Impact of environmental variables on tundra vegetation onset of flowering explained by survival modelling
(2019) In Student thesis series INES NGEM01 20191Dept of Physical Geography and Ecosystem Science
- Abstract
- Timing of phenological events are highly related to climate and is one of the first signs of ecosystem responses to the climate change. Timing of flowering phenology is an important trait influencing the distribution and fitness of plants species. Tundra ecosystems are particularly important to study these effects due to short growing seasons, poor pollinator community and a particularly pronounced expected climate change. In this study proportional hazard models are used to explain the impact of environmental variables and experimental warming tundra plant species’ onset of flowering.
The results show that global radiation and precipitation are negatively linked to onset of flowering, whereas thawing degree days only showed some weak... (More) - Timing of phenological events are highly related to climate and is one of the first signs of ecosystem responses to the climate change. Timing of flowering phenology is an important trait influencing the distribution and fitness of plants species. Tundra ecosystems are particularly important to study these effects due to short growing seasons, poor pollinator community and a particularly pronounced expected climate change. In this study proportional hazard models are used to explain the impact of environmental variables and experimental warming tundra plant species’ onset of flowering.
The results show that global radiation and precipitation are negatively linked to onset of flowering, whereas thawing degree days only showed some weak relationship to flowering. The negative impact of both radiation and precipitation are addressed to cooling the soil surface temperature and indicate further that local air temperature is not sufficient for explaining changes in onset of flowering.
In concordance with earlier research higher TDD sum previous year show a negative effect on the timing following year. The effect was particularly large on the early flowering species. Responses to experimental warming were stronger among late flowering dwarf shrubs, although the effect on early flowering species may have been out competed by snow melt dates. The study further suggests that survival modelling can be successfully used in phenology research providing accurate predictions of onset of flowering. Further studies of how the model application perform beyond the study area still needs to be tested. (Less) - Popular Abstract
- Plant phenology is the study of the seasonal timing of reoccurring plant events such as flowering, leaf bud burst and senescence and how it is affected by environmental factors or by other organisms. Timing of flowering is highly related to climate and influences the distribution and fitness of plants species. Tundra ecosystems are particularly important to study the effect of environmental changes due to the short growing seasons, relatively poor pollinator community as well as a particularly pronounced expected climate change. In this study a non-traditional method, survival modelling, was used to explain the impact of environmental variables and experimental warming tundra plant species on the onset of flowering.
The results show that... (More) - Plant phenology is the study of the seasonal timing of reoccurring plant events such as flowering, leaf bud burst and senescence and how it is affected by environmental factors or by other organisms. Timing of flowering is highly related to climate and influences the distribution and fitness of plants species. Tundra ecosystems are particularly important to study the effect of environmental changes due to the short growing seasons, relatively poor pollinator community as well as a particularly pronounced expected climate change. In this study a non-traditional method, survival modelling, was used to explain the impact of environmental variables and experimental warming tundra plant species on the onset of flowering.
The results show that global radiation and precipitation are negatively linked to onset of flowering. Whereas thawing degree days, the degree sum above 0°C and which has shown to impact flower timing in previous studies, only showed some weak positive relationship to flowering. The negative impact of both radiation and precipitation can be linked to a cooling effect of the soil surface temperature. Therefore, temperature still seems to be important which further would suggest that the temperature measurements used in this study does not capture the micro climatic effect of temperature on the onset of flowering.
The response to experimental warming was found for the late flowering dwarf shrubs having an advancing effect on flowering dates. This effect was not found for early flowering species but could have been out competed by snow melt dates. In concordance with earlier research higher thawing degree days from previous growing season showed a negative effect on the timing following year. The effect was particularly large on the early flowering species and could be explained by a bud set already in autumn.
The relationship between radiation and precipitation to plant phenology needs to be further assessed, both to understand the impact of these environmental variables and to make sure the impact is valid also for future predictions. Additionally, the effects of temperature and snow melt dates influence on flowering times needs to be investigated. This study does, however, suggest that survival modelling can be successfully used in phenology research providing accurate predictions of onset of flowering. Further studies of how the model application perform beyond the study area still needs to be tested. (Less)
Please use this url to cite or link to this publication:
http://lup.lub.lu.se/student-papers/record/8985377
- author
- Jonsson, Hanna LU
- supervisor
- organization
- course
- NGEM01 20191
- year
- 2019
- type
- H2 - Master's Degree (Two Years)
- subject
- keywords
- Flowering, Phenology, Cox proportional hazard model, Tundra, International tundra experiment, Climate change, Physical Geography and Ecosystem analysis
- publication/series
- Student thesis series INES
- report number
- 484
- language
- English
- additional info
- External supervisors: Robert Björk and Mats Björkman, Gothenburg university
- id
- 8985377
- date added to LUP
- 2019-06-18 15:46:36
- date last changed
- 2019-06-18 16:16:08
@misc{8985377,
abstract = {{Timing of phenological events are highly related to climate and is one of the first signs of ecosystem responses to the climate change. Timing of flowering phenology is an important trait influencing the distribution and fitness of plants species. Tundra ecosystems are particularly important to study these effects due to short growing seasons, poor pollinator community and a particularly pronounced expected climate change. In this study proportional hazard models are used to explain the impact of environmental variables and experimental warming tundra plant species’ onset of flowering.
The results show that global radiation and precipitation are negatively linked to onset of flowering, whereas thawing degree days only showed some weak relationship to flowering. The negative impact of both radiation and precipitation are addressed to cooling the soil surface temperature and indicate further that local air temperature is not sufficient for explaining changes in onset of flowering.
In concordance with earlier research higher TDD sum previous year show a negative effect on the timing following year. The effect was particularly large on the early flowering species. Responses to experimental warming were stronger among late flowering dwarf shrubs, although the effect on early flowering species may have been out competed by snow melt dates. The study further suggests that survival modelling can be successfully used in phenology research providing accurate predictions of onset of flowering. Further studies of how the model application perform beyond the study area still needs to be tested.}},
author = {{Jonsson, Hanna}},
language = {{eng}},
note = {{Student Paper}},
series = {{Student thesis series INES}},
title = {{Impact of environmental variables on tundra vegetation onset of flowering explained by survival modelling}},
year = {{2019}},
}