Latitudinal, longitudinal and weather-related variation in breeding parameters of Great Reed Warblers in Europe: a meta-analysis

Abstract

Clutch size generally decreases with latitude from the poles towards the Equator (Bell 1996, 38 Sanz 1999, Cardillo 2002, Cooper et al. 2005, Jetz et al. 2008, Griebeler et al. 2010, Winkler 39 et al. 2014. Griebeler et al. (2010) and Jetz et al. (2008) The Great Reed Warbler Acrocephalus arundinaceus, a western Palearctic species breeding in 57 reed Phragmites australis habitats, is suitable for such investigations because its breeding 58 biology is well described from several locations in Europe (Fig. 1). Latitudinal gradient found 59 in avian clutch size (Jetz et al. 2008, Griebeler et al. 2010 The results of the analyses showed that the best one-term model for mean clutch initiation 109 date contained the term Longitude, whereas four of the five best two-term models also 110 included Longitude (Table 1) The two best one-term models for mean clutch size were either with Maximum Temperature 118 or Latitude, and these variables were part of a number of two-term models for mean clutch 119 size ( Table 1). The effect of Latitude was positive (Table 2) (Table 1). Again, the effects of Latitude and Longitude were positive 128 (Table 2), indicating more fledglings at more northern and eastern localities, whereas that of 129 Maximum Temperature was negative, indicating fewer fledglings in localities with higher 130 maximum temperatures in the hottest month (Fig. 4, linear regression, F 1,15 = 8.9, p < 0.01). 131Maximum Temperature was frequent in the best models (appearing in 9 of 10 best models, In conclusion, we found that clutch initiation date was earlier in more eastern sites and that its

<p class="NoSpacing1">THE EFFECTS OF WEATHER AND REED MANAGEMENT ON NESTING PARAMETERS OF THE GREAT REED WARBLER, ACROCEPHALUS ARUNDINACEUS (AVES: SYLVIIDAE)

“…However, such climatic impacts have not only effects in a local population of a species; the weather influences nesting success of birds along latitudinal and longitudinal geographical gradients (e.g. Cooper et al 2005, Mérő et al 2015a. Beside weather circumstances, ecological disturbances can change ecosystem and community structure, and influence resources, substrate availability and/or the physical environment (White & Pickett 1985).…”

Ashmole's hypothesis and the latitudinal gradient in clutch size

“…Many papers confuse the resource seasonality (intra‐annual variation) that underlies Ashmole's mechanism with other sources and scales of environmental variability, including: inter‐annual variability (Gibb, 1968) or stochasticity (Møller, 1984), productivity (Thomas et al ., 1999), absolute food availability (Simmons, 1993; Li & Lu, 2012; Mérő, Žuljevic & Lengyel, 2015), environmental variability (Engen & Saether, 2016), stability, or predictability (Horn, 2012). Many of these works (Gibb, 1968; Tarburton, 2009; Burski, 2011; Gill & Haggerty, 2012; Horn, 2012; Heming & Marini, 2015) equate or conflate Ashmole's mechanism with Cody's (1966, 1971) hypothesis to explain clutch size evolution and the mechanism underlying r ‐ K selection theory (MacArthur, 1962; Pianka, 1970), on which Cody's ideas were directly based.…”