So what does it really take to save an endangered species? Culturally, we have come to the general conclusion that we should save the baby seals and rare owls- as long as it doesn’t inconvenience our finances or personal property too much. Our leaders designate parks, preserve areas from logging, and draw no-fishing zones to protect the habits that we’ve been told our favorite charismatic animals need to survive the odds we’ve stacked against them. However, most of our planet’s endangered species are not as bumper-sticker worthy as the whales. Save the Wedgeleaf Button Snakeroot! just doesn’t have the same successful sound; it is difficult to pull on people’s heartstrings for a small herbaceous plant. Endangered plants, in general, receive far less attention than their more animated animal list-mates.
So allow me to introduce you to one very uncharismatic
endangered species, Ziziphus celata, commonly known, to the handful of people who know it, as Florida Ziziphus. It’s a spiky shrub from the buckthorn family, growing in sandy upland sites along the Lake Wales Ridge in south central Florida. It can reach 6 ft tall- sometimes on a single upright stem, but more frequently, in a twisted, zigzagging mass of stems, branches and spines, making it difficult to tell where one plant ends and another begins. It has small, alternate leaves that are typically dark green with a shiny upper surface, and sometimes slightly heart shaped. On many older individuals, the older, woody branches are leaf-less, just gray bark and thorns.
The flowers begin as clusters of small green buds along the leafless older branches. On some of the plants, these buds are the only green present. The flowers bloom for about two weeks, at some point between late December and early February, depending on environmental factors and the plants’ personal sense of humor. Thousands and thousands of the tiny flowers can bloom on the larger plants.
However, despite the sometimes prolific flowering, Ziziphus is not thriving. Stubbornly, it refuses to reproduce sexually in the wild. It is hard to save a plant that doesn't seem to be trying to save itself. Many of the known populations are made up of plants from a single genotype- they are all clones, separate stems growing up from a shared colony of roots. These clones are self-incompatible: they can not fertilize flowers and produce viable seeds together, since they share the sam
e genes. Even when several genotypes are present in a population, some of the crosses are incompatible as well, and no fertile seeds are produced. Most of the viable seeds have been produced from painstaking, painful hand-pollinations by biologists working with the captive population at the Bok Botanical Garden in Lake Wales Florida.
Ziziphus is currently considered the one of the most endangered plants in Florida. It was first described from an old herbarium specimen- no one living had seen it in the wild- so it was presumed extinct. In 1987, the first of 7 known wild populations of Ziziphus was discovered. In clumps in cow-pastures, eroding hillsides hidden between housing developments, behind skeet-shooting ranges and oranges groves, Ziziphus is hanging on. With very low genetic diversity, small, scattered populations, and the inability to produce seedlings in the wild, Ziziphus needs all the help it can get.
However, saving Ziziphus is hard work. Evolutionary adaptations to prevent being chewed upon(aka spikiness) do not make for happy scientists. My current employers, the plant ecology researchers at the Archbold Biological Station, have tagged and followed every known individual in the wild populations and the captive populations we’ve planted in gardens and preserves. Each january, in less than two weeks, we measure and record size and flowering status of every existing plant. That includes the time wasted pulling thorns free from fingers and whining about the spiny scratching. It’s important to take the data because the plants, perhaps oblivious to their status as genetically doomed, do grow, some years profusely. Research assistants and interns crawl into the spiky mess of twigs to hunt for tags and labels that have been totally overgrown since the previous year’s census. And you can’t consider breaking off a little branch to clear a spike-free zone for your arm to work in because this is a highly endangered plant we’re dealing with here- the Ziziphus comes first.
To catch plants for the captive collections, clones are grown from root-pieces cut from healthy wild plants. Now, if Ziziphus had a long term perspective towards the survival of their own species, they might try to cooperate with biologists in this process. But instead, with each individual selfishly focused on short-term survival, Zizphus comes prepared to battle with biologists for its roots. They send a single long, thick tap root straight down, or sometimes horizontal, or sometimes down, then horizontal, then down again and to the left, often for more than a meter before branching. You can’t just cut the tap root itself- knowingly murdering this spikey endangered shrub, so you have to keep digging, with your hands like a dog, belly in the sand, head in a crown of thorns, until you find a branchpoint. A branch of about an inch thick and several inches long, that is- then you’ve hit the buried treasure. However, just to ensure that the Ziziphus get the last laugh, some of the roots, even after being chased for two or three meters, never branch.
Like most of the plants endemic to the Lake Wales Ridge, Ziziphus is adapted to wildfires. In this dry, sandy landscape, frequent lightning strikes used to set the scrub ablaze. Now, it’s frequently prescribed burns that land managers use to maintain the natural ecosystem processes. A preserve containing a population of introduced Ziziphus was recently burned so that researchers can study if the fire spurs the previously lazy plants into new growth.
Fire is also used as a tool in the quest to save the Ziziphus to eliminate competing plants like pasture grasses and invasive weeds. However, to burn all of the competitors in close proximity to the Ziziphus without harming the spiky endangered shrub itself is a thorny issue, literally. My boss advocates the cardboard box method. The grass is lit from a drip torch on one side of the shrub, while a lucky intern, in this case me, holds a large, folded cardboard box between the Ziziphus and the oncoming flames. The theory is that the cardboard will protect the
shrub, and as a added benefit, me, by diverting the flames into the surrounding grasses, an easily burnt fuel.
I know what you are thinking- cardboard boxes are flammable! This is the stupidest idea ever to light a fire all around the plant you are trying to save with merely a flammable, floppy box to protect it. But, to my surprise, the technique actually works. At least of the first hour, we carefully light the grasses around the shrubs from each side, moving the box-shield ahead of the path of the leading flames. To hold the box, and not get burnt, required me to stand in a rather uncomfortable proximity to the Ziziphus, but being stabbed seems to beat being burnt.
However, after about an hour, my cardboard defenses were breached, and suddenly my fire-protecting shield was in flames in my hands- singeing the very plant it was supposed to protect. Trying to snuff out the first burning leaves by hand just led to more spines in my hands and had very little effect on the flames. Add to this moment a sudden increase in wind that kicked the fire up a notch and sent smoke everywhere, thicker, taller grasses available for fuel, and a boss who suddenly decided to go trigger-happy, lighting several patches simultaneously. The endangered shrubs were suddenly in need of very immediate saving. You think fast in a fire: to save myself or the spiky shrub? I ended up running around, smoke-blind, stomping out the flaming grass in front of each plant I could find, only to turn and realize that imminent disaster was approaching this one, and then that one, and oh shit- that one over there in the corner, until my boss called to stop and the land manger turned on the hose to put out some of the remaining flames.
The smoke cleared and we could clearly see, even through smoke blurry eyes and running noses, the absurdity of our afternoon. What did we do at work today? We lit a very spiky endangered shrub on fire, in the name of saving it, obviously. That was several months ago. We’re going back tomorrow to
measure the survivors for growth and flowering, to see if my smoky sacrifices have helped the Ziziphus grow a little taller or bloom a little brighter.
For all that Ziziphus celata is lacking in charisma, cooperation, and reproductive ambition- in a twisted way, here in the lab, we’ve all come to love it anyway. Every new plant is a new chance to learn more about how to save them, even if it requires the miserable bloodletting process of wiring a tag to a less than friendly branch. One day, with almost 150 new plants tagged in a pasture, it was hard to believe the plant is really in danger of extinction. But in reality- my coworkers and I have been stabbed by every single Ziziphus plant known to exist on the planet, and although some days that feels like a lot of spines, it is still a plant in real trouble. Saving an endangered species isn’t always pretty, feel good-work. But, in a masochistic way, we’re rooting for these clonal masses of roots to put up more shoots, spread its spiny branches and grow.
So allow me to introduce you to one very uncharismatic
endangered species, Ziziphus celata, commonly known, to the handful of people who know it, as Florida Ziziphus. It’s a spiky shrub from the buckthorn family, growing in sandy upland sites along the Lake Wales Ridge in south central Florida. It can reach 6 ft tall- sometimes on a single upright stem, but more frequently, in a twisted, zigzagging mass of stems, branches and spines, making it difficult to tell where one plant ends and another begins. It has small, alternate leaves that are typically dark green with a shiny upper surface, and sometimes slightly heart shaped. On many older individuals, the older, woody branches are leaf-less, just gray bark and thorns.The flowers begin as clusters of small green buds along the leafless older branches. On some of the plants, these buds are the only green present. The flowers bloom for about two weeks, at some point between late December and early February, depending on environmental factors and the plants’ personal sense of humor. Thousands and thousands of the tiny flowers can bloom on the larger plants.
However, despite the sometimes prolific flowering, Ziziphus is not thriving. Stubbornly, it refuses to reproduce sexually in the wild. It is hard to save a plant that doesn't seem to be trying to save itself. Many of the known populations are made up of plants from a single genotype- they are all clones, separate stems growing up from a shared colony of roots. These clones are self-incompatible: they can not fertilize flowers and produce viable seeds together, since they share the sam
e genes. Even when several genotypes are present in a population, some of the crosses are incompatible as well, and no fertile seeds are produced. Most of the viable seeds have been produced from painstaking, painful hand-pollinations by biologists working with the captive population at the Bok Botanical Garden in Lake Wales Florida.Ziziphus is currently considered the one of the most endangered plants in Florida. It was first described from an old herbarium specimen- no one living had seen it in the wild- so it was presumed extinct. In 1987, the first of 7 known wild populations of Ziziphus was discovered. In clumps in cow-pastures, eroding hillsides hidden between housing developments, behind skeet-shooting ranges and oranges groves, Ziziphus is hanging on. With very low genetic diversity, small, scattered populations, and the inability to produce seedlings in the wild, Ziziphus needs all the help it can get.
However, saving Ziziphus is hard work. Evolutionary adaptations to prevent being chewed upon(aka spikiness) do not make for happy scientists. My current employers, the plant ecology researchers at the Archbold Biological Station, have tagged and followed every known individual in the wild populations and the captive populations we’ve planted in gardens and preserves. Each january, in less than two weeks, we measure and record size and flowering status of every existing plant. That includes the time wasted pulling thorns free from fingers and whining about the spiny scratching. It’s important to take the data because the plants, perhaps oblivious to their status as genetically doomed, do grow, some years profusely. Research assistants and interns crawl into the spiky mess of twigs to hunt for tags and labels that have been totally overgrown since the previous year’s census. And you can’t consider breaking off a little branch to clear a spike-free zone for your arm to work in because this is a highly endangered plant we’re dealing with here- the Ziziphus comes first.
To catch plants for the captive collections, clones are grown from root-pieces cut from healthy wild plants. Now, if Ziziphus had a long term perspective towards the survival of their own species, they might try to cooperate with biologists in this process. But instead, with each individual selfishly focused on short-term survival, Zizphus comes prepared to battle with biologists for its roots. They send a single long, thick tap root straight down, or sometimes horizontal, or sometimes down, then horizontal, then down again and to the left, often for more than a meter before branching. You can’t just cut the tap root itself- knowingly murdering this spikey endangered shrub, so you have to keep digging, with your hands like a dog, belly in the sand, head in a crown of thorns, until you find a branchpoint. A branch of about an inch thick and several inches long, that is- then you’ve hit the buried treasure. However, just to ensure that the Ziziphus get the last laugh, some of the roots, even after being chased for two or three meters, never branch.Like most of the plants endemic to the Lake Wales Ridge, Ziziphus is adapted to wildfires. In this dry, sandy landscape, frequent lightning strikes used to set the scrub ablaze. Now, it’s frequently prescribed burns that land managers use to maintain the natural ecosystem processes. A preserve containing a population of introduced Ziziphus was recently burned so that researchers can study if the fire spurs the previously lazy plants into new growth.
Fire is also used as a tool in the quest to save the Ziziphus to eliminate competing plants like pasture grasses and invasive weeds. However, to burn all of the competitors in close proximity to the Ziziphus without harming the spiky endangered shrub itself is a thorny issue, literally. My boss advocates the cardboard box method. The grass is lit from a drip torch on one side of the shrub, while a lucky intern, in this case me, holds a large, folded cardboard box between the Ziziphus and the oncoming flames. The theory is that the cardboard will protect the
shrub, and as a added benefit, me, by diverting the flames into the surrounding grasses, an easily burnt fuel.I know what you are thinking- cardboard boxes are flammable! This is the stupidest idea ever to light a fire all around the plant you are trying to save with merely a flammable, floppy box to protect it. But, to my surprise, the technique actually works. At least of the first hour, we carefully light the grasses around the shrubs from each side, moving the box-shield ahead of the path of the leading flames. To hold the box, and not get burnt, required me to stand in a rather uncomfortable proximity to the Ziziphus, but being stabbed seems to beat being burnt.
However, after about an hour, my cardboard defenses were breached, and suddenly my fire-protecting shield was in flames in my hands- singeing the very plant it was supposed to protect. Trying to snuff out the first burning leaves by hand just led to more spines in my hands and had very little effect on the flames. Add to this moment a sudden increase in wind that kicked the fire up a notch and sent smoke everywhere, thicker, taller grasses available for fuel, and a boss who suddenly decided to go trigger-happy, lighting several patches simultaneously. The endangered shrubs were suddenly in need of very immediate saving. You think fast in a fire: to save myself or the spiky shrub? I ended up running around, smoke-blind, stomping out the flaming grass in front of each plant I could find, only to turn and realize that imminent disaster was approaching this one, and then that one, and oh shit- that one over there in the corner, until my boss called to stop and the land manger turned on the hose to put out some of the remaining flames.
The smoke cleared and we could clearly see, even through smoke blurry eyes and running noses, the absurdity of our afternoon. What did we do at work today? We lit a very spiky endangered shrub on fire, in the name of saving it, obviously. That was several months ago. We’re going back tomorrow to
measure the survivors for growth and flowering, to see if my smoky sacrifices have helped the Ziziphus grow a little taller or bloom a little brighter.For all that Ziziphus celata is lacking in charisma, cooperation, and reproductive ambition- in a twisted way, here in the lab, we’ve all come to love it anyway. Every new plant is a new chance to learn more about how to save them, even if it requires the miserable bloodletting process of wiring a tag to a less than friendly branch. One day, with almost 150 new plants tagged in a pasture, it was hard to believe the plant is really in danger of extinction. But in reality- my coworkers and I have been stabbed by every single Ziziphus plant known to exist on the planet, and although some days that feels like a lot of spines, it is still a plant in real trouble. Saving an endangered species isn’t always pretty, feel good-work. But, in a masochistic way, we’re rooting for these clonal masses of roots to put up more shoots, spread its spiny branches and grow.
Photos by Lauren Sullivan. Thanks to Carl Weekly and the rest of the Archbold Plant Lab for introducing me to Ziziphus and for finding the humor in these long, spiky days in the field.
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