The value of linking paleoecological and neoecological perspectives to understand spatially-explicit ecosystem resilience     

Buma  B.  Harvey  B. J.  Gavin  D. G.  Kelly  R.  Loboda  T.  McNeil  B. E.  Marlon  J. R.  Meddens  A. J. H.  Morris  J. L.  Raffa  K. F.  Shuman  B.  Smithwick  E. A. H.  McLauchlan  K. K. 《Landscape Ecology》2019,34(1):17-33

Context

Predicting ecosystem resilience is a challenge, especially as climate change alters disturbance regimes and conditions for recovery. Recent research has highlighted the importance of spatially-explicit disturbance and resilience processes to long-term ecosystem dynamics. “Neoecological” approaches characterize resilience mechanisms at relatively fine spatio-temporal resolutions, but results are difficult to extrapolate across broad temporal scales or climatic ranges. Paleoecological methodologies can consider the effects of climates that differ from today. However, they are often limited to coarse-grained spatio-temporal resolutions.

Methods

In this synthesis, we describe implicit and explicit examples of studies that incorporate both neo- and paleoecological approaches. We propose ways to build on the strengths of both approaches in an explicit and proactive fashion.

Results

Linking the two approaches is a powerful way to surpass their respective limitations. Aligning spatial scales is critical: Paleoecological sampling design should incorporate knowledge of the spatial characteristics of the disturbance process, and neoecological studies benefit from a longer-term context to their conclusions. In some cases, modeling can incorporate non-spatial data from paleoecological records or emerging spatial paleo-data networks with mechanistic disturbance/recovery processes that operate at fine spatiotemporal scales.

Conclusions

Linking these two complementary approaches is a powerful way to build a complete understanding of ecosystem disturbance and resilience.

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Insecticide resistance: challenge to pest management and basic research     

Brattsten LB  Holyoke CW  Leeper JR  Raffa KF 《Science (New York, N.Y.)》1986,231(4743):1255-1260

The agricultural use of synthetic insecticides usually protects crops but imposes strong selection pressures that can result in the development of resistance. The most important resistance mechanisms are enhancement of the capacity to metabolically detoxify insecticides and alterations in target sites that prevent insecticides from binding to them. Insect control methods must incorporate strategies to minimize resistance development and preserve the utility of the insecticides. The most promising approach, integrated pest management, includes the use of chemical insecticides in combination with improved cultural and biologically based techniques.  相似文献   

Predisposition to bark beetle attack by root herbivores and associated pathogens: Roles in forest decline,gap formation,and persistence of endemic bark beetle populations     

Brian H. Aukema  Jun Zhu  Jesper Møller  Jakob G. Rasmussen  Kenneth F. Raffa 《Forest Ecology and Management》2010

Bark beetles are largely known for their ability to undergo intermittent population eruptions that transform entire landscapes and pose significant economic hardships. However, most species do not undergo outbreaks, and eruptive species usually exert only minor disturbances. Understanding the dynamics of tree-killing noneruptive species can provide insights into how beetles persist at low densities, and how some spatiotemporal patterns of host predisposition may more likely favor breaching eruptive thresholds than others. Elucidating mechanisms behind low-density populations is challenging, however, due to the requirement of long-term monitoring and high degrees of spatial and temporal covariance. We censused more than 2700 trees annually over 7 years, and at the end of 17 years, in a mature red pine plantation. Trees were measured for the presence of bark beetles and wood borers that breed within the primary stem, root weevils that breed in root collars, and bark beetles that breed in basal stems. We quantify the sequence of events that drive this decline syndrome, with the primary emergent pattern being an interaction between below- and above-ground herbivores and their fungal symbionts. This interaction results in an expanding forest gap, with subsequent colonization by early-successional vegetation. Spatial position strongly affects the likelihood of tree mortality. A red pine is initially very likely to avoid attack by tree-killing Ips beetles, but attack becomes increasingly likely as the belowground complex spreads to neighboring trees and eventually make trees susceptible. This system is largely internally driven, as there are strong gap edge, but not stand-edge, effects. Additional stressors, such as drought, can provide an intermittent source of susceptible trees to Ips beetles, and elevated temperature slightly accentuates this effect. New gaps can arise from such trees as they subsequently become epicenters for the full complex of organisms associated with this decline, but this is not common. As Ips populations rise, there is some element of positive feedback, in that the proportion of killed trees that were not first colonized by root organisms increases. This positive feedback is very weak, however, and we propose the slope between beetle population density and reliance on host stress as a quantitative distinction along a gradient from noneruptive through eruptive species. Almost all trees colonized by Ips were subsequently colonized by wood borers, likely a source of negative feedback. We discuss implications to our overall understanding of cross-scale interactions, between-guild interactions, forest declines, and eruptive thresholds.  相似文献   

Effectiveness of modified White's solution at removing ascomycetes associated with the bark beetle Ips pini     

B. J. Kopper  K. D. Klepzig  K. F. Raffa 《Forest Pathology》2003,33(4):237-240

Modified White's solution (1 g HgCl₂/l H₂O) is widely used to surface disinfest bark beetles of their phoretic fungi. We investigated the effectiveness of this solution at disinfesting adult Ips pini from its associated ophiostomatoid fungi. A treatment for 1, 4 or 8 min does not completely rid beetles of phoretic fungi, but does substantially reduce the amount of fungi they carry externally. Sterilizing with modified White's solution caused limited mortality (<16%).  相似文献   

Response: insect resistance     

Brattsten LB  Holyoke CW  Leeper JR  Raffa KF 《Science (New York, N.Y.)》1986,234(4778):803

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