Effects of Site Thermal Variation and Physiography on Flight Synchrony and Phenology of the North American Spruce Beetle (Coleoptera: Curculionidae, Scolytinae) and Associated Species in Colorado

2019 ◽  
Vol 48 (4) ◽  
pp. 998-1011 ◽  
Author(s):  
Isaac Hans Dell ◽  
Thomas Seth Davis

AbstractSpruce beetle, Dendroctonus rufipennis Kirby, is associated with forest mortality in Colorado and across western North America, yet it is not well understood how thermal variability affects basic population processes such as flight phenology. However, phenology–temperature relationships are important for understanding patterns of ecosystem disturbance, especially under projected climate warming. Here, we use a multiyear trapping study to test the hypothesis that spruce beetle flight synchrony, timing, and fitness traits (body size) are affected by variation in regional temperature and physiography. Large quantities of co-colonizing scolytines (Polygraphus convexifrons) (Coleoptera: Curculionidae, Scolytinae) and predatory beetles (Thanasimus undulatus) (Coleoptera: Cleridae) that may affect D. rufipennis populations also responded to spruce beetle synthetic pheromone lures. Relationships between flight patterns and environmental conditions were also analyzed for these species. The winter of 2018 was warmer and drier than winter 2017 and was associated with earlier flight for both scolytine species across most sites. The most important environmental factor driving D. rufipennis flight phenology was accumulated growing degree-days, with delayed flight cessation under warmer conditions and larger beetles following a warm winter. Flight was consistently more synchronous under colder growing season conditions for all species, but synchrony was not associated with winter temperatures. Warmer-than-average years promoted earlier flight of D. rufipennis and associated species, and less synchronous, prolonged flight across the region. Consequently, climate warming may be associated with earlier and potentially extended biotic pressure for spruce trees in the Rocky Mountain region, and flight phenology of multiple scolytines is plastic in response to thermal conditions.

1959 ◽  
Vol 37 (5) ◽  
pp. 753-761 ◽  
Author(s):  
R. W. Stark

Four major air masses, tropical maritime (mT), polar maritime (mP), arctic maritime (mA), and arctic continental (cA) may be used in describing the winter climate of a lodgepole needle miner (Recurvaria starki Free.) outbreak area. The main circulation is from the north and west which results in a predominance of mP and cA air. Local topography and its effect on winter climate is described for four areas now sampled on a life-table basis. Variations in winter mortality from year to year and between sampling areas are related to climate. Extensive invasions of cA air, particularly of long duration, cause lethal winter temperatures. Winter mortality usually occurs during the coldest month, January, and may be exceptionally high when extreme minima of −30° F to −40° F persist long enough to depress the monthly mean temperature close to O° F. However, less extreme temperatures in other months may result in similar high mortalities if these are unseasonably low. The climatic conditions causing high mortality generally occur at the tops of slopes and at valley bottoms, allowing the middle slopes to serve as "refuge areas" for surviving needle miner populations.


2012 ◽  
Vol 42 (9) ◽  
pp. 1649-1660 ◽  
Author(s):  
R. Justin DeRose ◽  
James N. Long

The view that subalpine forest vegetation dynamics in western North America are “driven” by a particular disturbance type (i.e., fire) has shaped our understanding of their disturbance regimes. In the wake of a recent (1990s) landscape-extent spruce beetle ( Dendroctonus rufipennis Kirby) outbreak in the southern Rocky Mountains, we re-examined the temporal continuity in disturbance types and interactions and the possible role of drought on their occurrence by reconstructing antecedent disturbances for 11 sites across the Markagunt Plateau, southern Utah, USA. Multiple consistent lines of evidence suggested that historic fires were the primary antecedent disturbance, while relatively minor, stand-specific spruce beetle activity occurred later in stand development but prior to the recent outbreak. Unlike the recent outbreak, antecedent fires were spatially and temporally asynchronous over the period examined (~1600–2000). Reconstructed fire events primarily occurred during periods of prolonged drought. Similarly, historic spruce beetle activity, indicated by species-specific tree-ring release, and timing of Engelmann spruce ( Picea engelmannii Parry ex Engelm.) death dates from the recent outbreak were related to drought conditions. Vegetation dynamics on this landscape were strongly driven by historic fires and the recent spruce beetle outbreak, and drought conditions likely influenced the occurrence of both disturbance types.


1996 ◽  
Vol 46 (3) ◽  
pp. 311-318 ◽  
Author(s):  
Scott A. Elias

Mutual Climatic Range (MCR) analysis was applied to 20 fossil beetle assemblages from 11 sites dating from 14,500 to 400 yr B.P. The fossil sites represent a transect of the Rocky Mountain region from northern Montana to central Colorado. The analyses yielded estimates of mean July and mean January temperatures. The oldest assemblage (14,500 yr B.P.) yielded mean July values of 10–11°C colder than present and mean January values 26–30°C colder than present. Postglacial summer warming was rapid, as indicated by an assemblage dating 13,200 yr B.P., with mean July values only 3–4°C cooler than modern. By 10,000 yr B.P., several assemblages indicate warmer-than-modern mean summer and winter values. By 9000 yr B.P., MCR reconstructions indicate that both summer and winter temperatures were already declining from an early Holocene peak. Mean July values remained above modern levels and mean January values remained below modern levels until 3000 yr B.P. A series of small-scale oscillations followed.


1986 ◽  
Vol 64 (3) ◽  
pp. 541-551 ◽  
Author(s):  
George W. Argus

A study of morphological variation in the Salix lucida complex revealed three geographical races: one in northeastern North America, a second in western North America extending from Alaska to California, and a third in the southern Rocky Mountains, S. lucida ssp. lucida, Salix lucida ssp. lasiandra comb, nov., and Salix lucida ssp. caudata comb, nov., respectively. The Salix reticulata complex in the Rocky Mountain region is represented by two geographical races, ssp. reticulata in the north and ssp. nivalis in the south. Variation in ssp. nivalis suggests that hybridization and introgression occur where the two races overlap, and that the results of past hybridization are still evident in the southern Rocky Mountains.


2003 ◽  
Vol 33 (9) ◽  
pp. 1815-1820 ◽  
Author(s):  
Diana L Six ◽  
Barbara J Bentz

Fungi were isolated from individual Dendroctonus rufipennis (Kirby) collected from six populations in Alaska, Colorado, Utah, and Minnesota, U.S.A. In all populations, Leptographium abietinum (Peck) Wingfield was the most commonly isolated mycelial fungus (91–100% of beetles). All beetles in all populations were associated with yeasts and some with only yeasts (0–5%). In one population, Ophiostoma ips (Rumbold) Nannf. was also present on 5% of the beetles but always in combination with L. abietinum and yeasts. Ophiostoma piceae (Munch) H. & P. Sydow was found on 2% of beetles in another population. Ceratocystis rufipenni Wingfield, Harrington & Solheim, previously reported as an associate of D. rufipennis, was not isolated from beetles in this study. Ceratocystis rufipenni is a virulent pathogen of host Picea, which has led to speculation that C. rufipenni aids the beetle in overcoming tree defenses and therefore contributes positively to the overall success of the beetle during colonization. However, our results, considered along with those of others, indicate that C. rufipenni may be absent from many populations of D. rufipennis and may be relatively rare in those populations in which it is found. If this is true, C. rufipenni may be only a minor or incidental associate of D. rufipennis and, as such, not likely to have significant impacts on beetle success or population dynamics. Alternatively, the rarity of C. rufipenni in our and others isolations may be due to difficulties in isolating this fungus in the presence of other faster growing fungi such as L. abietinum.


2008 ◽  
Author(s):  
Kelly S. Burns ◽  
Anna W. Schoettle ◽  
William R. Jacobi ◽  
Mary F. Mahalovich

Water ◽  
2021 ◽  
Vol 13 (6) ◽  
pp. 866
Author(s):  
Gary Free ◽  
Mariano Bresciani ◽  
Monica Pinardi ◽  
Nicola Ghirardi ◽  
Giulia Luciani ◽  
...  

Climate change has increased the temperature and altered the mixing regime of high-value lakes in the subalpine region of Northern Italy. Remote sensing of chlorophyll-a can help provide a time series to allow an assessment of the ecological implications of this. Non-parametric multiplicative regression (NPMR) was used to visualize and understand the changes that have occurred between 2003–2018 in Lakes Garda, Como, Iseo, and Maggiore. In all four deep subalpine lakes, there has been a disruption from a traditional pattern of a significant spring chlorophyll-a peak followed by a clear water phase and summer/autumn peaks. This was replaced after 2010–2012, with lower spring peaks and a tendency for annual maxima to occur in summer. There was a tendency for this switch to be interspersed by a two-year period of low chlorophyll-a. Variables that were significant in NPMR included time, air temperature, total phosphorus, winter temperature, and winter values for the North Atlantic Oscillation. The change from spring to summer chlorophyll-a maxima, relatively sudden in an ecological context, could be interpreted as a regime shift. The cause was probably cascading effects from increased winter temperatures, reduced winter mixing, and altered nutrient dynamics. Future trends will depend on climate change and inter-decadal climate drivers.


Sign in / Sign up

Export Citation Format

Share Document