DOI: 10.5061/dryad.4j0zpc8jz
title: Tracking climate vulnerability across spatial distribution and functional traits in Magnolia gentryi from the Peruvian tropical montane cloud forest

description: Understanding the responses of tree species' functional traits to
 climate variability is essential for predicting the future of Tropical
 Montane Cloud Forest (TMCF) tree species through acclimation, especially
 in Andean montane environments where fog pockets act as moisture
 traps. We studied the distribution of Magnolia gentryi to measure
 its spatial arrangement and identify local hotspots, while also evaluating
 the extent to which climate-related factors are associated with its
 distribution. Finally, we analyzed variations in 13 functional traits of
 M. gentryi and the climate links to infer the shaping plant acclimate
 capacity. Our results show that Andean TMCF climatic factors
 constrain M. gentryi spatial distribution with significant patches or
 gaps, associated with high precipitation rates and mean minimum
 temperature. The functional traits of M. gentryi are constrained by Andean
 TMCF climatic factors, resulting in reduced within-species acclimation in
 functional traits associated with a hydric deficit. The
 association between functional traits and climate oscillation is crucial
 for understanding the growth conditions of relict-endemic species and is
 essential for conservation efforts. Changes in forest trait diversity and
 species composition occur because of fluctuations in hydraulic
 safety–efficiency gradients.
description: <em>Study species— Magnolia gentryi </em>A.Vázquez
 (Section <em>Talauma</em>, Magnolioideae, Magnoliaceae), is an
 endangered-evergreen Peruvian TMCF (Rivers et al. 2016) relict-tree
 species which only occurs in the Southeastern Tropical Andes
 (Vázquez-García et al. 2012). This species inhabits moderate steep-slope
 ravines and in valley bottoms and occasionally hilltops in association
 with <em>Hyeronima macrocarpa </em>Müll. Arg.,
 <em>Juglans neotropica</em>, <em>Cecropia</em>
 spp., <em>Clusia</em> spp., <em>Inga</em> spp.,
 <em>Hedyosmum scabrum </em>(Ruiz & Pav.) Solms,
 <em>Guatteria</em> sp., <em>Socratea</em> sp., and
 <em>Podocarpus</em> sp<em>.</em>
 <em>Site characteristics— </em>The study forest is in
 a TMCF fragment close to the Tsachopen native community in Oxapampa
 Province, Oxapampa District, Perú (10° 32’ 17’’S, 75° 27’ 05’’W; from 1800
 to 2000 m asl; 765 ha;). Nevertheless, TMCF is influenced by human
 activities such as logging, corn, coffee, and granadilla
 (<em>Passiflora ligularis</em> Juss.) plantations. The study
 forest has a temperate climate (Cwb; Peel et al. 2006), with rainy and
 cool summers, followed by mild and wet winters. Moisture levels of 75-90%
 are the result of frequent drizzles and fog throughout the year (Myster
 2021). Soil is Andosol (Th) with silicate-rich material under acid
 weathering (IUSS Working Group WRB. 2015). The studied forest represents
 an isolated distribution of endangered <em>Magnolia
 gentryi.</em> <em>Magnolia
 gentry</em> fieldwork survey<em>— </em>We conducted
 field surveys in the study forest from 2020 to 2022 to investigate the
 presence of the uncommon <em>Magnolia gentryi</em> in Peruvian
 TMCFs. All the <em>Magnolia</em> trees (20 individuals) were
 geo-referenced with a GPS (Garmin eTrex® 10; Garmin Ltd., Olathe, KS, USA)
 (Figure 1B). <em>Anatomical functional trait
 assessment</em><em>— </em>we measured dasometric, wood
 anatomical, and leaf traits (Table 1). (i)<strong>
 </strong>Three specific dasometric traits were measured in 20
 <em>Magnolia</em> individuals (DBH ≥ 50 cm). 1) Tree height
 (measured with Nikon Forestry PRO II Laser Rangefinder/Hypsometer); 2)
 diameter at breast high (DBH; measured at 1.3 m tree height with a
 diameter tape; Forestry Suppliers, Model 283D/20F) (Pretzsch 2009); and 3)
 bark thickness (measured with the Swedish bark gauge; SUUNTO, 60 mm,
 Vantaa, Finland). The bark thickness was taken from the cardinal positions
 (e.g., north, south, east, and west) around the stem (Wilms et al. 2021;
 https://doi.org/10.3390/ f12101386). (ii)<strong>
 </strong>We measured six wood anatomical traits (tree-ring width,
 hydraulic diameter, vulnerability index, fiber lumen diameter, fiber
 length, and fiber wall thickness). To obtain tree-ring width (TRW) data,
 we cored twice 20 <em>Magnolia</em> individuals at 1.5 m
 (breast height) with a borer of 5 mm internal diameter
 (Häglof<sup>®</sup>, Langsele, Sweden). The cores were dried
 at room temperature (48 h), glued to wooden supports, and polished with
 coarse (100, and 360 grit) and fine (400, 600, 800, 1000, 1200, 1500,
 2000, and 2500 grit) sandpaper for best visualization of annual growth
 rings and vessel structure in cross-section (Rodríguez-Ramírez et al.
 2023). Wood dust and vessel lumina were removed using a compressed air
 device. Wood core samples were preserved according to Speer (2010) and
 deposited at the Dendrochronology Lab, Universidad Continental, Huancayo,
 Peru. We measured the TRW using a stereoscopic microscope (OMAX®), and
 Velmex Tree Ring Measuring System (Velmex, Bloomfield, NY, USA) with an
 accuracy of 0.001 mm using TSAP-Win v.4.67c (Rinn 2003). The Southern
 Hemisphere Convention (Schulman, 1956) was used to assign the annual
 growth rings. On the other hand, to obtain hydraulic
 diameter (D<sub>H</sub>), vulnerability index
 (V<sub>I</sub>), fiber lumen diameter
 (F<sub>D</sub>), fiber length (F<sub>L</sub>), and
 fiber wall thickness (F<sub>WT</sub>) data, we collected stem
 discs from 10 <em>Magnolia</em> individuals containing bark
 and sapwood (~3 cm thick). The wood samples were obtained using a handsaw.
 Wood samples were immediately fixed in a formalin-acetic acid-ethanol
 solution (10:5:85) (McCracken and Johansen, 1940). After 48 h, the samples
 were washed with tap water and stored in a glycerin-ethanol-water solution
 (1:1:1; Sass, 1958) for 60 days. Microcore samples were paraffin-blocked,
 trimmed, and sectioned in a rotary microtome (8 μm thick). Sections were
 stained with safranin-fast green (Ruzin, 2000), mounted in synthetic
 resin, and then oven-dried in an oven at 60 °C for 24 h. Before staining,
 paraffin was removed using D-limonene, and the sections were rehydrated
 with alcohol solutions with decreasing concentration (van der Werf et al.
 2007). Additionally, we prepared macerations using Jeffrey's solution
 (Berlyn and Miksche, 1976) to collect data on vessel elements and fiber
 lengths. Wood microsections were prepared to obtain
 high-resolution anatomical images (1.3 µm per pixel resolution) following
 IAWA recommendations (IAWA Committee, 1989) and Piermattei et al. (2020).
 To obtain digital images mounted slides were observed under a light
 microscope (Olympus SZ61), associated with a digital camera (Leica DFC
 490), using the software ImagePro-Plus v. 4 (Media Cybernetics) was
 utilized to measure the vessel traits. We considered hydraulic diameter
 (D<sub>H</sub>, mm), vulnerability index
 (V<sub>I</sub>, 1 to &gt; 3), fiber lumen diameter
 (F<sub>D</sub>, mm), fiber length (F<sub>L</sub>,
 mm), and fiber wall thickness (F<sub>WT</sub>, mm) because
 these traits could provide an approximation of environmental
 susceptibility to how <em>Magnolia</em> wood is affected by
 climatic variation (Rodríguez-Ramírez et al. 2020, 2021).  
 (iii)<strong> </strong>We measured from 40 specimens
 four leaf vein traits related to ecohydraulic vulnerability. These
 included vein density (mm∙mm<sup>−2</sup>), vein length (cm),
 leaf base angle, and leaf shape (qualitative) (Rodríguez-Ramírez et al.
 2021). We digitalized 120 <em>Magnolia</em> leaves from
 herbarium collections (MO, MOL, USM, and HOXA herbarium. Each
 <em>Magnolia</em> specimen was placed directly on the glass of
 a high-resolution (700 dpi; accuracy 0.1 mm) flatbed scanner (HP OfficeJet
 Pro 7740, Hewlett-Packard Development Company, L.P., Houston, TX, USA).
 The measurements were performed using the software ImagePro-Plus v. 4
 (Media Cybernetics). <em>Climate data—
 </em>We used the monthly precipitation (Prec), evapotranspiration
 (EvT) in mm, mean maximum, and minimum temperature
 (T<sub>max</sub> and T<sub>min</sub>) in °C, from
 the CHELSA database (http://chelsa-climate.org/; Karger et al. 2021), the
 layer resolution was c. 1 km<sup>2</sup>, with records
 spanning from 1980 to 2018.<em> </em>
description: # Tracking climate vulnerability across spatial distribution and
 functional traits in *Magnolia gentryi* from the Peruvian tropical montane
 cloud forest ## Description of the Data and file structure We have
 attached the information on the database used and the analyses performed
 to obtain the results in the manuscript. Also attached are the statistical
 programs and software that users can use to obtain the information. 1\)
 Tree ring width measurement was performed using the free software COFECHA
 and the TSAP-Win v.4.67c 2\) Measurements of anatomical functional traits
 were performed with the aid of free access software ImageJ. 3\) Spatial
 analysis of *Magnolia gentryi* and climate data were achieved with the
 free access software SADIE v1.22, and the SURFER v. 26.1.216 4\) We
 performed statistical analyses using the software R. ## DATABASE CONTENTS
 The databases contain *Magnolia gentryi* chronology (chronology.csv),
 dasometric traits (Dasometric_assessments.txt), wood anatomical traits
 (Wood anatomical_assessments.txt), leaf vein traits (Leaf
 vein_assessments.text), climate data (Climatic_data.csv). A description of
 the included variables follows: * chronology.csv: Tree ring width
 information and year of formation. * column A in the database represents
 the years, and column B represents the ring width index data (mm). The
 rows mean the data. * Dasometric_assessments.txt: Dasometric metrics of
 *Magnolia gentryi*. * column A in the database represents Tree height (m),
 column B represents the DBH (cm), and column C represents Bark thickness
 (cm). * Wood anatomical_assessments.txt: Measurements of wood anatomical
 traits for the Andean Magnolia species studied (*Magnolia gentryi*): We
 considered hydraulic diameter (DH, mm), vulnerability index (VI, 1 to &gt;
 3), fiber lumen diameter (FD, mm), fiber length (FL, mm), and fiber wall
 thickness (FWT, mm) * column A, row 2 in the database represents hydraulic
 diameter, the column B, row 2 represents the vulnerability index, the
 column C, row 2 represents fiber lumen diameter, the column D, arrow 2
 represents the fiber length, and the column E represents fiber wall
 thickness * The rows 2-222 are represented by the wood anatomical trait
 measurements. * Leaf vein_assessments.text: Measurements of leaf vein
 traits for the *Magnolia gentryi*: We considered vein density (mm∙mm−2),
 vein length (cm), leaf base angle, and leaf shape (qualitative). * Column
 A, row 1 in the database represents vein length (cm); column B, row 1
 represents leaf base shape (0, 1, 2); column C, row 1 represents leaf
 shape (elliptic= 0, oblong= 1, elliptic-lanceolate= 2) and the column D,
 row 1 represents vein density (mm·mm−2). * The rows 2-41 are represented
 by the leaf vein trait measurements. * Climatic_data.cvs: We used the
 monthly precipitation (Prec), evapotranspiration (EvT) in mm, mean
 maximum, and minimum temperature (tmax and tmin) in °C, from the CHELSA
 database (Karger et al. 2021), and the layer resolution was c. 1 km2, with
 records spanning from 1980 to 2018. * Column A in the database represents
 the PREC in mm; column B represents EvT in mm; column C represents tmax in
 ºC; and column D represents tmin in ºC. ## Additional information COFECHA
 ([https://www.ltrr.arizona.edu/pub/dpl/A-INFO.HTM).-](https://www.ltrr.arizona.edu/pub/dpl/A-INFO.HTM\).-) Dating and measurement tree-ring quality control. TSAP-Win ([https://rinntech.info/products/tsap-win/).-](https://rinntech.info/products/tsap-win/\).-) Is used for analysis in dendrochronology, climate change, ecological patterns, growth and yield studies, and any application requiring accurate analysis of annual rings. ImageJ ([https://imagej.nih.gov/ij/download.html).-](https://imagej.nih.gov/ij/download.html\).-) The software is used to measure the characters of xylem vessels manually. SADIE ([https://repository.rothamsted.ac.uk/latest).-](https://repository.rothamsted.ac.uk/latest\).-) They outline the software to measure and test spatial patterns in data from a single species and for spatial association species vs climate data. SURFER ([www.goldensoftware.com).-](http://www.goldensoftware.com\).-) Surfer helps engineers and scientists interpret complex geospatial datasets and transform them into insightful and understandable publication-ready models R-software ([https://www.r-project.org/).-](https://www.r-project.org/\).-) The program is used to complete all statistical analyses performed in the manuscript.