Population trends and interactions among terns and gulls in Gros Morne National Park, Newfoundland

1993 ◽  
Vol 71 (8) ◽  
pp. 1516-1520 ◽  
Author(s):  
Lesley-Anne Howes ◽  
William A. Montevecchi
Keyword(s):  
North America ◽  
National Park ◽  
Management Strategies ◽  
Population Trends ◽  
Eastern North America ◽  
Sterna Hirundo ◽  
Local Production ◽  
Common Terns

Although populations of Common Terns and Arctic Terns (Sterna hirundo, S. paradisaea) have been decreasing and gull (Larus spp.) populations have been increasing in eastern North America for more than 50 years, little is known about the population trends of these species in Newfoundland. Here we present data, spanning two decades, on the population trends and interactions of terns and gulls on five islands in Gros Morne National Park in western Newfoundland. Tern populations in this region are increasing despite interactions with gulls and low productivity. Immigration from disturbed colonies elsewhere is suggested as a possible source of the increase. Gull populations have also increased substantially since the early 1970s and closely follow local production of fisheries offal, as indicated by landing trends in the area. Implications for gull management strategies are discussed.

Twenty-five year population trends in Northern Saw-whet Owl (Aegolius acadicus) in eastern North America

2021 ◽  
Vol 132 (3) ◽  
Author(s):  
Jennifer Wall ◽  
David Brinker ◽  
Scott Weidensaul ◽  
David Okines ◽  
Pascal Côté ◽  
...  
Keyword(s):  
North America ◽  
Population Trends ◽  
Eastern North America ◽  
Aegolius Acadicus

scholarly journals Stemphylium Leaf Blight: A Re-Emerging Threat to Onion Production in Eastern North America

Plant Disease ◽  
2021 ◽  
Author(s):  
Frank Hay ◽  
Sara Marie Stricker ◽  
Bruce Gossen ◽  
Mary Ruth McDonald ◽  
Daniel Heck ◽  
...  
Keyword(s):  
New York ◽  
North America ◽  
Management Strategies ◽  
Early Spring ◽  
Leaf Blight ◽  
Eastern North America ◽  
Resistance Development ◽  
Air Temperatures ◽  
Pleospora Allii ◽  
Prediction Systems

Stemphylium leaf blight (SLB), caused by Stemphylium vesicarium, is a foliar disease of onion worldwide, and has recently become an important disease in the northeastern United States and Ontario, Canada. The symptoms begin as small, tan to brown lesions on the leaves that can progress to defoliate plants. Crop loss occurs through reduced photosynthetic area, resulting in smaller, lower-quality bulbs. Leaf necrosis caused by SLB also can compromise bulb storage, as green leaves are required for the uptake of sprout inhibitors applied prior to harvest. The pathogen can overwinter on infested onion residue and infected volunteer plants. Asymptomatic weedy hosts near onion fields may also be a source of inoculum. Production of ascospores of the teleomorph (Pleospora allii) peaks in early spring in northeastern North America, often before the crop is planted, and declines rapidly as daily mean air temperatures rise. Conidia usually are present throughout the growing season. Application of fungicides is a standard practice for management of the complex of fungi that can cause foliar diseases of onion in this region. Recent assessments have shown that populations of S. vesicarium in New York and Ontario are resistant to at least three single-site mode-of-action fungicides. Three disease prediction systems have been developed and evaluated that may enable growers to reduce the frequency and/or number of fungicide applications, but the loss of efficacious fungicides due to resistance development within S. vesicarium populations threatens sustainability. The lack of commercially acceptable onion cultivars with sufficient resistance to reduce the number of fungicides for SLB also limits the ability to manage SLB effectively. Integrated disease management strategies for SLB are essential to maintain profitable, sustainable onion production across eastern North America.

PARASITOIDS OF ENDEMIC AND EPIDEMIC POPULATIONS OF CHORISTONEURA OCCIDENTALIS FREEMAN AND CHORISTONEURA RETINIANA (WALSINGHAM) (LEPIDOPTERA: TORTRICIDAE) IN SOUTHERN OREGON

1991 ◽  
Vol 123 (5) ◽  
pp. 1095-1102 ◽  
Author(s):  
Willis C. Schaupp ◽  
W. Jan A. Volney ◽  
William E. Waters
Keyword(s):  
North America ◽  
Quantitative Estimation ◽  
Host Density ◽  
Population Trends ◽  
Eastern North America ◽  
Choristoneura Occidentalis ◽  
Parasitoid Species ◽  
Choristoneura Retiniana ◽  
Parasite Complex

AbstractParasitoid species attacking sparse, endemic populations of Choristoneura occidentalis Freeman and C. retiniana (Walsingham) are reported from 2 years of host collections at seven sites across southern Oregon. Results are compared with rearings from epidemic populations either from the same region or the same plot. Collections were designed to allow quantitative estimation of host density. Most of the parasitoid species present during epidemics across North America were recovered from the endemic and epidemic populations studied. The major difference is that at endemic host densities Glypta fumiferanae (Viereck) (Ichneumonidae) is rare to absent, whereas ichneumonids of the tribe Campoplegini, especially Tranosema (= Diadegma) interruptum (Ashmead), are common. This is the reverse of the situation at epidemic densities and consistent with results reported from eastern North America. It is suggested that the observed shift in the parasite complex with budworm density has the potential for predicting population trends.

Pacific Firmoss (Huperzia miyoshiana) (Lycopodiaceae) in Eastern North America at Gros Morne National Park, Newfoundland

1992 ◽  
Vol 82 (2) ◽  
pp. 63 ◽  
Author(s):  
Daniel F. Brunton ◽  
Warren H. Wagner ◽  
Joseph M. Beitel
Keyword(s):  
North America ◽  
National Park ◽  
Eastern North America
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