Mapping, hydrologic modeling and connectivity of depressional wetlands in central Oklahoma

The objectives of this study were to (1) develop a method to improve map quality for temporarily inundated depressional wetlands in central Oklahoma, (2) create a predictive hydrologic model for those wetlands, and (3) assess the spatiotemporal variability in landscape connectivity on invertebrate communities.(1) Accurate wetland maps are an important resource for wetland management with applications including prioritizing restoration and tracking habitat loss. Traditional wetland maps utilize single-date imagery often underestimating ephemeral wetlands. High-recurrence satellite imagery was classified to identify patterns of inundation in regional wetlands over an 18 year period with high accuracy. Updated maps identified over 700 more wetlands than maps previously available for the area. Because new maps were created using long-term inundation information, they also included more accurate water regime attributes.(2) Classified satellite images were also used to develop regional wetland hydrologic models. Inundation in approximately 500 wetlands was modeled over 18 years using climate data, land-use and wetland size as independent variables. The quantity, intensity and timing of rainfall as well as long-term drought indices were all important in predicting wetland inundation. Furthermore, small wetlands in grassland watersheds were less likely to be inundated than large wetlands surrounded by agriculture. Under future climate scenarios, regional wetlands are potentially at risk of decreased frequency of inundation, with small grassland wetlands most vulnerable.(3) Landscape connectivity of inundated wetlands also impacts biotic communities. This study provides evidence for temporally variable effects of connectivity and vegetation complexity on wetland invertebrate richness and metacommunity organization. Late in the growing season vegetation complexity had a greater effect on richness and sites with similar vegetation increased in community similarity. Permanent wetlands appear to act as refuges during periods of drought and supply colonists to temporary wetlands early in the growing season. Early in the season dispersal increases wetland richness and makes proximate sites more compositionally similar. Late in the season, the spatial scale at which wetlands are connected appears to depend on the number of inundated wetlands regionally. Understanding the temporal fluctuations in local and regional effects is likely to elucidate the complex patterns of wetland invertebrate community organization

Influence of Environmental Stress and Anthropogenic Disturbance on the Energy Expenditure of Wintering Northern Pintails (Anas acuta)

Winter conditions impose hardships on waterfowl, impacting how they apportion energy and time. Human disturbances may affect this energetic balance, influence lipid reserves, and potentially survival. Objectives of this study were to determine effects of environmental and anthropogenic factors on energetic expenditure (kcal/day) of Northern Pintails (Anas acuta) in behaviors commonly associated with a disturbance response (alert, locomotion, and flight) during winter 2008-2009 and 2009-2010 at Bosque del Apache National Wildlife Refuge in central New Mexico, USA. The refuge is a frequently visited ecotourism destination with over 170,000 visitors each winter. Thermoregulatory cost, time-of-winter, amount of natural and anthropogenic disturbances, and forage availability were examined to determine their influence on pintail energetic response (e.g., flight, locomotion, alert behavior). Average number of pintails ranged from 7,524-15,769. Using Akaike Information Criteria, the top-ranked model indicated that increased thermoregulatory cost, and by association decreased temperature, may cause a decline in energetic response of pintails to disturbances. Modeled values for energetic response had a mean (± SE) of 175 ± 11.5 kcal/day in year 1, and 111.7 ± 7.22 kcal/day in year 2. Neither the amount of disturbance nor forage availability strongly influenced energetic response. Results of this study raise questions about the efficacy of using behavior or energy expenditure data, alone, to assess anthropogenic disturbance effects on waterfowl

Influence of Environmental Stress and Anthropogenic Disturbance on the Energy Expenditure of Wintering Northern Pintails (Anas acuta)

Winter conditions impose hardships on waterfowl, impacting how they apportion energy and time. Human disturbances may affect this energetic balance, influence lipid reserves, and potentially survival. Objectives of this study were to determine effects of environmental and anthropogenic factors on energetic expenditure (kcal/day) of Northern Pintails (Anas acuta) in behaviors commonly associated with a disturbance response (alert, locomotion, and flight) during winter 2008-2009 and 2009-2010 at Bosque del Apache National Wildlife Refuge in central New Mexico, USA. The refuge is a frequently visited ecotourism destination with over 170,000 visitors each winter. Thermoregulatory cost, time-of-winter, amount of natural and anthropogenic disturbances, and forage availability were examined to determine their influence on pintail energetic response (e.g., flight, locomotion, alert behavior). Average number of pintails ranged from 7,524-15,769. Using Akaike Information Criteria, the top-ranked model indicated that increased thermoregulatory cost, and by association decreased temperature, may cause a decline in energetic response of pintails to disturbances. Modeled values for energetic response had a mean (± SE) of 175 ± 11.5 kcal/day in year 1, and 111.7 ± 7.22 kcal/day in year 2. Neither the amount of disturbance nor forage availability strongly influenced energetic response. Results of this study raise questions about the efficacy of using behavior or energy expenditure data, alone, to assess anthropogenic disturbance effects on waterfowl

Assessing natural and anthropogenic variability in wetland structure for two hydrogeomorphic riverine wetland subclasses

The hydrogeomorphic approach (HGM) to wetland classification and functional assessment has been applied regionally throughout the United States, but the ability of HGM functional assessment models to reflect wetland condition has limited verification. Our objective was to determine how variability derived from anthropogenic effects and natural variability impacted site assessment variables within regional wetland subclasses in central Oklahoma. We collected data for nine potential assessment variables including vegetation physiognomy (e.g., tree basal area, herbaceous cover, canopy cover, etc.) and soil organic matter at wetlands of two HGM riverine subclasses (oxbow and riparian) in May and June, 2010. Using Akaike Information Criteria, we identified limited relationships between landscape disturbance metrics and assessment variables within subclasses. The high degree of natural variability from climatic and hydrologic factors within both subclasses may be masking the impact of landscape disturbance on the other measured assessment variables. Precipitation had significant effects on assessment variables within each of the subclasses. To reduce natural climatic variability, the reference domain may need to be further subdivided. The approach used in this study provides fairly rapid and quantitative methods for evaluating the effectiveness of using HGM assessment variables in assessing wetland condition regionally