Resource patch array use by two squirrel species in an agricultural landscape     

Fisher  Jason T.  Merriam  Gray 《Landscape Ecology》2000,15(4):333-338

Eastern grey squirrels (Sciurus carolinensis) and North American red squirrels (Tamiasciurus hudsonicus) were studied among wooded patches within an agricultural mosaic. Fifteen sites south of Ottawa, Canada, with differing landscape and local features were censused using tracking boards placed in a woods or wooded fencerow. Regression analyses of landscape compositional and physiognomic variables within a 1-km radius isolated the best predictors of grey and red squirrel abundance and activity. Grey squirrels were found in both small woods and fencerows in farm landscapes but were not found in large woods. A polynomial regression of wooded patch size explained 79% of the variance in grey squirrel abundance. Grey squirrel activity was correlated with the percent cover of soybeans in the landscape. Red squirrels were found in fencerows, small and large woods; activity was correlated with the percent cover of both woods and corn crop in the surrounding landscape. These results indicate that distributions of both species are influenced by multiple landscape elements, but that grey squirrels may rely on fragmented agricultural landscapes whereas red squirrels make more use of both native woodland and altered landscapes.  相似文献   

Urban carriage horses 1999--status and concerns     

Merriam JG 《Journal of the American Veterinary Medical Association》2000,216(8):1261-1262

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MEANING OF THE SPANISH WORD GAVILAN     

Merriam CH 《Science (New York, N.Y.)》1908,28(709):147

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SOME LITTLE-KNOWN BASKET MATERIALS     

Merriam CH 《Science (New York, N.Y.)》1903,17(438):826-827

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GRIZZLY BEARS: SKULLS WANTED     

Merriam CH 《Science (New York, N.Y.)》1914,39(1003):424-426

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ZONE TEMPERATURES     

Merriam CH 《Science (New York, N.Y.)》1899,9(212):116-117

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Sources and inheritance of resistance to stemphylium leaf spot of lettuce     

D. Netzer  D. Globerson  CH. Weintal  R. Elyassi 《Euphytica》1985,34(2):393-396

Summary None of the tested cultivars of lettuce was found resistant to Stemphylium leaf spot, a common disease in Israel. Within a Lactuca saligna population collected in wild lettuce in Israel, resistance was traced. Interspecific crosses of L. saligna x L. sativa were made and the mode of inheritance of resistance to this disease was studied. Resistance is apparently controlled by two genes: one dominant (Sm₁) and one recessive (sm₂).Contribution No. 1176-E 1984 series, from the ARO.  相似文献   

Simulating carbon dynamics of the boreal forest in Pukaskwa National Park     

I. A. Nalder  H. G. Merriam 《Water, air, and soil pollution》1995,82(1-2):283-298

The development of forests in Pukaskwa National Park, Ontario, Canada, was simulated over 150 years to investigate boreal carbon dynamics and to test the feasibility of simulating large tracts of heterogeneous boreal forest. Pukaskwa National Park, located on the north shore of Lake Superior, encompasses 1835 km² of the Superior Section of the boreal forest. We developed a patch model, called BOPAS (BOreal PAtch Simulator), to simulate the development of carbon pools as a function of environmental parameters. Using GIS techniques, we divided the park into patches defined by a unique combination of forest type, age, climatic variables, soil type and topography, then used a forest gap model to develop biomass-over-time relationships for each patch type. BOPAS uses these relationships to simulate the development of carbon pools for trees, moss and litter/humus. We report results for constant climate, but BOPAS can be easily adapted to changing climate scenarios. Good results were obtained for predictions of carbon storage in trees. The initial value was 3.61 kg C m^?2, which agrees closely with literature values. With no disturbance, tree carbon increased to a maximum of 3.97 kg C m^?2 at 30 years then slowly declined. Carbon storage was stabilized by introducing fire as a disturbance with a return interval of 100 years. Predicted forest floor carbon density, however, was much lower than expected, being less than half that of trees. It was anticipated to be substantially higher than tree carbon density based on a preliminary survey in the park and values reported in the literature. Published data, however, are very limited in coverage and give such a wide range of values that it was impossible to draw any firm conclusions about the validity of the model. BOPAS also showed that the forest floor carbon pool was relatively constant over the timescales of the simulation, but no published data were available to test this prediction. In summary, this work has demonstrated the feasibility of the BOPAS approach, but has high-lighted the necessity for more extensive data on forest floor carbon storage and dynamics.  相似文献   

AUDUBON AND HIS JOURNALS     

Merriam CH 《Science (New York, N.Y.)》1898,7(166):289-296

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Wind generators and the oil reserve     

Merriam MF 《Science (New York, N.Y.)》1979,203(4384):954-955

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