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Potential effects of climate change and fire management on fire behavior and vegetation patterns on an east Cascades landscapeGreaves, Heather E. 17 October 2012 (has links)
Climate exerts considerable control on wildfire regimes, and climate and wildfire are both major drivers of forest growth and succession in interior Northwest forests. Estimating potential response of these landscapes to anticipated changes in climate helps researchers and land managers understand and mitigate impacts of climate change on important ecological and economic resources. Spatially explicit, mechanistic computer simulation models are powerful tools that permit researchers to incorporate climate and disturbance events along with vegetation physiology and phenology to explore complex potential effects of climate change over wide spatial and temporal scales. In this thesis, I used the simulation model FireBGCv2 to characterize potential response of fire, vegetation, and landscape dynamics to a range of possible future climate and fire management scenarios. The simulation landscape (~43,000 hectares) is part of Deschutes National Forest, which is located at the interface of maritime and continental climates and is known for its beauty and ecological diversity. Simulation scenarios included all combinations of +0��C, +3��C, and +6��C of warming; +10%, ��0%, and -10% historical precipitation; and 10% and 90% fire suppression, and were run for 500 years. To characterize fire dynamics, I investigated how mean fire frequency, intensity, and fuel loadings changed over time in all scenarios, and how fire and tree mortality interacted over time. To explore vegetation and landscape dynamics, I described the distribution and spatial arrangement of vegetation types and forest successional stages on the landscape, and used a nonmetric multidimensional
scaling (NMS) ordination to holistically evaluate overall similarity of composition, structure, and landscape pattern among all simulation scenarios over time.
Changes in precipitation had little effect on fire characteristics or vegetation and landscape characteristics, indicating that simulated precipitation changes were not sufficient to significantly affect vegetation moisture stress or fire behavior on this landscape. Current heavy fuel loads controlled early fire dynamics, with high mean fire intensities occurring early in all simulations. Increases in fire frequency accompanied all temperature increases, leading to decreasing fuel loads and fire intensities over time in warming scenarios. With no increase in temperature or in fire frequency, high fire intensities and heavier fuel loads were sustained. Over time, more fire associated with warming or less fire suppression increased the percentage of the landscape occupied by non-forest and fire-sensitive early seral forest successional stages, which tended to increase the percentage of fire area burning at high severity (in terms of tree mortality). This fire-vegetation relationship may reflect a return to a more historical range of conditions on this landscape.
Higher temperatures and fire frequency led to significant spatial migration of forest types across the landscape, with communities at the highest and lowest elevations particularly affected. Warming led to an upslope shift of warm mixed conifer and ponderosa pine (Pinus ponderosa) forests, severely contracting (under 3�� of warming) or eliminating (under 6�� of warming) area dominated by mountain hemlock (Tsuga mertensiana) and cool, wet conifer forest in the high western portion of the landscape. In lower elevations, warming and fire together contributed to significant expansion of open (<10% tree canopy cover) forest and grass- and shrubland. The compositional changes and spatial shifts simulated in the warming scenarios suggest that climate change is likely to significantly affect forests on this landscape. Warming and associated fire also tended to increase heterogeneity of forest structural stages and landscape pattern, resulting in a more diverse distribution of structural stages, especially in lower elevations, and a more divided landscape of smaller forest stands.
The NMS ordination emphasized the dissimilarity between the severe +6�� scenarios and the other two temperature scenarios. The +0�� and +3�� scenarios differed from each other in composition (mainly because cool forest was lost in the +3�� scenarios), but within a given level of fire suppression they remained remarkably similar in terms of overall composition, structure,
and landscape pattern, while the +6�� scenarios separated noticeably from them. Such decisive differences suggest that under the simulated ranges of precipitation and fire suppression, the interval between 3 and 6 degrees of warming on this landscape may capture an ecological threshold, or tipping point.
Additional simulation research that incorporates (for example) management actions, insects and pathogens, and a wider array of precipitation scenarios could help illuminate more clearly the possible range of future landscape conditions. Still, these results provide a glimpse of potential divergent outcomes on this important landscape under possible future climates, and suggest that these forests will undergo considerable changes from both historical and current conditions in response to higher temperatures expected in this area. Some changes may be inevitable with warming, such as the upslope shift of warm forest types, but careful planning for fire and fuels management might allow land managers to modulate fire behavior and steer vegetation dynamics toward the most desirable outcome possible. / Graduation date: 2013
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Linking Three Decades of International Conservation Funding with South America’s Major Deforestation AreasQin, Siyu 17 November 2023 (has links)
Internationale Geldgeber haben die Finanzierung für den Schutz tropischer Wälder erhöht, um der globalen Herausforderung von Klima, Biodiversität und Nachhaltigkeit zu begegnen. Allerdings fehlen subnationale Informationen darüber, wo und wie die Gelder verteilt werden, welche Faktoren die Finanzierung beeinflussen und wie sie mit der Dynamik der Wälder und geschützten Gebiete korrelieren. Diese Thesis beabsichtigt, diese Fragen zu beantworten, indem sie sich mit drei Jahrzehnten internationaler Naturschutzfinanzierung in den Hauptabholzungsgebieten Südamerikas auseinandersetzt. Mithilfe gemischter Methoden habe ich die Interessen der Geldgeber thematisch und geografisch kartiert, räumliche Determinanten der Mittelvergabe identifiziert und Schwankungen der Finanzierung über Standorte und Zeit hinweg mit der Dynamik der Waldbedeckung und geschützten Gebiete verknüpft. Die Ergebnisse zeigten, dass die internationale Naturschutzfinanzierung eine Mischung aus global relevanten Interessen und bilateralen Interessen darstellt, ermöglicht durch sozioökonomische und biophysikalische Verbindungen zwischen den spendenden und empfangenden Regionen. Trockenwaldökosysteme mit hoher Abholzungsrate waren besonders unterfinanziert und gefährdeten die Ökosysteme, Arten und die lokale Bevölkerung. Die Verknüpfung von Schutzgebieten und Finanzierung mit dem Konzept der Landnutzungsdynamik enthüllte weitere Nuancen und half, kontextspezifische Empfehlungen zu identifizieren. Diese Studie präsentierte die erste subnationale Analyse der internationalen Naturschutzfinanzierung auf kontinentaler Ebene, zeigte Übereinstimmungen und Diskrepanzen zwischen den zugeteilten Ressourcen und den Naturschutzbedürfnissen und beleuchtete die komplexe und dynamische Landschaft der Finanzierungsmöglichkeiten, mit der andere Akteure umgehen müssen. / International donors have increased funding for tropical forest conservation to address the global challenge of climate, biodiversity, and sustainability. However, subnational information on where and how funds are allocated, factors influencing funding, and its correlation with forest dynamics and protected areas is lacking. This thesis aims to answer these questions by delving into three decades of international conservation funding in South America’s major deforestation areas. Using mixed methods, I mapped donor interests thematically and geographically, identify spatial determinants of funding allocation, and link funding variations across locations and time with forest cover and protected areas dynamics. Results found that international conservation funding carried a mix of globally relevant interests and bilateral interests enabled by socio-economic and biophysical connections between the donating and receiving regions. Dry forest ecoregions with high deforestation rates have been particularly underfunded, threatening the ecosystems, species, and local people depending on them. Dedicated global biodiversity fund, raising attention to drier ecosystems, targeting highly threatened areas, and making funding more accessible to local actors for local conservation needs, may help address the gap. This study presented the first subnational level analysis of international conservation funding at the continental scale, revealed the matches and mismatches between the allocated resources and the conservation needs, and shed light on the complex and dynamic landscape of funding opportunities that other actors need to navigate in.
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