The Feeley Lab goes to Colombia

One cannot think of a better way to spend the Spring Break than working in the Colombian Amazon. Sharing this very sentiment, four students of the Feeley Lab, Catherine Bravo, Tim Perez, James Stroud and I (Belén Fadrique), as well as Dr. Feeley himself, travelled to the heart of the Amazon.

The objective was to carry out research projects that will contribute to the conservation of Amazonian biodiversity. For this reason, we went to one of the most highly diverse forest in the world, the Parque Nacional Natural Amacayacu, DSC07703located close to the border between Colombia, Peru and Brazil. For accessing the park we had to go to Leticia, a Colombian city known as the door of the Amazon. From there, we took a boat that sailed along the Amazon river, stopping at the indigenous communities until arriving to the Amacayacu station. The station is built on the Amazon shore and as we were in the rainy season, the only way to arrive there was by boat.

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The whole team ready to get wet

We were a diverse group formed by the four FIU students, two undergraduate students from Universidad Central Medellin, Andrés Barona, plot manager, Dr. Juan Saldarriaga, invited professor, Dr. Feeley and Dr. Alvaro Duque. As a whole, we added up to five nationalities, therefore breakfast and dinner were moments for comparing and contrasting the different cultures and traditions of our own countries.

Dr. Duque was the person who made this adventure possible. He invited us and provided us with all the necessary logistics for the success of our projects. Dr. Duque is the Principal Investigators of the plot. The Amacayacu plot (-3.80917, -70.2679) is part of the CTFS (Center for Tropical Forest Science) network; it was established in 2007 and has an extension of 25ha. The plot is located in the tropical moist forest life zone (Holdridge et al., 1978) in the Pebas formation, on Tertiary sedimentary plains characterized by a hilly and slightly dissected topography. Annual mean precipitation is 3000 mm and monthly average temperature is 24-26ºC. In the plot, all trees are tagged and identified following the CTFS protocols.DSC07750

In order to reach the plot from the station, we had to go through the flooded forest by boat. The first day, Dr. Duque and Andrés Barona offered a guided visit where they showed us basic notions for orientation inside the plot. I don´t think I was fully oriented until the last day of work.

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Catherine Bravo trying to get oriented in the plot

During the five days of field work, we collected and processed leaves of understory species located on different levels of soil convexity, a proxy to soil moisture. Tim Perez measured several leaf traits and Catherine Bravo investigated drought tolerance. The common goal of our projects was to study phenotypic plasticity in understory species.

My project about intra-individual plasticity and the temperature-size leaf relationship did not work for technological difficulties. For that reason, I started another project that would contribute to both, diversity conservation and to the other projects carried out by the lab. Therefore, I decided to study herbivory patterns in understory species. I scanned the collected leaves in order to calculate, by using computer software, the percentage leaf consumed by herbivores. With this information, I could relate the herbivory percentage with the rest of the functional traits measured and with the soil convexity. Maybe thinner leaves are consumed more. Or maybe, if the leaves are tougher they can avoid being eaten by herbivores. Would this change with convexity?

While you look at the butterfly, I look at the holes on the leaves

While you look at the butterfly, I look at the holes on the leaves

Results from this and the other projects will arrive soon to this blog!

This experience has been a unique opportunity which has reminded me why I do what I do. Studying for weeks for an exam is worthy if at the end I get to go to the heart of the jungle, wonder why things are like they are, and I get the support for researching and experimenting until my questions are answered.

Additionally, this journey allowed us to establish new links between the groups of Dr. Feeley and Dr. Duque and to strengthen the already existing collaboration. In addition, this project was the result of the joint collaboration of the different participating institutions in the initiative: Socios para la Conservación de la Amazonía Colombiana, which funded me to carry out the project and which I am very grateful for.

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The Amazon river

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First two to defend!

Two of the founding members of the feeley lab and upwithclimate team have successfully defended their doctoral dissertations.  On February 27th, 2015, Evan Rehm defended his dissertation on the “Factors affecting current and future treeline locations and dynamics in the Peruvian Andes” and on March 18th, 2015, Brian Machovina defended his dissertation on “The role of agriculture and food consumption in tropical conservation” (The abstracts of both dissertations are included below).

7538579534_d70249a588_n-002Evan is moving immediately into a position as a postdoctoral researcher with J. Savidge based out of Colorado State U. but working on Saipan Island to study the effects of bird loss (due to invasive brown snakes) on seed dispersal and vegetation composition and dynamics (see HERE for more information about the project).

IMG_0091Brian is going to focus on writing a book that expands on his dissertation research and discusses the environmental and health impacts of human carnivory (i.e., eating meat).  He will also keep working with Yonanas, the fruit “ice cream” maker that he invented.  Brian plans to stay involved at FIU and will keep dabbling in research.

We are very proud of both Brian and Evan!  Congratulations to both of them on all that they have done and for all that they will do!

ABSTRACTS:

Factors affecting current and future treeline locations and dynamics in the Peruvian Andes

by Evan M Rehm

0227150950The elevations of tropical treelines are thought to be determined primarily by temperature. As such, treelines are predicted to shift upslope in response to global warming. In contrast to this hypothesis, global-scale studies have shown that only half of studied treelines are shifting upslope despite rising mean temperatures. Understanding how treelines will respond to climate change has important implications for global biodiversity, especially in the tropics where tropical treelines represent the upper distribution limit of the hyperdiverse cloud forest system. In this dissertation defense I will introduce the idea that grasslands found above tropical treelines may represent a potential “grass ceiling” which forest species cannot invade. There are many potential mechanisms which may act to stabilize treeline and prevent forest expansion into high-elevation grasslands, including mean temperature controls on growth, extreme low temperature events which kill actively growing tissues and intesnse solar radiation at and above treeline. Through a series of observational and experimental approaches, I show that microclimatic conditions around treeline are extremely important in determining seedling recruitment patterns. However, contrary to our current understanding of tropical treelines, low temperature extremes may be more important than mean temperatures in determining tropical treeline shifts in response to climate change. In addition, increasing mean temperature actually has a negative effect on seedling survival of at least some treeline species. This work demonstrates that mean temperature is a poor predictor of tropical treelines and that temperature extremes, especially low temperatures, and non-climatic variables should be included in predictions of current and future tropical treeline dynamics.

The role of agriculture and food consumption in tropical conservation

by Brian L. Machovina

0318151005aA growing human population, shifting human dietary habits, and climate change are all negatively affecting global ecosystems on a massive scale. Expanding agricultural areas to feed a global population predicted to reach 9 billion drives extensive habitat loss, and climate change compounds stresses on both food security and ecosystems. Understanding the negative effects of human diet and climate change on agricultural and natural ecosystems provides a context within which potential technological and behavioral solutions can be proposed to help maximize conservation. The purpose of this research was to (1) examine the potential effects of climate change on the suitability of areas for commercial banana plantations in Latin America in the 2050s and how shifts in growing areas could affect protected areas; (2) test the ability of small, inexpensive unmanned aerial vehicles (UAVs) to map productivity of banana plantations as a potential tool for increasing yields and decreasing future plantation expansions; (3) project the effects on biodiversity of increasing rates of animal product consumption in developing megadiverse countries; and (4) estimate the capacity of global pasture biomass production and Fischer-Tropsch hydrocarbon synthesis (IGCC-FT) processing to meet electricity, gasoline and diesel needs. The results indicate that (1) the overall extent of areas suitable for conventional banana cultivation is predicted to decrease by 19% by 2050 due primarily to hotter and drier climate, but all current banana exporting countries are predicted to maintain some suitable areas with no effects on protected areas. Several countries are predicted to experience large net decreases in the extent of areas suitable for banana cultivation while others are predicted to experience large net increases in the extent of suitable areas; (2) Spatial patterns of NDVI and ENDVI were significantly positively correlated with several metrics of fruit yield and quality, indicating that UAV systems can be used in banana plantations to map spatial patterns of fruit yield; (3) Livestock production is the single largest driver of habitat loss, and both livestock and feedstock production are increasing in developing tropical countries where the majority of biological diversity resides. Reducing global animal product consumption should therefore be at the forefront of strategies aimed at reducing biodiversity loss; (4) Removing livestock from global pasture lands and instead utilizing the biomass production could produce enough energy to meet 100% of the electricity, gasoline, and diesel needs of over 40 countries with extensive grassland ecosystems, primarily in tropical developing countries.

A downside of diversity?

Stroud and Feeley have just published a short  letter in Trends in Ecology and Evolution proposing a new “downside of diversity” hypothesis. A slightly modified version of the article is included below.

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A downside of diversity? 

James T. Stroud1, 2; Kenneth J. Feeley1, 2, *

1. Department of Biological Sciences, Florida International University, Miami, FL 33199, USA. 2. Fairchild Tropical Botanical Garden, Coral Gables, FL 33146, USA, * kjfeeley@fiu.edu

Keywords: conservation; specialization; ecology; extinction; biodiversity; niche

Niche theory as a predictor of extinction probability

Species with narrow niches (specialists) generally have lower ecological resistances (i.e., are more sensitive to environmental disturbances) than similar species with broader niches (generalists). Gallagher et al. [1] recently demonstrated this relationship between niche breadth and extinction vulnerability by highlighting the elevated extinction probabilities for specialist versus generalist species across a broad range of taxonomic groups. We suggest that the incorporation of ‘niche packing’ theory allows us to predict which communities should have constituent species at greatest risk of extinction.

Specialists can be highly prone to local extinction following habitat loss because the resource(s) required by the species are often missing from any remaining habitats [2]. In the case of climate change, changes in temperature and precipitation regimes can quickly shift habitat conditions beyond the narrow requirements of specialized species [3]. Therefore, in the absence of rapid adaptation and ‘evolutionary rescue’, relatively minor changes in climate can force specialized species to shift their geographic distributions [4]. Even with migrations, specialized species will be at an inherent disadvantage because areas that offer both suitable climates and the required environmental conditions will be relatively sparse. By contrast, generalists will be better able to tolerate environmental changes because these species are by definition capable of persisting across a wider range of conditions.

Considering the strong connection between the degree of specialization of a species and its sensitivity to disturbance, we argue that extinction probability must then be predicted to be highest in those areas that support the largest numbers or proportions of narrow-niched species. Theory provides us with one tool for predicting where these specialist species are most likely to occur. Specifically, the theory of ‘niche packing’ states that, because of heightened interspecific competition, the species that occur in biologically-diverse communities will tend to have narrower niches (i.e., will be more specialized) than will similar species in less-diverse communities [5].

Taken together, these two theories – the increased sensitivity of specialized species and greater niche-packing in more diverse communities – dictate that the intrinsic extinction vulnerabilities of species should generally increase with diversity. In other words, we hypothesize that there is likely to be a ‘downside to diversity’, such that the species comprising more-diverse communities are inherently at greater risk of extinction than are species of depauperate communities.

The downside of diversity: a tropical problem?

The most biodiverse communities in the world are located in the tropics [6]. Tropical species are widely believed to be more sensitive to climate change than their temperate counterparts because of (i) the absence of a marked latitudinal gradient of temperature within the tropics, which results in greater distances between current and future climate analogs, and hence faster climate-change velocities, necessitating faster rates of species migration 7 and 8; (ii) rapid rates of habitat loss which decrease habitat availability and increase the distances that species will be required to migrate to keep pace with changing climates [9]; and (iii) the prevalence of species with narrow climatic niches due to the short- and long-term climatic stability of tropical environments [10]. As discussed above, the diverse communities of the tropics will also generally exhibit intense interspecific competition and niche packing. Therefore, tropical species can be predicted to have narrower niches, even regarding non-climatic factors such as diet preference and habitat use, than their temperate counterparts [11]. According to our proposed ‘downside of diversity’ hypothesis, extinction probabilities may therefore be even higher in the biologically-diverse communities of the tropics than was previously anticipated.

With the massive number of extinctions that are forecast as we enter the ‘Anthropocene’ [12], it is crucial that we identify the systems and communities under greatest risk of species loss – we cannot afford to wait to construct models post hoc based on observed extinctions. Combining the observed specialist species increased extinction vulnerability with the classic theory of niche packing, we can predict that highly-speciose communities and their constituent species are at high risk of extinction from environmental disturbances such as climate change and habitat loss. Given this potential downside to diversity, we argue that there is additional motivation to prioritize the conservation of high-diversity communities in the tropics.

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