Biological Richness, An Introduction

1. Biological Richness, An Introduction James A. Danoff-Burg Dept. Ecol., Evol., & Envir. Biol. Columbia University

2. Today: Introduction to Biological Richness • Designing Surveys – Review of assignment 1 • Why Study Biological Diversity? • Types & Aspects of Diversity • Evenness • Species Richness Indices • Rarefaction © 2003 Dr. James A. Danoff-Burg, jd363@columbia.edu

3. Application of Techniques – An Exercise • Design a study, avoiding pseudoreplication • Include visual representations of sampling method • Include: • Experimental question • Manipulations • Hypotheses (null, alternatives) • Target organisms • Censusing design • Censusing method © 2003 Dr. James A. Danoff-Burg, jd363@columbia.edu

4. Last Week’s Assignment • Project of your own design • Write up a short (2-3 paragraphs) description of your proposed study in normal scientific prose • Include question and hypotheses (including null and all alternative hypotheses) • Include sampling design, sampling method • Be specific and thorough • Email to jd363@columbia.edu before the start of class next week © 2003 Dr. James A. Danoff-Burg, jd363@columbia.edu

5. Types of Censusing Designs • Grid • Using regular intervals along a 2-dimensional design • Transect • Sampling with reference to a straight line • Random • Can be used to site point-quarters, quadrats, other sampling methods © 2003 Dr. James A. Danoff-Burg, jd363@columbia.edu

6. Choosing Between Censusing Designs • How to choose between sampling layouts? • Depends on experimental question • Gradients • Probably best to use a transect • Ensures comparability • Relatively uniform sampling area • Random probably best – if done frequently enough, get equal representation of areas included • Grid may be useful when need to uniformly sample area © 2003 Dr. James A. Danoff-Burg, jd363@columbia.edu

7. Surveying Design • Need to equally capture / census entire community (or subset) to be studied • Be consistent • Have equal sampling effort in different areas • Time, area, quantity sampled • Appropriately represent area studied • Equally sample disparate constituent areas • Random vs. orderly (grid, transect)? © 2003 Dr. James A. Danoff-Burg, jd363@columbia.edu

8. Surveying Techniques • In short: Any viable form of collecting or sampling • Need to be sited at a level appropriate to the question • Examples: • Point-Quarter • Proximity to a central point within a cross • Quadrat • Sampling within a small area • Pitfall traps • Beating Sheets • Mist netting • Seining • Etc… © 2003 Dr. James A. Danoff-Burg, jd363@columbia.edu

9. Pseudoreplication Example Treatment A Treatment B • Question – What is the affect of treatments A & B? • Pseudoreplication = treating stars of the same color as replicates • Replication = include only a single star of each color, or their average Site 3 Site 1 Site 2 Site 4 © 2003 Dr. James A. Danoff-Burg, jd363@columbia.edu

10. Today: Introduction to Biological Richness • Designing Surveys – Review of assignment 1 • Why Study Biological Diversity? • Types & Aspects of Diversity • Evenness • Species Richness Indices • Rarefaction © 2003 Dr. James A. Danoff-Burg, jd363@columbia.edu

11. Diversity is Interesting • Stimulated many poets, artists, naturalists, etc. • Ecotourism is prompted by biological diversity • Or at least biological, geological, climatological diversity • Continual novelty is a key feature • Increasing probability of novelty, because of high biodiversity, leads to increasing visitation rates • E.g., most ecotourism is to tropics © 2003 Dr. James A. Danoff-Burg, jd363@columbia.edu

12. Diversity as an Indicator • Diversity = health of the ecosystem • Diversity and stability relationship • Example of Shahid Naeem’s work on trophic redundancy and stability • Diversity and recovery from perturbations, erosion, etc. • Diversity as a detective tool of the past • Use to determine how long ago land was altered by human or natural activity © 2003 Dr. James A. Danoff-Burg, jd363@columbia.edu

13. Diversity is controversial • Define diversity • Simple definitions work well • Richness • Abundance • BUT these are not really “Diversity” • More complicated ones are less clear • What does it mean? • More we try to define it, the less definable it is • Some have argued that it is meaningless (Hurlbert 1971) © 2003 Dr. James A. Danoff-Burg, jd363@columbia.edu

14. Today: Introduction to Biological Richness • Designing Surveys – Review of assignment 1 • Why Study Biological Diversity? • Types & Aspects of Diversity • Evenness • Species Richness Indices • Rarefaction © 2003 Dr. James A. Danoff-Burg, jd363@columbia.edu

15. Types of Biological Diversity • Point: diversity at a single point or microenvironment • Alpha: within habitat diversity • Beta: species diversity along transects & gradients • High Beta indicates number of spp increases rapidly with additional sampling sites along the gradient • Gamma: diversity of a larger geographical unit (island) • Epsilon: regional diversity © 2003 Dr. James A. Danoff-Burg, jd363@columbia.edu

16. Aspects of Biodiversity • What can we measure? • Possibilities • Species (richness) • Abundance • Diversity • relationship between richness & abundance • Guild • Trophic structure • Evolutionary diversity • Within species diversity (genetic, morphological) • Others? © 2003 Dr. James A. Danoff-Burg, jd363@columbia.edu

17. Diversity of Diversities • Difference between the diversities is usually one of relative emphasis of two main envir. aspects • Two key features • Richness • Abundance • Each index differs in the mathematical method of relating these features • One is often given greater prominence than the other • Formulae significantly differ between indices © 2003 Dr. James A. Danoff-Burg, jd363@columbia.edu

18. Today: Introduction to Biological Richness • Designing Surveys – Review of assignment 1 • Why Study Biological Diversity? • Types & Aspects of Diversity • Evenness • Species Richness Indices • Rarefaction © 2003 Dr. James A. Danoff-Burg, jd363@columbia.edu

19. Evenness • Definition of Evenness • How equally abundant are each of the species? • A simple way to combine abundance and richness • Rarely are all species equally abundant • Some are better competitors, more fecund, more abundant in general than others © 2003 Dr. James A. Danoff-Burg, jd363@columbia.edu

20. Evenness increases diversity • Increasing evenness greater diversity • True for all indices S = 4 N = 8 S = 4 N = 8 Higher Evenness, Diversity Site 2 Site 1 © 2003 Dr. James A. Danoff-Burg, jd363@columbia.edu

21. Evenness as an Indicator • For many ecosystems, high evenness is a sign of ecosystem health • Don’t have a single species dominating the ecosystem • Often invasives dominate • Paradox of enrichment • E.g., polluted / enriched Lake Okeechobee, Florida • Disturbed areas are mostly edge species • Simple biodiversity • Dominance of a few species ecologically, numerically © 2003 Dr. James A. Danoff-Burg, jd363@columbia.edu

22. Evenness Across Locations • Between ecosystem comparability is usually not possible • Some areas have lower biodiversity naturally than others • Tiaga is naturally much less even than the deciduous forest • Tiaga is often dominated by a single species (e.g., Blue Spruce) • Seasonality may confound the comparison as well • Earlier in temperate growing season, less even than later • This is a general principle for most all indices this term • When would you want to compare across locations? • Trying to prioritize areas for conservation • Based largely on biodiversity (not ecol. uniqueness) © 2003 Dr. James A. Danoff-Burg, jd363@columbia.edu

23. Today: Introduction to Biological Richness • Designing Surveys – Review of assignment 1 • Why Study Biological Diversity? • Types & Aspects of Diversity • Evenness • Species Richness Indices • Rarefaction © 2003 Dr. James A. Danoff-Burg, jd363@columbia.edu

24. Species Richness Indices • Richness has largely been the variable of interest for many conservationists • There are many ways to treat species richness • Two main ones • Raw Richness • Species Density © 2003 Dr. James A. Danoff-Burg, jd363@columbia.edu

25. Numerical species richness = Raw Richness • Works best with complete surveys (everything taken) • These can be destructive • Need equal sampling effort • Popular in aquatic studies • species seen per 1000 individuals © 2003 Dr. James A. Danoff-Burg, jd363@columbia.edu

26. Species Density • Useful in botanical surveys, sometimes in aquatic surveys • Species / m2 if on a 2D plane • Mostly botanical surveys, some arthropod surveys • Species / m3 if in a 3D space • Aquatic or botanical canopy surveys © 2003 Dr. James A. Danoff-Burg, jd363@columbia.edu

27. Today: Introduction to Biological Richness • Designing Surveys – Review of assignment 1 • Why Study Biological Diversity? • Types & Aspects of Diversity • Evenness • Species Richness Indices • Rarefaction © 2003 Dr. James A. Danoff-Burg, jd363@columbia.edu

28. Rarefaction • Method to post-hoc treat data to correct for lack of standardization of sampling effort • Not always possible to collect in a standardized manner • Particularly true with “Natural Experiments” • May have some treatment areas larger than others • Able to collect in some areas for more time than others • Outcome • To calculate the # of spp expected in each sample • If hypothetically, all samples were of a standard size © 2003 Dr. James A. Danoff-Burg, jd363@columbia.edu

29. Rarefaction • Designed by Sanders (1968), modified by Hurlbert (1971) • Drawbacks • Loss of information through data loss • Expected number of abundance / species is all that is left • Loss of abundance, richness data • See Worked example #1 in Magurran for more information on how to do the calculation • We will work through this next week • Read the example before hand © 2003 Dr. James A. Danoff-Burg, jd363@columbia.edu

30. After Standardizing Efforts • Can now conduct simple richness comparisons between sites • Need to be comparable • Can do Margalef, Menhinick, Shannon, Simpson analyses • We’ll begin these in two weeks © 2003 Dr. James A. Danoff-Burg, jd363@columbia.edu

31. Our Data This Term I • Relationship between plant biodiversity, pest insect biodiversity, and beneficial insect biodiversity • Read website at http://www.columbia.edu/itc/cerc/danoff-burg/web-pages/gardens_main.htm • Has a pretty good amount of background on the topic • Field sites were in Manhattan and Brooklyn community gardens • Data collected during summer 2001 • I will also email you the data matrix • Please begin looking it over so that you are comfortable with it © 2003 Dr. James A. Danoff-Burg, jd363@columbia.edu

32. Our Data This Term II • Influence of Hemlock Woolly Adelgid on carrion beetle biodiversity • Separated by many (at least 3) trophic levels • Adelgid is a phloem-feeding insect • Carrion beetles are detritivores or predators on fly larvae on carrion • Field sites at Black Rock Brook, Black Rock Forest • Data collected during summer 2001 • I will also email you these data • Please begin looking over the data set © 2003 Dr. James A. Danoff-Burg, jd363@columbia.edu

33. Next week: • Abundance, An Introduction • Read • Magurran Ch 2 • Magurran Worked Examples 1-6 • Southwood & Henderson 2.1, 2.2, 13.1 • We will conduct a few evenness and species abundance models next week • Decide which of the two projects on which you are interested in working collaboratively • 3 people per group © 2003 Dr. James A. Danoff-Burg, jd363@columbia.edu