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Bank Composition (bank + composition)
Kinds of Bank Composition Selected AbstractsFlooding, soil seed bank dynamics and vegetation resilience of a hydrologically variable desert floodplainFRESHWATER BIOLOGY, Issue 2 2006SAMANTHA J. CAPON Summary 1. This paper explores soil seed bank composition and its contribution to the vegetation dynamics of a hydrologically variable desert floodplain in central Australia: the Cooper Creek floodplain. We investigated patterns in soil seed bank composition both temporally, in response to flooding (and drying), and spatially, with relation to flood frequency. Correlations between extant vegetation and soil seed bank composition are explored with respect to flooding. 2. A large and diverse germinable soil seed bank was detected comprising predominantly annual monocot and annual forb species. Soil seed bank composition did not change significantly in response to a major flood event but some spatial patterns were detected along a broad flood frequency gradient. Soil seed bank samples from frequently flooded sites had higher total germinable seed abundance and a greater abundance of annual monocots than less frequently flooded sites. In contrast, germinable seeds of perennial species belonging to the Poaceae family were most abundant in soil seed bank samples from rarely flooded sites. 3. Similarity between the composition of the soil seed bank and extant vegetation increased following flooding and was greatest in more frequently flooded areas of the floodplain, reflecting the establishment of annual species. The results indicate that persistent soil seed banks enable vegetation in this arid floodplain to respond to unpredictable patterns of flooding and drying. [source] The resilience of calcareous and mesotrophic grasslands following disturbanceJOURNAL OF APPLIED ECOLOGY, Issue 3 2005RACHEL A. HIRST Summary 1Understanding habitat disturbance and recovery is vital for successful conservation management and restoration, particularly of subseral communities with high nature conservation interest and sites subject to unavoidable disturbance pressures, such as that arising from access and recreational activities. 2Grassland resilience was investigated on the Salisbury Plain Training Area (SPTA) in southern England, the largest of the UK military training areas. SPTA contains the greatest expanse of unimproved chalk grassland in north-west Europe, a habitat of particular nature conservation interest. 3Historical aerial photographs were used to identify 82 calcareous and mesotrophic grassland sites disturbed over a 50-year time period. Vegetation, soils and seed bank data were collected from each old disturbance site. Revegetation time periods following disturbance were compared, and habitat resilience following disturbance investigated using the succession of surface vegetation along the chronosequence, the combined changes of vegetation and soil chemistry, and finally vegetation and seed bank composition. 4The sampled calcareous grasslands were less resilient following disturbance than the mesotrophic grasslands, with slower colonization of bare ground and target species re-assembly. The mesotrophic grasslands typically took between 30 and 40 years to re-establish following disturbance, whereas calcareous grasslands took at least 50 years. 5Even after such long time periods, there remained subtle but significant differences between the vegetation composition of the disturbed and undisturbed swards. Perennial forb species, particularly hemicryptophytes, persisted at higher frequencies in swards disturbed 50 years ago than in undisturbed swards. 6Synthesis and applications. Prediction of habitat resilience following disturbance is dependent on which components of the system are investigated. However, data such as that presented here can help land managers understand how palimpsests of current habitat characteristics may have evolved, and how disturbance regimes may be managed in the future. It is likely that the resilience of grasslands such as those on SPTA may have been overestimated, and perceptions of habitat carrying capacity for disturbance events may require re-evaluation. [source] The relationship between soil seed bank, above-ground vegetation and disturbance intensity on old-field successional permanent plotsAPPLIED VEGETATION SCIENCE, Issue 4 2009Michaela Dölle Abstract Questions: How does disturbance and successional age influence richness, size and composition of the soil seed bank? What is the potential contribution of the soil seed bank to the plant community composition on sites differing in their successional age or disturbance intensity? Location: Experimental Botanical Garden of Göttingen University, central Germany. Methods: Above-ground vegetation and soil seed bank were studied on formerly arable fields in a 36-year-old permanent plot study with five disturbance intensities, ranging from yearly ploughing via mowing to long-term uninterrupted succession. We compared species compositions, seed densities and functional features of the seed bank and above-ground vegetation by using several methods in parallel. Results: The seed bank was mainly composed of early successional species typical of strongly disturbed habitats. The difference between seed bank composition and above-ground vegetation decreased with increasing disturbance intensity. The species of greatest quantitative importance in the seed bank was the non-native forb Solidago canadensis. Conclusions: The ability of a plant community to regenerate from the soil seed bank dramatically decreases with increasing time since abandonment (successional age) and with decreasing disturbance intensity. The present study underlines that plant species typical of grasslands and woodlands are limited by dispersal capacity, owing to low capacity for accumulation of seeds in the soil and the fact that most species do not build up persistent seed banks. Rare and target species were almost absent from the seed bank and will, after local elimination, depend on reintroduction for continuation of their presence. [source] The Importance of Where to Dump the Refuse: Seed Banks and Fine Roots in Nests of the Leaf-Cutting Ants Atta cephalotes and A. colombica,BIOTROPICA, Issue 1 2000Alejandro G. Farji-Brener ABSTRACT The location of the nutrient-rich organic refuse produced by a leaf-cutting ant colony varies among ant species. Atta cephalotes locate their organic refuse in subterranean chambers, whereas A. colombica place their organic refuse on the soil surface near the nest. We studied the effect of the absence or presence of external organic refuse on the abundance of fine roots and seed bank composition in the superficial horizons of ant nests. We sampled soils from ant nests or dumps and adjacent areas of 15 adult nests of A. cephalotes at La Selva (LS), Costa Rica, and of 15 of A. colombica nests on Barro Colorado Island (BCI), Panama. Soils from A. cephalotes nests did not differ from adjacent soils in abundance of fine-root and seed diversity. In contrast, organic refuse from A. colombica nests was less diverse in seed composition (due to the great abundance of Miconia argentea) and had a greater abundance of fine roots than adjacent areas. Thus the external location of the ant-nest organic refuse is potentially important in determining the different types of plant recolonization in abandoned or dead ant nests. The relative abundance of these Atta species may influence the structure and/or composition of tropical forests. RESUMEN En las hormigas cortadoras de hojas, la ubicación de los desechos orgánicos ricos en nutrientes producidos por el hongo que cultivan varía segun la especie. Mientras Atta cephalotesubica sus desechos orgánicos en cámaras subterráncas, A. colombicalos coloca sobre la superficie del suelo cerca del nido. Nosotros estudiamos el efecto de la presencia o ausencia de desechos orgánicos externos sobre la abundancia de raíces finas y la composición del banco de semillas en los suelos superficiales cerca de los hormigueros. Para ello sacamos muestras de basureros o suelo superficial en 15 nidos y areas adjacentes de A. cephalotesen La Selva (LS), Costa Rica, y en 15 nidos de A. colombica ubicados en Barro Colorado (BCI), Panamá. Los suelos de A. cephalotesno difirieron de los suelos adjacentes en abundancia de raíces finas ni en la diversidad de semillas. Por el contrario, los desechos orgánicos externos en nidos de A. colombicafueron menos diversos en composición de semillas (debido principalmente a la gran dominancia de Miconia argentea) y tuvieron una mayor concentración de raices finas que los suelos adyacentes. La ubicación de los desechos es poten-cialmente importance en determinar los diferentes tipos de plantas que pueden recolonizar los nidos abandonados o muertos. Por lo tanto, la abundancia relativa de estas especies de Atta pueden influir en la estructura y/composicion de los bosques tropicales. [source] |