scholarly journals Geographical variation in the spatial synchrony of a forest-defoliating insect: isolation of environmental and spatial drivers

2013 ◽  
Vol 280 (1753) ◽  
pp. 20122373 ◽  
Author(s):  
Kyle J. Haynes ◽  
Ottar N. Bjørnstad ◽  
Andrew J. Allstadt ◽  
Andrew M. Liebhold
Keyword(s):  
Gypsy Moth ◽  
Forest Type ◽  
Weather Conditions ◽  
Spatial Proximity ◽  
Generalist Predators ◽  
Population Fluctuations ◽  
Spatial Synchrony ◽  
Acorn Production ◽  
Environmental Perturbations ◽  
Underlying Mechanisms

Despite the pervasiveness of spatial synchrony of population fluctuations in virtually every taxon, it remains difficult to disentangle its underlying mechanisms, such as environmental perturbations and dispersal. We used multiple regression of distance matrices (MRMs) to statistically partition the importance of several factors potentially synchronizing the dynamics of the gypsy moth, an invasive species in North America, exhibiting outbreaks that are partially synchronized over long distances (approx. 900 km). The factors considered in the MRM were synchrony in weather conditions, spatial proximity and forest-type similarity. We found that the most likely driver of outbreak synchrony is synchronous precipitation. Proximity played no apparent role in influencing outbreak synchrony after accounting for precipitation, suggesting dispersal does not drive outbreak synchrony. Because a previous modelling study indicated weather might indirectly synchronize outbreaks through synchronization of oak masting and generalist predators that feed upon acorns, we also examined the influence of weather and proximity on synchrony of acorn production. As we found for outbreak synchrony, synchrony in oak masting increased with synchrony in precipitation, though it also increased with proximity. We conclude that precipitation could synchronize gypsy moth populations directly, as in a Moran effect, or indirectly, through effects on oak masting, generalist predators or diseases.

Predator release from invertebrate generalists does not explain geometrid moth (Lepidoptera: Geometridae) outbreaks at high altitudes

2013 ◽  
Vol 145 (2) ◽  
pp. 184-192 ◽  
Author(s):  
Tino Schott ◽  
Lauri Kapari ◽  
Snorre B. Hagen ◽  
Ole Petter L. Vindstad ◽  
Jane U. Jepsen ◽  
...  
Keyword(s):  
Carabid Beetles ◽  
Birch Forest ◽  
Generalist Predators ◽  
Tree Line ◽  
High Altitudes ◽  
Lower Altitude ◽  
Rove Beetles ◽  
Northern Norway ◽  
Winter Moth ◽  
Underlying Mechanisms

AbstractOutbreaks of geometrid defoliators in subarctic birch forest in Fennoscandia often occur at high altitude in a distinct zone along the tree line. At the same time, moth larvae may not have an impact on the forest at lower altitude. Directly adjacent outbreak and nonoutbreak areas offer unique opportunities for studying the underlying mechanisms of outbreaks. Within two altitudinal gradients in coastal northern Norway, we investigated whether altitudinal outbreaks might be caused by release from pupal predation by ground-dwelling invertebrates such as harvestmen (Opiliones), spiders (Araneae), rove beetles (Coleoptera: Staphylinidae), carabid beetles (Coleoptera: Carabidae), and other beetles (Coleoptera). We predicted a consistently higher abundance of such generalist predators at low versus high altitudes. Our results did not support this prediction. There was no consistent altitudinal variation in the abundance of predators that could be related to zonal moth outbreaks in the birch forest slopes. In addition, none of the predator groups investigated showed any numerical response to a distinct outbreak of winter moth that took place during the course of the study. Consequently, localised moth outbreaks at the altitudinal tree line in northern Norway cannot be explained by the release from pupal predation by the predator groups examined here.

scholarly journals Environmental perturbations influence telomere dynamics in long-lived birds in their natural habitat

2013 ◽  
Vol 9 (5) ◽  
pp. 20130511 ◽  
Author(s):  
Yuichi Mizutani ◽  
Naoki Tomita ◽  
Yasuaki Niizuma ◽  
Ken Yoda
Keyword(s):  
Natural Habitat ◽  
Weather Conditions ◽  
Rate Of Change ◽  
Natural Setting ◽  
Stress Exposure ◽  
Free Living ◽  
Rates Of Change ◽  
Environmental Perturbations ◽  
Cellular Ageing ◽  
Telomere Dynamics

Telomeres are regarded as markers of biological or cellular ageing because they shorten with the degree of stress exposure. Accordingly, telomere lengths should show different rates of change when animals are faced with different intensities of environmental challenges. However, a relationship between telomere length and the environment has not yet been tested within a natural setting. Here, we report longitudinal telomere dynamics in free-living, black-tailed gulls ( Larus crassirostris ) through the recapture of birds of a known age over 2–5 consecutive years. The rate of change in telomere lengths differed with respect to year but not sex or age. The years when gulls showed stable telomere lengths or increases in telomere lengths (from 2009 to 2010) and decreases in telomere lengths (from 2010 to 2011) were characterized by El Niño and the Great Japan Earthquake, respectively. Both events are suspected to have had long-lasting effects on food availability and/or weather conditions. Thus, our findings that telomere dynamics in long-lived birds are influenced by dramatic changes in environmental conditions highlight the importance of environmental fluctuations in affecting stress and lifespan.

Forest Type Affects Predation on Gypsy Moth (Lepidoptera: Lymantriidae) Pupae in Japan

1998 ◽  
Vol 27 (4) ◽  
pp. 858-862 ◽  
Author(s):  
Andrew M. Liebhold ◽  
Yasutomo Higashiura ◽  
Akira Unno
Keyword(s):  
Gypsy Moth ◽  
Forest Type

Synchrony in larval yellow perch abundance: the influence of the Moran Effect during early life history

2016 ◽  
Vol 73 (10) ◽  
pp. 1567-1574 ◽  
Author(s):  
Daniel J. Dembkowski ◽  
David W. Willis ◽  
Melissa R. Wuellner
Keyword(s):  
Yellow Perch ◽  
Spatial Scales ◽  
Population Characteristics ◽  
Freshwater Species ◽  
Population Fluctuations ◽  
Moran Effect ◽  
Spatial Synchrony ◽  
Geographic Scale ◽  
Data Set ◽  
Spatiotemporal Trends

Recruitment may vary substantially in fish populations, which can drive not only adult population characteristics but also the dynamics of fishes dependent on the species of interest and recreational fisheries for these species. However, spatiotemporal trends in population fluctuations and potential drivers of recruitment variability are poorly understood. Therefore, we used a long-term (2000–2014) data set to estimate the extent of spatial synchrony in larval abundance and factors influencing variability in recruitment of yellow perch (Perca flavescens). Contrary to the prevailing paradigm that spatial synchrony in population fluctuations (i.e., recruitment) is typically absent or occurs at small spatial scales (<50 km) for freshwater species, abundance of larval yellow perch was synchronous among spatially segregated systems across a geographic scale of at least 180 km. Additionally, variation in larval yellow perch density was influenced by spatially-correlated climatic and hydrological variables (indicative of the Moran Effect). Results ultimately broaden the scale at which factors were previously thought to influence recruitment of freshwater fishes and provide important insight to patterns and processes that structure yellow perch populations.

scholarly journals Causes and consequences of variation in early-life telomere length in a bird metapopulation

2021 ◽  
Author(s):  
Michael Le Pepke ◽  
Thomas Kvalnes ◽  
Peter Sjolte Ranke ◽  
Yimen G. Araya-Ajoy ◽  
Jonathan Wright ◽  
...  
Keyword(s):  
Reproductive Success ◽  
Population Density ◽  
Telomere Length ◽  
Environmental Conditions ◽  
Early Life ◽  
Morphological Traits ◽  
Weather Conditions ◽  
Population Fluctuations ◽  
Individual Quality ◽  
Pace Of Life

1.Environmental conditions during early-life development can have lasting effects on individual quality and fitness. Telomere length (TL) may correlate with early-life conditions and may be an important mediator or biomarker of individual quality or pace-of-life, as periods of increased energy demands can increase telomere attrition due to oxidative stress. Thus, knowledge of the mechanisms that generate variation in TL, and the relation between TL and fitness, is important in understanding the role of telomeres in ecology and life-history evolution. 2.Here, we investigate how environmental conditions and morphological traits are associated with early-life TL and if TL predicts natal dispersal probability or components of fitness in two populations of wild house sparrows (Passer domesticus). 3.We measured morphological traits and blood TL in 2746 nestlings from 20 cohorts (1994-2013) and retrieved data on weather conditions. We monitored population fluctuations, and individual survival and reproductive output using field observations and genetic pedigrees. We then used generalized linear mixed-effects models to test which factors affected TL in early-life, and if TL predicted dispersal propensity, or was associated with recruitment probability, mortality risk, or reproductive success.4.We found a negative effect of population density on TL, but only in one of the populations. There was a curvilinear association between TL and the maximum daily North Atlantic Oscillation (NAO) index during incubation, suggesting that there are optimal weather conditions that result in the longest TL. Dispersers tended to have shorter telomeres than non-dispersers. TL did not predict survival, but we found a tendency for individuals with short telomeres to have higher annual reproductive success.5.Our study showed how early-life TL is shaped by effects of growth, weather conditions and population density, supporting that environmental stressors negatively affect TL in wild populations. In addition, TL may be a mediator or biomarker of individual pace-of-life, with higher dispersal rates and annual reproduction tending to be associated with shorter early-life TL in this study. However, clear associations between early-life TL and individual fitness seems difficult to establish and may differ between different populations in the wild.

scholarly journals Harvesting can stabilize population fluctuations and buffer the impacts of climate change

2021 ◽  
Author(s):  
Bart Peeters ◽  
Vidar GrØtan ◽  
Marlène Gamelon ◽  
Vebjørn Veiberg ◽  
Aline Magdalena Lee ◽  
...  
Keyword(s):  
Life Histories ◽  
Resource Competition ◽  
Extinction Risk ◽  
Population Models ◽  
Environmental Stochasticity ◽  
Environmental Drivers ◽  
Population Fluctuations ◽  
Vital Rates ◽  
Density Dependent ◽  
Environmental Perturbations

Harvesting can magnify the destabilizing effects of environmental perturbations on population dynamics and, thereby, increase extinction risk. However, population-dynamic theory predicts that impacts of harvesting depend on the type and strength of density-dependent regulation. Here, we used population models for a range of life histories and an empirical reindeer case study to show that harvesting can actually buffer populations against environmental perturbations. This occurs because of density-dependent environmental stochasticity, where negative environmental impacts on vital rates are amplified at high population density due to intra-specific resource competition. Simulations from our population models show that even low levels of proportional harvesting may prevent overabundance, thereby dampening population fluctuations and reducing the risk of population collapse and quasi-extinction induced by environmental perturbations. Thus, depending on the species’ life history and the strength of density-dependent environmental drivers, harvesting can improve population resistance to increased climate variability and extreme weather expected under global warming.

Acorn production by oaks in central coastal California: influence of weather at three levels

1996 ◽  
Vol 26 (9) ◽  
pp. 1677-1683 ◽  
Author(s):  
Walter D. Koenig ◽  
Johannes M.H. Knops ◽  
William J. Carmen ◽  
Mark T. Stanback ◽  
Ronald L. Mumme
Keyword(s):  
Environmental Factors ◽  
Solar Radiation ◽  
Weather Conditions ◽  
Annual Rainfall ◽  
Acorn Production ◽  
Crop Size ◽  
A Site ◽  
Pollination And Fertilization

Mean annual acorn crop size of oaks in central coastal California correlated with weather for four of five species. For the deciduous Quercuslobata and Quercusdouglasii, larger crops were produced in years when April temperatures were warmest, while for the evergreen Quercusagrifalia and Quercuschrysolepis, crops were larger when there was more rain one and two years prior to the year when acorns were produced. No correlations were found between weather and mean annual acorn production by Quercuskelloggii. Within years, individual Q. douglasii that flowered during periods of greater solar radiation produced more acorns, and during 1 of 5 years individual Q. lobata and Q. agrifolia produced larger crops when they flowered during warm, dry periods. These results indicate that conditions favorable for pollination and fertilization strongly enhance mean annual acorn production in Q. lobata and Q. douglasii and may have an effect on differences in acorn crop size among individual Q. lobata, Q. douglasii, and Q. agrifolia. Mean annual acorn crops of these three species were significantly concordant among three sites in central coastal California 300 km apart. Weather conditions were also significantly correlated, especially annual rainfall and mean April temperatures. Thus, the environmental factors that have the strongest influence on mean annual acorn production within a site are also those that are the most geographically concordant. However, we found no relationship between environmental factors and differences in mean annual acorn production by these same three species at the three sites.

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