Limits...
A Bayesian approach for temporally scaling climate for modeling ecological systems.

Post van der Burg M, Anteau MJ, McCauley LA, Wiltermuth MT - Ecol Evol (2016)

Bottom Line: Our results showed that wetland water surface areas tended to be larger in wetter conditions, but also changed less in response to climate fluctuations in the contemporary era.We also found that the average timescale parameter was greater in the historical period, compared with the contemporary period.Our results suggest that perhaps some interaction between climate and hydrologic response may be at work, and further analysis is needed to determine which has a stronger influence.

View Article: PubMed Central - PubMed

Affiliation: U.S. Geological Survey Northern Prairie Wildlife Research Center 8711 37th Street Jamestown North Dakota 58401.

ABSTRACT
With climate change becoming more of concern, many ecologists are including climate variables in their system and statistical models. The Standardized Precipitation Evapotranspiration Index (SPEI) is a drought index that has potential advantages in modeling ecological response variables, including a flexible computation of the index over different timescales. However, little development has been made in terms of the choice of timescale for SPEI. We developed a Bayesian modeling approach for estimating the timescale for SPEI and demonstrated its use in modeling wetland hydrologic dynamics in two different eras (i.e., historical [pre-1970] and contemporary [post-2003]). Our goal was to determine whether differences in climate between the two eras could explain changes in the amount of water in wetlands. Our results showed that wetland water surface areas tended to be larger in wetter conditions, but also changed less in response to climate fluctuations in the contemporary era. We also found that the average timescale parameter was greater in the historical period, compared with the contemporary period. We were not able to determine whether this shift in timescale was due to a change in the timing of wet-dry periods or whether it was due to changes in the way wetlands responded to climate. Our results suggest that perhaps some interaction between climate and hydrologic response may be at work, and further analysis is needed to determine which has a stronger influence. Despite this, we suggest that our modeling approach enabled us to estimate the relevant timescale for SPEI and make inferences from those estimates. Likewise, our approach provides a mechanism for using prior information with future data to assess whether these patterns may continue over time. We suggest that ecologists consider using temporally scalable climate indices in conjunction with Bayesian analysis for assessing the role of climate in ecological systems.

No MeSH data available.


Related in: MedlinePlus

Predicted water levels over time for a single wetland in North Dakota, U.S.A. The black line represents average predictions of the proportion of the basin covered with water assuming conditions prior to 1970 surrounded by 95% Bayesian credible intervals (gray). The red line represents average predictions assuming conditions after 2003 surrounded by 95% Bayesian credible intervals (pink). The predictions were made based on Standardized Precipitation Evapotranspiration Index values computed for each year assuming a distribution of possible values for timescale (see Fig. 3).
© Copyright Policy - creativeCommonsBy
Related In: Results  -  Collection

License
getmorefigures.php?uid=PMC4863021&req=5

ece32092-fig-0006: Predicted water levels over time for a single wetland in North Dakota, U.S.A. The black line represents average predictions of the proportion of the basin covered with water assuming conditions prior to 1970 surrounded by 95% Bayesian credible intervals (gray). The red line represents average predictions assuming conditions after 2003 surrounded by 95% Bayesian credible intervals (pink). The predictions were made based on Standardized Precipitation Evapotranspiration Index values computed for each year assuming a distribution of possible values for timescale (see Fig. 3).

Mentions: Using this same weighted climate index, we predicted the expected proportion of a basin to be covered with water using one of the wetlands from our sample as an example (Fig. 6). In general, the predicted patterns suggested that the amount of water covering a wetland historically tended to respond much more strongly to both dry and wet periods. Under more contemporary conditions, there were somewhat similar relative fluctuations in water surface area, but overall wetlands were much fuller, and responded over slightly shorter time periods compared with historical dynamics.


A Bayesian approach for temporally scaling climate for modeling ecological systems.

Post van der Burg M, Anteau MJ, McCauley LA, Wiltermuth MT - Ecol Evol (2016)

Predicted water levels over time for a single wetland in North Dakota, U.S.A. The black line represents average predictions of the proportion of the basin covered with water assuming conditions prior to 1970 surrounded by 95% Bayesian credible intervals (gray). The red line represents average predictions assuming conditions after 2003 surrounded by 95% Bayesian credible intervals (pink). The predictions were made based on Standardized Precipitation Evapotranspiration Index values computed for each year assuming a distribution of possible values for timescale (see Fig. 3).
© Copyright Policy - creativeCommonsBy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4863021&req=5

ece32092-fig-0006: Predicted water levels over time for a single wetland in North Dakota, U.S.A. The black line represents average predictions of the proportion of the basin covered with water assuming conditions prior to 1970 surrounded by 95% Bayesian credible intervals (gray). The red line represents average predictions assuming conditions after 2003 surrounded by 95% Bayesian credible intervals (pink). The predictions were made based on Standardized Precipitation Evapotranspiration Index values computed for each year assuming a distribution of possible values for timescale (see Fig. 3).
Mentions: Using this same weighted climate index, we predicted the expected proportion of a basin to be covered with water using one of the wetlands from our sample as an example (Fig. 6). In general, the predicted patterns suggested that the amount of water covering a wetland historically tended to respond much more strongly to both dry and wet periods. Under more contemporary conditions, there were somewhat similar relative fluctuations in water surface area, but overall wetlands were much fuller, and responded over slightly shorter time periods compared with historical dynamics.

Bottom Line: Our results showed that wetland water surface areas tended to be larger in wetter conditions, but also changed less in response to climate fluctuations in the contemporary era.We also found that the average timescale parameter was greater in the historical period, compared with the contemporary period.Our results suggest that perhaps some interaction between climate and hydrologic response may be at work, and further analysis is needed to determine which has a stronger influence.

View Article: PubMed Central - PubMed

Affiliation: U.S. Geological Survey Northern Prairie Wildlife Research Center 8711 37th Street Jamestown North Dakota 58401.

ABSTRACT
With climate change becoming more of concern, many ecologists are including climate variables in their system and statistical models. The Standardized Precipitation Evapotranspiration Index (SPEI) is a drought index that has potential advantages in modeling ecological response variables, including a flexible computation of the index over different timescales. However, little development has been made in terms of the choice of timescale for SPEI. We developed a Bayesian modeling approach for estimating the timescale for SPEI and demonstrated its use in modeling wetland hydrologic dynamics in two different eras (i.e., historical [pre-1970] and contemporary [post-2003]). Our goal was to determine whether differences in climate between the two eras could explain changes in the amount of water in wetlands. Our results showed that wetland water surface areas tended to be larger in wetter conditions, but also changed less in response to climate fluctuations in the contemporary era. We also found that the average timescale parameter was greater in the historical period, compared with the contemporary period. We were not able to determine whether this shift in timescale was due to a change in the timing of wet-dry periods or whether it was due to changes in the way wetlands responded to climate. Our results suggest that perhaps some interaction between climate and hydrologic response may be at work, and further analysis is needed to determine which has a stronger influence. Despite this, we suggest that our modeling approach enabled us to estimate the relevant timescale for SPEI and make inferences from those estimates. Likewise, our approach provides a mechanism for using prior information with future data to assess whether these patterns may continue over time. We suggest that ecologists consider using temporally scalable climate indices in conjunction with Bayesian analysis for assessing the role of climate in ecological systems.

No MeSH data available.


Related in: MedlinePlus