Image Credit: Manfred Antranias Zimmer, Pixabay licence, Image Cropped
Invasion of freshwater ecosystems is promoted by network connectivity to hotspots of human activity (2019) Chapman et al., Global Ecology and Biogeography, https://doi.org/10.1111/geb.13051
The spread of invasive species throughout freshwater ecosystems is a topic we’ve looked at before on Ecology for the Masses. In a previous paper breakdown we talked about how recreational is heavily responsible for the presence of non-native fish at a European scale.
Our paper this week takes a more local approach. Can we predict the presence of non-native birds, invertebrates and fish by looking at the presence of human activity, and where that human activity is present?
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.
When migrating, animals like the great white pelican have to walk the fine line between saving time and saving energy. (Image Credit: Ray in Manila, CC BY 2.0, Image Cropped).
Landscape-dependent time versus energy optimisations in pelicans migrating through a large ecological barrier (2019) Efrat et al., Functional Ecology, https://dx.doi.org/10.1111/1365-2435.13426
We have all seen the amazing scenes in nature documentaries of the great seasonal migrations undertaken by many different species on this planet. By migrating between two different habitats, migrating animals are thought to maximize both how many resources they have access to, and to minimize their exposure to harsh environmental conditions.
Despite these benefits gained by migrating animals, there are risks associated with these seasonal, long-distance travel events. Migrating animals, like the great white pelican (Pelecanus onocrotalus), have to decide what is better: traveling for a shorter distance or using less energy by taking a less strenuous – but longer – path. Today’s authors tracked the great white pelican during its seasonal migration over the Sahara to study how these birds made decisions about their travel.
Animals depend on consumable energy to live, and that energy can come from a variety of places. If the energy that animals get from their food varies in quality depending on where the animals get their food, what does this mean for birds like the Eastern Phoebe (Sayornis phoebe) that consumes both terrestrial and aquatic food? (Image Credit: Andrew Cannizzaro, CC BY 2.0, Image Cropped).
Aquatic and terrestrial resources are not nutritionally reciprocal for consumers (2019) Twining et al., Functional Ecology, https://dx.doi.org/10.1111/1365-2435.13401
In the natural world, ecological subsidies, or the influx of sustenance from one habitat type to another, connect a variety of environments. While research has been conducted on this topic in the past, most of it has dealt with the quantity of energy moving between habitats, but not the quality of the resource itself.
When one habitat (such as an aquatic habitat) is rich in a specific resource that is hard to find in other habitats, subsidies of these resources play a unique role by providing animals and plants with food or energy that they could otherwise not get. The authors of today’s paper wanted to investigate if subsidies from aquatic habitats and terrestrial habitats contain the same amount of that hard to find, valuable resource: highly unsaturated omega-3 fatty acids (HUFAs). Read more
This Peruvian warbling-antbird must walk a fine line between being different enough from its competitors to reproduce successfully, while staying similar enough to be able to recognize and outcompete the same competitors (Image Credit: Hector Bottai, Image Cropped, CC BY-SA 4.0).
Range-wide spatial mapping reveals convergent character displacement
of bird song (2019) Kirschel et al., Proc B, https://dx.doi.org/10.1098/rspb.2019.0443
In nature, many different organisms can be found in a single location, and sometimes those organisms are closely related to one another. When this happens, classical evolutionary theory predicts that these closely related species should differ in some ways, so as to differentiate members of their own species from others and avoid the costs associated with breeding with a mate that will not produce any viable offspring. This is called character displacement, and there are many examples of this in nature where two different species may be very similar when they live in different places (allopatry), but when they live in the same place (sympatry) they will differ in appearance, behavior, or the exact part of the local habitat that they live in (see Niche Partioning below).
A specific form of character displacement, called agonistic character displacement, occurs when traits or behaviors associated with competition differ between closely related species living in the same area. This is thought to reduce the costs of wasting energy on competing with an organism that you don’t really “compete” with. Agonistic character displacement can, however, result in greater similarity of traits when similar species live together, but previous studies in this area have not accounted for other causes of this similarity. Today’s authors wanted to do just that. Read more
Species like this red-crowned crane perform yearly migrations, but how do they weigh up the costs and benefits? (Image Credit: Alistair Rae, CC BY-SA 2.0, Image Cropped)
Where the wild birds go: explaining the differences in migratory destinations across terrestrial bird species (2018) Somveille, Manica & Rodrigues. Ecography, 42, p. 225-236.
Migratory birds make up a huge chunk of the world’s bird life, yet there are still a lot of gaps in our knowledge concerning why they migrate to the areas they do. There’s a variety of potential benefits to migration, from remaining within a comfortable temperature range or a preferred habitat, to gaining access to areas that have a surplus in resources, to escaping competition with resident species. However, migration also results in increased mortality due to the amount of energy it takes. This week’s study tried to analyse the drivers of migration, and what trade-offs were made between migration’s potential benefits and costs.