Ecology and climate change Flashcards
Climate change definition
- Long-term changes in average weather patterns on Earth.
*Modern climate change has been caused by anthropogenic activity.
Anthropogenic (human) causes of releasing greenhouse gasses into the atmosphere.
Impact of the industrial revolution
According to the National Oceanic and Atmospheric Administration (NOAA), the global average carbon dioxide concentration in the atmosphere has increased by 50% since the Industrial Revolution. In 2022, the global average carbon dioxide concentration reached a new record high of 417.06 parts per million (ppm)
When was climate change discovered?
Eunice Newton discovered global warming could be caused by CO2 output in 1850’s however she was not credited in past years due to sexist culture around science in the past. She was the first scientist to predict rising CO2 levels could affect atmospheric temperature and climate.
John Tyndall 1859 Did practical experiments using a gas tube. Discovered water vapour’s ability to absorb more heat than other gasses.
Svante Arrhenius in 1896 was the first to predict the extent to which carbon dioxide emissions would affect atmospheric temperature through the greenhouse effect.
Historical climate changes
Weather pattern changes occur due to changes to the Earths orbit (naturally)
There is evidence that due to human impact
- Current warming rate is greater than any seen in the last 10,000 years
Which gases are responsible
Greenhouse gases refract longwave radiation more efficiently thus resulting in warming
CO2, 100 year lifespan
Methane, 12 year lifespan
Nitrous oxides (from farming) and halogen gases (from insulation) also contribute
Future global warming predictions based on human actions
SSP1: The sustainable and “green” pathway describes an increasingly sustainable world. Global commons are being preserved, the limits of nature are being respected. The focus is more on human well-being than on economic growth. Income inequalities between states and within states are being reduced. Consumption is oriented towards minimizing material resource and energy usage.
SSP2: The “Middle of the road” or medium pathway extrapolates the past and current global development into the future. Income trends in different countries are diverging significantly. There is a certain cooperation between states, but it is barely expanded. Global population growth is moderate, leveling off in the second half of the century. Environmental systems are facing a certain degradation.
SSP3: Regional rivalry. A revival of nationalism and regional conflicts pushes global issues into the background. Policies increasingly focus on questions of national and regional security. Investments in education and technological development are decreasing. Inequality is rising. Some regions suffer drastic environmental damage.
SSP4: Inequality. The chasm between globally cooperating developed societies and those stalling at a lower developmental stage with low income and a low level of education is widening. Environmental policies are successful in tackling local problems in some regions, but not in others.
SSP5: Fossil-fueled Development. Global markets are increasingly integrated, leading to innovations and technological progress. The social and economic development, however, is based on an intensified exploitation of fossil fuel resources with a high percentage of coal and an energy-intensive lifestyle worldwide. The world economy is growing and local environmental problems such as air pollution are being tackled successfully
Ecological impacts: range shifts and niche impact
Range shift and migratory pattern impact
Impact on specialist species due to their small niche, whereas generalists can adapt and thrive in a variety of environments, specialists cannot adapt to use different habitats or food sources as quickly
Range shifts
- Current pattern is in northward direction - ~50% species migrating further north
- Generalist species show greater range shifts than specialist species
- Migrating species can be outcompeted by resident species filling the same niche
- Species that migrate can be outcompeted by resident species that already fill similar niches
- Range shifts that are faster or slower than expected show ecological challenges
Some species are adapting to warmer temperatures
Which species are moving northward?
*Roughly half of the world’s species are migrating, many northwards
*Habitat suitability is expanding in the north and is decreasing towards the south
*Some species in the south are adapting to the warmer temperatures, e.g., hemlock in California, USA
Once dry areas are now experiencing a higher level of precipitation. Hemlock is now moving down the mountain towards the warmer temperatures due to the higher levels of precipitation
Example: British Butterfly Species: Decline in non-migratory specialist butterfly species in the UK
*There are 46 non-migratory butterfly species in Britain
*¾ of these species have declined in numbers
*Likely due to a combination of habitat loss and effects of climate change
*Generalist species have been able to increase their distribution sites and ranges further north
Many of these butterfly species are restricted to local environments within Britain
A large proportion of the species that have declined are specialist species
Communities as a result are left with a reduced number of species, reducing biodiversity, as they will be dominated by mobile and widespread habitat generalist species
Changes in arctic species richness
*Overall, species richness is decreasing due to receding ice caps
*Some species have begun adapting their behaviours
- Killer whales can now move further north, allowing them to prey on narwhals and beluga whales
- Polar bears are beginning to build their dens on land instead of ice
Disruption of phenological patterns by climate change
Phenology is: The study of periodic life cycle events of an organism and how they are affected by their habitat and variation in climate
As global temperatures rise, phenological patterns are increasingly disrupted
Impact on ectotherms
Ectotherms are cold blooded, temp increases speed up maturation
*Growth and development fueled by metabolism –> increases exponentially with temperature
*Temperature size rule (TSR) –> ectotherms develop faster and mature to be smaller in warmer temperatures
^Additionally: Egg gender in sea turtles, tuatara and crocodilians is impacted by the heat of the sand they are buried
Marine mammal impact
*Marine mammals with high longevity and high site fidelity are more affected by climate change
*Leads to changes in migration patterns e.g. in Narwhals, impacted by receding ice
- Delay in autumn migration
- Correlation with Arctic Oscillation and changing sea ice dynamics
Migratory birds
Increasing temperatures linked to earlier arrival to breeding sites
Earlier start of breeding –> changes in abundance
Spring migration occurring earlier
More demand on resources in migratory zones
Recent phenological shifts of migratory birds at a
Mediterranean spring stopover site: Species wintering in
the Sahel advance passage more than tropical winterers
(Ivan Maggini et al. 2020)
https-J/d0i.org/IO.137100urnaI.pone.0239489
Plants
-On average, plants are flowering one day earlier per degree Celsius increase in average annual temperature
-Flowering times differ depending on elevation – earlier in low lands and later flowering has been observed in mid-elevation plants although less significant changes have been observed at high elevations
- Potential divergance of flowering times in small areas
- Can result in disruption in reproduction and pollination - impacting pollinator species and crop yields
Community-level phenological responses are occurring due to climate change
Measurement techniques in climate change ecology
Quantifying ecological impacts
Localised/remote monitoring
Localised measurement techniques
EDNA – DNA is extracted from the environment and compared to DNA libraries to identify presence of microbes or cryptic species e.g. used to test for quantities of zoo and phytoplankton in the North Sea found to be impacted by stratification
LiDAR- aircraft with GPS flying over an area measuring power of reflection to identify density of tree/shrub coverage e.g. useful to observe Arctic scrub dynamics identifying the changes in permafrost distribution over time
Camera traps and acoustic monitoring – to observe density of organisms in a specific area e.g. Mojave desert in California identified decrease in residency in areas further from woodlands, as woodlands are receding this is an important area for conservation research
Further info on EDNA
What is eDNA?
When an organism, say a fish, moves through the environment it’s constantly shedding bits of itself. A creature can shed anything from dead skin cells to mucus to faeces as it moves through its surroundings. The DNA in this organic matter is known as environmental DNA (eDNA). If someone tested a sample of the water, these pieces of DNA could indicate the recent presence of the fish, even if no fish is seen.
The benefits of studying eDNA
DNA can be collected from a whole range of environments, including water, soil and air. It allows researchers to build up a far more detailed understanding of the species that live in an environment than would be possible if we were to solely rely on identifying species by sight.
DNA also enables scientists to find and identify a whole host of small invertebrates and microorganisms that are plentiful in most environments, but very rarely surveyed due to their small size. These tiny creatures play a vital, if often overlooked, role in healthy environments, yet they are rarely counted due to their size, sheer diversity and the level of time and expertise required to identify them visually.
In fact, for some species groups, such as bacteria, the only realistic way to identify their presence is by searching for their DNA.
e.g. Tracking plankton changes in the UK
- Zooplankton metabolic rate and reproduction has increased in North Sea
- Whereas nutrient stratification has impacted phytoplankton causing decline over the last 6 decades
Further info on lidar - why and how it is used
Why LiDAR
Scientists often need to characterize vegetation over large regions to answer research questions at the ecosystem or regional scale. Therefore, we need tools that can estimate key characteristics over large areas because we don’t have the resources to measure each and every tree or shrub.
active remote sensing system that can be used to measure vegetation height across wide areas.
Remote sensing means that we aren’t actually physically measuring things with our hands. We are using sensors which capture information about a landscape and record things that we can use to estimate conditions and characteristics. To measure vegetation or other data across large areas, we need remote sensing methods that can take many measurements quickly, using automated sensors.
LiDAR, or light detection ranging (sometimes also referred to as active laser scanning) is one remote sensing method that can be used to map structure including vegetation height, density and other characteristics across a region. LiDAR directly measures the height and density of vegetation on the ground making it an ideal tool for scientists studying vegetation over large areas.
How Does LiDAR Work?
LiDAR is an active remote sensing system. An active system means that the system itself generates energy - in this case, light - to measure things on the ground. In a LiDAR system, light is emitted from a rapidly firing laser. You can imagine light quickly strobing from a laser light source. This light travels to the ground and reflects off of things like buildings and tree branches. The reflected light energy then returns to the LiDAR sensor where it is recorded.
A LiDAR system measures the time it takes for emitted light to travel to the ground and back. That time is used to calculate distance traveled. Distance traveled is then converted to elevation. These measurements are made using the key components of a lidar system including a GPS that identifies the X,Y,Z location of the light energy and an Inertial Measurement Unit (IMU) that provides the orientation of the plane in the sky.
How Light Energy Is Used to Measure Trees
Light energy is a collection of photons. As photon that make up light moves towards the ground, they hit objects such as branches on a tree. Some of the light reflects off of those objects and returns to the sensor. If the object is small, and there are gaps surrounding it that allow light to pass through, some light continues down towards the ground. Because some photons reflect off of things like branches but others continue down towards the ground, multiple reflections may be recorded from one pulse of light.
LiDAR waveforms
The distribution of energy that returns to the sensor creates what we call a waveform. The amount of energy that returned to the LiDAR sensor is known as “intensity”. The areas where more photons or more light energy returns to the sensor create peaks in the distribution of energy. Theses peaks in the waveform often represent objects on the ground like - a branch, a group of leaves or a building.
How Scientists Use LiDAR Data
*LiDAR data have also been used to derive information about vegetation structure includingCanopy Height
*Canopy Cover
*Leaf Area Index
*Vertical Forest Structure
*Species identification (if a less dense forests with high point density LiDAR)
https://www.bluefalconaerial.com/lidar-for-climate-change-research/
Advantages and limitations of Using LiDAR for Climate Change Research
Advantages of Using LiDAR for Climate Change Research
*LiDAR technology offers several benefits for climate change research, making it a powerful tool for studying and addressing the complex challenges posed by a changing climate:
*High-resolution data: LiDAR can generate detailed, three-dimensional maps with centimeter-level accuracy, allowing for precise measurements and assessments of environmental features and changes.
*Rapid data acquisition: LiDAR systems can cover large areas quickly and efficiently, providing up-to-date information for climate change monitoring and decision-making.
*Versatility and flexibility: LiDAR can be used to study various aspects of climate change, from deforestation to glacier dynamics, making it a versatile tool for a wide range of research applications.
*Integration with other data sources: LiDAR data can be combined with other remote sensing and in-situ data sources, such as satellite imagery and field measurements, to provide a comprehensive understanding of climate change impacts and processes.
Limitations and Challenges of LiDAR for Climate Change Research
Despite its many advantages, LiDAR technology also has some limitations and challenges that need to be considered when using it for climate change research:
Cost and Accessibility
Weather and Environmental Conditions
LiDAR data quality can be affected by atmospheric conditions such as clouds, fog, and rain, as well as the presence of smoke or dust particles in the air. Dense vegetation or rough terrain can also reduce the accuracy and coverage of LiDAR data, making it more challenging to obtain reliable information in certain environments.
Data Processing and Analysis
