Organic, elemental, and geochemical contributions to lake sediment deposits during severe spruce beetle (Dendroctonus rufipennis) disturbances

Long-term landscape changes in a subalpine spruce-fir forest in central Utah, USA

“…For example, at Blue Lake the spruce/fir ratio dropped from 0.5 to −0.5 and from 0.4 to −0.75 at Emerald Lake in less than a decade. Morris et al (2013c) demonstrated using a generalized linear mixed model, reductions in the spruce to fir pollen ration is a robust response variable (p < 0.001) to spruce beetle outbreaks, shifting by a factor of 2:1 between pre-outbreak (1950 and 1985) and outbreak periods (1985 to 2005).…”

Spruce Beetle Biology, Ecology and Management in the Rocky Mountains: An Addendum to Spruce Beetle in the Rockies

“…Brunelle et al (2008) [21] demonstrated that the presence of mountain pine beetle, D. ponderosae Hopkins, macrofossil remains in lake sediment cores could be used to date mountain pine beetle outbreaks in the northern Rocky Mountains back to the Holocene. Morris and Brunelle [22] and Morris et al [23] analyzed pollen and other indicators in lake sediment cores to identify potential spruce beetle outbreaks in southern Utah. Applying these methods, Morris et al [20] were able to successfully identify the severe spruce beetle outbreak that occurred on the Wasatch Plateau from mid-1980s through the early 1990s.…”

The role of palaeoecological records in assessing ecosystem services

“…Where insect remains are poorly preserved, such as in alkaline lakes, fossil pollen assemblages and geochemical analysis of bulk material in lake sediment sequences can be used to indicate the timing of past outbreaks of insect defoliators (Morris et al, 2010(Morris et al, , 2013. Morris and Brunelle (2012), for example, showed that ratios of host to non-host taxa pollen accumulation rates can provide a conservative estimate of past, large magnitude outbreaks of spruce bark beetles (Dendroctonus rufipennis Kirby).…”

“…Furthermore, a key strength of lake sediment-based reconstructions of past pest outbreaks is the ability to reconstruct the cascading effects of infestations on ecosystem processes such as soil erosion (and the soil erosion protection service provided by this process) and N leaching (and the service of nutrient pollution control) when combined with additional biogeochemical proxies such as sedimentary geochemistry and stable isotope analysis (see Sections 2.1 and 2.2). These factors in turn determine forest response to disturbance (Morris et al, 2013;McLauchlan et al, 2014); therefore unpicking the feedback mechanisms between them is an important area of current research (see the Novus Research Coordination Network for more information: https://novusrcn.wordpress.com/tag/nitrogen/).…”

“…Output from these exercises vary in complexity from simple land cover maps (e.g. Naidoo et al, 2008) to complex models incorporating interactions between ecosystem components and processes (e.g. Goldstein et al, 2012).…”