1,721,107 research outputs found
Setting aside areas for conservation does not increase disturbances in temperate forests
No full textAbstract Forest disturbances are increasing in many parts of the globe, posing a considerable challenge for forest management. Simultaneously, setting aside forests for conservation is considered an important approach to halt ongoing biodiversity loss. While the potential for increasing disturbances is often invoked as an argument against creating forest reserves within the matrix of managed forest landscapes, quantitative evidence for the impact of conservation areas on forest disturbance regimes remains scarce. Here, we contrasted forest disturbance regimes in actively managed and set‐aside areas throughout Germany. We made use of a network of strict forest reserves protected for at least 35 years (i.e. set‐aside areas) and identified comparable managed forests by controlling for differences in species composition, climate and topography ( n = 314 pairs of managed and set‐aside areas with 20 ha in size). A remote‐sensing‐based forest disturbance map with annual disturbance records for the years 1986 to 2020 was used to quantify disturbance regimes. Within the context of the coupled human and natural disturbance regimes of Central Europe, we here focused on canopy openings initiated by naturally occurring agents like wind‐throw, drought and bark beetle infestations. Our main objective was to identify the impact of setting aside forests on disturbance rate, frequency, patch density, patch size and severity. We found that set‐aside areas had, on average, a 22% lower disturbance rate and a 32% lower disturbance severity compared with actively managed forests, with no significant differences detected for disturbance patch size, patch density and frequency. Lower disturbance activity in set‐aside areas was particularly pronounced in mixed and broadleaved forest types. The dampening effect of strict forest reserves strengthened in pulse disturbance years, that is years with very high disturbance activity caused by extreme storm or drought events. Synthesis and applications : We found no evidence that setting aside forests for biodiversity conservation amplifies disturbances in temperate forests of Central Europe. Conversely, we found that strict forest reserves had lower disturbance activity, particularly in years affected by severe climatic extremes. We conclude that considerations of disturbance should not limit the incorporation of reserves into landscape management in temperate forests.Zusammenfassung Störungen im Wald nehmen in vielen Teilen der Welt zu und stellen eine erhebliche Herausforderung für das Waldmanagement dar. Gleichzeitig gilt das Ausweisen von Waldschutzgebieten als ein wichtiger Ansatz, um den fortschreitenden Verlust der Biodiversität zu stoppen. Während das Potenzial für zunehmende Störungen oft als Argument gegen die Einrichtung von Waldschutzgebieten innerhalb der Matrix von bewirtschafteten Waldlandschaften angeführt wird, gibt es wenig quantitative Evidenz für die Auswirkungen von Schutzgebieten auf die Störungsregimes in Wäldern. In dieser Studie wurden Störungsregimes in aktiv bewirtschafteten Wäldern mit jenen in Waldschutzgebieten über ganz Deutschland verglichen. Wir nutzten dazu ein Netzwerk von Waldschutzgebieten, die seit mindestens 35 Jahren unter Schutz stehen und identifizierten vergleichbare bewirtschaftete Wälder mit ähnlicher Baumartenzusammensetzung, Klima und Topografie ( n = 314 Paare von bewirtschafteten und geschützten Gebieten mit je 20 ha). Für die Quantifizierung der Störungsregime verwendeten wir eine auf Fernerkundung basierende Karte der Waldstörungen mit jährlicher Auflösung für die Jahre 1986 bis 2020. Wir fokussierten uns auf Kronenöffnungen, die durch natürlich vorkommende Agenten wie Windwurf, Dürre und Borkenkäferbefall ausgelöst wurden. Unser Hauptziel war es, die Auswirkungen von Waldschutzgebieten auf die Rate, Häufigkeit, Menge, Größe und Stärke von Störungen zu quantifizieren. Waldschutzgebiete haben im Durchschnitt eine um 22% niedrigere Störungsrate und eine um 32% geringere Störungsstärke im Vergleich zu aktiv bewirtschafteten Wäldern, wobei wir keine signifikanten Unterschiede in der Größe, Menge und Häufigkeit von Störungen feststellen konnten. Die geringere Störungsaktivität in Schutzgebieten war insbesondere in Misch‐ und Laubwaldtypen ausgeprägt. Der dämpfende Effekt von Waldschutzgebieten war in Jahren mit Störungspulsen, d. h. Jahren mit sehr hoher Störungsaktivität aufgrund extremer Sturm‐ oder Dürreereignisse, besonders ausgeprägt. Synthese und Anwendungen: Wir fanden keine Hinweise darauf, dass Wäldern, die zum Schutz der Biodiversität dienen, Störungen in temperierten Wäldern Mitteleuropas verstärken. Waldschutzgebiete wiesen insbesondere in Jahren mit Extremereignissen eine geringere Störungsaktivität auf als aktiv bewirtschaftete Wälder. Wir schließen daraus, dass Schutzgebiete in das Landschaftsmanagement gemäßigter Wälder integriert werden können ohne das Störungsrisiko zu erhöhen.Abstract Forest disturbances are increasing in many parts of the globe, posing a considerable challenge for forest management. Simultaneously, setting aside forests for conservation is considered an important approach to halt ongoing biodiversity loss. While the potential for increasing disturbances is often invoked as an argument against creating forest reserves within the matrix of managed forest landscapes, quantitative evidence for the impact of conservation areas on forest disturbance regimes remains scarce. Here, we contrasted forest disturbance regimes in actively managed and set‐aside areas throughout Germany. We made use of a network of strict forest reserves protected for at least 35 years (i.e. set‐aside areas) and identified comparable managed forests by controlling for differences in species composition, climate and topography ( n = 314 pairs of managed and set‐aside areas with 20 ha in size). A remote‐sensing‐based forest disturbance map with annual disturbance records for the years 1986 to 2020 was used to quantify disturbance regimes. Within the context of the coupled human and natural disturbance regimes of Central Europe, we here focused on canopy openings initiated by naturally occurring agents like wind‐throw, drought and bark beetle infestations. Our main objective was to identify the impact of setting aside forests on disturbance rate, frequency, patch density, patch size and severity. We found that set‐aside areas had, on average, a 22% lower disturbance rate and a 32% lower disturbance severity compared with actively managed forests, with no significant differences detected for disturbance patch size, patch density and frequency. Lower disturbance activity in set‐aside areas was particularly pronounced in mixed and broadleaved forest types. The dampening effect of strict forest reserves strengthened in pulse disturbance years, that is years with very high disturbance activity caused by extreme storm or drought events. Synthesis and applications : We found no evidence that setting aside forests for biodiversity conservation amplifies disturbances in temperate forests of Central Europe. Conversely, we found that strict forest reserves had lower disturbance activity, particularly in years affected by severe climatic extremes. We conclude that considerations of disturbance should not limit the incorporation of reserves into landscape management in temperate forests.Zusammenfassung Störungen im Wald nehmen in vielen Teilen der Welt zu und stellen eine erhebliche Herausforderung für das Waldmanagement dar. Gleichzeitig gilt das Ausweisen von Waldschutzgebieten als ein wichtiger Ansatz, um den fortschreitenden Verlust der Biodiversität zu stoppen. Während das Potenzial für zunehmende Störungen oft als Argument gegen die Einrichtung von Waldschutzgebieten innerhalb der Matrix von bewirtschafteten Waldlandschaften angeführt wird, gibt es wenig quantitative Evidenz für die Auswirkungen von Schutzgebieten auf die Störungsregimes in Wäldern. In dieser Studie wurden Störungsregimes in aktiv bewirtschafteten Wäldern mit jenen in Waldschutzgebieten über ganz Deutschland verglichen. Wir nutzten dazu ein Netzwerk von Waldschutzgebieten, die seit mindestens 35 Jahren unter Schutz stehen und identifizierten vergleichbare bewirtschaftete Wälder mit ähnlicher Baumartenzusammensetzung, Klima und Topografie ( n = 314 Paare von bewirtschafteten und geschützten Gebieten mit je 20 ha). Für die Quantifizierung der Störungsregime verwendeten wir eine auf Fernerkundung basierende Karte der Waldstörungen mit jährlicher Auflösung für die Jahre 1986 bis 2020. Wir fokussierten uns auf Kronenöffnungen, die durch natürlich vorkommende Agenten wie Windwurf, Dürre und Borkenkäferbefall ausgelöst wurden. Unser Hauptziel war es, die Auswirkungen von Waldschutzgebieten auf die Rate, Häufigkeit, Menge, Größe und Stärke von Störungen zu quantifizieren. Waldschutzgebiete haben im Durchschnitt eine um 22% niedrigere Störungsrate und eine um 32% geringere Störungsstärke im Vergleich zu aktiv bewirtschafteten Wäldern, wobei wir keine signifikanten Unterschiede in der Größe, Menge und Häufigkeit von Störungen feststellen konnten. Die geringere Störungsaktivität in Schutzgebieten war insbesondere in Misch‐ und Laubwaldtypen ausgeprägt. Der dämpfende Effekt von Waldschutzgebieten war in Jahren mit Störungspulsen, d. h. Jahren mit sehr hoher Störungsaktivität aufgrund extremer Sturm‐ oder Dürreereignisse, besonders ausgeprägt. Synthese und Anwendungen: Wir fanden keine Hinweise darauf, dass Wäldern, die zum Schutz der Biodiversität dienen, Störungen in temperierten Wäldern Mitteleuropas verstärken. Waldschutzgebiete wiesen insbesondere in Jahren mit Extremereignissen eine geringere Störungsaktivität auf als aktiv bewirtschaftete Wälder. Wir schließen daraus, dass Schutzgebiete in das Landschaftsmanagement gemäßigter Wälder integriert werden können ohne das Störungsrisiko zu erhöhen.H2020 European Research Council https://doi.org/10.13039/100010663Bundesministerium für Ernährung und Landwirtschaft https://doi.org/10.13039/501100005908Bundesministerium für Umwelt, Naturschutz, nukleare Sicherheit und Verbraucherschutz https://doi.org/10.13039/50110001354
Effects of disturbance patterns and deadwood on the microclimate in European beech forests
No full textMore frequent and severe disturbances increasingly open the forest canopy and initiate tree regeneration. Simultaneously, increasing weather extremes, such as drought and heat, are threatening species adapted to cool and moist climate. The magnitude of the microclimatic buffering capacity of forest canopies to mitigate hot and dry weather conditions and its disturbance-induced reduction remains poorly quantified. Also, the influence of disturbance legacies (e.g., deadwood) on forest microclimate is unresolved. In a unique manipulation experiment we investigated (i) the microclimatic buffering capacity of forest canopies in years with different climatic conditions; (ii) the impacts of spatial disturbance patterns on surface light and microclimate; and (iii) the effect of deadwood presence and type on microclimate. Treatments included two disturbance patterns (i.e., aggregated and distributed), four deadwood types (i.e., standing, downed, standing and downed, removed), and one untreated control (i.e., nine treatments in total), replicated at five sites dominated by European beech (Fagus sylvatica L.) in southeastern Germany. We measured forest floor light conditions and derived diurnal extremes and variation in temperature (T) and vapor pressure deficit (VPD) during four consecutive summer seasons (2016 – 2019). The buffering capacity of intact forest canopies was higher in warm and dry years. Surface light was significantly higher in spatially aggregated disturbance gaps compared to distributed disturbances of similar severity. An increase in surface light by 10 % relative to closed canopies elevated T(max) and VPD(max) by 0.42°C and 0.04 kPa, respectively. Deadwood presence and type did not affect the forest microclimate significantly. Microclimatic buffering under forest canopies can dampen the effects of climate change. However, increasing canopy disturbances result in more light penetrating the canopy, reducing the microclimatic buffering capacity of forests. We conclude that forest management should foster microclimatic buffering in forests as one element of a multi-pronged strategy to counter climate change
Assessing the Economic Resilience of Different Management Systems to Severe Forest Disturbance
No full textGiven the drastic changes in the environment, resilience is a key focus of ecosystem management. Yet, the quantification of the different dimensions of resilience remains challenging, particularly for long-lived systems such as forests. Here we present an analytical framework to study the economic resilience of different forest management systems, focusing on the rate of economic recovery after severe disturbance. Our framework quantifies the post-disturbance gain in the present value of a forest relative to a benchmark system as an indicator of economic resilience. Forest values and silvicultural interventions were determined endogenously from an optimization model and account for risks affecting tree survival. We consider the effects of differences in forest structure and tree growth post disturbance on economic resilience. We demonstrate our approach by comparing the economic resilience of continuous cover forestry against a clear fell system for typical conditions in Central Europe. Continuous cover forestry had both higher economic return and higher economic resilience than the clear fell system. The economic recovery from disturbance in the continuous cover system was between 18.2 and 51.5% faster than in the clear fell system, resulting in present value gains of between 1733 and 4535 € ha(−1). The advantage of the continuous cover system increased with discount rate and stand age, and was driven by differences in both stand structure and economic return. We conclude that continuous cover systems can help to address the economic impacts of increasing disturbances in forest management
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Dispelling the Myths Behind First-author Citation Counts
Full text linkWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
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