How to Excel in Conservation Biology

Abstract

Spreadsheet Exercises in Conservation Biology and Landscape Ecology. Donovan, T. M., and Welden, C. W. . 2002 . Sinauer Associates , Sunderland, MA . 464 pp. $24.95 (paperback ). ISBN 0-87893-159-7 . For the past 7 years, I have taught a course in conservation biology directed at upper-division undergraduates and graduate students in which the application of ecological theory and population genetics to conservation ( With 1997 ) is emphasized heavily. The course attracts a wide range of students from programs as diverse as biology, environmental science, fisheries and wildlife biology, forestry, resource management, and even the English and philosophy departments. The diverse composition of the class presents a special challenge in that many students are deficient in the basic tenets of ecological theory and genetics, or at least would benefit greatly from a review. Because theory provides the basis for developing models that are ultimately required for the assessment, diagnosis, prescription, and prognosis of problems in conservation ( e.g., Caswell 2001 ), a solid foundation in ecological theory and genetics is essential ( or should be ) to the curriculum of any course in conservation biology. Unfortunately, most general text books in conservation biology give short shrift to theory, emphasizing instead the principles and concepts that underlie conservation, backed by appropriate case studies to demonstrate their successful ( or not so successful ) application to various problems in conservation. Such an overview provides students with little opportunity to develop the necessary quantitative and problem-solving skills required for evaluating or resolving problems in conservation biology. Modeling helps facilitate a deeper understanding of the basic concepts and principles underlying conservation biology. Students in my course are therefore required to complete a number of assignments or projects designed to foster the development of these skills and to give them hands-on experience in applying theory and models to real problems in conservation. Up to now, only one lab manual in conservation biology has been available on the market ( Gibbs et al. 1998 ), and it provides a nice range of activities, a few of which even involve simulation models and quantitative analysis. Its main focus is not on the application of ecological theory or genetics to problems in conservation, however. To fill this void, I have resorted to developing my own exercises to illustrate theoretical applications and modeling approaches to conservation-related issues or have borrowed software and class projects developed by colleagues. In Spreadsheet Exercises in Conservation Biology and Landscape Ecology, Therese Donovan and Charles Weldin have developed 36 exercises involving basic spreadsheet applications that permit students to explore some of the main principles, theories, and models that provide the foundation of conservation science. The use of spreadsheets as a modeling tool, as opposed to a computer programming language or other commercially available modeling software, may at first appear an unusual choice. Although the spreadsheet exercises in this lab manual may not possess the “bells and whistles” of simulation-based models, with their flashy interactive graphics, they more than make up for this in terms of ease-of-use and accessibility to students. This is particularly advantageous for students with little or no programming experience or with little computer experience in general ( still an all-too-common problem in interdisciplinary courses that attract a diverse student body ). The lab manual is divided into three parts. The first consists of an introduction to spreadsheets and an additional six chapters devoted to mathematical functions and graphs, spreadsheet functions and macros, statistical distributions, the central-limit theorem, hypothesis testing, and sampling. The introduction provides a nice overview of the mechanics of spreadsheet use and procedures that are used in the various exercises throughout the text. This provides the necessary entrée into spreadsheets for the uninitiated and a useful review for students who already have some spreadsheet experience, especially with Microsoft Excel. ( Instructions throughout the manual are based on Excel, but should be generally applicable to other spreadsheet packages. ) The remaining chapters in this first section lay the foundation in mathematical functions and statistics that support the development and interpretation of models presented throughout the lab manual. Depending on the background and proficiency of students in the course, these first six exercises might be deemed essential or merely optional if required only for review. The meat of the lab manual is in the second section, which consists of nearly two dozen exercises devoted to a diverse array of theoretical applications and modeling approaches that address a wide range of problems in conservation biology. These include basic population models; age- and stage-structured matrix models ( including a chapter devoted to sensitivity and elasticity analysis ) and life-table analysis; metapopulation and source-sink dynamics; demographic stochasticity; population estimation and mark-recapture techniques; island biogeography; population viability analysis; and harvest models. Seven of the chapters in this section focus on genetic applications, including the use of the Hardy-Weinberg equilibrium equation to assess expected genotypic frequencies within populations, gene flow in spatially structured populations, measures of genetic diversity, effects of inbreeding and outbreeding on genotypic and phenotypic variation, effects of genetic drift on allelic diversity, and calculation of effective population size. The final section of the lab manual consists of seven exercises involving landscape ecological applications or conservation issues that require a landscape perspective. They include setting up a spreadsheet to generate random landscape patterns ( i.e., neutral landscape models ) for which various indices to quantify landscape structure are calculated manually; the use of neutral landscape models to define thresholds in landscape connectivity ( this exercise uses the product of another chapter that employs Visual Basic for Applications programming to analyze landscape structure and calculate basic landscape metrics ); evaluating the effect of landscape structure on dispersal success; exploring source-sink relationships for populations in landscapes consisting of varying amounts of core ( source ) and edge ( sink ) habitat; and designing reserves to optimize species richness. For a general course in conservation biology, these exercises effectively demonstrate the application to conservation of some of the basic concepts and tools of landscape ecology. For a course in landscape ecology, however, the recent lab manual edited by Gergel and Turner ( 2001 ) is a better choice because it offers greater coverage and presents a wide variety of techniques, including software on the accompanying CD, for the generation and analysis of complex landscape patterns ( which cannot be done within the constraints of a spreadsheet ) and for exploring the full range of ways in which landscape structure affects ecological processes. Each chapter in Spreadsheet Exercises in Conservation Biology and Landscape Ecology is formatted to provide a series of clearly stated objectives, suggested preliminary exercise( s ) to be completed before attempting the current exercise ( if necessary ), a brief introduction that sets the stage for the exercise, and an explanation of the exercise's relevance to conservation. Each is followed by a description of the details of setting up the spreadsheet and developing the model and concludes with a series of questions to provide students with additional opportunities to explore the consequences of the model they have developed. In addition, abbreviated directions are provided in the left margin of each chapter. Students are encouraged to try to use these annotated instructions to work through the problem of model development on their own, in the hopes that they will learn more about the process and achieve a better understanding as a consequence. Many students will nevertheless be tempted to tackle these exercises in cookbook fashion, blindly following the detailed instructions for each step. Such students should be warned that there are some typographical errors in the text ( e.g., an incorrect cell address in the construction of some formula or incorrect graph axes or labels ) that will lead to erroneous calculations and other problems if they do not understand the logic behind what they are attempting to do. Furthermore, some of the exercises are math-intensive ( e.g., the chapters devoted to matrix population models or using a matrix approach to calculate reproductive values ), which is likely to intimidate many students ( especially because these types of classes may be composed of students with poor quantitative skills in the first place ) and again force them to adopt a cookbook approach toward the exercises. Because of the variety of topics covered, however, an instructor can easily select which chapters to assign to meet the needs and ability of students in the class. The time required to complete an individual exercise varies, but the student should plan on about 1.5 hours, with an additional hour or so to address the questions at the end of each chapter. Thus, some additional time outside class may be required to complete these exercises if they are done as part of a 2-hour lab complement to a conservation course. Alternatively, exercises could be assigned as out-of-class projects, given that many students have access to spreadsheet software either on their home computers or through computers available on campus. Spreadsheet Exercises in Conservation Biology and Landscape Ecology thus provides a nice complement to a general text in conservation biology but is not meant to be a substitute. Ideally, the basic concept, theory, or technique explored in each exercise should be discussed first in lecture to establish a conservation-related context for the application. Although not without limitations, the use of spreadsheets provides a surprisingly effective way for students to develop quantitative and problem-solving ( i.e., modeling ) skills in a way that will be accessible and understandable to most students. I therefore anticipate adopting this lab manual as a supplementary text in my conservation biology course, and I recommend it to other instructors whose curriculum likewise emphasizes the importance of theory and modeling for addressing problems in conservation and who are similarly dealing with the challenge of presenting and developing such skills among a diverse student body that a course in conservation biology inevitably attracts.