Data from: Cold tadpoles from Arctic environments waste less nutrients – high gross growth efficiencies lead to low consumer-mediated nutrient recycling in the North

1. Endothermic organisms can adapt to short growing seasons, low
temperatures and nutrient limitation by developing high growth rates and
high gross growth efficiencies (GGEs). Animals with high GGEs are better
at assimilating limiting nutrients and thus should recycle (or lose) fewer
nutrients. Longer guts in relation to body mass may facilitate higher GGE
under resource limitation. 2. Within the context of ecological
stoichiometry theory, this study combines ecology with evolution by
relating latitudinal life-history adaptations in GGE, mediated by gut
length, to its ecosystem consequences, such as consumer-mediated nutrient
recycling. 3. In common garden experiments, we raised Rana temporaria
tadpoles from two regions (Arctic/Boreal) under two temperature regimes
(18/23 °C) crossed with two food quality treatments (high/low-nitrogen
content). We measured tadpole GGEs, total nutrient loss (excretion +
egestion) rates and gut length during ontogeny. 4. In order to maintain
their elemental balance, tadpoles fed low-nitrogen (N) food had lower N
excretion rates and higher total phosphorous (P) loss rates than tadpoles
fed high-quality food. In accordance with expectations, Arctic tadpoles
had higher GGEs and lower N loss rates than their low-latitude
conspecifics, especially when fed low-N food, but only in ambient
temperature treatments. Arctic tadpoles also had relatively longer guts
than Boreal tadpoles during early development. 5. That temperature and
food quality interacted with tadpole region of origin in affecting tadpole
GGEs, nutrient loss rates and relative gut length, suggests evolved
adaptation to temperature and resource differences. With future climate
change, mean annual temperatures will increase. Additionally, species and
genotypes will migrate north. This will change the functioning of Boreal
and Arctic ecosystems by affecting consumer-mediated nutrient recycling
and thus affect nutrient dynamics in general. Our study shows that evolved
latitudinal adaption can change key ecosystem functions.