Document: SAL-3-82-33

Patterns of fluctuating asymmetry and genetic diversity across the distribution range: A focus on ecotones.

KARK, S.* ^1,2, U.N.SAFRIEL ¹, I.NOY-MEIR ¹ and E.RANDI ³

The Hebrew University of Jerusalem, Jerusalem 91904, Israel ¹
Stanford University, Stanford, CA 94305 USA ²
Istituto Nazionale per la Fauna Selvatica, Ozanno dell'Emilia (BO), Italy ³

Abstract:
There is a long-lasting debate whether populations from geographically peripheral areas across a species' distribution differ from those located further away from the periphery of the range in: 1) Within-population genetic and morphological diversity; 2) environmental and genetic stress which individuals confront during development. The latter can be estimated by levels of bilateral fluctuating asymmetry (FA). FA reflects the ability of individuals to develop in the face of stress. We suggest that a focus on areas of transition between ecological systems, ecotones, may partly resolve the above controversy. Focusing on the chukar partridge (Alectoris chukar) in Israel as a research model, we compared genetic (allozyme) diversity in 13 populations across a steep gradient from the arid periphery, through the Mediterranean-desert ecotone towards mesic areas away from the periphery. Populations were sampled in areas with minimum modern human-related activity, and were compared with populations from adjacent human-dominated regions. Genetic diversity across the native populations studied showed a hump-shaped pattern, peaking at the ecotone. FA of the third toe length was examined as it showed high measurement repeatability. Mean FA significantly increased towards the periphery, especially at the ecotone, where asymmetry shifted from fluctuating to directional and antisymmetrical. This provides first evidence for shifts between asymmetry types within a species' range. Trends in asymmetry across the distribution range of other species, including Pierid butterflies (Euchloe) and Pistacia trees in Israel, Hawaiian honeycreepers and African passerines, are currently being studied to test the generality of these trends. We aim to examine the usefulness of asymmetry as a tool for conservation biology in the face of changing environments and climate changes. Following the "representation approach" to conservation of biodiversity, we suggest that further research attention should be directed towards areas of transition. In the chukar case study, this area was shown to be the most representative, as well as a hot-spot of genetic and morphological diversity and of endemic genotypes. We are currently comparing the findings with a similar distribution gradient for the chukar partridge in Eastern Gansu, China.

Keywords: biodiversity conservation, birds, fluctuating asymmetry, developmental instability, representation approach

This abstract is being presented at: 3:30 PM in session:
CONSERVATION ECOLOGY