Insects exists almost everywhere on the planet and up to this point, we've discussed some of the many different habitats where insects can be found. Despite millions of years of evolutionary success, some insect species are now endangered due to a variety of factors most of which are driven by human activities. As human impacts on the planet become increasingly severe, the field of conservation biology will become ever more important. The goal of conservation biology is to conserve threatened species and overall biodiversity. This requires a multidisciplinary approach that involves scientific fields such as conservation genetics and population ecology, as well as economic and governmental policies. Most conservation projects initially measure biodiversity and the relative abundance of each species present in the studied ecosystem. This is combined with an assessment of ecosystem function and population data for the species of concern. Using this information, researchers can determine the response of the target species to environmental changes such as habitat modification, climate change, competition from invasive species, and other human-induced factors. As of 2017, the International Union for Conservation of Nature or IUCN has identified over 730 endangered insect species and over 650 species that are vulnerable. This number is a gross underestimate since most species of insects are not monitored and many remain undiscovered and undescribed. This does, however, highlight the growing number of insect species that are at risk of extinction which warrants a focus on insect conservation. There has been a recent upsurge in public attention to insect conservation which has been driven in part by the recognition that some insect populations and species are being lost at a rapid rate. For example, a study conducted in Germany examined populations of flying insects monitored by amateur entomologists all over the country since 1989. Data was collected in a standardized way by capturing flying insects in malaise traps like those we learned about in Module 1. Each year, the samples were weighed and the data analysis revealed a disturbing pattern. The average weight of the insect samples caught annually in these traps fell by 76 percent over the 27-year period since the study began. This is particularly concerning since these traps were set up in nature reserves, areas where the landscape is protected and where habitats should be the most hospitable for insects. This trend could be even more dramatic in areas heavily impacted by human activity like agricultural and urban areas. We see similar patterns in insect populations here in North America as well. Populations of native pollinators such as the rusty patched bumblebee, Bombus affinis, have declined drastically. This bumblebee currently in habits only 0.1 percent of its historic range. It's pollination activity helps ensure the survival of native wildflowers and it pollinates flowering agricultural crops like plums, apples, and cranberries. There are many reasons to support insect conservation and arguments can be ethical, philosophical, or practical. Depending on the underlying reason, the goals and approaches to conservation efforts will differ. Insects play important roles in the maintenance of ecosystems and ecological processes. Several insect species heavily influence terrestrial ecosystems. Ants and termites, for example, are major ecosystem engineers. They modify the soil during nest construction and facilitate the movement of inorganic and organic materials in and out of the ground, which serves to enrich the soil. Furthermore, as we discussed in Module 5, these insects act as decomposers to break down organic matter in soil and leaf litter. This activity releases nutrients back into the soil that can be absorbed by plants. The impact of insect decomposers is significant. A diverse community of arthropod decomposers ensures that the nutrient cycle continues efficiently, which helps support natural communities. Insects also play lesser known roles in the function of ecosystems. For instance, seed-feeding insects such as ants sometimes help plants disperse seeds. Another important ecosystem service provided by insects is pollination. As we discussed in Module 7, many plant species depend on insect pollinators for seed production and population viability. Insects are efficient pollinators that limit pollen waste and in some cases enable rare plant species to reproduce successfully despite sparse populations. From an anthropogenic perspective, insect pollinators help maintain populations of plants that we use for food, construction, and horticulture. Together, insect-driven soil movement, nutrient cycling, herbivory, and pollination activities help determine local vegetative diversity and abundance. This in turn influences the diversity of organisms further along a food web and the entire community of organisms. Herbivorous insects help to control invasive and native plant populations. In fact, most plants that are defined as invasive have been released from their associated herbivore community. We have already learned of one example of the use of herbivorous insects to control invasive plants in Module 10, in which herbivorous weevils have been introduced to control the invasive toadflax weed here in North America. Herbivorous insects are integral to maintaining ecosystem balance in native ecosystems as well as plant growth is often limited by herbivorous insects. For example, a vine native to the Southeastern United States accumulated greater biomass and had a higher growth rate when experimentally relieved from herbivory than when the herbivore community was intact. This shows that native herbivores limit the growth and spread of this plant in its native range. Insects that feed on or parasitize other insect species help to regulate prey population sizes and moderate the impacts of prey species within the ecosystem. Insects also provide food resources for many larger predatory organisms in an ecosystem. Maybe, the only good thing about mosquitoes is that they're food for dragonflies and insectivorous birds. Disturbance of insect populations can substantially influence predator populations. In fact, studies performed across Europe identified a correlation between declines in bird diversity and shrinking invertebrate prey populations. Some insect specialists like the spotted flycatcher in England have declined by more than 90 percent in the past 25 years. Others that specialize on larger insects such as the red-backed shrike have even recently become locally extinct. Insect species can be used for biomonitoring of fragile ecosystems. Insects can indicate environmental health in part because they are sensitive to specific habitat requirements and populations can respond quickly to environmental change. In addition, the discovery and protection of rare and endangered insects often leads to the protection of rare plants and animals within the same habitat. Biomonitoring assesses the general condition and quality of an ecosystem based on the responses of indicator species to changes in the environment. Insects are easy to sample and are often good indicators of ecological changes. Depending on the species of insects being used in biomonitoring, different types of ecosystem data can be collected. For example, the presence of different freshwater insects is often used to assess water quality in natural systems. In addition to chemical and physical measurements of an ecosystem, monitoring of biological components in the system can provide information about important environmental changes. In terrestrial ecosystems like forests, butterflies can serve as indicator species because they are sensitive to climate and ecosystem changes, are easily recognized, and often have long-term population and distribution data. Let's hear from an expert on this subject. Lisa Lumley is an acarologist at the Royal Alberta Museum here in Edmonton who monitors soil mite populations across the province. So I'm an ABMI mite taxonomist and mostly I work with Alberta mites. Originally, when I started my career in entomology, I worked with the Spruce Budworm species complex, and that's our forest lepidopteran. More recently, I've had the opportunity to start working with Oribatid mites and that's for bio-monitoring. That's with the Alberta Biodiversity Monitoring Institute and the Royal Alberta Museum. So the purpose of bio-monitoring is really to determine if an ecosystem is healthy and functioning. A lot of thought and consideration went into choosing Oribatid mites as a bio-indicator by the Alberta Biodiversity Monitoring Institute and there were some practical reasons. So, we can sample soil, which is easy to do by technicians in the field. So, they don't need to know the identifications. Because we're sampling soil, we can do it in a single sampling event. So, we don't need to go set up traps and then come back. So, that really reduces the amount of field costs. Then Oribatid mites have been shown to be good bio-indicators in other studies. So ABMI, the Alberta Biodiversity Monitoring Institute took that into consideration and their life history traits are conducive to being bio-indicators. So, they're K-selected, which means that they have quite long lives for arthropods. So, they live from one to seven years and the females have low reproductive rates, so they produce few young, that means overall that they have a ton of stable populations which makes it easier for us to do single sampling events because they're not as phenologically diverse. Some species respond positively to disturbance. For example, in agricultural fields we'll find certain species that do really well there and then others they're very specific, they need specific habitats. We will only find them, for example in aquatic habitats or associated with a specific Moss, as an example. If it gets disturbed, then they're not there anymore. The ABMI surveys 1,656 sites and they're randomly selected and they're in a 20 kilometer grid across the province. So, we have a site approximately every 20 kilometers. This means that we're collecting or surveying in every ecoregion and sub-region within the province. I would say that they're probably in line in terms of difficulty as other arthropod groups. So, to get to the family and genus level, our technicians and summer students and other students can come in and learn those identifications in a very steep learning curve, but they can usually get really proficient at it within one to two months and then when you get into the more difficult species, then it becomes more time. So you really need to develop an eye for the taxonomic characters. By understanding where species live, we can find rare species, we can find biodiversity hotspots that can help plan-managers to figure out how to manage different areas. Then if we continue to monitor after we've gotten that foundational knowledge, by continuing to monitor, we can then start to look at environmental change and then we can start to ask is it over large areas? Is it regional? Is it site specific? And that can help us to say, is this an environmental change that's climatic or is it site-specific where maybe it's contamination? So, we can start to really ask those ecological-type questions that are more helpful in terms of remediation of ecosystems that look like they're struggling functionally. Arthropods are typically much more abundant in a site and much more diverse and they have many different roles in the ecosystem. They have a variety of roles in terms of being generalist to specialists. So, with all that information we can really tease apart questions about an ecosite. Oribatid mites and spruce budworm. I can't take that out of my heart either, they're both in there. Data from bio-monitoring studies can help us understand natural processes that affect populations. For example, bio-monitoring may reveal the impact of specific disturbances such as a forest fire or a flood on an ecosystem over short and long-term intervals. Bio-monitoring also allows researchers to study how the behaviour, diversity, and abundance of a target species respond to human-induced stressors such as pollution and habitat fragmentation. This can inform conservation efforts. Preserving endangered species is not only important for environmental health, but is actually recognized as a worthwhile economic investment. Each year approximately $1.5 billion is spent implementing the US Endangered Species Act which was passed in 1973. Populations of native pollinators that are conserved by this act contribute more than $3 billion per year in pollination services for a variety of crops. Insects and other arthropods protected by this act also provide food for wildlife, allow natural biological control, and recycle nutrients, services that altogether are estimated to value more than $57 billion per year. In addition to the economic return provided by the enforcement of the Endangered Species Act, the program has likely prevented the extinction of at least 200 species. Insects provide critical ecosystem services through activities such as pollination, nutrient cycling, and predation. As important components of food webs across multiple trophic levels, they also have critical regulatory and functional roles within ecosystems. All in all, insect diversity is essential to keeping ecosystems intact and to maintaining a resilient and well-functioning biosphere. Without insects pollinating our crops and decomposing dead matter, our lives as we know them on the planet would slowly cease to exist. In the next two videos we will learn about various human-driven factors that are contributing to declines in insect diversity.
