Typical Vegetation Types Research Articles

Vegetation of the Stipa loess steppe in Ningxia (northern China) in relation to grazing intensity

AbstractLarge areas of northern and western China are covered with steppe vegetation which is grazed with different intensities. Areas which are not or only slightly grazed are rare and mostly exist in nature reserves. We investigated floristic composition and species diversity of the steppe vegetation of the autonomous region Ningxia Hui with emphasis on the Yunwushan dry steppe nature reserve in relation to grazing intensity; all 77 plots were analyzed using ordination techniques, and the relationship between the variation in species composition and environmental conditions was analyzed. In Ningxia, two types of loess grass steppes prevail: in areas with lower altitudes from approximately 1650–1950 m a.s.l., the Stipa bungeana steppe occurs whereas the Stipa grandis steppe is typical for higher altitudes between 1900 and 2100 m a.s.l. For both vegetation types, three subtypes can be distinguished according to different levels of grazing intensity. With increasing grazing intensity, the number of plant species per plot strongly declines and the typical steppe vegetation types are dominated by Artemisia species (A. frigida in the Stipa grandis community and A. sacrorum in the Stipa bungeana community). In contrast to studies carried out in neighboring areas, in our study area the Artemisia steppes do not represent the final state of degradation. Instead, Convolvulus ammanii dominates in heavily grazed areas of both Stipa steppe types. Detrended correspondence analysis confirms the classification and shows that the heavily grazed subtypes of the Stipa grandis and the Stipa bungeana steppe with Convolvulus ammanii are more similar to each other than the other vegetation types. The first axis of the detrended correspondence analysis is strongly related to the grazing intensity (r = 0.93). Our results show that grazing intensity is an important factor for the differentiation of the steppe grasslands and a severe threat to species diversity.

Simulation of maximum light use efficiency for some typical vegetation types in China

Maximum light use efficiency (emax) is a key parameter for the estimation of net primary productivity (NPP) derived from remote sensing data. There are still many divergences about its value for each vegetation type. The emax for some typical vegetation types in China is simulated using a modified least squares function based on NOAA/AVHRR remote sensing data and field-observed NPP data. The vegetation classification accuracy is introduced to the process. The sensitivity analysis of emax to vegetation classification accuracy is also conducted. The results show that the simulated values of emax are greater than the value used in CASA model, and less than the values simulated with BIOME-BGC model. This is consistent with some other studies. The relative error of emax resulting from classification accuracy is −5.5%–8.0%. This indicates that the simulated values of emax are reliable and stable.

Use of balloon aerial photography for classification of Kushiro wetland vegetation, northeastern Japan

Kushiro wetland in northeastern Japan is a Ramsar-designated wetland of international importance (1980) that is characterized by high biodiversity and spatial heterogeneity. These characteristics of the wetland also present innumerable challenges for mapping and monitoring such unique ecosystems. Recent advances in remote sensing technology have provided many sensors with different spatial and spectral scales and resolutions. However, they are still inadequate for mapping wetland vegetation at a large scale for various reasons, such as inadequate resolution and high costs. This study was designed to evaluate the potential of balloon aerial photography to acquire high resolution (15 cm pixel size) imagery for mapping wetland vegetation in the Akanuma marsh. We used a standard 28-mm non-metric camera (Nikon-F-801), which seven specific categories (species mixes) were successfully delineated. It was possible to classify small shrubs mixed with herbaceous plants; moss bogs with pools; dwarf shrubs with sedges; and moss with alpine plants. From this research, it seems that balloon aerial photography is a powerful tool for mapping temperate wetland vegetation, allowing classification of specific and typical vegetation types to the genus and species level.

Perspective article: Simulation models for semi‐arid rangelands of southern Africa

In semi‐arid regions, the effects of grazing or sparing management on natural communities of long‐lived plants generally take decades to become evident. Event‐driven dynamic behaviour, unpredictable and low rainfall, and complicated interactions between species make it difficult to gather sufficient understanding of vegetation dynamics to be able to develop guidelines for sustainable management. Simulation models that consider the essential processes that determine vegetation dynamics offer scope for quantitatively exploring long‐term vegetation dynamics of arid and semi‐arid rangelands. In this paper we review three models that were aimed to provide an understanding of the vegetation dynamics and management of different typical vegetation types in South Africa, including the Karoo shrubland, the shrub‐grassland of the southern Kalahari, and pure semi‐arid grasslands.

The relationship between the climates, ecology and plant geography of the southern cold temperate zone and of the tropical high mountains

This asymmetry of the two hemispheres may be demonstrated by drawing a profile-diagram of the climatic vegetation belts from the northern to the southern polar regions, or by constructing a ‘summarized continent’ (i.e. a world map showing the proportions of land and sea in the different latitudes of the globe). The typical boreal vegetation types—tundra, coniferous forests and caducous broadleaved forests—are restricted to the continental, winter-cold climates of North America and Eurasia, while in the high-oceanic cold temperate zone of the southern hemisphere tussock grasslands, communities with cushion plants, and luxuriant evergreen scrubs and forests exist. The cool-temperate forests of Patagonia and New Zealand have a striking similarity to the upper montane forests of tropical mountains (Ceja de la Montaña of the Andes; moss-forests, and elfin forests of East Africa and Malaysia). Similarly the tussock grasslands of the subantarctic have their counterparts in the tussock and cushion formations of equatorial high mountains (páramos). The same arrangement of zones may be observed vertically, between lowlands and mountains, in New Guinea, as is encountered when proceeding from north to south at one level in New Zealand. In each case the succession passes from tropical rainforests through lower montane forests with Weinmannia, Podocarpus and Nothofagus to upper montane forests with Libocedrus and Dacrydium and then to tussock grassland with Danthonia (Troll 1947). These contrasts and similarities can be correlated clearly with temperature conditions, and this is best illustrated by comparing so-called thermoisopleth diagrams for Macquarie Island, Quito, McMurdo Sound (Antarctica) and Oxford.