scholarly journals Assessment of the Littoral Macrophyte Community in Jackson Lake, Grand Teton National Park,Wyoming

1990 ◽  
Vol 14 ◽  
pp. 79-82
Author(s):  
Carol Brewer
Keyword(s):  
Water Level ◽  
Plant Community ◽  
National Park ◽  
Aquatic Plant ◽  
Current Status ◽  
Grand Teton National Park ◽  
Bureau Of Reclamation ◽  
Littoral Habitat ◽  
Macrophyte Community ◽  
The Status

Beginning in 1978, the water level of Jackson Lake, Grand Teton National Park, Wyoming, was lowered first from 2064.5 m (normal pool) to somewhere between 2060-2061 m, and then in 1985 to 2057 m. The purpose of these drawdowns was to facilitate repair and modification of the Jackson Lake dam. In 1989, repair was completed and the reservoir was allowed to fill back to the normal pool elevation of 2065 m. Because of impacts to the littoral habitat in Jackson Lake caused by restoration of the dam at the Snake River outlet, the status of the aquatic plant community was assessed in August, 1989 and 1990. Previous investigations conducted in 1983 (prior to reconstruction) and 1985 (immediately following drawdown to 2055 m) served as a baseline for comparisons. this report summarizes findings from the 1989 and 1990 studies on impacts to the littoral macrophyte community caused by the repair-related drawdowns. To evaluate the current status of the plant community in Jackson Lake, the following objectives were addressed during August, 1990: 1. Re-examine sites sampled in 1989; 2. Examine sites planted during the summers of 1989 and 1990 by the Bureau of Reclamation.

scholarly journals Assesment of the Littoral Macrophyte Community in Jackson Lake, Grand Teton National Park, Wyoming Following Reconstruction of the Jackson Lake Dam

1989 ◽  
Vol 13 ◽  
pp. 90-95
Author(s):  
Carol Brewer
Keyword(s):  
Plant Community ◽  
National Park ◽  
Aquatic Plant ◽  
Detailed Report ◽  
Grand Teton National Park ◽  
Littoral Habitat ◽  
Macrophyte Community ◽  
The Status ◽  
The U.S

Beginning in 1978, the water level of Jackson Lake, Grand Teton National Park, Wyoming, was lowered first from 2064.5m (normal pool) to between 2060.3m-2061.8m, and then in 1985 to 2057.2m. The purpose of these drawdowns was to facilitate repair and modification of the Jackson Lake dam. In 1989, repair was completed and the reservoir was allowed to fill back to the normal pool elevation of 2064.5m Because of impacts to the littoral habitat in Jackson Lake caused by restoration of the dam at the Snake River outlet, the status of the aquatic plant community was assessed in August, 1989, to follow up to investigations conducted in 1983 (prior to reconstruction) and 1985 (immediately following drawdown to 2055.4m) by Brewer (1986). This report summarizes findings from the 1989 study on impacts to the littoral macrophyte community caused by the repair-related drawdowns. A detailed report assessing current physical and biological conditions in Jackson Lake was submitted to the U.S. Fish and Wildlife Service in October (Brewer, 1989).

scholarly journals Assessment of the Aquatic Plant Community in Jackson Lake, Grand Teton National Park, Wyoming: 1991 Status Report

1991 ◽  
Vol 15 ◽  
pp. 139-143
Author(s):  
Carol Brewer
Keyword(s):  
Water Level ◽  
Plant Community ◽  
Aquatic Plant ◽  
Water Levels ◽  
Water Level Fluctuations ◽  
Status Report ◽  
Littoral Habitat ◽  
Macrophyte Community ◽  
The Status ◽  
Annual Changes

Since the construction of the first dam at the Snake River outlet at Jackson Lake in the early 1900's, the littoral habitat has been subjected to numerous perturbations of varying intensities. Changing water levels, a consequence of reservoir drawdown schedules, alter plant community species composition and distribution over time. From the perspective of a plant, water level changes present a challenge to growth and community persistence. A plant which begins the growing season 2 m deep may be under 4 m of water after spring runoff fills the reservoir. Later in the summer, the same plant may be left at a depth of only 1 m as water is removed from the reservoir during summer drawdown. The magnitude and timing of water level fluctuations may be one of the most important factors regulating macrophyte community processes upslope on the vertical gradient in Jackson Lake (Brewer and Parker 1990). Under normal regulation, annual changes of 3-4 m are sufficient to select for a plant community with a typically weedy phenology (e.g., Elodea canadensis). In natural lakes with substantially lower annual changes in water levels, species that produce seeds annually are favored (e.g., Potamogeton species). Moreover, drawdowns greater than several meters substantially reduce the lake bed area suitable for the development of extensive shallow water plant beds. The most recent perturbations to the littoral habitat in Jackson Lake began in 1978, when the water level was lowered first from 2065 m (normal pool) to somewhere between 2060 - 2062 m. Then in 1985, the surface elevation of Jackson Lake was further lowered to 2057 m to facilitate repair and modification of the Jackson Lake dam. The entire lake bed was seriously impacted during the four years that the dam was being restored. While the lake bed in the borrow zone and the area adjacent to the dam were obviously impacted by repair activities, the entire shallow littoral zone was severely perturbed when previously inundated sediments were exposed for four years. In 1989, repair was completed and the reservoir was allowed to fill back to the normal pool elevation of 2065 m. Because of severe impacts to the littoral habitat and significant reduction of the submergent plant community caused by restoration of the dam, the status of the aquatic plant community was monitored during the summers of 1989-1991. This report summarizes the status of the aquatic plant community three years after repair of the dam was completed.

scholarly journals Seed Bank Viability in Jackson Lake Grand Teton National Park, Wyoming

1996 ◽  
Vol 20 ◽  
pp. 31-34
Author(s):  
Carol Brewer ◽  
Melissa Brown
Keyword(s):  
Plant Community ◽  
Seed Bank ◽  
National Park ◽  
Aquatic Plant ◽  
Water Levels ◽  
Water Level Fluctuations ◽  
Disturbance Regime ◽  
Grand Teton National Park ◽  
Macrophyte Community ◽  
Macrophyte Growth

The submersed plant community in Jackson Lake is an important resource in Grand Teton National Park for both terrestrial and aquatic organisms. Since the early 1900's, Jackson Lake has been influenced by a series of drawdowns of varying magnitude that influenced the composition and extent of the macrophyte community in the littoral zone. While many physical conditions have been linked to macrophyte growth and distribution in lakes (e.g., light, sediments, nutrients, slope) recent work suggests that the magnitude and timing of water level fluctuations may be the most important factor regulating macrophyte community processes at shallower depths in regulated reservoirs (Brewer and Parker 1990; Gasith and Gafny 1990; Rerslett 1984, 1987). Because of the importance of the aquatic plant community in Jackson Lake as a food source and shelter for wildlife (waterfowl, fish,invertebrates, mammals), the factors affecting growth and recovery after disturbance have received periodic attention since the late 1960's (Hayden 1969; Brewer 1986; Brewer and Rerslett 1987; Brewer and Parker 1990; Brewer and Thompson 1994). Initial work on plant community dynamics in Jackson Lake has shown that the aquatic plant community in Jackson Lake has been exposed to a varied disturbance regime that has impacted recolonization, species diversity and peak biomass development. Because the extent of littoral habitat suitable for macrophyte growth in regulated lakes depends on the timing and magnitude of seasonal and long-term drawdowns, drawdown schedules and resulting fluctuating water levels may be selecting for a plant community characterized by low diversity and patchy distribution. Peak production under such conditions in Jackson Lake tends to be shifted into deeper waters (Brewer and Parker 1990; Brewer and Thompson 1994). Furthermore, clonal, weedy species with reduced value for wildlife (e.g., Elodea canadensis, Myriophyllum sibericum) have enhanced opportunities for dispersal under such a disturbance regime and are favored when maximum drawdown occurs during the period of peak standing crop. While historical records describing changing patterns of macrophyte distribution are available for Jackson Lake, few data are available to evaluate the influence of fluctuating water levels on the seed bed, and the potential for recruitment after disturbance from this source. The objective for our work was to establish protocols and collect preliminary data on the potential for recruiting macrophytes from the littoral seed bank by measuring germination of seeds from lake sediments.

scholarly journals Distribution of Littoral Macrophytes in Jackson Lake, Wyoming

1983 ◽  
Vol 7 ◽  
pp. 73-76
Author(s):  
C. Brewer ◽  
M. Parker
Keyword(s):  
Plant Species ◽  
National Park ◽  
Structure And Function ◽  
Distribution Data ◽  
Grand Teton National Park ◽  
Littoral Habitat ◽  
Macrophyte Community ◽  
Field Season ◽  
Relative Abundances ◽  
And Function

The research described here is part of a 2-year study to characterize the structure and function of the littoral macrophyte community in Jackson Lake, Grand Teton National Park. The objectives for the 1st year were: 1) to identify the plant species occuring in the lake; 2) to quantify their relative abundances; 3) to characterize the littoral habitat, and; 4) to construct a detailed map of macrophyte distribution. Data collected during the first field season will be used to help evaluate results of experiments conducted during year two on mechanisms affecting macrophyte segregation.

scholarly journals The Submersed Aquatic Plant Community in Jackson Lake, Grand Teton National Park, Wyoming

1995 ◽  
Vol 19 ◽  
pp. 14-18
Author(s):  
Carol Brewer
Keyword(s):  
Water Level ◽  
Plant Community ◽  
Aquatic Plant ◽  
Nutrient Status ◽  
Growing Season ◽  
Water Levels ◽  
Water Level Fluctuations ◽  
Species List ◽  
Spring Runoff ◽  
Macrophyte Community

Submergent macrophyte distribution in lakes is usually related to depth. At lower depths (downslope on the littoral lake bed), macrophyte distribution and growth have been related to light (Spence 1982), substrate texture, nutrient status (Carpenter and Adams 1977), and lake morphometry (Duarte and Kalff 1986). Factors limiting distribution and growth at shallower depths (upslope on the littoral shore) are not as well understood. Meaningful descriptions of plant distributions in reservoirs are problematic because water levels vary through the course of a year (Brewer and Rerslett 1987). Water level fluctuations are a challenge to plant growth. A plant which begins the growing season at a depth of 3 m may be under 6 m of water after spring runoff fills the reservoir. Later in the summer, the same plant may be left at a depth of only 1 m as water is removed from the reservoir during summer drawdown. In reservoirs, where lake levels fluctuate substantially durin_g the growing season, the physical environment is characterized by increased spatial and temporal heterogeneity. Disturbances associated with changing water levels include ice scour during winter drawdown, abrasion due to increased erosion along the lake shore and wave action. Recent work suggests that the magnitude and timing of water level fluctuations may be the most important factor regulating macrophyte community processes at shallower depths in reservoirs (Gasith and Gafny 1990; Brewer and Parker 1990; Rorslett 1984). The status of the aquatic plant community in Jackson Lake was re-evaluated from June - August, 1995. During this time, we compiled a species list and mapped the distribution of macrophyte species.

scholarly journals Effects of Domestic Livestock and Native Wildlife Grazing in Grand Teton National Park

1993 ◽  
Vol 17 ◽  
pp. 91-95
Author(s):  
Michael Smith ◽  
Jerrold Dodd ◽  
Paul Meiman
Keyword(s):  
Plant Community ◽  
National Park ◽  
Mule Deer ◽  
Snake River ◽  
Grand Teton National Park ◽  
Jackson Hole ◽  
Domestic Livestock ◽  
Wildlife Populations

The Snake River plains and foothill areas of Jackson Hole have been grazed by domestic livestock since settlement of the area. Wildlife populations, including elk, mule deer, and antelope have historically used and continue to use the area. Moose are currently relatively abundant and a small herd of bison have been introduced. Currently, livestock use part of the area contained in Grand Teton National Park either as a concession or due to authorization by Park enabling legislation. Park managers need information concerning the effects of grazing by large ungulates on vegetation resources to assist in effectively managing grazing to service forage needs and achieve desired plant community goals.

scholarly journals The wild dog—Africa's vanishing carnivore

Oryx ◽  
1991 ◽  
Vol 25 (3) ◽  
pp. 137-146 ◽  
Author(s):  
John H. Fanshawe ◽  
Lory H. Frame ◽  
Joshua R. Ginsberg
Keyword(s):  
National Park ◽  
Sub Saharan Africa ◽  
Current Status ◽  
Lycaon Pictus ◽  
Term Survival ◽  
African Wild Dog ◽  
The Status ◽  
Sub Saharan ◽  
Wild Dog

This paper presents a synopsis of the current status and distribution of the African wild dog Lycaon pictus, outlines reasons for its decline and discusses recommendations to halt or reverse this decline. A recent review of the status of the species provides evidence that it has disappeared or is in decline throughout its range (sub-Saharan Africa). Relict populations with little or no chance of long-term survival are found in several countries including Algeria and Senegal. Countries believed to contain potentially viable populations are, from north to south, Kenya, Tanzania, Zambia, Zimbabwe, Botswana, and South Africa (only the Kruger National Park).

scholarly journals Factors Controlling Macrophyte Breakage in Jackson Lake, Grand Teton National Park, Wyoming

1984 ◽  
Vol 8 ◽  
pp. 63-68
Author(s):  
Michael Parker ◽  
Carol Brewer ◽  
Thomas Thompson
Keyword(s):  
Littoral Zone ◽  
National Park ◽  
Water Movement ◽  
Structure And Function ◽  
Main Axis ◽  
Grand Teton National Park ◽  
Macrophyte Community ◽  
Second Year ◽  
The Absolute ◽  
And Function

The research described here is part of a two year study to characterize the structure and function of the littoral macrophyte community in Jackson Lake, Wyoming. The objectives for the second year were to perform experiments to: 1) Index water movement in the littoral zone of the lake; 2) Identify the zones where the greatest plant breakage occured; 3) Determine the mechanisms and the absolute force required to break the main axis of a plant, and; 4) Measure the productivity of several species of macrophytes.

scholarly journals Distribution and status of living colonies of Acropora spp. in the reef crests of a protected marine area of the Caribbean (Jardines de la Reina National Park, Cuba)

PeerJ ◽  
2019 ◽  
Vol 7 ◽  
pp. e6470 ◽  
Author(s):  
Leslie Hernández-Fernández ◽  
Roberto González de Zayas ◽  
Yunier M. Olivera ◽  
Fabián Pina Amargós ◽  
Claudia Bustamante López ◽  
...  
Keyword(s):  
National Park ◽  
Negative Relationship ◽  
Current Status ◽  
Maximum Diameter ◽  
Future Research ◽  
Acropora Palmata ◽  
Direct Observations ◽  
Marine Park ◽  
The Status ◽  
Conservation Actions

The reef crests of the Jardines de la Reina National Park (JRNP) are largely formed by Acropora palmata, but colonies of A. cervicornis and the hybrid A. prolifera are also present. This study shows spatial distribution of colonies, thickets and live fragments of these species in the fore reefs. Snorkeling was used to perform the direct observations. The maximum diameter of 4,399 colonies of A. palmata was measured and the health of 3,546 colonies was evaluated. The same was done to 168 colonies of A. cervicornis and 104 colonies of A. prolifera. The influence of the location and marine currents on a number of living colonies of A. palmata was analyzed. For such purpose, reef crests were divided into segments of 500 m. The marine park was divided into two sectors: East and West. The Caballones Channel was used as the reference dividing line. The park was also divided into five reserve zones. We counted 7,276 live colonies of Acropora spp. 1.4% was A. prolifera, 3.5% A. cervicornis and 95.1% A. palmata. There were 104 thickets of A. palmata, ranging from eight to 12 colonies, and 3,495 fragments; 0.6% was A. cervicornis and the rest A. palmata (99.4%). In the East sector, 263 colonies (3.8% of the total), six thickets (5.8%) and 32 fragments (1%) of A. palmate were recorded. In the same sector, there were 11 fragments (50%) of A.cervicornis and two (2%) colonies of A. prolifera. Health of A. palmata was evaluated as good and not so good in the study area. Health of A. cervicornis was critical and health of A. prolifera was good in all five reserve zones. There was a significant increase in the number of colonies from east to west (Χ2 = 11.5, gl = 3.0, p = 0.009). This corroborates the existence of an important abundance differences between the eastern and the western region of the JRNP. A negative relationship was observed between the number of colonies and the distance from the channel (Χ2 = 65.0, df = 3.0, p < 0.001). The influence of the channel, for the live colonies of A. palmata is greater within the first 2,000 m. It then decreases until approximately 6,000 m, and no significant increase beyond. The orientation of the reef crests significantly influenced the abundance of the colonies (Χ2 = 15.5, df = 2.9, p = 0.001). The results presented here provide a baseline for future research on the status of the populations of Acropora spp., considering that there has been a certain recovery of the species A. palmata during the last 10–16 years. Given the current status of the populations of Acropora spp., conservation actions focusing A. cervicornis should be prioritized.

scholarly journals Effects of Domestic Livestock and Native Wildlife Grazing in Grand Teton National Park

1991 ◽  
Vol 15 ◽  
pp. 165-168
Author(s):  
Michael Smith ◽  
Jerrold Dodd ◽  
Uyapo Omphile ◽  
Paul Meiman
Keyword(s):  
Plant Community ◽  
National Park ◽  
Mule Deer ◽  
Snake River ◽  
Grand Teton National Park ◽  
Jackson Hole ◽  
Domestic Livestock ◽  
Wildlife Populations

The Snake River plains and foothill areas of Jackson Hole have been grazed by domestic livestock since settlement of the area. Wildlife populations, including elk, mule deer, and antelope have historically used and continue to use the area. Moose are currently relatively abundant and a small herd of bison have been introduced. Currently, livestock continue to use part of the area contained in Grand Teton National Park either as a concession or due to authorization by Park enabling legislation. Park managers need information concerning the effects of grazing by large ungulates on vegetation resources to assist in effectively managing grazing to achieve desired plant community goals.

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