The KaruraKams - three still camera traps and one video trap, all donated to FKF - are revealing a fascinating array of Karura's larger mammal species. The total identified is now 20 (see April-June Newsletter Click Here).

But we are seeing more than just ID mug shots. Apart from our recent discovery of 'growsing' (browsing antelopes feeding on canopy leaves off the forest floor - see last Newsletter Click Here), the ratios of numbers of mammals 'captured' is evidence of a healthy and recovering ecosystem.

At the visible level, life is rather simple: plants grow in the soil with the help of energy from the sun and water from the atmosphere; herbivores eat plants; carnivores eat herbivores; omnivores and scavengers eat just about everything; and parasites attack everyone.  Because of the Second Law of Thermodynamics (in a nutshell, when something happens, heat is lost, forever) all of the effort in finding food, finding and winning a mate, and avoiding predators loses energy along the way. The loss of energy results in a pyramid of numbers and biomass: many plants at the bottom, a good number of herbivores in the middle, and a few carnivores at the top: like a pyramid.
In Karura Forest, the abundance of green vegetation, also known as primary production, is obvious, particularly with all the rain recently and all the indigenous trees being replanted.

Most of the mammals we see in Karura are herbivores, from bushbucks and bushpigs to slugs and giant pouched rats. Our two monkeys - Sykes and the newly-reintroduced colobus - are basically herbivores, as are all the fruit and seed-eating birds, like silvery-cheeked hornbills and Hartlaub's turaco.

Then come the carnivores, the meat eaters who mainly consume the plant-eaters. In Karura we find a number of small carnivorous predators, such as the genet, civet and clawless otter. No leopards yet, but they used to be in the forest. In the air, carnivores comprise insect-eating birds, like the common bulbul, and raptors such as the African crowned eagle (watch out, newly-arrived colobus!). And don't overlook small predators, such as Jackson's chameleon, or insect predators, like the foraging siafu (safari ants), spiders and dragon flies hawking other insects over the grassy clearings.

Omnivores, the eaters of everything, include some generalist predators like the honey badger and the side-striped jackal, or Lily Lake's yellow-billed ducks. And then there are decomposers, basically scavengers, from bacteria to fungi to black-kites, who eat the leftovers, living and dead.

The KaruraKams' photo captures (pasted onto the graphic above) reflect the ratios of species in the ecosystem: relatively few carnivore captures and lots of herbivore portraits. Next time you see an animal in the trees or along a Karura track, stop and think where it might reside in Karura's 'pyramid of life.'

The end of 2015 experienced the second wettest November in 70 years! The month's rainfall was 590mm (23in), just beating the November 1961 record of 585mm, but falling short of 2006's more than 800mm. 1961 was a year of tremendous floods throughout the country, and 2006 was the last El Niño episode. This year, November delivered 60% of the average year's rain in one month. Climate change? El Niño? Or a bit of both?
The chart above combines the long term rainfall data (thanks to the Muthaiga Country Club for records dating back to 1945) with contemporary data collected in the Gitathuru River valley on the Karura Forest boundary since 1995. The shape of the adjusted graph for the whole seven decades, plus the two trendlines (black, a 4-month running average, and orange, a polynomial fit) suggest that the area around Karura has been receiving increasingly more rain over the past couple of decades. Data over more years in the future will show if this is a blip typical of a variable rainfall regime or a true signal of climate change.

2015-2016 is supposed to be another El Niño period. Although the portend of a monster event from the November rainfall seems to have petered out in December, we shall have to wait for the next quarter's results to see if Karura will be one of the El Niño 'water winners'.

A recent tally indicates that nearly 10% of the FKF goal to return Karura to its natural state has been achieved: the map shows where some 70 ha (170 acres) have been restored (blue on the map).  There are two main targets: old fuelwood plantations of exotic Eucalyptus, Araucaria and Cypress, and neglected areas where the original trees were logged out and re-growth stifled with invasive such as Lantana camara and Mauritius Thorn creeper (Caesalpenia). The plantations were originally planted  by the colonial government in the days of steam engines to feed the famous Ugandan Railway. All the while, indigenous species have been exploited for fuelwood, building and the wood-carving cottage industry.

 

Reforestation (blue) augmenting residual indigenous forest (green)

All of the clearing, planting and tree-care work has been supported by the fees that visitors gate fees and member subscriptions, as well as from many generous private and corporate donors who have 'adopted' patches of forest and replanted thousands of trees. 

Based on experience over the past few years, we have learned that forest restoration does not necessarily require each and every new tree be planted by hand. It turns out that under the neglected plantation trees and the tangles of Lantana are a myriad of indigenous treelings just awaiting physical release and sunlight so they can shoot skyward like their parent trees who seeded them perhaps half a century ago.