Author Archives: Julia Ramsauer

Radar vs. Optical: Optimising Satellite Use in Land Cover Classification

An optical image of Kliuchevskoi volcano on the left, with a radar image on the left (Image credit: Michigan Tech Volcanology, Image Cropped)

Improving the accuracy of land cover classification in cloud persistent areas using optical and radar satellite image time series (2020), Lopes et al., Methods in Ecology and Evolution, https://doi.org/10.1111/2041-210X.13359

The Crux

Most ecologist has at some point run across or used a land cover map in their career. Whether it’s used for figuring out the canopy diversity of a forest, or figuring out which habitat a species is using, land cover maps are incredibly useful tools for everyone from conservationists to architects. But have you ever wondered how they are produced?

Until recently, land cover maps were created using either images from optical satellites or images from radar satellites with a coarse to medium spatial resolution (check out the Did You Know Section for more details, or the image above for an example). Combined with classification algorithms, land cover maps can be created automatically. That makes it sound simple, but the final output depends greatly on the quality and amount of images you use for the classification. Since 2014, the Copernicus Programme has made satellite imaginary freely available at high spatial and temporal spatial resolution. Due to this, optical and radar images can be combined more efficiently to produce land cover classification maps with enhanced accuracy. This is especially useful in tropical and boreal areas, as optical images often don’t show the entire landscape due to persistent cloud over.

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Adaptation of Forests to Climate Change: Is It Possible?

Urbión Model Forest in Castilla y León, Spain (Image Credit: Julia Ramsauer)

In a world in which it’s still tough to convince many people that climate change is a very real phenomena, figuring out ways to tackle climate change is an even more difficult problem to wrap our heads around. In general, there are two strategies we can use: (1) mitigation (reducing the accumulation of greenhouse gases in the atmosphere) and, (2) adaptation (reducing the vulnerability of societies and ecosystems facing the impacts of climate change).

In my last piece (linked here), I wrote about the effects of climate change on forests. But what about the reverse, and their potential to mitigate climate change? Forests are crucial for climate change mitigation – they literally suck carbon out of the atmosphere. At the same time, forest adaptation will be necessary to avoid degradation of forest ecosystems due to a changing climate: an extremely complex task.

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Introduced Species Might Restore Ecological Functions Lost During The Ice Age

Image Credit: hbieser, Pixabay Licence, Image Cropped

Introduced herbivores restore Late Pleistocene ecological functions (2020) Lundgren et al., PNAS, https://doi.org/10.1073/pnas.1915769117

The Crux

The fauna of the Pleistocene (also known as the Ice Age) was not that dissimilar to the communities of animals which inhabit our planet now. However, many more large land mammals inhabited all kinds of ecosystems. By the end of the Pleistocene, many of them were extinct, mainly due to climate change impacts (glaciers got larger and restricted their ragne) and prehistoric human impacts like over-hunting, habitat alteration, and introduction of new diseases. The decline of large-bodied herbivores in the Late Pleistocene (LP from here on) led to many ecological changes including reduced nutrient cycling and dispersal, reduced primary productivity, increased wildfire frequency and intensity, and altered vegetation structure. These changes have become our norm.

Scientists usually study species introduction under the premise that they are ecologically novel. However, the introduction of large herbivores has been found to drive changes in the environment, potentially restoring or introducing novel ecological functions similar to pre-extinction Late Pleistocene conditions. This week’s researchers wanted to investigate what sort of role introduced mammals played in restoring ecological interactions by investigating their functional similarity with LP species.

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The Impact of Climate Change on European Forests

Province of Lleida, Catalonia, Spain (Image Credit: Julia Ramsauer, CC BY 2.0, Image Cropped)

As carbon emissions rise globally, finding ways to reduce emissions and store carbon are coming to the forefront of modern science. Forests are huge carbon stores thanks to the copious amount of photosynthesis they conduct. As climate change increases temperatures, trees become a very important tool in the fight against rising emissions. One study even described forest restoration overwhelmingly more powerful than all other proposed climate change solutions. You might think: “So let’s go and plant trees!” Unfortunately, it’s not so easy.

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COP25: A Short Review and On-Site Experiences

Image Credit: Julia Ramsauer, CC BY 2.0

Last Sunday, the UN Climate Change Conference (COP25) in Madrid came to an end. It was a summit that marked the end of a year in which climate change has transformed into a climate emergency and in which society has woken up to the urgency of the situation. Taking into account the pressure from global demonstrations of groups like Fridays for Future and Extinction Rebellion, and the fact that even scientists have further challenged world leaders on the urgent need to act by striking in September, hopes for the outcomes of this year’s climate summit were big. For a couple of days, I was in Madrid to participate in the part of the COP25 that was open to the public and to march with thousands of others in the biggest demonstration ever held in Spain.

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