Robin Wall Kimmerer

Weaving Traditional Ecological Knowledge into Biological Education: A Call to Action

A s scientists and educators, we train our students to thoroughly examine all the available evidence and to consider alternative explanations for biological phenomena. In peer review, we critically assess whether the author has carefully cited the appropriate primary sources. And yet, in our biology curricula, we are perhaps unknowingly ignoring an entire body of knowledge that has potential significance to contemporary science and policy: traditional ecological knowledge (TEK). Indigenous peoples are the stewards of fully 4 percent of the land area of the United States and represent some 700 distinct communities possessing detailed knowledge of the biota of their homelands. Native American land holdings in North America collectively contain more wildlands than all of the national parks and nature conservancy areas in North Amer-ica (Nabhan 2000). Globally, indigenous peoples inhabit areas with some of the highest remaining biodiversity on the planet (Durning 1992) and are actively engaged as partners in biodiversity conservation (Weber et al. 2000). Issues of sustainable development, resource management, and ecological restoration all include Native American stakeholders. Federal agencies are required to consult with tribes on a government to government basis on a host of scientific and natural resource policies. Thus, college biology graduates have a high probability of encountering issues involving indigenous cultures and TEK. However, the majority of scientific professionals and educators have little understanding of the value of TEK or its cultural context. Traditional ecological knowledge is increasingly being sought by academics, agency scientists, and policymakers as a potential source of ideas for emerging models of ecosystem management, conservation biology, and ecological restoration. It has been recognized as complementary and equivalent to on Biodiversity calls for recognition, protection, and utilization of TEK. Researchers in pharmaceutical laboratories and in agricultural experiment stations worldwide are beginning to recognize the knowledge of indigenous peoples in scientific research. New directions in applied biology that have direct parallels and precedents in traditional knowledge include ecosystem management, medicine, pharmacology, agroecology, wildlife, fisheries, and animal behavior. Biological research is moving to explore these approaches, yet acknowledgment or understanding of traditional ecological knowledge is rare in the scientific community. Most college ecology courses begin a history of the discipline with 19th-century Europe, neglecting the highly sophisticated precedents in indigenous knowledge systems. My goal in this article is to present the case that exposure to TEK has a legitimate role in the education of the next generation of biologists, environmental scientists, and …

Reproductive Ecology of Tetraphis pellucida II. Differential Success of Sexual and Asexual Propagules

Sexual and asexual propagules of Tetraphis pellucida differ in dispersal pattern and establishment success. In field and laboratory trials, the spore dispersal pattern was leptokurtic, but a significantfraction of the spores was trapped asfar as 2 mfrom the colony. Gemmae were dispersed within 10 cm of the colony. The two forms of gemmiferous shoots, cupped and stalked, differed in microtopographic distribution but did not differ significantly in dispersal potential. Stalk-gemmae were positively associated with steeply sloped microsites. Gemmae were far more successful than spores in establishment of new shoots on bare substrate. Neither gemmae nor spores were capable of colonizing in the presence of established competitors. Production of gemmae facilitates local colonization of decaying stumps, whereas spore production ensures long-distance dispersal to newly

Ecological Consequences of Sexual versus Asexual Reproduction in Dicranum flagellare and Tetraphis pellucida

To test hypotheses of the relative advantages of sexual and asexual reproduction, the reproductive ecology ofDicranum flagellare is compared to that ofTetraphis pellucida. Both species share a habitat preference for decaying logs of the forest floor, but they differ in reproductive mode. In D. flagellare asexual reproduction predominates, whereas T. pellucida produces both sexual and asexual propagules. The ecological consequences of reliance on asexual reproduction are explored: dispersal, colonization, and spatial distribution. The asexual brood branches of D. flagellare suc- cessfully colonize gaps produced by disturbance, but only when D. flagellare is present in the nearby vegetation. The local distribution ofD. flagellare is limited to spatially aggregated substrates, whereas T. pellucida is widely dispersed. Dicranum flagellare invests significantly more biomass in asexual reproduction, but the overall reproductive effort of T. pellucida exceeds that of D. flagellare. Brood branches of D. flagellare germinate significantly more rapidly than Tetraphis gemmae. Dicranum flagellare persists longer than T. pellucida in log communities, perhaps as a result of accumulation of perennial shoot increments. The distribution of bryophytes through a wide range of transient microhabitats reflects the evolu- tion of diverse reproductive strategies. Bryophyte life histories range from fugitive species that rely on sexually produced spores to species whose repro- ductive effort is entirely asexual. The adaptive sig- nificance (if any) of these reproductive patterns is not well understood (Mishler 1988). It has been suggested that bryophyte reproduction involves a balance between the long-term advantages of sexual reproduction and the more immediate benefits of asexual propagation (Cummins & Wyatt 198 1). The nature of this balance may shift with changing en- vironmental conditions--in particular, the distur- bance regime. Recent studies demonstrate that ad- aptation to disturbance frequency may be a strong selective pressure on the reproductive ecology of the forest floor bryophyte Tetraphis pellucida (Kim- merer 1991a,b, 1993).

Disturbance and Dominance in Tetraphis pellucida: A Model of Disturbance Frequency and Reproductive Mode

The role of disturbance in maintenance of ecological dominance by Tetraphis pellucida Hedw. is examined in field studies and an empirical model. Patterns of compositional change in T. pellucida-dominated communities are summarized in a matrix of transition probabilities. Open substrate patches are most frequently replaced by asexual colonies which gradually change to the sexual state. Most sexual patches persist, or are overcome by competitors, but a significant fraction of the patches experience disturbance. A Markov model is used to predict the effects of varying disturbance frequency on the relative abundance of sexual, asexual, and senescent colonies, as well as on the success ofcompetitors. Experimental reduction in disturbancefrequency causes an increase in competitors and the local extinction of T. pellucida. Tetraphis pellucida maintains ecological dominance by exploiting frequently disturbed microsites. Its dual reproductive modes allow it to perpetuate itself by gemmae in frequent, local disturbances, and to escape to distant disturbances via spore production. Microhabitat preference ofT. pellucida for decayed stumps over adjacent logs may be correlated with differing disturbance frequencies. These findings suggest that disturbance may be an important selective pressure in maintaining dual reproductive modes in this species.

Effect of gap size and regeneration niche on species coexistence in bryophyte communities

Relative abundance of the two species varies with availability of the appropriate regeneration niche, which is a function of the local disturbance regime. Rodent activity may both produce the gaps favored by D. flagellare and facilitate its dispersal to them. Dominance of T. pellucida is associated with larger gaps produced by decay. The interaction of the regeneration niche and the disturbance regime are found to be primary determinants of community structure on this unstable substrate.

Bryophyte Species Richness on Insular Boulder Habitats: The Effect of Area, Isolation, and Microsite Diversity

Abstract The bryophyte communities on glacial erratic boulders in the Adirondack Mountains of New York are used as an experimental system to test the predictions of island biogeographic theory. Moss species composition, abundance, richness, and diversity were determined for 39 boulders. Bryophyte species richness on these insular habitats ranges from 3 to 14. Competitive dominance of the component moss species was determined. Boulders were characterized as to size, degree of isolation, and microhabitat heterogeneity. Patterns of disturbance and gap formation in the moss cover, and patterns of recolonization were quantified. The distribution of bryophyte species among individual boulders does not conform to the predictions of island biogeographic theory. Neither the size of the boulder nor its degree of isolation are significantly related to species richness. Richness was also found to be independent of the abundance of the competitive dominants. Overall measures of microhabitat heterogeneity were not correlated with species richness, although a weak relationship with microtopographic diversity was detected. We suggest that the high frequency of gap formation on these boulders maintains the community in a non-equilibrium state. The observed patterns of species richness may be the result of population level processes that govern dispersal and establishment among boulders and among gaps on the boulder surface.

Reproductive ecology of Tetraphis pellucida. I : Population density and reproductive mode

The reproductive mode and population structure of Tetraphis pellucida vary with shoot density. Low-density colonies reproduce asexually by gemmae and have a female-biased sex ratio. Increased density is correlated with increased sexual reproduction (sporophyte production). High levels of sporophyte production are accompanied by an increase in the proportion of males and by the onset of senescence. Plasticity of reproductive allocation can increase the fitness of T. pellucida in an unstable environment. The view has been advanced that reproduction in bryophytes represents a balance between the shortterm advantages of clonal propagation and longterm advantages of sexual reproduction (Cummins & Wyatt 1981; McQueen 1985). Validation of this idea has been limited by a scarcity of quantitative data (Mishler 1988). Relative allocation to sexual and asexual reproduction has never been measured in bryophyte populations (During & van Tooren 1987). Understanding the ecological correlates of reproductive mode is an essential prerequisite to assessing the relative importance of sexual and asexual reproduction. Tetraphis pellucida Hedw. provides an excellent model system in which to explore these questions. It is a common species of boreal and northern deciduous forests and becomes ecologically dominant on its preferred substrate of decaying coniferous wood (Forman 1964). This dominance may be aided by a life history strategy which includes two specialized modes of reproduction: spores and gemmae. Production of sexual and asexual propagules occurs on discrete shoots, facilitating estimates of reproductive allocation. Tetraphis pellucida is cladautoicous. Forman (1964) exhaustively described the distributional patterns of T. pellucida from the broad continental scale to its occurrence on particular microsites. Absent from this intensive analysis, however, is any consideration of the distribution of reproductive mode. Asexual and sexual reproduction are not mutually exclusive in Tetraphis but are discrete in distribution. A single stump may be dominated by purely gemmiferous colonies, while an adjacent site exhibits only sporophyte production. Within a common substrate, sexual and asexual colonies frequently coexist but do not often intermingle. The objective of this study was to examine the ecological factors governing the reproductive mode of T. pellucida. MATERIALS AND METHODS Study site.--The nearly 300 populations examined in this study are located at the SUNY Cranberry Lake Biological Station, Cranberry Lake, New York. Its location in the boreal-deciduous forest transition zone provides a range of forest types in which T. pellucida occurs. Populations were sampled from the following habitats: hardwood forests of upland and lowland sites, spruce flats, moist hemlock stands, dry pine stands, spruce-fir forests, mixed hardwood-conifer stands, and exposed lake-edge sites. Environmental correlates of reproductive allocation.The objective of these studies was to determine if reproductive allocation was significantly correlated with patterns of environmental variation. Three hundred colonies of T. pellucida were identified in sites encompassing the broadest possible range of habitat characteristics. A colony 0007-2745/91/255-260

The Role of Slugs in Dispersal of the Asexual Propagules of Dicranum flagellare

0.75/0 This content downloaded from 157.55.39.177 on Tue, 15 Nov 2016 03:55:36 UTC All use subject to http://about.jstor.org/terms 256 THE BRYOLOGIST [VOL. 94 was defined to be a distinct patch, separated from others by a minimum distance of 5 cm. The colonies selected for study differed in size, substrate, forest cover type, and topography. The following environmental variables were measured for each colony (n = 300) sampled: light (MEm-2 sec.-2), relative humidity, pH, substrate moisture content, elevation, microtopographic class, and cover by vascular and bryophyte competitors. Relative humidity and light were measured twice in June 1987. Light was expressed as average percent of full sun. Estimates of substrate pH were obtained by pressing high resolution pH paper to the moist substrates. Moisture content of the substrate was determined gravimetrically. The location of each colony was described as to elevation (height above the forest floor) and microtopographic class (promontory, depression, or plane surface). Percent cover of competitors was estimated from detailed grid maps, where species presence was tallied in each of 400 1-cm2 grid units centered on the sampled colony. The relative proportions of shoots bearing gemmae or sporophytes were determined for a 200-shoot representative subsample of each colony. Correlation between environmental variables and reproductive mode was tested by linear regression. Patterns of association between substrate, cover type, microtopographic class, and reproductive mode were determined by x2 analysis. Sampling was conducted June-July 1987. Reciprocal transplants.--Reciprocal transplant experiments were established on a single large decayed log which supported sexual and gemmiferous colonies of T. pellucida in different regions. Five blocks of Tetraphis (9 cm2), with a minimum of attached substrate, were removed from the sporophyte-bearing colonies and transplanted to gaps prepared in the gemmiferous colonies. A 9-cm2 area of the gemmiferous colony and substrate was cut away to form the gap. The transplant was fitted into the gap and tamped into place, level with the surrounding colony. One additional sporophytic block was transplanted within the sexual colony as a control. Five gemmiferous blocks were reciprocally transplanted into the midst of the sexual colonies and a control established in the gemmiferous region. Transplants were left in place for 15 months. The proportion of sporophytic and gemmiferous shoots in each block was determined before and after transplanting. Population structure. -Approximately 25 discrete clumps of T. pellucida representing a range of shoot densities were collected from a uniform substrate-decayed coniferous wood. Samples (1 cm2) were excised from the clump for analysis of population structure. Population structure is defined as the relative proportions of different shoot types. Every shoot in each sample was classified. Shoots were categorized as vegetative or as senescent (> 50% of leaves brown), or as bearing archegonia, antheridia, gemmae, new sporophytes (capsule and seta green), old sporophytes (capsule and seta brown and dry), or aborted sporophytes (capsule failed to develop). The relative proportions of each shoot type were determined. The relationship between population density and population structure was analyzed by linear or exponential regression. Percentage data were arcsine-square root-transformed. The minimum distance between sporophytes and male shoots (n = 5) was measured for each clump. An operational sex ratio was based on the relative proportions of male and female gametophores, to reflect current allocation patterns. In 30 samples, shoots bearing old sporophytes were carefully dissected from the colony and examined for the presence of lateral innovations. The innovations were classified as

The Effect of Polytrichum piliferum on Seed Germination and Establishment on Iron Mine Tailings in New York

Dicranum flagellare Hedw. depends primarily on the dispersal ofasexual brood branch- es to colonize disturbance gaps on decaying logs. Forest slugs appear to be a significant dispersal vector. Propagules became entrapped in the slug secretions and were deposited in the slime trail. Field and laboratory trials demonstrated that slugs can detach and transport brood bodies at least 23 cm from the colony, although the mean dispersal distance was only 3.7 cm. The presence of slug secretions did not affect propagule germination rate, but did significantly increase adherence to the substrate.

Searching for synergy: integrating traditional and scientific ecological knowledge in environmental science education

Abstract Seedling establishment on iron mine tailings in New York States Adirondack Park was studied to determine if cover by the bryophyte Polytrichum piliferum Hedw. facilitated or inhibited seed germination and seedling survival, relative to other substrates present on the site. The occurrence of vascular vegetation on the four most commonly occurring substrates (bare tailings, cryptogamic crust, grass litter, and Polytrichum piliferum) was compared. An association survey detected preferential association between vascular vegetation and cover of Polytrichum piliferum, particularly for winter annual and biennial species. Seeds of Panicum virgatum L. and Melilotus officinalis (L.) Pallas were experimentally sown onto the four natural substrates, as well as on artificial substrates designed to mimic bryophyte turf. Germination on Polytrichum turf exceeded that of other substrates. However, seedling survivorship was low on all substrates, with no seedling surviving past 13 wk. Shade treatment on natural substrates significantly increased germination and somewhat extended survival. The results suggest that Polytrichum cover acts as a safe site for species that germinate and establish in cooler weather. However, even experimental shading of moss turf does not ameliorate summer heat stress sufficiently to permit establishment of seeds that germinate in early summer.