Hidden effects of habitat restoration on the persistence of pollination networks (2022) Gaiarsa & Bascompte, Ecology Letters, https://doi.org/10.1111/ele.14081
Image credit: dronepicr, CC BY 2.0, via Wikimedia Commons
It’s no secret that the world is undergoing a biodiversity crisis. This comes not only from climate change and human land use, but also invasive species – non-native species that cause harm to native ecosystems. Specifically, there are seven times more invasive species now than there were 75 years ago. Because of how many there are, and just how fragile ecosystems have become, it’s important to know what effects that invasive species have.
Ecological restoration (see Did You Know?) is one effective solution that can be used to mitigate the biodiversity crisis. Reestablishing native species can often help with this restoration, as does removing invasive species, but it usually requires human intervention. By removing these invasive species, the idea is that the native species will be released from competition and benefit from better access to necessary resources.
Yet to monitor invasive species removal, you need long-term data on population persistence, which is very difficult (logistically and financially) to collect. Understanding how the removal of invasive species benefits restoration requires not only measuring how such removal benefits ecosystem function, but also how it can benefit population persistence in the long term. Today’s authors wanted to understand how the removal of an invasive species benefited local community resilience.
The disruption of a keystone interaction erodes pollination and seed dispersal networks, Vitali et al., 2021 Ecology. https://doi.org/10.1002/ecy.3547
Image credit: Ennio Nasi, CC BY 4.0
Ecological communities are incredibly complex networks, made up of interactions between the species that reside in them. To properly understand how these interactions shape a community, researchers have to employ a variety of analytical methods and modelling approaches. This was something that I had to learn to appreciate in my work, because I always thought that studying ecology would involve a lot of time outdoors working with animals. While that does happen (and I spent months outside during my PhD), most of the ecological research I’m familiar with centers on math and statistics.
Using math and statistics to model ecological communities helps us to break down how various organisms are connected with one another. For example, keystone species are organisms that are connected to so many others within a given ecosystem such that any change to their populations will have consequences for the entire community. Understanding the processes that affect these keystone individuals (and all of the organisms linked to them) is vital to predicting how processes such as climate change and invasive species will affect natural communities in the future.
Today’s authors investigated how disruption of an important species interaction affected pollination and seed dispersal networks in Patagonia. A hummingbird species (Sephanoides sephaniodes) is the main pollinator for a mistletoe species (Tristerix corym-bosus), while the mistletoe provides the hummingbird with nectar in the winter. The colocolo opossum (Dromiciops gliroides) is a small marsupial that is vital for the mistletoe, as mistletoe seeds must pass through the opossum’s gut to trigger their germination. Additionally, the opossums defecate many seeds on branches in a “necklace” arrangement, which likely helps the mistletoe to parasitize their plant hosts. These three species are tightly connected to one another, and any reduction in abundance for one species may affect the other two, and even destroy the entire food web.
Image Credit: Ted, CC BY-SA 2.0, Image Cropped
Invader-pollinator paradox: Invasive goldenrods benefit from large-size pollinators (2021) Moroń, et al., Diversity and Distributions, https://doi.org/10.1111/ddi.13221
A plant that invades a new part of the world can’t necessarily bring its regular pollinators along with it. So it stands to reason that plants who successfully invade a new area receives pollination from native pollinators. Seems pretty straightforward, right?
Plant pollinators come in all shapes and sizes. There are the stereotypical insects such as butterflies and bees, birds, mammals… and lizards.
Yup, you read that right. They’re not super common, but there are a few species of lizards and geckos who like going against the grain and choose to visit flowers for their daily meal, with about five species being known to act as pollinators. This makes pollination by reptilian visitors an extremely rare and understudied pollination syndrome. Hopefully at some point in the future we will know what the perfect floral bouquet for a lizard looks like!
Tanya Strydom is a PhD student at the Université de Montréal, mostly focusing on how we can use machine learning and artificial intelligence in ecology. Current research interests include (but are not limited to) predicting ecological networks, the role species traits and scale in ecological networks, general computer (and maths) geekiness, and a (seemingly) ever growing list of side projects. Tweets (sometimes related to actual science) can be found @TanyaS_08.
An empirical attack tolerance test alters the structure and species richness of plant–pollinator networks (2020) Biella et al., Functional Ecology, https://doi.org/10.1111/1365-2435.13642
Image Credit: Adamantios, CC BY-SA 3.0, Image Cropped
Put simply, ecosystem function is the process that control how nutrients, energy, and organic matter move through an environment. Think about a forest. You have small plants that are eaten by small animals, small animals that are eaten by larger animals, and those larger animals are eaten by even larger animals. When those animals die, they are broken down and consumed by scavengers, fungi, and bacteria. These processes result in a continuous flow of nutrients and energy through the ecosystem. However, if one link (organism) in this chain breaks (goes extinct), the ecosystem could lose its function, and other species that depend on this cycle could go extinct as well.
The way in which a given ecosystem reacts to or recovers from any negative impact that it sustains is key to understanding how ecosystems function. Classically, this is tested with attack tolerance tests, in which all species on a given trophic level are removed and the ecosystem is then monitored to see how/if it maintains its function. In studies of plant-pollinator networks, this is usually modeled with computers, but studies which use natural systems are lacking. Today’s authors wanted to use a natural plant-pollinator system to see what happens.
Image Credit: Pete, CC BY-NC 2.0
Increased reproductive success through parasitoid release at a range margin: Implications for range shifts induced by climate change (2020) MacKay, Gross, & Ryder, Journal of Biogeography, https://doi.org/10.1111/jbi.13795
Predicting the response of organisms to climate change is a challenge for ecologists and wildlife managers alike. Fortunately, some responses are common enough that it is still possible to make fairly accurate predictions about them without too much information. One common response is that of the range shift, whereby a population of organisms facing some alteration (eg. climate change) in their current habitat, making it unfavorable, begin to move to another location. This allows them to track favorable environmental conditions and possibly mitigate any negative effects of climate change.
Sounds easy, right? Just pack it all up and move when things get hard? Well, for some organisms it may be that simple (looking at you, birds), but for others (like trees) it is significantly harder to do so. Trees (and other plants) are limited in that they depend on other organisms or things like wind to help disperse their seeds. Making things even more difficult are plant species that depend on specific pollinators, and in order for a successful range shift to happen trees AND their pollinators have to make the move. Today’s authors wanted to study how relationships between trees and their pollinators changed at the leading edge of a range shift, allowing them to understand how and why trees succeed during a range shift.
Dr. Erica McAlister of the British Natural History Museum recently released The Secret Life of Flies, an exploration of the more fascinating side of the fly (Image Credit: Erica McAlister, CC BY-SA 2.0, Image Cropped)
The Norwegian ForBio conference occurs once a year, and brings together a large collection of biosystematics experts from the Nordic countries. Biosystematics being a bit outside my field, it’s not something I’d generally attended, however this year it was 250m away from my office, so I considered attending. But what tipped me over the edge was the presence of Dr. Erica McAlister of the British Natural History Museum, who in late 2017 published The Secret Life of Flies, a brilliant expose on one of nature’s traditionally less sympathetic taxa.
Erica’s talk was fascinating, replete with stories of lost artifacts, mosquito sex and David Attenborough. Afterwards, I got the chance to sit down and chat with Erica about everything from the problem with honeybees, to the beauty of mosquitoes to issues with a certain Jeff Goldblum character.