What scientific evidence is there that monarchs are at risk? Provide two examples, at least one of which involves quantitative data. This is NOT asking WHY the monarchs are in trouble but how we know they are in trouble. A lack of milkweed explains why they are endangered, not how we know they are endangered. (Note: Scientific evidence can include qualitative observations (see, hear, feel, taste, smell) or quantitative data. The word "quantitative" means numerical data.)
To obtain scientific evidence that monarchs are at risk, we need to explore research studies and data collected by scientists. By examining qualitative observations and quantitative data, we can gain a clearer understanding of the threats faced by monarch populations. Here are two examples that demonstrate how we know monarchs are in trouble:
1. Quantitative Data: Long-term Population Monitoring
One way to assess the risk to monarchs is through population monitoring. Scientists have been conducting long-term monitoring programs to track the size of monarch populations over time. For example, the Eastern North American Monarch population is estimated by counting the number of overwintering monarchs in specific habitats, such as forests in Mexico and along the California coast. These counts are conducted annually, providing quantitative data that shows trends in population sizes. Over the past few decades, the data collected through these monitoring programs have revealed a significant decline in the number of monarchs, indicating a risk to their survival.
2. Qualitative Observations: Disruptions in Migration Patterns
Another piece of evidence comes from qualitative observations of monarch migration patterns and behaviors. For instance, scientists and citizen scientists have reported changes in the migration routes and timing of monarch populations. These observations show disruptions in the traditional migratory behaviors of monarchs, suggesting that environmental factors, such as habitat loss or climate change, are impacting their ability to navigate and complete their annual migration.
By combining quantitative data from population monitoring programs with qualitative observations of behavioral changes, scientists can build a comprehensive picture of the risks faced by monarch populations. These forms of evidence help us understand the current status of monarchs and the urgent need for conservation efforts to protect their populations.