IS CLIMATE CHANGE AFFECTING HOW PLANTS REPRODUCE? THAT'S THE QUESTION BEHIND A PROJECT LAUNCHING AT SAN DIEGO STATE THIS FALL. KPBS EDUCATION REPORTER MEGAN BURKS INTRODUCES US TO SOME OF THE SCIENTISTS TAKING PART, AND THE NATIVE PLANT THEY'RE STUDYING.
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Just as Interstate 8 drops down the bouldery pass into the Imperial Valley, a stone structure called Desert View Tower has offered motorists sweeping views of the desert floor since 1923.
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Now, it could offer a glimpse into how climate change is affecting native plants.
< NAT (00;01;07;11) Let's go to the ones on the top. >
Lluvia Flores-Renteria is an evolutionary plant ecologist at San Diego State University. The tower's owners are letting her and her students track the reproductive cycle of the cholla cacti on their property.
(00;06;37;13) Cylindropuntia wolfii is the scientific name, but the common name is wolf's cholla.
Wolf's cholla is common in Southern California's desert - waist-high tangles of cylindrical sections covered in fine spines. At sunset the spines catch the sunlight and give off a show-stopping glow.
But Flores-Renteria and master's student Ryan Buck noticed this year the chollas skipped their spring show of red and yellow blooms - except those at the tower. They fared better thanks to a weekly drink of water, so the two are back to see if the flowers developed fruit and, in them, seeds.
< NAT (00;08;05;19) So if you see a large fruit that looks juicy, let me know. >
Studies on the East Coast have found widespread changes in plant reproductive cycles as the earth warms. On the West Coast, a one point five million dollar grant from the National Science Foundation will help researchers like Flores-Renteria ask whether that's happening here and whether it's linked to climate change.
CG: LOWER ID: LLUVIA FLORES-RENTERIA | SAN DIEGO STATE UNIVERSITY ASSISTANT PROFESSOR
(00;07;09;25) This time, this year we've seen a shift. But we don't know if it's related to precipitation patterns or temperature or something else. So if we have historical data, then we can start asking these questions.
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That historical data lives here, pressed onto paper and filed away in cabinets deep in the Life Sciences Building at San Diego State.
< NAT (00;02;42;28) And just pulling this out, this was collected in 1941, April 30th >
Michael Simpson is curator of the herbarium. He shows a pressed desert shrub.
CG: LOWER ID: MICHAEL SIMPSON / SAN DIEGO STATE UNIVERSITY HERBARIUM
(00;03;07;17) There's a lot of detail that we can study. We can dissect the flower, we could soak it up in boiling water, we can look at the fruits, we can look at the plant hairs called trichomes, so we can still see a lot even though this is nearing 100 years old. But we can also take that leaf and extract DNA.
With the NSF grant, herbaria across the state will upload high-resolution photos of their specimens and information about when and where they were collected to a central online database.
(00;07;06;00) As we do this for all of California, we can begin to get an idea as to when they flowered, when they fruited in the past versus the present.
And they can use a digital map to make comparisons by location.
(00;09;18;02) One hypothesis is they're today flowering earlier in the season. And we don't have enough data to prove that but I think we'll have enough data in about three years.
Back at Desert View Tower Flores-Renteria scours cholla after cholla looking for fruit.
(00;09;24;09) Right. Well we cannot really find anything. That's sad.
Even on the sections covered with protective bags, where Flores-Renteria pollinated the flowers by hand, the fruit dried out before it could mature.
(cont'd from above) And the other thing is that when we came here and did the pollination, the manual pollinations, we saw the bees. The bees were very active … (00;09;54;16) So the natural pollination occurred and the manual pollination occurred, but as you can see all of the fruits are being aborted. So that's really scary, actually, to see all of these plants not reproducing sexually.
The plant can still clone itself by dropping sections off its branches to take root elsewhere. But student Ryan Buck says the adaptation isn't a fail-safe.
CG: LOWER ID: RYAN BUCK / SAN DIEGO STATE UNIVERSITY STUDENT
(00;34;45;10) Just imagine that you bud off and you start cloning and there's just a whole population of you. And let's say you're allergic to strawberries and the only food source you have is strawberries. Every single one of you is going to die because you can't eat. So there's not enough genetic diversity to keep going. Some species can evolve and adapt to that, but that's going to take a lot of time, and at the rate that climate change is going, they don't have that time.
Buck and Flores-Renteria will continue to track the cholla to see if this year is an anomaly or a symptom of climate change. In the meantime, they'll take the spiky, dried fruit back to the office to see if they salvage some seeds.
Megan Burks, KPBS News