Ecological correlates of trophic polyphenism in spadefoot tadpoles inhabiting playas

2009 ◽  
Vol 87 (3) ◽  
pp. 229-238 ◽  
Author(s):  
D. M. Ghioca-Robrecht ◽  
L. M. Smith ◽  
L. D. Densmore
Keyword(s):  
Land Use ◽  
Water Depth ◽  
Water Loss ◽  
Larval Amphibians ◽  
Spadefoot Toads ◽  
Amphibian Community ◽  
Grassland Type ◽  
Shrimp Density ◽  
Spea Bombifrons ◽  
Wetland Hydroperiod

Polyphenism in larval amphibians has been related to several factors, including wetland hydroperiod, food availability, competition, and predation. Spadefoot toads (genus Spea Cope, 1866) often exhibit a trophic polyphenism by developing distinct carnivore and omnivore larval morphotypes. Using a multimodel selection approach, we investigated the influence of land use (cropland vs. grassland type) and differences in annual precipitation on morphotype expression in Plains spadefoot ( Spea bombifrons (Cope, 1863)) and New Mexico spadefoot ( Spea multiplicata (Cope, 1863)) toads in playas. We also examined the relative importance of tadpole density, tadpole age, water-loss stress, wetland size, density of larval mole salamanders (genus Ambystoma Tschudi, 1838; a predator on Spea tadpoles), and food resources on morph occurrence. The carnivore morphotype developed almost exclusively in S. bombifrons and rarely in S. multiplicata regardless of land use. Habitat availability measured by water-loss rate, as well as predation risk and tadpole age, were the most important factors influencing carnivore proportions. Ambystoma density was positively associated, whereas water-depth loss and tadpole age were negatively associated with the proportion of carnivores. The greatest proportion of carnivores was observed in grassland playas, which had the highest density of Ambystoma predators, longest hydroperiods, and experienced water-depth gain. Fairy shrimp density was not correlated with the proportion of carnivores. Upland land use through cultivation-associated erosion is altering wetland trophic structure, which further influences morphotype expression in Spea tadpoles and playa amphibian community structure.

scholarly journals The MODIS Global Vegetation Fractional Cover Product 2001–2018: Characteristics of Vegetation Fractional Cover in Grasslands and Savanna Woodlands

2020 ◽  
Vol 12 (3) ◽  
pp. 406 ◽  
Author(s):  
Michael J. Hill ◽  
Juan P. Guerschman
Keyword(s):  
Land Use ◽  
Production Systems ◽  
Land Use Changes ◽  
Bare Soil ◽  
Additional Information ◽  
Fractional Cover ◽  
Grassland Type ◽  
Global Vegetation ◽  
Global Indicator

Vegetation Fractional Cover (VFC) is an important global indicator of land cover change, land use practice and landscape, and ecosystem function. In this study, we present the Global Vegetation Fractional Cover Product (GVFCP) and explore the levels and trends in VFC across World Grassland Type (WGT) Ecoregions considering variation associated with Global Livestock Production Systems (GLPS). Long-term average levels and trends in fractional cover of photosynthetic vegetation (FPV), non-photosynthetic vegetation (FNPV), and bare soil (FBS) are mapped, and variation among GLPS types within WGT Divisions and Ecoregions is explored. Analysis also focused on the savanna-woodland WGT Formations. Many WGT Divisions showed wide variation in long-term average VFC and trends in VFC across GLPS types. Results showed large areas of many ecoregions experiencing significant positive and negative trends in VFC. East Africa, Patagonia, and the Mitchell Grasslands of Australia exhibited large areas of negative trends in FNPV and positive trends FBS. These trends may reflect interactions between extended drought, heavy livestock utilization, expanded agriculture, and other land use changes. Compared to previous studies, explicit measurement of FNPV revealed interesting additional information about vegetation cover and trends in many ecoregions. The Australian and Global products are available via the GEOGLAM RAPP (Group on Earth Observations Global Agricultural Monitoring Rangeland and Pasture Productivity) website, and the scientific community is encouraged to utilize the data and contribute to improved validation.

Adjacent land-use affects amphibian community composition and species richness in managed forests in New Brunswick, Canada

2011 ◽  
Vol 41 (8) ◽  
pp. 1687-1697 ◽  
Author(s):  
Lee Jacobs ◽  
Jeff E. Houlahan
Keyword(s):  
Land Use ◽  
Species Richness ◽  
New Brunswick ◽  
Community Composition ◽  
Managed Forests ◽  
Road Density ◽  
Amphibian Species ◽  
Precommercial Thinning ◽  
Amphibian Community ◽  
Land Use Effects

Here, we examine the effects of adjacent land use in a managed forest on pond-breeding amphibian species richness and community composition at 34 New Brunswick, Canada, ponds. Amphibian species richness was negatively correlated with the proportion of roads, precommercial thinning, and hardwood forest and positively correlated with the proportion of wetlands in adjacent lands. These land-use effects peak at 180 m from the ponds. Road density was negatively correlated with Lithobates catesbeiana and Lithobates septentrionalis presence. Precommercial thinning was negatively correlated with Ambystoma spp. presence and positively correlated with Anaxyrus americanus presence. Wetlands were positively correlated with L. septentrionalis and Notopthalamus viridescens presence. Correlations were also found between water table height and A. americanus, Lithobates palustris , and Ambystoma spp. presence. In addition, L. catesbeiana and N. viridescens presence–absence was positively correlated with the proportion of mature and overmature forest on the landscape (at scales of 500 and 1000 m, respectively). Lastly, the proportion of regenerating and sapling forest on the landscape was negatively correlated with L. palustris presence–absence but, by contrast, was positively correlated with A. americanus. These results suggest that the effects of adjacent land use may significantly impact amphibian populations in managed eastern Canadian forests.

The role of Spadefoot Toad tadpoles in wetland trophic structure as influenced by environmental and morphological factors

2011 ◽  
Vol 89 (1) ◽  
pp. 47-59 ◽  
Author(s):  
D. M. Ghioca-Robrecht ◽  
L. M. Smith
Keyword(s):  
Body Size ◽  
Great Plains ◽  
Trophic Structure ◽  
Trophic Levels ◽  
Wetland Ecosystems ◽  
Southern Great Plains ◽  
Larval Amphibians ◽  
Spadefoot Toad ◽  
Spea Bombifrons ◽  
And Function

Larval amphibians reach high densities in playa wetlands in the Southern Great Plains (SGP), USA, and thus may influence the entire structure and function of these ecosystems. We investigated whether both carnivorous and omnivorous morphotypes of Spadefoot Toad tadpoles (New Mexico Spadefoot, Spea multiplicata (Cope, 1863), and Plains Spadefoot, Spea bombifrons (Cope, 1863)) would exhibit a macrophagous feeding behavior that would allow them to occupy several trophic levels in playas. We also compared tadpole diets and foregut widths as influenced by the land use surrounding playas (cultivated versus grassland watersheds), year (dry versus wet year), and body size (snout-to-vent length). Tadpole diets were dominated by detritus and diatoms and tadpole foreguts increased with body size. Generally, more arthropods and less cyanobacteria were found in Spea tadpole diets as tadpoles grew larger, suggesting they influence different trophic levels with age. Foreguts were wider in carnivores than omnivores, suggesting carnivores had increased ability to ingest larger prey. Also, omnivores had wider foreguts in cropland than grassland playas, suggesting they ingest larger food items in cropland playas. From estimates of the amounts of invertebrates, detritus, and algae consumed by Spea tadpoles, we demonstrate that these larvae influence the entire trophic structure of wetland ecosystems.

scholarly journals Quantification of Stream Drying Phenomena Using Grid-Based Hydrological Modeling via Long-Term Data Mining throughout South Korea including Ungauged Areas

Water ◽  
2019 ◽  
Vol 11 (3) ◽  
pp. 477 ◽  
Author(s):  
Chunggil Jung ◽  
Jiwan Lee ◽  
Yonggwan Lee ◽  
Seongjoon Kim
Keyword(s):  
Land Use ◽  
Water Loss ◽  
Road Network ◽  
Hydrological Modeling ◽  
Assessment Tool ◽  
Soil Depth ◽  
Minimum Flow ◽  
Stream Drying ◽  
Total Runoff ◽  
Weather Changes

The Drying Stream Assessment Tool and Water Flow Tracking (DrySAT-WFT) were modified to simulate the hydrological components of water loss databases (DBs) affecting stream drying phenomena. In this study, the phenomenon is defined based on a method using the 10-day minimum flow (reference Q355). Prior to identifying the method using reference Q355, the DrySAT-WFT model was calibrated and verified for its performance with the total runoff (TQ), evapotranspiration (ET), and soil moisture (SM) at 12 streamflow locations, 3 ET locations, and 58 SM locations. The average R2 for TQ in 2005 to 2015 were 0.66 to 0.84, which demonstrates good performance. Moreover, Nash Sutcliffe model efficiency (NSE) values were 0.52 to 0.72, which are also good. After verifying the DrySAT-WFT model for hydrologic components, in order to apply the method, this study defined the drying progress which was analyzed by the stream drying index (SDI) as decision criteria. In this study, the criteria for the estimation of SDI were calculated as reference Q355 coming from the 10-day minimum flow considering only weather changes from 1976 to 2015. Then, SDI grades were determined by counting the number of days below a reference Q355 from TQ considering all water loss databases (DBs) such as weather changes, groundwater uses, forest heights, soil depths, land use, and road network. On the other hand, SDI represents how many days below the reference Q355 increased when all water loss DBs were applied, in comparison to when only weather changes were applied. The DrySAT-WFT model simulated the hydrological components of the water balance based on each water loss DB, including the application of all DBs. As a result, the change ratios for TQ were measured: −4.8% for groundwater use (GWU), −1.3% for forest height (FH), −0.3% for road network (RN), −0.1% for land use (LU) and −0.1% for soil depth (SD). Overall, TQ values decreased by -8.4%. The change ratios for ET were measured: −2.0% for GWU, +10.5% for FH, +5.6% for RN, −1.8% for LU and +0.3% for SD. Overall, the ET values increased by +14.7%. In addition, based on all water loss DBs, the SDI was evaluated for all watersheds, which intensified recently (2006–2015). Under weather DB conditions, the average SDI was measured as 2.0 for all watersheds. Stream drying processes remained limited, requiring only monitoring. Given baseline conditions, stream drying intensified to grades of 3.1 (1976–1985), 3.2 (1986–1995), 3.3 (1996–2005) and 3.5 (2006–2015) by all water loss DBs.

The relationship between wetland hydroperiod and nestedness patterns in assemblages of larval amphibians and predatory macroinvertebrates

Oikos ◽  
2004 ◽  
Vol 107 (1) ◽  
pp. 16-27 ◽  
Author(s):  
Matthew J. Baber ◽  
Erica Fleishman ◽  
Kimberly J. Babbitt ◽  
Tracy L. Tarr
Keyword(s):  
Larval Amphibians ◽  
Wetland Hydroperiod ◽  
The Relationship

Characteristics of Reference Evapotranspiration of Wetland Based on Penman-Monteith and Hargreaves Methods

2012 ◽  
Vol 610-613 ◽  
pp. 3013-3016
Author(s):  
Xiang Hu Li ◽  
Qi Zhang ◽  
Yun Liang Li
Keyword(s):  
Correlation Coefficient ◽  
Direct Measurement ◽  
Water Depth ◽  
Water Loss ◽  
Strong Correlation ◽  
Reference Evapotranspiration ◽  
Relative Importance ◽  
Monthly Means ◽  
Different Types ◽  
Hargreaves Equation

Evapotranspiration (ET) constitutes the dominant water loss from many different types of wetlands. The relative importance of ET is apparent in its influence over water depth, temperature and salinity. However, direct measurement of ET, especially for wetland, is difficult, costly, and rarely available. In this study, the Penman-Monteith model was selected to estimate the reference evapotranspiration for short and tall canopies, moreover, Hargreaves equation was also used to simulate the ETref and test the precision of Penman-Monteith method. The results show that the reference evapotranspiration are maximal between June and August and minimal in winter, and ETrs is larger than ETos in the whole simulation periods. H ET0 and ETos have the same variation trend, but the former was smaller than the latter during May to September. Finally, there is a strong correlation between ETos and ETrs, with the correlation coefficient are 0.98 and 0.99 at daily and monthly means scale.

The impact of land use on water loss and soil desiccation in the soil profile

2017 ◽  
Vol 26 (1) ◽  
pp. 185-196 ◽  
Author(s):  
Jing Zhang ◽  
Li Wang
Keyword(s):  
Land Use ◽  
Water Loss ◽  
Soil Profile ◽  
Soil Desiccation ◽  
The Impact

Vegetation and Land use Impact on Water Loss Rate in Playas of the Southern High Plains, USA

Wetlands ◽  
2010 ◽  
Vol 30 (6) ◽  
pp. 1107-1116 ◽  
Author(s):  
Jo-Szu Tsai ◽  
Louise S. Venne ◽  
Scott T. McMurry ◽  
Loren M. Smith
Keyword(s):  
Land Use ◽  
Water Loss ◽  
Loss Rate ◽  
High Plains ◽  
Southern High Plains ◽  
Water Loss Rate ◽  
Land Use Impact

Effects of surrounding land use and water depth on seagrass dynamics relative to a catastrophic algal bloom

2016 ◽  
Vol 31 (1) ◽  
pp. 67-75 ◽  
Author(s):  
David R. Breininger ◽  
Robert D. Breininger ◽  
Carlton R. Hall
Keyword(s):  
Land Use ◽  
Water Depth ◽  
Algal Bloom
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