Vol 2 - The Trinidad and Tobago Field Naturalists' Club

THE FIELD NATURALIST No. 2/2006Observations at Morne BleuIan LambieSince mid-December 2005 and up to the time of writing on 28th May, 2006, Pawi (Pipilepipile) have been seen on a regular basis along the Entrance Roadway to the Transmitting Stationat Morne Bleu on the Blanchisseuse Road by guests and Birding Guides of the Asa Wright NatureCentre.Also at the same general location, from mid-April 2006 to the first week of May 2006,several thousand small lace-wing butterflies (Actinote pellenia trinitatus), were seen either feedingor copulating. (Barcant 1970, Plate 18(No.7)).For further information please communicate with Dr. Howard Nelson at the Asa WrightNature Centre Telephone: 667-4655 Ext . 4(2) or email:howien@hotmail.comReferenceBarcant, M.1970. Butterflies of Trinidad and Tobago. London: Collins. 147p.The Dirt on SoilJo-Anne Nina SewlalDep’t of Life Sciences, University of the West IndiesWe walk on it everyday and treat it like dirt, literally, but what is soil? Soil is much morethan the topmost layer of the earth’s crust in which plants grow (Colinvaux 1993). Soil acts as arecycling system, waste disposal system and nutrient delivery system for habitats. It also acts as asite for germination and support for plants as well as a place for them to decay. For animals itfunctions as a refuge, sewer or an environment, and finally for decomposers it is a resource.The study of soil is called pedology, derived from the Latin word meaning “foot”. This isthe same Latin root from which words like pedestrian and pedal are derived. Following the sametrend, a person who studies soil is therefore called a pedologist.There are hundreds of different soil types in the world. But interestingly enough, soils indifferent parts of the world have different colours. This characteristic aids in their identification.Temperate soils for instance, tend to be grayish-brown, while soils in the tropics are typically red(Colinvaux 1993).If you were to remove a slice of soil you would see that it is made up of different layers likea cake. In some soils these layers are distinct while in others the change is gradual so it is difficultto see where one layer stops and another begins. But all soils can be separated into three mainlayers or horizons excluding the parent material (that is the rock which erodes to form part of thesoil) which is the very bottom, and leaf litter at the very top. At the very top is a layer of leaf litter,under which is mineral soil mixed by animals, such as earthworms. The first horizon – Horizon Ahas lost minerals through leaching by rain, but has gained from decomposition of the leaf litter.The minerals that are leached out of Horizon A accumulate in Horizon B causing it to be coloured.The final horizon – Horizon C contains weathered particles of the parent material. Under thishorizon is the parent material.ReferenceColinvaux, P. 1993. Ecology 2. John Wiley & Sons, Inc. New York. 526-527p.10