generalised Extreme Value Distribution (EVD) coupled with an HMM model within a regression-based scheme for associating impacts of precipitation and evapotranspiration processes on streamflow. The statistical characteristic of the pioneering modelling schematic has been thoroughly assessed for their suitability to generate/predict synthetic river flows sequences for a set of future climatic projections. The new modelling schematic can be adapted for a range of applications in the area of hydrology, agriculture and climate change.


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