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Liang M, Qin X. Statistics and Analysis of Digital Information on Vascular Plant Specimens and the History of Plant Collecting in Guangzhou, China. PLANTS (BASEL, SWITZERLAND) 2023; 12:3325. [PMID: 37765488 PMCID: PMC10535665 DOI: 10.3390/plants12183325] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/02/2023] [Revised: 09/18/2023] [Accepted: 09/19/2023] [Indexed: 09/29/2023]
Abstract
This paper presents a comprehensive analysis of digitized specimen data and relevant literature to investigate the vascular plant diversity in Guangzhou City, China. Specimen data were collected from various sources, including the China Digital Herbarium (CVH), the National Specimen Resource Sharing Platform (NSII), Global Plants on JSTOR, and the Global Biodiversity Information Facility (GBIF). Following data standardization, the study identified 41,890 vascular plant specimens, encompassing 248 families, 1563 genera, and 4536 species, including subspecies and cultivated plants. Among them, the native plants of Guangzhou city accounted for 60.6% of the species. The temporal analysis identified three distinct peaks in specimen collection: 1916-1920, 1928-1936, and 1950-1964. Collection activities were primarily concentrated between the months of April and November. The distribution of collected specimens exhibited significant variation among different species, with families such as Fabaceae, Poaceae, and Myrtaceae having the highest number of specimens. Similarly, genera such as Eucalyptus, Ficus, and Citrus were well-represented. The most frequently collected species included Litchi chinensis, Eucalyptus robusta, and Cycas taiwaniana. Remarkably, 21 species had specimen counts exceeding 100. Unfortunately, approximately three-quarters of the species had fewer than 10 recorded specimens. Alarmingly, 1220 species were represented by only one specimen. Geographically, the majority of specimens originated from the former suburbs of Guangzhou, Conghua Delta Mountain, and Liuxi River areas, while other regions had limited representation. In terms of specimen collections, the Herbarium of South China Botanical Garden of the Chinese Academy of Sciences (IBSC) recorded the highest number of specimens (13,828 specimens), followed by the Tree Herbarium of South China Agricultural University (CANT; 3869 specimens) and the Herbarium of Sun Yat-sen University (SYS; 3654 specimens). The collection history in Guangzhou spans nearly 300 years and can be broadly divided into two distinct periods. The first period extends from the late 13th century to 1949, primarily encompassing the collection efforts of foreign visitors in Guangzhou, and represents the pioneering phase of plant taxonomy research in China. The second period, from 1949 to the present, is characterized by extensive investigations and collection activities conducted by local scholars, with a specific emphasis on native plant resources. By meticulously organizing and verifying information derived from historical documents and specimens, the paper effectively summarizes the plant collection and research history of Guangzhou, providing detailed profiles of the key collectors. These findings furnish reliable historical reference materials for the study of plant taxonomy and diversity in Guangzhou.
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Affiliation(s)
- Miaoting Liang
- College of Forestry and Landscape Architecture, South China Agricultural University, Guangzhou 510642, China
| | - Xinsheng Qin
- College of Forestry and Landscape Architecture, South China Agricultural University, Guangzhou 510642, China
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2
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Faidiga AS, Oliver MG, Budke JM, Kalisz S. Shifts in flowering phenology in response to spring temperatures in eastern Tennessee. AMERICAN JOURNAL OF BOTANY 2023; 110:e16203. [PMID: 37327370 DOI: 10.1002/ajb2.16203] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/15/2023] [Revised: 04/20/2023] [Accepted: 04/21/2023] [Indexed: 06/18/2023]
Abstract
PREMISE Plant phenological shifts are among the clearest indicators of the effects of climate change. In North America, numerous studies in the northeastern United States have demonstrated earlier spring flowering compared to historical records. However, few studies have examined phenological shifts in the southeastern United States, a highly biodiverse region of North America characterized by dramatic variations in abiotic conditions over small geographic areas. METHODS We examined 1000+ digitized herbarium records along with location-specific temperature data to analyze phenological shifts of 14 spring-flowering species in two adjacent ecoregions in eastern Tennessee. RESULTS Spring-flowering plant communities in the Blue Ridge and the Ridge and Valley ecoregions differed in their sensitivity to temperature; plants in the Ridge and Valley flower 0.73 days earlier/°C on average compared to 1.09 days/°C for plants in the Blue Ridge. Additionally, for the majority of species in both ecoregions, flowering is sensitive to spring temperature; i.e., in warmer years, most species flowered earlier. Despite this sensitivity, we did not find support for community-level shifts in flowering within eastern Tennessee in recent decades, likely because increases in annual temperature in the southeast are driven primarily by warming summer (rather than spring) temperatures. CONCLUSIONS These results highlight the importance of including ecoregion as a predictor in phenological models for capturing variation in sensitivity among populations and suggest that even small shifts in temperature can have dramatic effects on phenology in response to climate in the southeastern United States.
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Affiliation(s)
- Alexandra S Faidiga
- Department of Ecology and Evolutionary Biology, University of Tennessee, Knoxville, TN, 37996, USA
| | - Margaret G Oliver
- Department of Ecology and Evolutionary Biology, University of Tennessee, Knoxville, TN, 37996, USA
- University of Tennessee Herbarium (TENN), University of Tennessee, Knoxville, TN, 37996, USA
| | - Jessica M Budke
- Department of Ecology and Evolutionary Biology, University of Tennessee, Knoxville, TN, 37996, USA
- University of Tennessee Herbarium (TENN), University of Tennessee, Knoxville, TN, 37996, USA
| | - Susan Kalisz
- Department of Ecology and Evolutionary Biology, University of Tennessee, Knoxville, TN, 37996, USA
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3
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Belitz MW, Larsen EA, Shirey V, Li D, Guralnick RP. Phenological research based on natural history collections: practical guidelines and a Lepidopteran case study. Funct Ecol 2022. [DOI: 10.1111/1365-2435.14173] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Affiliation(s)
- Michael W. Belitz
- Florida Museum of Natural History University of Florida Gainesville FL USA
| | - Elise A. Larsen
- Department of Biology Georgetown University Washington DC USA
| | - Vaughn Shirey
- Department of Biology Georgetown University Washington DC USA
| | - Daijiang Li
- Department of Biological Sciences Louisiana State University Baton Rouge LA USA
- Center for Computation & Technology Louisiana State University Baton Rouge LA USA
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4
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Hussein BR, Malik OA, Ong WH, Slik JWF. Applications of computer vision and machine learning techniques for digitized herbarium specimens: A systematic literature review. ECOL INFORM 2022. [DOI: 10.1016/j.ecoinf.2022.101641] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
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5
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Love NLR, Bonnet P, Goëau H, Joly A, Mazer SJ. Machine Learning Undercounts Reproductive Organs on Herbarium Specimens but Accurately Derives Their Quantitative Phenological Status: A Case Study of Streptanthus tortuosus. PLANTS (BASEL, SWITZERLAND) 2021; 10:plants10112471. [PMID: 34834835 PMCID: PMC8623300 DOI: 10.3390/plants10112471] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/20/2021] [Revised: 11/10/2021] [Accepted: 11/12/2021] [Indexed: 06/13/2023]
Abstract
Machine learning (ML) can accelerate the extraction of phenological data from herbarium specimens; however, no studies have assessed whether ML-derived phenological data can be used reliably to evaluate ecological patterns. In this study, 709 herbarium specimens representing a widespread annual herb, Streptanthus tortuosus, were scored both manually by human observers and by a mask R-CNN object detection model to (1) evaluate the concordance between ML and manually-derived phenological data and (2) determine whether ML-derived data can be used to reliably assess phenological patterns. The ML model generally underestimated the number of reproductive structures present on each specimen; however, when these counts were used to provide a quantitative estimate of the phenological stage of plants on a given sheet (i.e., the phenological index or PI), the ML and manually-derived PI's were highly concordant. Moreover, herbarium specimen age had no effect on the estimated PI of a given sheet. Finally, including ML-derived PIs as predictor variables in phenological models produced estimates of the phenological sensitivity of this species to climate, temporal shifts in flowering time, and the rate of phenological progression that are indistinguishable from those produced by models based on data provided by human observers. This study demonstrates that phenological data extracted using machine learning can be used reliably to estimate the phenological stage of herbarium specimens and to detect phenological patterns.
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Affiliation(s)
- Natalie L. R. Love
- Department of Ecology, Evolution, and Marine Biology, University of California, Santa Barbara, CA 93106, USA;
- Biological Sciences Department, California Polytechnic State University, San Luis Obispo, CA 93407, USA
| | - Pierre Bonnet
- Botany and Modeling of Plant Architecture and Vegetation (AMAP), French Agricultural Research Centre for International Development (CIRAD), French National Centre for Scientific Research (CNRS), French National Institute for Agriculture, Food and Environment (INRAE), Research Institute for Development (IRD), University of Montpellier, 34398 Montpellier, France; (P.B.); (H.G.)
| | - Hervé Goëau
- Botany and Modeling of Plant Architecture and Vegetation (AMAP), French Agricultural Research Centre for International Development (CIRAD), French National Centre for Scientific Research (CNRS), French National Institute for Agriculture, Food and Environment (INRAE), Research Institute for Development (IRD), University of Montpellier, 34398 Montpellier, France; (P.B.); (H.G.)
| | - Alexis Joly
- ZENITH Team, Laboratory of Informatics, Robotics and Microelectronics-Joint Research Unit, Institut National de Recherche en Informatique et en Automatique (INRIA) Sophia-Antipolis, CEDEX 5, 34095 Montpellier, France;
| | - Susan J. Mazer
- Department of Ecology, Evolution, and Marine Biology, University of California, Santa Barbara, CA 93106, USA;
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Kalvāne G, Kalvāns A. Phenological trends of multi-taxonomic groups in Latvia, 1970-2018. INTERNATIONAL JOURNAL OF BIOMETEOROLOGY 2021; 65:895-904. [PMID: 33427945 DOI: 10.1007/s00484-020-02068-8] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/25/2020] [Accepted: 12/14/2020] [Indexed: 06/12/2023]
Abstract
Phenology provides intimate insights into ongoing changes in nature and seasonality with respect to humans. In this study, the most complete volunteer observer phenological data set for the territory of Latvia from 1970 to 2018 was evaluated. The data set includes observations of 159 phases of eight taxonomical groups, as well as abiotic phenomena such as the first snow, last spring frost, and agrarian activities. With reducing dimensionality, a hierarchical cluster analysis was used to group the 66 phenological phases of most observations into 7 clusters. The largest changes were observed in the early spring phenological phases of the pioneer species such as the start of flowering of Corylus avellana (hazel), Alnus incana (grey alder) and Populus tremula (aspen), noted as -8 days/decade. The trend of the spring emergence of insects and spring migratory birds also showed a negative tendency. The phenology of crops and agrarian activities has not changed significantly. The trends of the autumn phases were heterogeneous-leaf colouration and fall for some species (Populus tremula) and (Acer platanoides, Norway maple) was recorded on average later; for other species, there was a slightly earlier trend (Betula pendula, silver birch; Tilia cordata, linden). Earlier onset of the spring phases affects the changes in the length of the growing season (for Acer platanoides + 7.7 days/decade; Betula pendula + 3.3 days/decade). Since 1990, it has been common that many phases have begun sooner (particularly spring phases), whilst abiotic autumn phases have been characterised by late years. This study has shown that significant seasonal changes have taken place across the Latvian landscape due to climate change.
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Affiliation(s)
- Gunta Kalvāne
- Faculty of Geography and Earth Sciences, University of Latvia, Riga, Latvia.
| | - Andis Kalvāns
- Faculty of Geography and Earth Sciences, University of Latvia, Riga, Latvia
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Estimating and Monitoring Land Surface Phenology in Rangelands: A Review of Progress and Challenges. REMOTE SENSING 2021. [DOI: 10.3390/rs13112060] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Land surface phenology (LSP) has been extensively explored from global archives of satellite observations to track and monitor the seasonality of rangeland ecosystems in response to climate change. Long term monitoring of LSP provides large potential for the evaluation of interactions and feedbacks between climate and vegetation. With a special focus on the rangeland ecosystems, the paper reviews the progress, challenges and emerging opportunities in LSP while identifying possible gaps that could be explored in future. Specifically, the paper traces the evolution of satellite sensors and interrogates their properties as well as the associated indices and algorithms in estimating and monitoring LSP in productive rangelands. Findings from the literature revealed that the spectral characteristics of the early satellite sensors such as Landsat, AVHRR and MODIS played a critical role in the development of spectral vegetation indices that have been widely used in LSP applications. The normalized difference vegetation index (NDVI) pioneered LSP investigations, and most other spectral vegetation indices were primarily developed to address the weaknesses and shortcomings of the NDVI. New indices continue to be developed based on recent sensors such as Sentinel-2 that are characterized by unique spectral signatures and fine spatial resolutions, and their successful usage is catalyzed with the development of cutting-edge algorithms for modeling the LSP profiles. In this regard, the paper has documented several LSP algorithms that are designed to provide data smoothing, gap filling and LSP metrics retrieval methods in a single environment. In the future, the development of machine learning algorithms that can effectively model and characterize the phenological cycles of vegetation would help to unlock the value of LSP information in the rangeland monitoring and management process. Precisely, deep learning presents an opportunity to further develop robust software packages such as the decomposition and analysis of time series (DATimeS) with the abundance of data processing tools and techniques that can be used to better characterize the phenological cycles of vegetation in rangeland ecosystems.
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Davis CC, Champ J, Park DS, Breckheimer I, Lyra GM, Xie J, Joly A, Tarapore D, Ellison AM, Bonnet P. A New Method for Counting Reproductive Structures in Digitized Herbarium Specimens Using Mask R-CNN. FRONTIERS IN PLANT SCIENCE 2020; 11:1129. [PMID: 32849691 PMCID: PMC7411132 DOI: 10.3389/fpls.2020.01129] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/12/2020] [Accepted: 07/09/2020] [Indexed: 05/29/2023]
Abstract
Phenology-the timing of life-history events-is a key trait for understanding responses of organisms to climate. The digitization and online mobilization of herbarium specimens is rapidly advancing our understanding of plant phenological response to climate and climatic change. The current practice of manually harvesting data from individual specimens, however, greatly restricts our ability to scale-up data collection. Recent investigations have demonstrated that machine-learning approaches can facilitate this effort. However, present attempts have focused largely on simplistic binary coding of reproductive phenology (e.g., presence/absence of flowers). Here, we use crowd-sourced phenological data of buds, flowers, and fruits from >3,000 specimens of six common wildflower species of the eastern United States (Anemone canadensis L., A. hepatica L., A. quinquefolia L., Trillium erectum L., T. grandiflorum (Michx.) Salisb., and T. undulatum Wild.) to train models using Mask R-CNN to segment and count phenological features. A single global model was able to automate the binary coding of each of the three reproductive stages with >87% accuracy. We also successfully estimated the relative abundance of each reproductive structure on a specimen with ≥90% accuracy. Precise counting of features was also successful, but accuracy varied with phenological stage and taxon. Specifically, counting flowers was significantly less accurate than buds or fruits likely due to their morphological variability on pressed specimens. Moreover, our Mask R-CNN model provided more reliable data than non-expert crowd-sourcers but not botanical experts, highlighting the importance of high-quality human training data. Finally, we also demonstrated the transferability of our model to automated phenophase detection and counting of the three Trillium species, which have large and conspicuously-shaped reproductive organs. These results highlight the promise of our two-phase crowd-sourcing and machine-learning pipeline to segment and count reproductive features of herbarium specimens, thus providing high-quality data with which to investigate plant responses to ongoing climatic change.
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Affiliation(s)
- Charles C. Davis
- Department of Organismic and Evolutionary Biology, Harvard University Herbaria, Harvard University, Cambridge, MA, United States
| | - Julien Champ
- LIRMM, Inria, University of Montpellier, Montpellier, France
| | - Daniel S. Park
- Department of Organismic and Evolutionary Biology, Harvard University Herbaria, Harvard University, Cambridge, MA, United States
| | - Ian Breckheimer
- Department of Organismic and Evolutionary Biology, Harvard University Herbaria, Harvard University, Cambridge, MA, United States
| | - Goia M. Lyra
- Department of Organismic and Evolutionary Biology, Harvard University Herbaria, Harvard University, Cambridge, MA, United States
- Universidade Federal da Bahia (UFBA), Salvador, Brazil
| | - Junxi Xie
- Department of Organismic and Evolutionary Biology, Harvard University Herbaria, Harvard University, Cambridge, MA, United States
| | - Alexis Joly
- LIRMM, Inria, University of Montpellier, Montpellier, France
| | - Dharmesh Tarapore
- Department of Computer Science, Boston University, Boston, MA, United States
| | - Aaron M. Ellison
- Harvard Forest, Harvard University, Petersham, MA, United States
| | - Pierre Bonnet
- CIRAD, UMR AMAP, Montpellier, France
- AMAP, Univ Montpellier, CIRAD, CNRS, INRAE, IRD, Montpellier, France
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9
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Goëau H, Mora‐Fallas A, Champ J, Love NLR, Mazer SJ, Mata‐Montero E, Joly A, Bonnet P. A new fine-grained method for automated visual analysis of herbarium specimens: A case study for phenological data extraction. APPLICATIONS IN PLANT SCIENCES 2020; 8:e11368. [PMID: 32626610 PMCID: PMC7328656 DOI: 10.1002/aps3.11368] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/04/2019] [Accepted: 02/02/2020] [Indexed: 05/26/2023]
Abstract
PREMISE Herbarium specimens represent an outstanding source of material with which to study plant phenological changes in response to climate change. The fine-scale phenological annotation of such specimens is nevertheless highly time consuming and requires substantial human investment and expertise, which are difficult to rapidly mobilize. METHODS We trained and evaluated new deep learning models to automate the detection, segmentation, and classification of four reproductive structures of Streptanthus tortuosus (flower buds, flowers, immature fruits, and mature fruits). We used a training data set of 21 digitized herbarium sheets for which the position and outlines of 1036 reproductive structures were annotated manually. We adjusted the hyperparameters of a mask R-CNN (regional convolutional neural network) to this specific task and evaluated the resulting trained models for their ability to count reproductive structures and estimate their size. RESULTS The main outcome of our study is that the performance of detection and segmentation can vary significantly with: (i) the type of annotations used for training, (ii) the type of reproductive structures, and (iii) the size of the reproductive structures. In the case of Streptanthus tortuosus, the method can provide quite accurate estimates (77.9% of cases) of the number of reproductive structures, which is better estimated for flowers than for immature fruits and buds. The size estimation results are also encouraging, showing a difference of only a few millimeters between the predicted and actual sizes of buds and flowers. DISCUSSION This method has great potential for automating the analysis of reproductive structures in high-resolution images of herbarium sheets. Deeper investigations regarding the taxonomic scalability of this approach and its potential improvement will be conducted in future work.
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Affiliation(s)
- Hervé Goëau
- AMAPUniversity of MontpellierCIRADCNRSINRAEIRDMontpellierFrance
- CIRADUMR AMAPMontpellierFrance
| | - Adán Mora‐Fallas
- School of ComputingCosta Rica Institute of TechnologyCartagoCosta Rica
| | - Julien Champ
- Institut national de recherche en informatique et en automatique (INRIA) Sophia‐Antipolis, ZENITH teamLaboratory of InformaticsRobotics and Microelectronics–Joint Research Unit, 34095MontpellierCEDEX 5France
| | - Natalie L. Rossington Love
- Department of Ecology, Evolution, and Marine BiologyUniversity of California, Santa BarbaraSanta BarbaraCalifornia93106USA
| | - Susan J. Mazer
- Department of Ecology, Evolution, and Marine BiologyUniversity of California, Santa BarbaraSanta BarbaraCalifornia93106USA
| | | | - Alexis Joly
- Institut national de recherche en informatique et en automatique (INRIA) Sophia‐Antipolis, ZENITH teamLaboratory of InformaticsRobotics and Microelectronics–Joint Research Unit, 34095MontpellierCEDEX 5France
| | - Pierre Bonnet
- AMAPUniversity of MontpellierCIRADCNRSINRAEIRDMontpellierFrance
- CIRADUMR AMAPMontpellierFrance
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McDonough MacKenzie C, Gallinat AS, Zipf L. Low-cost observations and experiments return a high value in plant phenology research. APPLICATIONS IN PLANT SCIENCES 2020; 8:e11338. [PMID: 32351799 PMCID: PMC7186900 DOI: 10.1002/aps3.11338] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/01/2019] [Accepted: 12/03/2019] [Indexed: 05/18/2023]
Abstract
Plant ecologists in the Anthropocene are tasked with documenting, interpreting, and predicting how plants respond to environmental change. Phenology, the timing of seasonal biological events including leaf-out, flowering, fruiting, and leaf senescence, is among the most visible and oft-recorded facets of plant ecology. Climate-driven shifts in plant phenology can alter reproductive success, interspecific competition, and trophic interactions. Low-cost phenology research, including observational records and experimental manipulations, is fundamental to our understanding of both the mechanisms and effects of phenological change in plant populations, species, and communities. Traditions of local-scale botanical phenology observations and data leveraged from written records and natural history collections provide the historical context for recent observations of changing phenologies. New technology facilitates expanding the spatial, taxonomic, and human interest in this research by combining contemporary field observations by researchers and open access community science (e.g., USA National Phenology Network) and available climate data. Established experimental techniques, such as twig cutting and common garden experiments, are low-cost methods for studying the mechanisms and drivers of plant phenology, enabling researchers to observe phenological responses under novel environmental conditions. We discuss the strengths, limitations, potential hidden costs (i.e., volunteer and student labor), and promise of each of these methods for addressing emerging questions in plant phenology research. Applied thoughtfully, economically, and creatively, many low-cost approaches offer novel opportunities to fill gaps in our geographic, taxonomic, and mechanistic understanding of plant phenology worldwide.
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Affiliation(s)
| | - Amanda S. Gallinat
- Department of BiologyUtah State UniversityLoganUtah84322USA
- Ecology CenterUtah State UniversityLoganUtah84322USA
| | - Lucy Zipf
- Biology DepartmentBoston University5 Cummington MallBostonMassachusetts02215USA
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11
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Love NLR, Park IW, Mazer SJ. A new phenological metric for use in pheno-climatic models: A case study using herbarium specimens of Streptanthus tortuosus. APPLICATIONS IN PLANT SCIENCES 2019; 7:e11276. [PMID: 31346508 PMCID: PMC6636619 DOI: 10.1002/aps3.11276] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/07/2019] [Accepted: 05/17/2019] [Indexed: 05/13/2023]
Abstract
PREMISE Herbarium specimens have been used to detect climate-induced shifts in flowering time by using the day of year of collection (DOY) as a proxy for first or peak flowering date. Variation among herbarium sheets in their phenological status, however, undermines the assumption that DOY accurately represents any particular phenophase. Ignoring this variation can reduce the explanatory power of pheno-climatic models (PCMs) designed to predict the effects of climate on flowering date. METHODS Here we present a protocol for the phenological scoring of imaged herbarium specimens using an ImageJ plugin, and we introduce a quantitative metric of a specimen's phenological status, the phenological index (PI), which we use in PCMs to control for phenological variation among specimens of Streptanthus tortuosus (Brassicaceeae) when testing for the effects of climate on DOY. We demonstrate that including PI as an independent variable improves model fit. RESULTS Including PI in PCMs increased the model R 2 relative to PCMs that excluded PI; regression coefficients for climatic parameters, however, remained constant. DISCUSSION Our protocol provides a simple, quantitative phenological metric for any observed plant. Including PI in PCMs increases R 2 and enables predictions of the DOY of any phenophase under any specified climatic conditions.
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Affiliation(s)
- Natalie L. Rossington Love
- Department of Ecology, Evolution, and Marine BiologyUniversity of California, Santa BarbaraSanta BarbaraCalifornia93106USA
| | - Isaac W. Park
- Department of Ecology, Evolution, and Marine BiologyUniversity of California, Santa BarbaraSanta BarbaraCalifornia93106USA
| | - Susan J. Mazer
- Department of Ecology, Evolution, and Marine BiologyUniversity of California, Santa BarbaraSanta BarbaraCalifornia93106USA
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12
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Pearson KD. Spring- and fall-flowering species show diverging phenological responses to climate in the Southeast USA. INTERNATIONAL JOURNAL OF BIOMETEOROLOGY 2019; 63:481-492. [PMID: 30734127 DOI: 10.1007/s00484-019-01679-0] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/25/2018] [Revised: 01/09/2019] [Accepted: 01/19/2019] [Indexed: 06/09/2023]
Abstract
Plant phenological shifts (e.g., earlier flowering dates) are known consequences of climate change that may alter ecosystem functioning, productivity, and ecological interactions across trophic levels. Temperate, subalpine, and alpine regions have largely experienced advancement of spring phenology with climate warming, but the effects of climate change in warm, humid regions and on autumn phenology are less well understood. In this study, nearly 10,000 digitized herbarium specimen records were used to examine the phenological sensitivities of fall- and spring-flowering asteraceous plants to temperature and precipitation in the US Southeastern Coastal Plain. Climate data reveal warming trends in this already warm climate, and spring- and fall-flowering species responded differently to this change. Spring-flowering species flowered earlier at a rate of 1.8-2.3 days per 1 °C increase in spring temperature, showing remarkable congruence with studies of northern temperate species. Fall-flowering species flowered slightly earlier with warmer spring temperatures, but flowering was significantly later with warmer summer temperatures at a rate of 0.8-1.2 days per 1 °C. Spring-flowering species exhibited slightly later flowering times with increased spring precipitation. Fall phenology was less clearly influenced by precipitation. These results suggest that even warm, humid regions may experience phenological shifts and thus be susceptible to potentially detrimental effects such as plant-pollinator asynchrony.
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Affiliation(s)
- Katelin D Pearson
- Department of Biological Sciences, Florida State University, 319 Stadium Dr, Tallahassee, FL, USA.
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13
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Ellwood ER, Pearson KD, Nelson G. Emerging frontiers in phenological research. APPLICATIONS IN PLANT SCIENCES 2019; 7:e01234. [PMCID: PMC6426156 DOI: 10.1002/aps3.1234] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/28/2019] [Accepted: 03/01/2019] [Indexed: 06/10/2023]
Affiliation(s)
| | - Katelin D. Pearson
- California Polytechnic University1 Grand AvenueSan Luis ObispoCalifornia93405USA
| | - Gil Nelson
- iDigBioFlorida Museum of Natural HistoryGainesvilleFlorida32611USA
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14
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Lorieul T, Pearson KD, Ellwood ER, Goëau H, Molino J, Sweeney PW, Yost JM, Sachs J, Mata‐Montero E, Nelson G, Soltis PS, Bonnet P, Joly A. Toward a large-scale and deep phenological stage annotation of herbarium specimens: Case studies from temperate, tropical, and equatorial floras. APPLICATIONS IN PLANT SCIENCES 2019; 7:e01233. [PMID: 30937225 PMCID: PMC6426157 DOI: 10.1002/aps3.1233] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/07/2018] [Accepted: 01/28/2019] [Indexed: 05/20/2023]
Abstract
PREMISE OF THE STUDY Phenological annotation models computed on large-scale herbarium data sets were developed and tested in this study. METHODS Herbarium specimens represent a significant resource with which to study plant phenology. Nevertheless, phenological annotation of herbarium specimens is time-consuming, requires substantial human investment, and is difficult to mobilize at large taxonomic scales. We created and evaluated new methods based on deep learning techniques to automate annotation of phenological stages and tested these methods on four herbarium data sets representing temperate, tropical, and equatorial American floras. RESULTS Deep learning allowed correct detection of fertile material with an accuracy of 96.3%. Accuracy was slightly decreased for finer-scale information (84.3% for flower and 80.5% for fruit detection). DISCUSSION The method described has the potential to allow fine-grained phenological annotation of herbarium specimens at large ecological scales. Deeper investigation regarding the taxonomic scalability of this approach is needed.
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Affiliation(s)
- Titouan Lorieul
- University of MontpellierMontpellierCEDEX 5France
- Institut national de recherche en informatique et en automatique (INRIA) Sophia‐Antipolis, ZENITH team, Laboratory of InformaticsRobotics and Microelectronics–Joint Research Unit, 34095MontpellierCEDEX 5France
| | - Katelin D. Pearson
- Department of Biological ScienceFlorida State University319 Stadium DriveTallahasseeFlorida32306USA
| | - Elizabeth R. Ellwood
- La Brea Tar Pits and MuseumNatural History Museum of Los Angeles County5801 Wilshire BoulevardLos AngelesCalifornia90036USA
| | - Hervé Goëau
- AMAPUniversité de MontpellierCIRAD, CNRS, INRA, IRDMontpellierFrance
- CIRAD, UMR AMAPMontpellierFrance
| | | | - Patrick W. Sweeney
- Division of BotanyPeabody Museum of Natural HistoryYale UniversityP.O. Box 208118New HavenConnecticut06520USA
| | - Jennifer M. Yost
- Department of Biological SciencesCalifornia Polytechnic State University1 Grand AvenueSan Luis ObispoCalifornia93407USA
| | - Joel Sachs
- Agriculture and Agri‐Food CanadaOttawaCanada
| | | | - Gil Nelson
- iDigBioFlorida State UniversityTallahasseeFlorida32306USA
| | - Pamela S. Soltis
- Florida Museum of Natural HistoryUniversity of FloridaGainesvilleFlorida32611USA
| | - Pierre Bonnet
- AMAPUniversité de MontpellierCIRAD, CNRS, INRA, IRDMontpellierFrance
- CIRAD, UMR AMAPMontpellierFrance
| | - Alexis Joly
- Institut national de recherche en informatique et en automatique (INRIA) Sophia‐Antipolis, ZENITH team, Laboratory of InformaticsRobotics and Microelectronics–Joint Research Unit, 34095MontpellierCEDEX 5France
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Richardson AD, Hufkens K, Li X, Ault TR. Testing Hopkins' Bioclimatic Law with PhenoCam data. APPLICATIONS IN PLANT SCIENCES 2019; 7:e01228. [PMID: 30937220 PMCID: PMC6426166 DOI: 10.1002/aps3.1228] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/01/2018] [Accepted: 12/03/2018] [Indexed: 05/23/2023]
Abstract
PREMISE OF THE STUDY We investigated the spatial and temporal patterns of vegetation phenology with phenometrics derived from PhenoCam imagery. Specifically, we evaluated the Bioclimatic Law proposed by Hopkins, which relates phenological transitions to latitude, longitude, and elevation. METHODS "Green-up" and "green-down" dates-representing the start and end of the annual cycles of vegetation activity-were estimated from measures of canopy greenness calculated from digital repeat photography. We used data from 65 deciduous broadleaf (DB) forest sites, 18 evergreen needleleaf (EN) forest sites, and 21 grassland (GR) sites. RESULTS DB green-up dates were well correlated with mean annual temperature and varied along spatial gradients consistent with the Bioclimatic Law. Interannual variation in DB phenology was most strongly associated with temperature anomalies during a relatively narrow window of time. EN phenology was not well correlated with either climatic factors or spatial gradients, but similar to DB phenology, interannual variation was most closely associated with temperature anomalies. For GR sites, mean annual precipitation explained most of the spatial variation in the duration of vegetation activity, whereas both temperature and precipitation anomalies explained interannual variation in phenology. DISCUSSION PhenoCam data provide an objective and consistent means by which spatial and temporal patterns in vegetation phenology can be investigated.
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Affiliation(s)
- Andrew D. Richardson
- School of Informatics, Computing, and Cyber SystemsNorthern Arizona UniversityFlagstaffArizona86011USA
- Center for Ecosystem Science and SocietyNorthern Arizona UniversityFlagstaffArizona86011USA
| | - Koen Hufkens
- Department of Applied Ecology and Environmental BiologyGhent UniversityGhentBelgium
- INRAUMR ISPAVillenave d'OrnonFrance
| | - Xiaolu Li
- Department of Earth and Atmospheric SciencesCornell UniversityIthacaNew York14853USA
| | - Toby R. Ault
- Department of Earth and Atmospheric SciencesCornell UniversityIthacaNew York14853USA
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Ellwood ER, Primack RB, Willis CG, HilleRisLambers J. Phenology models using herbarium specimens are only slightly improved by using finer-scale stages of reproduction. APPLICATIONS IN PLANT SCIENCES 2019; 7:e01225. [PMID: 30937218 PMCID: PMC6426165 DOI: 10.1002/aps3.1225] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/01/2018] [Accepted: 11/02/2018] [Indexed: 05/22/2023]
Abstract
PREMISE OF THE STUDY Herbarium specimens are increasingly used to study reproductive phenology. Here, we ask whether classifying reproduction into progressively finer-scale stages improves our understanding of the relationship between climate and reproductive phenology. METHODS We evaluated Acer rubrum herbarium specimens across eastern North America, classifying them into eight reproductive phenophases and four stages of leaf development. We fit models with different reproductive phenology categorization schemes (from detailed to broad) and compared model fits and coefficients describing temperature, elevation, and year effects. We fit similar models to leaf phenology data to compare reproductive to leafing phenology. RESULTS Finer-scale reproductive phenophases improved model fits and provided more precise estimates of reproductive phenology. However, models with fewer reproductive phenophases led to similar qualitative conclusions, demonstrating that A. rubrum reproduces earlier in warmer locations, lower elevations, and in recent years, as well as that leafing phenology is less strongly influenced by temperature than is reproductive phenology. DISCUSSION Our study suggests that detailed information on reproductive phenology provides a fuller understanding of potential climate change effects on flowering, fruiting, and leaf-out. However, classification schemes with fewer reproductive phenophases provided many similar insights and may be preferable in cases where resources are limited.
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Affiliation(s)
- Elizabeth R. Ellwood
- La Brea Tar Pits and MuseumNatural History Museum of Los Angeles County5801 Wilshire BoulevardLos AngelesCalifornia90036USA
| | - Richard B. Primack
- Biology DepartmentBoston University5 Cummington MallBostonMassachusetts02215USA
| | - Charles G. Willis
- Department of Organismic and Evolutionary Biology and Harvard University HerbariaHarvard UniversityCambridgeMassachusetts02138USA
- Department of Biology Teaching and LearningUniversity of MinnesotaMinneapolisMinnesota55455USA
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Panchen ZA, Doubt J, Kharouba HM, Johnston MO. Patterns and biases in an Arctic herbarium specimen collection: Implications for phenological research. APPLICATIONS IN PLANT SCIENCES 2019; 7:e01229. [PMID: 30937221 PMCID: PMC6426279 DOI: 10.1002/aps3.1229] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/22/2018] [Accepted: 11/16/2018] [Indexed: 06/01/2023]
Abstract
PREMISE OF THE STUDY Herbarium specimens are increasingly used in phenological studies. However, natural history collections can have biases that influence the analysis of phenological events. Arctic environments, where remoteness and cold climate govern collection logistics, may give rise to unique or pronounced biases. METHODS We assessed the presence of biases in time, space, phenological events, collectors, taxonomy, and plant traits across Nunavut using herbarium specimens accessioned at the National Herbarium of Canada (CAN). RESULTS We found periods of high and low collection that corresponded to societal and institutional events; greater collection density close to common points of air and sea access; and preferences to collect plants at the flowering phase and in peak flower, and to collect particular taxa, flower colours, growth forms, and plant heights. One-quarter of collectors contributed 90% of the collection. DISCUSSION Collections influenced by temporal and spatial biases have the potential to misrepresent phenology across space and time, whereas those shaped by the interests of collectors or the tendency to favour particular phenological stages, taxa, and plant traits could give rise to imbalanced phenological comparisons. Underlying collection patterns may vary among regions and institutions. To guide phenological analyses, we recommend routine assessment of any herbarium data set prior to its use.
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Affiliation(s)
- Zoe A. Panchen
- Department of GeographyUniversity of British ColumbiaVancouverBritish ColumbiaCanada
| | - Jennifer Doubt
- Centre for Arctic Knowledge and ExplorationCanadian Museum of NatureOttawaOntarioCanada
| | | | - Mark O. Johnston
- Department of BiologyDalhousie UniversityHalifaxNova ScotiaCanada
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