About jameststroud

PhD student with Dr. Ken Feeley at Florida International University

Can better conference location planning reduce science’s carbon footprint?


The 2014 International Biogeography Meeting in Miami, FL, attracted 409 attendees from > 40 countries. Photo: K. J. Feeley.

The 2014 International Biogeography Meeting in Miami, FL, attracted 409 attendees from > 40 countries. Photo: K. J. Feeley.

One of the most important aspects of science is networking and information sharing.  But this is becoming an increasingly difficult activity to justify given the potentially large ecological costs of attending international conferences.  Indeed, air travel – much of it associated with attending meetings – has helped to push the personal carbon emissions of scientists well above average.  As scientists, we should strive to not only educate people about the negative impacts of increasing Greenhouse Gas (GHG) emissions through our studies and publications, but also through the examples that we set as responsible citizens ourselves.  As such we need to be aware of the potential ecological costs of meetings and consider different strategies to minimize these costs.

Using attendance data from the past four conferences of the International Biogeography Society (IBS) as an example, we estimated GHG emissions for all attendees using the shortest possible direct flight distances to the meetings sites (Canary Islands in 2007, Mexico in 2009, Greece in 2011 and Miami USA in 2013) from their home countries.  Using these data we estimated the amount of GHG emissions which could have been avoided if these meetings had been held in other locations.

Average GHG emissions associated with travel to the meetings ranged from 2.5-3.0 tonnes CO2 per attendee, with an average of 857.1 tonnes CO2 emitted per meeting. For all four meetings, the average travel distances to the actual meeting locations was significantly shorter than to random meeting locations, equating to an average saving of 3402.8 km of air travel per attendee and 324.1 tonnes CO2 per meeting.  If meetings had been held at their optimal locations, there would have been additional average savings of 1866.6 km of round-trip air travel per attendee and 162.3 tonnes CO2 per meeting.

The IBS is scheduled to hold its next meeting in Bayreuth, Germany in January 2015.  We predict that the attendees to this meeting will be responsible an average of 2.5 tonnes CO2 emission each. This is 0.2 tonnes CO2 more per person than would be incurred if the meeting were held at an overall optimal location of London, UK.

Society meetings allow for the rapid dissemination of new ideas and are a necessary part of science.  We do not suggest that meetings should be done away with, but as responsible academics, serious efforts clearly need to be made to minimize the ecological costs of these meetings.  One relatively easy way to minimize ecological costs is to make travel distances and GHG emissions explicit considerations when choosing meeting locations.

Air travel routes of attendees to (left) actual meeting locations, and (right) the respective optimal (i.e., lowest possible total Greenhouse Gas emissions) meeting locations of the biennial conferences of the International Biogeography Society. Line colours indicate number of attendees per travel route; Black = 1, Red = 2-5, Green = 6-10, Blue = 11-20, Turquoise = 21-40, Purple = 41-60, Yellow = 61.120, Gray = 121-200. Average per person round-trip air travel distances and meeting-total GHG emissions that would have been saved if meetings were held in their respective optimal locations are indicated below the panels on the right.

Air travel routes of attendees to (left) actual meeting locations, and (right) the respective optimal (i.e., lowest possible total Greenhouse Gas emissions) meeting locations of the biennial conferences of the International Biogeography Society. Line colours indicate number of attendees per travel route; Black = 1, Red = 2-5, Green = 6-10, Blue = 11-20, Turquoise = 21-40, Purple = 41-60, Yellow = 61.120, Gray = 121-200. Average per person round-trip air travel distances and meeting-total GHG emissions that would have been saved if meetings were held in their respective optimal locations are indicated below the panels on the right.

Twitter: @jamesTstroud


Bermuda: Sun, Sea, and Lots of Lizards

IMG_7333 I recently took a trip over to Bermuda to explore the introduced Anolis lizard (anole) communities. Over the past century 3 species of anole have become established on the island, all originating from different Caribbean islands. Rumours were circulating of a 4th species that had newly colonised, the wonderfully adaptable and incredibly successful invasive Cuban brown anole Anolis sagrei. Joined by former FIU grad student Sean Giery, led by Bermuda’s wildlife conservation expert Mark Outerbridge, and armed only with lizard nooses and a scooter each, we set out to confirm if this was true.


It wasn’t the worst place I’ve been for fieldwork!!

Anolis grahami, from Jamaica, was the first species of anole to be introduced to Bermuda. It is a classic example of biological management gone wrong. In 1905, 71 individuals (26 males and 45 females) collected in Kingston, Jamaica, were captured, transported and introduced to Bermuda in an effort to control the fruit fly Ceratitis capitata. They were an obvious choice; voracious insect eaters, as well as being “harmless and very entertaining reptile[s]”. Within 6 weeks they had spread ~1 mile, and by 1963 the species had colonised all but an extreme northwestern tip on the island archipelago, including several small offshore islands. In 1953, an established colony of A. extremus (then A. roquet), a charmingly shy lizard from Barbados in the Lesser Antilles, was first found on Ireland Island – along the same northwestern archipelago that A. grahami had yet failed to colonise. It was most likely brought over as an accidental stowaway on a ship docking at H.M. Dockyard, the British naval base. It’s distribution remained limited, and in a decade it had hardly ventured outside of that original archipelago peninsula.


(Left) Barbados anole Anolis extremus, (Right) Antiguan anole Anolis leachi

A. grahami was then joined in the centre of Bermuda in 1956 by another Lesser Antillean congeneric, A. leachi, from the distant shores of Antigua and Barbuda. Reasons for their introduction are unknown, however like A. grahami they spread relatively rapidly, such that by 1963 they were common within a 1 mile radius of the site of their original observation. A re-evaluation of species’ distributions on Bermuda in 1991 revealed that although A. grahami and A. extremus had conserved their ranges from 1963, A. leachi had continued to expand and was now found over large areas of mainland Bermuda radiating from the original site of introduction.


Mark Outerbridge (left), Sean Giery (centre), James Stroud (right, author) docking at Nonsuch Island, Bermuda

There is only one native lizard on Bermuda, the IUCN critically endangered Bermudan skink Plestiodon longirostris. These days they are restricted primarily to small offshore islands, such as Nonsuch Island (picture below). Many of these islands are characterised by short, scrubby vegetation which provide a strong defensive structural habitat for these skinks.


Nonsuch Island – home to one of the last remaining populations of the Bermudan skink Plestiodon longirostris

And what about the brown anole? You’ll just have to read the published articles to find out!

A successful seminar , congratulations Ken!


Ken Feeley, the head of our Lab, gave a well received and incredibly successful departmental seminar today as he begins the process of tenure application (picture above). Ken discussed his past, present and future research on how plants will respond to modern climate change. He primarily discussed our Lab’s research on long-term vegetation plots in the Peruvian Andes, summarized past findings and presented the exciting directions our future research will be going in! Congrats Ken!

Mating Knight anoles (Anolis equestris) at FTBG

This morning Ken and I witnessed mating Knight anoles (Anolis equestris), a non-native lizard species introduced to south Florida from Cuba, in the rainforest section of Fairchild Tropical Botanical Gardens. They were positioned ~2.5m from the ground.



Have you seen them yet? They are in this box somewhere…



Here is a close up – still difficult to spot!



Aside from being a pretty rare observation, this is interesting for a couple of reasons; i) relatively little is known about this species’ ecology in south Florida, so records of breeding activity and location are important, ii) this species is naturally highly arboreal – they are morphologically adapted to life at the top of the trees possessing larger toepads and shorter limbs relative to more terrestrial Anolis sp. Therefore observing an breeding pair in action, potentially representing an individual’s most vulnerable activity to either competitors or predators, outside of their preferred habitat range is interesting! Why is this occurring there?

Of course, this could just be a fluke. The majority of breeding attempts may occur in their preferred habitat location in tree crowns outside of our detection. Either way, a nice piece of lizard behaviour for a Friday morning!

Anolis lizard predation in south Florida

A common concept in ecology is that predators have a strong influence on the behaviour of prey species. Anolis lizards have been used as a classic model system to investigate the effect of predator presence on the behavioural response of prey species. On small experimental islands in the Bahamas the manipulated introduction of curly-tailed lizards (Leiocephalus carinatus), a large terrestrial anole-predator, has resulted in brown anoles (Anolis sagrei) shifting higher up in the vegetation, presumably in an understandable effort to avoid being eaten (123). However, predator-prey interactions such as these which may shape community structure are often difficult to observe.

Here in Miami FL we have a rich and diverse, although largely non-native, lizard community. There are two species of “crown-giant” anoles, the Cuban knight anole (A. equestris) and the Jamaican giant anole (A. garmani), that could be potential predators of smaller anoles in the canopy of trees and upper half of tree trunks (although see Giery et al. 2013 for an empirical analysis that suggests this may not be the case). Additionally, there are several large, terrestrial lizards present which may be filling a similar role to curly-tails in the Bahamas.

Potential lizard predators in south Florida:

– *Red-headed agama (Agama agama)
– *Cuban knight anole (Anolis equestris)
– Jamaican giant anole (Anolis garmani)
– *Brown basilisk (Basiliscus vittatus)
– Spiny tailed iguana (Ctenosaura similis)
– Curly-tail lizard (Leiocephalus carinatus)
– Giant day gecko (Phelsuma grandis)
– Black and white tegu (Tupinambis merianae)

Earlier this afternoon, while taking a break from my office at Fairchild Tropical Botanical Gardens (a hot spot for any anologist visiting Miami; 1234) in a typical graduate student effort to put off work that I should be doing instead, fellow lab member Evan Rehm and I noticed some scuffling in a nearby bush. At around 2.5m, and admittedly on relatively precarious branches by this stage, sat an adult female African red-headed agama (A. agama) around 30cm from an adamantly motionless adult male Cuban brown anole (A. sagrei)! As we moved towards the bush the agama was quick to ungraciously thump itself to the floor, while the brown anole remained still. On closer inspection, it soon became apparent why both lizards were so high.


Adult male Cuban brown anole (A. sagrei) found ~2.5m high in Miami FL, supposedly following a predation attempt from an African red-headed agama (A. agama) – JStroud

The significance of tail loss/damage in a population is still debated. The classical view argues that high proportions of tail damage indicates high predation pressure, therefore prey populations are under high predation stress (1). Alternatively, high proportions of tail damage could indicate low predator efficiency, which would suggest prey populations are experiencing low predation stress (12). But the debate doesn’t stop there! Having already lost a tail, a lizard may experience either a resulting increase or decrease in predation depending on the predator species and its associated foraging tactic (1).

text2The extent of tail damage is clearer in this photo. The lizard had autotomised the lower half of it’s tail however a secondary half-completed break is also evident – JStroud

African red-headed agamas (A. agama) are similar morphologically to curly-tailed lizards (L. carinatus), although are taxonomically distinct (Agamidae and Leiocephalidae, respectively). Predation of anoles by agamas in Miami has not previously been officially recorded, and the impact of these large predators remains unclear. Unlike in the Bahamas, there are multiple predators in the same geographic vicinity that anoles need to be aware of. For example, at Fairchild, brown anoles (A. sagreicould be eaten from below by agamas, eaten at intermediate levels by basilisks and eaten from above by knight anoles!

South Florida is a tough place to be an anole!


Adult male African red-headed agama (A. agama) at Fairchild Tropical Botanical Gardens, Miami FL. The population of agamas is localised to the botanical gardens; the source remains unclear but is likely an introduction from the pet trade – JStroud


Variable definitions in community ecology

Community ecology is confusing. This is confounded by the interchangeable use of many terms in the discipline.

A bunch of other graduate students and I discussed this recently at a reading group meeting (read: beer and hot dogs), and we wondered just how variable peoples interpretations of these common terms were.

We have made a short survey (4 questions) asking you to define four common terms: ‘community’, ‘assemblage’, ‘guild’ and ‘ensemble’ – please contribute!

The survey can be found here!

Many thanks!


Forest canopies provide shade to buffer species against climate change

One of the key research goals of the Feeley Lab is to understand how species are responding to climate change, with particular focus on tree species. Global warming is increasing a worldwide trend of warm-adapted species dominance, a process known as “thermophilization”. However, the mechanisms for themophilization remain poorly understood and the process often lags behind climatic warming, with some studies even indicating little to no response.

A recent study published in PNAS (de Frenne et. al. 2013) has highlighted the importance of canopy density in buffering climatic warming for sub-canopy plant species, therefore slowing the process of thermophilization.

Using a database of >1,400 resurveyed vegetation plots in forests across Europe and North America, this study provides empirical evidence for significant thermophilization of understory vegetation. However, the extent of thermophilization was buffered in forests with dense canopies. Forests with dense canopies create a microclimate that protects species that are less warm-tolerant. De Frenne et. al. present data suggesting a relationship between canopy density and thermal tolerance of sub-canopy species; denser canopies favoured cooler plants.They added that these conditions could be a “critical mechanism” in the conservation of forest plant diversity.This sub-canopy microclimate effect is likely due to increased shading during the growing season in denser forests, which leads to cooler forest-floor temperatures. This effect may be increasing as the number of forests stands increase across the temperate zones.

This provides some useful insights into conservation management practices; is it better to fell entire areas (therefore maintain density where canopy persists) or to selectively log (which conserves large areas but disrupts canopy density).

Why do we still know so little about common species?

South Florida is a wild place for lizards. And at the moment, as the region’s most abundant native lizard, life sucks for the American green anole Anolis carolinensis.

In the recent past a wealth of invasions have occurred from exotic Caribbean Anolis leading to the establishment of up to 10 non-native species around the Miami area, annually creeping further outwards towards the Everglades. The effect of congenerics on American green anoles has been well studied; the presence of an ecologically similar competitor – such as the now widespread Cuban brown anole Anolis sagrei (Fig. 2) – has forced them higher up into the trees and off the ground.


Fig 1. Range of the American green anole Anolis carolinensis in south-eastern United States. Different colours represent genetically distinct populations – from Campbell-Staton et. al. 2012.

However, the majority of these studies have been conducted in spatially explicit areas, that is to say on experimental islands. These have merits in themselves; it allows control of many assumptions which may skew your observations. For example, in continuous space one may expect species A to simply move away from species B if spatially out-competed, however islands offer the advantage of forced interactions meaning resource partitioning and habitat shifts may be more easily observed.


Figure 2. An adult male Cuban brown anole Anolis sagrei (Photo: J Stroud)

Isolated from all other Anolis since the pre-Pleistocene, the American green anole has had it pretty easy so far. They range from the southernmost tip of the USA, Key West, north to Tennessee, and west to mid-Texas (Fig 1). However the rapid range expansion of introduced species, pioneered by the previously mentioned Cuban brown anole, has caused the anecdotal decline of green anoles in the urban and suburban areas in south Florida. Whether this population decline is true, or a shift to arboreality has affected detection rates is unclear. What is clear is that the invasion by the exotic Anolis do not seem to be limited by habitat factors – yet.

Deep in the sawgrass plains of the Everglades the green anole still persists, for the time being at least, in allopatry. It’s ecology there is almost a complete mystery. Despite extensive research on the ecosystem, we know next to nothing about this species’ ecology here. Throughout the rest of its range a wealth of literature exists, however for populations in the Everglades we are still unclear on fundamental aspects of their ecology; habitat choice, diet, reproductive biology, sleeping sites or daily/seasonal activity patterns – all axes along which competitors may cause disruption.

And this is something that always puzzles me in ecological research – often we try to run before we can walk. Natural history is the basis of much of ecology, however in the present world of big science and meta-everything, this can often get overlooked.


Figure 3. For example, nectivory in American green anoles Anolis carolinensis is a relatively undocumented and still unstudied feeding behaviour whose implications are not well understood (photo: James Duquesnel, courtesy of: S. Koptur)

The potential ecological impacts of exotic anoles on the native green anole in the Everglades are unknown, and as it stands any hypothesis would be theoretical at best. However as scientists, we must remember that some of the greatest theories have arisen from natural observations. Where would evolution be without Darwin’s twitching?

Not only does the invasion expansion of Caribbean anoles present a native species conservation issue, but the potential for a large increase in terrestrial insectivores seems a topic of interest that should merit some thought for a wide range of ecologists. The Cuban brown anole is already present at every car park along the Everglades road to Flamingo, likely transported unwittingly via humans. How long we have before they begin to disperse may just be a question of time.

I encourage all of us that have the privilege to spend time outdoors in south Florida to collect as many field notes and natural history data as possible. In this world of change, the global scale effects of climatic events and warming remain unresolved, much like the more regionalised effects of human management. The importance of these data are clear, but often overlooked; they describe reality. So I return to my original question – with such a rich history of research in the Everglades why do we still know so little about the regions most charismatic lizard?

Forest fragmentation leads to rapid species extinctions

A recent study, lead authored by Luke Gibson from David Bickford’s lab at the National University of Singapore, has documented the dramatic decline in small mammal diversity as a result of human-mediated habitat fragmentation. The Khao Sok national park, in southern Thailand, has created an island matrix of limestone karst peaks (see below) as a result of flooding from the construction of the Ratchaprapha dam.

543713_10150848904474021_574689551_nPhoto: JStroud (2011)

The rate of global tropical forest felling and fragmentation continues to increase, and a key question in conservation science is how rapidly do species disappear from forest fragments. If we are able to evaluate this then it may be possible to create a time plan for mitigation, i.e. re-connection of habitat, to minimise extinctions.

Using a classical island biogeographic model on islands of various sizes, Gibson et. al. estimate that, on average, half of all species in each fragment were lost after ~13.9 years. They comment that these extinctions were probably expedited by an invasive rat species; the implications for which provide important contributions to other studies of invasion ecology.

gibson et al

Gibson et. al. 2013

These results are particularly relevant to other fragmented forest landscapes and suggest that small fragments are potentially even more vulnerable to biodiversity loss than previously thought.