Herbarium specimens, photographs, and field observations show Philadelphia area plants are responding to climate change

Abstract

Of the species studied, woody plants with short flowering duration are the best indicators of a warming climate. For monthly minimum temperatures, temperatures 1 or 2 mo prior to flowering are most significantly correlated with flowering time. Studies combining herbarium specimens, photographs, and field observations are an effective method for detecting the effects of climate change on flowering times.

Herbarium specimens show contrasting phenological responses to Himalayan climate

“…The effect sizes seen in annual average warming on phenology (−2.27 d/°C) and fall warming on phenology (2.54 d/°C) are similar to effect sizes seen in similar studies (10,48), although some studies have shown considerably greater effect sizes (11). Flowering time of Rhododendron spp.…”

“…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. By drawing together historical collections dispersed across many herbaria, we show that herbarium records have the ability to provide information beyond systematics, and further afield than eastern North America and Europe.…”

“…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.…”

Indian monsoons shape dispersal phenology of plants

“…Lal et al [23] have argued that date of onset of summer monsoon over India could become more variable in future owing to climate change. Under these conditions, it might be difficult for dispersal phenologies tied to monsoons to track an increasingly variable climate [24,25]. A recent study, for example, has shown that long-established phenologies can be disrupted by climate change [26].…”

Arctic Plants Produce Vastly Different Numbers of Flowers in Three Contrasting Years at Lake Hazen, Quttinirpaaq National Park, Ellesmere Island, Nunavut, Canada

“…The sites were visited every 3-4 days in all 3 years. In 2013, monitoring was qualitative and subjective, following an approach successfully used by Panchen et al (2012), wherein the date of first flower, peak flowering and finish of flowering of each population was recorded. After reviewing the 2013 results, the approach for subsequent years was changed to counting flowers to provide a more definitive date for start, peak and finish of flowering.…”