Climate Change & Butterfly Phenology

Objectives 

Students should be able to

• Understand basics about climate change and where to learn more

• Connect organism level data (emergence/flight time) to environmental data using graphs focused on phenology

• Evaluate the advantages and limitations of specimen-based data in addressing specific biodiversity questions

• Understand need and usage of scientific names

• Be able to describe and compare scientific communication strategies, including the meaning of peer-review

• Be able to locate, read, and evaluate a scientific paper

Introduction

Phenology is the study of the timing of cyclical events in an organism's life cycle, such as the flowering of plants, emergence of worker bees from the hive, or the migration of birds. The timing of critical life stages can be triggered by external environmental cues such as seasonal changes in temperature, precipitation, or photoperiod (day length).

As global weather patterns alter or fluctuate due to climate change, an organism's phenology may shift in response to a change in these cues. For example, spring temperatures are becoming warmer in recent decades due to climate change, resulting in many plants and animals starting their spring activities earlier than they used to. 

On one hand, it's encouraging that many organisms are responding to rapid changes in their environment. However, when species respond at different rates it can disrupt ecological relationships. Mutualistic relationships between plants and animals can be disrupted if they have different sensitivities to warming spring temperatures. For example, if a host plant is able to shift its phenology to track warmer springtime temperatures but its pollinating insect can't respond at the same rate, they may end up out of synch with each other. This is known as a phenological mismatch, and it can have dire consequences. The plant may lose pollination service and not be able to reproduce, and the pollinating insect may lose its food source (nectar from flowers). Phenological mismatches can occur between any interacting organisms such as predators and prey, diseases and hosts, or competitors exploiting a shared resource. 

To study the impacts of climate change on phenology we need to examine long-term historical patterns and trends in both the environmental conditions and phenologies of the species of interest. We need current and historical data on when and where species occur, the timing of phenological events (e.g. emergence, flowering dates, peak flight), and key environmental variables that can initiate phenological transitions (e.g. temperature, precipitation). This means we need long-term data for both the organisms we study and the ecosystems they occupy. Fortunately, we are in the data rich era of science! Environmental data and data from natural history collections, professional scientists, amateur naturalists, and long-term weather stations provide the information that is necessary to investigate phenological changes.

The role of natural history collections in studying climate change

Natural history collections data are based on a physical specimen that was collected by a scientist, carefully preserved, and stored in a museum, university, or research collection space, much like books in a library. These collections serve as warehouses for all kinds of biological data such as phenology, taxonomy, evolution, and ecology of the species. Each specimen has information beyond the physical object itself. A specimen contains valuable metadata (e.g., collection date, location, habitat, images) and is accessible for repeatable, iterative, and expanded observations when physical verification is needed, new questions arise, or new investigative techniques are developed. 

Recent technological advances allow researchers to use specimens to study past biological phenomena such as molecular variation, historical environmental conditions, presence of environmental toxins, and host-parasite assemblages. Many of these specimens were collected far before some of these technologies were created! This highlights the importance of systematically collecting and storing information for current and future uses. 

Natural history collections provide a source of biodiversity data that is unequaled in temporal, geographic, and taxonomic complexity and unique in its ability to allow researchers to verify and expand the data by returning to the physical specimens on which they are based. Further, these data can be combined with other data sources to inform research questions. For example, climate data can provide information on historic temperature and precipitation, citizen science observations can provide contemporary species occurrence information, and genetic data can provide information about evolutionary history.