Sensitivity analysis of a migratory population of Redshanks Tringa totanus: a forewarning of a population decline?
2005 (English)In: Wader Study Group Bulletin, ISSN 0260-3799, Vol. 107, 40-45 p.Article in journal (Refereed) Published
Several wader species breeding in agricultural landscapes are declining in Europe. Here, we present evidencethat reproduction in a subpopulation of an abundant but vulnerable wader species, the Redshank Tringa totanus,is too low for self-sustainability. We used population data collected from Gotland, SE Sweden, during thebreeding seasons of 1997–2003. We used analytic and simulation-based sensitivity analyses of a stage-basedmatrix model of female Redshanks to compare the relative importance of specific vital rates to λ (populationgrowth rate). For each vital rate, we present estimates of mean values and parameter limits. At mean valuesof vital rates, λ is estimated to 0.876, while the computer simulation yields an average λ of 0.860 (95% confidenceintervals: 0.770–0.950), which is significant lower than 1. Further, analytic sensitivity of λ is highestto adult survival followed by chick survival and nest success. Analytic elasticity of λ ranks vital rates in a similarway as analytic sensitivity, and the computer simulation also indicates that the rankings of sensitivities andelasticities are robust to parameter uncertainties. In the simulated data, almost half of the variation in λ wasexplained by variation in adult survival (41%). The explanatory power of chick survival (27%) and nest successof first clutches (22%) was intermediate while other vital rates accounted for negligible amounts of variation.We conclude, however, that the potential to increase an already high adult survival is limited. Therefore,management actions should aim to increase reproductive success mediated via decreased nest predationrates and increased survival of Redshank chicks simultaneously.
Place, publisher, year, edition, pages
Ebford: Wader Study Group , 2005. Vol. 107, 40-45 p.
shorebird, Redshank, Tringa totanus, population dynamics, demography
Research subject Biology
IdentifiersURN: urn:nbn:se:hgo:diva-148OAI: oai:DiVA.org:hgo-148DiVA: diva2:248954