Tag Archives: Research

Some Streams at Las Alturas

Thickly vegetated headwaters streams scar the mountain-sides in the primary forest at Las Alturas.  Currently, not much research is being conducted at the station, but a couple of mentors are interested in setting up i-buttons (remote temperature and humidity monitors) to collect data on an elevational gradient within the forest.  This is of interest given some dramatic shifts in forest communities elevation changes (hence, the microclimate of the mountain-side changes), and climate change forecasts in the region.  As the regional climate changes, these forest communities are expected to shift up or down in elevation, but communities may disappear if they can’t compensate (e.g., the community at the top of the mountain may have nowhere to go).  I think monitoring streams is of interest as well.  For instance, alterations in precipitation, which are also predicted by climate change, can lead to altered hydrological regimes within these streams, which could lead to stream community and ecosystem change.  Simply picking up a few rocks, I observed hundreds of Simuliids (blackfly larvae), some psephenids (water penny beetles), mayflies, and damselfly larvae.

Perhaps this is a good enough reason for me to visit, and stay, again…

Sendero Chai: A transitional mountain hike

The station at Las Alturas sits adjacent to La Amistad, and there are a few trails (senderos) that meander into the primary forests of the reserve.  One such trail is Sendero Chai, a straight hike up about 600 m to the peak of Cerro Chai at 2100 m asl.  The trail brings one through several forest types, beginning at tropical, premontane wet forest, and ending in some shrub forest at the peak, because these forest types are linked with elevation. It’s an astonishing 2.5 kilometer journey.

Mixed between the peak forest-type and the wet forest is some montane oak forest and a thin band of bamboo-oak.  The wet forest has many large strangler figs and Cedrela, amongst other species.  I believe the high elevation oaks are Quercus costaricensis, but there are several species of oak in high elevation locations throughout Costa Rica.  When passing through the oaks, the forest become a bit quieter and the forest floor feels thick and soft; there is a thick layer of leaf litter that accumulates in these forests, and the litter absorbs sounds like snow.  These habitats are my favorite terrestrial types because of their calm nature and tannin-y smells.  Cerro de La Muerte sits in this habitat type, but Sendero Chai was the first time I was able to clearly observe transition between forest types.

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Track and waypoints indicating approximate locations of forest transitions up Sendero Chai.

 

Here are some photos from each forest type, starting from the top, shrub forest, working through bamboo and oak, and finishing with wet forest.


Investigating animal decomposition in a tropical wet forest and agricultural lands

Michael, an undergraduate researcher out of Stanford, is working at Las Cruces on animal decomposition.  Briefly, he’s set out freshly-killed adult chickens and chicks in forests and agricultural lands (i.e., pasture and coffee plantation) and monitors what happens…

He’s got camera traps trained on the adult chickens, and uses transects through both habitat types to pair replicate locations with both major habitats.  It’s interesting (and rather smelly) work: there are a number of specialist scavengers that feed on animal matter, and the roles animal detritus (feces + dead animal) play in communities is often overlooked in light of the overwhelming biomass that plants input into detrital pools in ecosystems.  Michael has already found some exciting facilitation effects within the scavenger community.

Michael was kind enough to take me along on one of his sampling dates.

Litter grinding

Many of the litter samples I brought to Holden Arboretum were not sufficiently ground for Elemental Analysis, so I used a coffee grinder to break up tough litter material (like cattail and Thalia), and then sub-sampled that material to grind in small red-capped vials with metal beads in them.  Here are a few photographs of the process.

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Large vials filled with partially ground litter

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Smaller vials with more finely ground litter

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Grinding beads
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Partially ground cattail litter in the coffee grinder
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After photograph of ground cattail litter
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A subsample is taken to place in the small red-capped vials
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The coffee grinder... sophisticated science equipment.
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A finished sample.