Lichen has survived 18 months attached to the outside of the Int'l Space Station. If a microbe mutated while in space (as has happened already: astrobiology.com/2024/04/bact...) & was subsequently introduced back to Earth, should it be considered a non-native species? My answer would be yes. [1/🧵]

A warning by scientists. Owing to interactions among drivers, and the increasing spread of new & well-established alien species, "simple extrapolations from the impacts of invasive alien species observed today are likely to underestimate the magnitude of future impacts." phys.org/news/2024-06...

A common claim is that zebra mussels "clean" lakes. They can certainly clear the water column but also create conditions that reduce oxygen & promote toxic algal blooms: phys.org/news/2021-06... www.canr.msu.edu/news/telecou... cdnsciencepub.com/doi/10.1139/... www.greatlakesnow.org/2021/07/rese...

"When ecosystems fail, supply chains stall, costs spike, and financial stability is eroded. The World Economic Forum ranks biodiversity loss and extreme weather among the decade’s top global risks.  Yet, most companies leave nature out of their strategic plans." www.eco-business.com/opinion/busi...

It has been 5 yrs since Dan Simberloff & I developed an annotated 2nd edition of Charles Elton's famous 1958 monograph "The Ecology of invasions by Animals and Plants". We added 9 new chapter forewords, an introduction & a conclusion - all of which aimed to place Elton's ideas into a modern context.

There are no remote regions in a globalized world. The Antarctic region (ice-free peninsula, coastal waters, & surrounding islands) has been invaded by ~200 species of plants, animals, & microbes. Antarctica is connected to the world by global ship traffic. #bioinvasions www.pnas.org/doi/full/10....

A mentor's passion is inspiring. Months before he died, my former MSc supervisor Henry Reiswig said in a 2019 interview: "Every day [involves] a discovery of a small piece of the Earth's biodiversity puzzle that I strive to solve before I leave the endeavour to the next generation." bit.ly/2PgO0KM

Looking for a paleontological view of invasions? I recommend this paper: Stigall (2019) www.annualreviews.org/content/jour... Quote: "Species invasions—especially coordinated, interchange, and global invasions—have profoundly influenced the history of life and trajectory of evolution on Earth."

The Taxonomic Distinctiveness Hypothesis (Ricciardi & Atkinson 2004) predicts that invaders with no relatives in an area will have the largest ecological impacts. We found evidence of this for various aquatic systems. It is also supported by terrestrial studies. Eco-evolutionary context matters!

A case demonstrating why taxonomic accuracy is essential for conservation. A freshwater limpet in Japan was listed as an endangered native species. In 2018, genetic analysis revealed it was actually a nonnative species introduced from N. America. #bioinvasions link.springer.com/article/10.1...

"Look again", said the crow. "Perspective is everything." tinyurl.com/h9nrsta4

The term 'invasive' (wrt #bioinvasions) remains inconsistently applied. In the 1990s, legislators began defining 'invasive' with an impact criterion - to identify a subset of nonnative species to be managed. The definition I prefer is based exclusively on the process of spread, as explained below:

A major sign of the globalization of the Arctic is an increasing frequency of ship traffic over the past 30 yrs (see Pizzolato et al 2018, below). A more active Arctic shipping route is predicted to raise invasion risks throughout the northern hemisphere (see redpath-staff.mcgill.ca/ricciardi/Ri...)

Predicting an invader's impact is the holy grail of invasion ecology. The greatest challenge to prediction is context dependence. #bioinvasions My students & I often incorporate context dependence into experiments & models, to test the influence of key environmental variables. Some examples...🧵

#TansleyInsight: When the novelty wears off: enemy spillover drives #plant #invasion success Ian Dickie, Warwick Allen and Lauren Waller 👇 📖 nph.onlinelibrary.wiley.com/doi/10.1111/... #LatestIssue #PlantScience

Here are some of our lab's research findings on the ecology of the most invasive vertebrate in the Great Lakes-St Lawrence River system: the round goby.

Karenia cristata - a cryptogenic species and possibly an emerging global threat to coastal ecosystems, has now been found in southern Australia (once), South Africa (twice), and once near Newfoundland. www.science.org/content/arti...

“She never lingered in despair. She focused on what could be done.” time.com/7333425/jane...

Our new paper in Ecology Letters, led by Jan Divíšek, shows that non-invasive alien plant species that successfully establish within local plant communities tend to resemble the resident native species. In contrast, invasive alien species usually differ from native plants. doi.org/10.1111/ele....

The same rhetoric is used to dismiss extinctions ("extinction is natural; it's nothing new") & biological invasions ("species have always spread into new areas"). Yes, climate change, extinction, & invasion are natural processes - which now occur at extraordinary rates because of human activities.

New study reveals rats, not just humans, drove Easter Island's deforestation. The invasive rodents devastated palm forests through relentless seed predation. The real lesson is about unintended consequences when invasive species enter vulnerable island ecosystems medium.com/the-academic...

What would you share with an earlier version of yourself?

Quote: "We predict that the spread of toads to the Pilbara will cause an additional five mammals and four reptile species to be added to the threatened species list, and cause another species to be upgraded in threat status." www.nature.com/articles/s41...

In 2020 @wwf.panda.org identified the 100 global cities expected to suffer the greatest rise in water risk by 2050- home to at least 350 million people! We've already seen several megacities just days away from running dry. Here's a🧵 with eg's

New analysis suggests invasive Polynesian rats played a major role in Rapa Nui’s deforestation by destroying palm seeds, highlighting the combined impact of invasive species and human activity. doi.org/g99c8s

Mosquitoes were introduced to Hawaii on ships c. 1826. Non-native birds acted as a reservoir for the pathogen in lowland areas as native birds (which lacked immunity) became limited to high altitude forests. Climate change allowed mosquitoes to colonize higher elevations. www.cnn.com/science/hawa...

No obituary of James Watson is complete without acknowledging that his Nobel Prize-winning discovery was facilitated by the pioneering work of Dr. Rosalind Franklin - who established her own remarkable legacy in a tragically short time span.

Barred owls are an invasive species in western North America. Their westward spread was fueled by fire suppression, tree planting, and settlement, not by “natural expansion.” (Livezey 2009) 1/4

Brilliant story-telling and visuals, despite the tragic impacts of feral cats www.abc.net.au/news/2025-11...

New study from our lab: Feeding efficiency (trophic impact) of goldfish varies with combinations of thermal & salinity conditions typical of urban ponds in north temperate regions. Salinity enhances efficiency at temperatures below the thermal optimum of goldfish. link.springer.com/article/10.1...

As a grad student, I gave a talk at the 1994 International Zebra Mussel Conference (now called ICAIS) about a probable future N.Am. invasion by Limnoperna fortunei, the golden mussel. And in 1998 I wrote this warning: redpath-staff.mcgill.ca/ricciardi/Ri... The mussel was found in California in 2024

2024 essay on reconstructing the biogeography of the moose: "As moose populations multiply in the Southern Rocky Mountains, decision-makers are questioning whether the animals are endemic or invaders. Archaeology can offer answers—and potential solutions." www.sapiens.org/archaeology/...

The 2023 IPBES report on invasive alien species highlighted a global threat requiring multidisciplinary attention. In this 2021 paper, our team outlined four priority areas to advance invasion science in an era of rapid environmental change: cdnsciencepub.com/doi/full/10....

A 2017 article that rings more true today: "We can’t afford to dismiss the testimony of those with scientific and technical expertise. Like the airline pilots who we trust to fly our planes, scientists have knowledge and skills that many of us both lack and need." www.theguardian.com/commentisfre...

The head of a Thai NGO is being sued by an agribusiness giant for alleging the firm is linked to the outbreak of an invasive fish species in Thailand’s waterways. The blackchin tilapia has spread to at least 19 provinces, where it outcompetes other aquatic species and is disturbing ecosystems.

A comprehensive global assessment of the status & trends of alien species for major taxonomic groups. This is an outstanding product of the 2023 IPBES assessment on invasive species. onlinelibrary.wiley.com/doi/10.1111/...

After invasive predators (cats) are removed from an island, an endemic pigeon species recovers rapidly. Adult pigeon numbers rose from 111 to 966, and juvenile counts jumped from 9 to 189.

this scenario is exactly where an ethical framework would be important - something my colleague Gillian Crozier and I tried to address in our paper link.springer.com/article/10.1...

Congratulations to the 2025 recipient of the Volvo Prize, @naomioreskes.bsky.social! Naomi's work addresses vital issues such as why we need to trust science; a topic that becomes even more important with every new day. Read more here: www.environment-prize.com/laureates/na...

An invasive species of slithering, blood-sucking parasites in the Great Lakes has long been curbed by a small government program—one that may not survive the Trump Administration.