scholarly journals Impacts of Land-Use Changes on Vegetation and Ecosystem Functioning: Old-Field Secondary Succession

Plants ◽  
2021 ◽  
Vol 10 (5) ◽  
pp. 990
Author(s):  
Javier Pérez-Hernández ◽  
Rosario G. Gavilán
Keyword(s):  
Plant Communities ◽  
Ecosystem Functioning ◽  
Secondary Succession ◽  
Species Coexistence ◽  
Human Impacts ◽  
Soil Seed Bank ◽  
Land Use Changes ◽  
Dispersal Limitation ◽  
Point Of View ◽  
Old Field

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.

Impact of agrarian practices and some pastoral uses on vegetation in Algerian steppe rangelands

2019 ◽  
Vol 41 (2) ◽  
pp. 97
Author(s):  
R. F. Hammouda ◽  
J. Huguenin ◽  
L. Julien ◽  
D. Nedjraoui
Keyword(s):  
Land Use ◽  
20Th Century ◽  
Plant Communities ◽  
General Trend ◽  
Human Impacts ◽  
Land Use Changes ◽  
Herd Size ◽  
Study Zone ◽  
Considerable Impact ◽  
Biophysical Environment

The decline in steppe vegetation in Algeria was first reported in the mid-20th century, and for many years was attributed to recurrent droughts. Hypotheses suggesting that this decline was a consequence of human activities emerged in the 1970s – a time of major socioeconomic trends in the region. Changes such as strong population growth, sedentarisation, herd size increases and use of pasture land for crops, all had considerable impact on rangeland vegetation. The aim of the present work was to identify heterogeneity in the pasture vegetation of a given ‘territory’ (in the sense of a ‘terroir’), or biophysical environment (including meteorological), taking into account rangeland distribution, land use changes and herd management in the Aflou region of Algeria. Characterisation and mapping of the vegetation and its environment in the study area led to the hypothesis that, apart from some very slight soil differences, heterogeneity in rangeland vegetation appeared mainly related to human impacts. Bertin’s Semiology of Graphics was used to analyse the results, and indicated a major decline in vegetation productivity and biodiversity in the steppe rangelands of the study zone. Beyond this general trend in the municipal territory studied, areas were found with contrasting flora communities, with some showing relatively stable plant communities, while other areas had some plant communities that had undergone regressive succession. Grazing conditions and the proximity of ploughed land were responsible for these different vegetation situations.

Reed (Phragmites australis agg.) dominated plant communities in the Lower Volga Valley

2015 ◽  
pp. 26-37
Author(s):  
V. B. Golub ◽  
V. V. Bondareva ◽  
A. N. Sorokin ◽  
L. F. Nikolaychuk
Keyword(s):  
Expert System ◽  
Phragmites Australis ◽  
Plant Communities ◽  
Floristic Composition ◽  
Original Data ◽  
Optimal Level ◽  
Point Of View ◽  
Original Structure ◽  
Volga River ◽  
Lower Volga

Plant communities with reed domination (Phragmites australis agg.) occupy the large areas in the Lower Volga Valley and especially in the river delta. We have set the task to reveal the diversity of these communities in the Lower Volga Valley. For this purpose, we applied the database that is registered in the Global Index of Vegetation-Plot Databases (GIVD) under the EU-RU–002 index (http://www.givd.info/) and includes 14871 relevés made during the period from 1924 to 2013. Communities with the dominance of reed were defined as such, if the coverage of this plant was more than 50 %. We have found 375 such relevés in the database. At first, one basal community, 3 associations and 3 subassociations with domination of Phragmites australis agg. were distinguished in the Lower Volga Valley. All processing and analysis of relevés were performed using the software package JUICE 7.0. (Tichý, 2002). The «Cocktail» method was applied to establish the sociological groups that indicate environmental conditions (Bruelheide, 2000). The expert system for selection from the database of relevés by means of these groups was created. It is allowed us to ascribe relevés to earlier distinguished associations, subassociations and basal community. 171 relevés have been identified by the expert system and they were assigned to association, subassociation or the basal community. 204 relevés were not referred to any association, subassociation or the basal community. We wanted to answer the question: are there among these 204 relevés, which could be interpreted as the new syntaxa, giving them the proper ecological characteristics? For this purpose, the cluster analysis of 204 relevés has been carried out. The optimal level of clustering was determined by calculating the index of “crispness of classification” (Botta-Dukát et al., 2005). The greatest “crispness of classification” was reached at allocation of 13 clusters. Consideration of the floristic composition of allocated groups had shown that 11 of them were the transitional plant communities among the earlier established syntaxa. Only two clusters were differed in rather original structure that we could explain by the influence of environment factors. We have identified them as new associations Rubio tataricae-Phragmitetum australis and Cynancho acuti-Phragmitetum australis. All associations with the dominance of Phragmites australis agg. distinguished in the Lower Volga Valley were included in the alliance Phragmition communis Koch 1926, order Phragmitetalia communis Koch 1926. In literary sources from the ecological point of view these syntaxa are defined as the wetland communities, which are closely linked to water bodies (Šumberová et al., 2011; Ermakov, 2012). However, in many cases this definition does not correspond to the ecology of plant communities with the dominance of reed in the lower reaches of the Volga River. Ecotops of these communities are flooded for up to 2–3 months in a year and then they dry out. In the autumn, the ground water level can drop to a depth of one meter (Golub et al., 2011). The plant satellites of the reed here are often mesophytic plants such as Rubus caesius, Calamagrostis epigeios, Phalaris arundinacea, Rubia tatarica, Althaea officinalis, and Rumex stenophyllus. Therefore, the inclusion of phytocoenosises with domination of the reed in the lower reaches of the Volga River in the alliance Phragmition communis is rather relative. A correct placement of these plant communities in the system of vegetation syntaxa of the arid areas can be made only if it is based on original data obtained from much bigger territory than the Lower Volga Valley. In future geobotanical studies, it is desirable to divide the aggregation of Phragmites australis agg. into smaller species taxa.

An ecological look at saline wetlands

2004 ◽  
Vol 52 (1) ◽  
pp. 37-44
Author(s):  
M. Shokri ◽  
N. Safaian ◽  
M. Z. Ahmadi
Keyword(s):  
Plant Species ◽  
Water Table ◽  
Plant Communities ◽  
Sustainable Use ◽  
Point Of View ◽  
Ecological Niches ◽  
Salicornia Europaea ◽  
The Caspian Sea ◽  
Aeluropus Littoralis ◽  
Natural Equilibrium

Due to the occurrence of considerable areas of wetlands in the world, the wise, sustainable use of these lands is one of major importance for ecologists and agriculturists. As the presence of indicator species and plant communities can be a measure of the compatibility between plants and edaphic conditions in these regions, the ecological niches of plant species in part of the southern coastal areas of the Caspian Sea have been studied to show the correlation of each species with its own habitat. The plant communities were separated with Ward's cluster analysis. The correlation of these communities and plant species with environmental factors was investigated with the CCA method, using PC-Ordination-4 software. The results showed that the soil EC, water table, soil pH, SAR and ESP were 14-157 dS/m, 0-240 cm, 6.5-8.5, 13.4-84.8 and 2-55%, respectively. This range of values, in addition to creating ecological niches for species with different ecological roles, was also effective in the formation of plant communities. The analysis of vegetation and soil data with the CCA method showed the relationships between soil factors and vegetation. In spite of the dominance of the species Halocnemum strobilaceum in all the plant communities, the correlation of this species with plant species such as Aeluropus littoralis, Salicornia europaea, Aeluropus lagopoides,Salsola aurantia and Puccinella distans in relation to changes in EC, water table, pH, SAR and ESP, is important from the point of view of sustaining the physical environment and ecological function. The simplification of these ecosystems (by drainage, agriculture, etc.) may disturb the natural equilibrium. As these ecosystems are susceptible and changes in their use are costly from the ecological and economic points of view, the wise use of ecosystems in their natural forms (rangelands and habitats) is recommended to prevent the spread of salinity and to protect habitats and biodiversity.

scholarly journals The Past, Present, and Future of Tuna at Lake Moāwhitu: Drawing on the two knowledge baskets of Mātauranga Māori and Western Science

2021 ◽  
Author(s):  
Russleigh Parai
Keyword(s):  
Algal Blooms ◽  
Human Impacts ◽  
Anthropogenic Impacts ◽  
Land Use Changes ◽  
Environmental Dna ◽  
Western Science ◽  
Lake Water Quality ◽  
Dna Metabarcoding ◽  
Remedial Intervention ◽  
Life Force

<p><b>Knowledge generated through experience and understanding relies on the senses, one of which is listening. This thesis provides an opportunity to hear the diminishing voice of tuna utilizing paleolimnological techniques and our natural senses through traditional Indigenous methodologies in order to track the presence of tuna back in time. </b></p> <p>This study provides historical environmental context of Lake Moāwhitu catchment (Rangitoto ki te Tonga) as a once significant mahinga kai site for manawhenua, Ngāti Koata. The strong connection to place is not lost on Ngāti Koata despite for many their geographic detachment to their turangawaewae. They hear the voice of tuna calling them back to sustain them as they have sustained Māori from the beginning of time. Now considered wāhi tapu due to significant degradation, Moāwhitu is currently undergoing remedial intervention by Ngāti Koata, DoC, Lakes380 and stakeholders to restore the mauri (life force) of the Lake and adjacent wetland ecosystem.</p> <p>Drawing from two distinct knowledge streams of western science and mātauranga Māori, this study draws new (on-site) understandings about the anthropogenic impacts on tuna as well as their status and relationship as tuākana (older sibling) to Māori. Through this journey a ‘te ao Māori’ (Māori worldview) is explored, revealing a historically healthy and abundant tuna population and thriving tuākana-teina relationship up until recent decades. This information complements the environmental reconstruction derived from western science methods applied to a lake Moawhitu sediment core spanning the last 1000 years or so. Through a combination of palynology, hyperspectral scanning and bacterial environmental DNA metabarcoding, it is clear that lake water quality remained high despite various historical land cover and land use changes, until recent decades when deteriorating quality has accompanied a rise in cyanobacteria and toxic algal blooms. These changes appear to coincide with intensified pastoralism accompanying draining of the lake and fringing wetlands since the mid-twentieth century. How tuna have endured these recent human impacts and why their survival and sustainability is important to Aotearoa today is at the heart of this thesis which seeks to explore how two vastly different knowledge streams converge and navigate unchartered waters. The two knowledge baskets (with their respective world views) are held up for the reader to view and consider what an effective collaborative partnership looks like by recognising basic intrinsic values of respect, reciprocity and kindness. The challenge remains to draw out the very best of people (he tangata) as a way to bring about urgent regenerative solutions for our tuākana, tuna, and in turn humanity itself.</p>

scholarly journals Landscape typology in Czechia and abroad: State of the art, methods and theoretical basis

Geografie ◽  
2007 ◽  
Vol 112 (1) ◽  
pp. 61-83
Author(s):  
Zdeněk Lipský ◽  
Dušan Romportl
Keyword(s):  
Land Use ◽  
Theoretical Basis ◽  
State Of The Art ◽  
Human Impacts ◽  
Land Use Changes ◽  
European Countries ◽  
Intensive Agriculture ◽  
European Landscape Convention ◽  
Character Assessment ◽  
Landscape Character

The main goal of this paper is to introduce the importance of landscape typology in present times when many landscapes are exposed to dynamic human impacts such as land use changes, urbanization, intensive agriculture, forestry or industrialization. Different approaches to landscape typology in Czechia and other European countries as well as relations of landscape typology to landscape character assessment and the European Landscape Convention are discussed. A requirement of a new exact and applicable landscape typology is a great challenge for Czech geographers.

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