scholarly journals Early snowmelt projected to cause population decline in a subalpine plant

2019 ◽  
Vol 116 (26) ◽  
pp. 12901-12906 ◽  
Author(s):  
Diane R. Campbell
Keyword(s):  
Climate Change ◽  
Population Growth ◽  
Seed Production ◽  
Demographic Data ◽  
Population Decline ◽  
Floral Display ◽  
Vital Rates ◽  
Flower Number ◽  
Early Snowmelt ◽  
The Impact

How climate change influences the dynamics of plant populations is not well understood, as few plant studies have measured responses of vital rates to climatic variables and modeled the impact on population growth. The present study used 25 y of demographic data to analyze how survival, growth, and fecundity respond to date of spring snowmelt for a subalpine plant. Fecundity was estimated by seed production (over 15 y) and also divided into flower number, fruit set, seeds per fruit, and escape from seed predation. Despite no apparent effects on flower number, plants produced more seeds in years with later snowmelt. Survival and probability of flowering were reduced by early snowmelt in the previous year. Based on demographic models, earlier snowmelt with warming is expected to lead to negative population growth, driven especially by changes in seedling establishment and seed production. These results provide a rare example of how climate change is expected to influence the dynamics of a plant population. They furthermore illustrate the potential for strong population impacts even in the absence of more commonly reported visual signs, such as earlier blooming or reduced floral display in early melting years.

scholarly journals Climate change, snow mold and the Bromus tectorum invasion: mixed evidence for release from cold weather pathogens

AoB Plants ◽  
2019 ◽  
Vol 11 (5) ◽  
Author(s):  
Danielle M Smull ◽  
Nicole Pendleton ◽  
Andrew R Kleinhesselink ◽  
Peter B Adler
Keyword(s):  
Climate Change ◽  
Population Growth ◽  
Seed Production ◽  
Plant Pathogens ◽  
Field Experiments ◽  
Bromus Tectorum ◽  
Cold Weather ◽  
Fungal Treatment ◽  
Snow Mold ◽  
Early Snowmelt

Abstract Climate change is reducing the depth and duration of winter snowpack, leading to dramatic changes in the soil environment with potentially important ecological consequences. Previous experiments in the Intermountain West of North America indicated that loss of snowpack increases survival and population growth rates of the invasive annual grass Bromus tectorum; however, the underlying mechanism is unknown. We hypothesized that reduced snowpack might promote B. tectorum population growth by decreasing damage from snow molds, a group of subnivean fungal pathogens. To test this hypothesis, we conducted greenhouse and field experiments to investigate the interaction between early snowmelt and either fungicide addition or snow mold infection of B. tectorum. The greenhouse experiment confirmed that the snow mold Microdochium nivale can cause mortality of B. tectorum seedlings. In the field experiment, early snowmelt and fungicide application both increased B. tectorum survival, but their effects did not interact, and snow mold inoculation had no effect on survival. We did find interactive effects of snowmelt and fungal treatments on B. tectorum seed production: with ambient snowpack, M. nivale inoculation reduced seed production and fungicide increased it, whereas in the early snowmelt treatment seed production was high regardless of fungal treatment. However, treatment effects on seed production did not translate directly to overall population growth, which did not respond to the snow melt by fungal treatment interaction. Based on our mixed results, the hypothesis that reduced snowpack may increase B. tectorum fitness by limiting the effects of plant pathogens deserves further investigation.

scholarly journals The impact of population growth and climate change on food security in Africa: looking ahead to 2050

2017 ◽  
Vol 15 (2) ◽  
pp. 124-135 ◽  
Author(s):  
C. Hall ◽  
T. P. Dawson ◽  
J. I. Macdiarmid ◽  
R.B. Matthews ◽  
P. Smith
Keyword(s):  
Climate Change ◽  
Food Security ◽  
Population Growth ◽  
The Impact

scholarly journals Market Access and the Concentration of Economic Activity in a System of Declining Cities

REGION ◽  
2018 ◽  
Vol 5 (3) ◽  
pp. 97-109
Author(s):  
Luis Eduardo Quintero ◽  
Paula Restrepo
Keyword(s):  
Population Growth ◽  
Market Access ◽  
Population Decline ◽  
Market Potential ◽  
Population Loss ◽  
City Population ◽  
Alternative Measures ◽  
System Of Cities ◽  
The Impact ◽  
The City

Market access has been widely used as a measure of agglomeration spillovers in models that seek to explain productivity, economic or population growth at the city level. Most results have shown that having higher market access is beneficial to these outcomes. These results, both theoretical and empirical, have been obtained in a context of population growth. This article examines the impact that market access has on a system of cities that has suffered a negative population shock. An extended version of the Brezis and Krugman (1997) model of life cycle of cities predicts that a system of cities experiencing population loss will see a relative reorganization of its population from small to larger cities, and that higher market potential will make this movement stronger. We test these predictions with a comprehensive sample of cities in Eastern Europe and Central Asia. We find that having higher market access - when operating in an environment of population decline - is detrimental to city population growth. This result is robust to different measures of market access that use population. Alternative measures that use economic size rather population are tested, and the result weaker. A possible explanation is that using NLs restricts the sample to only using larger cities. 

A multiproxy reconstruction of vegetation dynamics in the Eastern Alps (Switzerland): combining paleoecological and paleogenetic approaches.

2021 ◽  
Author(s):  
Laura Dziomber ◽  
Lisa Gurtner ◽  
Maria Leunda ◽  
Christoph Schwörer
Keyword(s):  
Climate Change ◽  
Ancient Dna ◽  
Vegetation Dynamics ◽  
Population Decline ◽  
Future Climate ◽  
Ice Age ◽  
Future Climate Change ◽  
The Holocene ◽  
Plant Remains ◽  
The Impact

<p>Current and future climate change is a serious threat to biodiversity and ecosystem stability. With a rapid increase of global temperatures by 1.5°C since the pre-industrial period and a projected warming of 1.5-4°C by the end of this century, plant species are forced to either adapt to these changes, shift their distribution range to higher elevation, or face population decline and extinction. Today, there is an urgent need to better understand the responses of mountain vegetation to climate change in order to predict the consequences of the human-driven global change currently occurring during the Anthropocene and maintain species diversity and ecosystem services. However, most predictions are based on short-term experiments. There is, in general, an insufficient use of longer time scales in conservation biology to understand long-term processes. Palaeoecological data are a great source of information to infer past species responses to changing environmental factors, such as climate or anthropogenic disturbances.</p><p>The last climate change of a similar magnitude and rate as projected for this century was the transition between the last Ice Age and the Holocene interglacial (ca. 11,700 years ago). By analyzing subfossil plant remains such as plant macrofossils, charcoal and pollen from natural archives, we can study past responses to climate change. However, until recently it was not possible to reconstruct changes at the population level. With the development of new methods to extract ancient DNA (aDNA) from plant remains and next generation DNA-sequencing techniques, we can now infer past population dynamics by analyzing the genetic variation through time. Ancient DNA might also be able to reveal if species could adapt to climatic changes by identifying intraspecific variation of specific genes related to climatic adaptations.</p><p>We are currently investigating a palaeoecological archive from a high-altitude mountain lake, Lai da Vons (1991 m a.s.l), situated in Eastern Switzerland. We are presenting preliminary macrofossil, pollen and charcoal results to reconstruct local to regional vegetation and fire dynamics with high chronological precision and resolution. In a next step, we will use novel molecular methods, in order to track adaptive and neutral genetic diversity through the Holocene by analyzing aDNA from subfossil conifer needles. The overarching goal of this large-scale, multiproxy study is to better understand past vegetation dynamics and the impact of future climate change on plants at multiple scales; from the genetic to the community level.</p><p> </p>

Using population dynamics modelling to evaluate potential success of restoration: a case study of a Hawaiian vine in a changing climate

2014 ◽  
Vol 42 (1) ◽  
pp. 20-30 ◽  
Author(s):  
TAMARA M. WONG ◽  
TAMARA TICKTIN
Keyword(s):  
Population Growth ◽  
Growth Rates ◽  
Key Management ◽  
Demographic Data ◽  
Population Decline ◽  
Management Strategies ◽  
Survival Rates ◽  
Population Modelling ◽  
Population Growth Rates

SUMMARYDemographic comparisons between wild and restored populations of at-risk plant species can reveal key management strategies for effective conservation, but few such studies exist. This paper evaluates the potential restoration success ofAlyxia stellata, a Hawaiian vine. Stage-structured matrix projection models that compared long-term and transient dynamics of wild versus restoredA. stellatapopulations, and restored populations under different levels of canopy cover, were built from demographic data collected over a four year period. Stochastic models of wild populations projected stable or slightly declining long-term growth rates depending on frequency of dry years. Projected long-term population growth rates of restored populations were significantly higher in closed than open canopy conditions, but indicated population decline under both conditions. Life table response experiments illustrated that lower survival rates, especially of small adults and juveniles, contributed to diminished population growth rates in restored populations. Transient analyses for restored populations projected short-term decline occurring even faster than predicted by asymptotic dynamics. Restored populations will not be viable over the long term under conditions commonly found in restoration projects and interventions will likely be necessary. This study illustrates how the combination of long-term population modelling and transient analyses can be effective in providing relevant information for plant demographers and restoration practitioners to promote self-sustaining native populations, including under future climates.

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.

Cardinal Numbers: Changing Patterns of Malaria and Mortality in Rome, 494–1850

2018 ◽  
Vol 49 (3) ◽  
pp. 397-417 ◽  
Author(s):  
Benjamin Reilly
Keyword(s):  
Climate Change ◽  
Population Growth ◽  
Demographic Data ◽  
Cardinal Numbers ◽  
Changing Patterns

The use of demographic data about cardinal mortality drawn from Salvador Miranda’s “Cardinals of the Holy Roman Church” archive confirms and quantifies the greater vulnerability of northern Europeans to Rome’s malarial fevers relative to their Roman counterparts. Non-Italian visitors to Rome suffered about three times the rate of malaria deaths as did Italians and Greeks, who had acquired various defenses against malaria. Northern Italians were far less susceptible than expected to Rome’s malarial fevers, however, whereas Iberian visitors to Rome were far more so. The eventual decline of malaria in Rome was not so much a function of climate change as of Rome’s steady post-1600 population growth.

scholarly journals Projecting Suitability and Climate Vulnerability of Bhutanitis thaidina (Blanchard) (Lepidoptera: Papilionidae) with Conservation Implications

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Shao-Ji Hu ◽  
Dong-Hui Xing ◽  
Zhi-Xian Gong ◽  
Jin-Ming Hu
Keyword(s):  
Climate Change ◽  
Habitat Fragmentation ◽  
Species Distribution Model ◽  
Population Decline ◽  
Future Climate ◽  
Food Plants ◽  
Distribution Model ◽  
The Impact ◽  
Northwestern Yunnan ◽  
Northeastern Yunnan

Abstract Bhutanitis thaidina is an endemic, rare, and protected swallowtail in China. Deforestation, habitat fragmentation, illegal commercialised capture, and exploitation of larval food plants are believed to be the four major causes of population decline of B. thaidina in the recent decade. However, little attention was paid to the impact of climate change. This study used ecological niche factor analysis and species distribution model to analyse the current suitable areas for B. thaidina with BioClim variables as well as its future suitable areas under four future climate scenarios (represented by four Representative Concentration Pathways: RCP2.6, RCP4.5, RCP6.0, and RCP8.5). Statistical analysis was carried out to compare the possible area and altitude changes to the distribution of B. thaidina under changing climate. Our analyses showed that the suitable areas for B. thaidina are fragmented under the current climate, with four suitable centres in northwestern Yunnan, northeastern Yunnan and northwestern Guizhou, the western margin of Sichuan Basin, and Qinling mountains. Apart from further habitat fragmentation under climate change, slight range expansion (average 6.0–8.9%) was detected under the RCP2.6 and RCP4.5 scenarios, while more range contraction (average 1.3–26.9%) was detected under the RCP6.0 and RCP8.5 scenarios, with the two southern suitable centres suffering most. Also, a tendency of contraction (2,500–3,500 m) and upslope shift (~600 m) in suitable altitude range were detected. The findings of this study supported the climate-vulnerable hypothesis of B. thaidina, especially under future climate like the RCP6.0 and RCP8.5 scenarios, in terms of contraction in suitable areas and altitude ranges. Conservation priority should be given to northwestern Yunnan, northeastern Yunnan, and northwestern Guizhou to alleviate the stress of massive habitat loss and extinction. Refugial areas should be established in all four suitable centres to maintain genetic diversity of B. thaidina in China.

The impact of temperature on population and community dynamics

2020 ◽  
pp. 243-262
Author(s):  
David A. Vasseur
Keyword(s):  
Climate Change ◽  
Carrying Capacity ◽  
Environmental Variables ◽  
Community Dynamics ◽  
Thermal Sensitivity ◽  
Theoretical Work ◽  
Vital Rates ◽  
Change Temperature ◽  
Population And Community Dynamics ◽  
The Impact

Of the myriad of environmental variables that are currently in flux due to anthropogenic climate change, temperature is one of the most ubiquitous and well-studied. Temperature directly influences the vital rates and ecological thresholds that determine how quickly populations grow or decline and many studies have sought to determine how these influences culminate at the population and community level. This chapter surveys the theoretical work in this area and details how our growing understanding of the relationships between temperature and vital rates and thresholds has led to new insights and challenges. The latter sections of the chapter reveal a key principle to guide the ongoing debate about the temperature-dependence of a key parameter underlying nearly all population and community models: the carrying capacity. From this, a simple model is used to demonstrate how linkages between the thermal sensitivity of population growth and carrying capacity determine dynamics and the propensity for extinction in warming environments.

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