Bison Ecology

About the artist, Wes Olson; Wes Olson’s thirty-five years of working intimately with bison―and featuring Johane Janelle’s stunning photography―

The Ecological Buffalo: On The Trail Of A Keystone Species  is a story that takes the reader on a journey to understand the myriad connections this keystone species has with the Great Plains.  About 300 pages of Bison Ecology, easy-to-understand information about our bison and their role in the ecosystem, along with the most incredible images and drawings to guide us through this journey of understanding. (5 Stars) 

Snippet: The mere mention of the buffalo instantly brings to mind the vast herds that once roamed the North American continent, and few wild animals captivate our imaginations as much as the buffalo do. Once numbering in the tens of millions, these magnificent creatures played a significant role in structuring the varied ecosystems they occupied. For at least 24,000 years, North American Indigenous Peoples depended upon them, and it was the abundance of buffalo that initially facilitated the dispersal of humankind across the continent.

Copyrights & Credits

Wes Olson was recently highlighted in a Square Sheep Documentaries production about bison. He discusses the historical aspects, contemporary movements of bison herds, and their present-day existence, focusing on their ecology and familial structure. “Bison” film.


Ecological Buffalo
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What’s inside: 

 ‘This book represents the culmination of several decades spent among the bison of North America. In our travels throughout the historical range of plains and wood bison, my wife, Johane, and I have been captivated by the relationships that bison have with the other species they share space and time with. ‘


Introduction: ‘For more than thirty years, Johane and I have been captivated by all things buffalo. Johane is enthralled by their charismatic beauty and the stunning photographic opportunities they present. I became enamored with buffalo because, when I first met them, I knew nothing about them. For both of us, our journeys along countless buffalo trails have taken us to some of the most exquisite landscapes North America has to offer.

As we walked the path of the buffalo, we slowly began to see the relationships buffalo have with the species who share their landscapes. In doing so, we began to pay attention to the things we saw. For the first time we actually “looked” at a bison wallow, and when we did, we could read the signatures of other species as they stopped to sign the prairie guest book on the dusty pages of a wallow. “



Chapter 1 The Great Slaughter

On a visit to Yellowstone, we of the thirty-three states where they once found this lone bull, and he seemed to us to be representative of the great slaughter that took place in the mid-1880s.

It may seem odd to begin a story about bison at the grimmest point in their history, but it helps to place the story of their ecological role in perspective. 

Most people today know that there was a time when bison roamed North America in vast herds, and some may know that at one time there were an estimated thirty to sixty million plains bison. But few understand the impacts this many bison had on the ecosystems they lived in, and most do not understand how the removal of bison from the land influenced the interconnectedness between these other species and bison.


Chapter 2 Interconnected Ecosystems

Vast flocks of snow geese and sandhill cranes migrate tremendous distances on their annual migrations, where they depend upon connected ecosystems. North America has been divided into 182 different ecoregions, ecologically and geographically defined areas that cover relatively large areas of land or water, and contain characteristic, geographically distinct assemblages of natural communities and species. The biodiversity of flora, fauna, and the local ecosystems tends to be distinct from that of other ecoregions. Of these 182 ecoregions, bison once occupied at least forty-six. In each of these, the vegetation and wildlife species that interacted with bison were different; but in one way or another, all were influenced by the presence of bison, and later, by their absence.



Chapter 3 Bison As A Keystone Species

Wood bison in Canada’s Wood Buffalo National Park, in Alberta, graze a boreal forest meadow. Like the far more numerous plains bison, wood bison performed critical roles as a keystone species across northern Canada and into Alaska. Their population probably never exceeded 200,000 individuals, and at their lowest number, only 250 remained.
The term “keystone” has its origin in stone masonry and its use can traced back to 1000 to 500 BC in the stone arches created by the Romans.1 This stone is the wedgeshaped stone at the apex of a masonry arch. It is the final stone placed during the construction of the arch and locks all the stones into position, allowing the arch to bear weight. Without this keystone, the arch cannot stand, and the entire structure collapses.



Chapter 4 GrasslandsCan a more quintessential scene exist than that of these two bison calves, stark against the smoke of a grassland fire? We were searching for sage grouse when we came across a small herd in Grasslands National Park, Saskatchewan. We didn’t find the grouse, but this classic prairie scene remains etched in our memories.

On the continental scale, there are three principal types of grasslands: the tallgrass prairie, mixed-grass, and short-grass prairies. To the west of Montana, in Idaho, Washington, and Oregon exists a fourth grassland type, the Palouse prairie, and along the east slopes of the Rockies, the foothills fescue grasslands.



Chapter 5 Bison And Seed DispersalA large, barbed seed of wild by the plant, and wind all tend to deposit licorice adhered to the face of this bison cow as she grazed across the prairie.

If you have ever walked across a late-summer grassland, there is a good chance you will have seeds stuck to your pant legs.
A large, barbed seed of wild licorice adhered to the face of this bison cow as she grazed across the prairie. It will eventually fall off, and if it lands in a suitable location, it will germinate and produce a new licorice plant, far from the parent plant.




Chapter 6 Landscape Disturbance By Bison

In 2015, Johane and I had the opportunity to participate in the translocation of a herd of wood bison into central Alaska. After the release, the herd of more than one hundred head dispersed and here they forage across a vast landscape of wet sedge meadows. Today, they are providing disturbances similar to when the Steppe bison crossed from Siberia through Beringia and into North America 130,000 years ago.

Joseph Springer said there are seven ways that mammals affect prairie ecosystems: through pollination, changes to soil fertility, soil compaction, soil disturbance, seed dispersal, consumption of seeds, and the consumption of vegetation.



Chapter 7 Bison And Bugs

If you have had the chance to quietly sit and watch a herd of bison graze, you likely also have had the chance to feed a few of the millions of biting insects that plague the bison.

The grassland insect communities are incredibly diverse, and this diversity is partially responsible for the complexity (population dynamics, species composition, distribution, reproductive rates, survival, and so on) of the grassland bird community.




Chapter 8 Bison And Birds

The setting prairie sun showcases the ancient relationship between plains bison and brown-headed cowbirds. Everywhere that we have travelled on the trail of bison, we have witnessed this relationship between birds and bison.

With over eleven hundred avian species found in North America, it is not feasible to examine the relationships each of them may have had with bison.




Chapter 9 Bison and Small Mammals

A great gray owl killed and partially consumed a ruffed grouse, in the aspen parkland of central Alberta. This least weasel found the remains and dined for several days on the bounty of this chance find. Weasels are more typically predators of the mice and voles that are common throughout this part of the bison range. Weasels are often found in the burrow systems of pocket gophers, where they hunt pocket gophers, mice, and voles; and these, in turn, are abundant in landscapes grazed by bison. 

Mice, voles, and shrews require a wide range of habitat types for foraging, nesting, and general life maintenance. Bison, as a native grassland rotational grazer, create an intricate mosaic of small to large patches of mature grasses and forbs, interspersed with close-cropped grasslands. This creates an environment that ideally suits small mammals—one where seeds are produced in the thatch stands, nesting material is readily available, escape/security cover is adequate, and highly succulent forage is available nearby in the closely cropped areas. The diversity of habitat types on this micro-scale creates an environment that can support a wide range of small mammal species.


Chapter 10 Bison And Amphibians And Reptiles

A Canadian toad cautiously emerges from under a plantain leaf, into the dust of an adjacent bison wallow. These wallows are the prairie’s guestbook—a place where all visitors, including Johane and I, stop to leave our footprint signatures in the dust.

One group of species we had not anticipated, far from permanent water, were amphibians. Species such as the boreal and western chorus frogs, the northern cricket frog, as well as Great Plains, spade-foot, and Canadian toads all use these ephemeral wetlands during their life cycle.




Chapter 11 Bison And Ungulates

Elk and bison in the “cross timbers” region of the tallgrass prairie. The cross timbers is a fairly narrow strip of land extending from southeastern Kansas, through Oklahoma and into central Texas. This area represents the transition from grasslands to the eastern hardwood forests and is the eastern limit of many obligate grassland species.

Bison are sympatric with many other ungulates. This means that they will share space and time with other ungulate species. Yet within the ungulate guild, there is a strict interspecies hierarchy, with bison always dominant over the other ungulate species. As a result, they can out-compete the other species for forage. In this grassland ungulate hierarchy, bison are followed by herds of elk, then pronghorns and white-tailed and mule deer. Bison are the only native, non-selective herbivore to occupy the plains of North America, and their foraging behaviour influences that of all other native herbivores.



Chapter 12 Predators And Bison

A grizzly bear feeds on a bison carcass in Yellowstone National Park. We watched as he buried the carcass under grass and local debris. He left the site after a quick meal, and within a short while a sow grizzly with three young-of-the-year cubs arrived and worked busily at eating as much as they could before the bear returned.

Bison and their predators have coexisted for thousands of years. Wolves have been nipping at the heels of bison for a very long time—upwards of 400,000 years in Europe, and 100,000 years in North America.2 Across Europe, Asia, and North America, wolf predation has helped to drive bison evolution into modern plains, woods, or European bison that we see today. And to some extent, bison have helped to mould the wolf into the effective predator that it is.


Chapter 13 The Ecology Of Bison Carcasses And Scavengers

The grief was almost palpable to us as we watched other bison pay their respects to a fallen member of the herd. For as long as there have been bison, bulls like this one have died from injuries sustained during breeding-season battles.

As one of North America’s longest-living ungulates, often more than twenty-five years in the wild,1 bison contribute a huge amount to the trophic ecology of their ecosystems throughout their lives.




Chapter 14 Rewilding Returning Bison To Their Ancestral Lands

Johane and I watched as, after offloading the last shipment of wood bison, a C-130 Hercules departs from the airstrip at Shaguluk, Alaska. It required multiple flights with this aircraft to fly in the supplies required to support this translocation and several more to bring one hundred wood bison from their home at the Alaska Wildlife Conservation Center, south of Girdwood, Alaska.

Across Europe there is a large-scale movement to rewild nature.1 The organization Rewilding Europe defines “rewilding” as ensuring “natural processes and wild species to play a much more prominent role in the land- and seascapes, meaning that after initial support, nature is allowed to take more care of itself. Rewilding helps landscapes become wilder, whilst also providing opportunities for modern society to reconnect with such wilder places for the benefit of all life.


The Ecological Buffalo


By way of closing, I want to say why I believe this book
should be on everybody’s reading list. Though this book
may seem to be only about BISON, it has a much deeper
message and a much broader scope, and its message is critically
important for our times.


Bison Ecology - Wes Olson


Wes Olson was raised in the foothills of western Alberta, and there he developed a passion for wild places and wild species. Following a thirty-two-year career as a Canadian National Park warden, Wes has developed an international reputation for his knowledge about both plains and wood bison. He now lives on an eighty-acre patch of forest and beaver ponds beside Elk Island National Park in central Alberta and is the author of A Field Guide to Plains Bison and Portraits of the Bison: An Illustrated Guide to Bison Society.




Bison Ecology - Johane Janelle

Through life’s twists and turns, Johane Janelle has managed to work in a variety of nature-related fields. Her photography has been featured on many magazine covers, such as Horse-Sport, Horse-Canada, Horse & Country, and Western Horse Review, as well as in the books Portraits of the Bison: An Illustrated Guide to Bison Society and A Field Guide to Plains Bison. Johane resides on the doorstep of Elk Island National Park, in the heart of Canada’s national plains and wood bison recovery herds, where she is provided with unlimited inspiration for her art.





Copyright © 2022 Wes Olson Illustrations copyright © 2022 Wes Olson Photographs copyright © 2022 Johane Janelle & Wes Olson
All rights reserved. No part of this work covered by the copyrights hereon may be reproduced or used in any form or by any means—graphic, electronic, or mechanical—without the prior written permission of the publisher. Any request for photocopying, recording, taping or placement in information storage and retrieval systems of any sort shall be directed in writing to Access Copyright.


Image Credits:
All photographs by Johane Janelle, except those by Wes Olson on pages 54, 59, 65, 66, 75, 154, 158, 162, 201, 219, 241, and 242, by Helen Trefry on page 195, and by Nick Cairns on page 213. All maps, illustrations, and tables created by Wes Olson.
“Facing the Fear,” artist Neil Jones, oil on canvas. Image courtesy Neil Jones (