Walking in Tinley’s footsteps

August 30, 2013

By Tyler Coverdale - They say don’t judge a man until you’ve walked a mile in his shoes. For the last two weeks I’ve spent nearly every day following in the footsteps of Kenneth Tinley, for a total of about 20 miles. I’ve come out the other side muddy and wet, but with immense respect for the work he did and, perhaps more importantly, what it means for the future of Gorongosa.

 

Photo: The Urema Rift Valley floodplain with Gorongosa Mountain and three Bunga Inselbergs in the background. A herd of 2,000 buffalo with attendant flock of cattle egret in the foreground ( by Kenneth Tinley, 1977)

 

Like Tinley, I am working at Gorongosa National Park as part of my PhD dissertation, which began with a collaborative effort with other members of Princeton University’s Pringle Lab to understand how the park has changed since Tinley’s fundamental work in the 1960s. As a small part of his thesis, Tinley documented the Urema floodplain plant community – what species were present, in what proportions, and which ones were grazed by the Park’s many herbivores? Four decades ago, he found that the floodplain was dominated by grasses that provided food for thousands of buffalo, wildebeest and zebra. By migrating through the floodplain and feeding constantly, these animals kept the floodplain neatly mowed and prevented encroachment by woody species and unpalatable forbs (non-grass plants).

 

Photo: The Urema floodplain today. By replicating Tinley’s methods as precisely as possible, we hope to determine how the vegetation has changed and what this change means for the Park’s restoration goals. (by Tyler Coverdale)

 

Today, almost 95% of these animals are gone, lost during the human conflict that has shaped the Park’s past and present. Without thousands of mouths to keep the forbs at bay, would the floodplain still look the same? To find out, we used Tinley’s hand drawn maps to locate the precise locations that he surveyed. We then replicated his methods exactly - laying out transect lines and identifying species in evenly spaced quadrats from the forest edge to the margins of the lake. Along the way we came across many of the same species that Tinley found, but we also found both native and non-native species that weren’t around when Tinley walked these transects. There are still patches of grass, now grazed by waterbuck and warthogs, but much of the floodplain has been colonized by dense stands of unpalatable forbs. Whether it can still support the number and variety of herbivores it once did remains an open question, but one that we hope to answer in coming years.

 

Photo: Two quadrats from our survey of the floodplain. (left) A grass lawn grazed by waterbuck, similar to what Tinley would have seen throughout the floodplain. (right) A dense and diverse stand of forbs with little grazing. (by Tyler Coverdale)

 

The Urema floodplain has always been a dynamic system, wiped clean every year by the floods only to grow anew when the waters recede. It’s a habitat that is critical for the future of the Park and the animals we all hope to one day see roaming freely, just as Tinley did forty years ago. The importance of his work is now more clear than ever – only by understanding how the Park has already changed can we hope to steer it towards the future we all envision.

 

Photo: Pringle Lab members Tyler Coverdale (left) and Tyler Kartzinel survey one of over 500 plots originally surveyed by Tinley more than forty years ago. (Photo by Josh Daskin)

 

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Bush Diaries
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