Seasonal and landscape effects on the biotic resistance of forest communities to experimental insect introductions

2021 ◽  
Author(s):  
Brian H. Van Hezewijk ◽  
Lara van Akker ◽  
Vincent R.A. Waring
Keyword(s):  
Biotic Resistance ◽  
Forest Communities ◽  
Landscape Effects

Colonization of decomposing Sphagnum moss litter by mycorrhizal roots in two types of peatland ecosystems

2014 ◽  
Vol 10 ◽  
pp. 113-121
Author(s):  
Mateusz Wilk ◽  
Julia Pawłowska ◽  
Marta Wrzosek ◽  
Michał Gorczak ◽  
Małgorzata Suska-Malawska
Keyword(s):  
Molecular Identification ◽  
Decomposition Process ◽  
Sphagnum Moss ◽  
Forest Communities ◽  
Litter Bags ◽  
Poor Fen ◽  
The Poor ◽  
Ectomycorrhizal Roots ◽  
Mycorrhizal Roots ◽  
Ectomycorrhizal Morphotypes

During a 35-month study on the decomposition of Sphagnum moss litter in poor fen and pine bog forest, an intensive colonization of litter-bags by mycorrhizal roots was observed during the decomposition process. Content of mycorrhizal roots in litter-bags, expressed as % mass of roots, was generally increasing during the decomposition in pine bog forest, and fluctuating during decomposition on poor fen, although in both cases the results were statistically insignificant. Two morphotypes of ericoid roots and two morphotypes of ectomycorrhizal roots were recorded from litter-bags on poor fen during the decomposition experiment, while in pine bog forest one morphotype of ericoid and nine morphotypes of ectomycorrhizal roots were recorded. Molecular identification of mycorrhizal roots succeeded only in the case of one ericoid and six putatively ectomycorrhizal morphotypes. Most morphotypes were recorded only once during the whole 35-month decomposition period, and only one ericoid and one ectomycorrhizal morphotypes were shared between the poor fen and pine bog forest communities.

Vegetation structure of tundra and taiga on the map of the natural vegetation of Europe

2007 ◽  
pp. 13-22 ◽  
Author(s):  
T. K. Yurkovskaya
Keyword(s):  
Vegetation Cover ◽  
Abiotic Factors ◽  
Self Regulation ◽  
Space Structure ◽  
Middle Taiga ◽  
Russian Plain ◽  
Forest Communities ◽  
The North ◽  
Tundra Vegetation ◽  
Starting Point

I have focused only on some features of structure in the taiga vegetation cover. In conclusion I would like to tell some words about the causes of complicated space structure of the taiga and tundra vegetation cover. The causes of latitudinal differentiation are climatic undoubtedly, but heterogeneity of vegetation cover within the limits of tundra and taiga subzones is accounted for different factors. In tundra abiogenic factors prevail, first of all the permafrost processes. That is the reason why tundra vegetation cover is so sensible to any disturbances and so hard regenerates after various transformations. In taiga the space structure is mostly the result of self-regulation and self- restoration of biota. The abiotic factors, certainly, play significant role, but they recede to the second plan. So we showed that in the north and middle taiga the structure of vegetation cover, during the Holocene up to present time, is determined in many respects by the increasing role of mires. Suffice it to look at the map of distribution of mires in order to estimate their role in vegetation cover of the easteuropean taiga (Yurkovskaya, 1980). So, the increase of mire area on the Russian Plain in m2/year per 1000 ha varies between 200 and 700, the average increas is ca 300—400 m2/year (Elina et all., 2000). The mires favour peniplenization and unite the separate areas of forest communities into the whole by means of forming the buffer paludificated territories (various hydrophilous variants of forest communities). But if mires, at all their stability, after destroying practically don't restore, the forests even after continuous cuttings restore their structure and composition through the series of successional stages unless an ecotope is damaged completely. Hence the space structure of taiga is the result, first of all, self development and self regulation of its vegetation cover. But, as it is known, at present time the process of destruction of natural biota has gone too far that the question arises not only about supporting its state and structure but also about the survival of the mankind itself. In this regard the vegetation map of Europe is the invaluable basis, which gives the starting point for all conservational, ecological and economical measures. But it is important to learn reading and using the map. And this is one of our actual goals.

Langfristige Entwicklung von zwei Waldgesellschaften im Białowieża-Urwald

2008 ◽  
Vol 159 (4) ◽  
pp. 80-90 ◽  
Author(s):  
Bogdan Brzeziecki ◽  
Feliks Eugeniusz Bernadzki
Keyword(s):  
Species Composition ◽  
Tree Species ◽  
Stand Structure ◽  
Temporal Dynamics ◽  
Structural Parameters ◽  
Forest Communities ◽  
Natural Forests ◽  
Tree Species Composition ◽  
Strong Trend ◽  
Long Term Study

The results of a long-term study on the natural forest dynamics of two forest communities on one sample plot within the Białowieża National Park in Poland are presented. The two investigated forest communities consist of the Pino-Quercetum and the Tilio-Carpinetum type with the major tree species Pinus sylvestris, Picea abies, Betula sp., Quercus robur, Tilia cordata and Carpinus betulus. The results reveal strong temporal dynamics of both forest communities since 1936 in terms of tree species composition and of general stand structure. The four major tree species Scots pine, birch, English oak and Norway spruce, which were dominant until 1936, have gradually been replaced by lime and hornbeam. At the same time, the analysis of structural parameters indicates a strong trend towards a homogenization of the vertical stand structure. Possible causes for these dynamics may be changes in sylviculture, climate change and atmospheric deposition. Based on the altered tree species composition it can be concluded that a simple ≪copying≫ (mimicking) of the processes taking place in natural forests may not guarantee the conservation of the multifunctional character of the respective forests.

Planting native trees to restore riparian forests increases biotic resistance to non-native plant invasions

2021 ◽  
pp. 1-24
Author(s):  
Chad F. Hammer ◽  
John S. Gunn
Keyword(s):  
United States ◽  
Ecosystem Service ◽  
Invasive Plant ◽  
Biotic Resistance ◽  
The United States ◽  
Tree Regeneration ◽  
Tree Planting ◽  
Plant Colonization ◽  
Native Plant ◽  
Native Trees

Abstract Non-native invasive plant species are a major cause of ecosystem degradation and impairment of ecosystem service benefits in the United States. Forested riparian areas provide many ecosystem service benefits and are vital to maintaining water quality of streams and rivers. These systems are also vulnerable to natural disturbances and invasion by non-native plants. We assessed whether planting native trees on disturbed riparian sites may increase biotic resistance to invasive plant establishment in central Vermont in the northeastern United States. The density (stems/m2) of invasive stems was higher in non-planted sites (x̄=4.1 stems/m2) compared to planted sites (x̄=1.3 stems/m2). More than 90% of the invasive plants were Japanese knotweed (Fallopia japonica). There were no significant differences in total stem density of native vegetation between planted and non-planted sites. Other measured response variables such as native tree regeneration, species diversity, soil properties and soil function showed no significant differences or trends in the paired riparian study sites. The results of this case study indicate that tree planting in disturbed riparian forest areas may assist conservation efforts by minimizing the risk of invasive plant colonization.

scholarly journals Analysing landscape effects on dispersal networks and gene flow with genetic graphs

2021 ◽  
Author(s):  
Paul Savary ◽  
Jean‐Christophe Foltête ◽  
Hervé Moal ◽  
Gilles Vuidel ◽  
Stéphane Garnier
Keyword(s):  
Gene Flow ◽  
Landscape Effects
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