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Free keywords:
δ¹³C; δ¹⁵N; niche overlap; reproductive isolation; resource competition; stable isotope analysis; stomach content analysis; sympatric species
Abstract:
Hypothesis: Ecological specialization facilitates co-existence of Coregonus spp. in Lake Stechlin. A difference in trophic ecology is the dominant means by which the species are ecologically segregated.
Background: Sympatric fish species pairs in post-glacial lakes often feed on different resources, segregating available trophic resources.
Organisms: Sympatric European winter-spawning Coregonus albula and the local endemic dwarf-sized spring-spawning Coregonus fontanae.
Time and place: March-December 2005, Lake Stechlin, North Germany.
Methods: By combining stomach content analyses and stable isotope analyses we compared consumption patterns of the two species at different depths over a 10-month period.
Results: Stable isotope analyses and stomach content analyses both showed little trophic difference between the two species, but a significant effect of capture depth and body size on individual diet.
Conclusions: The sympatric species pair in Lake Stechlin does not follow the expected pattern of niche segregation. Trophic divergence is not the dominant grounds for co-existence.
