{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,1,27]],"date-time":"2026-01-27T22:16:15Z","timestamp":1769552175732,"version":"3.49.0"},"reference-count":54,"publisher":"MDPI AG","issue":"4","license":[{"start":{"date-parts":[[2021,2,20]],"date-time":"2021-02-20T00:00:00Z","timestamp":1613779200000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"DOI":"10.13039\/501100001871","name":"Funda\u00e7\u00e3o para a Ci\u00eancia e a Tecnologia","doi-asserted-by":"publisher","award":["PTDC\/AAG-MAA\/3699\/2014)"],"award-info":[{"award-number":["PTDC\/AAG-MAA\/3699\/2014)"]}],"id":[{"id":"10.13039\/501100001871","id-type":"DOI","asserted-by":"publisher"}]},{"name":"Forest Research Center","award":["UIDB\/00239\/2020"],"award-info":[{"award-number":["UIDB\/00239\/2020"]}]},{"name":"Portuguese E-Infrastructure for Information and Research on Biodiversity","award":["POCI-01-0145-FEDER-022127"],"award-info":[{"award-number":["POCI-01-0145-FEDER-022127"]}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Remote Sensing"],"abstract":"<jats:p>Monitoring vegetation is extremely relevant in the context of climate change, and digital repeat photography is a method that has gained momentum due to a low cost\u2013benefit ratio. This work aims to demonstrate the possibility of using digital cameras instead of field spectroradiometers (FS) to track understory vegetation phenology in Mediterranean cork oak woodlands. A commercial camera was used to take monthly photographs that were processed with the Phenopix package to extract green chromatic coordinates (GCC). GCC showed good agreement with the normalized difference vegetation index (NDVI) and normalized difference water index (NDWI) obtained with FS data. The herbaceous layer displayed a very good fit between GCC and NDVI (coefficient of determination, represented by r2 = 0.89). On the contrary, the GCC of shrubs (Cistus salviifolius and Ulex airensis) showed a better fit with NDWI (r2 = 0.78 and 0.55, respectively) than with NDVI (r2 = 0.60 and 0.30). Models show that grouping shrub species together improves the predictive results obtained with ulex but not with cistus. Concerning the relationship with climatic factors, all vegetation types showed a response to rainfall and temperature. Grasses and cistus showed similar responses to meteorological drivers, particularly mean maximum temperature (r = \u22120.66 and \u22120.63, respectively). The use of digital repeat photography to track vegetation phenology was found to be very suitable for understory vegetation with the exception of one shrub species. Thus, this method proves to have the potential to monitor a wide spectrum of understory vegetation at a much lower cost than FS.<\/jats:p>","DOI":"10.3390\/rs13040776","type":"journal-article","created":{"date-parts":[[2021,2,21]],"date-time":"2021-02-21T21:15:01Z","timestamp":1613942101000},"page":"776","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":8,"title":["Using Digital Photography to Track Understory Phenology in Mediterranean Cork Oak Woodlands"],"prefix":"10.3390","volume":"13","author":[{"given":"Catarina","family":"Jorge","sequence":"first","affiliation":[{"name":"Forest Research Centre, School of Agriculture, University of Lisbon, Tapada da Ajuda, 1349-017 Lisbon, Portugal"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-5201-9836","authenticated-orcid":false,"given":"Jo\u00e3o M. N.","family":"Silva","sequence":"additional","affiliation":[{"name":"Forest Research Centre, School of Agriculture, University of Lisbon, Tapada da Ajuda, 1349-017 Lisbon, Portugal"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-5101-227X","authenticated-orcid":false,"given":"Joana","family":"Boavida-Portugal","sequence":"additional","affiliation":[{"name":"Forest Research Centre, School of Agriculture, University of Lisbon, Tapada da Ajuda, 1349-017 Lisbon, Portugal"},{"name":"MARE\u2013Marine and Environmental Sciences Centre, Universidade de \u00c9vora, 7004-516 \u00c9vora, Portugal"}]},{"given":"Cristina","family":"Soares","sequence":"additional","affiliation":[{"name":"Forest Research Centre, School of Agriculture, University of Lisbon, Tapada da Ajuda, 1349-017 Lisbon, Portugal"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-9118-193X","authenticated-orcid":false,"given":"Sofia","family":"Cerasoli","sequence":"additional","affiliation":[{"name":"Forest Research Centre, School of Agriculture, University of Lisbon, Tapada da Ajuda, 1349-017 Lisbon, Portugal"}]}],"member":"1968","published-online":{"date-parts":[[2021,2,20]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"379","DOI":"10.1023\/A:1016125215496","article-title":"Phenology: Its Importance to the Global Change Community","volume":"54","author":"Menzel","year":"2002","journal-title":"Clim. 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