Barred owls recently expanded their range and now completely overlap that of the northern spotted owl. Current declines in northern spotted owl populations are largely attributable to this sympatry with barred owls. Lethal removal of barred owls is being considered and tested as a method of managing the negative impacts on spotted owls. The size and distribution of removal areas may influence the efficacy and efficiency with which an area can be maintained free of barred owls. I created an individual-based spatially-explicit population model to compare alternative spatial strategies for removing barred owls in a localized area. Large, continuous removal areas maintain lower barred owl occupancy and require fewer owls to be removed than smaller fragmented removal areas for a given level of removal effort. The model is most sensitive to adult and subadult survival as well as reproduction and the range over which an owl can detect a potential mate, of which the latter two parameters do not have empirical field estimates. This model could be adapted to answer further questions regarding barred owl removal and also incorporate geographic information system data to evaluate removal strategies on real-world properties.

Conclusions, and Recommendations P.75

Invasive species are everywhere, from forests and prairies to mountaintops and river mouths. Their rampant nature and sheer numbers appear to overtake fragile native species and forever change the ecosystems that they depend on. Concerns that invasive species represent significant threats to global biodiversity and ecological integrity permeate conversations from schoolrooms to board rooms, and concerned citizens grapple with how to rapidly and efficiently manage their populations. These worries have culminated in an ongoing “war on invasive species,” where the arsenal is stocked with bulldozers, chainsaws, and herbicides put to the task of their immediate eradication. In Hawaii, mangrove trees (Avicennia spp.) are sprayed with glyphosate and left to decompose on the sandy shorelines where they grow, and in Washington, helicopters apply the herbicide Imazapyr to smooth cordgrass (Spartina alterniflora) growing in estuaries. The “war on invasive species” is in full swing, but given the scope of such potentially dangerous and ecologically degrading eradication practices, it is necessary to question the very nature of the battle. Beyond the War on Invasive Species offers a much-needed alternative perspective on invasive species and the best practices for their management based on a holistic, permaculture-inspired framework. Utilizing the latest research and thinking on the changing nature of ecological systems, Beyond the War on Invasive Species closely examines the factors that are largely missing from the common conceptions of invasive species, including how the colliding effects of climate change, habitat destruction, and changes in land use and management contribute to their proliferation. There is more to the story of invasive species than is commonly conceived, and Beyond the War on Invasive Species offers ways of understanding their presence and ecosystem effects in order to make more ecologically responsible choices in land restoration and biodiversity conservation that address the root of the invasion phenomenon. The choices we make on a daily basis—the ways we procure food, shelter, water, medicine, and transportation—are the major drivers of contemporary changes in ecosystem structure and function; therefore, deep and long-lasting ecological restoration outcomes will come not just from eliminating invasive species, but through conscientious redesign of these production systems.

Winner of the 2022 Rachel Carson Environment Book Award * Winner of the 2022 Science in Society Journalism Award (Books) * Finalist for the Los Angeles Times Book Prize “Thoughtful, insightful, and wise, Wild Souls is a landmark work.”--Ed Yong, author of An Immense World "Fascinating . . . hands-on philosophy, put to test in the real world . . . Marris believes that our idea of wildness--our obsession with purity--is misguided. No animal remains untouched by human hands . . . the science isn't the hard part. The real challenge is the ethics, the act of imagining our appropriate place in that world." --Outside Magazine From an acclaimed environmental writer, a groundbreaking and provocative new vision for our relationships with--and responsibilities toward--the planet's wild animals. Protecting wild animals and preserving the environment are two ideals so seemingly compatible as to be almost inseparable. But in fact, between animal welfare and conservation science there exists a space of underexamined and unresolved tension: wildness itself. When is it right to capture or feed wild animals for the good of their species? How do we balance the rights of introduced species with those already established within an ecosystem? Can hunting be ecological? Are any animals truly wild on a planet that humans have so thoroughly changed? No clear guidelines yet exist to help us resolve such questions. Transporting readers into the field with scientists tackling these profound challenges, Emma Marris tells the affecting and inspiring stories of animals around the globe--from Peruvian monkeys to Australian bilbies, rare Hawai'ian birds to majestic Oregon wolves. And she offers a companionable tour of the philosophical ideas that may steer our search for sustainability and justice in the non-human world. Revealing just how intertwined animal life and human life really are, Wild Souls will change the way we think about nature-and our place within it.

Why our cats are a danger to species diversity and human health In 1894, a lighthouse keeper named David Lyall arrived on Stephens Island off New Zealand with a cat named Tibbles. In just over a year, the Stephens Island Wren, a rare bird endemic to the island, was rendered extinct. Mounting scientific evidence confirms what many conservationists have suspected for some time—that in the United States alone, free-ranging cats are killing birds and other animals by the billions. Equally alarming are the little-known but potentially devastating public health consequences of rabies and parasitic Toxoplasma passing from cats to humans at rising rates. Cat Wars tells the story of the threats free-ranging cats pose to biodiversity and public health throughout the world, and sheds new light on the controversies surrounding the management of the explosion of these cat populations. This compelling book traces the historical and cultural ties between humans and cats from early domestication to the current boom in pet ownership, along the way accessibly explaining the science of extinction, population modeling, and feline diseases. It charts the developments that have led to our present impasse—from Stan Temple's breakthrough studies on cat predation in Wisconsin to cat-eradication programs underway in Australia today. It describes how a small but vocal minority of cat advocates has campaigned successfully for no action in much the same way that special interest groups have stymied attempts to curtail smoking and climate change. Cat Wars paints a revealing picture of a complex global problem—and proposes solutions that foresee a time when wildlife and humans are no longer vulnerable to the impacts of free-ranging cats.

This set of exercises has been created expressly for students and teachers of conservation biology and wildlife management who want to have an impact beyond the classroom. The book presents a set of 32 exercises that are primarily new and greatly revised versions from the book's successful first edition. These exercises span a wide range of conservation issues: genetic analysis, population biology and management, taxonomy, ecosystem management, land use planning, the public policy process and more. All exercises discuss how to take what has been learned and apply it to practical, real-world issues. Accompanied by a detailed instructor’s manual and a student website with software and support materials, the book is ideal for use in the field, lab, or classroom. Also available: Fundamentals of Conservation Biology, 3rd edition (2007) by Malcolm L Hunter Jr and James Gibbs, ISBN 9781405135450 Saving the Earth as a Career: Advice on Becoming a Conservation Professional (2007) by Malcolm L Hunter Jr, David B Lindenmayer and Aram JK Calhoun, ISBN 9781405167611