LECTURE18 Human Disruption and Ecological Restoration Why can,'t we just let nature take its course? The model is based on rigorous science and incorporates some of the longest-running ecosystem monitor ing data, inventory, and n ecologically based treatment is site specific. Principles and framework Scientific framework. Social and political framework; Ecosystem Management framework, Economic framework, Ethical framework; Temporal framework Principles and framework Scientific framework. Restoration treatments are constantly adapted to reflect new scientific understanding Social and political framework Ecological restoration recognizes the important role people play in the landscape Principles and framework Operational framew This defines where treatments are applied on the grounds Ecosystem management framework integrated with overall ecosystem conservation and management goals Principles and framework balance between short term(1-10yr)and long term perspectives is essential Tai Tong: Success or failure Tai Tong East Borrow Area is located in the northwestern New Territories. The site comprises of dissected ridges rad iating from it to the Yuen Long Plain. Besides the deeply incised valleys, which run parallel in a northwesterly direction, gullies are also abundant The vegetation was dominated by the secondary growth of Pinus massoniana, a large proportion of which had been killed by the nematode disease Excavation began in the early 1990s, and the site is excavated to an average depth of 8 metres Tai Tong: Success or failu This human action resulted in complete removal of the vegetation and topsoil, which is a typical example of soil destruction After excavation the soil is depleted in organic matter and nitrogen, and also acidic and infertile compared to the original soil. This poses great problem in ecological restoration of the site Tai Tong: Success or failure Nonetheless the exca ed to blend with the surrounding topography, covered with a 500-mm layer of in situ mater ials, with trees Tai Tong: Success or failure Hydroseeding technique was introduced to Hong Kong in the late 1970s. It is developed for the rapid establishment of grasses, and sometimes shrubs, slopes or disturbed areas The slurry contain ing a mixture of seeds, fertilizer, mulch fiber, soil solidifying agent and malachite green is spray ed onto the soil by use of a high-pressure jet Tai Tong: Success or failure Tai Tong: Success or failure he established grasses help to moderate microclimate cond itions and ameliorate soil. This will then pave the way for the planting of trees to enhance biodiversity and accelerate development. Six months after germination of the hydroseeded grasses, the slope is planted with trees to further stabilize the soil, accelerate forest development and enhance biodiversity Summary When damaged landscapes are restored, they of recovery known as“ succession” Understanding tics of wilderness help ecosystem restoration Early successional species are fast growin During succession, changes in species are due to facilitation, interference, life-history differences chronic patchinessLECTURE18 Human Disruption and Ecological Restoration 3 Why can't we just let nature take its course? The model is based on rigorous science and incorporates some of the longest-running ecosystem monitoring data, inventory, and research. An ecologically based treatment is site specific. Principles and framework Scientific framework; Social and political framework; Operational framework; Ecosystem Management framework; Economic framework; Ethical framework; Temporal framework. Principles and framework Scientific framework; Restoration treatments are constantly adapted to reflect new scientific understanding Social and political framework; Ecological restoration recognizes the important role people play in the landscape Principles and framework Operational framework; This defines where treatments are applied on the grounds Ecosystem management framework; integrated with overall ecosystem conservation and management goals Principles and framework Temporal framework; A balance between short term (1-10yr) and long term perspectives is essential Tai Tong: Success or failure Tai Tong East Borrow Area is located in the northwestern New Territories. The site comprises of dissected ridges radiating from it to the Yuen Long Plain. Besides the deeply incised valleys, which run parallel in a northwesterly direction, gullies are also abundant. Tai Tong: Success or failure The vegetation was dominated by the secondary growth of Pinus massoniana, a large proportion of which had been killed by the nematode disease Excavation began in the early 1990s; and the site is excavated to an average depth of 8 metres, Tai Tong: Success or failure This human action resulted in complete removal of the vegetation and topsoil, which is a typical example of soil destruction After excavation the soil is depleted in organic matter and nitrogen, and also acidic and infertile compared to the original soil. This poses great problem in ecological restoration of the site. Tai Tong: Success or failure Nonetheless, the excavated site was rehabilitated. The slopes were recontoured to blend with the surrounding topography, covered with a 500-mm layer of in situ materials, hydroseeded, and pit planted with trees. Tai Tong: Success or failure Hydroseeding technique was introduced to Hong Kong in the late 1970s. It is developed for the rapid establishment of grasses, and sometimes shrubs, slopes or disturbed areas. The slurry containing a mixture of seeds, fertilizer, mulch fiber, soil solidifying agent and malachite green is sprayed onto the soil by use of a high-pressure jet. Tai Tong: Success or failure Tai Tong: Success or failure The established grasses help to moderate microclimate conditions and ameliorate soil. This will then pave the way for the planting of trees to enhance biodiversity and accelerate development. Six months after germination of the hydroseeded grasses, the slope is planted with trees to further stabilize the soil, accelerate forest development and enhance biodiversity. Summary When damaged landscapes are restored, they undergo a process of recovery known as “succession” Understanding succession helps answer questions about characteristics of wilderness & help ecosystem restoration Summary Early successional species are fast growing During succession, changes in species are due to facilitation, interference, life-history differences & chronic patchiness