Erik Solbu

Postdoktor

(+47) 975 84 012
erik.solbu@nibio.no

Sted
Trondheim

Besøksadresse
Klæbuveien 153, bygg C 1.etasje, 7031 Trondheim

Til dokument

Sammendrag

There has been much recent research interest in the existence of a major axis of life‐history variation along a fast–slow continuum within almost all major taxonomic groups. Eco‐evolutionary models of density‐dependent selection provide a general explanation for such observations of interspecific variation in the "pace of life." One issue, however, is that some large‐bodied long‐lived “slow” species (e.g., trees and large fish) often show an explosive “fast” type of reproduction with many small offspring, and species with “fast” adult life stages can have comparatively “slow” offspring life stages (e.g., mayflies). We attempt to explain such life‐history evolution using the same eco‐evolutionary modeling approach but with two life stages, separating adult reproductive strategies from offspring survival strategies. When the population dynamics in the two life stages are closely linked and affect each other, density‐dependent selection occurs in parallel on both reproduction and survival, producing the usual one‐dimensional fast–slow continuum (e.g., houseflies to blue whales). However, strong density dependence at either the adult reproduction or offspring survival life stage creates quasi‐independent population dynamics, allowing fast‐type reproduction alongside slow‐type survival (e.g., trees and large fish), or the perhaps rarer slow‐type reproduction alongside fast‐type survival (e.g., mayflies—short‐lived adults producing few long‐lived offspring). Therefore, most types of species life histories in nature can potentially be explained via the eco‐evolutionary consequences of density‐dependent selection given the possible separation of demographic effects at different life stages.

Sammendrag

Denne pilotstudien er gjennomført på oppdrag av Miljødirektoratet. Formålet har vært å teste ut og videreutvikle en overvåkningsmetodikk for semi-naturlig eng som ble publisert av NIBIO i 2017. Det var ønskelig at metodikken for semi-naturlig eng (ASO, Arealrepresentativ overvåkning av seminaturlig eng i Norge) skulle samsvare med og utfylle ANO (Arealrepresentativ naturovervåkning i Norge). Pilotstudien og uttestingen av metodikken ble gjennomført i to observasjonsområder, ett i Nordland (Alstadhaug) og ett i Trøndelag (Stjørdal). I rapporten beskrives det hvilke justeringer og tilpasninger det anbefales å gjøre for å tilpasse ASO til ANO, hvilke deler av metodikken som bør være forskjellig.