A role for the local environment in driving species-specific parasitism in a multi-host parasite system (2022) Hasik & Siepielski, Freshwater Biology, https://doi.org/10.1111/fwb.13961
Image credit: Adam Hasik, image cropped
Parasites are an ever-present part of every ecological community on Earth, yet there are some species that harbor more parasites than others. In systems where parasitism is density-dependent, meaning parasitism increases with host density, the most common/numerous species will harbor the greatest amount of parasites. Yet there are also cases of species-specificity, whereby parasites specifically target a single host species. In other host-parasite systems, local-adaption plays a role in parasitism dynamics, whereby parasites are better at attacking their local hosts than they are attacking foreign hosts and/or hosts are better at defending themselves from local parasites than foreign parasites.
With all of these different factors affecting how host-parasite systems operate, it is important to identify when and if each one is operating within specific ecological communities. This is especially necessary when ecological communities are comprised of multiple host species and multiple parasite species, all of which can/do interact with one another.
To investigate the above factors, we first conducted a survey of parasitism in damselflies (Enallagma spp.) and their water mite parasites (Arrenurus spp.). From there, we then carried out to field experiments to understand why parasitism operates the way it does within this system.
Image credit: Nick Hobgood, CC BY-SA 3.0, Image Cropped
If you’ve ever seen the movie Finding Nemo, you might’ve also heard the fun tidbit that Nemo’s dad, Marlin, should have become a female when Nemo’s mother Coral died. As strange as it may sound, this is true for many species of fish on earth. Every clownfish community has one female in charge (the only female in the community), and that female only mates with one male, the largest male in the community. The rest of the community is made up of smaller, immature, non-breeding males. When the female dies, the breeding male will become the new female, and the largest of the immature males will take the role of the breeding male. Simple enough, right?
The Sumatran tiger, which is different from other subspecies of tiger for reasons (Image Credit: Bernard Spragg, CC0 1.0)
We’re only 3 months in, but 2022 has been a hell of a year for species-related controversy. Grolar and pizzly bears have come roaring into public consciousness, researchers proclaimed that the T-Rex we know and love is actually three different species, and soon-to-be minted Doctor Yi-Kai Tea has been sinking and raising some truly glorious fish species like nobody’s business (we call this taxonomic ha-wrasse-ment).
With the classification calamities flying thick and fast, it’s easy to wonder exactly what it is about naming a species that is so damn hard. So let’s have a quick runthrough of what a species is, why taxonomy is so damn complicated, and why it even matters.
Today we associate lions with Africa, but they used to be widespread around the northern hemisphere (Image Credit: MLbay, Pixabay licence, Image Cropped)
While I continuously hear my little one’s nursery rhyme about a certain stuff going round and round, I think, what else moves round and round in my field? Species!
They move around as they are looking for a mate, food, to avoid cold weather, the list goes on. They occupy a reasonable range that can be handled by their bodily functions, and either stay in that range or move when the environment changes. A species’ historical movement is one of the most important aspects of its natural history.
This article was first published in late 2018 (Image Credit: Mallee Catchment Management Authority, CC BY-SA 4.0, Image Cropped)
When a food source provides almost half a planet with protein, you can expect the people who deliver that food source to play an important role in society. Fishing is no exception. Any country that has a marine or freshwater ecosystem in close proximity will have a fishing community, and that community can play a variety of roles, from something as simple as putting food on people’s tables to campaigning heavily to keep your country from joining the EU.
So it makes sense that fishers should have access to good fish science, at every level. If you’re a multi-million-dollar corporation, you need to know how fish stocks will respond to certain catch levels over a sustained period. If you’re a local or specialised fishing community, you need to know how available your catch will be in five years given temperature increases. And if you’re one person on a boat in a river, you might want to know how best to treat an over- or under-sized fish to ensure it survives being released.
It follows, then, that there should be open communication between fish scientists and fishers. At this year’s Australian Society of Fish Biology conference, I asked a variety of delegates a simple question: Is there open communication?
Invasive freshwater fish (Leuciscus leuciscus) acts as a sink for a parasite of native brown trout Salmo trutta (2020) Tierney et al. Biological Invasions. https://doi.org/10.1007/s10530-020-02253-1
From house cats to cane toads, invasive species are one of the biggest threats worldwide to native plants and wildlife, second only to habitat destruction. There are a few different definitions of an invasive species, but two consistent tenets are a) that they are a living organism spreading and forming new populations outside of their native range and b) causing some kind of damage to the native ecosystem, economy or human health. As humans move around the globe with increasing ease (these last two months aside), the spreading of invasive species is increasingly common in our globalised world.
The spread of invasive species creates new ecological interactions between native and invasive species that can impact how our native ecosystems function, including disease dynamics. One key set of interactions that can be completely changed by the introduction of the invader are that of parasites and their hosts. If development and transmission of native parasites is different in invasive hosts compared to their usual native hosts, the parasite dynamics of the whole system can be altered.
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 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.
Mapping co-benefits for carbon storage and biodiversity to inform conservation policy and action (2019) Soto-Navarro et al., Philosophical Transactions of the Royal Society B, https://doi.org/10.1098/rstb.2019.0128
With the world under so many anthropogenic pressures simultaneously, trying to come up with management solutions for different issues can be a problem. Climate change and biodiversity are a great example. Storing carbon is a great way to reduce the effects of climate change, and increasing the range of forests worldwide is a great way to increase carbon storage. Yet the sort of forests that store carbon most efficiently are often poor at promoting biodiversity. They are largely made up of very similar trees, while forests that include brush, scrubs, and other layers often store less carbon, but house more biodiverse communities.
As such, finding areas that are prime specimens for a) storing carbon and b) biodiversity conservation are incredibly important, so that managers at every level (from park rangers right up to the Intergovernmental Panel on Climate Change) can know where interests overlap, and adjust plans accordingly.
Image Credit: Lazy Daisie, CC BY-SA 3.0, Image Cropped
There’s a certain age you hit when you just can’t name your third favourite mammal anymore. I often quietly pray that the day my kid stops asking weird questions about animal snot never comes, but I know it’s probably not far off. That eagerness to learn at a young age, especially about animals, is what ecologist Sammy Mason has managed to tap into over the last two years of her PhD.
Image Credit: Dmitry Teslya, CC BY 2.0, Image Cropped
Species-area relationships on small islands differ among plant growth forms (2020) Schrader et al., Global Ecology and Biogeography, https://doi.org/10.1111/geb.13056
We’ve talked a lot about Island Biogeography Theory (IBT) in the last couple of weeks. One of the key tenets, established way back in the 60s, is that as an island’s area decreases, its species richness tends to as well. Yet since IBT was conceptualised, there have been a number of amendments made to it. The Small Island Effect (SIE) is one of them.
SIE essentially means that below a certain threshold (called a ‘breakpoint’), species stop obeying that species richness to area relationship. This week’s researchers wanted to test whether that breakpoint was different between species groups, and whether the species area relationship changed below that breakpoint, or simply disappeared.