The paper: Predicting potential cambium damage and fire resistance in Pinus nigra Arn. ssp. salzmannii by: ESPINOSA, J.; RODRÍGUEZ DE RIVERA, O.; MADRIGAL, J.; GUIJARRO, M; HERNANDO, C. , has just been published in Forest Ecology and Management.

Abstract:

Fire management can play a key role in ensuring stand maintenance in future scenarios of global change, particularly in Pinus nigra stands, which are known to be adapted to low-intensity surface fires through characteristics such as thick bark. In this study, laboratory tests were carried out to quantify cambium damage and fire resistance in P. nigra, by using a mass loss colorimeter device in a vertical configuration for the first time. In addition, low-intensity prescribed burning treatments were conducted in the field, and the field and laboratory data were compared. The following variables were used as proxy measures to assess cambium damage: time that temperature remained above 60 °C, heating rate and maximum absolute temperature in the inner bark area. The data were analysed using a Bayesian hierarchical approach (generalized linear mixed model). A threshold heat flux (25 kW m^-2) for the time to ignition of bark was identified. A critical temperature of 60 °C was reached in the cambium during the combustion phase, after the flame was extinguished. The laboratory experiments showed, for the first time, the influence of flame residence time on the potential cambium damage. A bark thickness of 17 mm can be considered the threshold level for preventing critical temperatures being reached in Pinus nigra stands. The influence of bark thickness on protection against fire was confirmed, as was the importance of the coefficient of variation of bark thickness. The field results showed that flame characteristics (maximum temperature and residence time) were the most significant predictors of cambium damage. The combination of fire intensity and exposure time at low heat fluxes is more important than bark in determining cambium damage and may have important implications in the field of forest fuel management and in the ecology of pine forests.

The statistical ecology group from Kent (SE@K) attended the first virtual international statistical ecology conference (vISEC) from 22nd June to 26th June.

Fabian, Katie Oscar and James gave contributed talks. Fabian talked about Objective Priors from Scoring rules for N-mixture models. Katie  gave a talk on Mark-recapture modelling to inform conservation management in Mauritius. Oscar talked about Assessing the Spatio-Temporal distribution of invasive species. James gave the talk Modelling butterfly lifespans using citizen-science count data.

The paper: Duration of female parental care and their survival in the little auk Alle alle – are these two traits linked? by: Katarzyna Wojczulanis-Jakubas, Marina Jiménez-Muñoz, Dariusz Jakubas, Dorota Kidawa, Nina Karnovsky, Diana Cole and Eleni Matechou, has just been published in Behavioral Ecology and Sociobiology.

Abstract:

Desertion of offspring before its independence by one of the parents is observed in a number of avian species with bi-parental care but reasons for this strategy are not fully understood. This behaviour is particularly intriguing in species where bi-parental care is crucial to raise the brood successfully. Here, we focus on the little auk, Alle alle, a small seabird with intensive bi-parental care, where the female deserts the brood at the end of the chick rearing period. The little auk example is interesting as most hypotheses to explain desertion of the brood by females (e.g. “re-mating hypothesis”, “body condition hypothesis”) have been rejected for this species. Here, we analysed a possible relationship between the duration of female parental care over the chick and her chances to survive to the next breeding season. We performed the study in two breeding colonies on Spitsbergen with different foraging conditions – more favourable in Hornsund and less favourable in Magdalenefjorden. We predicted that in Hornsund females would stay for shorter periods of time with the brood and would have higher survival rates in comparison with birds from Magdalenefjorden. We found that indeed in less favourable conditions of Magdalenefjorden, females stay longer with the brood than in the more favourable conditions of Hornsund. Moreover, female survival was negatively affected by the length of stay in the brood. Nevertheless, duration of female parental care over the chick was not related to their parental efforts, earlier in the chick rearing period, and survival of males and females was similar. Thus, although females brood desertion and winter survival are linked, the relationship is not straightforward.

Diana Cole’s book Parameter Redundancy and Identifiability has been publish by Chapman and Hall/CRC

Book Synopsis

Statistical and mathematical models are defined by parameters that describe different characteristics of those models. Ideally it would be possible to find parameter estimates for every parameter in that model, but, in some cases, this is not possible. For example, two parameters that only ever appear in the model as a product could not be estimated individually; only the product can be estimated. Such a model is said to be parameter redundant, or the parameters are described as non-identifiable. This book explains why parameter redundancy and non-identifiability is a problem and the different methods that can be used for detection, including in a Bayesian context. Key features of this book:

• Detailed discussion of the problems caused by parameter redundancy and non-identifiability
• Explanation of the different general methods for detecting parameter redundancy and non-identifiability, including symbolic algebra and numerical methods
• Chapter on Bayesian identifiability
• Throughout illustrative examples are used to clearly demonstrate each problem and method. Maple and R code are available for these examples
• More in-depth focus on the areas of discrete and continuous state-space models and ecological statistics, including methods that have been specifically developed for each of these areas

This book is designed to make parameter redundancy and non-identifiability accessible and understandable to a wide audience from masters and PhD students to researchers, from mathematicians and statisticians to practitioners using mathematical or statistical models.

Book website: https://www.routledge.com/Parameter-Redundancy-and-Identifiability/Cole/p/book/9781498720878

Code for book available at: https://www.kent.ac.uk/smsas/personal/djc24/parameterredundancy.html

Congratulations to Rachel for her well-deserved promotion to professor, congratulations Professor McCrea!

SE@K had a meal at Cafe Des Amis in Canterbury to celebrate recent successes of the group:

Rachel being awarded Guy Bronze Medal ; Byron being awarded the Barnett award ; Eleni being awarded £303 200 by NERC for the project “Integrating new statistical frameworks into eDNA survey and analysis at the landscape scale”

Rachel has been awarded the 2020 Guy Bronze Medal by the Royal Statistical Society (RSS).

The Guy Medal in Bronze has been awarded for her innovative and novel work in statistical ecology, with particular reference to the development of goodness-of-fit tests and model selection strategies for complex ecological data. Important areas include (multi-state) capture-recapture-type models and integrated models. Notable publications include: the 2017 JRSSC paper ‘A new strategy for diagnostic model assessment in capture-recapture’, which identified a direct relationship between particular diagnostic tests and score tests; and the 2020 JRSSC paper ‘Diagnosing heterogeneity in transition probabilities in multistate capture-recapture data’, which developed new tests to identify unmodelled transition heterogeneity.

Professor Deborah Ashby, President of the Royal Statistical Society, said: “Dr McCrea has made a profound contribution to statistical ecology. The Society’s journals have published a number of noteworthy papers authored by Rachel, and her development of goodness-of-fit tests and model selection strategies has been particularly innovative.”

The medal will be presented to Rachel at the RSS Annual Conference in Bournemouth in September.