Introduction

We envision a long-term study (5+ years) because we have data that indicate that mongooses have a maximum life span on St. Croix of greater than five years. Initially, we would like to do mark-recapture studies in habitats where mongooses, rats, mice, and hutias are known to coexist, and in habitats where they do not coexist. These would be done to help address the following:

I. Competition and predation. We have evidence that mongooses eat rats (published stomach contents analyses). We have some evidence that rats and mice do not coexist at high densities. We have some evidence that indicates in areas where the three species coexist, mongoose and mouse populations are high, and rat populations are low.

1. Do rats and mice compete for food? We can answer this question through fecal pellet analysis. (I published a paper many years ago on a dietary analysis of jackrabbits in Baja California based upon fecal analysis.) To analyze the diets of rats and mice we can collect fecal pellets from traps and do microscopic analysis of the contents. All we need is a plant reference collection (slides of epidermal cells from local plants including leaves, seeds, stems, flowers, and fruits) and a compound microscope. This should allow us to estimate the degree of overlap of at least one dimension of their niches.

2. Do mongoose depress rat populations causing mouse populations to increase? I would prefer to address this question through live trapping instead of diet analysis for two reasons. (1) We would need to conduct stomach content analysis of mongooses and that would require sacrificing them. (2) The presence of mongooses may in itself be a deterrent to rats, so a stomach content analysis may be misleading.

3. How does the presence of one species influence the life history traits of another species? We can determine the age structure and sex ratios of each species in areas where they coexist, in areas where only two of the three species coexist, and in areas where only one species exists. These data should provide us with insight into the interactions.

4. Can we model these interactions? Yes students will be able to develop models using R, NetLogo, and spreadsheets using the field-collected data.

5. What will be the value of these models? These models serve several functions. (1) Improve student understanding of population demographics in small mammals. (2) Improve student understanding of the role of mathematical models in the study of natural populations. (3) Improve student quantitative skills. (4) Models can serve as the foundation for the development of any control programs.

II. Why do we want to know about the life history of these three species?

1. Because mongooses carry rabies that can be readily transmitted to domesticated mammals (livestock and pets).

2. Because rats and mice also carry diseases such as leptospirosis.

3. We have evidence that rats prey upon newborn hutias in their nests. Most hutias are endangered on Cuba.

After we have a better understanding of the life histories of rats, mice, and mongooses in Cuba, then we should consider sacrificing mongooses to determine level of immunity and levels of infection. We can answer the following questions

1. How do the rates of immunity and infection fluctuate?

2. Are they inversely related as suggested by Everard in Grenada?

Time Line

Data Gathering Cycle

Initial Instructors receive a kit that includes a computer or computers, traps, and supplies necessary for collecting samples. Each semester, new student teams go through a semester long process that includes a graded series of phases to:

Each phase will include opportunities to share experiences informally via chat and/or threaded discussion.

In the initial cycle we train the instructors on data gathering and test the communications systems. In subsequent cycles, we bring up nodes in other areas by having us (or other previous participants) conduct workshops.