Have I Seen You Before? Counting A Species With Mark-Recapture
Tag Archives: population
Can Wind Farms Slow the Growth of Shorebird Populations?
Vulnerability of northern gannets to offshore wind farms; seasonal and sex-specific collision risk and demographic consequences (2020) Lane et al., Marine Environmental Research, https://doi.org/10.1016/j.marenvres.2020.105196
The Crux
A green on green conflict is what occurs when forms of renewable energy can have a potentially negative effect on the local environment. We see it in hydropower disrupting freshwater fish populations, or in the case of today’s paper, wind farms causing bird deaths. Marine shorebirds are often killed by wind turbines, yet it’s not totally clear to what extent population numbers are impacted by these deaths.
Additionally, whether wind farms are more dangerous to male or female, old or young birds could have a big impact on whether these bird deaths affect population numbers in the future. Today’s authors wanted to investigate this question, using a population of northern gannets off the coast of Scotland.
Read moreThe Numbers Game of Species Conservation
Deciding which species to conserve is hard enough, but deciding how many of a species is a viable goal is an entirely different matter (Image Credit: Frank Wouters, CC BY 2.0, Image Cropped)
When talking about species conservation, my concern is always around how many individuals should there be in a population of species. What should be our numeric goal in re-establishing a species? Should the endangered anoa become as many as their domestic relative, the water buffalo, of which there are at least 3 million individuals in Indonesia? How about the songbirds? Should each species be as abundant as the chicken?
Read more“Those Things Are Evil”: Prediction Intervals in Mixed Models
Suppose we study salamanders and want to predict body mass based on their body length. We also want to account for different access to food and differing levels of competition at each site we’ve collected our salamanders from. So we fit a linear model with a random effect for site as we only have samples from a subset of sites. (Want a refresher on random effects? We’ve got you covered.)
Read moreWorrying Trends in North America’s Bird Populations
Birds like this American tree sparrow are declining rapidly, shows a study which looks at huge declines in North American bird populations (Image Credit: Ryan Hodnett, CC BY-SA 4.0, Image Cropped)
Decline of the North American avifauna (2019) Rosenberg et al., Science, DOI: 10.1126/science.aaw1313
The Crux
When we talk about species loss, we generally focus on extinctions. Too often, when we start to rally around a species, it’s because there are a particularly low number of that species left. In many cases, they’ve often crossed a threshold, from which it’s impossible to pull them back from the brink of extinction.
Often this draws attention away from non-threatened species. Often that’s fine – they’re non-threatened right? But downward population trajectories in these species can still damage ecosystems by lessening the impact of their ecological function, lead to local (if not total) extinctions, and of course, leading them to eventually be threatened.
This week’s authors wanted to look at bird population declines in America, but from the perspective of total abundance, as opposed to a more species-specific view.
The Why and How of Genetic Diversity
Whilst cichlid fish might look incredibly diverse, they are actually all relatively genetically similar. So how do we define genetic diversity, and how do we conserve it? (Image Credit: Emir Kaan Okutan, Pexels Licence, Image Cropped)
Biodiversity has become an immensely popular buzzword over the last few decades. Yet the concept of genetic diversity has been less present in everyday ecological conversations. So today I want to go through why genetic diversity is important, how we define it, and why there is often controversy about its application in conservation science. Read more
It’s a Matter of Scale
Image Credit: Kevin Gill, CC BY 2.0, Image Cropped
No consistent effects of humans on animal genetic diversity worldwide (2020) Millette et al, Ecology Letters, https://doi.org/10.1111/ele.13394
The Crux
As a species, we humans have had enormous negative effects on the planet, and we have talked about many of these issues and how they relate to ecology on many separate occasions here on Ecology for the Masses (see here, here, and here). A key implication of these human-induced changes to our planet are that many organisms are threatened with extinction, which can be bad for us as well (looking at you insect apocalypse).
Having said all of that, a lot of the work that has been done in this area has focused on specific groups (like the charismatic koala). By doing so, we run the risk of not understanding the global pattern but instead draw conclusions based off of local patterns. While we sometimes must make these kind of generalizations, this is not always a good idea. For example, we cannot look at the health of animal populations in New York City and make statements about the entirety of all of the animal populations in North America. To get around that issue, today’s authors investigated, on a global scale, if humans were having a global impact on animal genetic diversity.
Read morePlaying the Ecological Long Game With Professor Jane Reid
The red-billed chough, subject on one of Jane’s long term studies of effects of the environmental on the size and structure of populations (Image Credit: Jean-Jacques Boujot, CC BY-SA 2.0, Image Cropped)
Our world is changing rapidly. Yet our perception of just how much it has changed is often dulled by our inability to compare what we see around us to what was around fifty years ago with enough clarity. This is one of the reasons that long-term scientific studies are so important. They give us a tangible assessment of just how much our world has changed, whether that be in the climate, how species have evolved, our how populations fluctuate.
Jane Reid is the new International Chair Professor at the Department of Biology at the Norwegian University of Science and Technology. Jane has spent years working with several long-term studies, some of them successful, others not so much. Sam Perrin and I spoke to Jane about the importance of long term studies in ecological science.
Why Warmer Winters Don’t Always Help Geese
Image Credit: MaxPixel, CC0 1.0, Image Cropped
Contrasting consequences of climate change for migratory geese: Predation, density dependence and carryover effects offset benefits of high-arctic warming (2019) Layton-Matthews et al., Global Change Biology, DOI: 10.1111/gcb.14773
The Crux
Most of us know that climate change will bring warmer, shorter winters to most parts of the world. For many species in areas like the Arctic, it would be easy to interpret this as a good thing – plants grow earlier, so animals get more food, right? Naturally it’s never that simple. Many herbivorous species have evolved in sync with climate cycles so that their reproduction peaks when food becomes available. If season start dates change, these species may not be able to change their own cycles in time. Additionally, what happens if populations of their predators suddenly boom?
Today’s authors wanted to know what role a warming climate played in the population fluctuations of migratory barnacle geese (Branta leucopsis).
Supermarket Science: How Consumer Choices Could Affect Ocean Biodiversity
Image Credit: AntTree, CC-BY-NC-ND 2.0
Can you help ease the global biodiversity crisis through the choices you make at your local fish market? A recent report by US-based nonprofit Eating with the Ecosystem suggests that the answer is a resounding “Yes!”
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Ecology for the Masses 