Validation of biological collections as a source of phenological data for use in climate change studies: a case study with the orchid Ophrys sphegodes

Abstract

Summary1. The scarcity of reliable long-term phenological data has severely hindered the study of the responses of species to climate change. Biological collections in herbaria and museums are potential sources of long-term data for such study, but their use for this purpose needs independent validation. Here we report a rigorous test of the validity of using herbarium specimens for phenological studies, by comparing relationships between climate and time of peak flowering derived from herbarium records and from direct field-based observations, for the terrestrial orchid Ophrys sphegodes. 2. We examined herbarium specimens of O. sphegodes collected between 1848 and 1958, and recorded peak flowering time directly in one population of O. sphegodes between 1975 and 2006. The response of flowering time to variation in mean spring temperature (March-May) was virtually identical in both sets of data, even though they covered different periods of time which differ in extent of anthropogenic temperature change. In both cases flowering was advanced by c. 6 days per°C rise in average spring temperature. 3. The proportion of variation in flowering time explained by spring temperature was lower in the herbarium record than in direct field observations. It is likely that some of the additional variation was due to geographical variation in collection site, as flowering was significantly earlier at more westerly sites, which have had warmer springs, over their range of 3.44°of longitude. 4. Predictions of peak flowering time based on the herbarium data corresponded closely with observed peak flowering times in the field, indicating that flowering response to temperature had not altered between the two separate periods over which the herbarium and field data were collected. 5. Synthesis. These results provide the first direct validation of the use of herbarium collections to examine the relationships between phenology and climate when field-based observational data are not available.

Herbarium specimens show contrasting phenological responses to Himalayan climate

“…Although phenological analyses of herbarium data offer unique insights into past responses, they model past responses only, and long-term phenological observation is necessary to fully understand present responses and model those in the future. To complement the herbarium data and test our models, we are directly monitoring Rhododendron phenology on Yulong Mountain, conducting artificial warming experiments, and documenting indigenous peoples' observations of change.This study joins other work from the past decade showing the value of herbarium collections to infer long-term phenology (10,11,43,48,(51)(52)(53)(54)(55)(56)(57)(58)(59)(60)(61)(62)(63). These have increasingly shown that not only can the "messy" data from herbarium collections be used to infer phenology, but that these data can reveal the complex effects on phenology of geography (43), pollination (62), morphological traits (48, 52), and, in this study, the contrasting response of warming across different seasons.…”

“…In addition, our analysis of specimens for which at least month of collection was available yielded similar results to those for which day of collection was available. This suggests that even "incomplete" data such as these, which are often discarded from analysis (11,54,56), may merit examination.Finally, a decline in botanical collection in recent years noted by other authors (10, 54) is also reflected in our data (Fig. S1).…”

“…Changes in phenology potentially impact organism reproduction, population survival, species boundaries, and ecosystem service (6)(7)(8). However, despite the importance of phenological changes (9,10), data sources are limited (11). Satellite imagery (12), experimental studies (13), and modern observational records of phenology (11,14) are temporally restricted to the last few decades.…”

“…However, despite the importance of phenological changes (9,10), data sources are limited (11). Satellite imagery (12), experimental studies (13), and modern observational records of phenology (11,14) are temporally restricted to the last few decades. Although historical phenological records kept by scientists, amateur naturalists, or for cultural reasons (15)(16)(17) may extend much further, these are often limited in geographic range, and tend to focus on North America and Europe (but see ref.…”

Potential distribution and geographic characteristics of wild populations of Vanilla planifolia (Orchidaceae) Oaxaca, Mexico

“…Los hábitats de plantas silvestres, como las orquídeas, han sido afectadas negativamente por la interferencia humana y el cambio climático (Robbirt, Davy, Hutchings, & Roberts, 2011;Sánchez, Osborne, & Haq, 2011). Para evaluar estos efectos, los modelos de distribución de especies son una herramienta útil (Guisan & Zimmermann, 2000;De Marco Junior & Siqueira, 2009;Siqueira & Durigan, 2007), ya que permiten identificar áreas potenciales donde puede desarrollarse la especie, y predecir cambios en las zonas de distribución (Rezende, Oliveira-Filho, Eisenlohr, Kamino, & Vibrans, 2014).…”