Disappearing Pollinators By Ed Powers

Picture Courtesy University of Leeds

These hard-working animals help pollinate over 75% of our flowering plants, and nearly 75% of our crops. Often we may not notice the hummingbirds, bats, bees, beetles, butterflies, and flies that carry pollen from one plant to another as they collect nectar. Yet without them, wildlife would have fewer nutritious berries and seeds, and we would miss many fruits, vegetables, and nuts, like blueberries, squash, and almonds . . not to mention chocolate and coffee…all of which depend on pollinators.  But they are disappearing and at an alarming rate.  While all pollinators are important, we will be focusing on honeybees (though many of the causes relate to all pollinators not just honey bees).

Picture Courtesy National Audubon Society

There are a number of pressures on pollinator populations, but there is lack of information about their relative importance or to what extent they have led to the declines we are now seeing. Possible causes include

1. The loss of basic habitat requirements in our landscapes such as floral resources other than flowering crops that provide food to pollinators. Flowering crops are usually in bloom for only a fraction of a pollinator's life cycle, so in order to survive and reproduce effectively they need alternative sources of nectar and pollen throughout their active season. The loss of other basic needs such as nesting sites and materials may also contribute to the problem.
2. The simplification of the landscape with the promotion of monoculture crops, larger fields and less traditional features such as hedgerows, set-aside land and wildflower rich grassland. This results in less of the food and nesting resources occurring in landscapes and the isolation of resource-rich semi-natural habitats.
3. The intensive use of agro-chemicals including pesticides that may have a direct effect on insect pollinators, and herbicides that remove important floral resources. Pesticides are substances used to eliminate unwanted pests. Insecticides are a subset of pesticides focusing on insects. Unfortunately, honey bees are insects and are greatly affected by insecticides. There are several ways honey bees can be killed by insecticides. One is direct contact of the insecticide on the bee while it is foraging in the field. The bee may then die and does not return to the hive. In this case the queen, brood and nurse bees are not contaminated and the colony survives. The second, more deadly, way is when the bee comes in contact with an insecticide and transports it back to the colony, either as contaminated pollen or nectar or on its body.
4. Pests and diseases affecting domesticated pollinators such as honey bees and which may spread to wild populations.
5. Over-reliance on domesticated honey bees for pollination which may compete with wild pollinators for scarce resources.
6. Colony Collapse Disorder is the phenomenon that occurs when the majority of worker bees in a colony disappear and leave behind a queen, plenty of food and a few nurse bees to care for the remaining immature bees and the queen.  Although once thought to be of a major impac,t it is now less impactful.

Research into these pressures has typically focused on a single cause, but in reality they may interact with each other. For example, a lack of floral resources occurring in the countryside due to intensive farming may lead to nutritional stress in insect pollinators which in turn can make them more vulnerable to attack from pests and diseases or to the effects of pesticides. There is therefore a need for research to identify the underlying causes of pollinator declines and the interactions between them, and this is one of the broad aims of the work funded by the UK Insect Pollinator Initiative.

Picture Courtesy of University of Leeds

Back ground Information for article gathered from:

2017 University of Leeds, Leeds/agriland-Possible Causes of Pollinator Decline.  

Colorado State University extension fact sheet Pollination of Fruit Trees

USDA/Natural Resources Conservation Service/Insects & Pollinators

Natural Resources Conservation Service/ Wildlife Management Institute/ Native Pollinators

Weeds, NOT landscape plants, by Todd Hagenbuch

This time of the year, flower gardens throughout the area are in full bloom with all kinds of beautiful foliage.  Some of those flowers are annuals, some perennials.  Some are from seed, others grown from bedding plants, and others gifts from friends or neighbors.  Some are natives, some are introduced, and more importantly, some are actually noxious weeds.

A noxious weed is any weed that has been determined by the State of Colorado to negatively impact or threaten our native or agricultural ecosystems.  Typically a plant that was introduced from Europe, Asia, or Africa, these weeds have abilities to out-compete our native plants, meaning they spread unchecked throughout our landscape.  Unfortunately, many of these plants are still being planted in yards and gardens throughout our area, and are sold by nurseries or seed companies and purchased by unsuspecting homeowners who are looking for spreading, low maintenance plants with attractive flowers.  While that’s exactly what they get, homeowners also get themselves and their neighbors into a mess, not to mention that they are breaking the law by planting these noxious weeds.­

List A noxious weeds need to be eradicated, by law, whenever they are found on any property in order to protect communities and the state as a whole. There are several plants that I see in landscapes that are List A species.  

In our area, Orange hawkweed (Hieracium aurantiacum) is one of the biggest List A offenders. It is believed that this plant was sold and planted by a local Steamboat Springs landscaper for several years in the recent past. The orange flowers are beautiful, but this plant spreads quickly and can invade roadsides, lawns, common areas, and more.

Myrtle spurge (Euphorbia myrsinites) is another common plant in home landscapes that needs to be eradicated.  The leafy plant has yellow-green blooms, which are really small flowers surrounded by petal like bracts.  I see this plant in a yard near my sister-in-law’s house when I visit her and it gives me heartburn whenever I see it.

Purple Loosestrife (Lythrum salicaria) is a perennial plant that is found in our area, especially in wet areas. While it looks a lot like our native fireweed, this bad actor can create millions of seeds per plant and those seeds remain viable for 2-5 years. If you find this one in your yard, you’d better get rid of it quickly!

List B noxious weeds are weeds that need to be controlled to limit spread.  You should control these in a yard situation, too, as they can escape to other areas quickly and cause havoc.

Dame’s Rocket (Hesperis matronalis) is a 4 foot tall plant of purple or lavender colored, 4-petaled flowers. It has been included in many wildflower seed mixes, and tends to escape into pastures, forests, and more.

Scentless chamomile

Oxeye Daisy (Chrysanthemum leucanthemum), not to be confused with the larger Shasta Daisy, is another flower that is sometimes included inappropriately in wildflower mixes and is prevalent in our area, both in landscapes and in pastures.  

Other List B species to be aware of include Common tansy (Tanacetum vulgare) and Scentless chamomile (Matricaria perforata).  Attractive plants on Colorado’s Watch List (plants that are a potential threat to our environment) include Baby’s breath (Gypsophila paniculata), and Yellow flag iris (Iris pseudacorus).  Follow this link for a detailed list with photos: https://www.colorado.gov/pacific/agconservation/noxious-weed-species.

Knowing what you’re planting in your yard is the first step in helping to halt the spread of noxious weeds. Always check wildflower seed packets before planting and check with your local Extension office to see if something you’re considering planting is actually a noxious weed, or if you need help identifying suspicious plants.  Your neighbors will thank you and you can continue to be a law-abiding citizen.

Todd Hagenbuch is the Agriculture Extension Agent for CSU Routt County Extension.