SLOSS debate reserve design principles

• “Single large or several small” • Debate over reserve design

SLOSS debate- criticisms Caribbean Anolis

• Pattern not always supported • Other factors may explain diversity • Close-site problems (synchrony) • Don’t take species identity into consideration (and trophic levels) • At particular sizes, no more species are added • Patches more connected than assumed, function of matrix

Losos and Schluter (2000) Nature

Habitat heterogeneity and species diversity The species-area relationship on islands Habitat heterogeneity and species diversity

Species 1 What is the relationship between habitat heterogeneity Variance = x and island area?

Species 1 • However, the species- Variance ≈ x area relationship is not always linear Species 2 Species 1

Variance = (n)x

Courtesy of Jason Knouft Courtesy of Jason Knouft

1 Caribbean habitat data Shifting paradigms…..

• In 1980’s, under heavy criticism of TIB, metapopulation theory becomes the dominant theory Elevation Temperature • Shift from community level to population level approach

Landcover Precipitation Courtesy of Jason Knouft

Metapopulations Metapopulations

• Population of populations • r -- % occupancy • Migration and extinction drive population • b – colonizations dynamics • d – extinctions • Variations • Examples

Metapopulations Variations

P = 1 – e/c •Simple: e = extinctions (true metapopulation) c = colonizations • Source-sink: Patch occupancy increases with decreasing e/c • Patchy population:

2 Examples Examples

• California mountain • California sheep checkerspot butterfly

Metacommunity Local Communities • Definition: A set of local communities linked by dispersal of • competition multiple potentially • predation interacting species (Leibold et al. 2004) • disturbances • abiotic factors • Two distinct community scales: Local and Regional

Species-specific traits Regional Community (trade-offs) • coexistence at • dispersal local and • patch regional heterogeneity community scales • predicts type of species expected

3 Trade-off examples Dispersal Frequency and Diversity (based on Mouquet and Loreau 2002)

Richness

Kneitel and Chase (2004) Ecology Letters

Regional Dynamics: Regional Dynamics: Experimental Design Local Richness

6 b X 3 Resource levels b X 2 Predator levels a X 3 Dispersal rates X 5 Replicates 3

measured protozoan Local species richness 0 abundance and richness None Low High Dispersal frequency

Kneitel and Miller (2003) American Naturalist

Regional Dynamics: Regional Dynamics: Protozoan Regional Diversity Protozoan Abundance

2.5 b b

a 2 Square root root Square

(regional richness) (regional 1.5 None Low High Dispersal frequency

Kneitel and Miller (2003) American Naturalist Kneitel and Miller (2003) American Naturalist

4 Regional Dynamics: Protozoan Local Diversity Empirical Examples

Harrison 1997, 1999 Shurin 2001, Cottenie et al. 2003

Bengtsson 1991, Lei and Hanski 1998, Therriault and Kolasa 2000 Amarasekare 2000 Kneitel and Miller (2003) American Naturalist

How do communities change with time?? Types of Succession

• Succession • Primary succesion (where no life existed before) •Sere • Types of Succession

1895 1999 Rotmoos Glacier on the Austria-Italian border

Secondary succession (Post-disturbance) Bog succession

5 Disturbance Disturbances

an event that removes biomass from a community • Gaps in rain forest a disturbance will start/restart succession to an • floods in floodplain (Mississippi) earlier stage • boulder rolling through the intertidal zone •fire • unusual severe weather - or long term aberrant trend •?

Clearwater Riparian Area 1981 1982

1983 1984

6 1987 Pioneer species

organisms that arrive early in succession

Pioneer Species Climax vegetation • r species • produce many small seeds, the final stage of a successional may form a process, usually defined by the seed bank habitat type • poor competitors • good colonizers

Climax Species Succession on Rocks

• K species • produce few large seeds, no seed bank • good competitors • poor colonizers

7 Soil development

Superorganism vs Individualistic (Clement 1936) (Gleason 1939)

8 Rivet Model Species Redundancy

• Paul and Anne Ehrlich (1981) • Walker (1991) • Species like rivets in airplane wings • Species and ecological processes • Not all necessary to hold wings together, redundant in community but enough loss (species) will result in it • Those species lost will be replaced by falling apart (ecosystem functioning) others with similar function (guilds or functional groups)

9