DUCKLING WOOD DUCKS, OTTERS, AND A WEEK OFF

Sometimes they do their own thing

 at other times we do things together

and every now and then ... it's the same but different?

SAMPLING FOR AVAILABLE FOOD RESOURCES

Even though Western pond turtles forage in the water, the aquatic ecosystem has strong links to the adjacent terrestrial ecosystem. Further, it is common for a terrestrial insect to land in or near the water and when a turtle sees it, they eat it. Therefore, I am sampling both habitats, as you can see from my previous posts that include pictures of terrestrial insects (i.e., beetles and grasshoppers). I use brush net sweeps along the bushes and bankside vegetation to sample the terrestrial ecosystem. In the aquatic ecosystem, I use a D-net to pull samples from the emergent vegetation and the substrate (creek bottom landscape). To do this I jab the net into the sample area and then with a twisting and jabbing motion I stir the area up and then withdraw the sample. My other tool is activity-traps that I fashion from plastic soft and juice drink bottles. I put a small amount of bait, usually sardines, inside of them to attract carnivores and scavengers, which largely encompasses the feeding habits of all the organisms living there. It seems that nobody turns down a free meal!

The direct impact on my research is that I can readily identify organisms or parts of them I find in the stomach contents of Western pond turtles. In addition, it gives me peripheral information such as the variety of available food resources and its seasonality. In the future, I want to examine in grater detail, because it is helpful when measuring the effects of human activity on these ecosystems.

YIKES, THE OTTERS ARE BACK!

The "calling cards" or scats left behind by otters are useful tool for me and let other predators in the area know they are present. 

Otter feces rich in crayfish parts.

Generally, North American river otters (Lontra canadensis) seem to be largely absent from Santa Rosa Creek. Occasionally I see an occasional scat (feces), but rarely encounter them until near the end of July. When they move into the area to feed on crayfish, they are competing with Western pond turtles for the same food resource. The larger, faster mammal out competes the turtles for the most available food resource.

In addition, they also attempt to remove the punctured cans of sardines I put in turtle traps as bait. They dislodge the traps from their moorings, sinking them, making it possible to drown any turtle that is inside. To prevent this kind of incident I set out activity traps to discover if they are present during mid-July along the areas of Santa Rosa Creek I plan to work. These baited traps, filled with sardines, attract the otters and they drag them from place to place while trying to remove the sardines.

On July 20, 2012, I thought I heard otters foraging in the bulrushes, found scats (feces), and crayfish parts along the section of the bank I was planning to work. Because of this, I set out two traps to confirm my suspicions. The next day, I found them buried deep inside the emergent vegetation and bulrushes instead of being along the edge, a clear sign that otters are present. My final confirmation was hearing an otter yipping at me, as if to warn me off, as I approached the area to retrieve the traps.

In addition, they were working along a nearby bike trail I use for access to other sites. Hence, I took a week off, examined and compiled my data, and took some time to rest and gather my thoughts. Therefore, I did not add to the blog last week.

OVERVIEW AND METHODS

Early in May there were ten crossing the water

Hidden in plain view are two, maybe three - see if you can find them.

Yep, it's going to be duckling Wood Ducks for the next few days!

OVERVIEW

If you recall, I am developing a model for my research methods because of reading a wide variety of research and critiques of the methods for doing a diet and feeding ecology study. However, I did not discuss the reason for doing the research, its rationale. Throughout much of its range in Southern California and in Washington State the Western pond turtle is largely extinct. Much of this happened as land development, especially urbanization, spread throughout those regions. It is unlikely but possible this is a coincidence. Today the Western pond turtle Washington State gives it total legal protection and has partial protection in both California and Oregon. Because of disagreements in the scientific community and lack of evidence U.S. Fish and Wildlife are unwilling to give it endangered status. This is largely because there is no scientific information on its population size outside of areas where they are essentially missing. In fact, one agency decried the fact there is so little information that it makes it impossible to make an informed decision. Therefore, I chose to do research that avoids the major criticisms of diet and feeding ecology examinations, uncover some of the effects that may help explain their disappearance because of land development, and provide information for policy makers.

Consequently, I am examining the diet of Western pond turtles during the season they most actively feed, May through August. Further, I use activity traps to determine what food resources are available when I trap turtles. Consequently, many of my previous posts depict the various organisms they eat. Finally, I am choosing to tangentially investigate (e.g., as an aside) ways to inform citizens about my research (i.e., this blog). In addition, to see if my methods may be helpful to them, I am communicating by email or in person with city and county agencies making policies that affect the Western pond turtles living in the waterway. My goal in the future is to do similar research and spend more time examining the ecosystem in ways that may foster citizen awareness and policymaker decision making that promotes sustainable use of these resources.

THEN METHODS

After the overview and rationale for a research project, the next most important aspect is the methods I am using. Since my previous posts show some of the results of using activity traps, I will explain I make and use them. Then I will move on to trapping turtles, radio telemetry, and other processes such as gastric lavage and anesthesia.

Further, since this forum informal I will also cover other topics. For example, my current examination of the possible negative effects of RoundUp and its cousin pesticides I am doing for a colleague.

CHEMICALS, THE ECOSYSTEM, AND YOU

The following article excerpts reveal some of the possible negative effects of the pesticide, sometimes because of the interactions between various ingredients in it. The following is an overview that was published on the topic. Later I will publish excerpts from journal articles including the one reported in this article. 

Roundup Revelation: Weed Killer Adjuvants May Boost Toxicity (Bonn, 2005)

                 

 “Although the glyphosate-based herbicide RoundUp is generally thought to be less toxic to the ecosystem than other pesticides, concerns about its effects on human reproduction persist. In a study in Ontario, Canada, exposure of male farmers to glyphosate-based herbicides was associated with an increase in miscarriage and premature birth in farm families. Seeking an explanation for these pregnancy-related problems, researchers at France's Universite de Caen investigated the effects of the full Roundup formulation and glyphosate alone on cultured human placental cells The herbicide, they found, killed the cells at concentrations far below those used in agricultural practice.”

·      “Surprisingly, they also found that Roundup was at least twice as toxic as glyphosate alone. Virtually all previous testing of Roundup for long-term health damage has been done on glyphosate rather than on the full herbicide formulation, of which glyphosate makes up only around 40%. The remainder consists of inactive ingredients including adjuvants, chemicals that are added to improve the performance of the active ingredient. Roundup's main adjuvant is the surfactant polyethoxylated tallowamine, which helps glyphosate penetrate plant cells.”

·      “Polyethoxylated tallowamine is just being investigated but indications are that it has some remarkable toxic effects. Check out pub med and there is a hint. This kind of investigation should be done by any reputable scientist before using this chemical AND this points to the problems with the current system regarding the release of a chemical for use on food crops.”

·      “No one is sure how Roundup interferes with reproduction, so the team also tested whether it, like other pesticides, would disrupt the activity of aromatase (an enzyme that regulates estrogen synthesis) in placental cells. Aromatase activity was measured after 1 hour and 18 hours. The study showed that the effect of Roundup on cell viability increased with time and was obtained with concentrations of the formulation 10 times lower than those recommended for agricultural use. Roundup also disrupted aromatase activity at concentrations 100 times lower than those used in agriculture. The researchers suspect that the adjuvants used in Roundup enhance the bioavailability and/or bioaccumulation of glyphosate. How these findings translate into activity of Roundup in the human body is hard to say. The French researchers point out that serum proteins can bind to chemicals and reduce their availability and therefore their toxicity to cells. Nevertheless, the authors conclude that the demonstrated toxicity of Roundup, even at concentrations below those in agricultural use, could contribute to some reproduction problems.”

BIBLIOGRAPHY

Bonn, D. (2005). Roundup Revelation: Weed Killer Adjuvants May Boost Toxicity. Environmental Health Perspectives, 113(61), A404.

RoundUp herbicide, ducks and geese

RoundUp the herbicide that alters genes

A friend called me earlier today and needed me to collaborate on a comment he is going to make on a U.S. Navy environmental impact report. Specifically, they want to use RoundUp to knock down trees near the power lines in his community. Our local water agency here does not want to use it because of some problems that have come to light about it. In fact, I have been preparing some information for them on the topic - to support their unwillingness to use it. Even though we allow its use on food crops! 

You can Google it and find some things out but is largely non-technical.

 For example:

“Medical reports link exposure to glyphosate herbicides with short-term symptoms including blurred vision, skin problems, heart palpitations, and nausea. Studies have also found associations with increased risk of miscarriages, premature birth, non-Hodgkin’s lymphoma, and diabetes. Formulations in which glyphosate is combined with other ingredients can be more acutely toxic than glyphosate alone (6, pgs. 5-8). Monsanto, a major manufacturer of glyphosate-based herbicides, was challenged by the Attorney General of New York State for making safety claims similar to those now being repeated by the U.S. State Department. In an out-of-court settlement in 1996, Monsanto agreed to stop advertising the product as "safe, non-toxic, harmless or free from risk”.

“New York State's Attorney General has sued Monsanto for claiming that RoundUp is "safe" and "environmentally friendly."  This suit ended in a settlement with Monsanto in which Monsanto agreed to cease and desist from using these terms in advertising RoundUp in the state of New York.  Monsanto, while not admitting any wrongdoing, paid the state of New York $250,000 in settlement of this suit.  When Monsanto violated the first settlement agreement by advertising within New York that RoundUp is "safe," a second agreement was negotiated.”

I took this mural like photograph at a nearby urban lake when the Canada Geese (Branta canadensis) were sitting on their nests. They are so large bodied because they are herbivores and this is common for plant eaters because they need to eat a lot of food to get the nutrition they need. For some folks the by product of this diet (feces) is a problem when it is in their parks. However, the other waterfowl that would normally be there move out, largely because of human and pet activity in the water. Therefore, it is easy for me to be understanding and appreciate their presence.

So, I have two good reasons to be investigating RoundUp. Thus far, the claims that it is not safe because it modifies DNA and inhibits cell function and interferes with reproduction are true. I cannot post these peer-reviewed articles BUT you can email me and I will send the peer-reviewed information to you. One in particular is interesting because it is challenged and the author does an effective job of refuting the allegations. 

It is somewhat disheartening to discover that scientists who uncover these kinds of problems do not speak out. However, it is not surprising since few if any scientists are willing to study ethics. In fact, I am attending a two-year long seminar at U.C. Berkeley and one presenter, a bioethicist, was given the task of discussing this with cell and molecular biologists by the National Science Foundation - they refused to participate. 

THE LONG-JAWED ORB WEAVER

Sometimes ... nature speaks to me and I listen.

   And I make something ...

   more out of it - just for me.

THE EVOLUTION OF A PROJECT

... and the beauty of some non-natives  

Yesterday, I mentioned differential digestion rate and hinted that it is important. Now it is time to find out how considering it and other pieces of information shaped my methods.

Specifically, when I was first developing a proposal about doing a diet study I read a number of papers and many weighed and measured the volume of the items in the animal’s stomach. Also using these values, they made comparisons using age, size, and gender. It was easy to embrace the idea of doing this because allows me to report on my research results using quantitative methods. 

In addition to reading papers on turtle diets, I read ones done by ichthyologists (fish biologists) and ornithologists (bird biologists). Both groups have a long history of doing diet studies. One point they both discuss is that it is impractical to attempt to determine what percentage of the diet is a particular food resource or kind of food resources. This is because each food item has a different rate of digestion (differential digestion rate). In addition, turtles eat whenever food is available rather than on a schedule. Further, preserving the contents of the stomach in any preservative alters the weight and mass of some items but not others. For example, ethanol alcohol (a common preservative) dissolves fats, thereby reducing the mass of fats.

The only way I can reasonably discuss what foods make up their diet on a percentage basis is to lock them in cage (i.e., a zoo) and present them with a wide variety of food choices and measure what they eat each day. Of course, the minute you put an animal in an artificial setting its exercise and diet change.

Therefore, all I can do is portray what they were eating before capturing them. The next time I will tell will begin to explain what I am doing to add robustness to the research.

"Many weeds and ornamental plants have been here so long that the soil and the organisms in it are an ideal habitat for them. Because of this, many native plants cannot successfully live in these soils. In fact, many of the remaining native animals rely on these non-native plants. This is sometimes vexing for urban ecologists."