People are becoming more and more concerned with the climate, and the adverse effects that climate change has on the populations of organisms. The majority agreement within the scientific community is that climate change is very real- in fact, the U.S. Environmental Protection Agency, the National Aeronautics and Space Administration, and the National Oceanic and Atmospheric Administration concur that climate change is occurring and is almost certainly due to human activity. Climate change, also known as ‘global warming’, is a change in global or regional climate patterns, especially higher than average temperatures. The atmospheric concentrations of greenhouse gases have increased since the pre-industrial era due to human activities, the primary source being the combustion of fossil fuels and land use being changed. According to the Intergovernmental Panel on Climate Change, “the overwhelming scientific consensus maintains that climate change is caused primarily to the human use of fossil fuels, which releases greenhouse gases (water vapour, nitrous oxide, methane, and carbon dioxide) into the air”. This is called the ‘greenhouse effect’. The gases trap heat within the atmosphere and prevent it from escaping, which can have a range of effects on ecosystems, such as rising sea levels due to the melting of the polar ice caps which contribute to greater storm damage, warming ocean temperatures that are associated with stronger and more frequent storms, additional rainfall, particularly during severe weather events which leads to flooding and other damage, an increase in the incidence and severity of wildfires threatens habitats, homes, and lives, heat waves that contribute to human deaths and other consequences, and shifting habitats and loss of wildlife species.
Climate has far reaching impacts on biological systems, causing physical and biological changes to occur throughout the entire planet and is impacting regional climates, ecosystems, and the organisms that inhabit them in a number of ways. Climate change disrupts the balance between organisms and their local environment, reducing survival and reproduction and causing irreversible impacts on populations across geographic regions, regardless of location. Animal species can only survive within specific ranges of climatic and environmental factors; if conditions change beyond the tolerance of species, or too rapidly for organism’s evolutionary adaptations, then animals may exhibit ecological responses to these changes. Although changes in climate may benefit some species, in the large part, it causes irreparable damage or even extinction for others. The threat of extinction to species who are unable to adapt or have limited habitat is expected to increase with climatic changes, and the extinction of some species has already been directly linked to climate change. Changes is animal’s phenology, such as migration and breeding has occurred all throughout the world. Changes in the spatial distribution of animals, particularly poleward and elevational shifts, is occurring as suitable habitat disappears or extends beyond its current, “normal” range. Arctic and marine ecosystems are undergoing physical environmental changes that are affecting the species that inhabit them. Temperature change and melting sea ice in the Arctic is adversely affecting the species of the region, and sea level rise, increased sea temperature and higher pH are among the issues changing the plant’s marine ecosystems. Cumulatively, it will alter most, if not all, biological communities and the normal functioning of ecosystems. Changes to ecosystem functions can in turn increase or decrease the rate of human‐driven climate change, thus causing great distress to humankind. In addition to effects of climate variables such as temperature and precipitation, plants may respond directly to rising concentrations of CO2, while aquatic species cope with changes in water chemistry as greenhouse gasses dissolve in water. The earth is already experiencing sufficient climate change that affects biological systems. Well‐documented changes in plant and animal populations are evident of climate change.
The iconic and beloved North American monarch butterfly is one of the species that has difficulty adjusting to our new climate-stressed world. According to EcoWatch, “Populations of this once-common iconic black and orange butterfly have plummeted by approximately 90 percent in just the last two decades. The threats to the species are the loss of habitat in the U.S.—both the lack of availability of milkweed, the only host food plant for monarch caterpillars, as well as nectar plants needed by adults–through land conversion of habitat for agriculture, removal of native plants and the use of pesticides and loss of habitat in Mexico from illegal logging around the monarchs’ overwintering habitat. The new population numbers underscore the need to continue conservation measures to reverse this trend.”
The monarch’s desperate fight for survival also serves as a warning to us all about the potentially irrevocable changes our warming planet faces, and why the global community must pull out all stops to stabilize our climate. Every year, a new generation of these butterflies follows the same path forged by generations before them. The only thing guiding them on this migration is temperature telling them when they need to travel – like a biological trigger setting them in flight. But in recent years, the monarch’s fall south migration from Canada has been delayed by as much as six weeks due to warmer-than-normal temperatures that failed to trigger the butterflies’ instincts to move south. By the time the temperature cooled enough to trigger the migration, it’s been too cold in the Midwest and many monarchs die on their trip south. Climate change has also increased the frequency and intensity of extreme weather events, which can have catastrophic effects on migrating monarchs. In 2002, a severe and sudden storm killed close to 80 percent of the overwintering monarch population in Mexico – a hit from which the species has yet to recover. What’s more, hotter and drier weather conditions have proven to be lethal during the larval stage of monarch development, with direct impacts on the survival and reproductive capacity of adult butterflies. Climate change may also be reducing the growth of vital milkweed habitat, with rising temperatures and severe drought limiting the number of places where monarch butterflies can feed and reproduce. When coupled with other drivers of habitat loss, such as increased herbicide applications across America’s Corn Belt region, it becomes clear why habitat restoration can be key to halting the monarch population’s decline.
Animal migration is the relatively long-distance movement of individuals, usually on a seasonal basis. It is found in all major animal groups, including birds, mammals, fish, reptiles, amphibians, insects, and crustaceans. Unlike most other insects in temperate climates, monarch butterflies cannot survive a long cold winter. Every fall, North American monarchs fly south to spend the winter at roosting sites. Monarchs are the only butterflies to make such a long, two-way migration, flying up to 3000 miles in the fall to reach their winter destination. Amazingly, they fly in masses to the same winter roosts, often to the exact same trees. Their migration is more the type we expect from birds or whales than insects. However, unlike birds and whales, individuals only make the trip once. It is their children’s grandchildren that return south the following fall. Some other species of Lepidoptera (butterflies and moths) travel long distances, but they generally go in one direction only, often following food. This one-way movement is properly called emigration. In tropical lands, butterflies do migrate back and forth as the seasons change. At the beginning of the dry season, the food plants shrivel and the butterflies leave to find a moister climate. When the rains arrive, the food plants grow back and the butterflies return. Monarch butterflies have a complicated life cycle, in that monarch’s emerging at different times of the year do different things. Monarchs that emerge in the spring and summer months become reproductive within a few days. Monarchs emerging in the fall are in reproductive diapause, which is a state of suspended development of the reproductive organs. Even though these butterflies look like summer adults, they won’t mate or lay eggs until the following spring. Monarchs have to know when to fly south, and also when to begin the journey back north. When the late summer and early fall monarchs emerge from their pupae, they are physically and behaviorally different from those emerging in the summer. The shorter days, cooler air, and milkweed senescence (aging) of late summer trigger changes. In the northern part of their range, this occurs around the end of August, when monarchs begin to emerge in reproductive diapause. Diapause is controlled by the nervous system and by hormones. Environmental factors signaling the onset of unfavorable conditions are involved in triggering this physiological response. These factors include day length, temperature, and host plant quality. The iconic and beloved North American monarch butterfly is one of the species that has difficulty adjusting to our new climate-stressed world. Its population has declined 95 percent in the last 20 years, making the orange and black-winged insect a less frequent visitor to American backyards and to Mexico’s famous Monarch Butterfly Biosphere Reserve. Ways to aid in the prevention of shifted migration patterns of the monarch butterfly is to be mindful of one’s impact on the environment, and to not make unnecessary actions that may hinder the earth. Tagging butterflies is a way to better document the migration patterns of the monarch butterflies, to track the movements year-by-year to see if migration patterns have shifted.
Different organisms have different strategies for reproduction. And we are not talking about a nifty array of cheesy pickup lines. At one extreme, some organisms produce a huge number of offspring once in their lifetime and then die or never reproduce again. This type of reproductive strategy is called “big bang reproduction,” or, for the wordsmiths out there, semelparous reproduction. Many fish and insects experience this type of reproduction, including salmon and some species of spiders and butterflies. On the other end of the spectrum, some organisms have only a few, or even a single, offspring at a time, but will reproduce multiple times throughout their lives. Most large mammals, including humans, and many insects utilize this reproductive strategy, called iteroparous reproduction. Reproductive strategies are not an either/or sort of affair; some organisms fall somewhere between semelparity and iteroparity reproduction.
In addition to various reproductive strategies, organisms differ in their survivorship strategies. Some organisms are at high risk of dying early in life, but if they can survive long enough, they have a decreasing probability of dying as the years go on. Well, to a point anyway. Other organisms have a steadily increasing probability of dying while still others live for a long time with the probability of dying only increasing dramatically after a certain (often old) age. These survivorship types are actually called Type I, II, and III and are related to reproductive strategies.
- Type I organisms have a low probability of dying early and are often——iteroparous.
- Type II organisms have a constant probability of dying throughout life and are often somewhere between semelparous and iteroparous.
- Type III organisms have a high probability of dying early and are often semelparous, reproducing once early in life and dying shortly thereafter.
Monarch butterfly reproduction is a complicated process. It is tied into the migratory patterns of the monarch. In the monarch’s summer territory, which includes most of North America, monarchs will mate up to seven times. Each butterfly lives from two to six weeks. The male courts the female in the air, tackles her and breeds with her on the ground. As the monarchs migrate to their summer territory, the female lays her eggs on milkweed plants. The eggs take 3-15 days to hatch into larvae. The larvae feed on the milkweed for about two weeks. At the end of the two weeks, they attach themselves to a twig, shed their outer skin and change into a chrysalis. This happens in just a few hours! In two weeks, a full-grown monarch emerges! As fall approaches, non-reproductive monarchs are born. These are the butterflies that will migrate south. They will not reproduce until the following spring. These late summer monarchs travel hundreds and even thousands of miles to their winter grounds in Mexico and California. These monarchs need a lot of energy to make their trip. They store fat in their abdomens that helps them make the long trip south and survive the winter. During their five months in Mexico from November to May, monarchs remain mostly inactive. They remain perfectly for hours. They live off of the stored fat they gained during their fall migration. When they first arrive at their winter locations in November, monarchs gather into clusters in the trees. By December and January, when the weather is at its coldest, the monarchs are tightly packed into dense clusters of hundreds or even thousands of butterflies. By mid-February these clusters of butterflies begin to break up and the monarchs begin to gather nectar. In the spring, they reproduce and their offspring make the return trip to the north. Due to climate change, and global warming, monarch butterflies might change their complicated breeding process. Global warming causes regions to become warmer, so it may disrupt Monarch butterflies migrations patterns. A monarch butterfly navigates using a sun compass in its mid-brain and circadian clocks in its antennae. But, until now, what makes a monarch reverse its direction has remained a mystery. New research shows that the chill at the start of spring triggers this switch. Monarch butterflies, having flown south in the fall, reorient themselves and start flying north after they’ve been exposed to lower temperatures. With temperature as the critical trigger for the monarch’s northward journey, climate change could be a big spoilsport in its mass migration. A way to test if monarch butterflies are impacted by climate change is to capture fall migrant monarchs and kept them under various light and temperature conditions, then to release the butterflies into a flight simulator. Monarchs maintained under fall temperature conditions should continue due south. Monarchs subject to temperatures similar to those in their overwintering grounds in Mexico of between 4 and 11 degrees Celsius should reorient themselves to fly north. Changing climate conditions to mirror the climate in the “real world” can tell scientists if Danaus plexippus does change their migration patterns in accordance to climate changes.
A limiting factor is a factor present in an environment that controls a process, particularly the growth, abundance or distribution of a population of organisms in an ecosystem. The concept is based upon the Law of the Minimum, which states that the functioning of an organism is controlled or limited by that essential environmental factor or combination of factors present in the least favorable amount that may not be continuously existing but only at some critical period of time. The availability of food, water, nutrients, shelter, and predation pressure are examples of factors limiting the growth of a population size. Monarch numbers can rise and fall for countless reasons. Some examples of limiting factors that impact monarch butterflies are that: Temperatures can be too hot or too cold, precipitation can be too high or too low, food sources can be scarce or abundant, enemies can be many or few, diseases can be deadly or mild, widespread and increasing use of herbicides and insecticides across North America (changing agricultural practices and land use patterns in central and eastern North America are resulting in widespread use of herbicides to sustain crops at the expense of all other competing plants, as a method of weed control along roadways, and to specifically eradicate milkweeds). Temperatures that are higher or lower than normal can greatly impact butterflies migration and reproduction behaviour patterns. To see if monarch butterflies are affected by the limiting factors stated above, butterfly populations in areas could be monitored annually to see if it fluctuates. The percentage of usage of herbicides and insecticides could be calculated, and growth rates and annual natural production of milkweed and then compared to butterfly population change.
Predation is defined as a form of symbiotic relationship between two organisms of unlike species in which one of them acts as predator that captures and feeds on the other organism that serves as the prey. In ecology, predation is a mechanism of population control. Thus, when the number of predators is scarce the number of preys should rise. When this happens the predators would be able to reproduce more and possibly change their hunting habits. As the number of predators rises, the number of preys decline. This results in food scarcity for predators that can eventually lead to the death of many predators. Predators such as spiders and ants attack monarch butterfly eggs and young larvae feeding on milkweed, whereas birds and wasps can prey on adult monarch butterflies. Parasitoids are specialized insects such as small flies and wasps that lay eggs on or inside other insects. Predicting species’ responses to climate change is especially challenging for migratory species, like monarchs, because they could respond to climate change in two fundamentally different ways. First, because they depend on diverse resources across a vast landscape, and because the timing of migration is driven by environmental cues, migratory species could be especially vulnerable to environmental changes. On the other hand, their propensity to move could buffer them against shifting resources, with the outcome being little net change to their population sizes and distributions. Monarchs’ response to climate change will also be driven by how milkweed responds; even if temperatures allow monarch survival, if conditions cause their milkweed host plants to go dormant, become too dry, or die altogether, monarchs will need to move to other areas. Climate change models suggest that monarchs will need to move northward from their current range in June and July, and then return southward in August to track the conditions they currently use for reproduction. Currently, only the spring generation appears to move northward before laying eggs, so this would represent a change from their current migratory pattern. Climate models also predict that the overwintering grounds in Mexico may soon no longer be suitable for monarchs, indicating that the eastern North American monarch population may require different overwintering habitat. Whether monarchs can successfully overwinter in other areas depends in part upon their being able to survive the colder temperatures and different habitats present in areas such as the southern U.S. To minimize the impacts of climate change, it is important to maintain corridors of suitable monarch and milkweed habitat, and ensure that other pressures on their populations are minimized. To test if monarch butterflies are impacted by predation, monarch butterfly eggs and young larvae should be isolated in a lab, and predators such as spiders and ants should be introduced, to see if they (the predators) see the young butterflies as a viable food source.
Greenhouse gases have risen sharply since 1958, primarily due to the Industrial Revolution. Since the dawn of the Industrial Revolution, humans have increasingly been contributing unnatural sources of greenhouse gases into the system, causing the system to become unbalanced. The Earth maintains a habitable temperature due to the Greenhouse Effect, which allows heat from the sun to penetrate our atmosphere, where it is absorbed by the Earth’s surface or radiated out and reflected back to Earth by greenhouse gases in the atmosphere. Without it, the Earth would be a cold and hostile planet, and would most likely be uninhabitable. However, maintaining the natural balance necessary to keep the Earth’s temperature within a range that is viable for life as we know it is a very fine line that can easily be crossed. Greenhouse gases are naturally occurring gases that pose no harm when they are in balance. However, when they are present in excess, the system becomes unbalanced and things start to go awry. Humans negatively impact monarch butterflies livelihood by the excess usage of pest/herbicides, through the effects of global warming, etc. For example, since the monarch butterfly overwintering habitat was discovered in the mountainous fir forests in central Mexico three presidential decrees have been issued (1980, 1986, 2001) to protect it. But these forests are the source of livelihood for many local people, whose activities (wood extraction and clearance for subsistence farming) represent a major threat to the forests, and thus to the butterfly population. This study identifies important deforestation, disturbance, and recovery processes caused by human activities in the protected areas and their surroundings. Contrary to our expectations, the protected areas have been most negatively affected by human activities, whereas areas devoted to multiple uses have been more adequately preserved. To investigate the effects of human impact on monarch butterflies, consider protecting areas and observing the monarch butterflies in the protected habitat versus monarch butterflies in the “wild”.
Above is a Pearson r/ CORRELA model for Danaus Plexippus. Overall, the Pearson product moment correlation coefficient for the data sets was .3873927646, which is insignificant. Therefore, there is little to no correlation between annual temperature and population of Danaus plexippus in Los Angeles, California in the years of 1950 thru 2015. Ergo, the hypothesis “ My hypothesis is that climate change will affect Danaus plexippus’ migration patterns negatively.” The hypothesis is not completely false, because as compiled by the evidence beforehand, it is apparent that climate change does indeed affect Danaus plexippus negatively. However, the population of the species has grown substantially, and not diminished (in Los Angeles, California).