Over the last decades, the natural disturbance is increasingly putting pressure on European forests. Shifts in disturbance regimes may compromise forest functioning and the continuous provisioning of ...ecosystem services to society, including their climate change mitigation potential. Although forests are central to many European policies, we lack the long‐term empirical data needed for thoroughly understanding disturbance dynamics, modeling them, and developing adaptive management strategies. Here, we present a unique database of >170,000 records of ground‐based natural disturbance observations in European forests from 1950 to 2019. Reported data confirm a significant increase in forest disturbance in 34 European countries, causing on an average of 43.8 million m3 of disturbed timber volume per year over the 70‐year study period. This value is likely a conservative estimate due to under‐reporting, especially of small‐scale disturbances. We used machine learning techniques for assessing the magnitude of unreported disturbances, which are estimated to be between 8.6 and 18.3 million m3/year. In the last 20 years, disturbances on average accounted for 16% of the mean annual harvest in Europe. Wind was the most important disturbance agent over the study period (46% of total damage), followed by fire (24%) and bark beetles (17%). Bark beetle disturbance doubled its share of the total damage in the last 20 years. Forest disturbances can profoundly impact ecosystem services (e.g., climate change mitigation), affect regional forest resource provisioning and consequently disrupt long‐term management planning objectives and timber markets. We conclude that adaptation to changing disturbance regimes must be placed at the core of the European forest management and policy debate. Furthermore, a coherent and homogeneous monitoring system of natural disturbances is urgently needed in Europe, to better observe and respond to the ongoing changes in forest disturbance regimes.
Shifts in forest disturbance regimes may compromise the continuous provisioning of ecosystem services to society. Although forests in Europe are central to many policies, empirical data for understanding disturbance dynamics are lacking. We present a unique database of >170,000 ground‐based natural disturbance records in European forests from 1950 to 2019. Disturbances significantly increase over the study period, damaging on average 43.8 million m3 of timber volume per year. This is likely a conservative estimate due to under‐reporting. We estimated the magnitude of unreported damages to be between 8.6 and 18.3 million m3/year.
Living plants have been used for a very long time throughout the world in structures against soil erosion, as traces have been found dating back to the first century BC. Widely practiced in Western ...Europe during the eighteenth and nineteenth centuries, bioengineering was somewhat abandoned in the middle of the twentieth century, before seeing a resurgence in recent times. Based on an extensive bibliography, this article examines the different forms of bioengineering techniques used in the past to manage rivers and riverbanks, mainly in Europe. We compare techniques using living material according to their strength of protection against erosion. Many techniques are described, both singly and in combination, ranging from tree planting or sowing seeds on riverbanks to dams made of fascine or wattle fences. The recent appearance of new materials has led to the development of new techniques, associated with an evolution in the perception of riverbanks.
In mammals, tooth function, and its efficiency, depends both on the mechanical properties of the food and on chewing dynamics. These aspects have rarely been studied in combination and/or at the ...intra-specific level. Here we applied 3D dental surface texture analysis to a sample of field voles (Microtus agrestis) trapped from Finnish Lapland at different seasons and localities to test for inter-population variations. We also explored intra-individual variation in chewing dynamics by analysing two facets on the second upper molars. Our results confirm that the two localities have similar environments and that the voles feed on the same items there. On the other hand, the texture data suggest that diets are seasonally variable, probably due to varying concentrations of abrasives. Lastly, the textures on the buccal facets are more isotropic and their direction deviates more from the mesial chewing direction than the lingual facets. We interpret these results as reflecting food, rather than chewing, movements, where food particles are more guided on the lingual side of the molars. This has implications for the application of dental microwear analysis to fossils: only homologous facets can be compared, even when the molar row seems to constitute a functional unit.
SUMMARY
The evolution of mammalian dentition is constrained by functional necessity and by the non‐independence of morphological structures. Efficient chewing implies coherent tooth coordination from ...development to motion, involving covariation patterns (integration) within dental parts. Using geometric morphometrics, we investigate the modular organization of the highly derived vole dentition. Integration patterns between and within the upper and lower molar rows are analyzed to identify potential modules and their origins (functional and developmental). Results support an integrated adult dentition pattern for both developmental and functional aspects. The integration patterns between opposing molar pairs suggest a transient role for the second upper and lower molars during the chewing motion. Upper and lower molar rows form coherent units but the relative integration of molar pairs is in contradiction with existing developmental models. Emphasis on the first three cusps to grow leads to a very different integration pattern, which would be congruent with developmental models. The early developmental architecture of traits is masked by later stages of growth, but may still be deciphered from the adult phenotype, if careful attention is paid to relevant features.
Tooth number in rodents is an example of reduction in evolution. All rodents have a toothless diastema lacking canine and most premolars present in most other mammals. Whereas some rodent lineages ...retained one premolar (p4), many others lost it during evolution. Recently, an ‘inhibitory cascade’ developmental model (IC) has been used to predict how the first molar (m1) influences the number and relative sizes of the following distal molars (m2 and m3). The model does not, however, consider the presence of premolars, and here we examine whether the premolar could influence and constrain molar proportions during development and evolution. By investigating a large data set of both extinct and extant rodent families over more than 40 million years, we show that the basal phenotype is characterized by the presence of premolars together with equally sized molars. More recent rodent families, with and without premolar, show more unequal molar sizes. Analysing molar areas, we demonstrated that (i) rodents harbour almost all the molar proportions known in mammals, and the IC model can explain about 80% of taxa in our data set; (ii) proportions of molars are influenced by the presence or absence of p4; and (iii) the most variable teeth in the dental row are m1 and m3, whether p4 is present or not. Moreover, m1 can represent up to half of the total molar area when p4 is absent. We hypothesize that p4 loss during evolution released the constraint on m1 development, resulting in a more variable size of m1 and thereby having an indirect effect on the evolution of the whole molar row.
In the Arctic, food limitation is one of the driving factors behind small mammal population fluctuations. Active throughout the year, voles and lemmings (arvicoline rodents) are central prey in ...arctic food webs. Snow cover, however, makes the estimation of their winter diet challenging. We analyzed the isotopic composition of ever‐growing incisors from species of voles and lemmings in northern Finland trapped in the spring and autumn. We found that resources appear to be reasonably partitioned and largely congruent with phylogeny. Our results reveal that winter resource use can be inferred from the tooth isotopic composition of rodents sampled in the spring, when trapping can be conducted, and that resources appear to be partitioned via competition under the snow.
The estimation of winter diets is challenging in small arctic mammals because the snow cover makes animals difficult to observe or trap. We analyzed the carbon and nitrogen isotopic composition from teeth of Finnish arvicoline rodents. By using a specific part of the ever‐growing incisors, we showed that it is possible to quantify the late winter diet of animals trapped in spring. Photograph of a lemming (Lemmus lemmus) taken at Kilpisjärvi, northwesternmost Finnish Lapland, on 21st May 2011 by HH. During migration, which in spring takes place during thaw, lemmings behave aggressively if they feel threatened
The precipitation occurring in a Nb-stabilized ferritic stainless steel, containing initially Nb(C, N) carbonitrides and Fe
3
Nb
3
X precipitates, was investigated during aging treatments performed ...between 923 K and 1163 K (650 °C and 890 °C) by combining different techniques, (thermoelectric power (TEP), scanning/transmission electron microscopy (SEM/TEM), and atom probe tomography (APT)), in order to determine the precipitation kinetics, the nature and morphology of the newly formed precipitates as well as the chemistry of the initial Fe
3
Nb
3
X precipitates, where X stands for C or N. The following composition was proposed for these precipitates: (Fe
0.81
Cr
0.19
)
3
(Nb
0.85
Si
0.08
Mo
0.07
)
3
(N
0.8
C
0.2
), highlighting the simultaneous presence of N and C in the precipitates. With regard to the precipitation in the investigated temperature range, two main phenomena, associated with a hardness decrease, were clearly identified: (i) the precipitation of Fe
2
Nb precipitates from the niobium initially present in solution or coming from the progressive dissolution of the Fe
3
Nb
3
X precipitates and (ii) the precipitation of the
χ
-phase at grain boundaries for longer aging times. From the TEP kinetics, a time–temperature–precipitation diagram has been proposed.
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