Now that temperatures are dropping and we are in late fall/early winter (although it seems as though it has just become fall down here in Tennessee), you might be wondering if there is a difference in how invasive and native plants respond to autumn. Or maybe you weren’t, but you are now! In ecology, “phenology” is the word we use to describe the seasonal changes in organisms. This might include the timing of emergence of insects, of bird migrations, or of plant aging, which is called “senescence”. As you know, in deciduous forests, many plants drop their leaves in the winter. This is usually caused by changes in light levels. As the days get shorter, plants respond by reabsorbing nutrients from their leaves, and then dropping them to prevent damage from frost and freezing temperatures in the winter. At this point they are no longer doing photosynthesis, which is the process by which plants make energy from sunlight. Different species respond in slightly different ways and often their leaves senesce at slightly different times.
Dr. Jason Fridley from Syracuse University studies the differences in phenology between native and invasive plants. From his research, we know that in the deciduous forests of the eastern United States, invasive plants such as honeysuckle remain photosynthetically active for an average of four weeks later into the fall than native plants! This delayed phenology gives invasive plants access to more sunlight because the sun isn’t being absorbed by leaves of natives. They can make energy for a longer amount of time, which may give them an advantage over some native plants. Basically, they can take advantage of a longer growing season! Although this is likely not the only means by which these invasive plants have an advantage over natives, it is definitely an important factor. When you walk around outside in late fall, keep an eye out for those invasive plants with delayed phenology that are still photosynthesizing!
For more reading, here is a link to Dr. Fridley’s article:
Did you know that most plant roots are actually really terrible at absorbing adequate resources from the soil? You probably know that plants need water, but they also need nutrients such as phosphorus and nitrogen from the ground. Some researchers have estimated that 90% of plants have to rely on fungi to help them do this basic and essential task. This is something that most of us might assume that plants have no problem doing. This is just one of many strange facts that I have picked up along the way about plants. Now, I am aware that I am more passionate about plants than the average person. However, they are so important to our day-to-day existence that life can so much more interesting if we see the beauty and importance of the organisms all around us! Plants fundamentally form our clothes, our fuel, our food, and of course the landscapes around us. Through this blog, I want to share with you some of the countless facts about plants that have shocked me, amazed me, or are just plain weird.
I suppose I should explain who I am before I delve into the world of plants. I, like most people, was totally and completely uninterested in plants growing up. The occasional flower would catch my eye, and I did like spending time outdoors, but other than that I couldn’t have cared less. Even though I knew I was generally interested in biology, I dreaded the plant-focused sections of my introductory biology classes. However, reproductive strategies had caught my attention. I joined a lab that focused on plant breeding systems, and fell in love with the crazy strategies that plants can evolve to make viable offspring. From there, I went on to graduate school at the University of Tennessee, in Knoxville, TN. I am merging the fields of invasion biology and reproductive biology in my research project. I am working to understand how invasive plants impact reproduction in native species. The invasive species I study (Alliaria petiolata or garlic mustard) is thought to cause stress in native plants by killing the fungi they rely on to acquire water and nutrients. Sound familiar? Yup, this plant could potentially affect those 90% of plant species that rely on fungi.
My point in explaining all of this is that I am broadly interested in a whole range of things including biodiversity, invasive species, species interactions, and plant reproduction to name a few. Therefore, for future posts you can expect a variety of things that I find interesting, and I hope I can continue to convince you that plants are worth knowing.