Why are monarch butterflies declining in the West?

Elizabeth Crone, Tufts University

Live blogging from UC Berkeley Wildlife Seminar, January 25th 2019. (Still my favorite University. Still my favorite seminar.)

Monarch butterflies had the lowest population sizes ever in 2018! Shocking news on Thursday January 17, 2019 in the San Francisco Chronicle. What is going on??? Here is the link: https://www.sfchronicle.com/news/article/California-s-most-famous-butterfly-nearing-13539657.php#photo-16782648

Elizabeth Crone from Tufts University came to UC Berkeley today and gave a talk at the Wildlife Seminar about the three following points:

  1. How much has the whole population declined?
  2. Why are they declining?
  3. What can we do about it?

There is a global insect Armageddon. Art Shapiro at UC Davis says: ‘No. We don’t know why.’

Western Monarch butterfly populations are much smaller and less studied than the ones at the East Coast. They spend several generations at California coasts and move then inland towards Rocky Mountains. Monarch butterflies are just awesome because their migrations include several generations. While the grandparents might have been born at the coast, their grandgrandchildren decide to fly somewhere else. The same cycle repeats many generations later.

Elizabeth’s talk was about the population in the West only!

In Central California there are volunteers, CITIZEN SCIENTISTS, who count butterflies every year around Thanksgiving. In 1997, there was a very high count, then only smaller numbers. Had numbers before 1997 been consistently higher? There were no citizen scientist projects back then. Elizabeth had to collate data from different research groups. She found quite a lot but nothing was standardized. Everybody had used different approaches. Hence, Elizabeth had to apply some statistical models to account for all this variation. She did MARSS modeling and analyzed a very long time series. This model assumes that monarchs function as a single large population in the west, with a single growth rate. For each site she estimated a rate of proportionality compared to the total population. MARSS also allows to include an observation error. –> Estimate of historic abundance. 1980s millions of butterflies, 2000 only thousands. Something happened in the 90s. Population decline is ~7% per year.

In 2018 counts dropped again. We have never had anything close to this low. Yet, it might just be ordinary fluctuations in the environment. If we loose a few hundred butterflies in a population of several millions, the population will persist. However, if we loose a few hundreds in a population of a few thousands, this population might eventually go extinct due to the extinction vortex. So Elizabeth applied for emergency funding from the NSF. Is anybody looking for an awesome postdoc position???

Picture taken from https://xerces.org/monarchs/

What caused decrease: Climate (temperature, precipitation)? Everybody always thinks first it is climate change. Pesticides. Habitat loss. Overwintering habitats along the coast have become smaller due to housing development and dryland farming. How do we know which factors really drove the population decline? Don’t do linear modeling with so many correlated variables. Instead: PLSR: Partial Least Square Regression. This analysis can handle a large set of variables. Retains uncertainty about which variable is correlated with outcome. Similar to PCA. Relative importance of different variables for 1st and 2nd components (axes). What did the model spit out? Summary: Land development, glyphosate, and nicotinoids all correlated negatively with butterfly numbers. With regard to the drop in 2018, it could be attributed to the cold and wet months of February and March. They had been bad for butterfly recruitment.

Not just climate change – land use matters. And use of pesticides by everybody, farmers and hobby gardeners. This is a large landscape scale problem. Not just butterflies. Many other insects are suffering from the same problem.

During the questioning session in the end: Some monarchs don’t migrate. They sit on perennial milk weed their whole life. These populations are common in Southern California and Mexico. In Central and Northern California, populations are migratory. Don’t buy perennial milkweed in the store and plant them in the garden. They might invite butterflies to become stationary and then infected by parasites. Indeed, stationary populations have higher parasite loads! Buy endemic milkweed to support Western butterflies and plant them early in the season. Thanks.

And a little side note: Elizabeth is an awesome presenter. She must be a really great teacher. Thanks for entertaining us.

#istmobiome workshop in Panamá

I am writing a personal blog post about my most recent Panama trip. A more scientific summary will follow soon through RCN’s website about evolution in changing seas.

I flew to Bocas del Toro on November 27th to finalize our workshop preparations with the two co-organizers Matthieu Leray and Jarrod Scott at STRI (Smithsonian Tropical Research Institute). We took care of the last logistical preparations and rehearsed our presentations. Ben Yuen from the Petersen lab in Vienna also arrived early and helped us with the workshop preparations. He also joined me on my hunt for lucinid clams.

Jarrod @metacrobe, myself @M_helvetiae, and Matt @Matt_Leray

Ben and I digging for clams at the STRI dock in Bocas del Toro

Maggie Sogin @MaggieSogin is giving us mental support. And it helped!

Ben and I searched all over the Bocas del Toro archipelago for Codakia, Ctena and Clathrolucina species. These are clams that live in seagrass. They have bacterial symbionts  in their gills that are able to oxidize sulfide. The clam filters water that is rich in sulfur through its gills. The endosymbiont bacteria are able to use these compounds to fix carbon. This carbon is then used as nutrients for its host – the clam. Seagrass beds are very rich in sulfides and lucinid clams have evolved a three-way symbiosis with seagrass and their bacterial endosymbionts. Because of the lack of oxygen in coastal marine sediments, dense seagrass meadows produce sulfide-rich sediments by trapping organic matter that is later decomposed by sulfate-reducing bacteria. The lucinid-symbiont holobiont removes toxic sulfide from the sediment, and the seagrass roots provide oxygen to the bivalve-symbiont system. 

Thalassia seagrass habitat

Lucinid clams checking out what’s going on?!

Funded by the Gordon and Betty Moore foundation, I am studying how this symbiosis evolved after the rise of the isthmus of Panama. I am also looking at patch effects and comparing local populations on both sides of the isthmus. My project is based on population genetic and coalescent theory. I am collaborating with ecologists in Vienna – the Petersen lab, and at Stony Brook University – the Peterson lab!

Ben and I found a valuable set of clams before, during and after the workshop!

Snorkeling and digging…

Two Ctena imbricatula individuals!

And more digging. We need bigger sample sizes…

A very happy digger!

We are being stalked by Jonathan’s underwater drone!

Trident, one of the top ten drones on the market: http://www.top10drone.com/best-underwater-drones/

The workshop itself took place from December 3rd until the 8th. Matt, Jarrod and I prepared the whole program which mostly consisted of questions that the participants would answer in groups, followed by plenary discussions. We also sprinkled in a few lightning talks to learn more about each other’s research. And we organized two excursions. One was a snorkeling trip to familiarize everybody with the different marine habitats and ecosystems at Bocas del Toro. The other one was of palaeontological nature where we went to an island with plenty of fossils. We brought a few hammers and collection bags. Everybody would spread out and collect fossils. Most of these fossils are more than 3.5 Million years old. This is older than the isthmus, hence these fossils lived in the big ocean that was later split into Pacific Ocean and Caribbean Sea. This excursion was led by Aaron O’Dea. It was my personal highlight. I got very emotional. Happy. Standing there and embracing one of the most awesome natural Darwinian experiments by nature.

Lots of fun in class…

… and in the field!!! Wall of fossils on the right and the isthmus straight ahead.

The raise of the isthmus of Panama is not only the playground of our research, it also affected the evolution of us humans. I learned at the Biomuseo in Panama City that the closure of the isthmus gave birth to the Gulf Stream. The Gulf Stream affected the climate all over the planet. It was after the final closure that humans migrated out of Africa. There is evidence that the Gulf Stream made Northern Africa drier and savannahs developed where previously had been forests. This coincides with humans walking more upright. I never thought about the relationship of this small strip of land and human migration out of Africa. Sure, it makes sense that this land bridge would allow species to cross from North America to South America and would ultimately affect biodiversity on land. But would it also affect global climate and indirectly facilitate human evolution?

All our #istmobiome workshop participants. A diverse sample of contemporary Homo sapiens.

What we are studying right now is how the rise of the isthmus affected marine life and symbioses in particular. We are working on many different marine host systems including urchins, porcelain crabs, snapping shrimp, reef fish and lucinid clams. If you want to read more about the workshop and what we discussed, check out our istmobiome website: https://istmobiome.net/

Now we are writing a white paper about what we discussed at the workshop. Stay tuned!

I would like to shout out a big thank you to all participants, the Moore foundation for giving us money and sending Jon Kaye – a very congenial person; and the Smithsonian Tropical Research Institute (STRI) for financing and facilitating this workshop. Last but not least, I want to thank Ben for keeping me sane.

Full of good spirits

And Jonathan for mentoring me. Jonathan is such a good person that there are no English words for him. Hence, I tried to introduce him in Swiss German… Check out our live tweets from the workshop under the hashtag #istmobiome!


After the workshop and collecting more clams, my family came and spent a few days with me in the jungle of isla Bastimento. I love Panama. And I am trying to share this with my closest ones.

Precious cargo




Department of destruction

Five weeks ago, we landed in Zürich. Back home in Switzerland. Since then I went through many emotions and memories. Constantly inhaling everything around me. Privilege. Mostly privilege. Swiss people don’t know how privileged they are. I have been breathing cristal clean air and drinking the most pure and tasty water since months. I have talked to researchers being funded by millions of Swiss taxpayer dollars (Franken, actually). I have looked at sparsely populated paradise valleys. I have touched the most happy and friendly cows in the world.

Lots of fieldwork on brown trout in Graubünden with Roland Tomaschett, graduate student Victor Ammann and many invaluable helpers from my family

Giachen explores his home

Trip to Vienna with my mom to meet Jillian Petersen

Ennio growing up

Family time with Mayra and Miguel

Gelateria di Berna Nostalgia

Ennio creating mosaics with the kids at Lake Geneva during my collaboration with the Engel lab at UNIL

Quality family time at my brother Emanuel’s farm

Linnea playing in front of EAWAG, The Swiss Federal Institute of Aquatic Science and Technology where I met professors Jakob Brodersen and Ole Seehausen

Now I am back in California. We were looking forward to returning to heaven. Instead, we realized that the apocalypse is here. Right now.

Today: Smoke in the city

Fires in July: The County Fire west towards Lake Berryessa has burned over 22,000 acres without containment on Sunday, July 1, 2018 in Napa County.

Donny and I made a list. I accomplished 40 important tasks in Switzerland. I worked without a break. Now I am looking out of the window and wonder about life. Davis is covered in smoke. Inside. Outside. Everywhere. Climate change is here. Right now. We are all in it. Privileged people and less privileged people as well. Everybody. It is absolutely surreal for me to see people walking through the smoke with face masks. In the most beautiful state in the world. It is burning down.

UC Davis closed two days ago. Jonathan Eisen, my sponsor and mentor at UC Davis fought for it. The health risks are simply too big. Public schools were open until today. Mostly because so many parents work and can’t afford to keep their kids at home. However, the air quality became so bad today that all schools are closed now. We are not sure if we will stay in Davis over the weekend.

It seems like we are all working for the department of destruction. By the way, did you know that there is a Department of Destruction? We learned about it after we forgot our passports in the airplane from Paris to Zürich. We had been flying from San Francisco to Paris. The kids were super nice, but Jacoby decided not to sleep. So, we stayed up with him. Doing things. After immigration and transfer in Paris, we fell asleep on the plane to Switzerland. All four of us. Like a coma. We actually fell asleep before the plane departed from Paris. Somebody had to wake us up in Zürich. When we rushed out of the plane, we forgot the passports on the plane. When I called later and asked at Air France, the cleaning personnel, the airport police; we were told that our passport were found. Somebody brought them to the airport police. The Swiss one was destroyed immediately according to Swiss law. The Americans were sent to the embassy and were going to be destroyed within 21 days. At the Department of Destruction. This is us.

Family dinners

We started this new tradition of having dinner together. This was just not our thing. However, it is wonderful if it is just Donny, Linnea, Jacoby and I.

The rules are: Everybody has to say something about their day. Everybody has to listen to the others talk. In the end everybody has to ask a question about the world.

Linnea hit off the first couple of nights by asking:

  • Are all stars suns?
  • How many days since you were five years old?
  • How old is God?
  • Would you have enough time to count to one hundred trillions before you die if you spoke it out loud?
  • Why are you sometimes angry at me and sometimes you feel sorry for the same thing?

Internship and Master thesis project of David Zeugin

This post is written by David Zeugin, University of Lausanne

My project with Laetitia was about the decline of a European grayling (Thymallus thymallus) population in Lake Thun, Switzerland. We looked at the effects of inbreeding on offspring survival. To manage this population, juveniles are bred each year in a hatchery from a stock of captive fish and released into the wild. However, breeding fish in a hatchery leads inevitably to inbreeding. We investigated the effects of this inbreeding by comparing reproduction success of wild fish and captive ones simultaneously in a climate chamber at the university. During the course of their development, we measured embryo survival, time until hatching and sizes of larvae. Additionally, we tried to develop a gynogenesis protocol.

Getting the fish (grayling) in Kandersteg, BE.

Gynogenesis allows the creation of artificial diploid homozygote offspring from the haploid genetic material in the eggs of the mother. Eggs are fertilized with inactivated sperm and then exposed to heat shock or radiation to trigger cell division. Eggs and sperm from wild fish and hatchery stock were used for this protocol. The effects of inbreeding at different levels; i.e., crossing wild individuals vs. crossing hatchery stock fish vs. crossing a female with itself was measured by stressing the resulting embryos with three fish pathogens, Pseudomonas fluorescens, Aeromonas salmonicida and Aeromonas sobria.

Inactivating the sperm.

Inside the UV box.

We had a very low success rate of gynogenesis. The number of viable diploid offspring for each female was so low that we could not statistically compare their performance to the other grayling embryos and larvae. The number of viable embryos was relatively high but they all died before hatching. However, grayling embryos coming from parents that had been produced and raised in hatcheries reacted with a higher mortality and earlier hatching compared to the offspring of wild fish when presented to both A. salmoncida and A. sobria

fertilized eggs

Most of the gynogens are dying.

Head and eyes become visible.

The supervision of Laetitia in this project helped me to take initiatives, to be rigorous in my experimental design and conduct, and to develop my communication skills. I directly profited from her large knowledge on the subject and appreciated that Laetitia was supervising my work and at the same time giving me the opportunity to develop my own hypothesis on the project.

I am now a Ph.D. candidate in the Ionta lab and work on neuroscience. I am studying the neural basis of visuo-motor control and how they interact in the human brain.  https://iontalab.org

In the climate chamber

lots of data

freshly hatched

Living with Wolves in California

Wildlife seminar by Kent Laudon

Es ist wieder einmal an der Zeit einen Blog auf Deutsch zu erfassen. Es geht um Wölfe. Kent Laudon arbeitet für die Behörden. Er ist sozusagen ein Amtsbiologe. Er hat sich auf Wölfe spezialisiert.

Der Raum ist voll. Ich habe ihn noch nie so vollgestopft gesehen. Absolut soziopolitisch. Kalifornien hat seit ein paar Jahren ein Wolfsrudel. Genau wie Graubünden.

Im Vergleich zu Graubünden ist die Geschichte hier etwas anders verlaufen. Die Europäer haben Nutztiere mitgebracht und alle natürlichen Raubtiere ausgerottet. Die Wölfe in Kalifornien wurden ganz ausgerottet, Bären nur teilweise. Seit 1996 (etwa 100 Jahre später) wandern Wölfe wieder ein aus Kanada.

Im Vortrag geht es vor allem und Sichtungen von Wölfen. Alle Wölfe hier tragen Halsbänder mit Sendern. Das Amt hier weiss genau wo die Wölfe sind. Laudon fährt mit seinem riesigen Pick-up truck durch den Wald, sein Mountain Bike im Kofferraum und sucht Signale seiner Wölfe. Amt für Jagd und Fischerei auf Amerikanisch. Wenn die Wölfe sich in die Wildnis zurückziehen steigen die Biologen auf Pferde um. Freiwillige Mitarbeiter hat es genug. Sogar ehemalige Förster und aktive Jäger.

Ich nehme nicht viel mit vom Vortrag ausser ein paar schönen Erinnerungen, Fotos und Videos. Was mich erstaunt ist wie weit die Wölfe wandern jeden Tag. Die Karte zeigt Idaho, Oregon und Kalifornien und der Wolf läuft darin herum wie auf einem Fussballfeld. Schnell einmal 100km at Tag.

Auch sehr spannend sind die Videoaufnahmen im Juli 2015 wo am gleichen Tag Wölfe und Bären zu sehen sind.

Wölfe laufen gerne auf Strassen und Wanderwegen. Hier in Kalifornien benutzen sie auch Flüsse, die im Sommer austrocknen als Korridore.

Die Mehrheit der Bevölkerung in Kalifornien lebt immer noch im 1924 als die Wölfe erfolgreich ausgerottet wurden. Kent sieht seinen Job vor allem darin, mit Leuten zu reden und aufzuklären. Was fehlt im grossen Teil der Bevölkerung sind Grundkenntnisse der Ökologie ihrer eigenen Umwelt. Als Beispiel dazu zeigt Kent wie sich die Populationsdichte der Wölfe an die der Hirsche anpasst. Wenn es viele Hirsche hat, dann vermehren sich die Wölfe. Dann essen sie viele Hirsche und deren Population bricht zusammen. Ein Jahr später bricht die Wolfpopulation ein und die Hirsche können sich wieder erholen (Daten aus Wisconsin).

Für die mit Grundkenntnissen auf Englisch habe ich hier noch ein paar sehr spannende Unterlagen. Und das hier. Adrian Treves konnte sehr schön aufzeigen und quantiativ bestätigen, dass der kontrollierte Abschuss von Wölfen durch die Regierung dem Ruf des Wolfes schadet. Wenn die Bevölkerung sieht dass die Regierung eine geschützte Art abschiesst, dann empfinden sie den Wolf nicht mehr als schützenswert. In einigen Gebieten hat das sogar dazu geführt, dass Jagdfrevel zugenommen hat.

Als ich Kent darauf angesprochen habe, hat er ganz aggressiv reagiert. Wie immer. Wölfe = Emotionen. Er meinte, es sei die Aufgabe der Regierung, die Wolfspopulation zu kontrollieren und regulieren. Er sagt das, nachdem er gerade das Raubtier-Beutetiere Schema gezeigt hat.

Ich habe mich hier reingesetzt für eine Pause von einem langen Tag im Büro. Es war erfrischend. Ich habe viel an unsere Calanda Wölfe gedacht. Vor ein paar Tagen habe ich nach langer Zeit wieder einmal eine Nachricht von einem Freund aus Graubünden erhalten. Das hat mich riesig gefreut. Es haben mich also noch nicht alle vergessen daheim. Passt gut auf eure Wölfe auf! Gell Ueli! Liebe Grüsse.

Einmal um die Sonne mit den Calanda Wölfen

Getting ready for my second Panama Trip

Today David Coil and I are flying to Panama for a our first official sample collection. I feel like I am fully prepared, including all necessary vaccinations, a travel laptop from Jonathan that I just set up fresh, an extra phone with a Panamanian SIM card and local number, money in small bills, having informed my bank about my credit card, lots of different kinds of collection tubes, DNA extraction kits, petri dishes, culturing media for bacteria, anaerobic incubation chambers, diving equipment, Linnea’s dissection scope, insect repellent, treated clothes against mosquitoes and ticks, instant coffee, and most importantly, photo equipment.

Honestly, I did not sleep much the last couple of nights. However, the collection schedule is penciled down, my future research plans have taken some shape and in theory, I am fully prepared.

David and I will keep you entertained with our traveling blog at: https://istmobiome.net/

Keith Bouma-Gregson’s exit talk

What you must know before reading this blog is that here at Berkeley most talks are great. You could go to a seminar every single day and learn new things and hear brilliant people talking. This also applies to graduate students’ exit talks. The last one I went to was by Tristan Nunez. See here.

Today it is Keith Bouma-Gregson. He did a PhD in Mary Power’s lab in Integrative Biology at UC Berkeley. He will be moving on to work with Jill Banfield now. Check her out. She is awesome. http://nanogeoscience.berkeley.edu/

Mary Power’s introduction:

Keith worked on a variety of projects on food web ecology, aquatic ecology, cyanobacterial genomics (mostly Phormidium: a toxic cyanobacterium), public health and citizen science. He also worked a lot on the Eel river restoration project. http://www.eelriverrecovery.org. Keith involved local people so that they would learn what the problems are with cyanobacteria and the toxins that they produce.

There is a funny, dark, little story. Somebody found a human skull in a river in Humboldt County. The police wanted to use their sniffing dogs to find the rest of the body but they did not know whether they could let their dogs into the water because of the toxic cyanobacteria. So Keith went there and checked it for them. He could confirm that the waters were safe. So whenever these detectives will have similar problems they know now who they have to contact…

Full hearts, clear eyes on the eel can’t lose. FULL HEARTS, CLEAR EYES ON THE EEL CAN’T LOSE. (you have to scream it out loud).

OK. Now Keith will start his talk:

Background: Water systems in California have been affected heavily by human alterations like pollution, damming, or the addition of fertilizers. The climate in California is mediterranean, the highest water levels occur at the wrong time for agriculture. Hence, humans built dams and reservoirs for saving it. Consequently, there is not enough water for the ecosystem when it needs it for its highest productivity. Due to the huge anthropogenic impacts on Californian waters, cyanobacterial blooms have increased. These bacteria will bloom and become the most common taxa in the environment. Legrand et al. showed in the journal Toxins in 2017 that cyanobacterial blooms are increasing recently (shown in Lake Zurich, Switzerland). Cyanobacteria produce toxins that are harmful to the mammalian liver and nerves. Not all strains contain the genes to produce these toxins.

Keith’s thesis: was based on the Eel River system. UC Berkeley has a field station in the middle of this system, the Angelo Coast Range Reserve. By the way, I did a large part of my fieldwork on O. mykiss in this reserve. Keith monitored the Eel River for cyanobacteria. He wanted to find out where, when and who is there. Together with Professor Kudela at UC Santa Cruz, Keith built Solid Phase Absporption Toxin Trackers (SPATTs) to measure toxins in the water. The toxin Anatoxin-a showed very high levels throughout the watershed. The highest levels were measured in August when the river temperatures were highest. At this point, Keith did not know which taxa were producing these toxins.

Keith went ahead and identified all cyanobacteria he could find in the system. He described mostly Anabaena spp. (Nostocales) and Phormidium spp. (Oscillatoriales). To do this, Keith collected green mats in the field, brought them to the lab and measured their toxin concentrations. He could find Anatoxin-a and Microcystin toxins in all mats. The levels were so high that they would kill a dog and maybe even be toxic to a cow. Moreover, Anabaena spp. were associated with low flowing water. It builds clumps and they get stuck in eddies and pools of the river. This could be a health risk for humans swimming in the river. Keith performed an experiment to investigate when cyanobacteria float and when they sink to the ground in the natural river. He found that they remain buoyant for days in a natural light regime (Bouma-Gregson et al. in Harmful Algae 2017).

He learned the following:

  • Cyanotoxins are produced by benthic Anabaena and Phormidium.
  • Anatoxin-a is frequent and shows high concentrations.
  • Cyanobacteria float at high concentrations in the river during summer and could represent a potential health risk.

As a next step, Keith performed genome resolved metagenomics. He collected cyanobacteria at 22 different sites across the Eel River system, extracted their DNA and assembled them into contigs to get a draft metagenome. Then he binned out individual genomes into draft genomes. With these samples he would first describe the bacterial composition and then look for the Anatoxin-a synthesis operon. He could find this operon in 7 samples. Then he linked the presence/absence of this operon to bacterial community composition. He found that samples with this operon clustered together. This was mostly driven by the presence of Burkholderiales.

Keith also identified the main energy pathways in his microbial mats. Most bacteria in his samples had genes for carbon oxidation. He did not find any bacteria that use methane, hydrogen or sulfate to gain energy. However, he found a few bacteria that metabolize Urease. Many of his bacteria contained a gene that codes for a transporter that can transport phosphate inside their bodies. Moreover, they also have a pathway where they excrete an enzyme into their environment that binds inorganic phosphorus and transforms it to phosphate which they then can import back into their cells. It seems that these bacteria are super effective at scavenging phosphorus, even if its concentrations are low. This could be an explanation why Phormidium dominates in the Eel river system that has high organic nitrogen levels and low phosphorus levels.

Keith ended his talk with the following statement: Cyanobacteria have been around in our environment ‘forever’ so the goal should not be to eradicate them but to learn more about them and how to deal with them.

This is Keith. He is also active on twitter as @K_BoumaGregson