Great Annual Variation Research Articles

Latitudinal variation in thermal performance of the common coral Pocillopora spp.

Understanding how tropical corals respond to temperatures is important to evaluating their capacity to persist in a warmer future. We studied the common Pacific coral Pocillopora over 44° of latitude, and used populations at three islands with different thermal regimes to compare their responses to temperature using thermal performance curves (TPCs) for respiration and gross photosynthesis. Corals were sampled in the local autumn from Moorea, Guam and Okinawa, where mean±s.d. annual seawater temperature is 28.0±0.9°C, 28.9±0.7°C and 25.1±3.4°C, respectively. TPCs for respiration were similar among latitudes, the thermal optimum (Topt) was above the local maximum temperature at all three islands, and maximum respiration was lowest at Okinawa. TPCs for gross photosynthesis were wider, implying greater thermal eurytopy, with a higher Topt in Moorea versus Guam and Okinawa. Topt was above the maximum temperature in Moorea, but was similar to daily temperatures over 13% of the year in Okinawa and 53% of the year in Guam. There was greater annual variation in daily temperatures in Okinawa than Guam or Moorea, which translated to large variation in the supply of metabolic energy and photosynthetically fixed carbon at higher latitudes. Despite these trends, the differences in TPCs for Pocillopora spp. were not profoundly different across latitudes, reducing the likelihood that populations of these corals could better match their phenotypes to future more extreme temperatures through migration. Any such response would place a premium on high metabolic plasticity and tolerance of large seasonal variations in energy budgets.

Historical Associations and Geographical Distributions of Childhood Epidemics in the United States: An Exploratory, Pre-1955, Analysis at the State Level

The analysis explores possible associations among epidemic childhood diseases over time and in their geographical distributions in the United States. Diseases include diphtheria, polio, measles, scarlet fever, and whooping cough (pertussis). Analysis of their incidence rates is cross-sectional and geographical at the state level using the latitude and longitude of state centroids. All five diseases are analyzed in 1950 controlling for socio-demographic factors. Polio and measles are given an extended historical analysis from 1930 to 1954 and whooping cough from 1940 to 1954. The results show a complex relationship between measles and whooping cough where none was expected. On average, over time, states with higher measles rates also had higher whooping cough rates, and the average weekly incidence of whooping cough lags measles by a delay of two to three weeks. These findings give tentative support for the hypothesis that because of its immune suppressing effects measles causes an increase in whooping cough. The analysis shows little support for disease interference between measles and whooping cough but a possible association between scarlet fever and whooping cough. Geographical distributions of polio, measles, and whooping cough are relatively stable over time, on average, despite great seasonal and annual variations in incidence rates. The method of spatial analysis used here complements conventional metapopulation epidemic models that start in the time domain.

TRI12 based quantitative real-time PCR assays reveal the distribution of trichothecene genotypes of F. graminearum and F. culmorum isolates in Danish small grain cereals

Quantitative real-time PCR assays, based on polymorphisms in the TRI12 gene of the trichothecene pathway, were developed to identify and quantify the trichothecene genotypes producing 3-acetyl-deoxynivalenol (3ADON), 15-acetyl-deoxynivalenol (15ADON) or nivalenol (NIV) in the Fusarium graminearum species complex, Fusarium culmorum, Fusarium cerealis and Fusarium pseudograminearum. These assays were applied on a total of 378 field samples of cereal grain of wheat, barley, triticale, rye and oats collected from 2003 to 2007 to study the trichothecene genotype composition in Danish cereals. The three genotypes, 3ADON, 15ADON and NIV were found in all five cereal species, great annual variation in the occurrence of the trichothecene genotypes was evident with considerable variation between the samples. 3ADON was the dominant genotype in barley, triticale, rye and oats while 15ADON was most dominant in wheat. The NIV genotype was found at low levels in most samples. Study of genotype composition within the Danish F. graminearum and F. culmorum population was based on principal component analysis (PCA). PCA revealed that the dominating genotype of F. graminearum in wheat is 15ADON. For barley, the PCA analysis indicated that the F. graminearum population consisted of all three genotypes, and in triticale, the F. graminearum population consisted mainly of 15ADON genotype. F. culmorum/F. cerealis showed correlation to the NIV genotype in wheat and triticale but not in barley. F. culmorum/F. cerealis also showed some correlation to 3ADON especially in wheat and triticale. Selected wheat and barley samples from 1957 to 2000 showed low amounts of F. graminearum and F. culmorum in general but with a dominance of the 3ADON genotype. 15ADON was not detected in these samples, except for very low amounts in the sample representing the years from 1997 to 2000. Detection of low amounts of the 15ADON genotype in these historical samples and the relatively high amounts of 15ADON genotype in 2003 and following years correspond well with the occurrence of F. graminearum and indicates that the 15ADON genotype was introduced along with F. graminearum around 2000. The amounts of the 3ADON and 15ADON genotypes correlated well with the total amount of DON whereas the amounts of NIV genotype correlated well with the amount of NIV in wheat and triticale but not in barley where the results indicate that Fusarium poae may also contribute to the NIV content.

Remote Sensing Dynamic Estimation of Grass Production in Xilinguole, Inner Mongolia

The monitoring of grass production is not only an important measurement index for researching the spatial dynamic patterns of grassland resources,but also an important basis for the optimal use of grassland resources and for monitoring the balance between grassland forage supply and livestock demand.A total of 371 grassland investigation and remote sensing(RS) data of MODIS-NDVI from 2005-2009 were used to establish a relational model between grass production and RS data.The temporal and spatial distributions of grass production in Xilinguole,Inner Mongolia were simulated and analyzed.The main conclusions are as follows:(1) Each model equation had good relativity,among which the power function model was the most appropriate for the calculation of grass production.Through reservation quadrat data,the accuracy of the production estimation model was 78%.It was feasible for the power function model to be applied for RS monitoring.(2) Grass production in the Xilinguole grassland amounted to an average of 34550000 tons over five years,equivalent to 11120000 tons of hay,and the dry weight per unit area was 567.23 kg/hm2.The spatial distribution of grass production showed a "high east and low west" pattern.(3) An obvious fluctuation in grass production appeared during 2005-2009.The range of hay was 8000000-14000000 tons,and the coefficient of variation was 20.42%.(4) There were greater differences in the single grass yield and the annual variation of different grass types.There were lower grass yields and greater annual variation in desert grassland,and higher grass yields and relatively lesser annual variation in meadow grassland.The spatial and temporal variation of grass yields also had the close relation with the major climate factors(precipitation,temperature,etc.),especially with the influence of precipitation.This research provides a reference for the protection and utilization of grassland resources.

Climatic variation and the distribution of an amphibian polyploid complex

The establishment of polyploid populations involves the persistence and growth of the polyploid in the presence of the progenitor species. Although there have been a number of animal polyploid species documented, relatively few inquiries have been made into the large-scale mechanisms of polyploid establishment in animal groups. Herein we investigate the influence of regional climatic conditions on the distributional patterns of a diploid-tetraploid species pair of gray treefrogs, Hyla chrysoscelis and H. versicolor (Anura: Hylidae) in the mid-Atlantic region of eastern North America. Calling surveys at breeding sites were used to document the distribution of each species. Twelve climatic models and one elevation model were generated to predict climatic and elevation values for gray treefrog breeding sites. A canonical analysis of discriminants was used to describe relationships between climatic variables, elevation and the distribution of H. chrysoscelis and H. versicolor. There was a strong correlation between several climatic variables, elevation and the distribution of the gray treefrog complex. Specifically, the tetraploid species almost exclusively occupied areas of higher elevation, where climatic conditions were relatively severe (colder, drier, greater annual variation). In contrast, the diploid species was restricted to lower elevations, where climatic conditions were warmer, wetter and exhibited less annual variation. Clusters of syntopic sites were associated with areas of high variation in annual temperature and precipitation during the breeding season. Our data suggest that large-scale climatic conditions have played a role in the establishment of the polyploid H. versicolor in at least some portions of its range. The occurrence of the polyploid and absence of the progenitor in colder, drier and more varied environments suggests the polyploid may possess a tolerance of severe environmental conditions that is not possessed by the diploid progenitor. Our findings support the hypothesis that increased tolerance to severe environmental conditions is a plausible mechanism of polyploid establishment.

A comparison of avian use of high- and low-elevation sites during autumn migration in central New Mexico

We compared the migratory bird assemblage at a high-elevation site in central New Mexico (Capilla Peak in the Manzano Mountains) with the bird assemblage at a low-elevation riparian corridor site (Rio Grande Nature Center State Park in Albuquerque). During fall 2001–2003, we used mist nets to sample these bird assemblages. We found greater species richness at the low-elevation site than at the high-elevation site, both overall and for most migratory and resident subgroups. However, at the high-elevation site we captured more species that may have had local origins at high elevations. Over the course of the study, capture rates were similar between sites, but there was greater annual variation in capture rates at the high-elevation site than at the low-elevation site. Several species were captured at higher rates at one site versus the other, and some were captured strictly at one or the other site. Our data showed that both sites supported many species in large numbers, and both riparian and montane habitats in the southwestern U.S.A. should be recognized for their importance as potential stopover sites for migrating birds.

Forecasting changes in amphibian biodiversity: aiming at a moving target.

Amphibian population declines and sudden species' extinctions began to be noted at the beginning of the 1980s. Understanding the causes of the losses is hampered by our poor knowledge of the amphibian fauna in many parts of the world. Amphibian taxa are still being described at a high rate, especially in the tropics, which means that even quantifying species lost as a percentage of the current fauna can be a misleading statistic in some parts of the globe. The number of species that have gone missing is only one measure of the loss of biodiversity. Long-term studies of single-species populations are needed, but this approach has its limits. Amphibian populations often show great annual variation in population size making it difficult, if not impossible, to use short-term studies as a basis for deciding if a population is increasing or decreasing in the long term. Aggregating single studies into databases and searching for patterns of variation is a way of overcoming this limitation. Several databases on species and population time series are available or in development. These records show that declines are continuing worldwide with some species and populations, especially in the tropics and at higher elevations, at greater risk of extinction than others. Unfortunately, amphibian databases with population time series have much less information for the tropics compared to the temperate zone, and less for Africa and Asia compared with Europe and North America. Focusing limited resources using comprehensive statistical designs is a way to maximize the efficiency and effectiveness of monitoring efforts. It is clear that, in the first decades of the twenty-first century, the regions of the globe with the highest diversity of amphibian species will experience the greatest rates of decrease of forests and increase in human population size, fertilizer use, agricultural production, creation of new croplands and irrigation. Many of these changes are likely negatively to affect amphibian species diversity, and their influence must be understood before concluding, at least for amphibians, that the 2010 millennium assessment goal of significantly reversing the rate of loss of Earth's biodiversity can be met.

Exploitation of ringed seals (<i>Phoca hispida</i>) in Greenland

The ringed seal (Phoca hispida) is the most important game for the Inuit hunters of Greenland, providing many of the basic needs in the original culture. It is distributed all around Greenland with the main distribution north of 69°N on the west coast and north of 66°N on the east coast. During 1974-76, studies were conducted in the most important ringed seal catching area, Upernavik, Northwest Greenland, and a total of 7,089 ringed seals were sampled. The methods used for catching ringed seals were categorised into five different groups. The most common hunting method used in the municipality of Upernavik during 1974-76 was netting under the ice, accounting for almost half of the total annual catch. Seals shot on the ice and seals shot at the ice edge accounted for one fifth and one tenth of the annual catch, respectively. In this region seals shot in open water made up about one fifth of the annual catch of ringed seals, while netting in open water contributed only a few percent.Of the seals sampled in Upernavik in 1974-76, 60% were males and 40% were females. In the ringed seal samples collected all around Greenland in the 1980s and 1990s the males comprised 56% and the females 44% (n=923). Similar ratios were found for all age classes and for all hunting methods suggesting either a skewed sex ratio in the ringed seal stock(s) around Greenland or a differencein availability to the hunters of male and female ringed seals. In tagging experiments a higher mobility was found for females than for males, which suggests differences in the behaviour of the two sexes.Catch and trade statistics on ringed seals are reviewed and evaluated for the period of 1954 until 1994, and the seasonal and regional variation is examined. The peak season for ringed seal hunting in Greenland as a whole is from January through May. This is particularly evident for the northern regions, where relatively few ringed seals are taken during the open water season from June to September. In the southern regions, however, the great majority of ringed seals are caught in openwater.In all regions, the catch of ringed seals showed great annual and long-term variation. The variations were not identical in all regions, but similar trends were found for Northwest and Central West, and for Southwest and South. From 1954 to 1994 there was a general, significant increase in the reported catches of ringed seals in west Greenland. For Greenland overall, the catch of ringed seals wasaround 43,000 per year in the 1950s, peaked in the late 1970s at almost 100,000 per year, but since decreased to about 70,000 in the early 1990s.

Inter‐stage survival of wild juvenile Atlantic salmon, Salmo salar L.

A biological model was developed to calculate annual survival between life stages of juvenile Atlantic salmon, Salmo salar L., in Catamaran Brook, a small stream basin (52 km2) in the Miramichi River catchment in New Brunswick, Canada. Seven years’ data (1990–1996) were used in the model. Input variables included: daily fish counts and measurements of parr (3–4 age classes), smolts, and adult salmon at a fish‐counting fence near the stream mouth; biennial quantification of all habitat types along the watercourse; fish density estimated by electric fishing at 30 sites; and estimates of young‐of‐the‐year emigration via stream drift. Continuous recording of stream discharge provided data to assist in interpretation of survival estimates. Annual survival for juvenile salmon in their first 3 years of life in the stream averaged between 31% and 34%. The greatest annual variation (CV = 0.699) occurred at the egg to 0+ (summer) stage with a low of 9.2% survival recorded for a winter with an atypical midwinter flood event; parr and pre‐smolt survival were similarly affected. Survival from egg deposition (after correction for losses caused by predation and retention/non‐fertilization) to smolt emigration was between 0.16% and 0.52%, which is low relative to estimates from many other studies. Survival of smolts to returning 1‐sea‐winter adults (grilse) averaged 8.5%. Potential errors in the computation of the model are discussed, e.g. inaccurate counts of spawning adults during high autumn stream flow. A possible explanation for the low egg to smolt survival was the environmental conditions experienced during various winters. Mean egg survival was 1.3 times higher (39.3%) and egg to smolt survival increased to 1.03% when the two winters characterized by extremely low discharge or midwinter freshets were excluded from the calculation. Density‐dependent factors related to a beaver dam, which limited spawning distribution, may also have contributed to poor survival and increased fry emigration in one year. Environmental factors, particularly winter conditions, in streams such as Catamaran Brook may act as bottlenecks to natural production of Atlantic salmon.

Early-Season Activity and Habitat Characteristics of Terricolous Spider Families (Araneae) in an Appalachian Oak-Mixed Hardwood Forest

Spiders of 24 families were collected by pitfall traps in an oak–mixed hardwood forest in northcentral West Virginia during an 11-wk period in early summer of 1989–1992. All trapped individuals were identified at least to the family level. Quantitative vegetation data allowed assessment of spider habitat associations on a finer spatial scale than previously reported. The Lycosidae dominated each year despite great annual variation in abundance for each family. Percentage of fern coverage on a plot basis was related inversely to abundance of Thomisidae and Gnaphosidae, but related positively to abundance of Linyphiidae, a reflection of the strategies of the families. There was a strong positive correspondence between abundance of the Thomisidae and percentage of oak basal area in the overstory. Pitfall-trap catches were biased slightly toward capture of male spiders; average sex ratio (male:female) for hunting-spider families over the 4 yrs was 8.1:1, and for web-spinners was 2.5:1. Abundance of juvenile spiders (over all families) varied temporally and was related inversely to total abundance.

The primary moult of Curlew Sandpiper in the Ebro Delta, North‐East Spain

The primary moult of Curlew Sandpiper Calidris ferruginea was studied at a staging area in the south of Europe. The duration of primary moult was estimated as 73 days (9 August to 21 October), a shorter period than those reported in the wintering areas. Birds in moult showed a lower speed of fat accumulation than non moulters. An increase in the proportion of moulting birds was detected at the end of the migratory period, probably as a result of a longer staging time of moulting birds in the study area. The number and sex‐ratio of birds in wing moult showed a great annual variation. The brooding system of this species, in which only females give parental care, and the great annual variation in breeding success could be two of the factors that explain the great yearly variation in the moult schedule of Curlew Sandpiper.

Climatic determinants of irrigated rice performance in the Sahel — III. Characterizing environments by simulating crop phenology

Agricultural development programs in most countries of the Sahel seek to increase the intensity of irrigated rice production. Variable crop duration and temperature stresses, however, limit yields and calendrial options. In an effort to characterize climatic constraints to rice double-cropping in the region, a field-based model simulating flowering was combined with models predicting maturity and chilling- and heat-induced spikelet sterility. Simulations were performed for key sowing dates, 38 sites and three genotypes based on 10–33 years of weather records. Sowing between mid-September and mid-November was associated with near-total spikelet sterility due to chilling in all Sahelian environments. Crop duration was longest in November, increasing by 5 days per degree latitude in the continental Sahel. Greatest annual variation in duration was observed in the coastal west and extreme north of the Sahel. Climatic gradients along the courses of the Senegal and Niger rivers were associated with different annual patterns of duration and sterility. Based on the genotypes available to farmers, local rice-rice cropping calendars left little room for alternative calendars. Achieving a greater flexibility for cropping calendars would require the introduction of alternative short-duration varieties. The model permits the zonation of the Sahel in terms of calendrial options and varietal requirements. For a greater spatial resolution of such studies in the future, however, the pooling and digitalization of more weather data is recommended.

The performance of ecological, integrated and conventional nutrient management systems in cereal cropping in Finland

A field was conducted during 1989–1992 in order to study the performance of cereal crops under three different nutrient management systems. The systems were divided into conventional, integrated, and ecological groups according to the fertilizer/organic manure application ratio and crop rotation. Each group was further divided into the crop-production- and animal-production-oriented rotations, the latter including also leys. Average cereal grain yield of the crop-production-oriented rotation was 5% higher than that in the animal-production-oriented one. However, this difference was not significant. Conventional nutrient management systems produced 6% and 32% more cereal grain than the integrated and ecological nutrient management systems, respectively. Difference to the ecological nutrient management system was significant. The 2-year leys in the integrated nutrient management system produced 8% more dry matter than both the conventionally and the ecologically managed leys. This difference was not significant. Nitrogen yield of the integrated leys exceeded that of the conventional leys by 30% and the ecological leys by 10%. The economic result of the systems indicated greater annual variation in the ecologically managed systems. However, by taking into account 30% surcharge on the ecologically produced products, the greatest gross margin/crop was achieved under ecological nutrient management. Gross margin/crop in the conventional and the integrated nutrient management systems did not differ significantly. A significant part of the mineral fertilizers can be replaced with animal manures, legume undercropping or green fallowing. Grass-legume leys also enabled succcessful reduction in mineral fertilization.

A 10 year pollen trapping record from rainforest in northeastern Queensland, Australia

Preliminary results from 10 years of pollen trapping within one of the most extensive, and least disturbed, patches of rainforest in northeast Queensland, are presented. Most pollen grains are derived from canopy or emergent species growing within 10 m of the traps but there is great annual variation in pollen influx and pollen composition. Pollen deposition is concentrated in those traps situated within the canopy and lower totals are recorded for ground, trunk-space and above-canopy traps. Attempts are made to explain these patterns of representation and to assess their value for interpretation of pollen diagrams.

Components of breeding productivity in a marine bird community: key factors and concordance

We estimated components of annual breeding productivity for eight species of marine birds on the Semidi Islands in the western Gulf of Alaska. Mortality of eggs and young, caused primarily by avian predators, accounted for most of the annual variation in productivity. Failure to produce eggs, clutch size variation, and the hatchability of eggs were generally less important. The stage of breeding at which annual productivity was most strongly regulated differed among species. In murres, chick-rearing success accounted for the largest share of annual variation in overall productivity, whereas incubation success was the key factor in fulmars, kittiwakes, and puffins. Although avian predators were the dominant proximate cause of egg and chick losses in some species, food supply seemed ultimately responsible for variation in all the major components of productivity. Concordance of productivity among species was low for the marine bird community as a whole, but selected pairs of species exhibited a greater tendency for high and low productivities to occur in the same years. Compared with the same or similar species outside Alaska, Semidi Islands birds were in one of three categories: (i) species whose productivity was about the same as reported from other areas (fulmars and gulls), (ii) species with comparatively low productivity (murres, puffins, kittiwakes), and (iii) species with similar mean productivity but greater annual variation (cormorants). These patterns suggest that specialized consumers of forage fish experienced food shortages at the Semidi Islands and that surface feeders were more severely affected than divers.

Puerulus and juvenile abundance in the rock lobsterJasus edwardsiiat Stewart Island, New Zealand (Note)

Abstract Settlement of puerulus‐stage New Zealand red rock lobsters (Jasus edwardsii) and abundance of the first three juvenile cohorts were measured from 1981 to 1989 near Halfmoon Bay, Stewart Island. Puerulus settlement on subtidal collectors shows great annual variation. Juvenile abundance, estimated from the number caught in annual diver collections, shows less variation. One‐year‐olds appear less vulnerable to diver sampling than older juveniles. Abundance of 2‐ and 3‐year‐olds is highly correlated with puerulus settlement 2 and 3 years previously. Survival between puerulus and 1+ stages appears to be density‐dependent, but survival of older juveniles does not. Size is inversely related to abundance in 3+ females but not in the other cohorts, suggesting density‐dependent growth between ages 2 and 3. Puerulus settlement rates and processes on shallow inshore reefs appear to be important in determining recruitment strength in this species.

Oceanic and Riverine Influences on Variations in Yield among Icelandic Stocks of Atlantic Salmon

Abstract Data on yields of Atlantic salmon Salmo salar from 59 Icelandic rivers were analyzed with data on streamflows and sea and air temperatures in an attempt to identify why some stocks exhibited more variable yields than others. A group of 24 northern and northeastern rivers, which flowed into seas with wide annual variations in climatic and oceanic conditions (as indicated by coastal sea and air temperatures), exhibited significantly greater variation in Atlantic salmon yields of both grilse and two-sea-winter fish (two winters at sea before first spawning) than the 31 western rivers, which flowed into seas with more stable climatic and oceanic conditions. Yields were the most varied for stocks in the northeast, the region with the greatest annual variation in sea temperatures during spring and summer – the time when smolts migrate to the sea and begin to feed. Rivers with more variable seasonal streamflows also tended to have more variable two-sea-winter Atlantic salmon yields (P < 0.05) but not mo...

Annual variations in the plasma thyroxine level in Microcebus murinus

There is a great annual variation of plasma thyroxine (T 4) in Microcebus murinus. The averages range between 30 and 68 ng/ml from February to July, and fall to 6 ng/ml in November. Long photoperiods seem to be the environmental factor responsible for the summer increase in plasma T 4 as they are for testosterone. There is no apparent phase opposition with annual testosterone variation.

Nitrogen Balance in Fertilizer Application and Plant Production

The investigation comprises several agricultural crops, a Karup locality (56°16' N, 9°9' E) with an average annual precipitation of 775 mm and coarse sand (soil 1), and a Tåstrup locality (55°40' N, 12°18' E) with an average precipitation of 600 mm and clay with fine sand (soil 6). Soils 1 and 6 have 5 and 8 t N/ha in organic matter, respectively, to 50 cm soil depth and an average effective root zone capacity for available water of 60 and 170 mm. Data for soils 1 and 6 in kg N/ha as average (with great annual variation) were for spring barley found to be around the following: mineralization 75 and 135, denitrification 5 and 20, uptake in harvest 105 and 155, leaching 65 and 40, and spring storage 10 and 60, respectively. Wintering and late growing crops reduce the leaching by around 20 kg N/ha. The nitrogen leaching from sandy soil is clearly influenced by variation in fertilization whereas the leaching from clay soil is only a little affected.

Annual Variation in the Plasma Testosterone in Microcebus murinus

There is a great annual variation in plasma testosterone in M. murinus. The averages for a dozen males can reach over 52.4 ng/ml in April and 1.97 ng/ml in October. During the breeding season, the values can reach more than 100 ng/ml and are among the highest found in mammals. The reasons for the important individual variations are open to discussion.