Blending Indigenous and western science: Quantifying cultural burning impacts in Karuk Aboriginal Territory

The combined effects of Indigenous fire stewardship and lightning ignitions shaped historical fire regimes, landscape patterns, and available resources in many ecosystems globally. The resulting fire regimes created complex fire-vegetation dynamics that were further influenced by biophysical setting, disturbance history, and climate. While there is increasing recognition of Indigenous fire stewardship among western scientists and managers, the extent and purpose of cultural burning is generally absent from the landscape-fire modeling literature and our understanding of ecosystem processes and development. In collaboration with the Karuk Tribe Department of Natural Resources, we developed a transdisciplinary Monte Carlo simulation model of cultural ignition location, frequency, and timing to simulate spatially explicit cultural ignitions across a 264,399-ha landscape within Karuk Aboriginal Territory in northern California. Estimates of cultural ignition parameters were developed with Tribal members and knowledge holders using existing interviews, historical maps, ethnographies, recent ecological studies, contemporary maps, and generational knowledge. Spatial and temporal attributes of cultural burning were explicitly tied to the ecology of specific cultural resources, fuel receptivity, seasonal movement patterns, and spiritual practices. Prior to colonization, cultural burning practices were extensive across the study landscape with an estimated 6972 annual ignitions, averaging approximately 6.5 ignitions per Indigenous fire steward per year. The ignition characteristics we document align closely with data on historical fire regimes and vegetation but differ substantially from the location and timing of contemporary ignitions. This work demonstrates the importance of cultural burning for developing and maintaining the ecosystems present at the time of colonization and underscores the need to work collaboratively with Indigenous communities to restore ecocultural processes in these systems.

Evaluating density-weighted connectivity of black bears (Ursus americanus) in Glacier National Park with spatial capture-recapture models

BACKGROUND

Improved understanding of wildlife population connectivity among protected area networks can support effective planning for the persistence of wildlife populations in the face of land use and climate change. Common approaches to estimating connectivity often rely on small samples of individuals without considering the spatial structure of populations, leading to limited understanding of how individual movement links to demography and population connectivity. Recently developed spatial capture-recapture (SCR) models provide a framework to formally connect inference about individual movement, connectivity, and population density, but few studies have applied this approach to empirical data to support connectivity planning.

METHODS

We used mark-recapture data collected from 924 genetic detections of 598 American black bears (Ursus americanus) in 2004 with SCR ecological distance models to simultaneously estimate density, landscape resistance to movement, and population connectivity in Glacier National Park northwest Montana, USA. We estimated density and movement parameters separately for males and females and used model estimates to calculate predicted density-weighted connectivity surfaces.

RESULTS

Model results indicated that landscape structure influences black bear density and space use in Glacier. The mean density estimate was 16.08 bears/100 km2 (95% CI 12.52-20.6) for females and 9.27 bears/100 km2 (95% CI 7.70-11.14) for males. Density increased with forest cover for both sexes. For male black bears, density decreased at higher grizzly bear (Ursus arctos) densities. Drainages, valley bottoms, and riparian vegetation decreased estimates of landscape resistance to movement for male and female bears. For males, forest cover also decreased estimated resistance to movement, but a transportation corridor bisecting the study area strongly increased resistance to movement presenting a barrier to connectivity.

CONCLUSIONS

Density-weighed connectivity surfaces highlighted areas important for population connectivity that were distinct from areas with high potential connectivity. For black bears in Glacier and surrounding landscapes, consideration of both vegetation and valley topography could inform the placement of underpasses along the transportation corridor in areas characterized by both high population density and potential connectivity. Our study demonstrates that the SCR ecological distance model can provide biologically realistic, spatially explicit predictions to support movement connectivity planning across large landscapes.

Arthropods and Fire Within the Biologically Diverse Longleaf Pine Ecosystem

The longleaf pine Pinus palustris Miller (Pinales: Pinaceae) ecosystem once covered as many as 37 million hectares across the southeastern United States. Through fire suppression, development, and conversion to other plantation pines, this coverage has dwindled to fewer than 2 million hectares. A recent focus on the restoration of this ecosystem has revealed its complex and biologically diverse nature. Arthropods of the longleaf pine ecosystem are incredibly numerous and diverse-functionally and taxonomically. To provide clarity on what is known about the species and their functional roles in longleaf pine forests, we thoroughly searched the literature and found nearly 500 references. In the end, we tabulated 51 orders 477 families, 1,949 genera, and 3,032 arthropod species as having been stated in the scientific literature to occur in longleaf pine ecosystems. The body of research we drew from is rich and varied but far from comprehensive. Most work deals with land management objective associated taxa such as pests of pine, pests of-and food for-wildlife (red-cockaded woodpecker, northern bobwhite quail, gopher tortoise, pocket gopher, etc.), and pollinators of the diverse plant understory associated with longleaf pine. We explored the complex role frequent fire (critical in longleaf pine management) plays in determining the arthropod community in longleaf pine, including its importance to rare and threatened species. We examined known patterns of abundance and occurrence of key functional groups of longleaf pine-associated arthropods. Finally, we identified some critical gaps in knowledge and provide suggestions for future research into this incredibly diverse ecosystem.

Effects of traditional harvest and burning on common camas (Camassia quamash) abundance in Northern Idaho: The potential for traditional resource management in a protected area wetland

The bulbs of common camas (Camassia quamash) were a staple food of Indigenous Peoples of western North America for millennia. Camas harvesting site productivity was encouraged through intense management. Common camas is considered a facultative wetland species, and populations have declined due to contemporary wetland drainage and land conversion. Conservation of existing habitat, as well as restoration of degraded systems, is necessary. Traditional ecological knowledge (TEK) and resource management (TRM) are often promoted as viable modes of contemporary resource management but are rarely tested or implemented. We designed a controlled experiment, informed by a born-in-the-tradition specialist, to evaluate the response of common camas populations to traditional bulb harvest, burning, and a combination of harvest and burning. We recorded camas plant counts of three life stage classes of camas plants (single-leaf seedling, multiple-leaf adult, and flowering adult) over the course of 6 years in arrays of plots and subjected to treatments or left undisturbed as control. Harvesting removed plants (>800 bulbs) and reduced aboveground counts of camas densities ( X ¯  ~ 50% of control, p < .05). Burning contributed to a reduction in single-leaf plants but had an overall positive effect ( X ¯  ~ 150% of control, p < .05) on adult camas and flowering plant abundance, and ameliorated the digging impacts. Treatment impacts tapered over the course of the study, and results indicate that a sustainable harvesting return interval of approximately 5 years may be possible when combined with fire to reduce litter and competition from pasture grasses and to accelerate the recovery of camas. Our findings support the hypotheses proposed by traditional knowledge specialists and ethnobotanists that digging and burning reduce intra- and interspecific competition and stimulate the growth of unharvested adult plants. More generally, our study supports the integration of traditional ecological knowledge into the evidence base available for protected area wetland prairie management.

Challenges during the execution, results, and monitoring phases of ecological restoration: Learning from a country-wide assessment

Outcomes from restoration projects are often difficult for policymakers and stakeholders to assess, but this information is fundamental for scaling up ecological restoration actions. We evaluated technical aspects of the interventions, results (ecological and socio-economic) and monitoring practices in 75 restoration projects in Mexico using a digital survey composed of 137 questions. We found that restoration projects in terrestrial ecosystems generally relied on actions included in minimal (97%) and maximal (86%) intervention, while in wetlands, the preferred restoration strategies were intermediate (75%) and minimal intervention (63%). Only a third of the projects (38%) relied on collective learning as a source of knowledge to generate techniques (traditional management). In most of the projects (73%), multiple criteria (>2) were considered when selecting plant species for plantings; the most frequently used criterion was that plant species were found within the restoration area, native or naturalized (i.e., a circa situm criterion; 88%). In 48% of the projects, the biological material required for restoration (e.g., seeds and seedlings) were gathered or propagated by project implementers rather than purchased commercially. Only a few projects (between 33 and 34%) reached a high level of biodiversity recovery (>75%). Most of the projects (between 69 to71%) recovered less than 50% of the ecological services. Most of the projects (82%) led to improved individual relationships. The analysis revealed a need to implement strategies that are cost-effective, the application of traditional ecological knowledge and the inclusion of indigenous people and local communities in restoration programs at all stages—from planning to implementation, through monitoring. We also identified the need to expand research to develop effective tools to assess ecosystems’ regeneration potential and develop theoretical frameworks to move beyond short-term markers to set and achieve medium- and long-term goals. Cautious and comprehensive planning of national strategies must consider the abovementioned identified gaps.

Defining historical baselines for conservation: ecological changes since European settlement on Vancouver Island, Canada

Conservation and restoration goals are often defined by historical baseline conditions that occurred prior to a particular period of human disturbance, such as European settlement in North America. Nevertheless, if ecosystems were heavily influenced by native peoples prior to European settlement, conservation efforts may require active management rather than simple removal of or reductions in recent forms of disturbance. We used pre-European settlement land survey records (1859-1874) and contemporary vegetation surveys to assess changes over the past 150 years in tree species and habitat composition, forest density, and tree size structure on southern Vancouver Island and Saltspring Island, British Columbia, Canada. Several lines of evidence support the hypothesis that frequent historical burning by native peoples, and subsequent fire suppression, have played dominant roles in shaping this landscape. First, the relative frequency of fire-sensitive species (e.g., cedar [Thuja plicata]) has increased, whereas fire-tolerant species (e.g., Douglas-fir [Pseudotsuga menziesii]) have decreased. Tree density has increased 2-fold, and the proportion of the landscape in forest has greatly increased at the expense of open habitats (plains, savannas), which today contain most of the region's threatened species. Finally, the frequency distribution of tree size has shifted from unimodal to monotonically decreasing, which suggests removal of an important barrier to tree recruitment. In addition, although most of the open habitats are associated with Garry oak (Quercus garryana) at present, most of the open habitats prior to European settlement were associated with Douglas-fir, which suggests that the current focus on Garry oak as a flagship for the many rare species in savannas may be misguided. Overall, our results indicate that the maintenance and restoration of open habitats will require active management and that historical records can provide critical guidance to such efforts.

ARCHAEOLOGY, ECOLOGICAL HISTORY, AND CONSERVATION

Ecologists have increasingly turned to history, including human history, to explain and manage modern ecosystems and landscapes. The imprint of past land use can persist even in seemingly pristine areas. Archaeology provides a long-term perspective on human actions and their environmental consequences that can contribute to conservation and restoration efforts. Case studies illustrate examples of the human history of seemingly pristine landscapes, forest loss and recovery, and the creation or maintenance of places that today are valued habitats. Finally, as archaeologists become more involved in research directed at contemporary environmental issues, they need to consider the potential uses and abuses of their findings in management and policy debates.