Pussytoes and Early Season Pollinators

I drove out to our family prairie yesterday to look for some early spring activity.  I scared up a couple of turkeys and a big owl, watched a red-tailed hawk soar for a while, and listened to the western meadowlarks tuning up for the breeding season.  No snakes were to be found, but there were plenty of leopard frogs along the edge of the pond.  I’d hoped to see some wildflowers, but there weren’t many blooming yet.  Apart from abundant sun sedge (Carex heliophila) plants on the steeper slopes, the only blooms to be found were patches of pussytoes (Antennaria neglecta).  Not that there’s anything wrong with pussytoes!

Pussytoes (Antennaria neglecta) in the Helzer Prairie, south of Aurora, Nebraska

Our prairie sits right on the transition between tallgrass and mixed-grass prairie in Nebraska.  As such, it can be dominated by big bluestem and indiangrass, or by western wheatgrass, side-oats grama, tall dropseed, and other shorter grass species – depending upon recent weather and management.  Part of the property is unplowed prairie, but much of it was seeded in the early 1960’s by my grandpa soon after he bought the property.  The formerly cropped areas were seeded with grasses, but have also been colonized over time by many of the forb species from the hillier unplowed prairie on the site.

Pussytoes grows well in both the unplowed and seeded portions of the prairie.  It can be found in small patches consisting of a few individuals, but also in living room-sized populations.  The plant is considered to be allelopathic and reduces the height of surrounding plants, which makes large patches fairly easy to see.  It also seems to do well in the areas of the prairie favored by grazing cattle.  (Whether this is because the cattle are drawn to the shorter grass or because the pussytoes do well in heavily grazed areas I can’t tell – it’s likely both!)

Many of the pussytoes flowers were just starting to emerge, meaning that they were only an inch or so off the ground.

Regardless, the pussytoes had the wildflower blooming stage to themselves on this early April day.  I needed to scratch my itch for wildflower photography after a long winter, so I laid down with my tripod and focused in on a few plants.  As often happens when I take the time to sit down in a prairie, I noticed other things around me.  This time it was the buzzing of pollinators who had also noticed that pusseytoes were blooming.  As I watched, I counted at least 8 species of pollinating insects bouncing from flower to flower, looking for those with pollen-laden anthers.  Most of the insects were flies, but a few bees and a moth were among the visitors as well.  Elsewhere on the prairie I saw some orange sulphur butterflies too, but never actually saw one land on a pussytoes flower.

This was one of several fly species busily visiting pussytoes flowers.

Another fly species (about the size of a house fly).

A much smaller fly, wiping pollen off its leg with its mouthparts. (I assume - or wiping its mouthparts with its leg, who can tell?)

This was the only bee species I saw, though I thought I heard a bumblebee go by...

Since our prairie is a 106 island of prairie in a landscape consisting mostly of cropland, these pussytoes were not only the sole source of pollen in our prairie – they were just about the only thing to pollinators to eat for miles.  Not even the dandelions in the neighbor’s creek bottom had started to bloom yet.  I’d never thought of pussytoes as a critical plant for pollinators, but apparently I underestimated this low-stature plant.  I’m guessing it’s not the first time its been overlooked…

Yes, I know, this looks like the same fly species shown above, but I really like its face, and this photo shows it off better than the other one does...

Photo of the Week – April 7, 2011

This poor light-colored grasshopper nymph was nicely camouflaged against the dormant grass in this prairie until a prescribed fire drastically changed its surroundings.  This nymph was fortunate to survive the fire, but will now have a bit more trouble hiding from predators!

Fire is an integral component of prairie ecology, and an essential part of prairie management, but that doesn’t mean that it’s harmless.  Not only does fire drastically change habitat conditions, it can also lead to the death of animals unlucky enough to be in the wrong place at the wrong time.  Anyone who has conducted numerous prescribed fires has seen the remains of snakes, turtles, and other animals that weren’t able to get out of the way or find refuge underground before the fire swept over them.  Insects that overwinter in the thatch or standing dead vegetation are especially vulnerable to fire.  In cases where a small subset of a population is killed by fire, little long-term damage is done to the overall survival of the species, and loss to fire is not really different than predation, diseases, or other causes of mortality that have always been part of life and death in prairies.

However, species that live in small isolated prairies are much more vulnerable to local extinction from fires (and other causes like diseases, floods, etc.).  The small size of the populations in those prairies make it more likely that the entire population will be affected by an event.  More importantly, the isolation of the prairie means that recolonization from other sites is not likely.  Once a species is gone it’s gone.

The potential harm to vulnerable species shouldn’t prevent the use of fire in prairies, but it should be an important consideration as you plan your fire, especially in small isolated prairies.  Reserving a significant portion of a prairie in an unburned state each year, and not obsessing about completely blackening the entire burned portion can help maintain healthier populations of vulnerable insect and other prairie species.