Grassland Arthropods of Canada's Endangered Ecosystem
Beneath the vast, sweeping skies of the Canadian prairies lies one of the planet's most endangered ecosystems—a world where an intricate web of life thrives in the grasses, yet remains largely unseen by human eyes.
While many Canadians might envision endless golden fields of grain when they think of the prairies, few have witnessed a native mixed-grass prairie ecosystem. Tragically, over 80% of Canada's Prairie grasslands have already been lost, making the remaining fragments critically important for biodiversity, carbon storage, and ecological resilience 6 .
of Canada's Prairie grasslands have been lost
These grasslands are not just beautiful landscapes—they are powerful carbon sinks that store massive amounts of carbon in their soil and roots, provide habitat for wildlife (particularly species at risk), retain water to withstand droughts, and are home to many of Canada's Indigenous nations 1 .
In this fragile world beneath our feet exists an entire universe of tiny engineers—the arthropods of the grasslands. Often overlooked in conservation efforts, these insects, spiders, and other invertebrates form the foundation of grassland health, yet their fate is inextricably tied to our own.
Arthropods—including insects, spiders, mites, and their relatives—represent the unseen majority of grassland biodiversity. They are the tiny engineers that perform essential services to keep the ecosystem functioning.
Grassland arthropods encompass an astonishing array of species adapted to life in prairie environments.
Through their feeding activities and movement through soil layers, arthropods enhance soil structure, aeration, and nutrient availability.
Arthropods serve as the critical link between primary producers (plants) and higher trophic levels.
Through herbivory, seed predation, and pollination, arthropods influence which plants thrive.
The loss of even a single arthropod species can have cascading effects throughout the entire ecosystem.
The Biological Survey of Canada has dedicated decades to documenting these creatures through its Arthropods of Canadian Grasslands project, which began in 1979 to address the significant knowledge gaps about these essential organisms 5 . Before this initiative, other than a few pest species, the arthropods of Canada's grasslands had been virtually ignored by science, despite their crucial role in maintaining ecological balance.
The relationship between grazing practices and arthropod communities represents one of the most fascinating and important areas of grassland ecology.
A revealing 2015 study published in PLoS ONE provides compelling evidence about how cattle grazing reverberates through the entire arthropod food web 2 .
Researchers established a sophisticated field experiment at the University of California Sierra Foothills Research and Extension Center to examine how arthropod communities respond to different grassland conditions 2 .
Plots with native perennial bunchgrasses versus non-native annual grasses
Six levels of grazing pressure, from ungrazed to heavily grazed
Multiple blocks and plots for each treatment combination
Using vacuum sampling methods to collect arthropods
The results revealed striking shifts in the arthropod community structure between grazed and ungrazed plots 2 :
| Arthropod Group | Effect of Grazing | Magnitude of Change |
|---|---|---|
| Herbivorous Arthropods | Significant increase in biovolume | 79% higher in grazed plots |
| Predatory Arthropods | Moderate decrease in biovolume | 13% lower in grazed plots |
| Overall Community Composition | Distinct shifts between grazed and ungrazed areas | Notable differences |
Perhaps surprisingly, the study found that arthropod richness and diversity did not vary consistently between native and non-native plant communities, suggesting that the changes in plant composition might be less important than the alterations in plant structure and quality that accompany grazing 2 .
Understanding the hidden world of grassland arthropods requires specialized methods and tools.
| Research Method | Primary Function | Applications in Grassland Research | Limitations |
|---|---|---|---|
| Vacuum Sampling | Collection of small, vegetation-inhabiting arthropods | Effective for sampling many groups of small arthropods; provides standardized samples | Less effective for large, mobile arthropods that can escape |
| Pitfall Trapping | Capture ground-dwelling arthropods | Studying beetle, spider, and other ground-active species | Bias toward active species; affected by weather |
| Sweep Netting | Collection of insects from vegetation | Quick assessment of plant-dwelling insects; useful for pollinators and herbivores | Less quantitative than other methods; vegetation structure affects results |
| Soil Core Sampling | Extraction of soil-dwelling organisms | Studying decomposition communities, soil health indicators | Labor-intensive processing; identification challenges |
| Genetic Analysis | Species identification and diversity assessment | Biodiversity studies through DNA barcoding; cryptic species identification | Requires specialized equipment and expertise; higher cost |
The Arthropods of Canadian Grasslands project has employed all these methods and more across its four-volume monograph series that represents the most comprehensive documentation of these organisms in Canada 5 .
Grasslands, particularly native grasslands, are considered "the single most endangered ecosystem in Canada" 1 . The numbers are alarming:
Multiple approaches are being employed to conserve and restore grassland ecosystems:
| Conservation Strategy | Implementation | Benefits for Arthropods | Challenges |
|---|---|---|---|
| Protected Areas | Establishing and managing parks and reserves | Habitat preservation; reduced pesticide use; maintenance of natural conditions | Limited area; potential isolation from other habitats |
| Sustainable Agriculture | Rotational grazing; reduced chemical inputs; maintained native vegetation | Diverse habitat structure; reduced direct mortality; food source maintenance | Economic pressures for intensification; knowledge barriers |
| Corridor Creation | Connecting habitat fragments with wildlife-friendly plantings | Increased genetic exchange; recolonization opportunities; climate change adaptation | Land acquisition and management; long-term maintenance |
| Native Plant Restoration | Revegetating degraded areas with native species | Restoration of host plants and specialized habitats; reestablishment of ecological relationships | Limited availability of native seed; establishment challenges |
The Nature Conservancy of Canada has launched an ambitious plan aiming to protect 500,000 hectares by 2030—an area six times the size of Calgary 6 .
175,000 hectares protected to date
The story of Canada's grassland arthropods is ultimately a story about ourselves—about our relationship with the natural world and our responsibility as its stewards.
These tiny engineers, working silently beneath the prairie skies, perform services that sustain not just the grasslands themselves, but the human communities that depend on them. From the carbon stored in grassland soils that mitigates climate change to the water purification that ensures clean water supplies, healthy grasslands provide irreplaceable benefits to all Canadians.
"When we spider webs unite, we can tie up a lion" — modified African proverb
Protecting these ecosystems requires a collective effort that spans from individual actions to national policies. Each of us can contribute—by supporting conservation organizations, learning about Indigenous-led initiatives in our communities, advocating for sustainable agricultural policies, or simply taking time to appreciate the complex beauty of a native prairie.
The future of Canada's grasslands hangs in the balance, and with it, the future of the countless tiny engineers that sustain them. Their survival is our own, their prosperity our legacy. In protecting them, we ultimately protect ourselves.