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Phosphorus pollution severely impairs the water quality of rivers in Australia and worldwide. Conceptual models have proved useful to assess management impact on phosphorus loads, particularly in data-sparse environments. This paper develops and evaluates the coupling of a point-scale model (HowLeaky2008) to a catchment scale model (CatchMODS) to enhance modelling of farm management impacts on in-stream phosphorus loads. The model was tested in two adjacent catchments in northern Victoria (Avon-Richardson and Avoca), Australia. After calibration of the in-stream attenuation parameter against measurements at gauging stations, the model simulated specific annual phosphorus loads across the catchments well (Nash–Sutcliffe model efficiency of 0.52 in the Avon-Richardson and 0.83 for the Avoca catchment). Phosphorus loads at both catchment outlets under current conditions were estimated at 7 t y−1 and were dominated by field exports. Changes to farm management practices, i.e. the use of perennial pastures in grazing systems and zero-tillage in cropping systems were estimated to reduce phosphorus load by 31% in the Avon-Richardson catchment and 19% in the Avoca catchment, relative to current practices (annual pasture and minimum tillage). The model afforded a major improvement in conceptual modelling by explicit simulation of the impacts of soil and climatic conditions on field-scale exports and by placing them in the context of landscape processes. [Copyright &y& Elsevier]

Despite growing interest in promoting urban biodiversity conservation, there are few concrete examples of how nature stewardship initiatives can be rapidly scaled, in number and across landscapes. This paper explores the factors that promote or inhibit the proliferation and impact of collaborations between citizens and their local governments that involve residents in municipal biodiversity conservation efforts in their gardens (wildlife gardening). We studied the Gardens for Wildlife Victoria network in Australia, which supports citizen-agency co-development of municipal wildlife gardening programs. In three years the network has expanded from one program to 39 initiatives in various developmental stages in 49% of the local government areas in the state of Victoria. Data are drawn from 21 semi-structured interviews of network participants running or developing programs in 12 municipalities, complemented by a survey of 33 network participants, and participants' evaluation of network workshops. We find that scaling occurs in four different domains of policy, values, locales and participants. Scaling is influenced by six interlinked factors: empowerment of actors; a civil-agency co-design and delivery model; conservation framing; links to and between landscapes and communities; resources – particularly time; and the network's role in promoting innovation and shared learning. Key barriers include short-term, top-down, and monetary agency foci; conservation framed as the principal domain of specialists and professionals; and prioritisation of listed species rather than local species more broadly. We present a framework for considering scaling of biodiversity stewardship and related factors. • Case study shows how biodiversity stewardship collaborations multiply among cities. • Programs are designed to link public and private land stewardship. • Stewardship programs, locales, policies, and values are spread. • Leaders are empowered by belief in impact, meaning, competence, choice. • Enablers are a network, citizen-agency codesign, inclusivity, place-based links. [ABSTRACT FROM AUTHOR]