|Forest Investment Account (FIA) - Forest Science Program|
|FIA Project Y081045|
|Development of cost-effective health indicators for fescue grasslands of British Columbia|
|Project lead: Newman, Reg (BC Ministry of Forests and Range)|
|Contributing Authors: Lamagna, Sarah; Krzic, Maja; Newman, Reg F.|
|Subject: Forest Investment Account (FIA), British Columbia|
|Series: Forest Investment Account (FIA) - Forest Science Program|
|Understanding the effects that cattle have on vegetation, soil, and hydrologic parameters is the first step in developing sensitive and unambiguous indicators of rangeland health. Cattle may affect the environment directly by trampling, grazing/browsing, and manure deposition but may also have indirect affects through interactions among altered plant species composition, altered hydrology, altered energy flows, and altered nutrient cycling. These effects are cumulative, in some cases the result of 150 years of grazing activity. |
The need for sustainability criteria and indicators was identified at the Earth Summit in Rio di Janeiro (1992), and subsequently in Montreal (2000) and Johannesburg (2002), but little progress has been made in developing soil and plant indicators for temperate forest and rangeland ecosystems. Studies on development and application of criteria and indicators for forests and rangelands are often lacking, or have been done on a limited number of sites with relatively narrow climatic and soil ranges (Working Group on Criteria and Indicators for Conservation and Sustainable Management of Temperate and Boreal Forests 1999; Page-Dumroese et al. 2000). Identifying vegetation and soil properties that integrate important ecological processes would provide a key link between higher-level theory and operational evaluations at small scales where most rangeland management practices occur. It is broadly recognized that basic research is required in the definition of soil and vegetation indicators that reflect important plant-soil functional processes. These soil and vegetation indicators must show relationships with rangeland ecosystem-level responses (e.g., productivity, nutrient cycling) to disturbances and management (e.g., rodents, grazing). The properties must be easily monitored and audited, and also be relevant to evaluation of basic rangeland practices.
The proposed study will determine effects of long-term cattle grazing on soil properties and vegetative characteristics of rough fescue (Festuca campestris Rydb.) grasslands within the Interior Douglas-fir zone in southern interior British Columbia (BC). The study will be replicated at 10 sites in the Thompson-Nicola region. Each site will have a long-term exclosure and an adjacent grazed area. Exclosures maintained by the Range Reference Areas (RRA) program will be used wherever possible. Soil and vegetation sampling will be conducted at randomly determined locations along five 30-m long transects both inside and outside of the exclosures during May – August 2007. Three principal criteria for determination of rangeland health were outlined by Busby (1994) and they include: 1) degree of soil stability and watershed function, 2) integrity of nutrient cycles and energy flows, and 3) presence of functioning recovery mechanisms. To address these criteria we are planning to determine the following parameters in grazed and adjacent ungrazed areas: 1. Degree of soil stability and watershed function a) soil bulk density and mechanical resistance, indicators of soil compaction, hydrologic function, and soil pore stability b) soil aggregate stability, describes the resistance of soil structure to external disturbance 2. Integrity of nutrient cycles and energy flows a) total soil carbon and nitrogen, representing total inventory of soil organic matter b) soil polysaccharides, indicator of the most readily available source of energy for soil microorganisms c) living above-ground biomass, an estimate of site productivity (energy capture) d) dead above-ground biomass, an indicator of nutrient cycling 3. Presence of functioning recovery mechanisms a) flowering culm density of key late seral grasses, an indication of reproductive capacity - to determine plant recruitment potential The properties listed above are selected because they can be obtained using sound, cost-effective monitoring techniques and they assess key processes known to be affected by grazing. The proposed study supports FSP SPAC Research Strategy (2006-2016) theme 3.0 Indicators, thresholds, and monitoring systems to improve stewardship of BC’s rangeland resources through development of knowledge for sustainable management. Information from this study will assist with the development of ecosystem knowledge to manage upland rangelands (topic 3.1. Development of indicators and monitoring systems). The proposed project will address some aspects of “the development of indicators and monitoring systems”. Specifically, the project will develop knowledge on variables that are the most “sensitive to the state of the system and provide unambiguous information about the system's response to (rangeland) management". The proposed study is collaborative with an ongoing FSP project (Y071154) “Linking range health assessment methodology with science”. The linkage of the two projects will result in many two-way benefits. The proposed study will utilize some of the data already collected in 2006 under project Y071154 to examine how long-term cattle grazing has altered key ecological processes in the rough fescue grasslands. In addition to meeting that fundamental objective, the results of the proposed study will provide feedback to one of the objectives of Y071154. The focus of project Y071154 was to determine the reliability of two Range Health assessment methodologies (one current, one proposed). Vegetation and soil parameters that are known to vary in response to annual weather patterns (e.g., above-ground biomass, seed-head count for key bunchgrass, soil mechanical resistance) will be sampled for a second year during the proposed study, expanding the data base established during the Y071154 project. Finally, the proposed study will provide further guidance on the questions that should be asked when determining the “health” of grassland systems (e.g., information on the most sensitive parameters, information on parameters that may predict that an ecological threshold is about to be crossed).
Executive summary (15Kb)
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Updated August 16, 2010
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