Climate Tolerances and Habitat Requirements Jointly Shape the Elevational Distribution of the American Pika (Ochotona princeps), with Implications for Climate Change Effects

Some of the most compelling examples of ecological responses to climate change are elevational range shifts of individual species, which have been observed throughout the world. A growing body of evidence, however, suggests substantial mediation of simple range shifts due to climate change by other limiting factors. Understanding limiting factors for a species within different contexts, therefore, is critical for predicting responses to climate change. The American pika (Ochotona princeps) is an ideal species for investigating distributions in relation to climate because of their unusual and well-understood natural history as well as observed shifts to higher elevation in parts of their range. We tested three hypotheses for the climatic or habitat characteristics that may limit pika presence and abundance: summer heat, winter snowpack, and forage availability. We performed these tests using an index of pika abundance gathered in a region where environmental influences on pika distribution have not been well-characterized. We estimated relative pika abundance via scat surveys and quantified climatic and habitat characteristics across two North-Central Rocky Mountain Ranges, the Wind River and Bighorn ranges in Wyoming, USA. Pika scat density was highest at mid-elevations and increased linearly with forage availability in both ranges. Scat density also increased with temperatures conducive to forage plant growth, and showed a unimodal relationship with the number of days below -5°C, which is modulated by insulating snowpack. Our results provide support for both the forage availability and winter snowpack hypotheses. Especially in montane systems, considering the context-dependent nature of climate effects across regions and elevations as well as interactions between climatic and other critical habitat characteristics, will be essential for predicting future species distributions.     

Effects of Acomastylis rossii tannins on a mammalian herbivore,the North American pika,Ochotona princeps

 I investigated the effects of tannin consumption, using plant tannins naturally occurring in the diet, on a herbivorous mammal, the North American pika, Ochotona princeps. The objectives were to determine if a high-tannin diet influenced protein and dry matter apparent digestibility, fiber digestibility and production of detoxification by-products. Additionally, I examined the possibility that pikas produce salivary tannin-binding proteins, a potential mechanism for avoiding detrimental effects of tannins. My results demonstrate that although pikas constitutively produce salivary tannin-binding proteins, animals consuming a high-tannin diet of Acomastylis rossii exhibited lower dry matter, protein and fiber digestion and excreted higher concentrations of detoxification by-products. Thus, A. rossii tannins are potential toxins as well as digestibility reducers. I propose a hypothesis coupling detoxification to reduced fiber digestion that is applicable to pikas as well as other mammalian herbivores consuming phenolic-rich diets. Received: 31 July 1995 / Accepted: 9 July 1996     

Four New Species of Eimeria (Protozoa: Eimeriidae) from the Pika Ochotona princeps from Alberta and O. pallasi from Kazakhstan1

SYNOPSIS. Eimeria worleyi n. sp. and Eimeria barretti n. sp. from the pika Ochotona princeps from Alberta and Eimeria pallasi n. sp. and Eimeria shubini n. sp. from the pika Ochotona pallasi from Central Kazakhstan are described. Oocysts of E. worleyi were 12–16 by 10–15 μ (mean 13.5 by 12.5 μ) and spherical to subspherical. E. barretti oocysts were ellipsoidal to slightly ovoid and 27–36 by 21–27 μ (mean 32.9 by 23.8 μ). Oocysts of E. pallasi were ellipsoidal or ovoid and 19–34 by 17–26 μ (mean 26.3 by 21.3 μ). E. shubini oocysts were spherical and 22 μ in diameter. E. kriygsmanni Yakimoff and Gousseff, 1938 of Svanbaev (1958) in O. pallasi, [non] E. kriigsmanni Yakimoff and Gousseff, 1938 in Mus musculus, is a synonym of E. pallasi. E. musculi Yakimoff and Gousseff, 1938 of Svanbaev (1958) in O. pallasi, [non] E. musculi Yakimoff and Gousseff, 1938 in Mus musculus, is a synonym of E. shubini.     

Variation in pika (Ochotona collaris,O. princeps) vocalizations within and between populations

Understanding geographic call variation can resolve evolutionary and behavioural questions, yet the factors influencing divergent acoustic signals remain poorly understood in mammals. We explored call variation between collared pikas in Yukon and Alaska and American pikas in Alberta, and between individuals within a population of collared pikas. Classification trees were used to determine the extent of call divergence between populations and the elements of calls driving these differences. Pika populations had significant differences in call structure, and individual pikas were classified to their correct populations with up to 94% accuracy. To investigate possible mechanisms responsible for interspecific variability, we tested the acoustic adaptation hypothesis by using a playback experiment to explore whether American and collared pika calls transmit with less degradation across their own species' habitat than the habitat of their congener. We found no support for the acoustic adaptation hypothesis. Geographic call variation in these two species of pikas likely reflects genetic divergence, and may be a result of separate evolutionary histories. We calculated the potential for individual coding for both time and frequency measurements of calls. High frequency harmonics showed greater between‐ than within‐individual variation, and may act as sources of information regarding individual identity.     

Determining natal dispersal patterns in a population of North American pikas (Ochotona princeps) using direct mark-resight and indirect genetic methods

A combination of direct (mark-resight) and indirect geneticmethods were used to investigate natal dispersal patterns andgenetic population structure in a population of North Americanpikas, Ochotona princeps. Pikas are small lagomorphs found intalus habitat of alpine areas throughout western North America.Adult pikas are individually territorial and rarely disperse.I used multilocus DNA fingerprinting to identify the parentsof juvenile animals. The settlement pattern of marked juvenilesand the pattern of relatedness of pikas across the study sitewas then examined within the study area. Although juvenilesborn at the study site exhibited a philopatric settlement pattern,an isolation-by-distance analysis did not reveal clusters ofhighly related individuals within the population. The F_ST estimatesuggests little genetic differentiation between populations2 km apart, and average DNA fingerprinting band-sharing amongadults was similar to values reported for outbred species. Anaverage of 34% of the adult population was replaced each winterby immigrants. DNA fingerprinting band-sharing analysis suggeststhat these immigrants had dispersed short, intermediate, andlong distances. These findings differ from earlier studies whichused observations of marked animals only to characterize dispersalpatterns. Direct observations of marked juveniles had documenteda philopatric settlement pattern, little or no dispersal outof natal populations, and no direct evidence of long distancemovement. Of the three major hypotheses proposed to explainthe evolution of dispersal in birds and mammals, competitionfor resources, competition for mates, and inbreeding avoidance,the results of this study support a competition for resourceshypothesis, where the key resource is territory     

Joint study on the teratogenic sensitivity of the Pika (Ochotona rufescens rufescens) to selected drugs

A collaborative study was conducted to investigate the teratological susceptibility of the Pika (Ochotona rufescens rufescens) to selected teratogenic chemicals: cyclophosphamide, 6-mercaptopurine, 5-fluorouracil, 6-aminonicotinamide, actinomycin D, ethylurethan, ampicillin, tetracycline, thalidomide, diphenylhydantoin, hypervitaminosis A, aspirin, dexamethasone, betamethasone and bredinin. Some of the chemicals were shown to be teratogenic in the Pika, but this animal was generally more resistant to their teratogenicity than the rabbit and rodents. In the Pika, thalidomide did not induce any typical limb defects, which have been produced in the rabbit. Pikas reproduce well and appear to have no substantial disadvantages as an animal species for teratological studies. Thus, the Pika may be useful as a new non-rodent species for teratological testings.     

Eavesdropping on the Neighbourhood: Collared Pika (Ochotona collaris) Responses to Playback Calls of Conspecifics and Heterospecifics

The acoustic environment, composed in part by the vocalizations of sympatric animals, is a major source of information and can be used to fine-tune behavioural decisions. Active assessment of alarm calls within and between mammal species is not fully understood. We explored the behavioural responses of collared pikas to con- and heterospecific vocalizations, in order to determine whether they selectively attend to these calls. Pikas increased their vigilance after playback of alarm calls of heterospecific mammals (marmots and ground squirrels), but responded most strongly to conspecific calls. While responses to playback calls of their own, of neighbours and of a stranger did not differ, pikas did discriminate between individual callers in a habituation-discrimination experiment. The ability to make use of information from different sources in their acoustic environment likely facilitates pikas' behavioural decisions that affect foraging, predator avoidance and nepotism.     

The effect of habitat fragmentation on dispersal patterns, mating behavior, and genetic variation in a pika (Ochotona princeps) metapopulation

 Habitat fragmentation is becoming increasingly common, yet, the effect of habitat spatial structure on population dynamics remains undetermined for most species. Populations of a single species found in fragmented and nonfragmented habitat present a rare opportunity to examine the effect of habitat spatial structure on population dynamics. This study investigates the impact of highly fragmented habitat on dispersal patterns, mating behavior, and genetic variation in a pika (Ochotona princeps) population with a mainland-island spatial structure. Juvenile dispersal patterns in fragmented habitat revealed that individuals tended to disperse to neighboring habitat patches. However, within-patch band-sharing scores from multilocus DNA fingerprints did not differ from what would be expected if individuals were assorting randomly among habitat patches each year. Multiple, short-distance dispersal targets for juveniles and occasional long-distance dispersal events suggest that habitat fragmentation on this scale has not resulted in restricted dispersal and a genetically subdivided population. Although pikas tended to mate with the closest available partner, DNA fingerprinting band-sharing scores between mated pairs were consistent with a random mating hypothesis. Random mating in this population appears to be an incidental effect of dispersal in a fragmented habitat. This pattern is distinct from that found in nonfragmented habitat (large talus patches) where mating was non-random and consistent with mating between individuals of intermediate relatedness. DNA fingerprinting data revealed within-species variation in the mating habits of the pika directly attributable to habitat spatial structure. Received: 4 November 1996 / Accepted: 30 June 1997     

The Effect of Coprophagy on the Digesta Passage through the Gut of the Daurian Pika Ochotona dauurica (Ochotonidae,Lagomorpha)

Biology Bulletin - Fibrous food passage through the digestive tract of Daurian pika (Ochtona dauurica) was studied by means of multiple dose marking of food by neutral plastic markers. Contrary to...     

Forage selection by Royle's pika (Ochotona roylei) in the western Himalaya,India

Forage selection decisions of herbivores are often complex and dynamic; they are modulated by multiple cues, such as quality, accessibility and abundance of forage plants. To advance the understanding of plant–herbivore interactions, we explored foraging behavior of the alpine lagomorph Royle's pika (Ochotona roylei) in Kedarnath Wildlife Sanctuary, India. Pika bite counts on food plants were recorded through focal sampling in three permanently marked plots. Food plant abundance was recorded by traditional quadrat procedures; forage selection was estimated with Jacob's selection index. Multiple food-choice experiments were conducted to determine whether forage selection criteria would change with variation in food plant composition. We also analyzed leaf morphology and nutrient content in both major food plants and abundantly available non-food plants. Linear regression models were used to test competing hypotheses in order to identify factors governing forage selection. Royle's pika fed primarily on 17 plant species and each forage selection decision was positively modulated by leaf area and negatively modulated by contents of avoided substances (neutral detergent fiber, acid detergent fiber, acid detergent lignin and tannin) in food plants. Furthermore, significance of the interaction term “leaf size × avoided substance” indicates that plants with large leaves were selected only when they had low avoided substance content. The forage selection criteria did not differ between field and laboratory experiments. The parameter estimates of best fit models indicate that the influence of leaf size or amount of avoided substance on pika forage selection was modulated by the magnitude of predation risk.     

Physiological Responses in Wild Broodstocks of the Caspian Kutum (Rutilus frisii kutum) Subjected to Transportation Stress

Caspian Kutum (Rutilus frisii kutum) broodstocks in the wild were subjected to 2 different densities (100 and 300 kg m^?3) for 2 hr of transport, and their physiological responses were examined. Fifteen fish were placed into the plastic container for each replicate and blood was taken at 0, 10, 30, 60, and 120 min after transportation in different densities. Mean levels of cortisol and glucose as primary and secondary responses to the stress were significantly different between densities. Significant differences in both densities were observed in cortisol for all times and glucose levels at 30 and 120 min after transportation, and the highest values were found in both densities at 120 min. Testosterone concentrations declined considerably in the first 10 min, and then they showed a gradual decrease with a significant difference between 2 densities at 10 and 30 min after transportation. Serum estradiol reached the lowest level at 120 min after transportation, and differences were significant between the 2 densities after 30 min. Based on the results, it was concluded that Kutum broodstocks are sensitive to transport, especially at high density. Therefore, welfare during transport should be considered.     

Comparative Physiological and Proteomic Analysis Reveals the Leaf Response to Cadmium-Induced Stress in Poplar (Populus yunnanensis)

Excess amounts of heavy metals are important environmental pollutants with significant ecological and nutritional effects. Cdmium (Cd) is of particular concern because of its widespread occurrence and high toxicity. We conducted physiological and proteomic analyses to improve our understanding of the responses of Populus yunnanensis to Cd stress. The plantlets experienced two apparent stages in their response to Cd stress. During the first stage, transiently induced defense-response molecules, photosynthesis- and energy-associated proteins, antioxidant enzymes and heat shock proteins (HSPs) accumulated to enhance protein stability and establish a new cellular homeostasis. This activity explains why plant photosynthetic capability during this period barely changed. During the second stage, a decline of ribulose-1, 5-bisphosphate carboxylase (RuBisCO) and HSP levels led to imbalance of the plant photosynthetic system. Additionally, the expression of Mitogen-activated protein kinase 3 (MPK3), Mitogen-activated protein kinase 6 (MPK6) and a homeobox-leucine zipper protein was higher in the second stage. Higher expression of caffeoyl-CoA O-methyltransferase (CCoAOMT) may regulate plant cell wall synthesis for greater Cd storage. These genes may be candidates for further research and use in genetic manipulation of poplar tolerance to Cd stress.     

Seasonal Prevalence of Lyme Disease Spirochetes in a Heterothermic Mammal,the Edible Dormouse (Glis glis)

In Europe, dormice serve as competent reservoir hosts for particular genospecies of the tick-borne agent of Lyme disease (LD) and seem to support them more efficiently than do mice or voles. The longevity of edible dormice (Glis glis) and their attractiveness for ticks may result in a predominance of LD spirochetes in ticks questing in dormouse habitats. To investigate the role of edible dormice in the transmission cycle of LD spirochetes, we sampled skin tissue from the ear pinnae of dormice inhabiting five different study sites in south western Germany. Of 501 edible dormice, 12.6% harbored DNA of LD spirochetes. Edible dormice were infected most frequently with the pathogenic LD spirochete Borrelia afzelii. The DNA of B. garinii and B. bavariensis was detected in ca. 0.5% of the examined individuals. No spirochetal DNA was detectable in the skin of edible dormice until July, 6 weeks after they generally start to emerge from their obligate hibernation. Thereafter, the prevalence of spirochetal DNA in edible dormice increased during the remaining period of their 4 to 5 months of activity, reaching nearly 40% in September. Males were more than four times more likely to harbor LD spirochetes than females, and yearlings were almost twice more likely to be infected than adults. The seasonality of the prevalence of LD spirochetes in edible dormice was pronounced and may affect their role as a reservoir host in respect to other hosts.     

Effects of altitudinal change on the auditory bulla in Ochotona daurica (Mammalia, Lagomorpha)

The lengths and widths of body parts are influenced to a considerable extent by the environment. Along with increasing altitude, wings of arthropods degenerated or even disappeared so that a trend of degeneration on their acoustic systems appeared. We measured 131 adult skulls of daurian pikas, Ochotona daurica , in order to know whether the degeneration will happen in mammals. Our results show that both the size and relative size of auditory bulla of daurian pikas were negatively correlated with altitude and this change was significant. However, the ear length showed an opposite trend. We suggest that lower oxygen concentration, constantly strong winds and lack of resources at high altitude are responsible for the decrease in the size of the auditory bulla. Besides thermoregulation for large different temperatures of day and night in high altitude, larger external ears of the pika help detect the direction of the predator and could compensate for a relatively small bulla.     

Genetic Differentiation of the Forest Crested Lizards,Calotes emma alticristatus Schmidt, 1925 and C. emma emma Gray, 1845(Squamata: Agamidae) Relating to Climate Zones in Thailand

In Thailand, the forest crested lizard, Calotes emma consists of two subspecies, C. emma alticristatus Schmidt, 1925 and C. emma emma Gray, 1845. This study was performed to determine the genetic diversity and differentiation of C. emma from 16 different localities throughout Thailand. A total of 116 samples were analyzed using the mitochondrial cytochrome c oxidase subunit 1(CO1). Of these, 65 and 51 of C. e. alticristatus and C. e. emma were classified into 23(N1 – N23) and 21(S1 – S21) haplotypes, respectively. There was no shared haplotype between subspecies or between different populations within each subspecies. These haplotypes were classified into four(north-A to north-D) and three(south-A to south-C) haplogroups of C. e. alticristatus and C. e. emma, respectively. Phylogenetic analyses retrieved four lineages(classified as I to IV). Lineages I and II contained the four haplogroups of C. e. alticristatus,whereas lineage III and IV contained three haplogroups of C. e. emma. These two subspecies live separately in different climate zones, i.e. C. e. alticristatus is found in an equatorial winter dry climate, whereas C. e. emma inhabits areas with an equatorial monsoonal climate.     

Features of Metabolomic Profiles in Different Stages of Ontogenesis in Prunella vulgaris (Lamiaceae) Grown in a Climate Chamber

Russian Journal of Bioorganic Chemistry - Metabolic analysis of methanol extracts of leaves of Prunella vulgaris L. (Lamiaceae) grown in a climate chamber has been carried out using gas...