Investigation into mountain pine beetle above-canopy dispersion using weather radar and an atmospheric dispersion model

Abstract

Above-canopy, wind-assisted mountain pine beetle (MPB) dispersion in British Columbia (BC) is examined during the summer 2005 beetle emergence period. Above-canopy dispersion is simulated by the HYSPLIT atmospheric dispersion model using back trajectories started from locations identified by clear-air returns from the Prince George BC weather radar station. The dispersion calculations are carried out over the 10 days showing the highest intensity of clear-air returns from the 2005 emergence season. The Weather Research and Forecast (WRF) model is used to simulate the meteorological conditions during each of the 10 emergence days. Cumulative clear-air returns throughout each emergence day are used to estimate the distribution of beetle emergence times and atmospheric residence times. Evaluation of the WRF model output is presented using both surface and upper air observations. Evaluation of the HYSPLIT model is performed through a comparison of the vertical distribution of MPB observed in a previous study. A secondary HYSPLIT evaluation is performed using aerial surveys taken during the following summer (2006), which identify the previous years' beetleinfested regions. Beetle flight distances from the time of beetle emergence to the time of peak clear-air returns are calculated for each trajectory, and the distribution of all flight distances is presented. The mean back trajectory distance is 20.2 km with a standard deviation of 13.6 km. These values represent the MPB flight distance during half of the beetle atmospheric residence time, and typical daily windassisted dispersion distances would be expected to be roughly double this value. Mean beetle residence time in the atmosphere over the 10 emergence events is found to be 3.2 h.

Breach of the northern Rocky Mountain geoclimatic barrier: initiation of range expansion by the mountain pine beetle

“…, 2011), and dispersal and landscape dynamics (Robertson et al. , 2009; Ainslie & Jackson, 2011; de la Giroday et al. , 2011).…”

Mountain pine beetle dispersal: spatiotemporal patterns and role in the spread and expansion of the present outbreak

“…However, dispersal and particularly LDD is the least understood aspect of mountain pine beetle population ecology , Robertson et al 2007, Jackson et al 2008. While many studies examine SDD (Gray et al 1972, Safranyik et al 1989, 1992, Robertson et al 2007, LDD, which is recognized as a potentially important component to geographic expansion of mountain pine beetle outbreaks at the landscape scale, has only recently received limited attention (Jackson et al 2008, de la Giroday 2009, Robertson et al 2009, Ainslie and Jackson 2010. Robertson et al (2007) Aukema et al (2006) studied spatiotemporal patterns and spatial synchrony of mountain pine beetle spread at the regional scale in British Columbia for two periods, incipient years 1990-1996 and epidemic years 1999-2003.…”

Perspectives and challenges for the use of radar in biological conservation

“…However, continent‐wide studies have only become possible via the use of data from WSRs. In WSRs, the focused beam of a parabolic antenna is swept azimuthally through a number of elevation angles yielding a three‐dimensional coverage of the airspace over long ranges (hundreds of km) and can provide information about the horizontal and vertical distribution of organisms (Dokter et al , 2018, Stepanian et al , Chilson et al , Drake and Bruderer ). Today, networks of WSRs span much of the terrestrial landmass in many parts of the world (Fig.…”

“…Many insects also migrate or otherwise move about the landscape at night (Chapman et al ), and most bats are exclusively nocturnal. Moreover, the vast majority of aerial species are also small (Bridge et al ), often fly at appreciable altitudes, and are transient. For example, more than a century ago, Gätke () had noted of diurnal migrants ‘that, as long as migration proceeds under its normal conditions’ its ‘elevation is, in the case of by far the larger number, so great as to be completely beyond the powers of human observation…’.…”

“…While there has been a rapid development of telemetry and other advanced tracking and data logging technologies to study the movements of individuals in detail (Stutchbury et al , Bridge et al , Kissling et al , O'Mara et al , Roeleke et al , Weller et al ), radar is still at the forefront with regards to comprehensiveness and the spatial and temporal extent of its applicability to aeroecological research on bats, birds and insects. Furthermore, the majority of insect species, and the smallest bats and birds, currently fall below the size threshold for the application of other long‐range tracking technologies.…”