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Restoration Potential (restoration + potential)
Selected AbstractsRestoration potential of Brigalow regrowth: Insights from a cross-sectional study in southern QueenslandECOLOGICAL MANAGEMENT & RESTORATION, Issue 3 2007Timothy S. Chandler First page of article [source] Determining the important environmental variables controlling plant species community composition in mesotrophic grasslands in Great BritainAPPLIED VEGETATION SCIENCE, Issue 4 2009Veronika Kalusová Abstract Question: What is the relative importance of local site effects and selected important environmental variables in determining plant species composition? How do species respond to these environmental variables? Location: Ten mesotrophic grassland sites of high conservation value in southern England. Methods: Species cover was assessed in between 10 and 25 randomly selected 1-m2 quadrats at each site. At each quadrat degree of waterlogging (W), soil Olsen extractable phosphorus (P) and soil pH were measured. Variation partitioning was used to separate site and soil effects, and HOF (Huisman, Olff & Fresco) modelling was used to produce response curves for the major species on soil gradients, based on coenoclines derived from partial canonical correspondence analysis (pCCA). Results: Variation partitioning identified Site as the most important environmental variable (34.6%). Only 18.7% was accounted for by the three soil variables together; W (degree of waterlogging), P and pH accounted for 11.1%, 5.7% and 4.3%, respectively in raw form with 2.4% shared. However, when Site and the other soil variables were removed the variation explained reduced to 2.3% for W, 1.1% for P and 1.0% for pH. The species responses to each of these soil environmental factors could be separated into four types on each gradient. Most species were abundant at low W, low soil P and intermediate pH. Conclusions: Site-based factors were more important than the three soil variables, which were assumed to be directly or indirectly associated with productivity. This implies that each site has unique properties that are more important than the soil variables. The three soil factors were, however, significant and the groups of the most common species, based on significant response curves, can be used as a first approximation of indicators of environmental conditions in British mesotrophic grasslands for conservation. However, W accounted for most variation, and the current reliance on soil available P and soil pH for assessing conservation/restoration potential should be viewed with caution. [source] Exotic Grass Invasions: Applying a Conceptual Framework to the Dynamics of Degradation and Restoration in Australia's Tropical SavannasRESTORATION ECOLOGY, Issue 2 2010Kristine J. Brooks Plant invasions can cause severe degradation of natural areas. The ability of an ecosystem to recover autogenically from degradation following weed control is in part determined by the type and magnitude of changes to both biotic and abiotic processes caused by the invasion and how these interact with structural and functional components of the ecosystem. Recently, a number of conceptual frameworks have been proposed to describe the dynamics of degradation and regeneration in degraded ecosystems. We assessed the utility of one of these frameworks in describing the degradation and restoration potential of Australia's tropical savannas following exotic grass invasion. First, we identified easily measured structural characteristics of putative states. We found that a continuous cover of the exotic grasses Gamba grass (Andropogon gayanus Kunth.) and Perennial mission grass (Pennisetum polystachion (L.) Schult.) under an intact tree canopy was a common state with an understorey characterized by reduced species richness and abundance and a change in the relative contribution of functional groups. Further degradation led to a state where the canopy was severely reduced and the impacts on the understorey were more severe. In both states, the seed bank was substantially less degraded than the understorey vegetation. Guided by the framework, we combined our study with other studies to construct a conceptual model for degradation in exotic grass-invaded savannas. [source] Buffering an Acidic Stream in New Hampshire with a Silicate MineralRESTORATION ECOLOGY, Issue 3 2004Gene E. Likens Abstract Ground and pelletized Wollastonite (Wo; CaSiO3) was added to a 50-m reach of an anthropogenically acidified stream within the Hubbard Brook Experimental Forest, New Hampshire, to evaluate its buffering and restoration potential. The Wo was highly effective in raising the pH, acid-neutralizing capacity (ANC), dissolved inorganic carbon (DIC), and Ca2+ concentrations of the stream water, but during the short duration of the experiment had no discernable effect on the stream biota. After initial, spike-like fluctuations in pH and concentrations of ANC, DIC, and Ca2+, the relatively slow dissolution rates of the Wo dampened extreme concentrations and contributed to relatively long-lasting (4 months) amelioration of streamwater acidity. Changes in concentrations of Ca2+, dissolved Si, ANC, and DIC were inversely related to streamflow. After several high, stream-discharge events, concentrations quickly and consistently returned to pre-event conditions. [source] Depth distribution and composition of seed-banks in alien-invaded and uninvaded fynbos vegetationAUSTRAL ECOLOGY, Issue 1 2002Patricia M. Holmes Abstract South African fynbos vegetation is threatened on a large scale by invasive woody plants. A major task facing nature conservation managers is to restore invaded areas. The aim of this study was to determine the restoration potential of fynbos following dense invasion by the Australian tree Acacia saligna. The impacts of dense invasion on seed-bank composition and depth distribution were investigated to determine which fynbos guilds and species have the most persistent seed-banks. Soil samples were excavated at three different depths for invaded and uninvaded vegetation at two sand plain and mountain fynbos sites. Seed-banks were determined using the seedling emergence approach. Invasion caused a significant reduction in seed-bank density and richness at all sites. There was a significant, but smaller, reduction in seed-bank density and richness with soil depth at three sites. Seed-bank composition and guild structure changed following invasion. Low persistence of long-lived obligate seeders in sand plain fynbos seed-banks indicates that this vegetation type will be difficult to restore from the seed-bank alone following alien clearance. The dominance of short-lived species, especially graminoids, forbs and ephemeral geophytes, suggests that regenerating vegetation will develop into a herbland rather than a shrubland. It is recommended that seed collecting and sowing form part of the restoration plan for densely invaded sand plain sites. As seed density remained higher towards the soil surface following invasion, there is no general advantage in applying a mechanical soil disturbance treatment. However, if the shallow soil seed-bank becomes depleted, for example following a hot fire through dense alien slash, a soil disturbance treatment should be given to exhume the deeper viable seed-bank and promote recruitment. [source] | ||||||||||