Photo of the Week – September 9, 2011

This week our Platte River Prairies are in full autumn regalia.  Everywhere you look, big yellow composite flowers, especially sunflowers and goldenrods, dominate the visual landscape.  At least 15 different species of yellow flowers are blooming right now.  They are set against the golds and purples of the warm-season grasses, which are also in full bloom. 

Maximilian sunflowers have just started to bloom, joining a crowded field of five other sunflower species in our prairies. (Click on the photo to see it full-screen)

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A grasshopper sits on one of the last remaining blossoms of stiff sunflower, an early blooming perennial sunflower - most common in the sandier soils of our prairies.

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Our seed harvest crew is swimming through the tall grasses and late yellow flowers to find ripe seeds from shorter plants that bloomed earlier this year. In this photo, Mardell Jasnowski (left) and Nanette Whitten (right) look for black-eyed Susan seeds in the burned/grazed portion of a prairie. A light stocking rate and an unexpectedly wet season has left even this grazed area with plenty of tall growth.

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The abundance of yellow makes flowers of any other color really stand out. In this photo, Mardell is harvesting seed near a particularly showy dotted gayfeather plant.

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This cluster of Maximilian sunflower blossoms was arrayed nicely for a photo...

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A tree cricket feeds on pollen from a stiff sunflower, while two grasshoppers do the same on another flower in the background. Tree crickets are omnivorous - feeding on both small insects and plant material.

In another week or so, some of the yellow flowers will start to fade, and the rest will be joined by the whites and lavenders of late season asters.  In the meantime, yellow is definitely the color of the week. 

Enjoy the autumn!

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.