Congruence Among Taxonomic Groups Biol2559/22/2003 Brooke Wheeler

Importance of congruence Studying biodiversity limited by time, expertise, and resources Studying biodiversity limited by time, expertise, and resources Patterns and levels of congruence are central questions Patterns and levels of congruence are central questions Congruence and endemism could be key in conservation and research efforts (Gaston 1996) Congruence and endemism could be key in conservation and research efforts (Gaston 1996) Taxa as predictors are suggested as an alternative to single species predictors (Allen et al. 2001) Taxa as predictors are suggested as an alternative to single species predictors (Allen et al. 2001)

Support in ecological theory? (Vessby et al. 2002) Species rich areas support more species at high taxon levels Species rich areas support more species at high taxon levels As area increases, richness does as well As area increases, richness does as well Different habitat requirements and limitations Different habitat requirements and limitations Different scale dependencies Different scale dependencies Effects of habitat fragmentation Effects of habitat fragmentation

Congruence: the overlap of high species richness for one taxon with areas that have a high richness for another taxon. Coincidence of diversity in space. Highest for ecologically and phylogenetically related groups. Gaston (1996) Photo from Peter White

Complementarity While congruence of richness looks at coincidence of diversity, complementarity takes into account the identity of the diversities While congruence of richness looks at coincidence of diversity, complementarity takes into account the identity of the diversities Principle in selection for efficient conservation Principle in selection for efficient conservation Maximize richness, with the smallest number of areas Maximize richness, with the smallest number of areas Examples of 2 extremes: Examples of 2 extremes: –2 areas, equal diversity– the same assemblages –2 areas, equal diversity– no overlapping species

Uganda example Groups of priority sites determined based on “Indicator taxon” Groups of priority sites determined based on “Indicator taxon” Woody plants, large moths, butterflies, birds and small mammals in 50 forests studied Woody plants, large moths, butterflies, birds and small mammals in 50 forests studied Different forests types are complementary Different forests types are complementary Priority sets represent other taxa effectively Priority sets represent other taxa effectively (Howard et al. 1998)

Sub-Saharan Africa 6 charismatic mammal flagship species 6 charismatic mammal flagship species Found that selection of areas for these species did not capture more diversity of other taxa of mammals and birds than selecting areas at random Found that selection of areas for these species did not capture more diversity of other taxa of mammals and birds than selecting areas at random Representation of diversity is dependent on low overlap in distribution and occurrence in several ecoregions Representation of diversity is dependent on low overlap in distribution and occurrence in several ecoregions (Williams et al. 2000)

Northern European freshwater systems Macrophytes, dragonflies, stoneflies, dytiscid beetles and teleost fishes Macrophytes, dragonflies, stoneflies, dytiscid beetles and teleost fishes Strong levels of congruence Strong levels of congruence Large-scale geography and climate have strong effects at local and provincial scales Large-scale geography and climate have strong effects at local and provincial scales Limits of species pools important to understanding assemblages Limits of species pools important to understanding assemblages (Heino 2001)

Mammals and Ants in S. Florida Using Gap Analysis, vertebrate species richness to predict overall biological diversity (depends on congruence of species diversity) Using Gap Analysis, vertebrate species richness to predict overall biological diversity (depends on congruence of species diversity) Found congruence but in low to medium diversity areas (low congruence of high diversity areas) Found congruence but in low to medium diversity areas (low congruence of high diversity areas)

Vessby et al No significant congruence of richness No significant congruence of richness Most obvious reason for covariation of richness is habitat dependency Most obvious reason for covariation of richness is habitat dependency Difficult to select indicator taxa Difficult to select indicator taxa Plants and butterflies are positively correlated; birds and dung beetles are negatively correlated Plants and butterflies are positively correlated; birds and dung beetles are negatively correlated

Lund & Rahbek 2002 Patterns of congruence depend on scale and fragmentation Patterns of congruence depend on scale and fragmentation Taxon with the lowest species was the best predictor Taxon with the lowest species was the best predictor –Lower overlap in ranges because of habitat fragmentation –Represent other taxa well

Bats, butterflies, and large moths are effective indicators. Birds have highest richness but do not function well as an indicator taxon. All taxa represented other groups better than random selections of area.

Is the biodiversity of different taxa correlated? If so, is this pattern strong enough to make using congruence practical in predicting diversity? Should a taxon be used as a proxy for diversity of other taxa in conservation planning? What factors influence these patterns?