Temporal trends in pollination of the Oleaceae family.
| Reference (publication date) | Region (number of sites) | Study period | Methodology | Trend identification technique | PIn (grains per cubic meter of air per decade and significance) | PSS (days per decade and significance) | PSD (days per decade and significance) | |
|---|---|---|---|---|---|---|---|---|
| [18] (2014) | Europe (13) | 1990–2009 | Hirst-type | Linear regression | + in 7 sites of 10 (ns), + in Madrid (**) | – or + (ns) | – in 7 sites of 10 (ns, except Derby **) | |
| [51] (2024) | NE Italy (20) | 2001–2022 | Hirst-type | Theil-Sen estimator | + (646) | – (13.5) | + (13.3) | |
| Olea | ||||||||
| [20] (2010) | NW Italy (1) | 1981–2007 | Hirst-type | Linear regression | + (*) | – (17.0; *) | + (6.7) | |
| [36] (2016) | Spain (12) | 1994–2013 | Hirst-type | Linear regression | + at 6 sites out of 9 (~12,900 in Córdoba) | |||
| [52] (2021) | France (2) | 1995–2019 | Hirst-type | Variable | + (~350) at Aix-en-Provence; no trend at Toulon | |||
| [56] (2012) | Europe (97) | 1977–2009 (partially) | Hirst-type | Linear regression | + (ns) | |||
| [74] (2025) | Iberian Peninsula (12) | 1994–2023 | Hirst-type | Linear regression | + (3,778 on average, but up to 11,940 in Jaén) | Slightly + (1.6) | ||
| [82] (2024) | Rome (1) | 1997–2016 | Hirst-type | Reduced major axis linear regression | + (ns) | |||
| [83] (2002) | Central Italy (1) | 1982–2001 | Hirst-type | Linear regression | – (4.0; *) | – (5.0; *) | ||
| [89] (2024) | Madrid region (10) | 1994–2022 | Hirst-type | Linear regression | + (at least locally) | |||
| [90] (2024) | N Italy (1) | 1989–2018 | Hirst-type | Linear regression + Mann-Kendall test | + (**) | |||
| [91] (2016) | S Spain (1) | 1996–2010 | Hirst-type | Linear regression + local regression method (LOESS) | + (~190,000; ***) | |||
| [93] (2023) | Andalusia (1) | 1998–2020 | Hirst-type | Linear regression + Mann-Kendall test + Sen’s slope estimation | + (3,830; ns) | – (0.8; ns) | ||
| [94] (2018) | S Spain (1) | 1994–2016 | Hirst-type | Z coefficient estimation + Mann-Kendall test | + (~14,500; **) | – (ns) | + (~13.0; *) | |
| [95] (2022) | Madrid (1) | 1979–2018 | Hirst-type | Linear regression | No trend | – (~1.75) | ||
| [96] (2025) | SW Spain (1) | 1993–2022 | Hirst-type | Linear regression + Mann-Kendall test + Theil-Sen estimator | + (1,668 to 1,808; **) | – (1.6; ns) | – (1.9; **) | |
| [99] (2014) | S Spain (1) | 1982–2011 | Hirst-type | Linear regression + seasonal-trend decomposition procedure based on LOESS + ARIMA model | + (~7,000; ***) | – (~3.6; ns) | + (~11.9; ***) | |
| [100] (2011) | NW Italy (1) | 1981–2010 | Hirst-type | Linear regression | + (***) | No trend | No trend | |
| [102] (2013) | Spain (4) & Italy (6) | 1992–2011 | Hirst-type | Unspecified | – (especially 2004–2011, and in Italy more than in Spain) | |||
| 2046–2065 | Thermal time model | – | ||||||
| [103] (2005) | Andalusia (5) | 1982–2001 | Hirst-type | – (4; *), but + in Cordoba (4) | ||||
| 2000s–2099 | Growing degree-days | – (0.3 to 2.4) | ||||||
| [104] (2024) | Barcelona (1) | 2000–2019 | Hirst-type | + (1.2; ns) | ||||
| 2024–2100 | Forecast model of the PSS + climate scenarios | – (depending on the climate scenario) | ||||||
| [105] (2015) | Spain (4) & Italy (6) | 2081–2100 vs. 1993–2011 | Pheno-meteorological models | – (~0.9 to 1.1) | ||||
| [106] (2012) | Calabria (3) | 21st century | Phenological model | – (1.0 to 3.4) | ||||
| [107] (2013) | Central and S Italy (16) | 2050 | Model | – (2 to 19, mean 8, with 1°C of warming) | ||||
| [108] (2000) | W Mediterranean | 1990s–2030s | Phenological model | – (0.6 to 1.6) | ||||
| Fraxinus | ||||||||
| [24] (2005) | Austria in valley area (1) | 1980–2001 | Hirst-type | Linear regression | + (~950) | – (3.2) | ||
| [25] (2018) | Brussels (1) | 1982–2015 | Hirst-type | Local regression method (LOESS) | + | |||
| [26] (2003) | Switzerland (1) | 1979–1999 | Hirst-type | Linear regression | No trend | – (14.3; *) | No trend | |
| [27] (2025) | Texas, USA (1) | 2009–2023 | Hirst-type | Least square regression | + (ns) | |||
| [28] (2021) | Benelux (5) | 1981–2020 | Hirst-type | Linear regression | + in all sites; * in 4 of 5 | – in 4 sites of 5; * in only 1 | + (* at just 1 site out of 5); – (* at another site) | |
| [36] (2016) | Spain (12) | 1994–2013 | Hirst-type | Linear regression | + at 7 sites out of 8; – in Madrid (ns) | |||
| [37] (2021) | Basel (1) | 1969–2018 | Hirst-type | Linear regression | + (~588; **) | – (~3.7; **) | – (~3; **) | |
| [38] (2021) | Switzerland (14) | 1990–2020 | Hirst-type | Linear regression + LOESS | + (ns) | No trend | – (*) | |
| [40] (2018) | Brussels (1) | 1982–2015 | Hirst-type | Linear regression + Mann-Kendall test | + (*) | – (ns) | ||
| [45] (2011) | S Poland (1) | 1991–2008 | Hirst-type | Linear regression | + (*) | No trend | ||
| [47] (2021) | Bavaria (8) | 1989–2018 | Hirst-type | Linear regression | + | |||
| [56] (2012) | Europe (97) | 1977–2009 (partially) | Hirst-type | Linear regression | + (***) | |||
| [73] (2002) | W of the NL (1) | 1969–2000 | Hirst-type | Linear regression | – (1, ns) | |||
| 2000s–2090s | Modelling | Unspecified | – (1.9) | |||||
| [82] (2024) | Rome (1) | 1997–2016 | Hirst-type | Reduced major axis linear regression | + (ns) | |||
| [86] (2020) | Andalusia (3) | 1994–2017 | Hirst-type | Linear regression | + (especially in Granada; ns) | – (* in Córdoba, ns elsewhere) | ||
| [89] (2024) | Madrid region (10) | 1994–2022 | Hirst-type | Linear regression | + (at least locally) | |||
| [94] (2018) | S Spain (1) | 1994–2016 | Hirst-type | Z coefficient estimation + Mann-Kendall test | + (~30; **) | – (ns) | + (~20; *) | |
| [109] (2019) | NW Spain (1) | 1997–2016 | Hirst-type | Mann-Kendall test + Theil-Sen estimator | + (~100; **) | |||
| [110] (2024) | Slovakia (2) | 2002–2022 | Hirst-type | Linear regression + Mann-Kendall test + Theil-Sen estimator | + (ns) | – (ns) | ||
| [111] (2002) | Switzerland | 1951–2000 | Hirst-type + phenology | – (~6) | ||||
The grey backgrounds correspond to studies that have made projections about the future. +: trend towards increased pollen concentration (Pin), earlier onset of pollination (PSS), or longer pollen season (PSD); –: trend towards decreased pollen concentration (PIn), later onset of pollination (PSS), or shorter pollen season (PSD); *: p < 0.05; **: p < 0.01; ***: p < 0.001. PIn: pollen integral; PSS: pollen season start date; PSD: pollen season duration; ns: non-significant; NE: northeast; NW: northwest; N: north; S: south; LOESS: locally estimated scatterplot smoothing; SW: southwest; ARIMA: autoregressive integrated moving average; W: west; NL: Netherlands.