Why do we care about the extinction of seemingly meaningless species across the planet? It seems like a simple question with obvious answers of decreased biodiversity and alteration of the food chain for that particular ecosystem. The biggest truth behind our interest in these species dying off is that they play a major role in indicating environmental changes that we might not see. Indicator species are species chosen for their sensitivity to specific characteristics of the environment they live in. This is typically reflected in the species’ abundance or absence. Species can range from insects to mammals and are used to measure a variety of environmental characteristics. Some of the most prominent categories of indicator species today include birds, bees, and butterflies.
Figure 2: Red-cockaded woodpecker habitation in the United States
Birds acting as indicator species are the most noticeable to communities as flocks diminish in presence. Birds as a class “Aves” key us into a multitude of environmental changes in their respective ecosystems. Birds like the red-cockaded woodpecker are useful indicators of habitat quality as they have specific nesting requirements. These requirements of tree trunk diameter, tree species, and available food sources are effected by deforestation, pollution in the ecosystems, and climate change. Other signs of habitat insufficiency that birds are often used to indicate are water quality and food sources dying off (decreased biodiversity). Pollution, particularly in the form of DDT and heavy metals, is apparent in the population’s health and growth due to the effects they have on shell strength and metals found in feather samples.
Figure 1: Number of bee colonies (in millions) in the United States over time
Bees are an obvious indicator as we frequently hear about their declining numbers. Bees are responsible for about $30 billion in crops each year because they pollinate 70/100 crops that feed the world. While there would be a massive decrease in food production and population decline would ripple up the food chain, we would also lose a vital indicator of high concentrations of heavy metals in an area and pesticide use. Bee population decrease is being caused by increasing temperatures due to climate change, pesticide use, and the invasive, parasitic Varroa mite.
Figure 3: Butterfly population in Mexico based on hectare occupation
Butterflies are the most sensitive of indicator species making them the best-monitored insects. The temperature of their surroundings makes a huge difference in when they migrate, reproduce, and even die. Just 1*C difference in temperature of the environment can effect migration patterns by days. Temperatures above 35*C (95*F) can prove lethal, and drought means that eggs do not hatch. Sensitivity to temperature alone proves butterflies vital to monitoring subtle changes in climate. Butterflies’ sensitivity to pesticide use, drought, and habitat loss clue scientists in to other human-caused problems.
President Obama issued a memorandum in 2014 to create the Pollinator Health Task Force to promote health of and protect pollinator species in the United States. This lead to state legislature creating their own “Pollinator Protection Act”s to guide the agriculture industry to decrease use of neonicotinoid pesticides, develop new seed planting technologies, and curb herbicide usage in monarch butterfly habitats as well as promoting use of new Varroa mite control products. States that have created PPAs of their own include Maryland, Oregon, California, and more.
While these recent implementations have so far proven effective, President Trump might delay progress made in protecting these pollinators, specifically bees. The endangered rusty patch bumblebee, a key North American pollinator, was the target of a recovery plan from the US Fish and Wildlife Service back in February, but President Trump put a freeze on its entry to the endangered species list and regulations to begin to recovery of the bee. The freeze was lifted, and the recovery plans were implemented, but it still caused environmentalists fear for the future of the insect.
Is it possible that more policy similar to the Pollinator Protection Act and programs like the Pollinator Health Task Force could have success in protecting indicator species in the United States and worldwide? What kind of an effect do you anticipate these pollinator policies having on future policy regarding climate change, water/soil safety, etc?