Large delay in flowering in continental versus coastal populations of a Mediterranean shrub, Globularia alypum

Temperate deciduous shrub phenology: the overlooked forest layer

Temperate deciduous shrub phenology plays a pivotal role in forest ecology by regulating the timing of suitable habitat and food of a range of organisms as well as influencing the timing and duration of the carbon uptake period especially in early spring and late autumn when trees are leafless. However, given the overwhelming influence of canopy trees on forest ecosystem functioning, shrubs are often ignored in ecosystem modeling. Isolating the shrub contribution to C flux or satellite-derived forest phenology is challenging. In addition, since shrubs are more likely to be invasive than trees, future changes to shrub species composition are likely, with consequent implications for both over- and understory species composition and ecosystem functioning. Surprisingly, given their multifaceted role, our review revealed that studies on temperate deciduous shrub phenology are limited with the majority focusing on managing invasive shrubs in USA forests. In addition, results of some studies using a large number of species from a range of geographical locations suggested that, in general, invasive shrubs leafed out earlier and retained leaves longer than native species. However, this may not be directly applicable to local conditions with a smaller range of locally adapted species. Therefore, in order to fully understand the role of shrub phenology in temperate deciduous forests, in terms of invasive species, response to climate change and subsequent influence on C balance it will be necessary to establish phenological monitoring sites in which both tree and shrub phenology are recorded concurrently across a range of geographical locations.

A novel sunshine duration-based photothermal time model interprets the photosensitivity of flower maturity of pecan cultivars

Although it is well-known and established that light plays important roles in plant development, up to now, there is no substantial improvements in how to deal with the light factor of spring phenology under natural condition. By monitoring the local meteorologic data and mature dates of two types (male and female) of flower from four pecan cultivars during 9 years, it was found that the complementary pattern of growing degree day and sunshine duration helped to maintain a threshold of driving force related to the maturity of pecan flower during 9 years. A novel photothermal time model based on the linear combination of growing degree day and sunshine duration was then proposed and validated to interpret the variance of mature dates of pecan cultivars. Comparative analysis showed that the new model had made extremely significant improvements to the traditional thermal time model. In addition, this model introduced the conversion coefficient K, which quantified the effect of light on the flowering drive, and revealed the differences of base temperature among cultivars. This was the first time that sunshine duration instead of photoperiod was adopted to develop into a verified model on spring phenological event of tree species. It will help to model the spring phenologies of other tree species more reasonably.

The rise of phenology with climate change: an evaluation of IJB publications

In recent decades, phenology has become an important tool by which to measure both the impact of climate change on ecosystems and the feedback of ecosystems to the climate system. However, there has been little attempt to date to systematically quantify the increase in the number of scientific publications with a focus on phenology and climate change. In order to partially address this issue, we examined the number of articles (original papers, reviews and short communications) containing the terms 'phenology' and 'climate change' in the title, abstract or keywords, published in the International Journal of Biometeorology in the 60 years since its inception in 1957. We manually inspected all issues prior to 1987 for the search terms and subsequently used the search facility on the Web of Science online database. The overall number of articles published per decade remained relatively constant (255-378) but rose rapidly to 1053 in the most recent decade (2007-2016), accompanied by an increase (41-172) in the number of articles containing the search terms. A number of factors may have contributed to this rise, including the recognition of the value of phenology as an indicator of climate change and the initiation in 2010 of a series of conferences focusing on phenology which subsequently led to two special issues of the journal. The word 'phenology' was in use from the first issue, whereas 'climate change' only emerged in 1987 and peaked in 2014. New technologies such as satellite remote sensing and the internet led to an expansion of and greater access to a growing reservoir of phenological information. The application of phenological data included determining the impact of warming of phenophases, predicting wine quality and the pollen season, demonstrating the potential for mismatch to occur and both reconstructing and forecasting climate. Even though this analysis was limited to one journal, it is likely to be indicative of a similar trend across other scientific publications.