Tag Archives: biodiversity

Measuring Biomass and Diversity in Ecosystems

Even the snakes at my house are curious! (Image credit: Brad Kremer)

Even the snakes at my house are curious! (Image credit: Brad Kremer)

Environmental scientists, national park wardens, reserve managers, and conservation officers are the people making the decisions about Tanzania’s abundant wildlife resources. Many of the choices they make about the areas and organisms they protect are based on political and/or economic considerations, but most of those decisions will have at least some foundation in scientific knowledge.

How do we know which living resources are present in a national park or reserve? How do we know the number of elephants or eland or egrets in a wildlife management area? These are some essential questions for anyone charged with sustainably managing a country’s natural resources. Luckily for all of us, science has some answers!

The Lincoln Index is a tool used to estimate populations of mobile organisms in an ecosystem. The Lincoln index answers the question, “How many?” There are 4 key steps to properly conducting a Lincoln Index survey:

  1. Capture: systematically catch organisms without harming them

    Lincoln Index formula. See the syllabus for a further explanation on its use.

    Lincoln Index formula. See the syllabus for a further explanation on its use.

  2. Mark: mark the organisms in a way that does not harm them
  3. Release: let them return to their natural habitat
  4. Recapture: catch another

These 4 steps will provide some key data points, which can be plugged into a mathematical formula, shown at right, which estimates the total size of the population in the area sampled.

Another highly useful tool for measuring biotic components of ecosystems is the Simpson Index, or the Simpson Reciprocal Index. The Simpson Index measures the diversity of an ecosystem. Simpson accounts for both aspects of diversity, as defined in our ESS syllabus: species richness (the total number of species present) and species evenness (the number of individuals of each species present). The process for calculating Simpson’s D-value is a little more complicated than that for calculating Lincoln, but not much. Please check the ESS syllabus for details.

Simpson's Diversity Index. See the syllabus for further details on its use.

Simpson’s Diversity Index. See the syllabus for further details on its use.

We’ll be simulating 3 different ecosystems in class over the next couple of days, so you should have plenty of opportunity to test out these formulae and manipulate some of the variables within them. Both of these procedures will help you tremendously on the ESP week of field work in Zanzibar. (Hint, Hint)

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The Ivory Trade, Organized Crime, and Questions About the Effectiveness of CITES

I’ve posted this first article before – from the UN Office on Drugs and Crime – which outlines the links between ivory from east Africa and narcotics in Asia. The embedded version is the short one, and the full version is available to download here: Ivory and Organized Crime in East Africa.PDF

The following item is a dissertation research paper by Justine Braby, an Environmental Law Postgraduate candidate at the University of Cape Town. In it, she examines how effective the CITES ban on ivory has been since implemented. CITES is the Convention on International Trade in Endangered Species, a global framework for reducing and/or eliminating the trade in all endangered organisms for commercial gain. The CITES website has a lot of very specific information directly relating to the ESS Topic 4 – Conservation and Biodiversity, as well as the Grade 9 poaching project. I recommend you check out both the articles posted here, as well as the CITES page.

Western Black Rhino Officially Extinct – IUCN

A sad day for conservationists, as the International Union for the Conservation of Nature declares the Western Black Rhino officially extinct.

Western Black Rhino -R.I.P. (Image credit: www.skullappreciationsociety.com)

Western Black Rhino -R.I.P. (Image credit: www.skullappreciationsociety.com)

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Effects of Poaching on People and the Environment

The University of Washington’s Center for Conservation Biology released this study a few years ago, detailing the impact of poaching on elephant populations in Mikumi and Amboseli.

Graphic from University of Washington's Center for Conservation Biology

Graphic credit: University of Washington’s Center for Conservation Biology

I post this link for several reasons:

  1. The topic is clearly relevant to both the grade 9 biology unit, as well as ESS’s Topic 4 – Conservation and Biodiversity.
  2. The study was carried out in conjunction with Sokoine University in Morogoro, just a couple of hours from here.
  3. The targeted areas are Mikumi National Park in Tanzania and Amboseli in Kenya, so it’s entirely relevant to where we live.
  4. The inclusion of simple graphs with the article complement and support the written work of the authors, and it can serve as an example to you students about how to use visual aids in your scientific writing.
  5. Follow the ‘Research Programs’ and ‘Elephants’ tabs to see how DNA analysis is being used to track poached ivory.
  6. I like the graphic at the top of the page.

I also found this 2006 document from the World Wildlife Fund – the Wildlife Trade Factsheet 2006.PDF – which “is designed to give a broad overview of the environmental harm that illegal and unsustainable wildlife trade can cause, and to give examples of WWF and TRAFFIC’s work and solutions on the ground.”  (www.panda.org)

WWF Image Credit: Martin Harvey

WWF Image Credit: Martin Harvey

Link

Ivory Confiscated in Mikocheni – 200 Elephants Dead

While I was at the AMMUN conference in Jordan, IPP media published this article about a recent ivory haul in Mikocheni, just a few blocks from my house in Dar es Salaam. Police uncovered more than 700 pieces of ivory, “representing more than 200 tuskers killed,” according to the newspaper’s sources.

I post this link because I want you to realize that poaching isn’t just something that happens ‘out there’ in the bush. It is inherently linked to the trade and economy of Dar es Salaam, and it is happening in our neighborhoods. You probably sit next to someone who is somehow involved in poaching each time you’re stuck in one of Dar’s famous traffic jams.

Poaching in East Africa

One of my favorite things about living in Tanzania is the amazing diversity of ecosystems in this country – the grassy plains of the Serengeti, mist-shrouded slopes of volcanic mountains like Kili and Meru, vibrant coral reefs of Mafia and Mnemba islands, the waterfalls and forests of the southern highlands, and the semi-wooded savanna of the Selous all come to mind.

Mikumi savanna.  Image credit: Brad Kremer

Mikumi savanna.
Image credit: Mr Kremer

Habitat diversity like this gives rise to an incredible level of biodiversity, with a large number of endemic species found across Tanzania: Zanzibar red colobus monkeys, Pemba flying fox, the kipunji monkey of the Udzungwa Mountains, Ancistrorhynchus refractus orchids from the Kitulo plateau, plus several native chameleons such as the Usambara two-horned chameleon (pictured below) and the Uluguru one-horned chameleon. Follow this link for a more complete look at Tanzania’s Living National Treasures.

West Usambara two-horned chameleon.  image credit: http://mitschis-chamaeleons.de/

West Usambara two-horned chameleon.
image credit: http://mitschis-chamaeleons.de/

Sadly, Tanzania’s diversity is threatened by a rapidly-growing and highly-lucrative practice – poaching. Most poachers don’t kill or capture animals because they’re inherently evil people; instead, most of them do it because it’s the easiest way for them to earn enough money to feed their families. Food on the table trumps a pretty landscape pretty much every time.

But how does poaching impact Tanzania? What are the effects on the food webs in our beautiful national parks? What are the economic and social pressures on communities near these reserves to either actively participate in poaching or turn a blind eye to it? How does poaching’s links to organized crime influence local and national politics? These are the questions you should address in your next assignment – People and Poaching in East Africa: a One World Analysis.

Below, once again, is the UN document outlining the links between poaching, organized crime, and the illicit drug trade in East Africa. It’s a little dense but still pretty fascinating to read, if you ask me.

Here’s another presentation on elephant poaching, which links east Africa with the Philippines and other parts of Asia.

And lastly, check out this AFP article about a hunting group in Texas, USA, which wants to sell a permit to kill one endangered black rhino in Namibia as part of an effort to save the species. What do you think of this approach?

The Habitable Planet

I just stumbled upon this course at Learner.org, called “The Habitable Planet: A Systems Approach to Environmental Science.” I haven’t had the time yet to fully explore it, but it looks to be a tremendous resource for our class. I recommend you bookmark this page in your browser and come back to it whenever we start a new topic (or when you’re revising for mock exams, topic tests, and/or the IB Exam. I will definitely be consulting it for some activities in future lessons.

Here’s a screenshot of the major topics you’ll find. Screen Shot 2013-10-02 at 09.29.23

 

Ivory, Poaching, and the Drug Trade in Tanzania

Thanks to Matt Erdosy for passing this along to me, and to Neil and Liz Baker of the Tanzania Bird Atlas for their contribution. Below please find a short version of a recent report from the United Nations Office on Drugs and Crime, which details the extent of ivory poaching in Tanzania and other east African nations. The numbers are just staggering:

  • Over the last 10 years a third of Tanzania’s elephants have been slaughtered.
  • 20 elephants were killed in the 2nd quarter of 2013 in Tanzania’s protected Ngorongoro Conservation Area.
  • One prominent Tanzanian Game Reserve and a National Park have lost 42% of their respective elephant populations over the last 10 years, amounting to a staggering count of 31,348 carcasses.
  • 10,000 elephants are killed annually (that’s 27 elephants a day, or just over one every hour!).

The rest of the report is pretty fascinating as well. It details migrant smuggling in the Horn of Africa region, heroin trafficking from Asia into Africa, and piracy from Somalia. Click on this link to read the full document, Transnational Organized Crime in East Africa: A Threat Assessment.