Ecological restoration for biodiversity conservation triggers response of bark beetle pests and their natural predators

Abstract The restoration of forest structure and function is increasingly being used in boreal forests in order to halt the loss of biodiversity. Often ecological restoration is aimed at increasing the volume of dead and dying trees to enhance the biodiversity of deadwood-dependent organisms, but it may also increase population sizes of pest bark beetle species, even several years following restoration. Herein, we used a large-scale restoration experiment in Northern Sweden to assess the 5 years post-restoration effects of restorative gap cutting and prescribed burning on the populations of a set of economically harmful pest bark beetles (Ips typographus, Polygraphus poligraphus, Tomicus piniperda and Pityogenes chalcographus) and the most important predators of bark beetles, Thanasimus spp. In addition, we assessed the effects of forest stand characteristics at stand and landscape scale on the abundance of I. typographus. Five years post-restoration, gap-cut stands supported the highest abundances of P. poligraphus and contained the highest count of spruce trees newly attacked by bark beetles. By contrast, prescribed burning generally sustained the lowest abundances of pest bark beetles, especially I. typographus and P. poligraphus, and the highest abundance of their natural predators Thanasimus spp. The population abundance of I. typographus was also positively affected by the area of clear cuts within a 500 m radius from the stand. In conclusion, prescribed burning appears to be a safer method for ecological restoration than gap cutting in the long-term. According to our results, a risk of a local bark beetle outbreak still remains 5 years following the initiation of ecological restoration treatments on spruce-dominated mature gap-cut stands.

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Bark Beetle Population Dynamics in the Anthropocene: Challenges and Solutions

10.20944/preprints201810.0640.v1 ◽

2018 ◽

Author(s):

Peter H. W. Biedermann ◽

Jean-Claude Grégoire ◽

Axel Gruppe ◽

Jonas Hagge ◽

Almuth Hammerbacher ◽

...

Keyword(s):

Population Dynamics ◽

Bark Beetle ◽

Collaborative Research ◽

Bark Beetles ◽

Large Scale ◽

Ips Typographus ◽

Ecological Framework ◽

Beetle Population ◽

Spruce Bark ◽

Important Pest

Tree-killing bark beetles are the most economically important insects in conifer forests worldwide. Yet  despite >200 years of research, the drivers of population eruptions or crashes are still not fully understood, precluding reliable predictions of the effects of global change on beetle population dynamics and impacts on ecosystems and humans.  We critically analyze potential biotic and abiotic drivers of population dynamics of the European spruce bark beetle (Ips typographus) and present a novel ecological framework that integrates the multiple drivers governing this bark beetle system. We call for large-scale collaborative research efforts to improve our understanding of the population dynamics of this important pest; an approach that might serve as a blueprint for other eruptive forest insects.

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Common species link global ecosystems to climate change: dynamical evidence in the planktonic fossil record

Proceedings of The Royal Society B Biological Sciences ◽

10.1098/rspb.2017.0722 ◽

2017 ◽

Vol 284 (1858) ◽

pp. 20170722 ◽

Cited By ~ 11

Author(s):

Bjarte Hannisdal ◽

Kristian Agasøster Haaga ◽

Trond Reitan ◽

David Diego ◽

Lee Hsiang Liow

Keyword(s):

Large Scale ◽

Planktonic Foraminifera ◽

Deep Ocean ◽

Common Species ◽

Ecosystem Structure ◽

Environmental Forcing ◽

Widespread Species ◽

Quantitative Evidence ◽

And Function

Common species shape the world around us, and changes in their commonness signify large-scale shifts in ecosystem structure and function. However, our understanding of long-term ecosystem response to environmental forcing in the deep past is centred on species richness, neglecting the disproportional impact of common species. Here, we use common and widespread species of planktonic foraminifera in deep-sea sediments to track changes in observed global occupancy (proportion of sampled sites at which a species is present and observed) through the turbulent climatic history of the last 65 Myr. Our approach is sensitive to relative changes in global abundance of the species set and robust to factors that bias richness estimators. Using three independent methods for detecting causality, we show that the observed global occupancy of planktonic foraminifera has been dynamically coupled to past oceanographic changes captured in deep-ocean temperature reconstructions. The causal inference does not imply a direct mechanism, but is consistent with an indirect, time-delayed causal linkage. Given the strong quantitative evidence that a dynamical coupling exists, we hypothesize that mixotrophy (symbiont hosting) may be an ecological factor linking the global abundance of planktonic foraminifera to long-term climate changes via the relative extent of oligotrophic oceans.

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Emergence levels of pine shoot beetles from roundwood piles of Scots pine and the cascading damage in the surrounding forests

Silva Fennica ◽

10.14214/sf.10525 ◽

2021 ◽

Vol 55 (5) ◽

Author(s):

Markus Melin ◽

Tiina Ylioja ◽

Leena Aarnio ◽

Katri Hamunen ◽

Seppo Nevalainen ◽

...

Keyword(s):

Pinus Sylvestris ◽

Scots Pine ◽

Bark Beetle ◽

Bark Beetles ◽

Coniferous Forests ◽

The Future ◽

Forest Legislation ◽

Pine Shoot Beetles

Bark beetles are amongst the most aggressive pest agents of coniferous forests. Due to this, many boreal countries have designated laws aiming to lower the risk of bark beetle epidemics. Finlandâs forest legislation has pre-emptive measures targeted against bark beetles, and for Scots pine ( L.), the law concerns pine shoot beetles ( spp.). This study used data collected around 25 piles of Scots pine roundwood that were harvested in the winter but left in the forest until the following November. Thus, the pine shoot beetles were able to use the piles for breeding. We assessed the number of emerged insects from the piles and the cascading damage they caused in the surrounding forests. All roundwood piles, regardless of their volume, were used by the beetles for breeding. Highest densities of beetle exit holes were found from the parts of the log with thick and intact bark. If the bark of the log was damaged by the harvester head, the number of beetles decreased significantly. Depending on the volume of the roundwood pile, the cascading damage (fallen shoots) was noticeable up to ca. 40â60 m from the roundwood pile. Storing of piles smaller than 50 m did not cause excess damage. The number of fallen shoots per tree was generally below the known thresholds for when growth losses can occur. However, the study was conducted in mature forests, and it can be assumed that the recorded damage levels would severely affect the growth of young pines, raising the question of where to store the roundwood. As with other bark beetles, the role of beetles as damage agents may change in the future, but based on this as well as past studies, the species can be viewed as a notable damage agents only around long-term wood storage sites in the current northern conditions.Pinus sylvestrisTomicus3Tomicus

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Spruce resins constitute a strong sink for methane (CH4)

10.5194/egusphere-egu2020-2892 ◽

2020 ◽

Author(s):

Katerina Machacova ◽

Thomas Schindler ◽

Ülo Mander ◽

Kaido Soosaar

Keyword(s):

Greenhouse Gas ◽

Norway Spruce ◽

Bark Beetle ◽

Boreal Forests ◽

Large Scale ◽

Temperate Zone ◽

Exchange Potential ◽

Potential Control ◽

Clear Cutting ◽

Roof Experiment

Woody plants are known to emit methane (CH4) as an important greenhouse gas into the atmosphere. Recent studies show that tree stems might be also sinks for CH4; however, the mechanisms of CH4 uptake and its fate are unknown. Norway spruce (Picea abies) is characterised as negligible CH4 source in boreal forests. Even though spruce trees have been widely planted for its wood in large-scale monocultures in European temperate forests, no studies have focused on their CH4 exchange potential in the temperate zone.We determined stems of Norway spruce growing in a temperate zone aiming to find out whether the tree stems exchange CH4 with the atmosphere and how they contribute to the forest trace gas exchange.The measurements were performed at the experimental station of the &#8216;Kranzberg Forest Roof Experiment&#8217; near Freising, Germany, in June 2019. Fluxes of CH4 in mature tree stems were measured using non-steady-state stem chamber systems (n=32) installed in stem vertical profile approx. two weeks prior to measurements using a portable greenhouse gas analyser. Moreover, resins sampled from spruce stems were investigated for their CH4 exchange potential. Control measurements were performed to ensure that the fluxes do not originate from used chamber materials, in particular silicones used for chamber installation.Our preliminary results show that the spruce stems can be a strong sink for CH4 (-0.288 &#177; 0.053 mg CH4 m-2 stem area h-1, mean &#177; s.e.), even if a small amount of resin is present on the bark. The stems exuded resins to different extent (covering 4.8 &#177; 1.3% of the stem surface area in chambers), partly as a result of smoothening of rough surface layers of dead bark for chamber installation. However, even spruce stems without obvious &#8220;injuries&#8221; released small amounts of resins for unknown reasons (response to drought, bark-beetle attack, etc.?). The incubated resin samples consistently consumed CH4 (-12.0 &#177; 1.7 mg CH4 m-2 resin area h-1). Moreover, the detected stem CH4 uptake negatively correlated with the resin occurrence in the stem chambers (R&#178; = 0.884). After re-calculation of the stem fluxes to resin area, the CH4 consumption rates of stems and resin samples were in the same order of magnitude at median level (-13.2 and -12.0 mg CH4 m-2 resin area h-1, resp.).Concluded, the spruce resins appear to be a very strong and until now undiscovered sink for CH4. Even one small droplet of resins on bark can turn the known negligible CH4 exchange of intact spruce stems into strong CH4 sinks, having thus severe impact on the overall forest CH4 balance. This consumption potential of fresh resins should be considered by estimation of forest ecosystem CH4 balance especially in areas, where resin bleeding is widely spread or is to be expected (bark-beetle areas, drought events, tree harvest, clear-cutting).&#160;AcknowledgementThis research was supported by the Czech Science Foundation (17-18112Y) and National Sustainability Program I (LO1415). We thank Prof. Thorsten Grams for all his kind support, and Jan Hrdli&#269;ka and Thomas Feuerbach for their technical support.&#160;&#160;

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Bark beetle outbreak enhances biodiversity and foraging habitat of native bees in alpine landscapes of the southern Rocky Mountains

Scientific Reports ◽

10.1038/s41598-020-73273-z ◽

2020 ◽

Vol 10 (1) ◽

Author(s):

Thomas Seth Davis ◽

Paul R. Rhoades ◽

Andrew J. Mann ◽

Terry Griswold

Keyword(s):

Bark Beetle ◽

Forest Structure ◽

Bark Beetles ◽

Large Scale ◽

Tree Mortality ◽

Growing Season ◽

Floral Resources ◽

Foraging Habitat ◽

Pollinator Community ◽

Large Scale Disturbance

Abstract Landscape-scale bark beetle outbreaks alter forest structure with direct and indirect effects on plants and animals in forest ecosystems. Using alpine spruce forest and a native bee community as a study system, we tested how tree mortality from bark beetles impacts bee foraging habitats and populations. Bees were collected across the growing season (early-, middle-, and late-season) for two years using passive trapping methods, and collections were used to analyze patterns in species abundances and diversity. Three important findings emerged: (1) forest stands that were post-outbreak had 62% higher floral density and 68% more floral species during peak bloom, respectively, than non-affected stands; (2) bee captures were highest early-season (June) and were not strongly affected by bark beetle outbreak; however, mean number of bee species and Shannon–Weiner diversity were significantly higher in post-outbreak stands and this effect was pronounced early in the growing season. Corresponding analysis of β-diversity indicated higher accumulation of bee biodiversity in post-outbreak stands and a turnover in the ratio of Bombus: Osmia; (3) bee captures were linked to variation in foraging habitat, but number of bee species and diversity were more strongly predicted by forest structure. Our results provide evidence of increased alpine bee biodiversity in post-outbreak stands and increased availability of floral resources. We conclude that large-scale disturbance from bark beetle outbreaks may drive shifts in pollinator community composition through cascading effects on floral resources, mediated via mortality of overstory trees.

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Efficacy of synthetic lures for pine bark beetle monitoring

Journal of Forest Science ◽

10.17221/139/2021-jfs ◽

2022 ◽

Vol 68 (No. 1) ◽

pp. 19-25

Author(s):

Miloš Knížek ◽

Jan Liška ◽

Adam Véle

Keyword(s):

Bark Beetle ◽

Bark Beetles ◽

Large Scale ◽

Ips Typographus ◽

Pine Plantations ◽

The Czech Republic ◽

Long Run ◽

Baited Traps ◽

Pine Trees ◽

Ips Sexdentatus

The Scots pine (Pinus sylvestris) plantations in central Europe are currently damaged by a large-scale infestation by bark beetles (Scolytinae). Ips acuminatus and Ips sexdentatus are among the most aggressive species causing infestations of pine trees that are currently simultaneously attacked by Ips typographus. In pine plantations prone to damage, it is therefore necessary to carry out the bark beetle monitoring. One of the used methods is the pheromone bark beetle trapping using synthetic lures. The efficacy of synthetic lures differs. We tested the efficacy of commercially available lures used in the protection of pine trees. In total, we deployed 10 trap series, each consisting of traps with eight different lures and two unbaited traps (controls). Ips acuminatus and I. sexdentatus were most abundantly captured in Pheagr-IAC- and Sexowit-baited traps. Interestingly, the spruce species I. typographus was also captured and most often found in traps with Pheagr-IAC and Erosowit Tube lures. The number of captured beetles was consistent with the gradation phase of bark beetles. Our results suggest the suitability of pheromone traps for bark beetle monitoring. The use of Sexowit can be recommended especially in southwestern Moravia, where I. sexdentatus occurs in high numbers in the long run. In other parts of the Czech Republic, Pheagr-IAC alone can be used with sufficient efficacy. The use of the Erosowit Tube lure is also suitable for I. typographus and I. sexdentatus monitoring.

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Effects of national ecological restoration projects on carbon sequestration in China from 2001 to 2010

Proceedings of the National Academy of Sciences ◽

10.1073/pnas.1700294115 ◽

2018 ◽

Vol 115 (16) ◽

pp. 4039-4044 ◽

Cited By ~ 92

Author(s):

Fei Lu ◽

Huifeng Hu ◽

Wenjuan Sun ◽

Jiaojun Zhu ◽

Guobin Liu ◽

...

Keyword(s):

Ecological Restoration ◽

Large Scale ◽

Field Investigation ◽

Soil C ◽

Grassland Ecosystems ◽

C Stocks ◽

Scale Field ◽

Large Scale Field ◽

Degraded Ecosystems

The long-term stressful utilization of forests and grasslands has led to ecosystem degradation and C loss. Since the late 1970s China has launched six key national ecological restoration projects to protect its environment and restore degraded ecosystems. Here, we conducted a large-scale field investigation and a literature survey of biomass and soil C in China’s forest, shrubland, and grassland ecosystems across the regions where the six projects were implemented (∼16% of the country’s land area). We investigated the changes in the C stocks of these ecosystems to evaluate the contributions of the projects to the country’s C sink between 2001 and 2010. Over this decade, we estimated that the total annual C sink in the project region was 132 Tg C per y (1 Tg = 1012 g), over half of which (74 Tg C per y, 56%) was attributed to the implementation of the projects. Our results demonstrate that these restoration projects have substantially contributed to CO2 mitigation in China.

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Seagrass seed bank spatial structure and function following a large-scale decline

Marine Ecology Progress Series ◽

10.3354/meps13668 ◽

2021 ◽

Vol 665 ◽

pp. 75-87

Author(s):

JC Jarvis ◽

SA McKenna ◽

MA Rahseed

Keyword(s):

Spatial Structure ◽

Water Depth ◽

Seed Bank ◽

Large Scale ◽

Halophila Ovalis ◽

World Heritage Area ◽

Species Specific ◽

And Function ◽

Heritage Area

We examined the spatial structure (distribution, density) and function (viability) of the seagrass sediment seed bank, the storage of viable propagules (e.g. seeds, tubers, diaspores) in the sediment over time,in the northern Great Barrier Reef World Heritage Area in Cairns, Queensland, following a large-scale decline in seagrass area. A spatially explicit seagrass seed bank analysis was paired with a long-term annual assessment of seagrass distribution to assess seed bank spatial patterns and their relationship with the recovery and presence of seagrass, and water depth. Four years post-decline, the seed bank contained Zostera muelleri, Halodule uninervis, Halophila ovalis and Cymodocea serrulata seeds. Seed banks reflected adjacent meadow community composition; however, the density of seeds for all recorded species was significantly lower than analogous seagrass populations, indicating a reduction in the capacity for recovery from the seed bank. A spatial structure existed in both the total (viable + non-viable) and viable seed bank, and distance between seed clusters ranged from 50-550 m depending on species and seed type. Observed patterns in clustering may be explained by variation in water depth and the past distribution of seagrass in these meadows. These results demonstrate that the distribution of seagrass seeds within the seed bank, which directly influences the natural recovery of seagrass communities, is not uniform across species and may result in patchy recovery of the meadows. Therefore, the resilience provided by the seed bank in seagrass communities should not be viewed as a static level of insurance for the entire meadow, but rather as dynamic and species-specific, with variability over both space and time.

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Private Forest Owner Characteristics Affect European Spruce Bark Beetle Management under an Extreme Weather Event and Host Tree Density

Forests ◽

10.3390/f12030346 ◽

2021 ◽

Vol 12 (3) ◽

pp. 346

Author(s):

Maarten de Groot ◽

Jurij Diaci ◽

Kaja Kandare ◽

Nike Krajnc ◽

Rok Pisek ◽

...

Keyword(s):

Bark Beetle ◽

Bark Beetles ◽

Large Scale ◽

Forest Owner ◽

Private Forest ◽

Ice Storm ◽

Forest Owners ◽

Forest Ownership ◽

Private Owner ◽

Owner Characteristics

In the last few decades, an increasing number and intensity of bark beetle outbreaks have plagued the forests of Europe and North America. Bark beetle management is directly related to forest owner characteristics, although this relationship is not well understood. The purpose of the study was to investigate the influence of forest owner characteristics on the amount and timing of sanitary felling under different disturbance regimes and quantities of Norway spruce. We combined different databases on sanitary felling, the timing of sanitary felling, and forest owner characteristics for Slovenia from 2014 to 2018 and analyzed the amount and timing of sanitary felling in relation to forest owner characteristics. We found that the timing in winter and the amount of sanitary felling were positively associated with the distance of the owner’s residence to the forest parcel. Larger parcels were more affected by bark beetles but did not have later timing of cutting in the summer period as was hypothesized. The timing of sanitary felling decreased with property size, while with the probability of sanitary felling, the effect of property depended on the ice storm and the amount of spruce. The size of the settlement, the permanent address of the private owner, and timing of sanitary felling were positively associated but also depended on the amount of spruce. Gender and age did not have an important influence on the amount and timing of sanitary felling. Forest owners are an important factor in effective bark beetle management. This study highlights the private forest ownership characteristics that should be emphasized in order to fight bark beetle outbreaks in the event of large-scale disturbances. Governments should support forest owners who are at greater risk of bark beetle outbreaks and less efficient in managing outbreaks. Furthermore, landowner characteristics should be included when forecasting bark beetle outbreaks.

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Landscape-Scale Drivers of Resistance and Resilience to Bark Beetles: A Conceptual Susceptibility Model

Forests ◽

10.3390/f12060798 ◽

2021 ◽

Vol 12 (6) ◽

pp. 798

Author(s):

Marcella A. Windmuller-Campione ◽

Justin DeRose ◽

James N. Long

Keyword(s):

Conceptual Model ◽

Bark Beetle ◽

Bark Beetles ◽

Large Scale ◽

Tree Mortality ◽

Multiple Scales ◽

Ecological Factors ◽

Management Approach ◽

Direct Role ◽

Interior West

Bark beetle (Dendroctonus spp.) outbreaks in the middle latitudes of western North America cause large amounts of tree mortality, outstripping wildfire by an order of magnitude. While temperatures play an important, and direct role in the population dynamics of ectothermic bark beetles, an equally important influence is the nature of the host substrate—the structure and composition of forested communities. For many of the dominant tree species in the western United States, “hazard” indices have been developed for specific bark beetles, which generally include three key variables—host tree size, absolute or relative density of the stand, and percentage of host composition. We provide a conceptual model to apply these three variables across forest ecosystems and bark beetles that shifts the thinking from a species–specific model to a model which focuses on the underlying ecological factors related to bark beetle outbreak susceptibility. We explored the use of our model across multiple scales using the Forest Inventory and Analysis database: Interior West, USA; the states of Colorado and Arizona; and specific national forests within Arizona that are implementing a large-scale restoration effort. We demonstrated that across the Interior West and Colorado, the vast majority of forests have moderate to high susceptibility to bark beetles. Our conceptual model maintains the simplicity of previous “hazard” models but acknowledges the need to consider scale when managing bark beetles. It also shifts the management approach from resistance thinking to the development of “associational resilience”, where the focus is not on any one individual stand or area but the longer-term perspective of forest persistence across the landscape.

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