On the sixth day of their field course, Professor Nigel Paul describes how the students leave the Doñana National Park in southern Spain and head for the city of Sevilla, learning about the perils of invasive species en route.
Sad to report yesterday wasn’t the day when the bee-eaters posed for us. In fact, these birds haven’t performed to their usual standard this year and, at the risk of appearing fickle, I may have discovered a new favourite Doñana species.
Today our group of 22 first year students from Lancaster Environment Centre toured around the edge of the park, looking at a whole range of landscapes. Strawberries, raspberries and blueberries grown under massive areas of plastic tunnels, and olive groves that stretch from horizon to horizon, most irrigated to supplement the limited rainfall in this part of Spain.
Eucalyptus, an invasive species
We stop at what was once a large Eucalyptus plantation, now being returned to the original vegetation. Eucalyptus trees are extremely fast growing but use massive quantities of water - that same precious limited resource.
In the last century Eucalyptus were planted over much of the area around Doñana, and used so much water that it affected the flow of the streams that feed the wetlands. In recent decades there has been a dedicated campaign to eliminate Eucalyptus and so to restore the normal water flows.
Today we got a shock. A large new area of Eucalyptus has been planted. Why? Because Eucalyptus is now being grown as a renewable energy source as part of efforts to reduce CO2 emissions from fossil fuels. As you would expect, that led to some discussion about conservation in a world coming to terms with climate change.
Competition for land
As we descended into the flood plain of the Guadalquivir river we were confronted with another of those big challenges: balancing conservation with food production. We were surrounded by a huge area of rice fields replacing what was once a massive natural wetland.
Balancing priorities is made more complex here because many wetland birds absolutely love the rice fields. Even that raises some big questions. The birds love the rice fields because they support massive populations of invasive crayfish. Great for the birds, but definitely not great for just about everything else in the ecosystem. To focus on the positive, one result of all those crayfish is a massive nesting colony of white storks at las Dehesas, which was our final stop on the tour.
After a week in Doñana we’ve all probably seen a few hundred white storks, but being within a couple of metres of a nesting pair going through their courtship display is an unforgettable experience. Which brings me to my admission of infidelity to the bee-eaters.
My head has been turned by the red eyes and golden head-tufts of the black-neck grebe we saw on the las Dehesas lagoons. It’s a new species for me, so I suspect this is just a temporary infatuation, but there was no doubt from the reaction of all those who saw the grebe today that it definitely has the wow factor.
The city of Sevilla
For the final afternoon we follow the road north along the Guadalquivir to Sevilla. More than anything this is a chance for the students to relax a little after their hard work in the field all week. But we also go to Sevilla so that they can see one of Spain’s most beautiful cities.
Certainly Sevilla provides a very different aspect of southern Spain from Doñana itself, but the Guadalquivir flows right through the city so what happens here has effects right down to the National Park.
Even the city itself has some interesting ecology. Lesser kestrels nest on the cathedral. Short-toed tree creepers are on the trees in the parks. Plus feral ring-necked parakeets which are everywhere, so another opportunity to consider the peril of invasive species.
One group of students asked me to identify a leaf from one of the enormous trees that grow in Sevilla’s parks. Being able to tell them it was the same as those rubber plants that people grow as a house plant in the UK is a nice way for me to end the day.
Read all Nigel’s blogs about the rest of the trip. Learn more about studying Ecology and Conservation, or other biology and environmental degrees at the Lancaster Environment Centre, and about the fieldwork on offer to students.
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