Trends In Population Density Research Articles

Influence of Salt Marsh Size and Landscape Setting on Salt Marsh Nekton Populations

Recruitment- and predation-related effects on populations of salt marsh codominants mummichog (Fundulus heteroclitus) and pinfish (Lagodon rhomboides), were examined based on marsh size and landscape setting. Six island marshes—three small island marshes (SIM) ~40–1,000 m2 and three large island marshes (LIM) ~3,000–10,000 m2—were paired with six expansive fringing marshes (EFM), each >76,000 m2 in size and located within ~1.0 km of a paired SIM or LIM. Over a 2-year period, triannual collections at these sites assessed F. heteroclitus, L. rhomboides, and predator finfish populations as well as habitat characteristics. No significant population density trends were apparent for L. rhomboides young-of-year (YOY) or year-one-and-older (Y1+) cohorts based on marsh size or were any significant differences in density apparent among marsh types. F. heteroclitus YOY and Y1+ densities differed significantly among marsh types demonstrating a positive relationship between density and marsh size. Larval and juvenile F. heteroclitus abundances were significantly lower within SIM than LIM and EFM. Although larval F. heteroclitus abundances between LIM and EFM did not differ significantly, juvenile abundances did, suggesting mortality constrained LIM juvenile abundances. A significant negative relationship of F. heteroclitus to predator finfish density and a significant negative relationship of predator finfish density to low marsh area/perimeter (access restriction) estimates suggest that predation on F. heteroclitus is greater within SIM and LIM than within EFM. Habitat and landscape level attributes can affect resident nekton population regulation and these effects should be considered relative to the life history traits of targeted species when managing coastal resources.

Trends in Population Density and Shell Length of the Planktonic Larva Ruditapes philippinarum in Ariake Bay

Trends in Population Density and Shell Length of the Planktonic Larva Ruditapes philippinarum in Ariake Bay

Global forecasts of urban expansion to 2030 and direct impacts on biodiversity and carbon pools

Urban land-cover change threatens biodiversity and affects ecosystem productivity through loss of habitat, biomass, and carbon storage. However, despite projections that world urban populations will increase to nearly 5 billion by 2030, little is known about future locations, magnitudes, and rates of urban expansion. Here we develop spatially explicit probabilistic forecasts of global urban land-cover change and explore the direct impacts on biodiversity hotspots and tropical carbon biomass. If current trends in population density continue and all areas with high probabilities of urban expansion undergo change, then by 2030, urban land cover will increase by 1.2 million km(2), nearly tripling the global urban land area circa 2000. This increase would result in considerable loss of habitats in key biodiversity hotspots, with the highest rates of forecasted urban growth to take place in regions that were relatively undisturbed by urban development in 2000: the Eastern Afromontane, the Guinean Forests of West Africa, and the Western Ghats and Sri Lanka hotspots. Within the pan-tropics, loss in vegetation biomass from areas with high probability of urban expansion is estimated to be 1.38 PgC (0.05 PgC yr(-1)), equal to ∼5% of emissions from tropical deforestation and land-use change. Although urbanization is often considered a local issue, the aggregate global impacts of projected urban expansion will require significant policy changes to affect future growth trajectories to minimize global biodiversity and vegetation carbon losses.

Time trends in fish populations in metropolitan France: insights from national monitoring data

Using the electrofishing database of the French National Agency for Water and Aquatic Environment (Onema), the time trends of 48 freshwater fish taxa at 590 sites monitored for at least 8 years from 1990 to 2009 were investigated. The results demonstrated that species richness increased steadily from the beginning of the monitoring period. This is congruent with the finding that the number of species displaying a significant increase in spatial distribution or abundance was greater than those showing a significant decrease. Some species, however, had declined both in occurrence and abundance, e.g. tench Tinca tinca, common bream Abramis brama, brown trout Salmo trutta and European eel Anguilla anguilla. The species showing the most spectacular colonization were non-native, e.g. topmouth gudgeon Pseudorasbora parva, wels catfish Silurus glanis and asp Aspius aspius. The time trends in population density were related to the maximal body size, habitat requirement, occurrence and abundance and the status (i.e. native or exotic) but not to the spawning temperature.

Using acoustic cue statistics in matrix population models to study short‐term and long‐term marine mammal population dynamics in the northern Gulf of Mexico.

Acoustics is emerging as a viable tool for determining population trends of deep diving marine mammals in addition to conventional transect‐line visual observations which are often limited by weather conditions, short‐time surface presence, costs, etc. In September 2010, following the recent oil spill in the Gulf of Mexico, the Littoral Acoustic Demonstration Center (LADC) conducted a passive acoustic experiment as part of a study of short‐term and long‐term effects of the oil spill on the resident population of marine mammals. Environmental Acoustic Recording System (EARS) buoys were redeployed in three locations: 9 mi, 23 mi, and 50 mi away from the Deepwater Horizon‐oil spill site. LADC previously collected data at these locations in 2001, 2002, 2007. The pre‐spill data are used as a baseline for estimating long‐term population trends. Densities of acoustic phonations of sperm whales, beaked whales, and dolphins are extracted from collected data and used for point estimates of the resident population density. LADC extensive work on an individual acoustic identification is reviewed in the context of mark‐recapture statistics used in matrix population models. Trends in population density after the spill are presented and discussed. [Research is supported by ONR and NSF. Ship services donated by Greenpeace.]

Temporal distribution of weather catastrophes in the USA

The temporal distributions of the nation’s four major storm types during 1950–2005 were assessed, including those for thunderstorms, hurricanes, tornadoes, and winter storms. Storms are labeled as catastrophes, defined as events causing $1 million or more in property losses, based on time-adjusted data provided by the insurance industry. Most catastrophic storms occurred in the eastern half of the nation. Analysis of the regional and national storm frequencies revealed there was little time-related relationship between storm types, reflecting how storm types were reported. That is, when tornadoes occurred with thunderstorms, the type producing the greatest losses was the one identified by the insurance industry, not both. Temporal agreement was found in the timing of relatively high incidences of thunderstorms, hurricanes, and winter storms during 2002–2005. This resulted in upward time trends in the national losses of hurricane and thunderstorm catastrophes, The temporal increase in hurricanes is in agreement with upward trends in population density, wealth, and insurance coverage in Gulf and East coastal areas. The upward trends in thunderstorm catastrophes and losses result from increases in heavy rain days, floods, high winds, and hail days, revealing that atmospheric conditions conducive to strong convective activity have been increasing since the 1960s. Tornado catastrophes and their losses peaked in 1966–1973 and had no upward time trend. Temporal variability in tornado catastrophes was large, whereas the variability in hurricane and thunderstorm catastrophes was only moderate, and that for winter storms was low.

Association of Phytophthora cinnamomi with White Oak Decline in Southern Ohio.

A decline syndrome and widespread mortality of mature white oak tree (Quercus alba) associated with wet and low-lying areas has been recently observed in southern Ohio forests. Previous studies have isolated Phytophthora cinnamomi from white oak rhizospheres. In 2008 and 2009, P. cinnamomi population densities in two healthy and two declining white oak stands at Scioto Trail State Forest were quantified and potential roles of three environmental drivers of Phytophthora spp.-induced decline were assessed: soil texture, soil moisture, and topography. Significantly higher P. cinnamomi propagule densities were found in declining stands in both years but propagule densities were not associated with soil moisture content. Trends in population densities were not correlated with soil moisture or topographic position within field sites. There was a positive, exponential relationship between overall P. cinnamomi population levels and soil moisture on a seasonal scale in 2008 but not 2009. Sites with greater soil clay content were associated with greater decline. Effects of P. cinnamomi inoculum and periodic flooding on root health of 1-year-old potted white oak trees grown in native soil mixes in the greenhouse were examined. Root systems of potted oak were significantly damaged by soil inoculation with P. cinnamomi, especially under flooding conditions. Results of these studies support the hypothesis that P. cinnamomi is a contributing agent to white oak decline in southern Ohio.

Long-Term Trends in Population Density and Reproductive Success of Long-Eared OwlAsio otusin Brandenburg, Germany

The density and reproduction of Long-eared Owls Asio otus were studied in a 5000 ha study area of Havelland, Brandenburg, Germany from 1984 through 2007. Locations of territorial Long-eared Owls were mapped from the end of January until the end of April, counts of fledged young were made from mid-May until August. Long-eared Owls nested in conifer groupings or isolated woods in the agricultural landscape. Nearly all nesting took place in nests of crows Corvidae, mainly in Scots Pine Pinus sylvestris trees. A total of 867 breeding attempts were recorded; 335 (36.6%) pairs were successful in fledging 1468 young. The reproductive output was 1.57 fledglings for all pairs that attempted to nest, and 4.31 fledglings per successful pair. Average population density for the 24 years was 72.7 breeding pair/100 km2 (range 40–118 breeding pair/100 km2). For the time frame of 1984–2007 there was no trend in the number of breeding pairs or in the number of young fledged. After 1990, when conservation-focused farming in...

Detecting trends in desert tortoise population growth: elusive behavior inflates variance in estimates of population density

Assessing the recovery of the federally listed Mojave population of desert tortoises Gopherus agassizii requires detecting subtle changes in population size over a period of many years. The methods that have been employed by the US Fish and Wildlife Service to estimate population density of desert tortoises are inadequate for detecting modest trends in population density, partly due to a hidden variance in a parameter (g0) that corrects for the proportion of tortoises that are inactive and thus unavailable for sampling when population density is being assessed. We used small dataloggers to record the activity of tortoises throughout their active season, and derived daily esti- mates of g0, which we compared with the 2004 estimate published by the US Fish and Wildlife Ser- vice. Due to the substantial variation in animal activity that we found within and among days during the active season, we used a daily method to estimate density. We found that this method, while pro- viding a more accurate assessment of g0, translates into estimates of density with coefficients of vari- ation that are 4 larger than previously reported due to the variation in g0 and n (number of animals encountered). This discrepancy could adversely influence managers' perceptions of population recovery for desert tortoises, and could undermine any ability to monitor the efficacy of recovery actions for populations.

Resistance Allele Frequency to Bt Cotton in Field Populations of Helicoverpa armigera (Lepidoptera: Noctuidae) in China

Resistance evolution in target insects to Bacillus thurningiensis (Bt) cotton, Gossypium hirsutum L., is a main threat to Bt cotton technology. An increasing trend of population density of Helicoverpa armigera (Hübner) (Lepidoptera: Noctuidae) has been observed since 2001 in Qiuxian County (Hebei, China), where Bt cotton has been planted dominantly since 1998. This region was selected in 2006 and 2007 for estimating frequency of gene alleles conferring resistance to Bt cotton by screening the F1 progeny from single-pair cross between field-collected male and laboratory female of the Bt-resistant strain of H. armigera (F1 screen). F1 offspring from each single-pair line were screened for resistance alleles based on larval growth, development, and survival on Bt cotton leaves for 5 d. Two-year results indicated that ≈20% of field-collected males carried resistance alleles. The conservative estimate of the resistance allele frequency was 0.094 (95% CI, 0.044–0.145) for 2006 and 0.107 (95% CI, 0.055–0.159) for 2007. This is the first report of resistance allele frequency increase to such a high level in the field in China. Long-term adoption of Bt sprays, dominant planting of single-toxin–producing Bt cotton, and lack of conventional cotton refuge system might accelerate the resistance evolution in the region.

Resistance Allele Frequency to Bt Cotton in Field Populations of <I>Helicoverpa armigera</I> (Lepidoptera: Noctuidae) in China

Resistance evolution in target insects to Bacillus thurningiensis (Bt) cotton, Gossypium hirsutum L., is a main threat to Bt cotton technology. An increasing trend of population density of Helicoverpa armigera (Hübner) (Lepidoptera: Noctuidae) has been observed since 2001 in Qiuxian County (Hebei, China), where Bt cotton has been planted dominantly since 1998. This region was selected in 2006 and 2007 for estimating frequency of gene alleles conferring resistance to Bt cotton by screening the F1 progeny from single-pair cross between field-collected male and laboratory female of the Bt-resistant strain of H. armigera (F1 screen). F1 offspring from each single-pair line were screened for resistance alleles based on larval growth, development, and survival on Bt cotton leaves for 5 d. Two-year results indicated that approximately equal to 20% of field-collected males carried resistance alleles. The conservative estimate of the resistance allele frequency was 0.094 (95% CI, 0.044-0.145) for 2006 and 0.107 (95% CI, 0.055-0.159) for 2007. This is the first report of resistance allele frequency increase to such a high level in the field in China. Long-term adoption of Bt sprays, dominant planting of single-toxin-producing Bt cotton, and lack of conventional cotton refuge system might accelerate the resistance evolution in the region.

Control of the sugarcane click beetle Melanotus okinawensis Ohira (Coleoptera: Elateridae) by mass trapping using synthetic sex pheromone on Ikei Island, Okinawa, Japan

Mass trapping with a synthetic sex pheromone lure to control the sugarcane click beetle Melanotus okinawensis Ohira (Coleoptera: Elateridae) was conducted in an agricultural area (81.4 ha) on Ikei Island (158.3 ha), Okinawa, Japan, with 970–1,000 traps (10.6 traps/ha) from 2000 to 2005. The total number of beetles captured by 725 traps was 22,701 in 2000, which decreased to 27.6% in 2005. Mean trap catch by 50 monitoring traps showed a similar decrease (to 26.1%) during the six-year trapping. Mean catches by 10 monitoring traps in an untreated area (Miyagi Island: 107 ha) did not decrease. Trends of population density in the area estimated by release-recapture experiments indicated a population decrease of about 90% from 2000 to 2005. Furthermore, the number of wild adults discovered on sugarcane and collected by hand in the treated area also decreased every year, by up to 86.2% by 2005. The population in the untreated area did not decrease consistently. The mating rates of females collected weekly in 2001 and 2002 were 73.9 and 85.7% in the treated area, which was slightly lower than in untreated areas (92.7 and 96.7%). We defined the male removal rate as the proportion of reduced survival duration. We estimated the male removal rate using two methods. The estimate obtained from the number of recaptured individuals was 0.345 while the estimate obtained from the difference in sex ratios between the treated and untreated areas was 0.319. These values appeared too small to explain the great reduction in population density in the treated area. Nevertheless, these results indicated that mass trapping with a high density of sex pheromone traps may effectively reduce an isolated population of M. okinawensis.

An experimental investigation of texture evolution during continuous cooling

Textural evolution during a controlled cooling experiment has been quantified using bulk textural characterizations (mean crystal length, total numbers of crystals and modal olivine content) and crystal size distributions (CSDs). The experiments involved subliquidus melting of an olivine–glass mixture followed by cooling at a constant rate (92 °C h − 1 ) through the crystallization interval. Measured changes in population density, n( L), for small (< 0.3 mm) euhedral olivine crystals are shown to be consistent with a uniform crystal growth rate of 6.0 × 10 − 7 mm s − 1 . The CSD trends for larger (> 0.3 mm) skeletal crystals are broadly consistent with an exponentially increasing nucleation rate and with a uniform growth rate of 2.0 × 10 − 5 mm s − 1 . However, the textural development of these crystals cannot be explained solely in terms of homogeneous nucleation and growth. Additional factors influencing the development of textures in the skeletal zone of the charges include grain impingement and development of skeletal overgrowths on the top of a layer of seed crystals. CSD data is ideal for analyzing texture development because it is sensitive to the detailed structure of the crystal population and can be used to detect variations in behavior between different size classes. Here, population density trends for various crystal size classes are used as a tool for estimating the kinetics of crystal growth and nucleation in a cooling igneous system. This type of analysis can be used to gain insight into crystallization processes from CSDs without relying on assumptions regarding CSD shape. Examples of the use of population density trends in the evaluation of natural systems are provided for the case of crystallization in porphyritic olivine chondrules and in komatiite flows.

Seasonal Trends in Population Density, Distribution, and Movement of American Dippers Within a Watershed of Southwestern British Columbia, Canada

Abstract American Dippers concentrate on low-elevation streams during fall and winter in many parts of their range; however the breeding origin relative to the wintering location is poorly understood. Our objectives were to identify seasonal changes in the density and distribution of American Dippers, to classify the migratory behavior of the local population, and to determine the origin of winter migrants within a coastal watershed of British Columbia, Canada. During 1999–2002, we color banded 522 dippers and radio-tagged 14 in the Chilliwack River watershed. Using mark-resighting techniques, we identified peak densities on the main river during early November (9.8 ± 1.4 [SE] birds per stream km), which was nearly 5 times higher than in early July (2.1 ± 0.3 birds per stream km). The watershed's total population size, estimated from November surveys, was 429 ± 64 [SE] dippers in 1999, 682 ± 79 in 2000, 697 ± 123 in 2001, and 550 ± 72 in 2002. The majority (79– 90%) of the dipper population seasonally migrated, primarily moving from the main river in fall and winter to the higher-elevation tributaries in spring. The remaining dippers (10– 16%) remained resident on the main river year-round. Migrants showed a high degree of winter site fidelity with 67% returning to the same site on the Chilliwack River for 2 or more years. Given the population's defined structure and predictable seasonal movements, this study has implications for applying American Dipper populations as indicators of water and habitat quality in North American watersheds. Tendencias Estacionales en Densidad Poblacional, Distribución y Movimiento de Cinclus mexicanus en una Cuenca del Sudoeste de la Columbia Británica, Canadá Resumen. Cinclus mexicanus se concentra en ríos ubicados a baja elevación en muchas partes de su rango durante el otoño y el invierno; sin embargo, se conoce poco sobre la relación entre el sitio originario de reproducción y la localización durante el invierno. Nuestros objetivos fueron identificar los cambios estacionales en la densidad y la distribución de C. mexicanus, clasificar el comportamiento migratorio de la población local y determinar el origen de los migrantes invernales en una cuenca costera de la Columbia Británica, Canadá. Entre 1999 y 2002 anillamos con bandas de color 522 individuos de C. mexicanus y seguimos con radio-telemetría 14 individuos en la cuenca del Río Chilliwack. Usando técnicas de marcado y re-avistamiento, identificamos densidades pico en el río principal durante principios de noviembre (9.8 ± 1.4 [EE] aves por km de río), lo que fue casi 5 veces más alto que a principios de julio (2.1 ± 0.3 aves por km de río). El tamaño total de la población de la cuenca, estimado a partir de los censos de noviembre, fue 429 ± 64 [EE] aves en 1999, 682 ± 79 en 2000, 697 ± 123 en 2001 y 550 ± 72 en 2002. La mayoría (79–90%) de la población de C. mexicanus migró estacionalmente, moviéndose principalmente desde el río principal en el otoño y el invierno a los tributarios de mayor elevación en la primavera. Los individuos restantes (10–16%) permanecieron como residentes en el río principal durante todo el año. Los migrantes mostraron un alto grado de fidelidad a los sitios de invierno, con un 67% de los individuos retornando al mismo sitio en el Río Chilliwack por 2 años o más. Dada la estructura definida de la población y los movimientos estacionales predecibles, este estudio señala que las poblaciones de C. mexicanus pueden ser usadas como indicadores de la calidad del agua y del hábitat en las cuencas de América del Norte.

BENTHIC COMMUNITIES IN THE RIVER NILE, EGYPT III- MEIOFAUNA AT HELWAN REGION

The present work is the third in a series titled Benthic communities in the River Nile, Egypt. The first dealt with aquatic stages of Insecta (Ramadan et al, 1998) and the second dealt with Mollusca (Ramadan et ai, 2000). The present work is the first to deal quantitatively with the ecology of the Egyptian Nile Meiofauna. It is hoped to be a contribution to the data base necessary for the development of the resources of the River-Nile. Monthly samples were collected from the eastern and western sides of five stations in the Nile at Helwan region (Industrial area, 30 km. South Cairo) from June 1997 to May 1998. The average standing crop of meiofauna in the whole investigated area during the period of study was 27.3 organisms/10 cm weighing 5.06 mg. fresh weight/10 cm . Nematoda was the dominant group, contributing about 66.3% of the total population density (P. D.) followed by Ostracoda (32.1%). Regarding biomass, Ostracoda occupied the first position contributing 55.5 % of the total biomass of Meiofauna, followed by Nematoda (42.9%). Summer and autumn represented the most productive seasons. The temporal average biomass followed the same trend of population density (P. D.)with some deviation. Nature of the sediment was the primary factor affecting the meiofaunal abundance. A highly significant negative correlation was revealed between the total number of macrobenthos and meiobenthos in (he sampled area. Similarity, a negative correlation was observed between the ostracod Chlamydotheca unispinosa Baird, 1862 and the macrobenthic gastropod Valvata nilotka Jickeli, 1874. The scarce occurence of harpacticoid copepods makes the Nematoda/Copepoda ratio reaches its maximum value indicateing heavy polluted area.

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Global Change and Arctic Ecosystems: Conclusions and Predictions from Experiments with Terrestrial Invertebrates on Spitsbergen

Extensive studies on invertebrates from Ny-Ålesund, Spitsbergen, Svalbard and more limited data on aphids from Abisko, Sweden, produced the following main conclusions: (1) The population response to raised summer temperatures differed between the above and the below ground species, both in terms of speed and magnitude. (2) Similar animal communities responded differently to similar temperature manipulations on sites with different vegetation cover and composition. (3) For soil animals the between-year and between-site variations in population densities, were greater than the differences produced by the temperature manipulation experiments at any one site in any year. (4) Infrequent extreme climatic events strongly influence long-term trends in population density and community composition. (5) The population response of invertebrates to climate warming is greatest and most rapid at the coldest sites. (6) The spatial distribution of the above ground insect herbivores on their host plant is temperature limited. (7) The numerical abundance of flying predators/parasitoids of the above-ground herbivores is low. (8) The spatial distribution of some predators may be thermally restricted and less extensive than that of their prey. (9) Habitat temperature is the driving variable determining the flight activity patterns of insects. (10) Increased summer temperatures may alter or disrupt the seasonal patterns of insect emergence, particularly in species where the life cycle is cued into the seasonal rhythm. (11) The common species of arctic soil mites and Collembola are well adapted to survive enhanced summer temperatures, providing that moisture is not limited. (12) Water availability during the summer growing period is probably of greater significance than temperature in determining the survival and success of many arctic soil invertebrate groups. (13) Arctic soil microarthropod species are well adapted to survive and operate at subzero and low positive summer temperatures. (14) Freeze-thaw events represent critical points in the life history of the microarthropods. (15) Supercooling points are sometimes poor indicators of the capacity of arctic soil microarthopods to survive low temperatures. From these findings predictions are made as to how high arctic communities will respond to predicted changes in climate.

Global Change and Arctic Ecosystems: Conclusions and Predictions from Experiments with Terrestrial Invertebrates on Spitsbergen

Extensive studies on invertebrates from Ny-Alesund, Spitsbergen, Svalbard and more limited data on aphids from Abisko, Sweden, produced the following main conclusions: (1) The population response to raised summer temperatures differed between the above and the below ground species, both in terms of speed and magnitude. (2) Similar animal communities responded differently to similar temperature manipulations on sites with different vegetation cover and composition. (3) For soil animals the between-year and between-site variations in population densities, were greater than the differences produced by the temperature manipulation experiments at any one site in any year. (4) Infrequent extreme climatic events strongly influence long-term trends in population density and community composition. (5) The population response of invertebrates to climate warming is greatest and most rapid at the coldest sites. (6) The spatial distribution of the above ground insect herbivores on their host plant is temperature limited. (7) The numerical abundance of flying predators/parasitoids of the above-ground herbivores is low. (8) The spatial distribution of some predators may be thermally restricted and less extensive than that of their prey. (9) Habitat temperature is the driving variable determining the flight activity patterns of insects. (10) Increased summer temperatures may alter or disrupt the seasonal patterns of insect emergence, particularly in species where the life cycle is cued into the seasonal rhythm. (11) The common species of arctic soil mites and Collembola are well adapted to survive enhanced summer temperatures, providing that moisture is not limited. (12) Water availability during the summer growing period is probably of greater significance than temperature in determining the survival and success of many arctic soil invertebrate groups. (13) Arctic soil microarthropod species are well adapted to survive and operate at subzero and low positive summer temperatures. (14) Freeze-thaw events represent critical points in the life history of the microarthropods. (15) Supercooling points are sometimes poor indicators of the capacity of arctic soil microarthopods to survive low temperatures. From these findings predictions are made as to how high arctic communities will respond to predicted changes in climate.

Voltinism and Host Plant Use by Nezara viridula (L.) (Hemiptera: Pentatomidae) in Southeastern Queensland

ABSTRACTAspects of the ecology of Nezara viridula were studied in soybean‐growing areas of southeastern Queensland, Australia. Trends in population density, the number of generations, and the sequence of host plants used were investigated. Two principal generations were completed in a season, as shown by a bimodal occurrence of egg masses, nymphs and reproductively immature adult females. Nymphs were numerous relative to adults during two periods, once between late spring and early summer (mainly on wild crucifers: Rapistrum rugosum (L.) All. and Raphanus raphanistrum L.) and again in early autumn (on pod‐filling soybean). This pattern was consistent across study sites. Between midsummer and late summer, population densities were extremely low and most bugs were in the adult stage. the adult bugs were found on several host plant species, including Medicago sativa L., Datura ferox L., D. stromonium L., Ricinus communis L., Zea mays L., Sorghum bicolor (L.) Moench, Macroptilium lathyroides (L.) Urb. and Physalis virginiana L. Possible explanations for the low number of generations completed during the 8 months that the bugs were not in diapause and for low bug numbers during the summer months are evaluated. We suggest that host plant availability and suitability were the major factors contributing to the observed patterns in the population dynamics of N. viridula and that egg parasitism was not important.

最近の温室効果ガス排出見通しとそれによる気候変動について

We reviewed recent global emission scenarios on greenhouse gases, and analyzed their driving forces. As for scenarios on anthropogenic carbon dioxide emission from energy consumption, we compared their characteristics with global historical trends from the points of economic value added, energy per value added and carbon emissionsper energy. Also scenarios on carbon release from land-use change were compared with the historical trends of population density and consequent deforestation in tropical Asia. With aggregate climate and sea level rise models, the climatic implication of their GHG emission scenarios was disclosed and their uncertainty was discussed.