Thermal trouble in the tropics

Tim Perez, James Stroud and Ken Feeley published a new Perspectives article in Science Magazine entitled “Thermal  Trouble in the Tropics”.  The article explains why tropical species are at extra risk of extinction under climate change compared to their temperate counterparts.  They also discuss the need for additional studies of tropical plant species and their climatic tolerances. A copy of the article is available HERE.

Ken Feeley discussed the article during a radio interview with John Batchelor.  A podcast of the interview is available to download or listen to HERE.



Priority effects in a changing climate

A new publication from the Feeley Lab in Frontiers in Ecology and Evolution addresses the importance of priority effects on species range shift. The publication is a comment to a paper published in Nature by Alexander et al (2015).

Commentary: Novel competitors shape species´ responses to climate change

Belen Fadrique and  Kenneth Feeley

There is a growing appreciation of the need to understand the effects of climate change on species interactions and how changes in interactions can influence the ability of species to persist in the face of climate change (Araújo and Luoto, 2007; Thuiller et al., 2008; Svenning et al., 2014). However, empirical or experimental studies investigating species interactions under climate change remain extremely scarce. Alexander et al. (2015) use experimental transplants of European alpine plant species and communities to provide valuable insight into some of the novel competitive interactions that may emerge as species migrate upslope to keep pace with rising temperatures. More specifically, they look at performance of plant species under simulated upslope migrations into preexisting higher-elevation plant communities as well as the performance of plant species that fail to migrate and find themselves competing with new suites of species migrating into their community from below. This is a useful approximation of some of the scenarios that are already being created by the unequal responses of species to climate and the creation of novel communities.

One limitation of the study by Alexander et al. (2015) is the omission of the earliest phases of establishment when processes such as dispersal and germination are crucial in the encroachment of initial populations of migrant species into the new locations (Hampe, 2011). In particular, the experimental set up fails to account for one of the potentially most important drivers of community assembly—priority effects. Priority effects refer to the observation that early colonists will often inhibit, or alternatively facilitate, the establishment of subsequent colonizers (Connell and Slatyer, 1977).

Keep on reading HERE.

OTS leftovers: Does leaf pH influence herbivory?

My research focuses on how species have adapted to environmental variation and how these adaptations influence species’ niche breadths and geographic distributions. Although IUntitled focus on tropical plants, and insect herbivores are a substantial biotic selection pressure, herbivory is not a topic I actively pursued until I participated in an OTS course last summer. On my OTS course I was able to investigate an array of topics from plant defense to plant-mediated tri-trophic interactions, all of which are documented in our 2015 OTS coursebookOf all the projects I participated in, the last project of the course remains my favorite because it has provoked new questions, some of which have informed my thesis research.

In this last project, my classmate and I were following-up a previous study in which we investigated the ability of leaf pH to predict herbivory in plants. Literature suggested that low pH values deter herbivores in the sub-arctic where ungulates, not insects, are the dominant herbivores. Consequently, the influence of leaf pH on herbivory in tropical to sub-tropical regions where insects are the dominant herbivores is unclear. In our first project, my classmate and I found no effect of leaf pH on standing herbivore damage in the 5 Piper species we measured. For our follow-up project we were interested in determining the sources of variation that may have influenced leaf pH, and thus, the results of our previous study. Ultimately, we decided to investigate diurnal and ontogenic changes in leaf pH for two Piper species. 


Figure 1: Ontogenic changes in leaf pH of P. multiplinervum & P. hispidum

Interestingly, our immature leaves exhibited the lowest pH values (Fig 1), and immature leaves have previously been shown to be the most palatable to insect herbivores. Compared to mature leaves, immature leaves tend to receive more insect herbivory because they are softer, are higher in nutrients, but also produce more chemical defense compounds. Therefore, leaf acidity may be correlated with leaf age and linked to chemical defenses that deter herbivores. If so, leaf pH could be an easily-measured trait used to understand the susceptibility of plants to insect herbivory.

In addition to ontogeny, leaves also exhibited diurnal changes in their chemistry (Fig 2). We found that both immature and mature leaves that were measured in the morning (~9am) had lower pHs than leaves measured in the the afternoon (~4pm). These diurnal fluctuations may have resulted from changes in carbonic acid and cytoplasmic proton gradients throughout the day. However, given the potential relationship of pH to chemical defenses, it is easy to speculate that some chemical defenses could fluctuate throughout the day in addition to ontogenic phase. 


Figure 2: Diurnal changes in leaf pH of P. multiplinervum & P. hispidum

Since our first study did not properly measure herbivore damage, the effect of pH on insect herbivory remains an unanswered question. The observations from our follow-up study indicate pH is probably correlated with ontogeny, which has been shown to influence the production of chemical defenses that deter herbivory. pH was also observed to fluctuate diurnally, and may indicate diurnal changes in herbivore deterrence.

What I think is exciting about these results is that if pH does influence herbivory, insects may feed upon leaves according to temporal differences in leaf chemistry. In turn, these short-term temporal feeding preferences could promote co-existence of insect species, which greatly outnumber plant species, and are likely to overlap in diet-breadth. There are many unanswered questions that this project has induced that warrant further investigation before any concrete conclusions can be made about the influence of pH on insect herbivory. 

My uncharacteristic foray into plant-insect interactions has led me to a new understanding of niche-breadth and coexistence theories through concepts such as the storage effect that incorporate temporal niche partitioning – a topic of great relevance to my thesis. Moreover, my newfound interest in herbivory highlights the benefit of stepping outside the territory of your own research in order to gain a better understanding of it. 

Now that I am in Florida, where Pipers are introduced and rare,  I’ve been
gathering information on the native species Psychotria nervosa to address some of the questions I developed while on my OTS course. I’m currently collecting and identifying insects that feed on P. nervosa, and have already quantified ontogenic changes in leaf nutrients. As my course-load dwindles and the resources at the International Center for Tropical Botany 
become available, I hope to dedicate more time to understanding how leaf chemistry influences insect herbivory in the sub-tropics as a side-project…so stay tuned.


Me (Tim Perez) happily collecting Piper cenocladum at La Selva Biological Station, Costa Rica.

P.E.O. ayudando a la educación superior de las mujeres

(see below for English version)

En la mayoría de los casos, el camino hasta llegar a los estudios de postgrado, y especialmente si es un postgrado en ecología tropical, no es barato.

Después de mis estudios de licenciatura, me encontré realizando actividades que definitivamente me iban a ayudar a desarrollar mis habilidades, enriquecer mi experiencia y mi curriculum, pero también a empobrecer mi cuenta bancaria. Fui voluntaria en laboratorios, en expediciones de campo, realicé prácticas en el otro lado del mundo y me apunté a varios cursos de inglés para tener varios certificados. Solía decir que todas estas actividades eran INVERSIONES. Cuando comencé mi doctorado pensé que todas esas inversiones por fin se veían recompensadas. Y sí, era verdad, estaba en un buen grupo de investigación, estudiando lo que yo quería. Sin embargo, muy pronto me di cuenta de que el doctorado era otra inversión. Tuve que hacer malabares para poder pagar las tasas, la renta, la comida, el seguro, el coche y todo lo necesario para empezar una vida en Miami.

Afortunadamente, mi compañera de laboratorio Catherine Bravo me animó a solicitar la International Peace Scholarship, ofrecida por la hermandad P.E.O. (Philanthropic Educational Organization). Esta beca apoya a mujeres internacionales que realizan estudios de postgrado en los Estados Unidos y Canada. Durante este año académico, P.E.O. me ha proporcionado apoyo para pagar las tasas y algún otro gasto, lo que ha hecho mi vida mucho más fácil y amena.

P.E.O. fue fundada en 1869 por siete estudiantes de Iowa Wesleyan College en Mount Pleasant, Iowa. El objetivo era promover oportunidades de educación para mujeres. La hermandad ha crecido y ahora está presente en los 50 estados de Estados Unidos y en seis provincias de Canadá. Hay más de 250.000 miembros de P.E.O. en el mundo. Más de 90.000 mujeres se han beneficiado de P.E.O. a través de becas, préstamos, premios, proyectos especiales y Cottey College.

Recientemente, tuve el honor de acudir a una comida en conmemoración de la fundación de P.E.O. por siete mujeres valientes, que desafiaron el mundo de su tiempo. Conocí a mujeres increíbles de diferentes capítulos de Broward County, Florida. Me mostraron un increíble entusiasmo por mi investigación, mis objetivos y el impacto que yo misma y otras mujeres podemos tener en la sociedad.

Fue una experiencia increíble y me gustaría agradecer a P.E.O. no solo por la beca, que es muy útil, sino por el apoyo emocional y social que me proporcionan.

P.E.O., helping women pursue higher education

In many cases, the path to arrive to Graduate school, and especially Graduate school in Tropical Ecology, is not cheap.

After completing my undergraduate degree, which already required a fair amount of money, I found myself performing different activities that were definitely helping the development of my skills, the enrichment of my experience and my resume, but also the depletion of my bank account. I volunteered in labs, in field expeditions, I had internships in different parts of the world and I enrolled in several English courses. I used to say (for myself and the judging world) that all of those activities were INVESTMENTS. When I got into the PhD program I thought that, finally, all of those investments would be acknowledged. Yes, they were; I got into a good lab doing what I want to do.  However, I soon realized that Grad school was one more investment. I was financially juggling to pay the fees, the rent, the food, the insurance and the car; everything to start a life in Miami.

Fortunately, my lab mate Catherine Bravo encouraged me to apply for the International Peace Scholarship offered by the sorority P.E.O. (Philanthropic Educational Organization). This scholarship supports international women doing their graduate studies in the United States and Canada. During this past academic year, they have provided me support to pay my fees and some extra expenses which has made my life a lot easier and enjoyable.

P.E.O. was founded in 1869, by seven students at Iowa Wesleyan College in Mount Pleasant, Iowa. The goal was to promote educational opportunities for women. The sorority has grown and now it is present in the 50 states and 6 Canadian provinces. There are more than 250,000 members of P.E.O. around the world.  More than 90,000 women have benefited from P.E.O.´s educational grants, loans, awards, special projects and stewardship of Cottey College.

I recently had the honor of attending a luncheon to commemorate the foundation of P.E.O. by the seven brave women who challenged the world of their time. I met incredible women from different chapters in Broward County, Florida. They showed an incredible enthusiasm about my research, my goals and about the impact that myself and other women can have on society.

It was certainly a great experience and I want to sincerely thank P.E.O., not only for the funding which is incredibly helpful, but for the emotional and social support that they provide me.




Invasive Cuban Lizard in Bermuda

The work of upwithclimate team member, James Stroud, is featured on the Discovery Channel’s Discovery News website.  To read the article, follow this link.  The Discovery News article is based on a press release by Evelyn Perez and the FIU NEWS, copied below.


Invasive lizard takes up residence in Bermuda

FIU biology student James Stroud has observed a non-native species of lizard in Bermuda, a potential problem for the island’s critically endangered Bermuda skink.

A two-year conservation project studying the island’s lizard populations led to the discovery of the Cuban brown anole, a species once rumored to inhabit the North Atlantic island, but was never verified until now.

“The Cuban brown anole most likely reached Bermuda by human transport,” said Stroud, a Ph.D. student in the Kenneth Feeley Lab. “These lizards hitch rides between ports as unintended stowaways amongst cargo, usually in nursery plants and building materials. Although further research is needed to confirm it, this route of introduction seems likely.”

The introduction of the Cuban anole could pose difficulties for the endangered Bermuda skink, the island’s only native lizard species. Also known as a rock lizard, the skink is listed as critically endangered in the International Union for Conservation of Nature’s (IUCN’s) Red List, the world’s authority on the conservation status of plant and animal species. According to the researchers, Cuban brown anoles excel at thriving outside of their native geographical area. The lizards can live in a variety of natural and human-made habitats, and feed on a variety of prey, potentially putting them at an advantage to other lizard species who might not be as tolerant.

“We have discovered that the Cuban brown anole does not yet overlap its distribution with the Bermuda skink,” Stroud said. “Therefore, the potential effects of the non-native brown anole on the native Bermuda skink are currently unknown. This topic forms part of our ongoing research interests in Bermuda.”

After surveying all of Bermuda, Stroud found populations of the Cuban lizard at all life stages indicating they are thriving in the central part of the island. He also found the established Jamaican anole continues to be found all over the island, but the Antiguan anole has significantly expanded into areas where the Barbadian lizards live. The discovery was made alongside former FIU doctoral student Sean Giery and Bermuda’s Department of Conservation Services.

Originating in Cuba and the Bahamas, the Cuban brown anole is one of the most widespread lizards outside of its native area with large populations found from Florida to Texas, California, Hawaii, Costa Rica, Singapore and Taiwan. Cuban brown anoles can be found in urban environments including downtown Miami and natural environments such as the Everglades. Anoles are very diverse group of lizards and about 372 species are currently known to exist.

Stroud recently traveled to Costa Rica where he conducted the first-ever study of the Cuban brown anole’s ecology and distribution in the Central American country. He is devoting his doctoral research to studying the evolution, interactions and community patterns of Anolis lizards in the tropics.

The Cuban brown anole was recently confirmed to live in Bermuda by FIU biology Ph.D. student James Stroud. Photo by James Stroud

Cuban Brown anole in Bermuda.  Photo by J Stroud.

Time to start walking the walk

Yesterday I served as an expert panelist for a discussion of climate change and conservation with about 50-60 middle school students.  Overall it was a very positive experience, but…

Included with the event was a ‘breakfast’.  Here is a picture of our ‘breakfast’:


A conservationist’s breakfast?


Even looking past the fact that a donut does not constitute a real breakfast, we can see several obvious problems.  Namely, The donuts were served individually on plastic plates and coffee was served in styrofoam cups.  The only other drinking option was bottled water.  And there was no recycling bin in sight so all plastic plates and bottles went straight the trash.

How hypocritical are we that we can lead a discussion with children about the dangers of climate change and the need for them all to be responsible consumers, while at the same time we sit there drinking out of styrofoam cups?  What type of example are we setting?

Similarly, last month I spoke at a major fundraising function to help entice donors into supporting a new tropical conservation center at my university.  And guess what we all ate for dinner as we sat around discussing tropical deforestation?  Beef!  We were not even given a choice – beef for all!  And to go along with our plates of deforestation, we were all given various pieces of literature, none of which was printed on recycled or sustainably-sourced paper.

Again, how hypocritical can we be?