Defining the Impact of Non‐Native Species

Non‐native species cause changes in the ecosystems to which they are introduced. These changes, or some of them, are usually termed impacts; they can be manifold and potentially damaging to ecosystems and biodiversity. However, the impacts of most non‐native species are poorly understood, and a synthesis of available information is being hindered because authors often do not clearly define impact. We argue that explicitly defining the impact of non‐native species will promote progress toward a better understanding of the implications of changes to biodiversity and ecosystems caused by non‐native species; help disentangle which aspects of scientific debates about non‐native species are due to disparate definitions and which represent true scientific discord; and improve communication between scientists from different research disciplines and between scientists, managers, and policy makers. For these reasons and based on examples from the literature, we devised seven key questions that fall into 4 categories: directionality, classification and measurement, ecological or socio‐economic changes, and scale. These questions should help in formulating clear and practical definitions of impact to suit specific scientific, stakeholder, or legislative contexts. Definiendo el Impacto de las Especies No‐Nativas     

Modeling sediment and nitrogen export from a rural watershed in eastern Canada using the soil and water assessment tool

Watershed simulation models can be used to assess agricultural nonpoint-source pollution and for environmental planning and improvement projects. However, before application of any process-based watershed model, the model performance and reliability must be tested with measured data. The Soil and Water Assessment Tool version 2005 (SWAT2005) was used to model sediment and nitrogen loads from the Thomas Brook Watershed, which drains a 7.84 km rural landscape in the Annapolis Valley of Nova Scotia, Canada. The Thomas Brook SWAT model was comprised of 28 subbasins and 265 hydrologic response units, most of them containing agricultural land use, which is the main nonpoint nitrogen source in the watershed. Crop rotation schedules were incorporated into the model using field data collected within Agriculture and Agri-Food Canada's Watershed Evaluation of Beneficial Management Practices program. Model calibration (2004-2006) and validation (2007-2008) were performed on a monthly basis using continuous stream flow, sediment, and nitrogen export measurements. Model performance was evaluated using the coefficient of determination, Nash-Sutcliff efficiency (NSE), and percent bias (PBIAS) statistics. Study results show that the model performance was satisfactory (NSE > 0.4; > 0.5) for stream flow, sediment, nitrate-nitrogen, and total nitrogen simulations. Annual corn, barley, and wheat yields were also simulated well, with PBIAS values ranging from 0.3 to 7.2%. This evaluation of SWAT demonstrated that the model has the potential to be used as a decision support tool for agricultural watershed management in Nova Scotia.     

Protected‐Area Boundaries as Filters of Plant Invasions

Abstract: Human land uses surrounding protected areas provide propagules for colonization of these areas by non‐native species, and corridors between protected‐area networks and drainage systems of rivers provide pathways for long‐distance dispersal of non‐native species. Nevertheless, the influence of protected‐area boundaries on colonization of protected areas by invasive non‐native species is unknown. We drew on a spatially explicit data set of more than 27,000 non‐native plant presence records for South Africa's Kruger National Park to examine the role of boundaries in preventing colonization of protected areas by non‐native species. The number of records of non‐native invasive plants declined rapidly beyond 1500 m inside the park; thus, we believe that the park boundary limited the spread of non‐native plants. The number of non‐native invasive plants inside the park was a function of the amount of water runoff, density of major roads, and the presence of natural vegetation outside the park. Of the types of human‐induced disturbance, only the density of major roads outside the protected area significantly increased the number of non‐native plant records. Our findings suggest that the probability of incursion of invasive plants into protected areas can be quantified reliably.     

Risk of Public Disclosure in Environmental Farm Plan Programs: Characteristics and Mitigating Legal and Policy Strategies

Although various studies have shown thatfarmers believe there is the need for a producer-ledinitiative to address the environmental problems fromagriculture, farmers in several Canadian provinceshave been reluctant to widely participate inEnvironmental Farm Plan (EFP) programs. Few studieshave examined the key issues associated with adoptingEFP programs based on farmers', as opposed to policymakers', perspectives on why producers are reluctantto participate in the program. A study adapting VanRaaij's (1981) conceptual model of the decision-makingenvironment of the firm, and prospect theory on valuefunctions associated with the gains and losses fromrisky choices can be used to characterize how farmersperceive potential risks in environmental farmplanning. This framework can be used to assert thatfarmers are concerned about risks of public disclosureof potentially incriminating environmental informationfrom farms because the EFP program requirements foridentification and extensive documentation of farminformation is perceived by farmers as facilitatingthe accessibility of environmental information to thepublic, and public investigative efforts. Although theEFP program does not explicitly generate informationabout the environmental conditions of a farm nor thedisclosure of such information to the public, itcreates the possibility of generating and divulgingpotentially incriminating information that the farmermay want to treat as confidential. Yet, alone, theserisks of public disclosure concerns should not preventfarmers from participating in the EFP. Awareness ofand participation in environmental farm planning canbe increased if farmers and policy makers understandwhat the risks are, and how they arise. Aspects of theEFP process that have the potential to generate riskof public disclosure concerns relate to farm reviews,documentation and record keeping, and correctiveaction plans. There are legal and policy instrumentsthat can offer various forms of protection and helpminimize such risks, and these need to be assessed.     

Effect of Nutrient Management Planning on Crop Yield, Nitrate Leaching and Sediment Loading in Thomas Brook Watershed

Government priorities on provincial Nutrient Management Planning (NMP) programs include improving the program effectiveness for environmental quality protection, and promoting more widespread adoption. Understanding the effect of NMP on both crop yield and key water-quality parameters in agricultural watersheds requires a comprehensive evaluation that takes into consideration important NMP attributes and location-specific farming conditions. This study applied the Soil and Water Assessment Tool (SWAT) to investigate the effects of crop and rotation sequence, tillage type, and nutrient N application rate on crop yield and the associated groundwater ${\text{NO}_{3}}^{ - } {\text{-N }}$ leaching and sediment loss. The SWAT model was applied to the Thomas Brook Watershed, located in the most intensively managed agricultural region of Nova Scotia, Canada. Cropping systems evaluated included seven fertilizer application rates and two tillage systems (i.e., conventional tillage and no-till). The analysis reflected cropping systems commonly managed by farmers in the Annapolis Valley region, including grain corn-based and potato-based cropping systems, and a vegetable-horticulture system. ANOVA models were developed and used to assess the effects of crop management choices on crop yield and two water-quality parameters (i.e., ${\text{NO}_{3}}^{ - } {\text{-N }}$ leaching and sediment loading). Results suggest that existing recommended N-fertilizer rate can be reduced by 10–25 %, for grain crop production, to significantly lower ${\text{NO}_{3}}^{ - } {\text{-N }}$ leaching (P > 0.05) while optimizing the crop yield. The analysis identified the nutrient N rates in combination with specific crops and rotation systems that can be used to manage ${\text{NO}_{3}}^{ - } {\text{-N }}$ leaching while balancing impacts on crop yields within the watershed.     

What motivates farmers to participate in the Nova Scotia environmental farm plan program? Evidence and environmental policy implications

Program stakeholders are interested in better understanding farmers' experience, and factors that affect farmer participation in the relatively new Environmental Farm Plan (EFP) program, implemented in several provinces in Canada. To increase relevance of the research findings to EFP program administrators and policy makers, the research methods emphasised determining whether relationships exist among program-related variables, and how such relationships affect farmers' decision choices and behaviour. Traditional farmer and farm attributes that have contrasting effects in agricultural innovation adoption and conservation management (namely age, and formal education completed), were not associated with EFP program participation. Farm income, years of farming experience, and type of agribusiness managed were associated with participation in the Nova Scotia EFP program. Although program participants tended to have higher incomes, overall, non-financial considerations dominated monetary considerations in Nova Scotia farmers' reasons for participating in the Nova Scotia EFP. Helping to publicize positive farm stewardship practices was reported as the most important reason for participating in the EFP scheme, followed by its use to help improve relationships with non-farming neighbours, and to comply with government environmental regulations. In contrast, and somewhat a surprising finding, minimizing potential farm environmental risk, program administrators' raison d'être for promoting the NS EFP, was ranked the lowest, with no respondent rating that as a "very important" or "extremely important" reason for participating in the EFP program.     

Risk of public disclosure in environmental farm plan programs: Characteristics and mitigating legal and policy strategies

Although various studies have shown that farmers believe there is the need for a producer-led initiative to address the environmental problems from agriculture, farmers in several Canadian provinces have been reluctant to widely participate in Environmental Farm Plan (EFP) programs. Few studies have examined the key issues associated with adopting EFP programs based on farmers’, as opposed to policy makers’, perspectives on why producers are reluctant to participate in the program. A study adapting Van Raaij’s (1981) conceptual model of the decision-making environment of the firm, and prospect theory on value functions associated with the gains and losses from risky choices can be used to characterize how farmers perceive potential risks in environmental farm planning. This framework can be used to assert that farmers are concerned about risks of public disclosure of potentially incriminating environmental information from farms because the EFP program requirements for identification and extensive documentation of farm information is perceived by farmers as facilitating the accessibility of environmental information to the public, and public investigative efforts. Although the EFP program does not explicitly generate information about the environmental conditions of a farm nor the disclosure of such information to the public, it creates the possibility of generating and divulging potentially incriminating information that the farmer may want to treat as confidential. Yet, alone, these risks of public disclosure concerns should not prevent farmers from participating in the EFP. Awareness of and participation in environmental farm planning can be increased if farmers and policy makers understand what the risks are, and how they arise. Aspects of the EFP process that have the potential to generate risk of public disclosure concerns relate to farm reviews, documentation and record keeping, and corrective action plans. There are legal and policy instruments that can offer various forms of protection and help minimize such risks, and these need to be assessed.