scholarly journals Rapid, landscape scale responses in riparian tundra vegetation to exclusion of small and large mammalian herbivores

2011 ◽  
Vol 12 (8) ◽  
pp. 643-653 ◽  
Author(s):  
Virve Tuulia Ravolainen ◽  
Kari Anne Bråthen ◽  
Rolf Anker Ims ◽  
Nigel Gilles Yoccoz ◽  
John-André Henden ◽  
...  
Keyword(s):  
Landscape Scale ◽  
Mammalian Herbivores ◽  
Tundra Vegetation

scholarly journals Interactions between large herbivores and litter removal by termites across a rainfall gradient in a South African savanna

2011 ◽  
Vol 27 (4) ◽  
pp. 375-382 ◽  
Author(s):  
Robert Buitenwerf ◽  
Nicola Stevens ◽  
Cleo M. Gosling ◽  
T. Michael Anderson ◽  
Han Olff
Keyword(s):  
Plant Biomass ◽  
Spatial Scales ◽  
Landscape Scale ◽  
Local Scale ◽  
Arid Ecosystems ◽  
Annual Rainfall ◽  
Large Herbivores ◽  
Mammalian Herbivores ◽  
Litter Removal ◽  
Semi Arid

Abstract:Litter-feeding termites influence key aspects of the structure and functioning of semi-arid ecosystems around the world by altering nutrient and material fluxes, affecting primary production, foodweb dynamics and modifying vegetation composition. Understanding these complex effects depends on quantifying spatial heterogeneity in termite foraging activities, yet such information is scarce for semi-arid savannas. Here, the amount of litter that was removed from 800 litterbags in eight plots (100 litterbags per plot) was measured in Hluhluwe–iMfolozi Park (HiP) South Africa. These data were used to quantify variation in litter removal at two spatial scales: the local scale (within 450-m2 plots) and the landscape scale (among sites separated by 8–25 km). Subsequently, we attempted to understand the possible determinants of termites’ foraging patterns by testing various ecological correlates, such as plant biomass and bare ground at small scales and rainfall and fences that excluded large mammalian herbivores at larger scales. No strong predictors for heterogeneity in termite foraging intensity were found at the local scale. At the landscape scale termite consumption depended on an interaction between rainfall and the presence of large mammalian herbivores: litter removal by termites was greater in the presence of large herbivores at the drier sites but lower in the presence of large herbivores at the wetter sites. The effect of herbivores on termite foraging intensity may indicate a switch between termites and large herbivore facilitation and competition across a productivity gradient. In general, litter removal decreased with increasing mean annual rainfall, which is in contrast to current understanding of termite consumption across rainfall and productivity gradients. These results generate novel insights into termite ecology and interactions among consumers of vastly different body sizes across spatial scales.

Landscape-Scale Restoration of the Longleaf Pine Ecosystem

1998 ◽  
Vol 16 (1) ◽  
pp. 41-45
Author(s):  
Rhett Johnson ◽  
Dean Gjerstad
Keyword(s):  
Longleaf Pine ◽  
Landscape Scale

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.

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