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North American forests provide multiple ecosystem services, such as carbon storage, biodiversity, and recreation. These services are often coordinated through multifunctional management, whereby various users and owners contribute to collective agendas. Forests in exurban “transition” zones are crucial components in the sustainability of broader metropolitan landscapes, but represent a particularly understudied confluence of ecosystem services and multifunctional management. In this paper, we develop a place-based approach to assess ecosystem services in transitional forests (those between rural and urban). We demonstrate how trajectories of forest composition are linked with shifting ecosystem services that both shape and are shaped by management activities. Sited in Stinchfield Woods, a forest in southeast Michigan, this study draws on a household survey, interviews, ecological data, and archival information. Given variations in priorities over time and among different users, we suggest that coordinated, adaptive management may improve provisioning of ecosystem services in ways that benefit multiple users. 相似文献
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Kayla Deasley Jennifer B. Korosi Joshua R. Thienpont Steven V. Kokelj Michael F. J. Pisaric John P. Smol 《Journal of Paleolimnology》2012,48(2):287-296
An increase in the frequency and intensity of marine storm surges is a predicted consequence of climate warming, and therefore it is important to better understand the biological responses to such events in coastal regions. In late September 1999, a major storm surge resulted in a saltwater intrusion event over a large area of the Mackenzie Delta (NT, Canada) front, causing rapid salinization of lakes on the alluvial plain. Due to a lack of long-term ecological monitoring data in the region, the impacts that the saltwater intrusion event had on the biota of affected lakes were unknown. We used high-resolution paleolimnological approaches to reconstruct past assemblage changes in Cladocera from impacted Lake DZO-29 (unofficial name) in order to determine how different cladoceran species responded to a major increase in lake salinity following the 1999 storm surge. Camptocercus were extirpated from the lake following the saltwater intrusion and have not recovered. We also observed an initial decrease in Alona relative abundance following the marine flooding, likely reflecting a loss of A. quadrangularis, A. barbulata, and A. costata from the lake. A. circumfimbriata, Chydorus biovatus, C. brevilabris, and Bosmina spp. were abundant both before and after the saltwater intrusion, and Paralona pigra was present following the storm surge, but not prior to it. The most notable shift in Cladocera in the recent sedimentary record, however, occurred much earlier, with an increase in pelagic Bosmina taxa and a subsequent decrease in the benthic/littoral taxa Chydorus and Camptocercus, an assemblage shift that is consistent with a response to climate warming in this region, and strongly correlated to other changes in the lake inferred to be as a result of regional warming. 相似文献
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Daniel J. Utting John C. Gosse Samuel E. Kelley Kayla J. Vickers Brent C. Ward Michelle S. Trommelen 《Boreas: An International Journal of Quaternary Research》2016,45(3):439-454
The impact of the Laurentide Ice Sheet (LIS) deglaciation on Northern Hemisphere early Holocene climate can be evaluated only once a detailed chronology of ice history and sea‐level change is established. Foxe Peninsula is ideally situated on the northern boundary of Hudson Strait, and preserves a chronostratigraphy that provides important glaciological insights regarding changes in ice‐sheet position and relative sea level before and after the 8.2 ka cooling event. We utilized a combination of radiocarbon ages, adjusted with a new locally derived ΔR, and terrestrial in‐situ cosmogenic nuclide (TCN) exposure ages to develop a chronology for early‐Holocene events in the northern Hudson Strait. A marine limit at 192 m a.s.l., dated at 8.1–7.9 cal. ka BP, provides the timing of deglaciation following the 8.2 ka event, confirming that ice persisted at least north of Hudson Bay until then. A moraine complex and esker morphosequence, the Foxe Moraine, relates to glaciomarine outwash deltas and beaches at 160 m a.s.l., and is tightly dated at 7.6 cal. ka BP with a combination of shell dates and exposure ages on boulders. The final rapid collapse of Foxe Peninsula ice occurred by 7.1–6.9 cal. ka BP (radiocarbon dates and TCN depth profile age on an outwash delta), which supports the hypothesis that LIS melting contributed to the contemporaneous global sea‐level rise known as the Catastrophic Rise Event 3 (CRE‐3). 相似文献
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Samantha P. Vega C. Jason Williams Erin S. Brooks Frederick B. Pierson Eva K. Strand Peter R. Robichaud Robert E. Brown Mark S. Seyfried Kathleen A. Lohse Kayla Glossner Jennifer L. Pierce Clay Roehner 《地球表面变化过程与地形》2020,45(4):841-861
Wildfire is a natural component of sagebrush (Artemisia spp.) steppe rangelands that induces temporal shifts in plant community physiognomy, ground surface conditions, and erosion rates. Fire alteration of the vegetation structure and ground cover in these ecosystems commonly amplifies soil losses by wind- and water-driven erosion. Much of the fire-related erosion research for sagebrush steppe has focused on either erosion by wind over gentle terrain or water-driven erosion under high-intensity rainfall on complex topography. However, many sagebrush rangelands are geographically positioned in snow-dominated uplands with complex terrain in which runoff and sediment delivery occur primarily in winter months associated with cold-season hydrology. Current understanding is limited regarding fire effects on the interaction of wind- and cold-season hydrologic-driven erosion processes for these ecosystems. In this study, we evaluated fire impacts on vegetation, ground cover, soils, and erosion across spatial scales at a snow-dominated mountainous sagebrush site over a 2-year period post-fire. Vegetation, ground cover, and soil conditions were assessed at various plot scales (8 m2 to 3.42 ha) through standard field measures. Erosion was quantified through a network of silt fences (n = 24) spanning hillslope and side channel or swale areas, ranging from 0.003 to 3.42 ha in size. Sediment delivery at the watershed scale (129 ha) was assessed by suspended sediment samples of streamflow through a drop-box v-notch weir. Wildfire consumed nearly all above-ground live vegetation at the site and resulted in more than 60% bare ground (bare soil, ash, and rock) in the immediate post-fire period. Widespread wind-driven sediment loading of swales was observed over the first month post-fire and extensive snow drifts were formed in these swales each winter season during the study. In the first year, sediment yields from north- and south-facing aspects averaged 0.99–8.62 t ha−1 at the short-hillslope scale (~0.004 ha), 0.02–1.65 t ha−1 at the long-hillslope scale (0.02–0.46 ha), and 0.24–0.71 t ha−1 at the swale scale (0.65–3.42 ha), and watershed scale sediment yield was 2.47 t ha−1. By the second year post fire, foliar cover exceeded 120% across the site, but bare ground remained more than 60%. Sediment yield in the second year was greatly reduced across short- to long-hillslope scales (0.02–0.04 t ha−1), but was similar to first-year measures for swale plots (0.24–0.61 t ha−1) and at the watershed scale (3.05 t ha−1). Nearly all the sediment collected across all spatial scales was delivered during runoff events associated with cold-season hydrologic processes, including rain-on-snow, rain-on-frozen soils, and snowmelt runoff. Approximately 85–99% of annual sediment collected across all silt fence plots each year was from swales. The high levels of sediment delivered across hillslope to watershed scales in this study are attributed to observed preferential loading of fine sediments into swale channels by aeolian processes in the immediate post-fire period and subsequent flushing of these sediments by runoff from cold-season hydrologic processes. Our results suggest that the interaction of aeolian and cold-season hydrologic-driven erosion processes is an important component for consideration in post-fire erosion assessment and prediction and can have profound implications for soil loss from these ecosystems. © 2019 John Wiley & Sons, Ltd. 相似文献
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The effects of loess erosion on soil nutrients, plant diversity and plant quality in Negev desert wadis 总被引：1，自引：0，他引：1
Severe erosion, initiated by climatic changes during the Late Pleistocene-Early Holocene period and resultant declines in dust deposition, causes the formation of waterfalls during the winter floods in many wadi systems in the central Negev desert of Israel. In some areas, erosion of the original loess substrate has been complete, so that the underlying rock has been exposed. We examined the effects of this erosion in four wadis in the central Negev desert on soil nutrients, plant community structure and plant quality. We predicted that erosion has caused reductions in soil nutrients. Reductions in soil nutrients should result in reductions in plant cover. Furthermore, reduced soil nutrient availability should cause reductions in the nutrient status and quality of the plants growing there. In addition to the loss of biodiversity that may result, this erosion may result in economic hardship for the Bedouin peoples whose herds depend on these resources. In this study, there were significant negative effects of erosion on soil organic carbon, nitrate nitrogen and water-holding capacity, but not on soil phosphorus, conductivity or pH. Furthermore, there was a negative effect of soil erosion on an overall measure of soil quality derived from a principal components analysis in three of the four wadis we studied. Erosion resulted in an increase in plant species richness and significantly altered plant community structure in eroded areas of wadis. Increased plant species richness in eroded sites is consistent with the intermediate disturbance hypothesis of plant community structure. Plants growing in eroded areas did not differ in two quality indices (nitrogen content and digestibility), although plants typical of eroded areas had significantly lower levels of common digestion inhibitors (total polyphenols) and toxins (alkaloids) than plants from undisturbed sites. These last-mentioned results are contrary to our prediction and are consistent with the notion that plants growing in disturbed (e.g. eroded) sites maximize growth at the expense of investments in defense. 相似文献
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Brian King Jamie E. Shinn Kayla Yurco Kenneth R. Young Kelley A. Crews Meyer 《The Professional geographer》2019,71(1):29-38
Research within geography and related disciplines has directed much attention to the coupled interactions between social and ecological systems. These studies have usefully analyzed the multifaceted, temporal, and scalar dimensions of human–environment interactions and how future environmental change will continue to challenge human resource needs. Political ecology research has also made contributions in this regard, particularly by emphasizing livelihood systems, impacts of conservation and development, agricultural production, and environmental governance. Yet although political ecology research has contributed to socioecological systems scholarship, much of this work has been situated within dryland environments or marine ecosystems that have particular biophysical features. Comparatively, wetland environments that experience dynamic flooding regimes warrant further attention from political ecology. This article engages with the findings from an ongoing research project that is evaluating the impacts of flooding variability for rural livelihoods in the Okavango Delta of Botswana. We outline some of the main findings from this work by concentrating on two themes central to political ecology: access and governance. We conclude by arguing that the Okavango Delta should be understood as a hydrosocial waterscape that encompasses a variety of socioecological relationships within the region, as well as the power relations operating at a variety of scales that both produce and govern them. 相似文献
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Expansion of impervious surface cover results in “flashy” hydrologic response, elevated flood risk, and degraded water quality in urban watersheds. Stormwater management ponds (SWMPs) are often engineered into stream networks to mitigate these issues. A clearer understanding of how water is stored and released from SWMPs and SWMP-treated catchments is required to better represent these engineered systems in hydrological and water quality models of urban and urbanizing watersheds. Stable water isotopes were used to compare water age in SWMPs and SWMP-treated catchments in an urbanizing watershed. We sampled water biweekly from two SWMPs and five stream sites with varying land cover and stormwater control in their catchments. Two inverse transit time proxies (damping ratio and young water fraction) were computed along with the mean transit time (MTT) by sine–wave fitting for each SWMP and stream site using the δ18O and δ2H data. Water entering the SWMPs was consistently older (224 and 177 days) than water in or exiting the ponds (ranging from 46 to 91 days and 39 to 67 days, respectively). This finding is likely due to a combination of groundwater infiltration into broken sewer pipes that transport water into the ponds and a bias toward baseflow sampling. At the catchment scale, detention provided by SWMPs was not found to be more significant than the interactive effects of impervious cover, surficial geology, land use proportions, and catchment size in determining MTT. Overall, surficial geology explained the most variation in MTT among the seven sites. This study illustrates the potential for isotope-based approaches of water age to provide information on individual SWMP functioning and the influence of SWMPs on catchment-scale water movement. 相似文献
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Marine reservoir age is reported for Foxe Basin, Canada, during deglaciation of the Laurentide Ice Sheet. Radiocarbon (14C) measurements were made on pairs of contemporaneous molluscs and Salix (willow) macrofossils, yielding a mean marine reservoir age of 985 ± 10 14C a. Mean regional ΔR is calculated to be 615 ± 20 14C a relative to a mean global reservoir age of ca. 400 14C a. Previous studies in the Canadian Arctic that have been conducted on modern pre‐bomb molluscs give ΔR values of ca. 100–300 14C a. The difference between modern and deglacial reservoir ages indicates that ΔR in Foxe Basin has changed over time, which has implications for the reconstruction of past events based on marine 14C dates. We recalculate the timing of deglaciation of Hudson Strait with this new reservoir age and relate this to the 8.2 cal. ka event. We recommend that local ΔR be determined for the time period being examined whenever possible, and that in cases where this is impossible a ΔR value of 615 14C a be applied when calibrating marine samples from Foxe Basin and vicinity during deglaciation. Copyright © 2010 John Wiley & Sons, Ltd. 相似文献
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Kayla Iacovino Gordon Moore Kurt Roggensack Clive Oppenheimer Philip Kyle 《Contributions to Mineralogy and Petrology》2013,166(3):845-860
We present new equilibrium mixed-volatile (H2O–CO2) solubility data for a phonotephrite from Erebus volcano, Antarctica. H2O–CO2-saturated experiments were conducted at 400–700 MPa, 1,190 °C, and ~NNO + 1 in non-end-loaded piston cylinders. Equilibrium H2O–CO2 fluid compositions were determined using low-temperature vacuum manometry, and the volatile and major element compositions of the glassy run products were determined by Fourier transform infrared spectroscopy and electron microprobe. Results show that the phonotephrite used in this study will dissolve ~0.8 wt% CO2 at 700 MPa and a fluid composition of $ X_{{{\text{H}}_{ 2} {\text{O}}}} $ ~0.4, in agreement with previous experimental studies on mafic alkaline rocks. Furthermore, the dissolution of CO2 at moderate to high $ X_{{{\text{H}}_{ 2} {\text{O}}}}^{\text{fluid}} $ in our experiments exceeds that predicted using lower-pressure experiments on similar melts from the literature, suggesting a departure from Henrian behavior of volatiles in the melt at pressures above 400 MPa. With these data, we place new constraints on the modeling of Erebus melt inclusion and gas emission data and thus the interpretation of its magma plumbing system and the contributions of primitive magmas to passive and explosive degassing from the Erebus phonolite lava lake. 相似文献