Browsing by Author "Pimm, Stuart L"

Nature is under immediate and increasing threat. Tales of destruction and deforestation abound despite the myriad interventions and investments by government bureaucracies, non-government organizations, and private land-owners. As the extinction crisis looms larger and demands on the public purse grow greater, understanding how science becomes policy and policy practice is more important than ever. As a result, and in response to the increasing insularity of conservation biology that has consciously nourished a careful separation of knowledge and action, of scientist and actor, I use this dissertation to navigate the nexus of conservation science, policy, and practice. I employ case studies in forest hydrology and species conservation, as well as cognitive theory, to examine how conservation science becomes policy. I collected field data from Lake Mead National Recreation Area and from the World Bank to explore how policies are translated into practice.

Current assumptions in conservation biology apportions these three separate but equal disciplines - science, policy, and practice - into one greater and two lesser, one that is pure and two that are sticky. But the transmission of knowledge from the Academy to the domains of conservation policy and practice, though difficult, is our mandate. As much as technical competence matters in conservation biology, so too does political literacy. After all, conservation occurs within a dynamic social, political, and institutional landscape. Nonetheless, the current emphasis in conservation biology is on answering questions in the natural sciences and, to a lesser degree, in economics. This focus is important, as is protecting scholarship from the daily pressures of a society that demands quick and ready answers. But scientific data is only one commodity among many that policy-makers and conservation practitioners trade in a tournament of values. Its usefulness lies in the wider social and political environment. Moreover, conservation biology is not simply an applied subset of biology or ecology. It is a mission-driven discipline that dedicates itself to the pursuit of science to save wildlife and wild lands. It encapsulates certain values as axioms. We hold these truths to be self-evident: that the diversity of life matters and that the struggle to end extinctions is meaningful.

Therefore, though conservation science, the design of conservation policies, and the practice of conservation are separate disciplines, they are closely related. For we must understand their different rules of evidence, speak their distinctive languages, and achieve credibility in all three disciplines while maintaining a sense of intellectual integrity in each. This requires respect for their differences as well as recognizing their shared mission in the service of wildlife and wild lands.

The Northern Andes stands as a bastion of unique and narrowly distributed global biodiversity. However, it has also experienced rapid transformation of habitats, posing a serious threat to species in the wild by shrinking their ranges. In this dissertation, I aim to deepen our comprehension of how species react to global changes, pinpointing areas where conservation efforts are lacking and highlighting urgent conservation priorities. Moreover, I demonstrate tangible conservation strategies designed to safeguard vulnerable species, while also prioritizing potential exploration regions to confirm the extent of their ranges.In the first chapter, I assess elevational retreats of nearly 200 range-restricted birds from their lower and upper elevational ranges (Medina et al. 2023). Using abundant crowd-sourced data from the Cornell Lab of Ornithology database, eBird, and the Global Biodiversity Information Facility, I examine whether species shifted their elevational ranges over time by comparing observed versus expected occurrences below a low elevational threshold and above a high elevational threshold for two periods: before and after 2005. I also test for deforestation effects at lower elevations within each species’ distribution ranges. Species’ retreats from lower elevations are ubiquitous and involve a 23–40% decline in prevalence at the lowest elevations. Increases at higher elevations are not consistent. The retreats occur across a broad spectrum of species, from predominantly lowland to predominantly highland. Because deforestation show no relationship with species retreats, I contend that a warming climate is the most parsimonious explanation for such shifts. In the second chapter, I identify priority range-restricted bird species and their conservation hotspots in the Northern Andes (Medina et al. 2024). I employ updated maps of Area of Habitat (AOH), following a protocol I contributed along a set of experts from the Cornell Lab, Birdlife International, and American Bird Conservancy (Huang et al. 2021). In this protocol, I was tasked to build R and Python scripts capable to handle crowd-sourced data and batch-generate habitat maps for a thousand birds across the Americas. With the updated maps of species distribution, I estimate protection within each species’ AOH and for the cumulative distribution of birds. For the latter, I also calculate protection across the elevational gradient. I estimate how much additional protection community lands (Indigenous and Afro-Latin American lands) would contribute if they were conservation-focused. AOHs ranged from 8 to 141,000 km2. I identify four conservation priorities based on cumulative species richness. These priorities are high-resolution mapped representations of Endemic Bird Areas for the Tropical Andes that should be considered critically important. Protected areas cover only 31% of the cumulative AOH, but community lands could add 19% more protection. Sixty-two per cent of the 335 species have ranges smaller than their published estimates, yet IUCN designates only 23% of these as Threatened. Top 50 priority species concentrate in areas of low protection near community lands and at middle elevations where, on average, only 34% of the land is protected. I highlight the importance of collaborative efforts among stakeholders: governments should support private and community-based conservation practices to protect the region with the most range-restricted birds worldwide. Private reserves hold promise for the restoration of degraded landscapes and the protection of fragmented animal populations. In the third chapter, I advocate for the creation and implementation of private reserves as concluded in the previous chapter, drawing upon a case study from the Eastern Andes of Colombia to illustrate their potential. This study examines the rehabilitation efforts spanning four decades within Rogitama, aiming to assess their impact on mammal diversity and composition (Medina et al. 2021). Findings reveal the presence of 22 species, predominantly bats and rodents. These results mirror biodiversity levels akin to those observed in less disturbed areas of the Eastern Cordillera, indicating promising advances in ecosystem recovery within the reserve. I posit Rogitama, as a noteworthy case of successful plant rejuvenation, highlighting its significance in the broader context of biological conservation efforts. I firmly advocate for stakeholders to take heed of this case study as a blueprint for development in Northern Andean regions, where I have previously identified critical conservation gaps and priorities. In the last chapter, I identify species and areas that urgently need exploration to increase knowledge on distribution limits (Medina et al. in prep). I consider the AOH where there is less probability of finding a target species given its closeness to non-detection areas. These non-detection areas have checklists where a target species has yet to be reported. The proportion of species absent from an area over the species present will result in relatively uncertain areas. To define potential exploration sites, I mapped these areas along cumulative AOH for 281 species. I found priority exploration areas (high richness and high relative uncertainty) are relatively small compared to non-priority areas. Since 2000, human impact has penetrated 8% of priority areas and allowed 8% of the areas to be studied. Deforestation has progressively reduced, but some countries are still dealing with it. Protection along the priority regions is low. It is essential that governments devote more efforts to exploring biodiversity to better understand patterns in species distribution and thus develop accurate conservation and management plans.

This dissertation consists of four chapters. The first three chapters examine protected areas (or parks) from multiple perspectives. Parks are the first, and often only, line of defense in efforts to conserve biodiversity. Understanding of their promise and problems is necessary to achieve conservation outcomes. Chapter One determines vegetation patterns in and around parks of differing management categories across the Amazon, Congo, South American Atlantic Coast, and West African forests. Within these forests, protected areas are the principle defense against forest loss and species extinctions. In the Amazon and Congo, parks are generally large and retain high levels of forest cover, as do their surroundings. In contrast, parks in the Atlantic Coast forest and West Africa show sharp boundaries in forest cover at their edges. This effective protection of forest cover is partially offset by their very small size: little area is deep inside park boundaries. Compared to West Africa, areas outside parks in the Atlantic Coast forest are unusually fragmented.

Chapter Two addresses a human dimension of protected areas. Given certain characteristics, parks areas may either attract or repel human settlement. Disproportionate increases in population growth near park boundaries may threaten their ability to conserve biodiversity. Using decadal population datasets, we analyze population growth across 45 countries and 304 parks. We find no evidence for population growth near parks to be greater than growth of rural areas in the same country. Furthermore, we argue that what growth does occur near parks likely results from a general expansion of nearby population centers. Parks may experience unusual population pressures near their edges; indeed, individual case studies provide examples. There is no evidence, however, of a general pattern of disproportionate population growth near their boundaries.

Chapter Three provides a review of common approaches to evaluating protection's impact on deforestation, identifies three hurdles to empirical evaluation, and notes that matching techniques from economic impact evaluation address those hurdles. The central hurdle derives from the fact that protected areas are distributed non-randomly across landscapes. Matching controls for landscape characteristics when inferring the impact of protection. Applications of matching have revealed considerably lower impact estimates of forest protection than produced by other methods. These results indicate the importance of variation across locations in how much impact protection could possibly have on rates of deforestation.

Chapter Four departs from the focus of protected areas and instead addresses a more theoretical aspect of community ecology. Ecological theories suggest that food webs might consist of groups of species forming blocks, compartments or guilds. Chapter Four considers ecological networks (subsets of complete food webs) involving species at adjacent trophic levels. Reciprocal specializations occur when (say) a pollinator (or group of pollinators) specializes on a particular flower species (or group of such species) and vice versa. We characterize the level of reciprocal specialization for various classes of networks. Our analyses include both antagonistic interactions (particularly parasitoids and their hosts), and mutualistic ones (such as insects and the flowers that they pollinate). We also examine whether trophic patterns might be palimpsests. That is, there might be reciprocal specialization within taxonomically related species within a network, but these might be obscured when these relationships are combined. Reciprocal specializations are rare in all these systems even when tested using the most conservative null model.

The protection of global biodiversity and the conservation of the earth’s natural resources are paramount to future wellbeing of mankind. Humans are a hugely influential part of the global ecosystem, and the ways in which we use, create, and change global biodiversity patterns are as important to understand as the ways in which those patterns function without our interference. Of more specific importance is an understanding of the ways in which human values, behaviors and practices (especially those surrounding leadership, management, and finance) relating to biodiversity management can be helpful or harmful as we attempt to meet our self-determined goals of global conservation.

To that end, the first chapter of this dissertation focuses on the potential influence of leadership and management on outcomes in wildlife reintroduction programs. Wildlife reintroductions and translocations are statistically unlikely to succeed. Nevertheless, they remain a critical part of conservation because they are the only way to actively restore a species into a habitat from which it has been extirpated. Past efforts to improve these practices have attributed the low success rate to failures in the biological knowledge (e.g., ignorance of social behavior, poor release site selection), or to the inherent challenges of reinstating a species into an area where threats have already driven it to local extinction. Such research presumes that the only way to improve reintroduction outcomes is through improved biological knowledge. This emphasis on biological solutions may have caused researchers to overlook the potential influence of other factors on reintroduction outcomes. I employed a grounded theory approach to study the leadership and management of a successful reintroduction program (the Sea Eagle Recovery Project in Scotland, UK) and identify four critical managerial elements that I theorize may have contributed to the successful outcome of this 50-year reintroduction. These elements are:

(i) Leadership & Management: Small, dedicated team of accessible experts who provide strong political and scientific advocacy (“champions”) for the project.

(ii) Hierarchy & Autonomy: Hierarchical management structure that nevertheless permits high individual autonomy.

(iii) Goals & Evaluation: Formalized goal-setting and regular, critical evaluation of the project’s progress toward those goals.

(iv) Adaptive Public Relations: Adaptive outreach campaigns that are open, transparent, inclusive (esp. linguistically), and culturally relevant.

This study represents an initial, but valuable inquiry into the ways in which leadership and management can impact programmatic (and therefore, biodiversity) outcomes.

The second chapter of this dissertation explores the potential relationship between financial mechanisms and outcomes in non-governmental biodiversity conservation programs. Although local laws, trends, and markets forces often shape the specific laws and market conditions under which conservation transactions occur, focusing analysis on the broader mechanisms of transfer may provide new opportunities to identify patterns, improve efficiency, and link transfer mechanisms to conservation outcomes.

Through a series of seven brief, descriptive case studies built around interviews with senior officers at US non-governmental organizations, this chapter seeks to highlight potential linkages between inflows of conservation dollars, financial mechanisms used to transfer them to conservation actors/entities/organizations, and eventual outflows of conservation dollars into measurable outcomes. This chapter also presents a preliminary framework for categorizing mechanisms and predicting their impacts on availability and outflow of conservation dollars. Although the framework fails to predict all outcomes, its failure highlights several emergent themes in the impact of financial mechanism, including:

(i) longer time horizons of funding availability can decrease the value of conservation investments, but increase accountability

(ii) time-bound (or time-limited) funding mechanisms can create uncertainty and decrease investment in program outcomes

(iii) mechanisms granting greater control to donors/investors can decrease the autonomy and adaptability of conservation organizations, and can skew outcomes toward donor biases

We hope that these results are useful as a first step toward the greater consideration of financial mechanisms in conservation planning and financial analysis.

The third chapter of this dissertation applies principles of the first two chapters as part of an in-depth look at one conservation initiative: the Anne K. Taylor Fund’s Boma Fortification Program, taking place in Narok County, Kenya. In the pastoral steppe of East Africa, lions (Panthera leo) kill livestock. The subsequent lethal retaliation by livestock owners has helped reduce lion numbers by more than 80% and driven it from most of its historic range. This conflict is especially intense along the western edge of the Maasai Mara National Reserve in Kenya, where some of the densest lion and livestock populations in Africa overlap.

We evaluated the efficacy and cost-effectiveness of implementation for one proposed solution – the Anne K. Taylor Fund’s subsidized construction of fortified, chain-link livestock fences (‘bomas’) – in reducing livestock loss to depredation. We collected 375 predation reports from 308 semi-structured household interviews and predation records. We used these data to study the impact of subsidised boma fortification on the depredation of cattle, sheep and goats. Of 179 fortified bomas, 67% suffered no losses over one year; of 60 unfortified bomas, only 15% had no losses over one year. Furthermore, losses of greater than five animals per year occurred at only 17% of fortified bomas, compared to 57% of unfortified bomas. The overall reduction in losses to predation at fortified bomas equated to savings of more than $1,200 USD per household per year, but with a return on investment of 778%, partially fortified bomas are vastly more cost effective than fully fortified bomas (return on investment = 349%).

However, the broad applicability of the boma fortification approach is uncertain, as its financial structure relies heavily on a single large donor to act as subsidizing entity. This single-supplier approach introduces cost inefficiencies, as well as supply chain vulnerabilities. Future fortification programs should consider alternative decentralized approaches to strengthen supply lines and scale the solution.

These chapters collectively represent a thorough examination of the human dimensions of conservation – and the ways in which leadership, management, finance, and valuation can contribute to harmful or helpful outcomes in the effort to preserve global biodiversity.