Reconstructing long-term human impacts on plant communities: an ecological approach based on lake sediment DNA

2015 ◽  
Vol 24 (7) ◽  
pp. 1485-1498 ◽  
Author(s):  
Johan Pansu ◽  
Charline Giguet-Covex ◽  
Gentile Francesco Ficetola ◽  
Ludovic Gielly ◽  
Frédéric Boyer ◽  
...  
2020 ◽  
Author(s):  
Mariusz Gałka ◽  
Klaus-Holger Knorr ◽  
Andrei-Cosmin Diaconu ◽  
Angelica Feurdean ◽  
Adam Hölzer ◽  
...  

<p>The Holocene climate shifts had a significant impact on the development of ombrotrophic peatland ecosystems located in various biogeographic zones. Disturbances of the plant communities at peatlands ecosystems took place also due to intensified human activities in the past several centuries, that include peat excavation, fires, as well as deposition of dust and pollutants on peatland surfaces. This merger of natural and human impacts has led to direct hydrological and biochemical disturbances that triggered changes in plant populations, e.g. often leading to the decline of some species, such as Sphagnum austinii in Great Britain.</p><p>The knowledge about the development of peatlands across mountain ranges in Europe is still poor. Determining the resilience of peatland vegetation to disturbance is an important and significant task to aid further protection and management of the entire range of ombrotrophic peatlands found in the European mountains, from destroyed or restored to pristine. We carried out high-resolution, multi-proxy studies including plant macrofossils, pollen, testate amoebae, geochemical analyses (XRF and stable carbon isotopes), micro- and macro-charcoal, supported by radiocarbon dating, on replicate peat cores from five well-preserved ombrotrophic peatlands across Europe where peat-forming process is active. The studied peatlands are located along an east west gradient in the Central and Western Europe: Eastern Carpathian Mts. (Calimani-Gurghiu-Harghita, Romania; Bieszczady, Poland), Harz Mts. and Schwarzwald Mts. (Germany), and Vosges Mts (France). In our palaeocological studies we aimed to: i) reconstruct long-term local (mainly Sphagnum populations) and regional (forest communities) vegetation changes at and around selected bogs; ii) reconstruct long-term palaeohydrological shifts; iii) assess mountain peatland ecosystems resilience to Holocene climate shifts and disturbance by fire events and human impact (deforestation, dust and pollution).</p><p>Based on our results, we found that: i) despite human activites (pollutants and dust deposition, drainage) some of the mountain peatlands remained in a pristine state, however some plant communities had changed; ii) plant communities composed mainly by Sphagnum species, could repeatedly self-regenerate via autogenic processes following a decline in stressors; iii) recent climate warming has stimulated the spreading of some species indicative of more dry habitats; vi) lack of macrocharcoal in the peat layers indicate that fires did not play a significant role in the development or evolution of local peatland communities. Results from our studies show that palaeoecological records play an important role for the determination of present peatland ecosystem stage and reference conditions for the restoration of damaged ombrotrophic peatlands in European mountains.</p><p>The research has received support National Science Centre (Poland) grant No UMO-2016/23/B/ST10/00762 (PI: Mariusz Gałka).</p>


2012 ◽  
pp. 66-77 ◽  
Author(s):  
I. A. Lavrinenko ◽  
O. V. Lavrinenko ◽  
D. V. Dobrynin

The satellite images show that the area of marshes in the Kolokolkova bay was notstable during the period from 1973 up to 2011. Until 2010 it varied from 357 to 636 ha. After a severe storm happened on July 24–25, 2010 the total area of marshes was reduced up to 43–50 ha. The mean value of NDVI for studied marshes, reflecting the green biomass, varied from 0.13 to 0.32 before the storm in 2010, after the storm the NDVI decreased to 0.10, in 2011 — 0.03. A comparative analysis of species composition and structure of plant communities described in 2002 and 2011, allowed to evaluate the vegetation changes of marshes of the different topographic levels. They are fol­lowing: a total destruction of plant communities of the ass. Puccinellietum phryganodis and ass. Caricetum subspathaceae on low and middle marches; increasing role of halophytic species in plant communities of the ass. Caricetum glareosae vic. Calamagrostis deschampsioides subass. typicum on middle marches; some changes in species composition and structure of plant communities of the ass. Caricetum glareosae vic. Calamagrostis deschampsioides subass. festucetosum rubrae on high marches and ass. Parnassio palustris–Salicetum reptantis in transition zone between marches and tundra without changes of their syntaxonomy; a death of moss cover in plant communities of the ass. Caricetum mackenziei var. Warnstorfia exannulata on brackish coastal bogs. The possible reasons of dramatic vegetation dynamics are discussed. The dating of the storm makes it possible to observe the directions and rates of the succession of marches vegetation.


Plants ◽  
2021 ◽  
Vol 10 (5) ◽  
pp. 990
Author(s):  
Javier Pérez-Hernández ◽  
Rosario G. Gavilán

The study of ecological succession to determine how plant communities re-assemble after a natural or anthropogenic disturbance has always been an important topic in ecology. The understanding of these processes forms part of the new theories of community assembly and species coexistence, and is attracting attention in a context of expanding human impacts. Specifically, new successional studies provide answers to different mechanisms of community assemblage, and aim to define the importance of deterministic or stochastic processes in the succession dynamic. Biotic limits, which depend directly on biodiversity (i.e., species competition), and abiotic filtering, which depends on the environment, become particularly important when they are exceeded, making the succession process more complicated to reach the previous disturbance stage. Plant functional traits (PFTs) are used in secondary succession studies to establish differences between abandonment stages or to compare types of vegetation or flora, and are more closely related to the functioning of plant communities. Dispersal limitation is a PFT considered an important process from a stochastic point of view because it is related to the establishing of plants. Related to it the soil seed bank plays an important role in secondary succession because it is essential for ecosystem functioning. Soil compounds and microbial community are important variables to take into account when studying any succession stage. Chronosequence is the best way to study the whole process at different time scales. Finally, our objective in this review is to show how past studies and new insights are being incorporated into the basis of classic succession. To further explore this subject we have chosen old-field recovery as an example of how a number of different plant communities, including annual and perennial grasslands and shrublands, play an important role in secondary succession.


Harmful Algae ◽  
2021 ◽  
Vol 101 ◽  
pp. 101971
Author(s):  
William O. Hobbs ◽  
Theo W. Dreher ◽  
Edward W. Davis ◽  
Rolf D. Vinebrooke ◽  
Siana Wong ◽  
...  

Koedoe ◽  
2008 ◽  
Vol 50 (1) ◽  
Author(s):  
Robert F. Brand ◽  
Pieter J. Du Preez ◽  
Leslie R. Brown

Within the Platberg area and the wider Drakensberg region, the shrinking natural resources and the threat posed to biodiversity are of concern to conservation management and require an understanding of long-term ecological processes. The vegetation of Platberg was investigated as part of an ecological survey to establish Afromontane floristic links to the Drakensberg as well as for the management of natural resources. From a TWINSPAN classification, refined by the Braun-Blanquet method, four main plant communities were identified, which were subdivided into fynbos, wetland, a woody/shrub community and grassland. A classification and description of the fynbos are presented in this article.The analysis showed the fynbos divided into two communities comprising four sub-communities and seven variants. The fynbos community had an average of 28.34 species per relevé, ranging from 14 to 54 species per sample plot. Twenty-four endemic or near-endemic Drakensberg Alpine Centre (DAC) species and 22 exotic (alien-invasive) species were recorded. Numerous floristic links with the DAC, Cape flora fynbos and grassland bioregions to the north and west were also found. The description of the fynbos plant communities can serve as a basis for the formulation of management plans for the area.


2014 ◽  
Vol 94 (1) ◽  
pp. 33-39 ◽  
Author(s):  
D. J. Thompson ◽  
W. D. Willms

Thompson, D. J. and Willms, W. D. 2014. Effects of long-term protection from grazing on phenotypic expression in geographically separated mountain rough fescue populations. Can. J. Plant Sci. 94: 33–39. Whether or not long-term grazing or protection from grazing alters the genetic makeup of grass populations has been debated. Mountain rough fescue [(Festuca campestris (Rydb.)], which is highly sensitive to summer grazing, and becomes dominant in plant communities with long-term protection, was chosen to address this question. Plants from three geographic sites (Stavely in AB, Milroy in the Kootenay trench, BC and Goose Lake on the BC interior plateau) with divergent grazing histories were vegetatively propagated from tillers. Daughter plants were planted into two field nurseries (at Kamloops, BC, and Stavely, AB) and morphological measurements were taken in two field seasons post-establishment. Plants from all three populations were taller, flowered earlier, and were more productive at the Kamloops nursery site. Of the three geographic sources, plants from the Goose Lake site were most distinct with narrower leaves, later flowering, and greater yield. Plants with a long history of grazing had slightly shorter fertile tillers and leaves than plants with a history of long-term protection.


Koedoe ◽  
2004 ◽  
Vol 47 (2) ◽  
Author(s):  
G. Cleaver ◽  
L.R. Brown ◽  
G.J. Bredenkamp

The Kammanassie Mountain is a declared mountain catchment area and a Cape mountain zebra Equus zebra zebra population is preserved on the mountain. The high number of springs on the mountain not only provides water for the animal species but also contributes to overall ecosystem functioning. Long-term conservation of viable ecosystems requires a broader understanding of the ecological processes involved. It was therefore decided that a classification, description and mapping of the spring vegetation of the Kammanassie Mountain be undertaken. A TWINSPAN classification, refined by Braun-Blanquet procedures, revealed 11 major plant communities that could be related to geological origin. Habitat factors associated with differences in vegetation include topography, soil type and grazing. Descriptions of the plant communities include diagnostic species as well as prominent and less conspicuous species of the tree, shrub and herbaceous layers. The results also indicate a high species richness compared to similar regions and the difference between plant communities of wet and dry springs. This data is important for long-term monitoring of the spring ecosystems as well as for the compilation of management plans.


Author(s):  
Douglas Nelson ◽  
Alan Heyvaert ◽  
Laurent Meillier ◽  
Jae Kim ◽  
Xiaoping Li ◽  
...  

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