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Climate and species are a-changin’

8 Oct

This summer was a perfect example of environmental changes. In the northern states, some waterfowl species never migrated south last fall, and this spring’s surveys revealed that some birds migrated north earlier than normal. Conversely, milkweed (Asclepias spp.) emerged one to two weeks early and migrating monarch butterflies arrived two to three weeks late in all the northeastern states. Areas in a few northeastern states were stricken with a historic “100-year or more drought.” On the other hand, many areas in the semi-arid southwest experienced historical devastating floods.

Is this a fluke? Or is this the new norm? Perhaps somewhere in the middle, but more likely these weather and climatic changes are the ‘new normal.’  The events and data support that assessment.*

How do living organisms respond?

Published studies by biologists have been documenting the impact of climate change on the environment, especially species that are adapting and not adapting. We can learn about impacts on organisms  by examining changes in cyclic and seasonal natural phenomena of plants and animals in relation to climate. These seasonal changes and cycles are known as phenology. Noting the times of year that specific plants bloom, or when birds migrate are two examples. Comparing the phenology of many species over a period of time can reveal informative clues on how changes in climate may affect them. Many studies along this model of investigation demonstrate that the living environment is indeed impacted.

United Kingdom researcher Stephen Thackeray(1) and his colleagues analyzed the phenology of a wide range of species. They used 10,003 phenological data sets to determine if and how much species’ phenology have changed over a minimum of 20 years. The analysis revealed that phenology has shifted in unequal rates in different species groups. Thus, climate change leads to disruptions of the phenological match between species, which often impacts ecological relationships.

Another question the researchers asked was how sensitive events in their life cycles are to the two most common variables in climatic change: temperature and precipitation. Both variables have changed in an uneven process over the flow of seasons. How does this impact species relationships? Some periods of the year have warmed faster than others, which may affect two interrelated species with equal temperature sensitivities but at different times. This could shift their phenological events at different rates and cause a mismatch in their relationship.

For example, milkweed plants emerging and flowering much earlier than normal resulted in sub-optimal conditions for the late-arriving monarch butterflies to use the plants for breeding. Additionally, the persistent hot and humid weather in the northeast could impact monarch larva (caterpillar) by either accelerating or arresting development.

trophic-pyramid

Trophic levels

The study authors also discovered a difference of sensitivity to temperature variations at different positions of the food chain (referred to as trophic levels). Species at different levels did not differ in the time of year at which they were sensitive to annual variations in temperature. But they did vary in how sensitive they were.

 

Species in higher levels of the food chain (the secondary consumers) are less sensitive to temperature changes than species at the bottom (the producers and primary consumers). These species are twice as sensitive to temperature changes than upper level species. Secondary consumers are also less sensitive to precipitation variations.

The authors then combined the species sensitivities with a future climate scenarios. They forecast that primary consumers -birds, insects, small mammals, etc- will shift the timing of their phenological events by twice as much as will species at other levels of the food chain. One reason their response varies is because species at different tropic levels respond differently to exactly the same temperature cue. Species respond differently to temperature during various times of the year.

The above example of the milkweed and monarch butterfly mismatch could impact the breeding success and thus population numbers of the butterflies. Both species have different physiological mechanisms that determine their phenological events and use different cues to determine their timing. Although these cues will be correlated to some extent, the cue used by the consumer -in this example, the monarch butterfly- is less reliable than that of the the plant they rely on. This cue unreliability in the consumers may mean that they will evolve with less temperature sensitive phenology than those species at the trophic level they rely on.

Ecologist Marcel Visser (at Netherlands Institute of Ecology) calls attention to moving from conventional two-species interaction research to a more holistic approach: investigating the effects of climatic change on the entire food-web. In a review(2) of the Thackeray, et al. study, Visser additionally proposes that impacts by phenological mismatches could be buffered by other mechanisms in their ecosystems.

To help us understand the consequences of phenological mismatches and thereby form predictions, he proposes questions that should be considered in studying changes in climate changes and relationships:

How are the strengths of the links in a food web affected by phenological mismatches? What happens if the phenology of species at one trophic level shifts more than that of species at another? Does this lead to the loss of some links and the formation of others? Does this destabilize the web? Such analyses would be a stepping stone from studying the phenological shifts of species to understanding the effects of
climate change on ecosystem function.(2)

dscn2300-m

Stink bug preys on larva.

An example for a holistic ecosystem approach is field observations (my own and in the literature) that have suggested that as prolonged temperatures increase, depredation and parasitism of monarch larvae and adults increase. Is this a function of differences in phenology of  monarchs and its predators, or changes in all vegetation and species interactions (a complex of one or more phenological overlapping and mismatches)  in the habitat? Do temperature mismatches in other members of the monarch habitat increase risk or rates of depredation?

One research team suggested that migration of monarch butterflies may have evolved as an adaptation to decrease depredation and parasitism in their breeding habitats. If monarch adults were to delay or ignore cues to migrate because of changing climate, how would that impact their overall population?

Adding to the complexity, climate sensitivity in species is not fixed. Phenological mismatches can lead to selection on the timing of phenological events. Resilience to environmental challenges can alter phenology, but over time can also result in genetic changes to sensitivity, thereby fixing phenological changes. Conventional theory on temperature range sensitivity of monarch adults and larvae states that it quite narrow. However, some observations(3) of their coping mechanisms with prolonged high temperatures in the Pacific Northwest sub-population questions if this sensitivity range is more flexible than conventional thought, or if this could be a developing adaptation.

Some researchers are already investigating genetic changes accompanying phenological adaptations to climate change (e.g. genetic alterations in melanin associated with plumage and physiology in European owls that have adapted to changing ecosystems). Such complex studies must be conducted to forecast the impacts of climate change and phenological responses and ecosystem function.

Research by Thackeray, Visser, and other colleagues demonstrates that long-time series of data are essential for such investigations. They also applaud and encourage professional and citizen scientists to continue collecting and submitting observations to add to the data pool. As Visser commented, “The additional advantage is that observing phenological shifts in, sometimes literally, your own backyard drives the message of global climate change home.”


(1) Thackeray, SJ, et al. “Phenological sensitivity to climate across taxa and trophic levels”. Nature 535, 241–245 (14 July 2016)
(2) Visser, ME. “Interactions of climate change and species”. Nature 535, 236–237 (14 July 2016)
(3) Anecdotal observations by Dr. David James, Washington State University entomologist, in central Washington and myself at Malheur National Wildlife Refuge, eastern Oregon.

* The main difference between weather and climate is time. Weather is the atmospheric local events over a short period of time.  Climate is an average of the weather over much longer time in a region or globally. Sure, we can agree that weather and climate is cyclic, with highs and lows historically up and down. Also, a few episodic variances from the average can be expected.  But climate does not vary as greatly as weather. The trends clearly demonstrate that climate is changing. Modern paleoclimate technologies can now add to the 70-year human records of climatic changes, both which confirm that climate change is a reality. Those changes have accelerated, more than any other equal span of time in historical evidence.

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Nature in Photography

6 Feb

A week or so ago on FaceBook I was nominated by two friends to participate in the #challengeonnaturephotography meme. Although I rarely participate in these memes, the thought “Why not?” prompted me to give it a try. The protocol is to post a nature-themed photograph, include the hashtag, give kudos to the friend that nominated you, and then nominate another friend in the caption.

I played by the rules for three days. Then life got in the way (long days in the field), and I got lazy. I posted when I had time, dropped the official hashtag, the nominators, and ran out of FB friends to nominate. I keep my FB friends to a relatively small number (up to 50 now!), and friends who are into photography have already participated once or twice.

Now I submit a story with the photograph instead. Why? Because photography to me is a storytelling medium. Today’s photograph is a glimpse into the secret lives on the ‘little people’.

Nearly every day for three months last summer, I was privy to an entire world few of us see in depth and detail. I felt like a giant studying, learning, and enjoying a network of soil, water, plants, and insects……….at their level. Sometimes I was so giddy with childlike delight, I forgot who and what I was. And I was full of anger and intense sadness when part of this magical world was destroyed by humans. That, too, was a lesson I won’t forget.

Revealed below is a monarch butterfly larva and several cobalt blue beetles all ‘doing their thing’. They use milkweed as a common food source. Yet they tolerate each other. I have watched members of both species consume leaf material, side by side without conflict. Here, two beetles are copulating, undisturbed and unfettered. While the monarch voraciously chows down, preparing to form its chrysalis. This, however, is only one tiny window into the lives that live in the ecosystem in which I immersed myself.

Most nature photography depicts landscapes of empty agents and actors. Or portraits of animals, still and silent in pose like a person sitting for a photograph. To me this is an injustice to the inhabitants of the landscape as they live out their drama and narratives in those spaces. Few ‘nature’ photographs reveal the complex interrelationships within the landscapes and with their fellow animals. They fail to show the communities of life in places other than within our own human preconceptions and expectations. As if we strive to capture and show only a snapshot in time and space that suits what we want to see.

In addition to the beauty, the silence and solace depicted in landscape and wildlife portrait photography is a dynamic world of creatures living their lives just like we do. The drama, the beauty, the good and bad, birth and death, at every level; from micro to macro. There are stories out there that are not of our own.

And we can learn from them: About their lives, their interactions with each other and how we interact with them. We can even learn about ourselves.

Think about that the next time you are out in the natural world. Take time to observe before you press on that shutter release button. You never know what you might find.

image

Fifth instar monarch larva and cobalt blue beetles on showy milkweed.

Where does one organism end? The art of seeing.

31 May

It began with my father telling me as a child, “If you want to talk to an animal, you have to learn their language.” So I started to learn and talk to animals. In their language. Decades later when I was in undergraduate university struggling through chemistry class, he again helped me to understand. During a phone conversation we discussed chemical bonding, which I was having trouble grasping. Again, “Think like electrons and you will see how they attract and repel. And that will illuminate how weak or strong they are in varying conditions and in relation to their neighbors.” It started to all make sense and I ended up loving chemistry.

When water from spring thaws threatened to invade my cabin where I lived in the woods of Maine, an old-timer on the farm up the road told me to ‘think like water’ and work with it rather than against it. Every spring found me constructing meandering ditches to channel water away from the cabin foundation. It became a game and it was like dancing with old friends (yes, we even had conversations).

Another time, Larry helped me build a dormer onto a loft in the cabin for a spare bedroom. He taught me much about carpentry and literature. (I never did learn why a man with three degrees in English and literature chose to become a carpenter.) While working where the dormer walls integrated with the main roof, I asked how to prevent the roof from leaking. It was déjà vu when he replied, “Think like water and work with it.”

A few years later a local trapper mentored me on tracking animals. By this time I already began infusing into my everyday perception the phenomenology of weather, plants, and soil. The old trapper was like the Dali Llama of animals and birds. The only organism I lacked any ability to ‘think like’ was human beings. Back then I had no interest, nor patience.

It was months before I was ‘allowed’ to look at animal tracks and relate them with a species identification. My first lessons were sitting or standing still, for hours. Silent. Listening. Observing. Letting go of any obtrusive thoughts that might separate me from my surroundings. I learned to meld into the tree I sat against, to become the bush that I stood in, and to move silently. I learned to appreciate silence. Not only in the woods, but also in my own habitat. It was not unusual for me to not see or talk to another human for a week or two.

I could be ‘invisible’.

Trumpet swans and cygnets

I became highly sensitized to the weather. I could smell and feel weather changes long before they arrived. Wind patterns in the upper or lower canopies of trees informed me when storms might be coming in, and where they came from. Animal movements were also predictive.

Birds and  animals began to approach me rather than flush away. In the winter, a mink was a common visitor to the porch of the cabin. It would approach and watch me as ardently as I watched it while sitting on the outdoor steps. At one point, it would come near my feet and groom itself or eat a caught prize.

I learned patience with the changes in the natural world around me, and the creatures that shared my space. I watched their behavior and learned how they interacted with their surroundings. We all learned to inhabit the same space with a mutual respect. They observed me as much as I observed them. And it was a smooth transition to learn how to piece together the stories of their tracks and sign as much as they did the same with me. It was not uncommon for me to spot a deer or badger that had been following me as much as I had been following them.

A quarter of a century later, and many chapters of life changes, I found myself doing the same last week. Every day I drove the cramped little truck down the chunky gravel road to park the truck so that it would not block visitors or other staff on the refuge. Sitting on the tailgate, I removed my regular boots and pulled on the chest waders. The field vest was the last item; heavy, with so many filled pockets it was like a weighted vest, binoculars hanging on my chest. And then wade through the canal waters to go out into a world that few really see. By that, I mean ‘see’.

My focus was surveying vegetation in the marshes and  transition zones from wetland to dryland, even the sagebrush steppe. I searched for plants (other than grasses and sedges) that were emerging, budded, and flowering. The prize was the milkweed species (Asclepias spp.). However, I also searched for plants that might serve as nectar sources for Monarch butterflies. Because of the dearth of data for Monarch butterflies, the milkweeds and nectar sources in SE Oregon, my search was wide open. I decided to document all of the forbs and shrubs that might be candidate nectar sources, as well as any milkweed plants.

Red-winged blackbird.

Over four days I covered a large field accumulating a preliminary database of plant phenology that has been missing from this part of the refuge. However, my time out in the marshes also provided an opportunity to observe a variety of  birds and mammals within their own private lives. I learned many new bird calls, observed birds interact with each other and their interactions with me. Twice I was warned away from specific locations by female northern harriers, probably too close to their nests. Other times, I watched red-winged blackbirds dive bomb the same harriers, one blackbird even riding on the back of a harrier until it was out of range.

One early morning I quietly came upon two young black-tailed bucks as they grazed grass. While I froze in place, they watched me. Our eyes met, and when I blinked, they blinked. I could see them relax, and even when I slowly moved myself several feet away, they were not perturbed.

During these days, I found myself thinking, ‘Think like a butterfly’. Or ‘Think like this plant’, and ‘Think like that/those bird(s).’ As my father and others in my past taught me, I tried to look at their world through their eyes, their noses, their mouths, and their ears. Even their roots and leaves. Our lives and being overlapped.

At times I forgot what species I was. I became a part of the whole system. I found myself adopting their same behavior when a vehicle drove down the gravel refuge road: being still and blending in. Becoming ‘invisible’.

I began to ‘see’ and become a part of them.

Sagebrush Galls: Medusa!

16 May

“How galling!! The audacity of this insect making a home in me!”

True; no matter how one organism looks at it, it’s annoying. The word ‘gall’ originates from Middle English (~ 900 A.D) and refers to bile, the bitter fluid from the gall bladder. The figurative word ‘galling’ refers to irritating, offensive, audacity and very annoying behavior.  But how did an abnormal plant growth acquire the same name, gall?

We may never know.

As a child roaming the woods and wild fields, I would often collect tree and shrub leaves and twigs that had protruding bumps in a variety of shapes.  I wondered what these odd shapes were, but it never occurred to me that they might be injurious to the plant, or even malicious at all. Nor did I know then how they were formed.

One day while wandering in the field I found a particularly large growth on the stem of a shrub. Pulling out my magic little ‘looking glass’ (pocket magnifier), I watched half a dozen little translucent bugs crawl out of the ball-shaped growth. In a short time, these bugs acquired color and their wings unfolded away from their bodies. I wondered if the abnormal-looking ball of green was a home for these bugs, and only much later did I learn they were called ‘galls’. And from then on, anytime a person uses the word ‘gall’ or ‘galling’, all I can think of are these appropriated plant cells that serve as a home for small insects.

Five decades later and I’m still fascinated by galls!

Here in the high desert of the Great Basin, galls are common on sagebrush, the most dominant plant. What surprises me is the morphological variety of these galls: the colors, shapes and sizes. So, like the child I was (and probably still am), I have been collecting samples to take back with me, as well as photographing them.

What are galls, anyway?

Galls are an abnormal plant growth induced by various parasitic organisms (1), usually insects. These latter galls will be the focus of a series of posts here as I find examples.

Galls serve as ‘incubators’ for developing insects where they gain nutrition and protection from environmental conditions and predators. Some galls are colorful and easily distinguished from the other plant material. Some are wooly, some round and colorful like tiny plums, some are lobed, and others have spiky protuberances.

Gall-inducing insects are usually species-specific and sometimes tissue-specific on the plants they parasitize. Galls can be found on leaves, stems, shoots, flowers and roots. Combined with gall morphology, these traits will often help to identify which insect is associated with them. However, identifying the insects inside will be the confirmation.

These insects manipulate and exploit the chemistry and physiology of plant tissue to their own benefit and development. Accordingly, galls act as physiological sinks for mobilized plant resources, mostly as nutrition for larvae. Fungi sometimes grow on the interior of the gall surface on which the larvae feed.

Like little houses, galls physically serve as protection from the sun, wind, rain and snow. In fact, because the gall-forming insects control gall formation so well, galls are commonly referred to as their extended phenotype. However, several predatory insects have also adapted to this system by inserting their own larvae inside galls. Then a battle for who eats whom ensues until maturation of one or both species. It’s not uncommon to have more than one species of insect emerge from a gall, but only one of those species induces galls.

Protection is one explanation for the high levels of compounds, such as phenolics and tanins, found in many galls. This is considered a defensive gall trait, protecting the gall against natural enemies outside. Thus, in addition to serving as a nutrition sink and physical protection, some galls have a natural chemical defense.

Sagebrush gall midges

Like any plant, it’s an insect-eat-leaf world out there for sagebrush. Of the 237 species of insects that are associates of sagebrush, 42 are gall-forming insects. Of those, the most predominant are Cecidomiidae, or gall midges. They are a small family of tiny flies that are associated with gall induction.

The most abundant gall midges found on sagebrush are of the Rhopalomyia genus. Although there are 32 species, not all may be present in the same location and area. A recent study suggests that land use or local abiotic conditions may greatly influence the diversity of gall midges.

The adult midges lay eggs in the sagebrush stem tissue. The eggs hatch and the larva secrete saliva into the plant. Compounds in the saliva alter the growth of the injured plant cells and the tissue produces a swelling, or gall, around the young insects. However, the size, shape and color of the developing gall are typically specific to the gall midge species. On the other hand, one species unusually induces a wide range of gall morphologies.

Medusa Galls

During a recent camping trip on Steens Mountain in SE Oregon (and bordering the Refuge), I found many specimens of Medusa galls (Rhopalomyia medusa) on Big Sagebrush (Artemesia tridentate). As seen in the photograph, these galls are composed of numerous leaf-like structures. Looking at the long miniature leafy structures, it’s easy to see how this gall was called “Medusa”.

Medusa Gall on Big sagebrush

The galls develop in October and rest during the winter. They reach full size in the following spring and adult midge flies emerge in April or May. When I was there, May 9-11, the galls were intact with no sign of emergent flies. Considering the elevation (7,300 feet) where I was hiking, patches of snow were common and the climate was barely spring-like.

Authors of a study (2) sampled arthropod diversity on sagebrush in two ecosystems, one surrounded by dryland agriculture and the other area protected from agriculture and significant human use. Their data suggests that diversity of gall midges is highly variable with the dynamics of arthropod-sagebrush interactions and the sagebrush ecosystem. Interestingly, R. medusa was one of a few species that served as an indicator species in low human impact sagebrush habitats. A good description of where I found the many specimens on Steens Mnt.

So, do these galls negatively affect the sagebrush? We will examine that question in a later post!

1. Some bacteria species can also cause galls. This was my first introduction to galls in undergraduate university. Crown gall (Rhizobium radiobacter, formerly known as Agrobacterium tumefaciens) is the textbook and lab example used in plant pathology and lab classes. It is also a common tool to teach Koch’s Postulates. Soil bacterium inserts a small segment of DNA (T-DNA) from a plasmid and into the plant cell. This DNA encodes for genes that produce a plant hormone, auxin (indole-3-acetic acid), via a special pathway that is not used in most plants. Thus the plant has no molecular means of regulating the production of the exocrine hormone. The T-DNA also signals extra production of a group of plant hormones called cytokines, which are involved in cell division. These hormones are responsible for the tumor-like growth of plant tissue and form the galls.

2. Sanford, M.P., Huntly, N.J. 2010. Seasonal patterns of arthropod diversity and abundance on Big sagebrush, Artemisia tridentata.  Western North American Naturalist, 70(1): 67-76.

It depends!!

19 Mar

funny-owl-i-have-no-idea-whats-going-onShould burns take place in spring
Or wait for autumn rain?
Would baiting help or hinder?
Can owl chicks live through flame?

‘I dunno,’ we had to answer.
‘Not sure, can’t really say.
Needs further replication
Might vary day-to-day.’

PhDs require devotion,
Long days with no weekends
But the ultimate conclusion seems
‘Umm, well, it depends.’

– excerpt from post, ‘My Grand Conclusion‘, on zoologist Bron’s blog, Working on the Wild Side

 

The two of us answered in unision….. “It depends.” And looked at each other with a knowing smile.

A retired couple asked for information on where to go to see this bird and that bird. Husband asked for specific details: what species, what location, what time. He was dissatisfied with my answers, including “They were seen here yesterday morning, and there yesterday afternoon, and at this location this morning, but they may be anywhere. They don’t send us memos on when or where they go.”

When asking for exact details on how to get to ‘Point A’ from ‘Point B’ (a distance of 125 miles), my explanation of various options of traveling from Point A to Point B resulted in visible upset. His wife gently reminded him that they aren’t in a hurry and he might enjoy experiencing different things along the way. Her comment was met with a hand wave, pointing at a map, and listing what he expected to see, do, encounter, etc. He wanted no surprises.

“If something changes, if we stray from the map, it will be an adventure!”, said Wife.

“No! No surprises, and I don’t like adventures. Adventures mean poor planning,” Husband responded. “How long will it take to get to ‘Point B’?”

Wife and I replied simultaneously, “It depends!”

I looked at them both and then asked Husband, “Are you a mathematician?”  Eyebrows went up and he said, “Why, yes! How did you know?”.

“A strong aversion of risk and uncertainty,” I responded. Wife  returned my smile.

“Oh my God, are you a biologist, too?!” Husband asked with raised eyebrows and looking like he was stuck in between two conspirators.  By that time, all three of us were laughing.

Third Law: It Depends!

My First Law, apologetically borrowed from The First Law of Thermodynamics (aka ‘You can’t win’), states that where there’s a positive, there is a negative. And this is related to My Second Law: ‘Everything is relative’. ‘Positive’ and ‘negative’ are relative to the perspective of that which observes or experiences the action/reaction, which depends on time, place and being. (Note that the Second Law of Thermodynamics is ‘You can’t break even’. See blog post linked above.)

I think you can see where I’m going.

My Third Law is ‘It Depends’. If anything I have learned in biology and ecology remains constant, it is ‘It depends.’ For the person who demands or insists on a life or reality of ‘Yes’ or ‘No’, you will either be disappointed or live in perpetual denial. For life is not simply black and white. A vast area of gray reside in between.
Further reading:
The typical ecological answer – it depends“, blog post by oikosasa. Website: Oikos: Synthesizing Ecology.
“Which species is best for their host marsh cordgrass? Fiddler crab or mussel? The answer is – it depends”

 

 

Donkey or Burro??

3 May

They are the same animal. The only difference is the time frame and location in which the two names came into usage. On the other hand, before either of these words were ascribed to this cousin of the horse, it was called an ‘ass’. And it still is in most countries. What’s the difference?

Asses, zebras, and horses are members of the genus, Equus, which is from Latin for ‘horse’. DNA recovered from a fossilized horse bone (700,000 years old) places their common ancestor to be between 4.0 and 4.3 million years ago. Although the domestic horse and the zebra species have gone through several intermediates on the evolution tree since then, the ass has not. So how did the ass become a donkey or burro?

The wild ancestor of the domesticated donkey was the African ass, Equus africanus, which lived in the deserts of northeastern Africa. Members of the latter were domesticated as work animals around 3,000 B.C. in Egypt and Mesopotamia. In the late 18th century, the English name ‘donkey’ came into use, probably formed from the word ‘dun’, referring to the dull gray-brown color of the animal, and the suffix ‘-key’ to rhyme with ‘monkey’. However, in other areas of the globe, the animals were still referred to as ‘asses’.

Because it can carry heavy loads and cope with hot and dry conditions, the donkey became one of the most important domesticated animals. They were also favored for their easy maintenance; they are very adept at foraging for their own food. These traits, along with their toughness and adaptability, able them to thrive in harsh arid surroundings. Consequently, the Spanish found them invaluable during their explorations and establishment of settlements and missions. And it was the Spanish that brought them to the American continents during the 1400 and 1500’s along with their cousin equines, the horse.

Spanish explorers introduced the donkey to the subtropical deserts and semi-deserts of northern Mexico and the American Southwest during the 1500’s. The animal began to be known in Mexico as ‘burro’ in the early 19th century. Burro probably derives from the Spanish ‘burrico’ and the Late Latin ‘burricus’, meaning “small, shaggy horse.” Consequently, the animal may be called ‘donkey’ or ‘burro’ depending on which side of the border you are on. And an ‘ass’ if you are on the other side of the ocean.

Regardless, all three – donkey, burro, and ass – are the same genus and species: Equus africanus. On the other hand, the International Commission on Zoological Nomenclature ruled in 2003 that the domesticated ass, aka the donkey/burro, may also be classified as E. africanus asinus, simply because the domesticated animal was classified and named before the wild ass. Consequently, one will find the donkey/burro with either scientific name, whereas the wild ass will be associated only with the one. Although the colors and a few other small appearance details may distinguish the wild and domesticated ass, they are genetically the same animal.

Burros in Big Bend

Myths and legends abound relating stories on how the burro came to the Big Bend area. Without doubt, the animals arrived by many means and over many centuries. With the Spanish explorers and conquerors, and Mexican settlers, came the burros into the American Southwest. They were tough as nails, adapted to the arid and undeveloped area, and needed little in the way of husbandry efforts. They were the perfect work beasts.

Burros in Big Bend (photo courtesy of Rick Ethan, Terlingua)

Burros in Big Bend (photo courtesy of Rick Ethan, Terlingua)

Later came the prospectors and miners of the 1800’s and early 1900’s with their burros. As in Mexico, they became the favored beast of burden and they could almost fend for themselves. The animals hauled wood for railroads and fuel, ore from the mines, and grain for their human masters. Burros were also bred with horses for their hardy offspring, mules. These animals were used to haul stagecoaches and serve as supply trains for the Army during the early 1900’s.

Historically, burros were not corralled or tethered in the same way horses were. The usual practice was to leave them to forage on their own and then they were rounded up when needed. However, some escaped or were never rounded up. Many outlived their owners. They eventually roamed on their own and became ‘feral.’

Newspaper reports of burros abandoned by farmers can be found in the last several years. The series of droughts throughout the Southwest have prompted farmers to drop off burros in roadside pastures or other rural areas. These and other feral burros form small herds or join other herds. Escaped burros from across the border often join these herds and their population increases quickly. Burros are not heavily preyed upon and can live up to 40 years, so their population can double in less than three years if conditions are good.

An adult burro averages about five feet tall at the shoulders and weights about 350 pounds. It eats about three tons of food a year: grasses, forbs, browse. Their foraging can greatly impact the ecosystem that evolved and came into balance long before this non-native animal was introduced. Because of their large size, number and adaptability, the burro can be a problem for land managers in arid and semi-arid areas. If their numbers remain unchecked, their impact destabilizes the ecosystems they inhabit. Additionally, accidents on the roads are becoming more common. Burros aren’t motivated to move out of the roads and drivers crashing into wild burros.

Most feral burros live on public lands, especially the vast stretches of BLM land, national parks and wildlife preserves. The animals are not native to Texas or to the Americas. Nor are they a threatened and endangered species, or even of ‘heritage’ herds. Most of the animals have been abandoned from nearby ranches, many crossing the border from Mexico, and their offspring increase their populations.

Several national parks, such as Big Bend and Grand Canyon National Parks, had an early policy of hunting and shooting feral horses and burros to restore the lands to pre-human ‘wildness.’ In response to public outcry of mass killings, most of the national parks arranged for the capture and relocation of feral burros from their landholdings. However, they seem to return or replenish their numbers from mysterious origins.

Burros, donkeys and asses are the same animal. But, as for how they got here, you can choose your favorite legend.

Live Chat: Protecting the World’s Predators

8 Jan

Recent organized kill parties of coyotes and wolves have circulated on social media like an epidemic virus. Large coyote hunts in New Mexico and Idaho, private and state-organized hunting events of wolves in several western states, and the recently publicized role of the federal government ‘Wildlife Services’ in blanket extermination of all large mammalian predators, demonstrates and increases awareness of our attitudes and behavior toward predators in our ecosystems. Many issues are layered at all levels: scientific, public attitudes, industry (ranching), and public policy.

Historical and recent approaches have demonstrated that simple education is insufficient and ineffective. Underneath current attitudes of predators and predation is an old and ingrained hate and fear of the ‘top of the food chain’, except for one species: Homo sapien. The roots are cultural, historical, social, psychological and religious (yes, it’s roots in part come from religious doctrine). Until we can rid the demon inside us, so to speak, reception to scientific evidence for the beneficial role of predators, and attempts at reasoning and rational discussion on how to live with other natural predators (which, in all biological sense, humans are the ultimate predator) will fail.

This Thursday, January 9th, Science Magazine online hosts a live chat with guest speakers: an ecologist and an environmental scholar, also a lecturer in environmental ethics. Participants can pose questions to the host and guests.

“What is it about large predators that makes them so important in ecosystems? How can we ensure their continued survival in a world with increasing human encroachment? And what would a world without predators look like if we fail?”

Join in on Thursday at 3 p.m. EST on the linked page for a live video chat. Leave questions for the guests in the comment section below the announcement. Readers here are invited to make comments here on this blog page for possible discussion, too.

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