Key publications
Puttock A, Graham HA, Ashe J, Luscombe DJ, Brazier RE (2021). Beaver dams attenuate flow: a multi-site study.
Hydrological Processes,
35(2).
Abstract:
Beaver dams attenuate flow: a multi-site study
Beavers can profoundly alter riparian environments, most conspicuously by creating dams and wetlands. Eurasian beaver (Castor fiber) populations are increasing and it has been suggested they could play a role in the provision of multiple ecosystem services, including natural flood management. Research at different scales, in contrasting ecosystems is required to establish to what extent beavers can impact on flood regimes. Therefore, this study determines whether flow regimes and flow responses to storm events were altered following the building of beaver dams and whether a flow attenuation effect could be significantly attributed to beaver activity. Four sites were monitored where beavers have been reintroduced in England. Continuous monitoring of hydrology, before and after beaver impacts, was undertaken on streams where beavers built sequences of dams. Stream orders ranged from 2nd to 4th, in both agricultural and forest-dominated catchments. Analysis of >1000 storm events, across four sites showed an overall trend of reduced total stormflow, increased peak rainfall to peak flow lag times and reduced peak flows, all suggesting flow attenuation, following beaver impacts. Additionally, reduced high flow to low flow ratios indicated that flow regimes were overall becoming less “flashy” following beaver reintroduction. Statistical analysis, showed the effect of beaver to be statistically significant in reducing peak flows with estimated overall reductions in peak flows from −0.359 to −0.065 m3 s−1 across sites. Analysis showed spatial and temporal variability in the hydrological response to beaver between sites, depending on the level of impact and seasonality. Critically, the effect of beavers in reducing peak flows persists for the largest storms monitored, showing that even in wet conditions, beaver dams can attenuate average flood flows by up to ca. 60%. This research indicates that beavers could play a role in delivering natural flood management.
Abstract.
Campbell-Palmer R, Puttock A, Wilson KA, Leow-Dyke A, Graham HA, Gaywood MJ, Brazier RE (2021). Using field sign surveys to estimate spatial distribution and territory dynamics following reintroduction of the Eurasian beaver to British river catchments.
RIVER RESEARCH AND APPLICATIONS,
37(3), 343-357.
Author URL.
Brazier RE, Puttock A, Graham HA, Auster RE, Davies KH, Brown CML (2020). Beaver: Nature's ecosystem engineers.
WIREs Water,
8(1).
Abstract:
Beaver: Nature's ecosystem engineers
AbstractBeavers have the ability to modify ecosystems profoundly to meet their ecological needs, with significant associated hydrological, geomorphological, ecological, and societal impacts. To bring together understanding of the role that beavers may play in the management of water resources, freshwater, and terrestrial ecosystems, this article reviews the state‐of‐the‐art scientific understanding of the beaver as the quintessential ecosystem engineer. This review has a European focus but examines key research considering both Castor fiber—the Eurasian beaver and Castor canadensis—its North American counterpart. In recent decades species reintroductions across Europe, concurrent with natural expansion of refugia populations has led to the return of C. fiber to much of its European range with recent reviews estimating that the C. fiber population in Europe numbers over 1.5 million individuals. As such, there is an increasing need for understanding of the impacts of beaver in intensively populated and managed, contemporary European landscapes. This review summarizes how beaver impact: (a) ecosystem structure and geomorphology, (b) hydrology and water resources, (c) water quality, (d) freshwater ecology, and (e) humans and society. It concludes by examining future considerations that may need to be resolved as beavers further expand in the northern hemisphere with an emphasis upon the ecosystem services that they can provide and the associated management that will be necessary to maximize the benefits and minimize conflicts.This article is categorized under:
Water and Life > Nature of Freshwater Ecosystems
Abstract.
Graham HA, Puttock A, Macfarlane WW, Wheaton JM, Gilbert JT, Campbell-Palmer R, Elliott M, Gaywood MJ, Anderson K, Brazier RE, et al (2020). Modelling Eurasian beaver foraging habitat and dam suitability, for predicting the location and number of dams throughout catchments in Great Britain.
European Journal of Wildlife Research,
66(3).
Abstract:
Modelling Eurasian beaver foraging habitat and dam suitability, for predicting the location and number of dams throughout catchments in Great Britain
AbstractEurasian beaver (Castor fiber) populations are expanding across Europe. Depending on location, beaver dams bring multiple benefits and/or require management. Using nationally available data, we developed: a Beaver Forage Index (BFI), identifying beaver foraging habitat, and a Beaver Dam Capacity (BDC) model, classifying suitability of river reaches for dam construction, to estimate location and number of dams at catchment scales. Models were executed across three catchments, in Great Britain (GB), containing beaver. An area of 6747 km2 was analysed for BFI and 16,739 km of stream for BDC. Field surveys identified 258 km of channel containing beaver activity and 89 dams, providing data to test predictions. Models were evaluated using a categorical binomial Bayesian framework to calculate probability of foraging and dam construction. BFI and BDC models successfully categorised the use of reaches for foraging and damming, with higher scoring reaches being preferred. Highest scoring categories were ca. 31 and 79 times more likely to be used than the lowest for foraging and damming respectively. Zero-inflated negative binomial regression showed that modelled dam capacity was significantly related (p = 0.01) to observed damming and was used to predict numbers of dams that may occur. Estimated densities of dams, averaged across each catchment, ranged from 0.4 to 1.6 dams/km, though local densities may be up to 30 dams/km. These models provide fundamental information describing the distribution of beaver foraging habitat, where dams may be constructed and how many may occur. This supports the development of policy and management concerning the reintroduction and recolonisation of beaver.
Abstract.
Brazier RE, Elliott M, Andison E, Auster RE, Bridgewater S, Burgess P, Chant J, Graham H, Knott E, Puttock AK, et al (2020).
River Otter Beaver Trial: Science & Evidence Report. Devon, River Otter Beaver Trial.
Author URL.
Auster R, Puttock A, Brazier R (2019). Unravelling perceptions of Eurasian beaver reintroduction in Great Britain. AREA
Publications by year
In Press
Puttock A (In Press). Exploring the dynamics of flow attenuation at a beaver dam sequence. Hydrological Processes
2023
Auster RE, Puttock AK, Barr SW, Brazier RE (2023). Learning to live with reintroduced species: beaver management groups are an adaptive <i>process</i>.
Restoration Ecology,
31(5).
Abstract:
Learning to live with reintroduced species: beaver management groups are an adaptive process
In anthropogenic landscapes, wildlife reintroductions are likely to result in interactions between people and reintroduced species. People living in the vicinity may have little familiarity with the reintroduced species or associated management, so will need to learn to live with the species in a new state of “Renewed Coexistence.” in England, Eurasian beavers (Castor fiber) are being reintroduced and U.K. Government agencies are currently considering their national approach to reintroduction and management. Early indications are this will include requirement for “Beaver Management Groups” (BMGs) to engage with local stakeholders. This policy paper reports on qualitative research that captured lessons from the governance of two existing BMGs in Devon (south‐west England), drawing on both a prior study and new interview data. Through the analysis, we identified that BMGs are not a fixed structure, but an adaptive process. This consists of three stages (Formation, Functioning, and Future?), influenced by resource availability and national policy direction. We argue that, where they are used, Species‐specific Management Groups could provide a “front line” for the integration of reintroduced species into modern landscapes, but their role or remit could be scaled back over time and integrated into existing structures or partnerships to reduce pressure on limited resources, as knowledge of reintroduced species (such as beaver) grows and its presence becomes “normalized.” There must be sufficient flexibility in forthcoming policy to minimize constraint on the adaptive nature of BMGs and similar groups for other reintroduced species, if they are to facilitate a sustainable coexistence.
Abstract.
Gatis N, Benaud P, Anderson K, Ashe J, Grand-Clement E, Luscombe DJ, Puttock A, Brazier RE (2023). Peatland restoration increases water storage and attenuates downstream stormflow but does not guarantee an immediate reversal of long-term ecohydrological degradation.
Sci Rep,
13(1).
Abstract:
Peatland restoration increases water storage and attenuates downstream stormflow but does not guarantee an immediate reversal of long-term ecohydrological degradation.
Peatland restoration is experiencing a global upsurge as a tool to protect and provide various ecosystem services. As the range of peatland types being restored diversifies, do previous findings present overly optimistic restoration expectations? in an eroding and restored upland peatland we assessed short-term (0-4 year) effects of restoration on ecohydrological functions. Restoration significantly reduced discharge from the site, transforming peat pans into pools. These retained surface water over half the time and were deeper during wet periods than before. In the surrounding haggs water tables stabilised, as drawdown during dry conditions reduced, increasing the saturated peat thickness. Despite these changes, there were no effects on photosynthesis, ecosystem respiration or dissolved organic carbon loads leaving the site. Soil respiration did not decrease as water tables rose, but methane emissions were higher from rewet pools. Restoration has had a dramatic effect on hydrology, however, consequent changes in other ecosystem functions were not measured in the 4 years after restoration. Whilst restoration is crucial in halting the expansion of degraded peatland areas, it is vital that practitioners and policymakers advocating for restoration are realistic about the expected outcomes and timescales over which these outcomes may manifest.
Abstract.
Author URL.
Puttock A, Newman M, Graham H, Elliott M, Chant J, Auster R, Brazier R (2023). Positive coexistence of water voles and beaver: water vole expansion in a beaver engineered wetland.
Auster RE, Puttock A, Bradbury G, Brazier R (2023). Should individual animals be given names in wildlife reintroductions?.
People and Nature,
5(4), 1110-1118.
Abstract:
Should individual animals be given names in wildlife reintroductions?
Individual animals are often given names by humans. For example, names are attributed to domestic animals to acknowledge their closeness to people, some research studies use names to identify differences between individuals in a study group, or zoos often use names to tell stories that attract public or media attention. Publicly naming individual animals can provide opportunities in conservation, but there are also risks. In this perspective we exemplify such opportunities and risks in the context of wildlife reintroductions. We draw on examples and observations from our experience researching Eurasian beaver Castor fiber reintroduction in England, to encourage careful thinking before publicly attributing a name to an individual in reintroduction projects. Naming individuals in reintroduction can: be a low-cost engagement tool; help people relate to unfamiliar reintroduced species; encourage local ownership of reintroduction projects; enable an effective tool for communicating information about the species and ways to coexist; or support creative or cultural expression. Yet naming individuals in reintroduction could: risk misrepresentation of natural species characteristics; make it challenging to normalise the sense that the reintroduced species is a wild animal; unintentionally imply that humans have ownership or power over the animal; cause distraction from establishing viable populations due to focus on the individual; or result in human investment in individual animals, which may have influence on reintroduction outcomes if that animal later comes to harm or dies (naturally or otherwise). Synthesis and Applications. We argue there is more to the act of naming individuals than may first appear. If considering doing so, we call for careful thought about whether it is appropriate and how to go about it. While we intentionally refrain from concluding whether ‘to name or not to name’, we call for careful, informative, message framing that takes advantage of the opportunities and is prepared for future circumstances, when naming of individuals does take place. Read the free Plain Language Summary for this article on the Journal blog.
Abstract.
Bradbury G, Puttock A, Coxon G, Clarke S, Brazier RE (2023). Testing a novel sonar-based approach for measuring water depth and monitoring sediment storage in beaver ponds.
RIVER RESEARCH AND APPLICATIONS,
39(2), 266-273.
Author URL.
2022
Graham H, Puttock A, Elliott M, Anderson K, Brazier R (2022). Exploring the causes of flow attenuation at a beaver dam sequence.
Abstract:
Exploring the causes of flow attenuation at a beaver dam sequence.
Beavers influence hydrology by constructing woody dams. Using a before
after control impact experimental design, we quantified the effects of a
beaver dam sequence on the flow regime of a stream in SW England.
Building upon our previous research (Puttock et al. 2021), we consider
the mechanisms that underpin flow attenuation in beaver wetlands.
Rainfall-driven hydrological events were extracted between 2009 and
2020, for the impacted (n=612) and control (n=634) catchments, capturing
events seven years before and three years after beaver occupancy, at the
impacted site. General additive models were used to describe average
hydrograph geometry across all events. After beaver occupancy, Lag times
increased by 55.9% and declined by 17.5% in impacted and control
catchments, respectively. Flow duration curve analysis showed a larger
reduction in frequency of high flows, following beaver dam construction,
with declines of Q5 exceedance levels of 33% and 15% for impact and
control catchments, respectively. Using event total rainfall to predict
peak flow, five generalised linear models were fitted to test the
hypothesis that beaver dams attenuate flow, to a greater degree, with
larger storm magnitude. The best performing model showed we can have
high confidence that beaver dams attenuated peak flows, with increasing
magnitude, up to between 0.5-2.5 m. s
for the 94. percentile of event
total rainfall; but we cannot confidently detect attenuation beyond the
97. percentile. Increasing flow attenuation, with
event magnitude, is attributed to transient floodplain storage in low
gradient/profile floodplain valleys. These findings support the
assertion that beaver dams restore attenuated flows. However, with
long-term datasets of extreme hydrological events lacking, it is
challenging to predict the effect of beaver dams during extreme events
with high precision. Beaver dams will have spatially variable impacts on
hydrological processes, requiring further investigation to quantify
responses to dams across differing landscapes and scales.
Abstract.
Graham HA, Puttock AK, Elliott M, Anderson K, Brazier RE (2022). Exploring the dynamics of flow attenuation at a beaver dam sequence. Hydrological Processes, 36(11).
Graham HA, Puttock A, Chant J, Elliott M, Campbell‐Palmer R, Anderson K, Brazier RE (2022). Monitoring, modelling and managing beaver (Castor fiber) populations in the River Otter catchment, Great Britain. Ecological Solutions and Evidence, 3(3).
2021
Puttock A, Graham HA, Ashe J, Luscombe DJ, Brazier RE (2021). Beaver dams attenuate flow: a multi-site study.
Hydrological Processes,
35(2).
Abstract:
Beaver dams attenuate flow: a multi-site study
Beavers can profoundly alter riparian environments, most conspicuously by creating dams and wetlands. Eurasian beaver (Castor fiber) populations are increasing and it has been suggested they could play a role in the provision of multiple ecosystem services, including natural flood management. Research at different scales, in contrasting ecosystems is required to establish to what extent beavers can impact on flood regimes. Therefore, this study determines whether flow regimes and flow responses to storm events were altered following the building of beaver dams and whether a flow attenuation effect could be significantly attributed to beaver activity. Four sites were monitored where beavers have been reintroduced in England. Continuous monitoring of hydrology, before and after beaver impacts, was undertaken on streams where beavers built sequences of dams. Stream orders ranged from 2nd to 4th, in both agricultural and forest-dominated catchments. Analysis of >1000 storm events, across four sites showed an overall trend of reduced total stormflow, increased peak rainfall to peak flow lag times and reduced peak flows, all suggesting flow attenuation, following beaver impacts. Additionally, reduced high flow to low flow ratios indicated that flow regimes were overall becoming less “flashy” following beaver reintroduction. Statistical analysis, showed the effect of beaver to be statistically significant in reducing peak flows with estimated overall reductions in peak flows from −0.359 to −0.065 m3 s−1 across sites. Analysis showed spatial and temporal variability in the hydrological response to beaver between sites, depending on the level of impact and seasonality. Critically, the effect of beavers in reducing peak flows persists for the largest storms monitored, showing that even in wet conditions, beaver dams can attenuate average flood flows by up to ca. 60%. This research indicates that beavers could play a role in delivering natural flood management.
Abstract.
Campbell-Palmer R, Puttock A, Wilson KA, Leow-Dyke A, Graham HA, Gaywood MJ, Brazier RE (2021). Using field sign surveys to estimate spatial distribution and territory dynamics following reintroduction of the Eurasian beaver to British river catchments.
RIVER RESEARCH AND APPLICATIONS,
37(3), 343-357.
Author URL.
2020
Brazier RE, Puttock A, Graham HA, Auster RE, Davies KH, Brown CML (2020). Beaver: Nature's ecosystem engineers.
WIREs Water,
8(1).
Abstract:
Beaver: Nature's ecosystem engineers
AbstractBeavers have the ability to modify ecosystems profoundly to meet their ecological needs, with significant associated hydrological, geomorphological, ecological, and societal impacts. To bring together understanding of the role that beavers may play in the management of water resources, freshwater, and terrestrial ecosystems, this article reviews the state‐of‐the‐art scientific understanding of the beaver as the quintessential ecosystem engineer. This review has a European focus but examines key research considering both Castor fiber—the Eurasian beaver and Castor canadensis—its North American counterpart. In recent decades species reintroductions across Europe, concurrent with natural expansion of refugia populations has led to the return of C. fiber to much of its European range with recent reviews estimating that the C. fiber population in Europe numbers over 1.5 million individuals. As such, there is an increasing need for understanding of the impacts of beaver in intensively populated and managed, contemporary European landscapes. This review summarizes how beaver impact: (a) ecosystem structure and geomorphology, (b) hydrology and water resources, (c) water quality, (d) freshwater ecology, and (e) humans and society. It concludes by examining future considerations that may need to be resolved as beavers further expand in the northern hemisphere with an emphasis upon the ecosystem services that they can provide and the associated management that will be necessary to maximize the benefits and minimize conflicts.This article is categorized under:
Water and Life > Nature of Freshwater Ecosystems
Abstract.
Graham HA, Puttock A, Macfarlane WW, Wheaton JM, Gilbert JT, Campbell-Palmer R, Elliott M, Gaywood MJ, Anderson K, Brazier RE, et al (2020). Modelling Eurasian beaver foraging habitat and dam suitability, for predicting the location and number of dams throughout catchments in Great Britain.
European Journal of Wildlife Research,
66(3).
Abstract:
Modelling Eurasian beaver foraging habitat and dam suitability, for predicting the location and number of dams throughout catchments in Great Britain
AbstractEurasian beaver (Castor fiber) populations are expanding across Europe. Depending on location, beaver dams bring multiple benefits and/or require management. Using nationally available data, we developed: a Beaver Forage Index (BFI), identifying beaver foraging habitat, and a Beaver Dam Capacity (BDC) model, classifying suitability of river reaches for dam construction, to estimate location and number of dams at catchment scales. Models were executed across three catchments, in Great Britain (GB), containing beaver. An area of 6747 km2 was analysed for BFI and 16,739 km of stream for BDC. Field surveys identified 258 km of channel containing beaver activity and 89 dams, providing data to test predictions. Models were evaluated using a categorical binomial Bayesian framework to calculate probability of foraging and dam construction. BFI and BDC models successfully categorised the use of reaches for foraging and damming, with higher scoring reaches being preferred. Highest scoring categories were ca. 31 and 79 times more likely to be used than the lowest for foraging and damming respectively. Zero-inflated negative binomial regression showed that modelled dam capacity was significantly related (p = 0.01) to observed damming and was used to predict numbers of dams that may occur. Estimated densities of dams, averaged across each catchment, ranged from 0.4 to 1.6 dams/km, though local densities may be up to 30 dams/km. These models provide fundamental information describing the distribution of beaver foraging habitat, where dams may be constructed and how many may occur. This supports the development of policy and management concerning the reintroduction and recolonisation of beaver.
Abstract.
Brazier RE, Elliott M, Andison E, Auster RE, Bridgewater S, Burgess P, Chant J, Graham H, Knott E, Puttock AK, et al (2020).
River Otter Beaver Trial: Science & Evidence Report. Devon, River Otter Beaver Trial.
Author URL.
2019
Auster R, Puttock A, Brazier R (2019). Unravelling perceptions of Eurasian beaver reintroduction in Great Britain. AREA
2018
Puttock A, Brazier R, Graham H, Carless D (2018). Sediment and nutrient storage in a beaver engineered wetland. Earth Surface Processes and Landforms
2017
Puttock A, Graham HA, Cunliffe AM, Elliott M, Brazier RE (2017). Eurasian beaver activity increases water storage, attenuates flow and mitigates diffuse pollution from intensively-managed grasslands. Science of the Total Environment, 576, 430-443.
2016
Cunliffe AM, Puttock AK, Turnbull L, Wainwright J, Brazier RE (2016). Dryland, calcareous soils store (and lose) significant quantities of near‐surface organic carbon.
Journal of Geophysical Research: Earth Surface,
121(4), 684-702.
Abstract:
Dryland, calcareous soils store (and lose) significant quantities of near‐surface organic carbon
AbstractSemiarid ecosystems are susceptible to changes in dominant vegetation which may have significant implications for terrestrial carbon dynamics. The present study examines the distribution of organic carbon (OC) between particle size fractions in near‐surface (0–0.05 m) soil and the water erosion‐induced redistribution of particle‐associated OC over a grass‐shrub ecotone, in a semiarid landscape, subject to land degradation. Coarse (>2 mm) particles have comparable average OC concentrations to the fine (<2 mm) particles, accounting for ~24–38% of the OC stock in the near‐surface soil. This may be due to aggregate stabilization by precipitated calcium carbonate in these calcareous arid soils. Critically, standard protocols assuming that coarse fraction particles contain no OC are likely to underestimate soil OC stocks substantially, especially in soils with strongly stabilized aggregates. Sediment eroded from four hillslope scale (10 × 30 m) sites during rainstorm events was monitored over four annual monsoon seasons. Eroded sediment was significantly enriched in OC; enrichment increased significantly across the grass‐shrub ecotone and appears to be an enduring phenomenon probably sustained through the dynamic replacement of preferentially removed organic matter. The average erosion‐induced OC event yield increased sixfold across the ecotone from grass‐dominated to shrub‐dominated ecosystems, due to both greater erosion and greater OC enrichment. This erosional pathway is rarely considered when comparing the carbon budgets of grasslands and shrublands, yet this accelerated efflux of OC may be important for long‐term carbon storage potentials of dryland ecosystems.
Abstract.
2015
Puttock A, Cunliffe AM, Anderson K, Brazier RE (2015). Aerial photography collected with a multirotor drone reveals impact of Eurasian beaver reintroduction on ecosystem structure.
Journal of Unmanned Vehicle Systems Author URL.
2014
Hochstrasser T, Millington JA, Papanastasis V, Parsons A, Roggero P, Brazier R, Estrany J, Farina A, Puttock A (2014). The Study of Land Degradation in Drylands: State of the Art. In Mueller EN, Wainwright J, Parsons AJ, Turnbull L (Eds.)
Patterns of Land Degradation in Drylands, Springer Netherlands, 13-54.
Author URL.
Puttock A, Dungait JAJ, Macleod CJA, Bol R, Brazier RE (2014). Woody plant encroachment into grasslands leads to accelerated erosion of previously stable organic carbon from dryland soils.
Journal of Geophysical Research: Biogeosciences,
119(12), 2345-2357.
Abstract:
Woody plant encroachment into grasslands leads to accelerated erosion of previously stable organic carbon from dryland soils
Drylands worldwide are experiencing rapid and extensive environmental change, concomitant with the encroachment of woody vegetation into grasslands. Woody encroachment leads to changes in both the structure and function of dryland ecosystems and has been shown to result in accelerated soil erosion and loss of soil nutrients. Covering 40% of the terrestrial land surface, dryland environments are of global importance, both as a habitat and a soil carbon store. Relationships between environmental change, soil erosion, and the carbon cycle are uncertain. There is a clear need to further our understanding of dryland vegetation change and impacts on carbon dynamics. Here two grass-to-woody ecotones that occur across large areas of the southwestern United States are investigated. This study takes a multidisciplinary approach, combining ecohydrological monitoring of structure and function and a dual-proxy biogeochemical tracing approach using the unique natural biochemical signatures of the vegetation. Results show that following woody encroachment, not only do these drylands lose significantly more soil and organic carbon via erosion but that this includes significant amounts of legacy organic carbon which would previously have been stable under grass cover. Results suggest that these dryland soils may not act as a stable organic carbon pool, following encroachment and that accelerated erosion of carbon, driven by vegetation change, has important implications for carbon dynamics.
Abstract.
2013
Puttock A, Macleod CJA, Bol R, Sessford P, Dungait J, Brazier RE (2013). Changes in ecosystem structure, function and hydrological connectivity control water, soil and carbon losses in semi-arid grass to woody vegetation transitions.
Earth Surface Processes and Landforms,
38(13), 1602-1611.
Abstract:
Changes in ecosystem structure, function and hydrological connectivity control water, soil and carbon losses in semi-arid grass to woody vegetation transitions
Connectivity has recently emerged as a key concept for understanding hydrological response to vegetation change in semi-arid environments, providing an explanatory link between abiotic and biotic, structure and function. Reduced vegetation cover following woody encroachment, generally promotes longer, more connected overland flow pathways, which has the potential to result in an accentuated rainfall-runoff response and fluxes of both soil erosion and carbon. This paper investigates changing hydrological connectivity as an emergent property of changing ecosystem structure over two contrasting semi-arid grass to woody vegetation transitions in New Mexico, USA. Vegetation structure is quantified to evaluate if it can be used to explain observed variations in water, sediment and carbon fluxes. Hydrological connectivity is quantified using a flow length metric, combining topographic and vegetation cover data. Results demonstrate that the two woody-dominated sites have significantly longer mean flowpath lengths (4·3m), than the grass-dominated sites (2·4m). Mean flowpath lengths illustrate a significant positive relationship with the functional response. The woody-dominated sites lost more water, soil and carbon than their grassland counterparts. Woody sites erode more, with mean event-based sediment yields of 1203g, compared to 295g from grasslands. In addition, the woody sites lost more organic carbon, with mean event yields of 39g compared to 5g from grassland sites. Finally, hydrological connectivity (expressed as mean flowpath length) is discussed as a meaningful measure of the interaction between structure and function and how this manifests under the extreme rainfall that occurs in semi-arid deserts. In combination with rainfall characteristics, connectivity emerges as a useful tool to explain the impact of vegetation change on water, soil and carbon losses across semi-arid environments.Copyright © 2013 John Wiley & Sons, Ltd.
Abstract.
2012
Puttock A, Dungait JAJ, Bol R, Dixon ER, Macleod CJA, Brazier RE (2012). Stable carbon isotope analysis of fluvial sediment fluxes over two contrasting C<inf>4</inf>-C<inf>3</inf> semi-arid vegetation transitions.
Rapid Communications in Mass Spectrometry,
26(20), 2386-2392.
Abstract:
Stable carbon isotope analysis of fluvial sediment fluxes over two contrasting C4-C3 semi-arid vegetation transitions
RATIONALE: Globally, many drylands are experiencing the encroachment of woody vegetation into grasslands. These changes in ecosystem structure and processes can result in increased sediment and nutrient fluxes due to fluvial erosion. As these changes are often accompanied by a shift from C4 to C3 vegetation with characteristic δ13C values, stable isotope analysis provides a promising mechanism for tracing these fluxes. METHODS: Input vegetation, surface sediment and fluvially eroded sediment samples were collected across two contrasting C4-C3 dryland vegetation transitions in New Mexico, USA. Isotope ratio mass spectrometric analyses were performed using a Carlo Erba NA2000 analyser interfaced to a SerCon 20-22 isotope ratio mass spectrometer to determine bulk δ13C values. RESULTS: Stable isotope analyses of contemporary input vegetation and surface sediments over the monitored transitions showed significant differences (p
Abstract.
