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At least 307 records · Page 17Linked to original sources
PubMed2002

Resistant sorption of in situ chlorobenzenes and a polychlorinated biphenyl in river Rhine suspended matter.

The desorption kinetics of in situ chlorobenzenes (dichlorobenzenes, pentachlorobenzene and hexachlorobenzene) and 2,4,4'-trichlorobiphenyl (PCB-28) were measured with a gas-purge technique for river Rhine suspended matter sampled in Lobith, The Netherlands. This suspended matter is the main source of sediment accumulation in lake Ketelmeer. In lake Ketelmeer sediment earlier observations showed that slow and very slow fractions dominate the desorption profile. For the river Rhine suspended matter, only for PCB-28 a fast desorbing fraction of around 1.6% could be detected. The observed rate constants were on the average 0.2 h(-1) for fast desorption, 0.004 h(-1) for slow desorption, and 0.00022 h(-1) for very slow desorption. These values are in agreement with previous findings for the sediment from lake Ketelmeer and with available literature data on fast, slow, and very slow desorption kinetics. The results from this study show the similarity of desorption profiles between river Rhine suspended matter, and the top layer sediment from lake Ketelmeer. This indicates that slow and very slow fractions are already present in material forming the top layer of lake Ketelmeer, and were not formed after deposition of this material in the lake. The absence of detectable fast fractions for most compounds could be caused by the absence of recent pollution of the suspended matter. But, the observations may also be explained by a rapid disappearance of compounds from the fast fraction due to a combination of a high affinity of very slow sites for these compounds, and their relatively high volatility.

Adsorption↗
PubMed1983

Histopathological changes in selenium-exposed fish.

Redear sunfish (Lepomis microlophus) were collected from Martin Lake in east Texas. For at least 8 months, 1 year earlier, aqueous selenium-laden effluent from man-made sources was released into this 5,000-acre reservoir (unpublished data). Redear sunfish from a reference lake, 8 km upstream, were collected for comparison to Martin Lake fish. The hepatopancreas (i.e., liver and associated, disseminated exocrine pancrease), mesonephros (i.e., kidney), gonads, heart, spleen, stomach, and gill arches were preserved for histopathological examination using optical and/or transmission electron microscopy. Livers from Martin Lake redear sunfish (which had accumulated approximately 20 ppm selenium in the liver) showed central necrosis, reduced quantities of rough endoplasmic reticulum and glycogen particles, and increased numbers of lysosome-like structures. Kidneys showed proliferative glomerulonephritis, and exocrine pancreas showed marked hypertrophy at the optical level. Ultrastructurally, architectural disorganization, reduced rough endoplasmic reticulum, increased cisternal space, and proliferation of smooth endoplasmic reticulum were evident. The stomach, spleen, gill, heart, and gonads showed no abnormalities.

Animals↗
PubMed2002

[Evaluation on the impacts of environmental changes and Three-Gorge engineering on the population of Yangtze voles (Microtus forits) in the Dongting Lake region].

The relationships between the population of Yangtze voles (Microtus fortis) and the evolvement of the Dongting Lake beaches were analyzed based on historical data, and the impacts of the Three-Gorge Engineering on beach environment and water level of the lake were assessed according to the regulation scheme on downward discharge flux of the Three-Gorge dam. The results indicated that the population of the voles has been increasing since 1950's, owing to the continuous enlargement of the lake beach and prolonging successional emergence of the beach. The emergence date of the beach in Autumn would be earlier, its emergence area would be going up, the population of the voles would be also expanded at the initial post-construction stage, which would still increase with the continuous expansion of beach area in a middle and long period after the establishment of the dam. More voles would thus move to the farmland, and heavily harm crops.

Animals↗
PubMed2005

Mercury concentrations of fish, river water, and sediment in the Río Ramis-Lake Titicaca watershed, Peru.

This study reports the first set of data on the concentration of mercury in muscle tissue of several varieties of fish from Lake Titicaca, including the pejerrey (Basilichthyes bonariensis), the carachi (Orestias), and 2 types of indigenous catfish (Trichomycterus). Approximately 27% of the pejerrey and 75% of the carachi exceeded the US EPA fish tissue-based water quality criterion level of 0.30 microg g(-1). Mercury levels of pejerrey increased with fish size, although this relationship was less apparent for the smaller carachi. The pejerrey and carachi are important food fish for local residents. A synoptic sampling of the Río Ramis--the largest tributary to Lake Titicaca--was conducted in an attempt to determine if mercury releases from artisanal gold mining could be an important source of Hg contamination to Lake Titicaca. Although highly elevated concentrations of Hg and other heavy metals were documented in headwater streams near the mining centers of La Rinconada and Cecilia, the quantity of Hg entering Lake Titicaca that could be attributed to mining in the Ramis watershed was below the quantifiable limit in our July 2002 study. This does not diminish the localized threat to mercury exposure for the artisanal gold miners themselves, as well as their families. Further studies of mercury dynamics in Lake Titicaca are recommended, as well as in the rivers draining into the lake. It is probable that most of the downgradient transport of Hg and other trace metals from the headwater mining centers occurs as suspended sediment during seasonal periods of high-flow.

Animals↗
PubMed1995

Sacroiliac kinematics for reciprocal straddle positions.

STUDY DESIGN: A descriptive and correlation approach was used to assess joint motion. OBJECTIVES: Magnitudes and directions of sacroiliac motion were examined from three different upright postural conditions. SUMMARY OF BACKGROUND DATA: Evidence and clinical views suggest that sacroiliac motion available in the normal case is extremely small to nonexistent. METHODS: Systems for standardizing the three postures and the Metrecom skeletal analysis system (Metrecom, Faro Technologies, Inc., Lake Mary, FL) for acquiring coordinate data for selected skeletal landmarks. RESULTS: The complete sacroiliac oblique-sagittal motion that occurred between the right forward and left forward stride positions was 9 degrees (SD 6.5). The composite oblique-transverse motion was 5 degrees (SD 3.9). The motions in each plane were significantly different from zero. A joint mobility relationship existed between the hip and sacroiliac joints. CONCLUSION: The results demonstrate that substantial angular motion is possible at the sacroiliac joints.

Adult↗
PubMed1975

Baseline concentrations of polychlorinated biphenyls and DDT in Lake Michigan fish, 1971.

Responding to the recommendations of the Lake Michigan Interstate Pesticide Committee, the author aimed to establish baseline baseline data on polychlorinated biphenyls (PCB's) and DDT in Lake Michigan fish in 1971. Because the past 2 years had witnessed unprecedented legislative action to protect food resources and other aquatic species near the top of the food chain from persistent hazardous chemicals, the author also attempted to gauge the impact of cooperative legislative action on the quality of large lakes. Thirteen species of fish taken from 14 regions of Lake Michigan in the fall of 1971 were analyzed for PCB's and DDT analogs. Mean wet-weight concentrations of PCB's similar to Aroclor 1254 ranged from 2.7 ppm in rainbow smelt to 15 ppm in lake trout. Most trout and salmon longer than 12 inches contained PCB's at concentrations greater than the tolerance level of 5 ppm established by the Food and Drug Administration, U.S. Department of Health, Education, and Welfare. Mean concentrations of total DDT ranged from less than 1 ppm in suckers to approximately 16 ppm in large lake trout. The presence of the major chlorinated hydrocarbons was confirmed by gas-liquid chromatography/mass spectrometry; additional PCB confirmations were obtained through perchlorination. The most abundant PCB's were tetra, penta-, hexa-, and hepatchlorobiphenyls which are similar to commercially prepared Aroclor 1254; lesser chlorinated PCB's were present in fish from nearshore waters.

Animals↗
PubMedDate not supplied

Toxicological response and its reversibility in rats fed Lake Ontario or Pacific coho salmon for 13 weeks.

Lake Ontario coho salmon were known to contain a mixture of chemical contaminants. A previous study demonstrated that rats fed the Lake Ontario fish-supplemented diet for 28 days exhibited mild biochemical and histological changes. The purpose of the present study was to determine the effects due to a longer term of exposure and the reversibility of these effects. Growth rate and food consumption were not affected by feeding the animals with Lake Ontario or Pacific fish-supplemented diets for 13 weeks. No deaths were observed. Decreased spleen weights were observed in groups of males fed 1.45%, 5.8% Lake Ontario and 2.9% Pacific diet. After a 13 week recovery the spleen weights returned to normal. Decreased serum potassium was observed in male rats fed 2.9% Lake Ontario diet, and all levels of Pacific diet for 13 weeks, and was not evident following maintenance on normal diet. Serum glucose was not affected by the 13-week period of treatment, however; a reduction in this parameter occurred in male rats fed the two highest doses of Lake Ontario diet and all doses of Pacific diet following the 13-week recovery period. Minor hematological changes occurred only in the male rats fed either Lake Ontario or Pacific diet following a 13 week recovery period and included reduced marrow myeloid cells and myeloid/erythroid ratio. Hepatic microsomal ethoxyresorufin deethylase activity was significantly increased in rats ingesting Lake Ontario diet. Mild histological changes occurred in the liver and thyroid of the treated males, and in the liver and kidney of the treated females. These changes were attributed to the chemical residues and/or the fish diet. Data presented here indicated that the Lake Ontario fish-supplemented diet can cause mild biochemical, hematological and histological changes but most of these were reversible when exposure was terminated.

Animals↗
PubMed2005

Patterns of Hg bioaccumulation and transfer in aquatic food webs across multi-lake studies in the northeast US.

The northeastern USA receives some of the highest levels of atmospheric mercury deposition of any region in North America. Moreover, fish from many lakes in this region carry Hg burdens that present health risks to both human and wildlife consumers. The overarching goal of this study was to identify the attributes of lakes in this region that are most likely associated with high Hg burdens in fish. To accomplish this, we compared data collected in four separate multi-lake studies. Correlations among Hg in fish (4 studies) or in zooplankton and fish (2 studies) and numerous chemical, physical, land use, and ecological variables were compared across more than 150 lakes. The analysis produced three general findings. First, the most important predictors of Hg burdens in fish were similar among datasets. As found in past studies, key chemical covariates (e.g., pH, acid neutralizing capacity, and SO4) were negatively correlated with Hg bioaccumulation in the biota. However, negative correlations with several parameters that have not been previously identified (e.g., human land use variables and zooplankton density) were also found to be equally important predictors. Second, certain predictors were unique to individual datasets and differences in lake population characteristics, sampling protocols, and fish species in each study likely explained some of the contrasting results that we found in the analyses. Third, lakes with high rates of Hg bioaccumulation and trophic transfer have low pH and low productivity with relatively undisturbed watersheds suggesting that atmospheric deposition of Hg is the dominant or sole source of input. This study highlights several fundamental complexities when comparing datasets over different environmental conditions but also underscores the utility of such comparisons for revealing key drivers of Hg trophic transfer among different types of lakes.

Animals↗
PubMed2005

Distribution of typical freshwater bacterial groups is associated with pH, temperature, and lake water retention time.

The distribution of 15 typical freshwater bacterial groups in 15 diverse lakes in northern Europe was investigated using reverse line blot hybridization. Statistical evaluation of the data in relation to the characteristics of the lakes showed that pH, temperature, and the theoretical hydrological retention time of the lakes were most strongly related to variations in the distribution of bacterial taxa. This suggests that pH and temperature are steering factors in the selection of taxa and supports the notion that communities in lakes with short water turnover times are influenced by the input of bacterial cells from the drainage areas. Within the beta subdivision of the Proteobacteria (Betaproteobacteria), as well as within the divisions Actinobacteria and Verrucomicrobia, different subgroups were associated differently with environmental variables.

Animals↗
PubMed2005

Saline systems of the Great Plains of western Canada: an overview of the limnogeology and paleolimnology.

In much of the northern Great Plains, saline and hypersaline lacustrine brines are the only surface waters present. As a group, the lakes of this region are unique: there is no other area in the world that can match the concentration and diversity of saline lake environments exhibited in the prairie region of Canada and northern United States. The immense number of individual salt lakes and saline wetlands in this region of North America is staggering. Estimates vary from about one million to greater than 10 million, with densities in some areas being as high as 120 lakes/km2. Despite over a century of scientific investigation of these salt lakes, we have only in the last twenty years advanced far enough to appreciate the wide spectrum of lake types, water chemistries, and limnological processes that are operating in the modern settings. Hydrochemical data are available for about 800 of the lake brines in the region. Composition, textural, and geochemical information on the modern bottom sediments has been collected for just over 150 of these lakes. Characterization of the biological and ecological features of these lakes is based on even fewer investigations, and the stratigraphic records of only twenty basins have been examined. The lake waters show a considerable range in ionic composition and concentration. Early investigators, concentrating on the most saline brines, emphasized a strong predominance of Na+ and SO4-2 in the lakes. It is now realized, however, that not only is there a complete spectrum of salinities from less than 1 ppt TDS to nearly 400 ppt, but also virtually every water chemistry type is represented in lakes of the region. With such a vast array of compositions, it is difficult to generalize. Nonetheless, the paucity of Cl-rich lakes makes the northern Great Plains basins somewhat unusual compared with salt lakes in many other areas of the world (e.g., Australia, western United States). Compilations of the lake water chemistries show distinct spatial trends and regional variations controlled by groundwater input, climate, and geomorphology. Short-term temporal variations in the brine composition, which can have significant effects on the composition of the modern sediments, have also been well documented in several individual basins. From a sedimentological and mineralogical perspective, the wide range of water chemistries exhibited by the lakes leads to an unusually large diversity of modern sediment composition. Over 40 species of endogenic precipitates and authigenic minerals have been identified in the lacustrine sediments. The most common non-detrital components of the modern sediments include: calcium and calcium-magnesium carbonates (magnesian calcite, aragonite, dolomite), and sodium, magnesium, and sodium-magnesium sulfates (mirabilite, thenardite, bloedite, epsomite). Many of the basins whose brines have very high Mg/Ca ratios also have hydromagnesite, magnesite, and nesquehonite. Unlike salt lakes in many other areas of the world, halite, gypsum, and calcite are relatively rare endogenic precipitates in the Great Plains lakes. The detrital fraction of the lacustrine sediments is normally dominated by clay minerals, carbonate minerals, quartz, and feldspars.Sediment accumulation in these salt lakes is controlled and modified by a wide variety of physical, chemical, and biological processes. Although the details of these modern sedimentary processes can be exceedingly complex and difficult to discuss in isolation, in broad terms, the processes operating in the salt lakes of the Great Plains are ultimately controlled by three basic factors or conditions of the basin: (a) basin morphology; (b) basin hydrology; and (c) water salinity and composition. Combinations of these parameters interact to control nearly all aspects of modern sedimentation in these salt lakes and give rise to four 'end member' types of modern saline lacustrine settings in the Great Plains: (a) clastics-dominated playas; (b) salt-dominated playas; (c) deep water, non-stratified lakes; and (d) deep water, "permanently" stratified lakes.

Journal Article↗
PubMed2025

Recent rapid radiation of apex predators suggests dramatic biodiversity turnover in an ancient lake.

Top predators have oversized influence on food webs and ecosystem dynamics, and introducing a novel predator to a naive environment can have dramatic consequences for endemic biodiversity. Using genomic data, we find that the colonization of Lake Tanganyika by Lates fishes-the top predators in this ancient lake-occurred more recently than other diverse clades within the lake. Diversification into four endemic Lates species occurred within the lake during a time of dramatic changes in lake levels driven by glacial-interglacial cycles, supporting the hypothesis that these fluctuations were a "species pump" for lacustrine taxa. These lake level fluctuations also likely contributed to multiple admixture events among Lates species during the Pleistocene (~90-500 Kya). Together, our findings suggest a dynamic and environmentally-linked evolutionary history of this predator radiation, and that their colonization of the lake and subsequent diversification likely had dramatic ecosystem consequences for taxa already present in Lake Tanganyika.

Journal Article↗
PubMed2001

Detection of water quality using simulated satellite data and semi-empirical algorithms in Finland.

The aim of the study was to test the feasibility of the band combination of the TERRA MODIS and ENVISAT MERIS instruments for operational monitoring of lakes and coastal waters in Finland. Also simulated LANDSAT TM data were tested. Satellite bands were simulated using airborne measurements with AISA imaging spectrometer. Semi-empirical algorithms with simulated satellite data were tested against field observations using regression analysis. Interpretation of chlorophyll a, suspended matter, turbidity and secchi-disk depth was included in the analyses. The data for this study were gathered in campaigns carried out in May and August 1997 and August 1998 both for lakes in southern Finland and coastal waters of the Baltic Sea. The data set included 85 in situ observations for lakes and 107 for coastal waters. Our results show that the band combination to be included in the ENVISAT MERIS instrument enables the interpretation of water quality, including chlorophyll a concentration using semi-empirical algorithms both for lakes and coastal waters. MERIS band 9 centred at 705 nm is proven to be of vital importance for the detection of chlorophyll a in local surface waters.

Algorithms↗
PubMedDate not supplied

Higher venous bicarbonate concentration associated with hypoxemia, not acute mountain sickness, after ascent to moderate altitude.

BACKGROUND: The pathophysiology underlying acute mountain sickness (AMS) and excessive hypoxemia at high altitudes is not fully understood. Previous work by our group has demonstrated a significant association between urinary measures of dehydration and bicarbonate retention in subjects developing excessive hypoxemia and AMS at high altitudes. To further characterize these findings, we returned to our original testing site to examine the hypothesis that subjects with lower levels of oxygen saturation and/or AMS would possess higher levels of venous bicarbonate. METHODS: Medical history inquiry, clinical examination, Lake Louise scoring, and the collection of venous levels of bicarbonate concentration and base excess were performed on 52 lowland-dwelling persons after they completed a religious pilgrimage in the Nepal Himalayas to approximately 4,250 m. RESULTS: Oxygen saturation levels were strongly and inversely correlated with serum levels of venous bicarbonate and base excess, whereas AMS and Lake Louise scores were not associated with these measures of alkalosis. CONCLUSIONS: Our data suggest an association between measures of serum bicarbonate anion retention and decreasing oxygen saturation. Our data do not demonstrate an association between AMS or Lake Louise scores and measures of serum bicarbonate level. We propose that excessive hypoxemia at high altitudes may be associated with a compromised ability of the kidney to metabolically compensate for an altitude-induced hypocapnic alkalosis.

Adult↗
PubMed2005

Diversity and distribution of sulfate-reducing bacteria in permanently frozen Lake Fryxell, McMurdo Dry Valleys, Antarctica.

The permanently frozen freshwater Lake Fryxell, located in the Dry Valleys of Antarctica, exhibits an ideal geochemistry for microbial sulfate reduction. To investigate the population of sulfate-reducing bacteria in Lake Fryxell, both 16S rRNA gene and metabolic primer sets targeting the dsrA gene for the dissimilatory sulfite reductase alpha subunit were employed to analyze environmental DNA obtained from the water column and sediments of Lake Fryxell. In addition, enrichment cultures of sulfate-reducing bacteria established at 4 degrees C from Lake Fryxell water were also screened using the dsrA primer set. The sequence information obtained showed that a diverse group of sulfate-reducing prokaryotes of the domain Bacteria inhabit Lake Fryxell. With one exception, the enrichment culture sequences were not represented within the environmental sequences. Sequence data were compared with the geochemical profile of Lake Fryxell to identify possible connections between the diversity of sulfate-reducing bacteria and limnological conditions. Several clone groups were highly localized with respect to lake depth and, therefore, experienced specific physiochemical conditions. However, all sulfate-reducing bacteria inhabiting Lake Fryxell must function under the constantly cold conditions characteristic of this extreme environment.

Antarctic Regions↗
PubMed2004

The structure of variation and its influence on the estimation of status: indicators of condition of lakes in the Northeast, U.S.A.

One goal of regional-scale sample surveys is to estimate the status of a resource of interest from a statistically drawn representative sample of that resource. An expression of status is the frequency distribution of indicator scores capturing variability of attributes of interest. However, extraneous variability interferes with the status description by introducing bias into the frequency distributions. To examine this issue, we used data from a regional survey of lakes in the Northeast U.S. collected by the U.S. Environmental Protection Agency's Environmental Monitoring and Assessment Program (EMAP). We employ a components of variance model to identify sources of extraneous variance pertinent to status descriptions of physical, chemical, and biological attributes of the population of lakes in the NE. We summarize the relative magnitude of four components of variance (lake-to-lake, year, interaction, and residual) for each indicator and illustrate how extraneous variance biases the status descriptions. We describe a procedure that removes this bias from the status descriptions to produce unbiased estimates and introduce a novel method for estimating the 'cost' of removing the bias (expressed as either increased sampling uncertainty or additional samples needed to achieve the target precision in the absence of bias). We compare the relative magnitude of the four variance components across the array of indicators, finding in general that conservative chemical indicators are least affected by extraneous variance, followed by some nonconservative indicators, with nutrient indicators most affected by extraneous variance. Intermediate were trophic condition indicators (including sediment diatoms), fish species richness and individuals indicators, and zooplankton taxa richness and individuals indicators. We found no clear patterns in the relative magnitude of variance components as a function of several methods of aggregating fish and zooplankton indicators (e.g., level of taxonomy, or species richness vs. numbers of individuals).

Analysis of Variance↗
PubMed2002

Patterns in fish radiation are compatible with Pleistocene desiccation of Lake Victoria and 14,600 year history for its cichlid species flock.

Geophysical data are currently being interpreted as evidence for a late Pleistocene desiccation of Lake Victoria and its refilling 14,600 years ago. This implies that between 500 and 1000 endemic cichlid fish species must have evolved in 14,600 years, the fastest large-scale species radiation known. A recent review concludes that biological evidence clearly rejects the postulated Pleistocene desiccation of the lake: a 14,600 year history would imply exceptionally high speciation rates across a range of unrelated fish taxa. To test this suggestion, I calculated speciation rates for all 41 phylogenetic lineages of fish in the lake. Except for one cichlid lineage, accepting a 14 600 year history does not require any speciation rates that fall outside the range observed in fishes in other young lakes around the world. The exceptional taxon is a lineage of haplochromine cichlids that is also known for its rapid speciation elsewhere. Moreover, since it is unknown how many founding species it has, it is not certain that its speciation rates are really outside the range observed in fishes in other young lakes. Fish speciation rates are generally faster in younger than in older lakes, and those in Lake Victoria, by far the largest of the young lakes of the world, are no exception. From the speciation rates and from biogeographical observations that Lake Victoria endemics, which lack close relatives within the lake basin, have such relatives in adjacent drainage systems that may have had Holocene connections to Lake Victoria, I conclude that the composition of the fish assemblage does not provide biological evidence against Pleistocene desiccation. It supports a hypothesis of recent colonization from outside the lake basin rather than survival of a diverse assemblage within the basin.

Africa, Eastern↗
PubMed2005

[Changes of land use and landscape pattern in Taihu Lake Basin].

Based on three sets of land use data (1985, 1995 and 2000), and by means of the techniques of remote sensing, geographical information system (GIS), and landscape ecology, this paper studied the changes of land use and landscape pattern from 1985 to 2000 in Taihu Lake Basin located at Yangtse River Delta. The results showed that in past 15 years, the farmland in this Basin decreased, while the built-up areas, woodland, grassland and water body increased. The decrease of the farmland occupied 89.64% of total decrement, while the increase of the built-up areas accounted for 79.21% of total increment. Under the disturbance of human activities, the landscape structure and landscape heterogeneity in Taihu Lake Basin changed greatly. The patches density decreased from 0.996 to 0.930, diversity indices decreased from 1.127 to 1.113, evenness indices decreased from 62.891% to 62.109%; while the edge density increased from 4.408 to 4.459, dominance indices increased from 0.665 to 0.679, and shape indices increased from 1.540 to 2.796. The landscape heterogeneity varied with different kinds of landscape, indicating the complexity of landscape ecosystem. In all kinds of landscapes, farmland and grassland had the highest values of diversity indices. The diversity indices of water bodies decreased firstly and then increased, while those of built-up areas were in adverse. The evenness index was decreased in the order of woodland > farmland > grassland > water body > built-up areas. Population, economy and policies were the driving forces of the dynamic changes of landscape pattern in Lake Taihu Basin during past 15 years, and land use change in the Basin caused distinct landscape effects, such as landscape fragmenting, edge effects intensification, and environmental quality declining. The mode of land use should be adjusted in landscape scale to rehabilitate and reconstruct the landscape ecosystems in Taihu Lake Basin.

Agriculture↗
PubMed2002

[Correlation between monthly average temperature and grasshopper outbreak in the region around Qinghai Lake based on GIS].

It is necessary to study the relationship between grasshopper and ecological factors for forecasting grasshopper outbreak effectively. Temperature is one of main factors influencing grasshopper outbreak in the region around Qinghai Lake. With the support of Arc/Info and ArcView, monthly average temperatures were simulated under the scale of 150 m by data from sixteen meteorological stations adjacent to Qinghai Lake for adapting the comprehensive method and establishing spatial temperature database. Then, the relationship between grasshopper outbreak and monthly average temperature were analyzed by combining the spatial data of grasshopper density and the spatial data of monthly average temperature. The result showed that effects of monthly average temperature on Grasshopper outbreak were closely related to the life cycle of the dominant grasshopper species in the region, namely, monthly average temperatures of May, June, and July influenced grasshopper outbreak in the current year, and monthly average temperatures of August and September influenced grasshopper outbreak in the next year. Thereby, it could provide a base of establishing forecasting models of grasshopper outbreak.

Animals↗