Urban open spaces from a dispersal perspective: lessons from an individual-based model approach to assess the effects of landscape patterns on the viability of wildlife populations

Green areas drawn on a city plan represent open spaces that have different meanings for humans and wildlife. Diverse kinds of green may influence species viability in urban environments. It is necessary to understand what those areas mean for wildlife populations and how land-use changes affect habitats and movements for making scientifically defensible planning and design decisions. My objective was to demonstrate how open space and urban development patterns affect the viability of wildlife populations in urbanizing landscapes from a movements perspective. Eight scenarios for 2060 for an urbanizing area near Portland, Oregon combined four open space (none, corridors, parks, and network) with two urban development patterns (compact and dispersed). Dispersal model HexSim simulated three target species – Red-legged frog (Rana aurora aurora), Western meadowlark (Sturnella neclecta) and Douglas squirrel (Tamasciurus douglasii) – movements on those scenarios to compare and contrast sustained populations to the ca. 2010 baseline landscape. Network scenarios presented the largest number of frog breeders. Greenway scenarios showed the largest populations of squirrels. Park and network scenarios sustained viable populations of meadowlarks, but park scenarios performed best. Compact development scenarios performed best for most indicators, while dispersed development scenarios performed better for meadowlarks. Network scenarios performed best when considering the collective of species. Networks presented more diverse habitats, sustaining higher diversity of species. For plans to sustain more species, more comprehensive and diverse habitats must be promoted, otherwise trade-offs should be expected – like the extinction of meadowlarks in greenway scenarios.

International consensus principles for ethical wildlife control

Human-wildlife conflicts are commonly addressed by excluding, relocating, or lethally controlling animals with the goal of preserving public health and safety, protecting property, or conserving other valued wildlife. However, declining wildlife populations, a lack of efficacy of control methods in achieving desired outcomes, and changes in how people value animals have triggered widespread acknowledgment of the need for ethical and evidence-based approaches to managing such conflicts. We explored international perspectives on and experiences with human-wildlife conflicts to develop principles for ethical wildlife control. A diverse panel of 20 experts convened at a 2-day workshop and developed the principles through a facilitated engagement process and discussion. They determined that efforts to control wildlife should begin wherever possible by altering the human practices that cause human-wildlife conflict and by developing a culture of coexistence; be justified by evidence that significant harms are being caused to people, property, livelihoods, ecosystems, and/or other animals; have measurable outcome-based objectives that are clear, achievable, monitored, and adaptive; predictably minimize animal welfare harms to the fewest number of animals; be informed by community values as well as scientific, technical, and practical information; be integrated into plans for systematic long-term management; and be based on the specifics of the situation rather than negative labels (pest, overabundant) applied to the target species. We recommend that these principles guide development of international, national, and local standards and control decisions and implementation.