Indigenous Studies Speaks to Environmental Management

This article describes the increasing connections between the fields of Indigenous studies and environmental management and examines some of the ways that an Indigenous studies perspective can guide thinking about environmental management. Indigenous groups have been involved in the management of environmental and natural resources on their lands since time immemorial. Indigenous groups have also become increasingly involved in Western practices of environmental management with the advent of co-management institutions, subsistence boards, traditional ecological knowledge forums, and environmental issues affecting Indigenous resources. Thus, it is an important time for scholarship that explores how Indigenous groups are both shaping and being affected by processes of environmental management. This article summarizes key findings and themes from eight papers situated at the intersection of these two fields of study and identify means by which environmental managers can better accommodate Indigenous rights and perspectives. It is the authors’ hope that increased dialog between Indigenous studies and environmental management can contribute to the building of sustainable and socially just environmental management practices.     

Dioxins and polychlorinated biphenyls (PCDD/Fs and PCBs) in food from farms close to foot and mouth disease animal pyres

To control the outbreak of foot and mouth disease, which occurred in the UK in early 2001, a large number of farm animals were slaughtered. Where it was not possible to render or landfill the carcasses, they were destroyed by burning on open pyres, with wood, coal and other materials. Uncontrolled combustion such as this is known to produce small quantities of dioxins and an investigation was made into whether, as a result of the burning, there was an elevation in the concentrations of these compounds in food produced in the areas close to the pyres. With few exceptions, concentrations of PCDD/Fs and PCBs were within the expected ranges as predicted by reference data. No accumulation over time was evident from a repeat milk sampling exercise. Where elevated concentrations of PCDD/Fs and PCBs were found in chickens and eggs, they were in samples not destined for the food chain. Elevated levels in some samples of milk from Dumfries and Galloway were not found in earlier or later samples and may have been found as a result of a temporary feeding regime. Elevated concentrations in lamb from Carmarthenshire were from very young animals which would not have entered the food chain. There was no evidence of any significant increase in dietary exposure to PCDD/Fs and PCBs as a result of the FMD pyres.     

A gradient of mercury concentrations in Scottish single malt whiskies

Mercury (Hg) concentrations were measured in 26 Scottish single malt whiskies, and all found to be very low (<10 ng L⁻¹), posing no threat to human health through reasonable levels of consumption. However, a significant south-to-north declining gradient in Hg concentrations was observed reflecting that reported for atmospheric deposition. We speculate that this gradient could be due to a combination of contemporary deposition and the legacy of industrial mercury emissions and deposition over the last 200 years affecting concentrations in local waters used in whisky production. As UK atmospheric emissions of mercury have declined by 90 % since the 1970s, we suggest that whisky being produced today should have even lower Hg concentrations when consumed in 10- to 15-years time. This reduction may be compromised by the remobilisation of contaminants stored in catchment soils being transferred to source waters, but is very unlikely to raise the negligible health risk due to Hg from Scottish single malt whisky consumption.

     

Humpback whale song: who sings?

While on their winter breeding grounds, male humpback whales (Megaptera novaeangliae) produce long sequences of structured vocalizations called song, whose function within the mating system is still unresolved. Here we ask which males sing. Is it only those sexually mature, as typifies songbirds and some lekking ungulates in which vocalizations during the rut are restricted to mature males? Or do immature males join in the chorus? Using an underwater videogrammetric technique, we measured the body lengths of 87 humpback singers in the Hawaiian winter grounds. Applying length and sexual maturity relationships for North Pacific humpbacks as determined by biologists aboard twentieth century Japanese whaling vessels, we found that singer lengths ranged from 10.7 to 13.6 m, with 15 % of lengths indicative of probable sexual immaturity (length?<?11.3 m, p [maturity]?<?0.5). We interpret this broad participation of males as a lekking aggregation and the asynchronous singing chorus as an instance of by-product mutualism. The participation of many singers yields a heightened signal level that may attract more females to the singing area. Sexually mature males can benefit through access to more females. Immature males may gain deferred benefits through increased opportunities to learn and practice the social, behavioral, and acoustical skills and conventions of the winter grounds that they can apply usefully in later years.     

Plant growth rates and seed size: a re-evaluation

Small-seeded plant species are often reported to have high relative growth rate or RGR. However, because RGR declines as plants grow larger, small-seeded species could achieve higher RGR simply by virtue of their small size. In contrast, size-standardized growth rate or SGR factors out these size effects. Differences in SGR can thus only be due to differences in morphology, allocation, or physiology. We used nonlinear regression to calculate SGR for comparison with RGR for 10 groups of species spanning a wide range of life forms. We found that RGR was negatively correlated with seed mass in nearly all groups, but the relationship between SGR and seed mass was highly variable. We conclude that small-seeded species only sometimes possess additional adaptations for rapid growth over and above their general size advantage.     

Seed availability and insect herbivory limit recruitment and adult density of native tall thistle

Understanding spatial and temporal variation in factors influencing plant regeneration is critical to predicting plant population growth. We experimentally evaluated seed limitation, insect herbivory, and their interaction in the regeneration and density of tall thistle (Cirsium altissimum) across a topographic ecosystem productivity gradient in tallgrass prairie over two years. On ridges and in valleys, we used a factorial experiment manipulating seed availability and insect herbivory to quantify effects of: seed input on seedling density, insect herbivory on juvenile density, and cumulative impacts of both seed input and herbivory on reproductive adult density. Seed addition increased seedling densities at three of five sites in 2006 and all five sites in 2007. Insect herbivory reduced seedling survival across all sites in both years, as well as rosette survival from the previous year's seedlings. In both years, insecticide treatment of seed addition plots led to greater adult tall thistle densities in the following year, reflecting the increase in juvenile thistle densities in the experimental year. Seedling survival was not density dependent. Our analytical projection model predicts a significant long-term increase in adult densities from seed input, with a greater increase under experimentally reduced insect herbivory. While plant community biomass and water stress varied significantly between ridges and valleys, the effects of seed addition and insect herbivory did not vary with gradient position. These results support conceptual models that predict seedling and adult densities of short-lived monocarpic perennial plants should be seed limited. Further, the experiment demonstrates that even at high juvenile plant densities, at which density dependence potentially could have overridden herbivore effects on plant survival, insect herbivory strongly affected juvenile thistle performance and adult densities of this native prairie species.     

Spatial distribution of defense chemicals and markers and the maintenance of chemical variation

Exploring the spatial distribution of variation in plant secondary metabolites is critical for understanding the evolutionary ecology of biochemical diversity in wild organisms. In the present study, concentrations of foliar sideroxylonal, an important and highly heritable defense chemical of Eucalyptus melliodora, displayed strong, fine-scale spatial autocorrelation. The spatial patterns observed could promote associational effects on herbivore foraging decisions, which may influence the selection pressures exerted on sideroxylonal content. Multiple chemical traits have roles in certain eucalypt-herbivore interactions, and the spatial characteristics of the herbivore foraging environment are therefore determined by these different factors. We used a model of E. melliodora intake by common brushtail possums (Trichosurus vulpecula), based on the combined effects of two chemical traits, to explore this idea and found that the spatial patterns were different to those of sideroxylonal alone. Spatial genetic autocorrelation, examined using microsatellites, was strong and occurred at a fine scale, implying that restricted gene flow might allow genetic patches to respond to selection relatively independently. Local two-dimensional genetic autocorrelation, explored using a new heuristic method, was highly congruent with the pattern of local phenotypic variation observed for sideroxylonal, suggesting that the genetic variance underlying the sideroxylonal variation is similarly structured. Our results suggest that the spatial distribution of genetic and phenotypic variation could influence both the selective pressure imposed by herbivores on eucalypt defenses and the potential of populations to respond to natural selection. Spatial context should be considered in future studies of plant-herbivore interactions.     

Trace element pollution records in some UK lake sediments, their history, influence factors and regional differences

Sediment cores were taken from six sites across the UK. Apart from Banbury Reservoir in London, all the other sites are relatively remote lakes. Trace elements Pb, Zn, Cu, Cd, Cr, Ni, Sn, As and V, major elements such as Fe, Mn, Ti and Al were analysed, and organic content measured as loss-on-ignition was determined in all of these cores. The result shows that these relatively remote sites have experienced enhanced atmospheric deposition of anthropogenically derived trace elements for over 100 years, and the contamination might start before industrialisation. Trace metal contamination remains the highest level at Banbury Reservoir showing "pollution source" influence. Despite the considerable reduction in atmospheric deposition in recent years, although some of the element concentrations in the surface sediments have declined, they are still much higher than their natural background values. In these sites, trace element pollution records have been influenced by many different factors. Redox condition could affect As distribution in the sediments. Sediment matrix could also affect trace element pollution signal. Apart from direct atmospheric deposition, the distributions of trace elements in the sediments have been affected by forestry activities and catchment erosion, and more contaminated soil in-wash could increase sediment pollution whilst less contaminated soil could dilute sediment pollution. In some sites, data suggest that catchment in-wash is an important source of elements for the lakes.     

Land Use and Climate Variability Amplify Carbon,Nutrient, and Contaminant Pulses: A Review with Management Implications

Nonpoint source pollution from agriculture and urbanization is increasing globally at the same time climate extremes have increased in frequency and intensity. We review >200 studies of hydrologic and gaseous fluxes and show how the interaction between land use and climate variability alters magnitude and frequency of carbon, nutrient, and greenhouse gas pulses in watersheds. Agricultural and urban watersheds respond similarly to climate variability due to headwater alteration and loss of ecosystem services to buffer runoff and temperature changes. Organic carbon concentrations/exports increase and organic carbon quality changes with runoff. Nitrogen and phosphorus exports increase during floods (sometimes by an order of magnitude) and decrease during droughts. Relationships between annual runoff and nitrogen and phosphorus exports differ across land use. CH₄ and N₂O pulses in riparian zones/floodplains predominantly increase with: flooding, warming, low oxygen, nutrient enrichment, and organic carbon. CH₄, N₂O, and CO₂ pulses in streams/rivers increase due to similar factors but effects of floods are less known compared to base flow/droughts. Emerging questions include: (1) What factors influence lag times of contaminant pulses in response to extreme events? (2) What drives resistance/resilience to hydrologic and gaseous pulses? We conclude with eight recommendations for managing watershed pulses in response to interactive effects of land use and climate change.