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Long-term phenological shifts in raptor migration and climate.

Jaffré M, Beaugrand G, Goberville E, Jiguet F, Kjellén N, Troost G, Dubois PJ, Leprêtre A, Luczak C - PLoS ONE (2013)

Bottom Line: Climate change is having a discernible effect on many biological and ecological processes.We found that when the temperatures increased, birds delayed their mean passage date of autumn migration.Such delay, in addition to an earlier spring migration, suggests that a significant warming may induce an extension of the breeding-area residence time of migratory raptors, which may eventually lead to residency.

View Article: PubMed Central - PubMed

Affiliation: Centre National de la Recherche Scientifique, Laboratoire d'Océanologie et de Géosciences UMR LOG CNRS 8187, Université Lille 1, Station Marine de Wimereux, Wimereux, France.

ABSTRACT
Climate change is having a discernible effect on many biological and ecological processes. Among observed changes, modifications in bird phenology have been widely documented. However, most studies have interpreted phenological shifts as gradual biological adjustments in response to the alteration of the thermal regime. Here we analysed a long-term dataset (1980-2010) of short-distance migratory raptors in five European regions. We revealed that the responses of these birds to climate-induced changes in autumn temperatures are abrupt and synchronous at a continental scale. We found that when the temperatures increased, birds delayed their mean passage date of autumn migration. Such delay, in addition to an earlier spring migration, suggests that a significant warming may induce an extension of the breeding-area residence time of migratory raptors, which may eventually lead to residency.

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Effect of the abrupt shifts in autumn temperatures on the timing of migration.A, mean anomalies of autumn temperatures and Mean Passage Date (MPD; in day) for all periods revealed by the Rodionov’s test (see Figure 2). Both autumn temperatures and MPD are expressed in anomalies with respect to the period 1980-2010. b, c, d, Repartition of the anomalies of MPD during (B) the first period 1980-1994 (T1=12.29°C), (C) the second period 1995-2006 (T2=12.91°C) and (D) the third period 2007-2010 (T3=12.66°C).
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pone-0079112-g004: Effect of the abrupt shifts in autumn temperatures on the timing of migration.A, mean anomalies of autumn temperatures and Mean Passage Date (MPD; in day) for all periods revealed by the Rodionov’s test (see Figure 2). Both autumn temperatures and MPD are expressed in anomalies with respect to the period 1980-2010. b, c, d, Repartition of the anomalies of MPD during (B) the first period 1980-1994 (T1=12.29°C), (C) the second period 1995-2006 (T2=12.91°C) and (D) the third period 2007-2010 (T3=12.66°C).

Mentions: We applied the Rodionov's sequential algorithm to detect the temporal discontinuities (1980-2010) occurring in the first PCs originating from the PCA performed on post-breeding migration (Figure 3A and Figure S1A), autumn temperatures (Figure 3C) and spring temperatures (Figure S1C). We used a first-order autoregressive model to consider temporal autocorrelation [24], a probability threshold of p=0.1 and cut-off length of l=10 to control the magnitude and the scale of the shift, respectively. To consider outliers above 1 standard deviation, the Huber's weight parameter was fixed to h=1. As guidance for choosing parameters p and l, setting parameters were adjusted following the recommendations of previous studies to detect shifts with meaningful environmental and biological implications [24-26]. The choice of a significance level p=0.1 is a good compromise between robustness of the detected shift and the flexibility of the detection [24,25]. A cut-off length of l=10 discounts regimes of shorter length to detect only statistically significant long regime shifts depending on the studied period (i.e. 30 years - [26]). A Huber parameter of h=1 is such that the number of detected shifts remains stable for higher values of h. More details about the methods and parameters it takes can be found at www.beringclimate.noaa.gov/regimes/. The magnitude of the shifts was subsequently quantified by selecting Sweden and Pyrenees (Table 1), sub-regions for which complete datasets exist for all considered raptors. For each regime, MPD anomalies were assessed for every year and species with respect to the period 1980-2010. A histogram was then calculated to reveal the statistical distribution of all anomalies for each regime (Figure 4). The average anomalies of autumn temperatures and post-breeding migration were also assessed for each regime (Figure 4A).


Long-term phenological shifts in raptor migration and climate.

Jaffré M, Beaugrand G, Goberville E, Jiguet F, Kjellén N, Troost G, Dubois PJ, Leprêtre A, Luczak C - PLoS ONE (2013)

Effect of the abrupt shifts in autumn temperatures on the timing of migration.A, mean anomalies of autumn temperatures and Mean Passage Date (MPD; in day) for all periods revealed by the Rodionov’s test (see Figure 2). Both autumn temperatures and MPD are expressed in anomalies with respect to the period 1980-2010. b, c, d, Repartition of the anomalies of MPD during (B) the first period 1980-1994 (T1=12.29°C), (C) the second period 1995-2006 (T2=12.91°C) and (D) the third period 2007-2010 (T3=12.66°C).
© Copyright Policy
Related In: Results  -  Collection

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getmorefigures.php?uid=PMC3815123&req=5

pone-0079112-g004: Effect of the abrupt shifts in autumn temperatures on the timing of migration.A, mean anomalies of autumn temperatures and Mean Passage Date (MPD; in day) for all periods revealed by the Rodionov’s test (see Figure 2). Both autumn temperatures and MPD are expressed in anomalies with respect to the period 1980-2010. b, c, d, Repartition of the anomalies of MPD during (B) the first period 1980-1994 (T1=12.29°C), (C) the second period 1995-2006 (T2=12.91°C) and (D) the third period 2007-2010 (T3=12.66°C).
Mentions: We applied the Rodionov's sequential algorithm to detect the temporal discontinuities (1980-2010) occurring in the first PCs originating from the PCA performed on post-breeding migration (Figure 3A and Figure S1A), autumn temperatures (Figure 3C) and spring temperatures (Figure S1C). We used a first-order autoregressive model to consider temporal autocorrelation [24], a probability threshold of p=0.1 and cut-off length of l=10 to control the magnitude and the scale of the shift, respectively. To consider outliers above 1 standard deviation, the Huber's weight parameter was fixed to h=1. As guidance for choosing parameters p and l, setting parameters were adjusted following the recommendations of previous studies to detect shifts with meaningful environmental and biological implications [24-26]. The choice of a significance level p=0.1 is a good compromise between robustness of the detected shift and the flexibility of the detection [24,25]. A cut-off length of l=10 discounts regimes of shorter length to detect only statistically significant long regime shifts depending on the studied period (i.e. 30 years - [26]). A Huber parameter of h=1 is such that the number of detected shifts remains stable for higher values of h. More details about the methods and parameters it takes can be found at www.beringclimate.noaa.gov/regimes/. The magnitude of the shifts was subsequently quantified by selecting Sweden and Pyrenees (Table 1), sub-regions for which complete datasets exist for all considered raptors. For each regime, MPD anomalies were assessed for every year and species with respect to the period 1980-2010. A histogram was then calculated to reveal the statistical distribution of all anomalies for each regime (Figure 4). The average anomalies of autumn temperatures and post-breeding migration were also assessed for each regime (Figure 4A).

Bottom Line: Climate change is having a discernible effect on many biological and ecological processes.We found that when the temperatures increased, birds delayed their mean passage date of autumn migration.Such delay, in addition to an earlier spring migration, suggests that a significant warming may induce an extension of the breeding-area residence time of migratory raptors, which may eventually lead to residency.

View Article: PubMed Central - PubMed

Affiliation: Centre National de la Recherche Scientifique, Laboratoire d'Océanologie et de Géosciences UMR LOG CNRS 8187, Université Lille 1, Station Marine de Wimereux, Wimereux, France.

ABSTRACT
Climate change is having a discernible effect on many biological and ecological processes. Among observed changes, modifications in bird phenology have been widely documented. However, most studies have interpreted phenological shifts as gradual biological adjustments in response to the alteration of the thermal regime. Here we analysed a long-term dataset (1980-2010) of short-distance migratory raptors in five European regions. We revealed that the responses of these birds to climate-induced changes in autumn temperatures are abrupt and synchronous at a continental scale. We found that when the temperatures increased, birds delayed their mean passage date of autumn migration. Such delay, in addition to an earlier spring migration, suggests that a significant warming may induce an extension of the breeding-area residence time of migratory raptors, which may eventually lead to residency.

Show MeSH
Related in: MedlinePlus