scholarly journals Natural history features of the high-country and drylands of the South Island, New Zealand

2018 ◽  
pp. 27-32
Author(s):  
William G Lee

The high-country and dryland zone of the South Island of New Zealand includes the Southern Alpsand eastern mountains and basins. Formed by post-Pliocene tectonic, glacial and alluvial processes, theseareas contain a range of landforms across extreme climatic gradients. Diverse habitats support plantsand animals which have a distinctive and long natural history. New Zealand’s short (c. 700 years) historyof human land use has been highly disruptive for indigenous biodiversity. We have misunderstood theeco-evolutionary vulnerabilities of the native biota, the extent of environmental limits, and the impacts ofintroduced weeds and pests. Recent large-scale capture of water and addition of nutrients for agriculture areexcluding indigenous biodiversity in many ecosystems. Predicted climate change and competition for waterresources will exacerbate agricultural impacts, but the remaining indigenous biodiversity can be resilient ifrepresentative areas are protected.

2011 ◽  
Vol 8 (4) ◽  
pp. 7621-7655 ◽  
Author(s):  
S. Stoll ◽  
H. J. Hendricks Franssen ◽  
R. Barthel ◽  
W. Kinzelbach

Abstract. Future risks for groundwater resources, due to global change are usually analyzed by driving hydrological models with the outputs of climate models. However, this model chain is subject to considerable uncertainties. Given the high uncertainties it is essential to identify the processes governing the groundwater dynamics, as these processes are likely to affect groundwater resources in the future, too. Information about the dominant mechanisms can be achieved by the analysis of long-term data, which are assumed to provide insight in the reaction of groundwater resources to changing conditions (weather, land use, water demand). Referring to this, a dataset of 30 long-term time series of precipitation dominated groundwater systems in northern Switzerland and southern Germany is collected. In order to receive additional information the analysis of the data is carried out together with hydrological model simulations. High spatio-temporal correlations, even over large distances could be detected and are assumed to be related to large-scale atmospheric circulation patterns. As a result it is suggested to prefer innovative weather-type-based downscaling methods to other stochastic downscaling approaches. In addition, with the help of a qualitative procedure to distinguish between meteorological and anthropogenic causes it was possible to identify processes which dominated the groundwater dynamics in the past. It could be shown that besides the meteorological conditions, land use changes, pumping activity and feedback mechanisms governed the groundwater dynamics. Based on these findings, recommendations to improve climate change impact studies are suggested.


2019 ◽  
Vol 11 (3) ◽  
pp. 609-622 ◽  
Author(s):  
Saeideh Maleki ◽  
Saeid Soltani Koupaei ◽  
Alireza Soffianian ◽  
Sassan Saatchi ◽  
Saeid Pourmanafi ◽  
...  

Abstract Negative impacts of climate change on ecosystems have been increasing, and both the intensification and the mitigation of these impacts are strongly linked with human activities. Management and reduction of human-induced disturbances on ecosystems can mitigate the effects of climate change and enhance the ecosystem recovery process. Here, we investigate coupled human and climate effects on the wetland ecosystem of the lower Helmand basin from 1977 to 2014. Using time series climate-variable data and land-use changes from Landsat time series imagery, we compared changes in ecosystem status between the upstream and downstream regions. Results show that despite a strong and prolonged drought in the region, the upstream region of the lower Helmand basin remained dominated by agriculture, causing severe water stress on the Hamoun wetlands downstream. The loss of available water in wetlands was followed by large-scale land abandonment in rural areas, migration to the cities, and increasing unemployment and economic hardship. Our results suggest that unsustainable land-use policies in the upstream region, combined with synergistic effects of human activities and climate in lower Helmand basin, have exacerbated the effects of water stress on local inhabitants in the downstream region.


Water ◽  
2018 ◽  
Vol 10 (10) ◽  
pp. 1438 ◽  
Author(s):  
Luis Morales-Marín ◽  
Howard Wheater ◽  
Karl-Erich Lindenschmidt

Climate and land-use changes modify the physical functioning of river basins and, in particular, influence the transport of nutrients from land to water. In large-scale basins, where a variety of climates, topographies, soil types and land uses co-exist to form a highly heterogeneous environment, a more complex nutrient dynamic is imposed by climate and land-use changes. This is the case of the South Saskatchewan River (SSR) that, along with the North Saskatchewan River, forms one of the largest river systems in western Canada. The SPAtially Referenced Regression On Watershed (SPARROW) model is therefore implemented to assess water quality in the basin, in order to describe spatial and temporal patterns and identify those factors and processes that affect water quality. Forty-five climate and land-use change scenarios comprehended by five General Circulation Models (GCMs) and three Representative Concentration Pathways (RCPs) were incorporated into the model to explain how total nitrogen (TN) and total phosphorus (TP) export could vary across the basin in 30, 60 and 90 years from now. According to model results, annual averages of TN and TP export in the SSR are going to increase in the range 0.9–1.28 kg km − 2 year − 1 and 0.12–0.17 kg km − 2 year − 1 , respectively, by the end of the century, due to climate and land-use changes. Higher increases of TP compared to TN are expected since TP and TN are going to increase ∼36% and ∼21%, respectively, by the end of the century. This research will support management plans in order to mitigate nutrient export under future changes of climate and land use.


2019 ◽  
Vol 11 (17) ◽  
pp. 1980
Author(s):  
Benjamin Robb ◽  
Qiongyu Huang ◽  
Joseph Sexton ◽  
David Stoner ◽  
Peter Leimgruber

Migration is a valuable life history strategy for many species because it enables individuals to exploit spatially and temporally variable resources. Globally, the prevalence of species’ migratory behavior is decreasing as individuals forgo migration to remain resident year-round, an effect hypothesized to result from anthropogenic changes to landscape dynamics. Efforts to conserve and restore migrations require an understanding of the ecological characteristics driving the behavioral tradeoff between migration and residence. We identified migratory and resident behaviors of 42 mule deer (Odocoileus hemionus) based on GPS locations and correlated their locations to remotely sensed indicators of forage quality, land cover, snow cover, and human land use. The model classified mule deer seasonal migratory and resident niches with an overall accuracy of 97.8% and cross-validated accuracy of 81.2%. The distance to development was the most important variable in discriminating in which environments these behaviors occur, with resident niche space most often closer to developed areas than migratory niches. Additionally, snow cover in December was important for discriminating summer migratory niches. This approach demonstrates the utility of niche analysis based on remotely sensed environmental datasets and provides empirical evidence of human land use impacts on large-scale wildlife migrations.


2020 ◽  
Vol 5 (11) ◽  
pp. 92 ◽  
Author(s):  
Rick Kool ◽  
Judy Lawrence ◽  
Martin Drews ◽  
Robert Bell

Sea-level rise increasingly affects low-lying and exposed coastal communities due to climate change. These communities rely upon the delivery of stormwater and wastewater services which are often co-located underground in coastal areas. Due to sea-level rise and associated compounding climate-related hazards, managing these networks will progressively challenge local governments as climate change advances. Thus, responsible agencies must reconcile maintaining Levels of Service as the impacts of climate change worsen over the coming decades and beyond. A critical question is whether such networks can continue to be adapted/protected over time to retain Levels of Service, or whether eventual retreat may be the only viable adaptation option? If so, at what performance threshold? In this paper, we explore these questions for stormwater and wastewater, using a dynamic adaptive pathway planning (DAPP) approach designed to address thresholds and increasing risk over time. Involving key local stakeholders, we here use DAPP to identify thresholds for stormwater and wastewater services and retreat options, and for developing a comprehensive and area-specific retreat strategy comprising pathway portfolios, retreat phases, potential land use changes, and for exploring pathway conflicts and synergies. The result is a prototype for an area near Wellington, New Zealand, where a managed retreat of water infrastructure is being considered at some future juncture. Dynamic adaptive strategies for managed retreats can help to reduce future disruption from coastal flooding, signal land use changes early, inform maintenance, and allow for gradual budget adjustments by the agencies that can manage expenditure over time. We present this stepwise process in a pathway form that can be communicated spatially and visually, thereby making a retreat a more manageable, sequenced, adaptation option for water agencies, and the communities they serve.


2020 ◽  
Vol 29 (8) ◽  
pp. 649 ◽  
Author(s):  
Mauro E. González ◽  
Ariel A. Muñoz ◽  
Álvaro González-Reyes ◽  
Duncan A. Christie ◽  
Jason Sibold

Historical fire regimes are critical for understanding the potential effects of changing climate and human land-use on forest landscapes. Fire is a major disturbance process affecting the Andean Araucaria forest landscape in north-west Patagonia. The main goals of this study were to reconstruct the fire history of the Andean Araucaria–Nothofagus forests and to evaluate the coupled influences of climate and humans on fire regimes. Reconstructions of past fires indicated that the Araucaria forest landscape has been shaped by widespread, stand-replacing fires favoured by regional interannual climate variability related to major tropical and extratropical climate drivers in the southern hemisphere. Summer precipitation and streamflow reconstructions tended to be below average during fire years. Fire events were significantly related to positive phases of the Southern Annular Mode and to warm and dry summers following El Niño events. Although Euro-Chilean settlement (1883–1960) resulted in widespread burning, cattle ranching by Pehuenche Native Americans during the 18th and 19th centuries also appears to have changed the fire regime. In the context of climate change, two recent widespread wildfires (2002 and 2015) affecting Araucaria forests appear to be novel and an early indication of a climate change driven shift in fire regimes in north-west Patagonia.


2009 ◽  
Vol 15 (3) ◽  
pp. 601-612 ◽  
Author(s):  
MARK A. COCHRANE ◽  
CHRISTOPHER P. BARBER

2020 ◽  
Author(s):  
Stephanie Horion ◽  
Paulo Bernardino ◽  
Wanda De Keersmaecker ◽  
Rasmus Fensholt ◽  
Stef Lhermitte ◽  
...  

<p>Pressures on dryland ecosystems are ever growing. Large-scale vegetation die-offs, biodiversity loss and loss in ecosystem services are reported as a result of unsustainable land use, climate change and extreme events. Yet major uncertainties remain regarding our capability to accurately assess on-going land changes, as well as to comprehensively attribute drivers to these changes. Indeed ecosystem response to external pressures is often complex (e.g. non-linear) and non-unique (i.e. same response, different drivers). Besides critical knowledge on ecosystem stability and coping capacities to extreme events has still to be consolidated.</p><p>Recent advances in time series analysis and in the assessment of breakpoint open a new door in ecosystem research as they allow for the detection of turning points and tipping points in ecosystem development (Horion et al., 2016 and 2019). Identifying ecosystems that have significantly changed their way of functioning, i.e. that have tipped to a new functioning state, is of crucial importance for Ecology studies. These extremes cases of vegetation instability are golden mines for researches that try to understand how resilient are ecosystems to climate change and to non-sustainable use of land.</p><p>This is precisely what the U-TURN project is about:</p><ul><li><strong>Developing methods for detecting turning points in dryland ecosystem functioning</strong>; Here we defined <em>turning point</em> in ecosystem functioning as a key moment in the ecosystem development where its functioning is significantly changed or altered without implying the irreversibility of the process (Horion et al. (2016)), by opposition to the term ‘<em>tipping point</em>’ that implies irreversibility (Lenton et al. 2008).</li> <li><strong>Studying the contribution of climate and human pressure</strong> (e.g. land-use intensification, human induced land soil degradation) in pushing the ecosystem outside its safe operating space ; Here we used Earth Observation techniques coupled with Dynamic Vegetation Models to get process-based insights on the drivers of the observed changes in ecosystem functioning.</li> <li>Exploring whether <strong>early warning signal of turning points</strong> can be identified.</li> </ul><p>During our talk, we will present key methodological advances being achieved within the U-TURN project, and showcase some of our major findings in relation to abrupt changes in dryland ecosystem functioning.</p><p><strong>References:</strong></p><p>Horion, S., Ivits, E., De Keersmaecker, W., Tagesson, T., Vogt, J., & Fensholt, R. (2019). Mapping European ecosystem change types in response to land‐use change, extreme climate events, and land degradation. Land Degradation & Development, 30(8), 951-963. doi:10.1002/ldr.3282</p><p>Horion, S., Prishchepov, A. V., Verbesselt, J., de Beurs, K., Tagesson, T., & Fensholt, R. (2016). Revealing turning points in ecosystem functioning over the Northern Eurasian agricultural frontier. Global Change Biology, 22(8), 2801-2817. doi:10.1111/gcb.13267</p><p>Lenton, T. M., Held, H., Kriegler, E., Hall, J. W., Lucht, W., Rahmstorf, S., & Schellnhuber, H. J. (2008). Tipping elements in the Earth's climate system. Proc Natl Acad Sci U S A, 105(6), 1786-1793. doi:10.1073/pnas.0705414105</p><p> </p><p><strong>Project website: http://uturndryland.wixsite.com/uturn</strong></p><p>This research is funded by the Belgian Federal Science Policy Office (Grant/Award Number:SR/00/339)</p>


2014 ◽  
Vol 7 (5) ◽  
pp. 2359-2391 ◽  
Author(s):  
E. D. Keller ◽  
W. T. Baisden ◽  
L. Timar ◽  
B. Mullan ◽  
A. Clark

Abstract. We adapt and integrate the Biome-BGC and Land Use in Rural New Zealand models to simulate pastoral agriculture and to make land-use change, intensification of agricultural activity and climate change scenario projections of New Zealand's pasture production at time slices centred on 2020, 2050 and 2100, with comparison to a present-day baseline. Biome-BGC model parameters are optimised for pasture production in both dairy and sheep/beef farm systems, representing a new application of the Biome-BGC model. Results show up to a 10% increase in New Zealand's national pasture production in 2020 under intensification and a 1–2% increase by 2050 from economic factors driving land-use change. Climate change scenarios using statistically downscaled global climate models (GCMs) from the IPCC Fourth Assessment Report also show national increases of 1–2% in 2050, with significant regional variations. Projected out to 2100, however, these scenarios are more sensitive to the type of pasture system and the severity of warming: dairy systems show an increase in production of 4% under mild change but a decline of 1% under a more extreme case, whereas sheep/beef production declines in both cases by 3 and 13%, respectively. Our results suggest that high-fertility systems such as dairying could be more resilient under future change, with dairy production increasing or only slightly declining in all of our scenarios. These are the first national-scale estimates using a model to evaluate the joint effects of climate change, CO2 fertilisation and N-cycle feedbacks on New Zealand's unique pastoral production systems that dominate the nation's agriculture and economy. Model results emphasise that CO2 fertilisation and N-cycle feedback effects are responsible for meaningful differences in agricultural systems. More broadly, we demonstrate that our model output enables analysis of decoupled land-use change scenarios: the Biome-BGC data products at a national or regional level can be re-sampled quickly and cost-effectively for specific land-use change scenarios and future projections.


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