Long‐term exclosure of sheep‐grazing from an ancient wood: Vegetation change after a sixty‐year experiment

2020 ◽  
Author(s):  
Ondřej Vild ◽  
Ian Douglas Rotherham
Keyword(s):  
Vegetation Change ◽  
Sheep Grazing ◽  
Ancient Wood

A quantitative synthesis of Holocene vegetation change in Nigeria (Western Africa)

The Holocene ◽  
2021 ◽  
pp. 095968362110331
Author(s):  
Matthew Adesanya Adeleye ◽  
Simon Edward Connor ◽  
Simon Graeme Haberle
Keyword(s):  
Vegetation Change ◽  
Climatic Changes ◽  
The Holocene ◽  
Continental Scale ◽  
Western Africa ◽  
Chord Distance ◽  
Quantitative Synthesis ◽  
Climatic Regime ◽  
Pollen Records

Understanding long-term (centennial–millennial scale) ecosystem stability and dynamics are key to sustainable management and conservation of ecosystem processes under the currently changing climate. Fossil pollen records offer the possibility to investigate long-term changes in vegetation composition and diversity on regional and continental scales. Such studies have been conducted in temperate systems, but are underrepresented in the tropics, especially in Africa. This study attempts to synthesize pollen records from Nigeria (tropical western Africa) and nearby regions to quantitatively assess Holocene regional vegetation changes (turnover) and stability under different climatic regimes for the first time. We use the squared chord distance metric (SCD) to assess centennial-scale vegetation turnover in pollen records. Results suggest vegetation in most parts of Nigeria experienced low turnover under a wetter climatic regime (African Humid Period), especially between ~8000 and 5000 cal year BP. In contrast, vegetation turnover increased significantly under the drier climatic regime of the late-Holocene (between ~5000 cal year BP and present), reflecting the imp role of moisture changes in tropical west African vegetation dynamics during the Holocene. Our results are consistent with records of vegetation and climatic changes in other parts of Africa, suggesting the Holocene pattern of vegetation change in Nigeria is a reflection of continental-scale climatic changes.

scholarly journals Vegetation change (1988–2010) in Camdeboo National Park (South Africa), using fixed-point photo monitoring: The role of herbivory and climate

Koedoe ◽  
2013 ◽  
Vol 55 (1) ◽  
Author(s):  
Mmoto L. Masubelele ◽  
Michael T. Hoffman ◽  
William Bond ◽  
Peter Burdett
Keyword(s):  
South Africa ◽  
Fixed Point ◽  
National Parks ◽  
Vegetation Cover ◽  
National Park ◽  
Vegetation Change ◽  
Growth Form ◽  
Annual Rainfall ◽  
Management Interventions

Fixed-point photo monitoring supplemented by animal census data and climate monitoring potential has never been explored as a long-term monitoring tool for studying vegetation change in the arid and semi-arid national parks of South Africa. The long-term (1988–2010), fixed-point monitoring dataset developed for the Camdeboo National Park, therefore, provides an important opportunity to do this. Using a quantitative estimate of the change in vegetation and growth form cover in 1152 fixed-point photographs, as well as series of step-point vegetation surveys at each photo monitoring site, this study documented the extent of vegetation change in the park in response to key climate drivers, such as rainfall, as well as land use drivers such as herbivory by indigenous ungulates. We demonstrated the varied response of vegetation cover within three main growth forms (grasses, dwarf shrubs [< 1 m] and tall shrubs [> 1 m]) in three different vegetation units and landforms (slopes, plains, rivers) within the Camdeboo National Park since 1988. Sites within Albany Thicket and Dwarf Shrublands showed the least change in vegetation cover, whilst Azonal vegetation and Grassy Dwarf Shrublands were more dynamic. Abiotic factors such as drought and flooding, total annual rainfall and rainfall seasonality appeared to have the greatest influence on growth form cover as assessed from the fixed-point photographs. Herbivory appeared not to have had a noticeable impact on the vegetation of the Camdeboo National Park as far as could be determined from the rather coarse approach used in this analysis and herbivore densities remained relatively low over the study duration.Conservation implications: We provided an historical assessment of the pattern of vegetation and climatic trends that can help evaluate many of South African National Parks’ biodiversity monitoring programmes, especially relating to habitat change. It will help arid parks in assessing the trajectories of vegetation in response to herbivory, climate and management interventions.

Recruitment patterns following a severe drought: long-term compositional shifts in Patagonian forests

2008 ◽  
Vol 38 (12) ◽  
pp. 3002-3010 ◽  
Author(s):  
María L. Suarez ◽  
Thomas Kitzberger
Keyword(s):  
Vegetation Change ◽  
Forest Canopy ◽  
Tree Mortality ◽  
Forest Composition ◽  
Future Climate Change ◽  
Severe Drought ◽  
Climate Change Scenarios ◽  
Recruitment Pattern ◽  
Recruitment Patterns

Severe droughts have the potential of inducing transient shifts in forest canopy composition by altering species-specific adult tree mortality patterns. However, permanent vegetation change will occur only if tree recruitment patterns are also affected. Here, we analyze how a massive mortality event triggered by the 1998–1999 drought affected adult and sapling mortality and recruitment in a mixed Nothofagus dombeyi (Mirb.) Blume – Austrocedrus chilensis (D. Don) Flor. et Boult. forests of northern Patagonia. Comparing drought-induced and tree-fall gaps, we assessed changes in forest composition, microenvironments, and seedling density and survival of both species. Drought-kill disturbance shifted species composition of both canopy and sapling cohorts in favour of A. chilensis. Drought gaps were characterized by a shadier and more xeric environment, affecting the recruitment pattern of N. dombeyi seedlings. The seedling cohort was composed mostly of A. chilensis, and its survival was always higher than that of N. dombeyi. Additionally, A. chilensis seedlings showed higher plasticity than N. dombeyi seedlings, increasing its root to shoot ratios in drought gaps. The results suggest that extreme drought itself is a strong driving force in forest dynamics, with important imprints on forest landscapes. Future climate-change scenarios, projecting an increased in frequency and severity of droughts, alert us about expected long-term compositional shifts in many forest ecosystems.

scholarly journals Landscape Change and Trade in Ancient Greece: Evidence from Pollen Data

2020 ◽  
Vol 130 (632) ◽  
pp. 2596-2618
Author(s):  
Adam Izdebski ◽  
Tymon Słoczyński ◽  
Anton Bonnier ◽  
Grzegorz Koloch ◽  
Katerina Kouli
Keyword(s):  
Environmental History ◽  
Agricultural Production ◽  
Landscape Change ◽  
Vegetation Change ◽  
Structural Changes ◽  
Ancient Greece ◽  
Pollen Data ◽  
Trade Expansion ◽  
Southern Greece

Abstract In this article we use pollen data from six sites in southern Greece to study long-term vegetation change in this region from 1000 BCE to 600 CE. Based on insights from environmental history, we interpret our estimated trends in the regional presence of cereal, olive and vine pollen as proxies for structural changes in agricultural production. We present evidence that there was a market economy in ancient Greece and a major trade expansion several centuries before the Roman conquest. Our results are consistent with auxiliary data on settlement dynamics, shipwrecks and ancient oil and wine presses.

Differential responses of heather and red grouse to long-term spatio-temporal variation in sheep grazing

2020 ◽  
Vol 29 (8) ◽  
pp. 2689-2710
Author(s):  
Sonja C. Ludwig ◽  
Nicholas J. Aebischer ◽  
Michael Richardson ◽  
Staffan Roos ◽  
Des B. A. Thompson ◽  
...  
Keyword(s):  
Temporal Variation ◽  
Sheep Grazing ◽  
Red Grouse ◽  
Differential Responses ◽  
Spatio Temporal

scholarly journals Release from sheep‐grazing appears to put some heart back into upland vegetation: A comparison of nutritional properties of plant species in long‐term grazing experiments

2020 ◽  
Vol 177 (1) ◽  
pp. 152-162 ◽  
Author(s):  
Robert H. Marrs ◽  
HyoHyeMi Lee ◽  
Sabena Blackbird ◽  
Leslie Connor ◽  
Susan E. Girdwood ◽  
...  
Keyword(s):  
Plant Species ◽  
Sheep Grazing ◽  
Nutritional Properties
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