Question

Phenology Climate Shifts and ecological consequences. What evidence do we have that plant flowering dates are changing? What is the problem with changes is phenology? Does there seem to be a link with changing or not changing and species decline? Are all groups of plants affected equally? Around Concord, MA what other factors may be confounding influences on local plant diversity?  

Answer 1

Temperature and photoperiod are widely accepted as the proximal abiotic stimuli for phenological changes in plants. Plant phenology is sensitive to climate change; the timing of flowering has served as a visible indicator of plant phenology.  A number of studies have revealed that for most species the onset of spring phenological events has advanced to earlier in the season over the past decades as plants respond to global warming. some species have exhibited little change in the timing of flowering or flowering has occurred even later in other species. Early-flowering species reacted more strongly and sensitively to climate change than late-flowering species. Plants with different pollination types and different phylogenetic relationships use a variety of mechanisms to adapt to climate change. Even duration of flowering was compressed by a sudden rainfall event after a long period of drought. Periods of extreme precipitation would affect the flowering phenology in several species of plants by delaying or advancing the peak flowering dates of some species.

Plants flower to reproduce ,to create seeds to produce the next generation. A lot of plants rely on insects or birds or some other pollinator to help with this process. For such plants, changes in flowering time could be a really big problem. If a plant flowers before its pollinators are active, the plant species cannot reproduce or may produce fewer seeds. If there are insects, birds, humans, or other animals that are dependent on those plant species, they could be influenced, as well. Plants and the communities in which they grow are interconnected and critically dependent on each other.

The increases in air temperature with climate warming are often much greater in urban areas than in rural areas. Therefore, phenological responses are expected to be more intense in urban areas, and moderate or evennot-detectable in rural areas. From 1852 through 2006, Concord warmed by 2.4°C due to global climate change and urbanization. Summer-flowering species showed more interannual variation in flowering time than did spring-flowering species, but the flowering times of spring-flowering species correlated more strongly to mean monthly temperatures. In many cases, such as within the genera Betula and Solidago, closely related, co-occurring species responded to climate very differently from one another. The differences in flowering responses to warming could affect relationships in plant communities as warming continues.

Climate change has led to major changes in the phenology of some species but not others. The extent to which flowering-time response to temperature is shared among closely related species might have important consequences for community-wide patterns of species loss under rapid climate change. Henry David Thoreau initiated a dataset of the Concord, Massachusetts, flora that spans ≈150 years and provides information on changes in species abundance and flowering time. When these data are analyzed in a phylogenetic context, they indicate that change in abundance is strongly correlated with flowering-time response. Species that do not respond to temperature have decreased greatly in abundance. Because flowering-time response traits are shared among closely related species, findings suggest that climate change has affected and will likely continue to shape the phylogenetically biased pattern of species loss in Thoreau's woods.