Wenn Marder und Mensch sich begegnen ... : der Marder im Siedlungsraum

Als ursprünglicher Felsbewohner fühlt sich der anpassungsfähige Steinmarder in Dörfern und Städten wohl. Dort fi ndet er ausreichend Nahrung und vielfältige Unterschlupfmöglichkeiten. So erstaunt es nicht, dass Marder ins Siedlungsgebiet ausweichen, wenn sie auf dem Land kein Revier festigen können. Da der Steinmarder ein nachtaktiver Einzelgänger ist, kreuzt er unseren Weg nur selten. Der hervorragende Kletterer hält sich aber gerne in unseren Dachgeschossen auf, sei es zur Aufzucht von Jungen oder um sich tagsüber zu verstecken. Diese Publikation zeigt die Problematik von Mardern in Siedlungsräumen auf, gibt Lösungsvorschläge und Verhaltensmaßnahmen

Estimating the age-diameter relationship of oak species in Switzerland using nonlinear mixed-effects models

Tree growth plays a key role in forest dynamics, yet little attention has been paid to quantifying tree age-diameter relationships. Predicting diameter growth of oaks is especially important due to their role in nature conservation and adaptive forest management under climate change. Thus, we (1) identified environmental variables that shape age-diameter relationships of oaks and (2) quantified the accuracy of predictions based on these variables. We determined the age-diameter relationship of 243 oaks (Quercus spp.) growing in Switzerland by using tree-ring samples. Nonlinear mixed-effects models based on a modified Chapman-Richards equation were fitted with environmental variables included as covariates. The fixed effects elevation, slope and water-holding capacity were most important in shaping the age-diameter relationships. Lower elevations, steeper slopes, north-facing aspects, higher water-holding capacities and moister summers resulted in larger maximum diameters. For 75% of the oaks, age-diameter relationships predicted by the fixed effects matched fairly well the observations (root mean square error between predictions and observations <6cm); the inclusion of random effects reduced root mean square errors for 86% of the trees. These results suggest that water runoff plays a key role for the age-diameter relationships, accompanied by limiting temperature effects at higher elevations. The fixed effects covered variability in site quality, whereas the random effects included tree-specific deviations from expected age-diameter relationships, potentially due to neighbourhood effects such as stand density and competitio

Plot size matters: Toward comparable species richness estimates across plot-based inventories

To understand the state and trends in biodiversity beyond the scope of monitoring programs, biodiversity indicators must be comparable across inventories. Species richness (SR) is one of the most widely used biodiversity indicators. However, as SR increases with the size of the area sampled, inventories using different plot sizes are hardly comparable. This study aims at producing a methodological framework that enables SR comparisons across plot-based inventories with differing plot sizes. We used National Forest Inventory (NFI) data from Norway, Slovakia, Spain, and Switzerland to build sample-based rarefaction curves by randomly incrementally aggregating plots, representing the relationship between SR and sampled area. As aggregated plots can be far apart and subject to different environmental conditions, we estimated the amount of environmental heterogeneity (EH) introduced in the aggregation process. By correcting for this EH, we produced adjusted rarefaction curves mimicking the sampling of environmentally homogeneous forest stands, thus reducing the effect of plot size and enabling reliable SR comparisons between inventories. Models were built using the Conway–Maxell–Poisson distribution to account for the underdispersed SR data. Our method successfully corrected for the EH introduced during the aggregation process in all countries, with better performances in Norway and Switzerland. We further found that SR comparisons across countries based on the country-specific NFI plot sizes are misleading, and that our approach offers an opportunity to harmonize pan-European SR monitoring. Our method provides reliable and comparable SR estimates for inventories that use different plot sizes. Our approach can be applied to any plot-based inventory and count data other than SR, thus allowing a more comprehensive assessment of biodiversity across various scales and ecosystems.publishedVersio

Assessing the response of forest productivity to climate extremes in Switzerland using model-data fusion

The response of forest productivity to climate extremes strongly depends on ambient environmental and site conditions. To better understand these relationships at a regional scale, we used nearly 800 observation years from 271 permanent long-term forest monitoring plots across Switzerland, obtained between 1980 and 2017. We assimilated these data into the 3-PG forest ecosystem model using Bayesian inference, reducing the bias of model predictions from 14% to 5% for forest stem carbon stocks and from 45% to 9% for stem carbon stock changes. We then estimated the productivity of forests dominated by Picea abies and Fagus sylvatica for the period of 1960-2018, and tested for productivity shifts in response to climate along elevational gradient and in extreme years. Simulated net primary productivity (NPP) decreased with elevation (2.86 +/- 0.006 Mg C ha(-1) year(-1) km(-1) for P. abies and 0.93 +/- 0.010 Mg C ha(-1) year(-1) km(-1) for F. sylvatica). During warm-dry extremes, simulated NPP for both species increased at higher and decreased at lower elevations, with reductions in NPP of more than 25% for up to 21% of the potential species distribution range in Switzerland. Reduced plant water availability had a stronger effect on NPP than temperature during warm-dry extremes. Importantly, cold-dry extremes had negative impacts on regional forest NPP comparable to warm-dry extremes. Overall, our calibrated model suggests that the response of forest productivity to climate extremes is more complex than simple shift toward higher elevation. Such robust estimates of NPP are key for increasing our understanding of forests ecosystems carbon dynamics under climate extremes.Peer reviewe

One Century of Forest Monitoring Data in Switzerland Reveals Species- and Site-Specific Trends of Climate-Induced Tree Mortality

Climate-induced tree mortality became a global phenomenon during the last century and it is expected to increase in many regions in the future along with a further increase in the frequency of drought and heat events. However, tree mortality at the ecosystem level remains challenging to quantify since long-term, tree-individual, reliable observations are scarce. Here, we present a unique data set of monitoring records from 276 permanent plots located in 95 forest stands across Switzerland, which include five major European tree species (Norway spruce, Scots pine, silver fir, European beech, and sessile and common oak) and cover a time span of over one century (1898–2013), with inventory periods of 5–10 years. The long-term average annual mortality rate of the investigated forest stands was 1.5%. In general, species-specific annual mortality rates did not consistently increase over the last decades, except for Scots pine forests at lower altitudes, which exhibited a clear increase of mortality since the 1960s. Temporal trends of tree mortality varied also depending on diameter at breast height (DBH), with large trees generally experiencing an increase in mortality, while mortality of small trees tended to decrease. Normalized mortality rates were remarkably similar between species and a modest, but a consistent and steady increasing trend was apparent throughout the study period. Mixed effects models revealed that gradually changing stand parameters (stand basal area and stand age) had the strongest impact on mortality rates, modulated by climate, which had increasing importance during the last decades. Hereby, recent climatic changes had highly variable effects on tree mortality rates, depending on the species in combination with abiotic and biotic stand and site conditions. This suggests that forest species composition and species ranges may change under future climate conditions. Our data set highlights the complexity of forest dynamical processes such as long-term, gradual changes of forest structure, demography and species composition, which together with climate determine mortality rates

One Century of Forest Monitoring Data in Switzerland Reveals Species- and Site-Specific Trends of Climate-Induced Tree Mortality

Climate-induced tree mortality became a global phenomenon during the last century and it is expected to increase in many regions in the future along with a further increase in the frequency of drought and heat events. However, tree mortality at the ecosystem level remains challenging to quantify since long-term, tree-individual, reliable observations are scarce. Here, we present a unique data set of monitoring records from 276 permanent plots located in 95 forest stands across Switzerland, which include five major European tree species (Norway spruce, Scots pine, silver fir, European beech, and sessile and common oak) and cover a time span of over one century (1898–2013), with inventory periods of 5–10 years. The long-term average annual mortality rate of the investigated forest stands was 1.5%. In general, species-specific annual mortality rates did not consistently increase over the last decades, except for Scots pine forests at lower altitudes, which exhibited a clear increase of mortality since the 1960s. Temporal trends of tree mortality varied also depending on diameter at breast height (DBH), with large trees generally experiencing an increase in mortality, while mortality of small trees tended to decrease. Normalized mortality rates were remarkably similar between species and a modest, but a consistent and steady increasing trend was apparent throughout the study period. Mixed effects models revealed that gradually changing stand parameters (stand basal area and stand age) had the strongest impact on mortality rates, modulated by climate, which had increasing importance during the last decades. Hereby, recent climatic changes had highly variable effects on tree mortality rates, depending on the species in combination with abiotic and biotic stand and site conditions. This suggests that forest species composition and species ranges may change under future climate conditions. Our data set highlights the complexity of forest dynamical processes such as long-term, gradual changes of forest structure, demography and species composition, which together with climate determine mortality rates

Low growth resilience to drought is related to future mortality risk in trees

Severe droughts have the potential to reduce forest productivity and trigger tree mortality. Most trees face several drought events during their life and therefore resilience to dry conditions may be crucial to long-term survival. We assessed how growth resilience to severe droughts, including its components resistance and recovery, is related to the ability to survive future droughts by using a tree-ring database of surviving and now-dead trees from 118 sites (22 species, >3,500 trees). We found that, across the variety of regions and species sampled, trees that died during water shortages were less resilient to previous non-lethal droughts, relative to coexisting surviving trees of the same species. In angiosperms, drought-related mortality risk is associated with lower resistance (low capacity to reduce impact of the initial drought), while it is related to reduced recovery (low capacity to attain pre-drought growth rates) in gymnosperms. The different resilience strategies in these two taxonomic groups open new avenues to improve our understanding and prediction of drought-induced mortality.Fil: DeSoto, Lucía. Consejo Superior de Investigaciones Científicas; España. Universidad de Coimbra; PortugalFil: Cailleret, Maxime. Eidgenössische Technische Hochschule Züric; Suiza. Université Aix-marseille; Francia. Swiss Federal Institute for Forest, Snow and Landscape Research; SuizaFil: Sterck, Frank. University of Agriculture Wageningen; Países BajosFil: Jansen, Steven. Universitat Ulm; AlemaniaFil: Kramer, Koen. University of Agriculture Wageningen; Países Bajos. Land Life Company; Países BajosFil: Robert, Elisabeth M. R.. Creaf; España. Vrije Unviversiteit Brussel; Bélgica. Royal Museum for Central Africa; BélgicaFil: Aakala, Tuomas. University of Helsinki; FinlandiaFil: Amoroso, Mariano Martin. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Norte. Instituto de Investigaciones en Recursos Naturales, Agroecología y Desarrollo Rural. - Universidad Nacional de Rio Negro. Instituto de Investigaciones en Recursos Naturales, Agroecología y Desarrollo Rural; ArgentinaFil: Bigler, Christof. Eidgenössische Technische Hochschule Züric; SuizaFil: Camarero, J. Julio. Consejo Superior de Investigaciones Científicas; EspañaFil: Čufar, Katarina. University 0f Ljubljana; EsloveniaFil: Gea Izquierdo, Guillermo. Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria; EspañaFil: Gillner, Sten. Technische Universität Dresden; AlemaniaFil: Haavik, Laurel J.. Servicio Forestal de los Estados Unidos; Estados UnidosFil: Hereş, Ana Maria. Basque Centre For Climate Change; España. Transilvania University of Brasov; RumaniaFil: Kane, Jeffrey M.. Humboldt State University; Estados UnidosFil: Kharuk, Vyacheslav I.. Siberian Federal University; Rusia. Siberian Division of the Russian Academy of Sciences; RusiaFil: Kitzberger, Thomas. Universidad Nacional del Comahue. Centro Regional Universitario Bariloche; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Norte. Instituto de Investigaciones en Biodiversidad y Medioambiente. Universidad Nacional del Comahue. Centro Regional Universidad Bariloche. Instituto de Investigaciones en Biodiversidad y Medioambiente; ArgentinaFil: Klein, Tamir. Weizmann Institute of Science; IsraelFil: Levanič, Tom. Slovenian Forestry Institute; EsloveniaFil: Linares, Juan C.. Universidad Pablo de Olavide; EspañaFil: Mäkinen, Harri. Natural Resources Institute Finland; FinlandiaFil: Oberhuber, Walter. Universidad de Innsbruck; AustriaFil: Papadopoulos, Andreas. Geoponiko Panepistimion Athinon; GreciaFil: Rohner, Brigitte. Eidgenössische Technische Hochschule Zürich; Suiza. Swiss Federal Institute for Forest, Snow and Landscape Research; SuizaFil: Sangüesa Barreda, Gabriel. Universidad de Valladolid; EspañaFil: Stojanovic, Dejan B.. University of Novi Sad; SerbiaFil: Suarez, Maria Laura. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Norte. Instituto de Investigaciones en Biodiversidad y Medioambiente. Universidad Nacional del Comahue. Centro Regional Universidad Bariloche. Instituto de Investigaciones en Biodiversidad y Medioambiente; Argentina. Instituto Nacional de Tecnología Agropecuaria. Centro Regional Patagonia Norte. Estación Experimental Agropecuaria San Carlos de Bariloche; ArgentinaFil: Villalba, Ricardo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza. Instituto Argentino de Nivología, Glaciología y Ciencias Ambientales. Provincia de Mendoza. Instituto Argentino de Nivología, Glaciología y Ciencias Ambientales. Universidad Nacional de Cuyo. Instituto Argentino de Nivología, Glaciología y Ciencias Ambientales; ArgentinaFil: Martínez Vilalta, Jordi. Universitat Autònoma de Barcelona; España. Creaf; Españ

Early-Warning Signals of Individual Tree Mortality Based on Annual Radial Growth

Tree mortality is a key driver of forest dynamics and its occurrence is projected to increase in the future due to climate change. Despite recent advances in our understanding of the physiological mechanisms leading to death, we still lack robust indicators of mortality risk that could be applied at the individual tree scale. Here, we build on a previous contribution exploring the differences in growth level between trees that died and survived a given mortality event to assess whether changes in temporal autocorrelation, variance, and synchrony in time-series of annual radial growth data can be used as early warning signals of mortality risk. Taking advantage of a unique global ring-width database of 3065 dead trees and 4389 living trees growing together at 198 sites (belonging to 36 gymnosperm and angiosperm species), we analyzed temporal changes in autocorrelation, variance, and synchrony before tree death (diachronic analysis), and also compared these metrics between trees that died and trees that survived a given mortality event (synchronic analysis). Changes in autocorrelation were a poor indicator of mortality risk. However, we found a gradual increase in inter- annual growth variability and a decrease in growth synchrony in the last similar to 20 years before mortality of gymnosperms, irrespective of the cause of mortality. These changes could be associated with drought-induced alterations in carbon economy and allocation patterns. In angiosperms, we did not find any consistent changes in any metric. Such lack of any signal might be explained by the relatively high capacity of angiosperms to recover after a stress-induced growth decline. Our analysis provides a robust method for estimating early-warning signals of tree mortality based on annual growth data. In addition to the frequently reported decrease in growth rates, an increase in inter-annual growth variability and a decrease in growth synchrony may be powerful predictors of gymnosperm mortality risk, but not necessarily so for angiosperms.Peer reviewe