Spatio-temporal Functional Regression on Paleo-ecological Data

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📝 Original Info

  • Title: Spatio-temporal Functional Regression on Paleo-ecological Data
  • ArXiv ID: 0807.2588
  • Date: 2008-07-17
  • Authors: Researchers from original ArXiv paper

📝 Abstract

The influence of climate on biodiversity is an important ecological question. Various theories try to link climate change to allelic richness and therefore to predict the impact of global warming on genetic diversity. We model the relationship between genetic diversity in the European beech forests and curves of temperature and precipitation reconstructed from pollen databases. Our model links the genetic measure to the climate curves through a linear functional regression. The interaction in climate variables is assumed to be bilinear. Since the data are georeferenced, our methodology accounts for the spatial dependence among the observations. The practical issues of these extensions are discussed.

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Deep Dive into Spatio-temporal Functional Regression on Paleo-ecological Data.

The influence of climate on biodiversity is an important ecological question. Various theories try to link climate change to allelic richness and therefore to predict the impact of global warming on genetic diversity. We model the relationship between genetic diversity in the European beech forests and curves of temperature and precipitation reconstructed from pollen databases. Our model links the genetic measure to the climate curves through a linear functional regression. The interaction in climate variables is assumed to be bilinear. Since the data are georeferenced, our methodology accounts for the spatial dependence among the observations. The practical issues of these extensions are discussed.

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arXiv:0807.2588v1 [stat.AP] 16 Jul 2008 Spatio-temp oral F un tional Regression on P aleo-e ologi al Data Liliane Bel ∗ , UMR 518 A gr oParisT e h/INRA,16, rue Claude Bernar d - 75231 Paris Ce dex 05 A vner Bar-Hen, Université R ené Des artes, MAP5, 45 rue des Saints Pèr es, 75270 Paris

e dex 06 Ra hid Cheddadi, ISEM,

ase p ostale 61, CNRS UMR 5554, 34095 Montp el lier, F r an e Rém y P etit, UMR 1202 INRA , 69 r oute d’A r

a hon 33612 Cestas Ce dex, F r an e Abstra t The inuen e of limate on bio div ersit y is an imp ortan t e ologi al question. V ari- ous theories try to link limate

hange to alleli ri hness and therefore to predi t the impa t of global w arming on geneti div ersit y . W e mo del the relationship b e- t w een geneti div ersit y in the Europ ean b ee h forests and urv es of temp erature and pre ipitation re onstru ted from p ollen databases. Our mo del links the geneti measure to the limate urv es through a linear fun tional regression. The in tera - tion in limate v ariables is assumed to b e bilinear. Sin e the data are georeferen ed, our metho dology a oun ts for the spatial dep enden e among the observ ations. The pra ti al issues of these extensions are dis ussed. Key wor ds: F un tional Data Analysis; Spatio-temp oral mo deling; Climate

hange; Bio div ersit y Preprin t submitted to Elsevier No v em b er 18, 2018 1 In tro du tion 1 Climate re ords sho w that the earth has re orded a su ession of p erio ds of 2 ma jor w arming and o oling at dieren t time windo ws and s ales [5 , 12℄. During 3 the last p ost-gla ial p erio d (18000 y ears b efore the presen t), Europ e re orded 4 a 15◦ C to 20◦ C w arming dep ending on the area. A t the same p erio d there w as 5 an expansion of all forest biomes and an up w ard mo v emen t of the tree-lines 6 that rea hed an altitude 300 m higher than to da y . Although there is a w ealth 7 of paleo data and detailed limate re onstru tion for the Holo ene p erio d, w e 8 still la k some kno wledge as to ho w the w arming w as re orded and what the 9 v egetation feedba ks w ere that ae ted lo al or regional past limates. V arious 10 theories try to link limate

hange to alleli ri hness and therefore to predi t 11 the impa t of global w arming on geneti div ersit y . 12 In the re en t literature there ha v e b een a lot of theoreti al results for regres- 13 sion mo dels with fun tional data. Based on this framew ork, w e used a linear 14 fun tional mo del to mo del the relationship b et w een geneti div ersit y in Euro- 15 p ean b ee h forests (represen ted b y a p ositiv e n um b er) and urv es of temp er- 16 ature and pre ipitation re onstru ted from the past. The lassi al fun tional 17 regression mo del has b een extended in t w o w a ys to a oun t for our sp e i 18 problem. First, as the ee ts of temp erature and pre ipitation are far from 19 indep enden t w e in luded an in tera tion term in our mo del. This in tera tion 20 term app ears as a bilinear fun tion of the t w o predi tors. Se ond, sin e w e 21 ha v e spatial data there is dep enden e among the observ ations. T o tak e in to 22 a oun t with dep enden e the o v arian e matrix of the residuals is estimated 23 in a spatial framew ork and plugged in to generalized least-squares to estimate 24 the parameters of the mo del. The pra ti al di ulties of these extensions will 25 b e dis ussed. 26 In Se tion 2, w e presen t the geneti and limate data. The fun tional regression 27 mo del is studied in Se tion 3. Results are presen ted and dis ussed in Se tion 4 28 ∗ Corresp onding author. Email addr ess: Liliane.Bel agropariste h.fr (Liliane Bel). 2 and on luding remarks are giv en in Se tion 5. 1 2 Data 2 P ollen re ords are imp ortan t pro xies for the re onstru tion of limate param- 3 eters sin e v ariations in the p ollen assem blages mainly resp ond to limate 4

hanges. Based on the fossil and surfa e p ollen data from p ollen databases, 5 w e used mo dern analogue te hnique (MA T) to re onstru t limate v ariables. 6 Climate re onstru tion is a omplished b y mat hing fossil biologi al assem- 7 blages to re en tly dep osited (mo dern) p ollen assem blages for whi h limate 8 prop erties are kno wn. The relatedness of fossil and mo dern assem blages is usu- 9 ally measured using a distan e metri that res ales m ultidimensional sp e ies 10 assem blages in to a single measure of dissimilarit y . The distan e-metri metho d 11 is widely used among paleo e ologists and paleo eanographers [8℄. T emp erature 12 and pre ipitation w ere re onstru ted at 216 lo ations from the presen t ba k 13 to a v ariable date dep ending on a v ailable data. The p ollen dataset w as used 14 to re onstru t limate v ariables, throughout Europ e for the last 15 000 y ears 15 of the Quaternary . Due to the metho dology , ea h limate urv e is sampled at 16 irregular times for ea h lo ation. 17 Geneti div ersities w ere measured from v ariation at

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