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Measuring herbivory

September 4, 2010

Meg Lowman and leaf samples

Meg Lowman, in fact, pioneered single rope climbing as a canopy access technique in the 1980’s. She sewed her first harness out of seatbelt webbing and used her gear to sample leaves in the canopy. She was interested in looking at herbivory rates of leaves. She has been collecting data about herbivory in 300 species on 4 continents for 30 years. Here in Ethiopia, as in any other place she finds herself collecting data, she has sampled a handful of trees. She collects 30 leaves randomly from different species at different heights. Meg mostly used trees that were also being used by other members of our team just to simplify collection (meaning that trees that were already being climbed for other reasons – collecting epiphytes, soils, etc. – would also be collected from).

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Climbing Trees

September 2, 2010

The view from up here

As an undergraduate student back in 2002, I participated in a tropical biology field program in Costa Rica. We had the opportunity to conduct independent research. I wanted to know there were differences in nutrients between canopy soils (soils collected in the crotches of trees, a crotch being any place where a branch meets the trunk). In order to collect those canopy soils, I had to climb trees. You may suspect that I designed my project around the awesomeness of the collection technique and you would be right. Nothing seemed more exciting or romantic than climbing trees to collect data. Science and adventure in equal parts. I almost reveled the fact that collecting samples was such an involved effort. I loved the gear. You may recognize much of it as rock climbing gear, but both tree and rock climbing borrowed the techniques from spelunkers (cave explorers). Read more…

Malaise traps (flight intercept traps)

August 31, 2010

Malaise Trap - note the collecting bottle attached at the highest part of the tent

I’ve got to look into how these traps were named. It is the first sampling technique whose name tells you nothing about how it works. A malaise trap can also be thought of as a flight intercept trap. The ones that we used were the tent looking contraptions featured above. The “tent” is divided by a central wall. Upon running into that wall, some insects will fly upwards towards the top of the net. In that uppermost corner there is a passage which leads to a collecting bottle filled with alcohol (we are using 90% ethanol or dilutions thereof).

About 10 meters up in the forest canopy

The alcohol kills the insects and preserves them. The pitfall traps use soapy water because they are only meant to be set overnight. Malaise traps can be set up for longer periods of time. Short on time, we were only able to have them up for one or two days.

Diptera - Tabanid fly with striped eyes! Photo: Phil Wittman

Malaise traps target diptera (flies) and hymenoptera (ants, bees, wasps). Coleoptera (beetles) on the other hand, upon encountering a barrier will close its wings and drop to the floor. The malaise traps miss them entirely. This is also the first type of sampling technique that takes slightly more specialized gear. Though I bet a homemade one would be easy enough to construct.

Sweep Nets

August 29, 2010

Meg sweeps a teff field (teff is the cereal grain used to make the Ethiopian sour bread called injera)

The sweep net is the type of gear that I have always associated with entomologists (bug scientists). Sweep nets do not target one particular type of insect. Like beating sheets, they are used to sample for diversity and abundance. 20 half sweeps of the net samples 10 cubic meters. The nets are meant to be swept through foliage not above foliage, which is how my untrained mind would try to use it. Having one in hand gives me a strong urge to go chasing butterflies.

A happy helper of ours - I've often been asked where these children come from. Essentially, they see us drive up to the forest and curiosity does the rest.

Meg and I sampled by sweep net along the forest edge at both sites and in the barley and teff fields in Debresena. We also swept amongst Eucalyptus stands to see if we came up with a different set of insects. Without the data in front of me, I know that there were fewer insect orders and smaller numbers  of the ones that were present. As an introduced species, the eucalypts do not have many natural herbivores or inhabitants – in stark contrast to the native species. Though eucalyptus may be a good lumber and fuel crop, it doesn’t perform the same ecosystem services (home for pollinators, seed dispersers, seed germinators, herbivores, etc.) that native species do. If I haven’t mentioned it before, eucalypts are a huge drain on the water table and compete directly with local flora for water. The eucalupt fields are also difficult to recover once the trees have been harvested. The roots and stumps are difficult to remove and the soil is degraded.

Right outside the forest, amidst a Eucalypt grove, a man carries even more Eucalypt seedlings to be planted somewhere nearby

Pitfall traps

August 27, 2010

Pitfall trap

Different collecting techniques are employed to target different groups of insects. Pitfall traps are pretty self explanatory. They consist of a plastic container placed into a pit dug with a hand trowel that insects may stumble and fall into. They are filled with about an inch of water mixed with dishwashing liquid. The soap is supposed to lessen the surface tension of the water so that insects that would normally be able to rest upon the surface tension would instead pierce the surface of the water, sink, and be caught. In reality, these pitfall traps may also catch flying insects: diptera (flies) and hymenoptera (bees and wasps). Other common catches include isopods (pill bugs), acari (spiders and mites), coleoptera (beetles), and hymenoptera (ants) to name a few.

Edge between forest and field

We placed pitfall traps in groups of three at each of the following three sites: forest edge, interior, and field (outside the forest). We are looking for trends in diversity (total number of orders) and abundance (numbers of individuals in each order). We hypothesize that the diversity and abundance would be highest in the forest interior followed by the edge and the field. However, our forest interior site is in the clearing where the church itself is situated. These forests may very well have two edges: an outer edge and an interior edge. Edges exist whenever there is a boundary between two contrasting environments. In this case, forest interior vs. man-made clearing.

A handful of team members will be addressing this question of edge using different experimental designs/sampling techniques. Stay posted for more.

The church forests: what we’ve learned so far

August 24, 2010

Eucalyptus lumber for sale

Eucalyptus, a fast growing non-native species of tree, is grown widely as a lumber crop. You see huge piles like these lining the roads for sale. One would think that these Eucalyptus crops would be a sufficient alternative to cutting down trees in the church forests. But Alemayhu tells us that trees in the forest are still being cut down.

Eucalyptus (the stand of trees on the right) is a big cash crop and grown extensively

We have so many questions about the forest here. Many of us were surprised at the degree of degradation that this forest has been subject to. The understory of the forest has been cleared for food crops like coffee, foot paths criss cross the forest, only the trees remain of the original forest community.

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Day 12 – First day of sampling

August 23, 2010

Besides the usual call to prayer, we woke up to the sound of rain. Rain is not a good thing for most types of field sampling. Insects tend to go under cover. Our first of two church forest sites is about an hour’s drive north of Bahar Dar. We packed up the SUV’s and piled in. It was quickly established that all team members under 35 had to sit in the rear of the SUV’s. There is a 60 year age spread among our team from 19 – 79. I am the second youngest member at 28. My hats off to the folks over 75! A reminder that life is long and to never use age as an excuse for not doing something.

Churches are community centers, white robed church members fill the courtyard

We arrived at the church forest and took a walk around the 8 hectare site. 8 hectares not only sounds small, it looks small too (the forest may have shrunk some since the last time it was measured 2 years ago). Standing in the center of the forest, where the church is located, you can very nearly make out the edge of the forest. Yet it was refreshing to see a forest filled with indigenous (native) and endemic (found only there) species. A number of walking paths intersect the church, which contributes further to its fragmentation. The church clearing in the center of the forest acts an interior edge (120 divinity students live in this forest).

Hunched over a beating sheet, I am showing some local children what I've collected with my aspirator

We split up into teams to work on various projects. I started off sampling by beating sheet with Meg. We took our first set of data on the forest edge. We mostly sampled under an exotic (not native) bush with bright yellow flowers. We placed a 1m x 1m sheet of white ripstop nylon on a PVC frame (the beating sheet) underneath a bush before shaking it vigorously for 10 seconds. During the shaking, you look for insects dropping onto the sheet. Then you tally up the number of individuals for each order present. We sampled 6 times and saw primarily beetles, beetle larvae, thrips, leaf hoppers, weevils, flies, mites, spiders, bees, isopods, and ants.

Meg Lowman records data with future scientists lending a hand (that head covering on the left is a rolled up plastic bag which is slit open and used as an umbrella - the modern version of the woven ones)

We attracted a large following of passerbys. The children were excited to be sampling with us. A few young men spoke English well enough to ask us about our reasons for being in the forest. Though we have not been teaching in any formal capacity, we are here as ambassadors of conservation. These young men helped us to get our message across more clearly (in Amharic) to some of our younger helpers: we are studying the forests to find ways to keep it and the communities around it healthy for many generations to come.

Day 11 – Birding/Church Forest Excursion

August 19, 2010

After breakfast, we piled into two launches heading north along the eastern coast of Lake Tana. Two hours later, we arrived at an island that is a breeding ground for many species of birds. The island lacks large predators which leaves the birds in peace to raise their young. We saw sacred ibis, white winged black tern, herons, cormorants, and spoonbills. The birders among us were quite excited and the non birders among us learned a lot, myself included.

This impromptu church was quickly built when the original one - on the circular foundation to the right - burned down

On our way back, we visited a church forest. This was my first opportunity to see the inside of an active church. I don’t have many pictures now, though there are some very fancy DSLR’s among us that perform well in low light conditions.

Members of the church wear traditional cotton shawls. Each church consists of three concentric circles. The two outermost circles are open to the public. The innermost circle houses the altar of the church, religious texts, ceremonial ornaments, and a replica of the ark of the covenant (all churches must have a replica). The outside of the central section is painted with religious imagery (much of it gruesome, featuring the martyrdom of a variety of saints), using natural plant dyes on mud walls or goat skins.

A first look at some common trees in the church forests

Some of these churches have religious texts that are hundreds of years old. The church protects these sacred relics, the forests, in turn, stand to protect the church. Alemayhu says that since the fall of Haile Selassie and the rise of secular socialism, the clergymen have not been receiving the subsidies that they rely upon. This has led to a degradation of these forests out of a desperation. He worries that in a few years there may not be much left to protect.

Today was a light day as everyone is still adjusting to the time change. The long boat ride gave us ample time to get to know one another a little better. I may try to write up everyone on the team, but the collective experience among us is absolutely astounding. Many of the scientists are professors and we’ve had interesting conversations about students and teaching. It’s nice to hear a little more from educators at the university level.

Day 10 – Back in Bahar Dar

August 19, 2010

I can stop waxing poetic about long bus rides since I took my last one this morning. The team arrived in Bahar Dar this afternoon. We gathered together for an inaugural meal. Alemayhu Eshete Wassie, a tree ecologist, is the man who inspired our work. He brought the plight of the church forests to international attention (Meg spotted him during student presentations at a conference in Mexico).

I will take some time to introduce each and every one of the team members in due time, but I will summarize my first impressions here.  Much of the team is acquainted with Meg either personally or professionally. Upon hearing about the church forests, many were already on board. Meg has assembled a diverse group of experts in entomology, botany, ecology, herpetology, geology, historical fauna and flora, to name a few. Some are academics, scholars by trade, and others are hobbyists. When I say hobbyist, I understate their degree of expertise. These are “hobbyists” who have published books and scientific papers and are highly regarded by their peers in the scientific community. I am always inspired by these auto-didacts who are fueled by an insatiable curiosity and a passion for their subjects, which they maintain in addition to their day jobs.

Alemayhu shares his new Ethiopian tree guide gifted to him by the team

Each member has slightly different research aims, but we are all committed to promoting the conservation of the church forests through our work here.

August 17, 2010

Terefu, Solomon, and Shumet - friends from Sakota!

Serendipity. I try to open myself up to moments like these. Rather than go to Lalibela, I spent some time experiencing village life in Sakota (rhymes with Dakota). Terefu and Shumet happened upon me on my way to catch a minibus to Lalibela. They said that they were going that way and that I should come with them. They’re Toyota 4X4 looked so spacious and comfortable compared to the hypothetical minibus I was on my way to meet. How could I say no?

Sakota - somewhere near the bus station

Sakota is your typical mid-sized town. Two major roads lined with shops bisect the town.  Every walk I took with Terefu took 15 minutes longer than you would expect. Terefu knows everyone in town. Our pace is leisurely, we literally stroll. We stop to talk to everyone: Salaam. Duenanesh? Duenani. Three kisses, cheek to cheek. Hardy handshake for the ferenji: Where are you from? America. But you look Chinese. My parents are from Hong Kong.

Solomon's office

Solomon is a governmental administrator of some kind. I couldn’t get a better description of his work. I know that he is a very busy man and that people of all sorts visit his office. I can only guess at the identity of all of his visitors.

The last shot my camera took outside the rock-hewn church

Solomon took me to visit some of Sakato’s churches. St. Gabriel church, right in town and Waghimra, a rock-hewn church that predates the Lalibela churches by 500 years. My camera took just that moment to crash completely so I have no photos. The church is carved right into the cliff side. The craftsmanship is very impressive, as awe-inspiring as a place of worship ought to be. More recently painted goat skins depicting religious scenes hung from the high ceilings. The church was partitioned by embroidered panels of red cloth. The floors were worn smooth by the feet of bygone pilgrims. Our guide, a young priest in training, showed me a hole in the floor of the church. Two tunnels led from this hole and are rumored to be connected to the churches in Lalibela (over 60 miles away).

Later that night, a few self appointed teachers taught me some traditional Ethiopian dance moves. There was a great deal of laughter over my imitations. As far as I can tell, shoulder shaking is a major component. My friends were pretty entertained that I took to it with such gusto.