scholarly journals Host and parasite thermal ecology jointly determine the effect of climate warming on epidemic dynamics

2018 ◽  
Vol 115 (4) ◽  
pp. 744-749 ◽  
Author(s):  
Alyssa-Lois M. Gehman ◽  
Richard J. Hall ◽  
James E. Byers
Keyword(s):  
Climate Change ◽  
Thermal Performance ◽  
Climate Warming ◽  
Thermal Adaptation ◽  
Parasite Prevalence ◽  
Life Cycles ◽  
Epidemic Dynamics ◽  
Northern Portion ◽  
Warming World ◽  
Host Parasite

Host–parasite systems have intricately coupled life cycles, but each interactor can respond differently to changes in environmental variables like temperature. Although vital to predicting how parasitism will respond to climate change, thermal responses of both host and parasite in key traits affecting infection dynamics have rarely been quantified. Through temperature-controlled experiments on an ectothermic host–parasite system, we demonstrate an offset in the thermal optima for survival of infected and uninfected hosts and parasite production. We combine experimentally derived thermal performance curves with field data on seasonal host abundance and parasite prevalence to parameterize an epidemiological model and forecast the dynamical responses to plausible future climate-warming scenarios. In warming scenarios within the coastal southeastern United States, the model predicts sharp declines in parasite prevalence, with local parasite extinction occurring with as little as 2 °C warming. The northern portion of the parasite’s current range could experience local increases in transmission, but assuming no thermal adaptation of the parasite, we find no evidence that the parasite will expand its range northward under warming. This work exemplifies that some host populations may experience reduced parasitism in a warming world and highlights the need to measure host and parasite thermal performance to predict infection responses to climate change.

scholarly journals Skewed temperature dependence affects range and abundance in a warming world

2018 ◽  
Author(s):  
Amy Hurford ◽  
Christina A. Cobbold ◽  
Péter K. Molnár
Keyword(s):  
Climate Change ◽  
Population Growth ◽  
Climate Warming ◽  
Synergistic Effects ◽  
Climate Change Impacts ◽  
Integrodifference Equation ◽  
Positive Effects ◽  
Growth Metrics ◽  
Fitness Curve ◽  
Warming World

AbstractPopulation growth metrics such asR0are usually asymmetric functions of temperature, with cold-skewed curves arising when the positive effects of a temperature increase outweigh the negative effects, and warm-skewed curves arising in the opposite case. Classically, cold-skewed curves are interpreted as more beneficial to a species under climate warming, because cold-skewness implies increased population growth over a larger proportion of the species’ fundamental thermal niche than warm-skewness. However, inference based on the shape of the fitness curve alone, and without considering the synergistic effects of net reproduction, density, and dispersal may yield an incomplete understanding of climate change impacts. We formulate a moving-habitat integrodifference equation model to evaluate how fitness curve skewness affects species’ range size and abundance during climate warming. In contrast to classic interpretations, we find that climate warming adversely affects populations with cold-skewed fitness curves, positively affects populations with warm-skewed curves and has relatively little or mixed effects on populations with symmetric curves. Our results highlight the synergistic effects of fitness curve skewness, spatially heterogeneous densities, and dispersal in climate change impact analyses, and that the common approach of mapping changes only inR0may be misleading.

scholarly journals Skewed temperature dependence affects range and abundance in a warming world

2019 ◽  
Vol 286 (1908) ◽  
pp. 20191157 ◽  
Author(s):  
Amy Hurford ◽  
Christina A. Cobbold ◽  
Péter K. Molnár
Keyword(s):  
Climate Change ◽  
Population Growth ◽  
Climate Warming ◽  
Synergistic Effects ◽  
Climate Change Impacts ◽  
Integrodifference Equation ◽  
Positive Effects ◽  
Growth Metrics ◽  
Fitness Curve ◽  
Warming World

Population growth metrics such as R 0 are usually asymmetric functions of temperature, with cold-skewed curves arising when the positive effects of a temperature increase outweigh the negative effects, and warm-skewed curves arising in the opposite case. Classically, cold-skewed curves are interpreted as more beneficial to a species under climate warming, because cold-skewness implies increased population growth over a larger proportion of the species's fundamental thermal niche than warm-skewness. However, inference based on the shape of the fitness curve alone, and without considering the synergistic effects of net reproduction, density and dispersal, may yield an incomplete understanding of climate change impacts. We formulate a moving-habitat integrodifference equation model to evaluate how fitness curve skewness affects species’ range size and abundance during climate warming. In contrast to classic interpretations, we find that climate warming adversely affects populations with cold-skewed fitness curves, positively affects populations with warm-skewed curves and has relatively little or mixed effects on populations with symmetric curves. Our results highlight the synergistic effects of fitness curve skewness, spatially heterogeneous densities and dispersal in climate change impact analyses, and that the common approach of mapping changes only in R 0 may be misleading.

scholarly journals Checklist of marine mammal parasites in New Zealand and Australian waters

2019 ◽  
Vol 93 (6) ◽  
pp. 649-676 ◽  
Author(s):  
K. Lehnert ◽  
R. Poulin ◽  
B. Presswell
Keyword(s):  
New Zealand ◽  
Marine Mammals ◽  
Anthropogenic Impacts ◽  
Parasite Prevalence ◽  
Emerging Diseases ◽  
Life Cycles ◽  
Parasitic Infections ◽  
Mammal Species ◽  
Top Predators ◽  
Host Parasite

AbstractMarine mammals are long-lived top predators with vagile lifestyles, which often inhabit remote environments. This is especially relevant in the oceanic waters around New Zealand and Australia where cetaceans and pinnipeds are considered as vulnerable and often endangered due to anthropogenic impacts on their habitat. Parasitism is ubiquitous in wildlife, and prevalence of parasitic infections as well as emerging diseases can be valuable bioindicators of the ecology and health of marine mammals. Collecting information about parasite diversity in marine mammals will provide a crucial baseline for assessing their impact on host and ecosystem ecology. New studies on marine mammals in New Zealand and Australian waters have recently added to our knowledge of parasite prevalence, life cycles and taxonomic relationships in the Australasian region, and justify a first host–parasite checklist encompassing all available data. The present checklist comprises 36 species of marine mammals, and 114 species of parasites (helminths, arthropods and protozoans). Mammal species occurring in New Zealand and Australian waters but not included in the checklist represent gaps in our knowledge. The checklist thus serves both as a guide for what information is lacking, as well as a practical resource for scientists working on the ecology and conservation of marine mammals.

scholarly journals A resurrection study reveals limited evolution of thermal performance in response to recent climate change across the geographic range of the scarlet monkeyflower

2020 ◽  
Author(s):  
Rachel Wooliver ◽  
Silas B. Tittes ◽  
Seema N. Sheth
Keyword(s):  
Climate Change ◽  
Thermal Performance ◽  
Thermal Adaptation ◽  
Leading Edge ◽  
Geographic Range ◽  
Average Decrease ◽  
Climate Anomalies ◽  
Trade Offs ◽  
Evolutionary Response ◽  
Recent Climate

AbstractEvolutionary rescue can prevent populations from declining under climate change, and should be more likely at high-latitude, “leading” edges of species’ ranges due to greater temperature anomalies and gene flow from warm-adapted populations. Using a resurrection study with seeds collected before and after a seven-year period of record warming, we tested for thermal adaptation in the scarlet monkeyflower Mimulus cardinalis. We grew ancestors and descendants from northern-edge, central, and southern-edge populations across eight temperatures. Despite recent climate anomalies, populations showed limited evolution of thermal performance curves. However, one southern population evolved a narrower thermal performance breadth by 1.25 °C, which matches the direction and magnitude of the average decrease in seasonality experienced. Consistent with the climate variability hypothesis, thermal performance breadth increased with temperature seasonality across the species’ geographic range. Inconsistent with performance trade-offs between low and high temperatures across populations, we did not detect a positive relationship between thermal optimum and mean temperature. These findings fail to support the hypothesis that evolutionary response to climate change is greatest at the leading edge, and suggest that the evolution of thermal performance is unlikely to rescue most populations from the detrimental effects of rapidly changing climate.

scholarly journals Divergent impacts of warming weather on wildlife disease risk across climates

Science ◽  
2020 ◽  
Vol 370 (6519) ◽  
pp. eabb1702 ◽  
Author(s):  
Jeremy M. Cohen ◽  
Erin L. Sauer ◽  
Olivia Santiago ◽  
Samuel Spencer ◽  
Jason R. Rohr
Keyword(s):  
Climate Change ◽  
Disease Risk ◽  
Disease Outbreaks ◽  
Parasite Prevalence ◽  
Disease Dynamics ◽  
Change Models ◽  
Weather And Climate ◽  
Wildlife Populations ◽  
Host Parasite ◽  
Local Weather

Disease outbreaks among wildlife have surged in recent decades alongside climate change, although it remains unclear how climate change alters disease dynamics across different geographic regions. We amassed a global, spatiotemporal dataset describing parasite prevalence across 7346 wildlife populations and 2021 host-parasite combinations, compiling local weather and climate records at each location. We found that hosts from cool and warm climates experienced increased disease risk at abnormally warm and cool temperatures, respectively, as predicted by the thermal mismatch hypothesis. This effect was greatest in ectothermic hosts and similar in terrestrial and freshwater systems. Projections based on climate change models indicate that ectothermic wildlife hosts from temperate and tropical zones may experience sharp increases and moderate reductions in disease risk, respectively, though the magnitude of these changes depends on parasite identity.

Asynchrony in host and parasite phenology may decrease disease risk in livestock under climate warming: Nematodirus battus in lambs as a case study

Parasitology ◽  
2015 ◽  
Vol 142 (10) ◽  
pp. 1306-1317 ◽  
Author(s):  
OWEN J. GETHINGS ◽  
HANNAH ROSE ◽  
SIÂN MITCHELL ◽  
JAN VAN DIJK ◽  
ERIC R. MORGAN
Keyword(s):  
Climate Change ◽  
Climate Warming ◽  
Disease Risk ◽  
Laboratory Data ◽  
Limited Attention ◽  
Parasite Transmission ◽  
Spring Temperature ◽  
Diagnostic Laboratory ◽  
Infective Larvae ◽  
Host Parasite

SUMMARYMismatch in the phenology of trophically linked species as a result of climate warming has been shown to have far-reaching effects on animal communities, but implications for disease have so far received limited attention. This paper presents evidence suggestive of phenological asynchrony in a host-parasite system arising from climate change, with impacts on transmission. Diagnostic laboratory data on outbreaks of infection with the pathogenic nematode Nematodirus battus in sheep flocks in the UK were used to validate region-specific models of the effect of spring temperature on parasite transmission. The hatching of parasite eggs to produce infective larvae is driven by temperature, while the availability of susceptible hosts depends on lambing date, which is relatively insensitive to inter-annual variation in spring temperature. In southern areas and in warmer years, earlier emergence of infective larvae in spring was predicted, with decline through mortality before peak availability of susceptible lambs. Data confirmed model predictions, with fewer outbreaks recorded in those years and regions. Overlap between larval peaks and lamb availability was not reduced in northern areas, which experienced no decreases in the number of reported outbreaks. Results suggest that phenological asynchrony arising from climate warming may affect parasite transmission, with non-linear but predictable impacts on disease burden. Improved understanding of complex responses of host-parasite systems to climate change can contribute to effective adaptation of parasite control strategies.

scholarly journals Impacts of climate change on the complex life cycles of fish

2012 ◽  
Vol 22 (2) ◽  
pp. 121-139 ◽  
Author(s):  
Pierre Petitgas ◽  
Adriaan D. Rijnsdorp ◽  
Mark Dickey-Collas ◽  
Georg H. Engelhard ◽  
Myron A. Peck ◽  
...  
Keyword(s):  
Climate Change ◽  
Life Cycles ◽  
Complex Life Cycles ◽  
Impacts Of Climate Change

Alpine sparsely vegetated areas in the eastern Qilian Mountains shrank with climate warming in the past 30 years

2018 ◽  
Vol 42 (4) ◽  
pp. 415-430 ◽  
Author(s):  
Biao Zeng ◽  
Fuguang Zhang ◽  
Taibao Yang ◽  
Jiaguo Qi ◽  
Mihretab G Ghebrezgabher
Keyword(s):  
Climate Change ◽  
Climate Warming ◽  
Vegetation Index ◽  
Normalized Difference Vegetation Index ◽  
Regional Scale ◽  
Qilian Mountains ◽  
Visual Interpretation ◽  
Hydrothermal Conditions ◽  
The Past ◽  
Distribution Ranges

Alpine sparsely vegetated areas (ASVAs) in mountains are sensitive to climate change and rarely studied. In this study, we focused on the response of ASVA distribution to climate change in the eastern Qilian Mountains (EQLM) from the 1990s to the 2010s. The ASVA distribution ranges in the EQLM during the past three decades were obtained from the Thematic Mapper remote sensing digital images by using the threshold of normalized difference vegetation index (NDVI) and artificial visual interpretation. Results indicated that the ASVA shrank gradually in the EQLM and lost its area by approximately 11.4% from the 1990s to the 2010s. The shrunken ASVA with markedly more area than the expanded one was mainly located at altitudes from 3700 m to 4300 m, which were comparatively lower than the average altitude of the ASVA distribution ranges. This condition led to the low ASVA boundaries in the EQLM moving upwards at a significant velocity of 22 m/decade at the regional scale. This vertical zonal process was modulated by topography-induced differences in local hydrothermal conditions. Thus, the ASVA shrank mainly in its lower parts with mild and sunny slopes. Annual maximum NDVI in the transition zone increased significantly and showed a stronger positive correlation with significantly increasing temperature than insignificant precipitation variations during 1990–2015. The ASVA shrinkage and up-shifting of its boundary were attributed to climate warming, which facilitated the upper part of alpine meadow in the EQLM by releasing the low temperature limitation on vegetation growth.

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