京都大学 / 0048 / 新制・課程博士 / 博士(理学) / 甲第18798号 / 理博第4056号 / 新制||理||1583(附属図書館) / 31749 / 京都大学大学院理学研究科地球惑星科学専攻 / (主査)准教授 齊藤 昭則, 教授 田口 聡, 教授 余田 成男 / 学位規則第4条第1項該当 / Doctor of Science / Kyoto University / DGAM

Communication is a behavioral strategy used by species in the competition for survival and reproduction. Animals produce signals that are sent to receivers and occasionally transmit information that can be beneficial in a variety of contexts including avoiding predators, locating food resources, and maintaining the pair bond between partners. Researchers are interested in if auditory signals are variable and if the variability is biologically meaningful to receivers. Some species, such as siamang, sing duets as their form of acoustic communication and these duets have been studied for a variety of purposes such as investigating their structure, variability, and functionality. Siamang are a species of gibbon that combine a finite number of call units into structurally complex sequences in rule-governed ways, hereby conveying different contextual situations. Some wild gibbon species have demonstrated variation in the temporal structure of their duets and the distinctiveness in acoustic timing is unique enough for researchers to distinguish among individuals and groups based on their duet contributions. The process of coordinating and producing a uniquely timed duet could function in relation to the formation and maintenance of the pair bond. This dissertation analyzed the temporal variation and call order of wild siamang (Symphalangus syndactylus) duets that are comprised of four distinct sequences comprised of several note types. Previous research has provided detailed descriptions of captive siamang duets that include category descriptions of four call types: grunting, introduction, interlude, and great call. While these descriptions provide a general understanding of the structure of siamang duets, they can be confusing and difficult to study empirically due to their arbitrary nature. For instance, the siamang great call has been described as occurring in over 30 variants and in stable, or typical, and unstable, or atypical forms. The stable or typical form of the great call has been described to occur only after the male’s first bitonal scream. This previous research did not measure the timing of sequences through entire duets or conduct individual note analyses. Also, the most detailed investigations of siamang duets were conducted with captive animals and therefore wild siamang duets have not been quantitatively analyzed. This dissertation research measures the temporal variation of wild siamang duet call types, and the call order of individual notes in the US-II phrase. The findings will provide a more objective description of the siamang duet as well as determine if it has a more stereotyped or flexible nature. Also, in the wake of globalization, duets and other behaviors (such as travel) could be sensitive to anthropogenic disturbances. So, I am interested in how wild siamang might be impacted by human presence. The three main objectives of this dissertation are: 1) document the temporal variation in the call types of wild siamang; 2) document variation in the call order of wild siamang US-II phrases; and 3) document how wild siamang travel is impacted by anthropogenic noise. The study was conducted at 4 remote field sites in northern Sumatra, Indonesia from August 2017 through May 2018. With the assistance of a research team, I recorded acoustic and behavioral data from 10 siamang groups and two individual females. I collected acoustic data using a combination of autonomous recording units and handheld recording devices while following the study subjects on foot. I marked GPS points during behavioral scans and conducted experimentally induced noise playback experiments. I analyzed the audio data with the software program Raven Pro 1.6 and spectrograms were produced with a 512-point (11.6 ms) Hann window (3 dB bandwidth = 135 Hz), with 50% overlap and a 512-point DFT, yielding time and frequency measurement precision of 2.9 ms and 43.1 Hz. I conducted statistical testing in R Studio Version 1.3.959 in conjunction with the statistics lab at Southern Illinois University. In Chapter 3, I performed multilevel regression analysis in the form of a Generalized Linear Mixed Model (GLMM) in order to investigate temporal variation the time spent singing call types (grunting, introduction, interlude, and great call) accounting for differences between songs, groups, and field sites. I used a Bayesian hierarchical model to avoid calculating estimates using data with repeated and imbalanced sampling, and explicitly model variation within individuals, between songs, between groups, and field sites. In Chapter 4, I used the Levenshtein Distance (LD) method for investigating structural variation in the call order of US-II phrases in the siamang duet. The LD method is a quantitative technique for measuring the similarity of sequences and to quantify the differences between strings of data. In Chapter 5, I used the Friedman test to compare the means of distances traveled in 5-minute intervals in the following conditions: pre-playback, cicada (control), traffic, jackhammer, and music. I used post hoc tests with Bonferroni correction to analyze the pairwise comparisons of the five experimental conditions. Overall, the results suggest support of previous studies on the variability of the gibbon duet and animal travel in response to noise. In Chapter 3, I found some temporal variation in call types to exist at all levels of the modeling but only statistically significant when comparing the field sites of Ketambe and Kutapanjang. Relating to the functionality of total call duration, I did not find significant differences in the behavioral categories before or after any of the calls regardless of their total duration. In Chapter 4, I found US-II phrases are not as stereotyped as previous descriptions have suggested. The mean LD distances were higher than those compared by other duetting primates. Also, the results from one-way ANOVA and Games-Howell Post Hoc Testing showed significant mean differences between groups. In Chapter 5, I found siamang are impacted by noise as they traveled further after the anthropogenic noise playback experiments compared to pre-playback travel. However, the pairwise comparisons were not statistically significant and therefore I could not determine which noise condition caused the change in travel distance. Collectively, the results of this dissertation suggest that there is considerable variability in both wild siamang call types and call order in a previously described stereotyped phrase, and that wild siamang travel away is impacted by introduced anthropogenic noise. What this contributes to the field of vocalization studies is further support that precise measurement of song parameters gives a better understanding of song structure than somewhat arbitrary written descriptions. It is important to have descriptions of notes produced in songs, but to understand how those notes relate to each other, an individual note analysis and rigorous statistical methodology is necessary. The variation found in this dissertation could be due to the unique siamang response to their partner’s timing in the process of forming the pair bond. But as the siamang duet is thought to have multiple functions, the temporal variation could also be transmitting other information such as individual and group identity while functioning in territorial defense. In addition, anthropogenic noise caused the animals to change their travel behavior and this suggests it could be harmful if faced on a regular basis. Anthropogenic noise can be detrimental if it occurs in home ranges of species that are territorial and facing shrinking habitats due to continued human encroachment. In order to understand if these findings are biologically meaningful and to have firmer conclusions, future long-term studies will need a larger data set over longer periods of time. It is also important to have a larger data set and compare more siamang groups that live in various noise levels and measure variables such as caloric intake, daily travel, copulations, and number of offspring.

No description available.

Moderate livestock grazing is often identified as a useful management tool for sustaining biodiverse grassland communities and has long been practiced in Scandinavian mountains. Despite of a growing number of studies focusing on grazing effects along elevational gradients worldwide, there is still limited knowledge of how grazing intensity varies over time and how it affects plant communities on species and functional group level. Moreover, the majority of existing studies are conducted in enclosures with controlled stocking rate, while free-range grazing with a highly varied livestock number is the common practise in Scandinavia. Therefore, the aim of this study was to quantify free-range grazing intensity over the growing season along an elevational gradient and to evaluate how grazing affects plant communities on species, functional group and community level. In order to quantify grazing intensity, we conducted a grazer exclusion experiment along an elevational gradient in Norway in the growing season of 2019. We quantified grazing intensity as the difference in dry above-ground biomass between grazed and caged plots and analyzed plant composition on community and functional group level as well as recorded species-specific grazing damage and potentially influential abiotic factors. To capture the effects of temporal variation in grazing we also relocated caged and grazed plots in four-week intervals during the growing season. We demonstrated that grazing intensity gradually decreased with elevation and elevation explained 77% of the variation in grazing among sites. Lower grazing intensity at high elevation is likely related to decreasing plant productivity and differences in plant community composition along the gradient. Grazers reduced the biomass of graminoids and forbs in the intensively grazed lower sites. Grazing damage varied among sites for five of the eight most commonly grazed plant species, which was mainly driven by a higher grazing damage in the intermediate site (900m a.s.l.). Selective grazing was observed in three sheep-dominated study sites. Grazing intensity did not significantly vary during the growing season at any site, possibly due to weak temporal effects of an overall short growing season. In accordance with other studies, we demonstrated that grazing homogenized plant community composition in actively grazed sites that were relatively species rich. To conclude, livestock grazing can help maintain biodiverse semi-natural grasslands, yet when grazing is applied as a management tool in the mountainous landscapes, we suggest considering that grazing intensity, and therefore its effects, will vary with elevation.

Increasing levels of air pollution are prompting researchers to develop more reliable air pollution modeling approaches in order to protect the public and the environment from toxic contaminants and airborne pathogens. Although land use regression has long been used to assess exposure to air pollution, researchers are increasingly using machine learning algorithms to quantify the concentration of harmful pollutants—for this study black carbon (BC) and particle number (PN). Additionally, researchers are moving away from using fixed-site data in favor of using mobile monitoring data in a variety of locations to develop hourly empirical models of particulate air pollution. This study uses secondary data describing BC and PN pollutant levels, which are obtained from roads that bikers share in the more rural location of Blacksburg (VA). Machine learning (ML) algorithms are then built to develop accurate and reliable short-term empirical prediction models. Different pre-processing methods for the mobile monitoring data and various input variables are tested to assess how ML can be used effectively in this process. Three types of time-average models are developed (daytime, hourly average, and one second models). Various combinations of spatial and temporal input variables are used in the short-term models. The impact of adding more spatiotemporal variables (e.g., emissions) to machine learning models to improve model performance is assessed in the short-term models. Incorporating spatial and temporal autocorrelation is intended to develop more sophisticated validation approaches for identifying ML performance patterns—the goal of which is to predict concentration levels more accurately in comparison to using raw data without data reprocessing. The results show that the model developed using refined disaggregated data is able to detect the spatial distribution of the pollutant concentration at equivalent levels as the smoothed data models, although the latter display fewer errors. The performance of the short-term model including all variables is equivalent to the model omitting emissions. The ML results are compared to earlier stepwise regression model results, suggesting that ML has the ability to improve both long-term and short-term model accuracy. Our findings indicate that ML demonstrates higher predictive capacity in comparison to stepwise regression. The results from this study may be useful in enhancing the performance of ML through the incorporation of different data preprocessing tasks, as well as showing how different input variables contribute to the ML modeling process. The findings from this study could be used toward the development of environmental/eco-friendly routes that would decrease the risk for exposure to harmful vehicle-related emissions. / Doctor of Philosophy / Air pollution is a major environmental threat to human health, claiming the lives of millions of people each year, primarily as a result of fine particulate matter entering the respiratory system. As such, it is important to develop reliable and accurate air pollution modeling approaches in order to protect the public and the environment from toxic contaminants and pathogens in the air. Although an approach known as land use regression has long been used to assess exposure to air pollution, researchers are increasingly using machine learning (ML) algorithms to quantify the concentration of harmful pollutants—for this study black carbon and particle number, which is a generic assessment that captures a number of known airborne hazards. Additionally, researchers are moving away from using fixed-site data in favor of using mobile monitoring data in a variety of locations to develop hourly empirical models of particulate air pollution. In this study, machine learning algorithms are developed using secondary data collected from roads that bikers share, which are representative of pollution levels of particle number and black carbon in the more rural location of Blacksburg (VA), in order to develop accurate and reliable short-term empirical prediction models. Different pre-processing methods of the mobile monitoring data and various input variables are tested to assess how machine learning can be efficiently used in this process. Our findings indicate that machine learning demonstrates higher predictive capacity in comparison to stepwise regression. The results from this study are expected to be useful in enhancing the performance of machine learning through the incorporation of different data preprocessing tasks, as well as how different input variables contribute to the machine learning modeling process. The findings from this study could assist transportation planners and other stakeholders better assess pollution risks for bike riders and pedestrians. As such, this study's findings could be used toward the development of environmental/eco-friendly routes that would decrease the risk for exposure to harmful vehicle-related emissions.

The response of global soil respiration (Rs) to climate change determines how long the land can continue acting as a carbon sink in the future. This dissertation research identifies how temporal and spatial variation in environmental factors affects global scale Rs modeling and predictions of future Rs under global warming. Chapter 1 describes the recommend time range for measuring Rs across differing climates, biomes, and seasons and found that the best time for measuring the daily mean Rs is 10:00 am in almost all climates and biomes. Chapter 2 describes commonly used surrogates in Rs modeling and shows that air temperature and soil temperature are highly correlated and that they explain similar amounts of Rs variation; however, average monthly precipitation between 1961 and 2014, rather than monthly precipitation for a specific year, is a better predictor in global Rs modeling. Chapter 3 quantifies the uncertainty generated by four different assumptions of global Rs models. Results demonstrate that the time-scale of the data, among other sources, creates a substantial difference in global estimates, where the estimate of global annual Rs based on monthly Rs data (70.85 to 80.99 Pg C yr-1) is substantially lower than the current benchmark for land models (98 Pg C yr-1). Chapter 4 simulates future global Rs rates based on two temperature scenarios and demonstrates that temperature sensitivity of Rs will decline in warm climates where the level of global warming will reach 3°C by 2100 relative to current air temperature; however, these regional decelerations will be offset by large Rs accelerations in the boreal and polar regions. Chapter 5 compares CO2 fluxes from turfgrass and wooded areas of five parks in Blacksburg, VA and tests the ability of the Denitrification-Decomposition model to estimate soil temperature, moisture and CO2 flux across the seasons. Cumulatively, this work provides new insights into the current and future spatial and temporal heterogeneity of Rs and its relationship with environmental factors, as well as key insights in upscaling methodology that will help to constrain global Rs estimates and predict how global Rs will respond to global warming in the future. / Ph. D.

Thesis (MScConsEcol)--University of Stellenbosch, 2011. / ENGLISH ABSTRACT: Anthropogenic habitat transformation and subsequent fragmentation of natural vegetation is regarded as one of the largest threats to biodiversity in the world. The Cape Floristic Region (CFR) in the Western Cape Province of South Africa is classified as a biodiversity hotspot due to its high plant species diversity and endemism. Increasing growth in agricultural activities in this region has contributed to fragmentation of pristine natural vegetation. A diverse assemblage of small mammal species are found in this region, but very little is known with regard to their ectoparasite diversity. More importantly, no information is available on the effect of fragmentation on parasite burdens or species assemblages. The aims of the study were first to record relative density, average body size and body condition of an endemic rodent, Rhabdomys pumilio, trapped in two habitat types (pristine natural areas and remnant fragments). Secondly, compare diversity and species composition of ectoparasite species on this rodent in the two habitat types. In addition, body size measurements of the two most abundant flea species were recorded and compared for the two habitat types. Lastly, temporal variation in mean abundance of fleas, mites, ticks and the louse were recorded within a habitat fragment surrounded by vineyards. Three hundred and ten individuals of the Four-striped mouse, R. pumilio, were trapped and euthanized at 8 localities (4 remnant habitat fragments and 4 pristine natural areas) in the CFR. All ectoparasites were removed and identified. A total of 8361 ectoparasites that consisted of 6 flea, 1 louse, 8 mites and 11 tick species were recorded. Mites and fleas were found to be more abundant on mice during cool wet months, whereas ticks and the louse were more abundant during the hot dry months of the year. Rodent host body size was larger and they were in better body condition in remnant fragments compared to pristine natural localities. A positive body size relationship was found between the flea, Listropsylla agrippinae, and the host, with larger fleas recorded on rodents that occur in fragments. Mean abundance and prevalence of overall ectoparasites combined and separately for ticks, mites, louse and fleas were higher in fragments compared to natural localities. The study shows that R. pumilio is host to a large diversity of ectoparasite species in the CFR. Moreover, habitat fragments within agricultural landscapes can facilitate higher parasite burdens and prevalence in rodent populations. This can lead to an increase in disease risk given that several of the parasite species are important vectors of pathogens that can cause disease in domestic, wild animals and humans. / AFRIKAANSE OPSOMMING: Menslike habitat transformasie en die daaropvolgende fragmentasie van natuurlike plantegroei word beskou as een van die grootste bedreigings vir biodiversiteit in die wêreld. Die Kaap Floristiese Streek (KFS) in die Wes-Kaap Provinsie van Suid-Afrika word geklassifiseer as 'n biodiversiteit ‘hotspot’ as gevolg van sy hoë plant spesies diversiteit en endemisme. Toenemende groei in landbou-aktiwiteite in hierdie streek het ook bygedra tot die fragmentasie van ongerepte natuurlike plantegroei. 'n Diverse versameling van die klein soogdier spesies word in hierdie streek aangetref, maar baie min is bekend met betrekking tot hul ektoparasiet diversiteit. Meer belangrik, geen inligting is beskikbaar oor die effek van fragmentasie op parasietladings of spesie samestelling nie. Die doel van die studie was eerstens om relatiewe digtheid, gemiddelde liggaams grootte en kondisie van Rhabdomys pumilio aan te teken vir twee habitat tipes (ongerepte natuurlike area en oorblyfsel fragment). Tweedens was die diversiteit en spesiesamestelling van ektoparasiete op R. pumilio vergelyk vir die twee habitat tipes. Daarna was die liggaams grootte metings van die twee mees volopste vlooi spesies aangeteken en vergelyk vir die twee habitat tipes. Laastens was die seisonale variasie van die gemiddelde hoeveelheid vlooie, myte, bosluise en die luis aangeteken binne 'n habitat fragment omring deur wingerde. Drie honderd en tien individue van die vier-gestreepte muis, R. pumilio, was gevang op 8 plekke (4 oorblyfsel habitat fragmente en 4 ongerepte natuurlike areas) in die KFS en daarna was die diere uitgesit. Alle ektoparasiete was verwyder en geïdentifiseer. 'n Totaal van 8361 ektoparasiete wat bestaan het uit 6 vlooie, 1 luis, 8 myte en 11 bosluis spesies was aangeteken. Myte en vlooie gevind was meer volop op muise tydens die koel nat maande, terwyl bosluise en die luis meer volop was gedurende die warm droë maande van die jaar. Knaagdier gasheer liggaam was groter en in 'n beter kondisie in die habitat fragmente in vergelyking met ongerepte natuurlike areas. 'n Positiewe liggaam grootte verwantskap was tussen die vlooi, Listropsylla agrippinae, en die gasheer gevind, met groter vlooie aangeteken op knaagdiere wat voorkom in fragmente. Gemiddelde hoeveelheid en voorkoms van die totale ektoparasiete gekombineer en afsonderlik vir bosluise, myte, die luis en vlooie was hoër in fragmente in vergelyking met natuurlike areas. Die studie toon dat R. pumilio gasheer is vir 'n groot verskeidenheid van ektoparasiet spesies in die KFS. Daarbenewens kan habitat fragmente binne landbou landskappe hoër parasietladings en voorkoms in knaagdier bevolkings fasiliteer. Dit kan lei tot 'n toename in siekte risiko, gegee dat verskeie van die parasietspesies belangrike vektore is van patogene wat siektes kan veroorsaak in huishoudelike, wilde diere en die mens.

Nos próximos 85, no Brasil, espera-se um aumento real de até 6°C na temperatura média do ar, além de uma queda de 5−20% nas taxas de precipitação. Neste sentido, o aquecimento do clima deve sobrepujar adaptações locais, e a sobrevivência dependerá da plasticidade fisiológica das espécies, além de sua capacidade de dispersão. Atualmente, a previsão das respostas ecológicas e fisiológicas dos os organismos a estas alterações compreende um dos principais desafios dos ecofisiologistas. Os lagartos são particularmente sensíveis ao aquecimento global, uma vez que alterações de temperatura podem alterar sua performance para níveis sub−ótimos, restringindo os períodos de atividade com impacto direto em sua história natural. Em lagartos de regiões com baixa variabilidade climática (próximas ao Equador), a baixa resiliência às alterações ambientais, associada a opções restritas de dispersão e habitats cuja temperatura do ar (Ta) seja superior aos seus ótimos termais, entre outros fatores, fazem destas populações as mais vulneráveis ao aquecimento. Neste estudo, foram realizadas análises espaciais e temporais no intuito de avaliar a vulnerabilidade de populações de lagartos do complexo Tropidurus torquatus no Cerrado brasileiro, e se a resiliência é influenciada pela magnitude da flexibilidade intrapopulacional de fisiologia termal e de performance. O estudo consta de três abordagens principais: (1) comparações de dados de temperatura corporal (Tb) e temperatura operativa (Te, temperaturas hipotéticas para termoconformadores); temperaturas corporais preferenciais (Tp média e amplitude dos valores de Tset), e índices quantitativos de regulação de temperatura e de qualidade do ambiente termal (db, de e E) de Tropidurus com dados de literatura para espécies dos gêneros Anolis, Liolaemus e Sceloporus, bem como de 60 populações pertencentes a 21 espécies de tropidurídeos dos domínios da Caatinga, Amazônia, Cerrado e Chaco, e outras regiões como a costa do Peru e as ilhas Galápagos; (2) análises dos padrões intra e interespecíficos de variabilidade das capacidades de performance para velocidade e resistência em populações de T. torquatus, T. oreadicus, T. etheridgei e T. catalanenis, e estimação do impacto de um aumento da Ta em 3°C sobre a performance e a atividade destes lagartos num cenário de aquecimento, e (3) examinar as variações temporais e geográficas de idade, taxas de crescimento, maturidade sexual e longevidade em espécimes de T. torquatus em duas regiões a distintas latitudes; a variação temporal foi estimada através do estudo de amostras coletadas em cada uma das regiões em épocas distintas (década de 1960 e 2012), enquanto as comparações geográficas foram feitas apenas com base nas amostras recentes destas regiões (2012). Os resultados confirmam as hipóteses sugerindo que o comportamento termorregulatório aumenta acompanhando os parâmetros de latitude e altitude e que os lagartos tropicais e de áreas situadas a baixas altitudes tendem a se comportar como termoconformadores. Estima-se que populações tropicais com pouco ou nenhum comportamento termorregulatório presentes em ambientes com restrições termais impostas por parâmetros altitudinais (de baixas ou elevadas altitudes) são os mais vulneráveis ao aquecimento do clima. Em contraste, as estepes e montanhãs da Patagônia, bem como outras áreas montanhosas, representam refúgios termais para populações de lagartos que serão progressivamente forçados a se deslocar para estes ambientes. Dentre os tropidurídeos, um padrão geral sugere que o comportamento termorregulatório ambiental diminui na direção do Equador, particularmente devido à menor variabilidade ambiental. Na maioria das linhagens, valores similares e mais elevados de Tb e Tp em relação a valores de Ta apontam para uma condição plesiomórfica, provavelmente relacionada à ocorrência em ambientes florestais. O comportamento termorregulatório limitado ou ausente, combinado com grandes proporções de Tb e Te acima dos ótimos termais aumentam os riscos de superaquecimento e limitam o tempo de atividade especialmente nas regiões central e setentrional do Cerrado. As curvas de performance demonstram que os intervalos termais de desempenho (B80’s) e as margens de segurança aumentaram com a variação de temperatura, mas diminuíram com a variação anual de precipitação. Os resultados das comparações entre os padrões de variação temporal e regional do crescimento das populações de T. torquatus sugerem que o aquecimento do clima afeta o crescimento dos indivíduos, que tendem a ser maiores em regiões de clima mais quente. O aumento nos valores de Ta das últimas décadas aceleraram as taxas de crescimento, anteciparam a maturação sexual e encurtaram a expectativa de vida nas duas regiões estudadas. Embora em curto prazo os efeitos do aumento nos valores de Ta possam parecer vantajosos no que tange o crescimento e a reprodução, é plausível estimar uma queda geral no desempenho de todas as populações a longo prazo. Devido às grandes proporções de valores de Te atualmente superando o limite superior de B80 e das preferenda termais de T. torquatus e T. etheridgei na região Central, à capacidade de dispersão restrita e à baixa variabilidade na biologia termal de T. torquatus nas matas quentes de galeria, espera-se que os maiores impactos devam se concentrar sobre as populações das regiões central e setentrional. / In Brazil, an increase in the mean air temperature (Ta) of up to 6°C and a trend of decreasing rainfall by 5−20% are expected within 85 years. Climate warming is expected to overrun local adaptation and survival will depend on the plasticity and dispersal options and abilities. Predicting how organisms will respond these changes is one of the most critical challenges for contemporary ecophysiologists. Lizards are particularly sensitive to global warming, as temperature changes could shift overall performance to suboptimal levels, restricting time for activity. The low resilience to environmental changes of lineages from regions of low climatic variability (close to the Equator) combined with low dispersal options and current habitats’ Ta that exceeds their thermal optima, among other factors, make these populations the most vulnerable to warming. We conducted spatial and temporal analyses to assess the vulnerability of populations of the Tropidurus torquatus species complex in the Brazilian Cerrado and whether resilience is influenced by the magnitude of flexibility in thermal physiology and performance that exists within populations using three different approaches: (1) we compare data on body (Tb) and operative temperatures (Te, “null temperatures” for nonregulating animals), preferred body temperatures (mean T/p and Tset Tet range), and quantitative indices of temperature regulation and quality of the thermal environment (b, d e and E) for Tropidurus with data from the literature for Anolis, Liolaemus, and Sceloporus, and for 60 populations of 21 species of tropidurids from the Caatingas, Amazonia, Cerrado, Chaco, and other regions as the coast of Peru and Galapagos Islands; (2) We analyze patterns of variability in the performance capacities for velocity and endurance within and among populations of T. torquatus, T. oreadicus, T. etheridgei and T. catalanenis, and estimate the impact of a Ta increase by 3°C on performance and activity of these lizards in a warming scenario; and (3) we examine the geographic and temporal variation of individual age, growth rates, age at sexual maturity and longevity in specimens of T. torquatus at two sites at different latitudes; temporal variation was estimated studying subsamples at each site collected in 1960s and 2012, whereas the geographical comparisons were performed between the two subsamples collected in 2012 both at the two sites. Our results confirm the hypotheses by suggesting that thermoregulatory behavior increases with latitude and altitude and that tropical and lowland lizards behave as thermoconformers. We estimate that tropical populations with poor or no thermoregulatory behavior that inhabit stressful environments (open and low elevation sites) are the most vulnerable to rising temperatures. In contrast, Patagonia steppe and mountains as well as other montane environments represent future thermal refuges for lizards that would eventually be forced to retreat to these environments. Within tropidurids, a general pattern suggests that the thermoregulatory behavior decreases towards the Equator, particularly due to environmental constrains and probably to the low environmental variation. In most lineages, similar and higher Tb and Tp with respect to Ta point to a plesiomorphic condition, probably related to earlier forested environments. Constraint or no thermoregulation combined with the large proportions of Tb and Te above the thermal optima augment the risk of overheating and preclude time of activity particularly in the central and northernmost regions of the Cerrado. Based on the thermal performance curves, thermal breadths (B80’s) and safety margins increased with the thermal variation and decreased with the variation of annual precipitation. The results on the temporal variation and between sites differences on the growth patterns suggest that warming positively affect growth in T. torquatus. The increase of Ta of the last decades accelerated growth rates, anticipated sexual maturity and shortened the life−span at both sites. Although short-term effects of an increasing Ta’s may seem beneficial with respect to growth and reproduction, we predict an overall decay in the fitness response in all populations in the long term. Due to the large proportions of T e ’s currently exceeding the upper limit of the B 80 and thermal preferenda of T. torquatus and T. etheridgei at the Central site and the limited dispersal capacity and low variability on the thermal biology of T. torquatus in the warm gallery forest, the northernmost and Central populations are expected to experience the highest impact.

Recently, Hudson Bay experienced unidirectional trends in temperature, sea-ice extent, time of break-up, and length of the open-water season. Predicted impacts on population dynamics of ice-associated species include habitat loss and shift in prey availability. The ringed seal (Phoca hispida) depends on a stable ice platform with sufficient snow depth and a productive open-water season for reproduction and survival. Evidence of ringed seal sensitivity to environmental variations has been reported, but mechanisms involved were poorly understood. In western Hudson Bay, density, life-history traits, and diet of ringed seals were monitored over two decades, providing an opportunity to understand the effects of climatic variations on the population dynamics of this long-lived carnivore. Ringed seal density was estimated through strip-transect analyses after aerial surveys were flown in western Hudson Bay in late spring during the annual moult in the 1990s and 2000s. During these periods, ringed seals were also sampled from Inuit subsistence fall harvests In Arviat, NU, and ages, reproductive status, percentage of pups in the harvest, body condition, and diet were assessed. Strong inter-annual variations in these parameters were observed, and a decadal cycle was suggested and related to variations in the sea-ice regime. The cold and heavy ice conditions that prevailed in western Hudson Bay in 1991-92 likely induced a decrease in pelagic productivity, reducing the availability to ringed seals of sand lances (Ammodytes sp.), their major prey. The nutritional stress endured, combined with a strong predation pressure, led to a decrease in ringed seal reproductive performances, pup survival, and density during the 1990s. The recovery of ringed seal demographic parameters and number in the 2000s was associated with the immigration of pups, juveniles, and young adults into western Hudson Bay. Impact of current climatic trends on ringed seal population dynamics was not apparent, but considering the limited range of environmental variations tolerated by ringed seals, the response of this species to climate warming might be of a catastrophic type. Ringed seals were found to be good indicators of ecosystem changes, and long-term monitoring of the species in Hudson Bay should be a priority.

Recently, Hudson Bay experienced unidirectional trends in temperature, sea-ice extent, time of break-up, and length of the open-water season. Predicted impacts on population dynamics of ice-associated species include habitat loss and shift in prey availability. The ringed seal (Phoca hispida) depends on a stable ice platform with sufficient snow depth and a productive open-water season for reproduction and survival. Evidence of ringed seal sensitivity to environmental variations has been reported, but mechanisms involved were poorly understood. In western Hudson Bay, density, life-history traits, and diet of ringed seals were monitored over two decades, providing an opportunity to understand the effects of climatic variations on the population dynamics of this long-lived carnivore. Ringed seal density was estimated through strip-transect analyses after aerial surveys were flown in western Hudson Bay in late spring during the annual moult in the 1990s and 2000s. During these periods, ringed seals were also sampled from Inuit subsistence fall harvests In Arviat, NU, and ages, reproductive status, percentage of pups in the harvest, body condition, and diet were assessed. Strong inter-annual variations in these parameters were observed, and a decadal cycle was suggested and related to variations in the sea-ice regime. The cold and heavy ice conditions that prevailed in western Hudson Bay in 1991-92 likely induced a decrease in pelagic productivity, reducing the availability to ringed seals of sand lances (Ammodytes sp.), their major prey. The nutritional stress endured, combined with a strong predation pressure, led to a decrease in ringed seal reproductive performances, pup survival, and density during the 1990s. The recovery of ringed seal demographic parameters and number in the 2000s was associated with the immigration of pups, juveniles, and young adults into western Hudson Bay. Impact of current climatic trends on ringed seal population dynamics was not apparent, but considering the limited range of environmental variations tolerated by ringed seals, the response of this species to climate warming might be of a catastrophic type. Ringed seals were found to be good indicators of ecosystem changes, and long-term monitoring of the species in Hudson Bay should be a priority.