The diversity and phylogenetic community structure of ants along a Costa Rican elevational gradient

Submitted by editor on 5 August 2014.

M. Alex Smith (salex [at] uoguelph [dot] ca; and on Twitter: @Alex_Smith_Ants)


[note – each photo legend below has a link to the full size image on Picasa included as a comment]


We’re very happy that our paper on the phylogenetic diversity and community structure of ants along an elevational gradient in Northwestern Costa Rica comes out in the August edition of Ecography (Smith et al. 2014). Understanding the evolutionary and ecological implications of elevation gradients, especially amongst hyperdiverse insects in the tropics, is important in an era of unprecedented population decline (Dirzo, et al. 2014) and species extinction (Pimm et al. 2014). We’re also pleased our article has a home in Ecography – a journal with a long history of publishing work about, the patterns and causes of elevational diversity gradients. We feel that our new work is both a good example of a new approach integrating phylogenetic community ecology and DNA barcoding, as well as documenting the initiation of a long-term inventory of ants in protected Neotropical area. It has been a very exciting period to plan, collect, analyse and consider these results – in particular since the work occurs within one of the most important protected areas in Latin America, the Area de Conservacion Guanacaste (ACG).  We are all very grateful for the support of the ACG parataxonomist team and the ACG staff in protecting this area, and in enabling this research.

Figure 1: [A1] view from cloud forest sampling site near the top of Volcan Cacao, ACG. Photo by Alex Smith.

The ACG, is a 165 000 hectare national park in northwestern Costa Rica. It extends from 6 km out in the Pacific to 2,000 m at the top Volcan Rincon de la Vieja and down into the Atlantic lowland rain forest.  A UNESCO World Heritage Site, the ACG is home to more than 375 000 species of plants and animals (an estimated 2.4% of the world's biodiversity) and has grown dramatically from a 10K acre national park (formalised in 1971) to a global example of tropical biodiversity conservation, dependent upon, and inserted within, the development and economy of the local people. 

Figure 2[A2] : Just down slope from the Bosque Arenales at 1000 m, Volcan Cacao. Photo by Alex Smith.

If you are interested in more information on the ACG, please visit the Guanacaste Dry Forest Fund (GDFCF) website. At the bottom of that page you'll find a button to donate to the ACG.  "Every penny donated to GDFCF goes to forest purchase to expand ACG" – a worthwhile investment. The ACG is host to numerous ongoing projects in the ACG – you can explore a blog covering some of this on the “Investigadores ACG” website.


I have been working with ACG insect diversity since 2004 (Fernandez-Triana, et al. 2014, Fernández-Triana, et al. 2014, Smith, et al. 2012, Smith, et al. 2006, Smith, et al. 2007, Smith, et al. 2008) in collaboration with Dan Janzen and Winnie Hallwachs (in fact – the opportunity to work with these two was the principal reason behind my decision to move to the University of Guelph). The ACG is, without a doubt, one of my favourite places in the world – and a place that I feel privileged to be able to work. 

Figure 3: [A3] Smith with Harry Ramirez Castillo, Dunia Gricela Garcia and Jose Manuel Pereira Espinoza who regularly check and change the Malaise traps on Volcan Cacao. Photo: Alex Smith.

Climate models for northwestern Costa Rica predict that high elevation regions will receive significantly less precipitation during the dry season, while the frequency of dry events during the rainy season will increase (Karmalkar, et al. 2008) a result of changing rainfall patterns and a rising cloud base. Learning the degree to which evolutionary history is distributed within these forests is an important part of understanding the effect of the impending upheaval posed by this drying. In 2008, I initiated a research project investigating the community changes associated with elevation across three volcanos within the ACG – our publication in Ecography marks the first contribution of this program. We found evidence of significant phylogenetic clustering within the highest elevation cloud forest sites and surprisingly narrow elevational range of each species.  Our results suggest that climate change, experienced as warming, altered rainfall and rising cloud base will likely result in dramatic changes in the location and composition of biodiversity on these mountains. The structure and composition of the hyperdiverse communities present at any one elevation is extremely vulnerable to a changing climate.


To document the ant communities along these Neotropical volcanoes I use a standardized collection protocol to help me understand the ant species diversity at each locality. Watch movie here.


The ants I collect are databased, mounted, photographed and DNA barcoded in an attempt to measure community change with elevation, with volcano and with time.  "Time" is particularly important, as the peaks of the volcanoes are drier and warmer than they have been - and I am very interested in documenting and testing who is arriving and what happens upon these arrivals! At each site I record the habitat where I work in high-resolution detail using a GigaPan robot.


[140219 - Costa Rica, Area de Conservacion Guanacaste (ACG), Volcan Cacao, 1,500m]  


Figure 4: Fish-eye view of a GigaPan of cloud forest on Volcan Cacao. Photo by Alex Smith.

This remarkable piece of equipment consists of three technological developments: 1) A robotic camera mount for capturing very high-resolution panoramic images using a standard digital camera; 2) software for constructing very high-resolution gigapixel panoramas; and 3) a website for exploring, sharing and commenting on gigapixel panoramas and the detail users will discover within them.  You are encouraged to explore a gallery of nearly 100 high-resolution GigaPans from within the ACG - from sea level to 1500 m up each of the three volcanos. From high-resolution habitat-scale imagery to microscopic resolution, I have also used a digital field microscope to capture ant activity in the field. I have been charmed and amazed at what this tool adds to my field work.  With each collection trip, the videos are moved directly to YouTube – currently there are more than 200 videos – have a look!

Figure 5: Sampling in the cloud forest near the top of Volcan Cacao. Photo by Alex Smith.

One important aspect to our research is that the publication, analyses, data and collections are all accessible. The paper is open access, as are the data associated with the analyses, the DNA data, the fieldnotes,  audio recordings, GigaPans and videos are all available for examination and re-testing. 


Movie here.


Long-term standardized arthropod sampling through continuous, elevational gradients is critically important to testing macroecological hypotheses such as the relative importance of habitat filtering/selection or the competitive exclusion of closely related species.  Unfortunately, in the contemporary funding environment, gathering the funds necessary for long-term monitoring in the neotropics is a challenge.  We are very grateful to the agencies that fund our work in the ACG: a Discovery Grant from the Natural Sciences and Engineering Research Council of Canada (NSERC), a Leaders Opportunity Fund from the Canada Foundation for Innovation (CFI), Systematics Research Fund, by a generous donation from Anne Lambert, NSF DEB 0515699 (to DHJ & WH), Guanacaste Dry Forest Conservation Fund and the Wege Foundation. Finally, we all emphatically and gratefully acknowledge the support of the ACG parataxonomist team the staff of the Area de Conservación de Guanacaste in protecting this area, and in enabling this research.


[130328 - Costa Rica, Area de Conservacion de Guanacaste (ACG), Volcan Cacao, 1200m]

Gigapan here.




Dirzo, R. et al. 2014. Defaunation in the Anthropocene. - Science 345: 401-406.

Fernandez-Triana, J. L. et al. 2014. Review of the neotropical genus Prasmodon Hymenoptera, Braconidae, Microgastrinae), with emphasis on species from Area de Conservación Guanacaste, northwestern Costa Rica. - J.Hymenoptera Res. 37: 1-52.

Fernández-Triana, J. L., et al. 2014. Review of Apanteles (Hymenoptera: Braconidae, Microgastrinae) from Area de Conservación Guanacaste, northwestern Costa Rica, with keys to all described species from Mesoamerica. - Zookeys 383: 1–565.

Karmalkar, A. V. et al. 2008. Climate change scenario for Costa Rican montane forests. - Geophys. Res. Lett. 35: L11702.

Pimm, S. L. et al. 2014. The biodiversity of species and their rates of extinction, distribution, and protection. - Science 344:

Smith, D. R. et al. 2012. Hyperparasitic wasps (Hymenoptera: Trigonalidae) reared from dry forest and rain forest caterpillars of Area de Conservación Guanacaste, Costa Rica. - J. Hymenoptera Res. 29: 119-144.

Smith, M. A. et al. 2006. DNA barcodes reveal cryptic host-specificity within the presumed polyphagous members of a genus of parasitoid flies (Diptera : Tachinidae). - Proc. Natl Acad. Sci. USA 103: 3657-3662.

Smith, M. A. et al. 2007. DNA barcodes affirm that 16 species of apparently generalist tropical parasitoid flies (Diptera, Tachinidae) are not all generalists. - Proc. Natl Acad. Sci. USA 104: 4967-4972.

Smith, M. A. et al. 2008. Extreme diversity of tropical parasitoid wasps exposed by iterative integration of natural history, DNA barcoding, morphology, and collections. - Proc. Natl Acad. Sci. USA 105: 12359-12364.

Smith, M. A. et al. 2014. Diversity and phylogenetic community structure of ants along a Costa Rican elevational gradient. - Ecography doi: 10.1111/j.1600-0587.2013.00631.x:






130928 - Cacao 1500 m - Rain at La Cima.

Hiking the ant barrel.

130923 - Rincon 1430m - Strumigenys.