Robert J. Wiese

Asian elephants are not self‐sustaining in North America

Demographic analysis of the captive Asian elephants in North America indicates that the population is not self-sustaining. First year mortality is nearly 30%, but perhaps more important, the fecundity is extremely low (Mx = 0.01–0.02) throughout the prime reproductive years. Without continued importation or a drastic increase in birth rates, the Asian elephant population in North America will drop to approximately 10 elephants in 50 years and be demographically extinct. Model mortality and fecundity curves needed to establish a self-sustaining Asian elephant population in North America show that fecundity must increase four to eight times the historical rates. Emerging techniques such as artificial insemination may assist in making the goal of a self-sustaining population more realizable by allowing reproduction by the numerous females that do not have access to a male, but other obstacles exist as well. A self-sustaining population will present challenges such as maintaining the significant number of male offspring that will be produced. Importation of young females from documented self-sustaining populations overseas is one option that would alleviate the need for a self-sustaining Asian elephant population in North America and the number of imports per year would be minimal. Zoo Biol 19:299–309, 2000.

State of the North American African elephant population and projections for the future

The African elephant has historically received less attention in the captive community than the Asian elephant. One manifestation of this lack of attention is that only 25 African elephant calves had been born in captivity in North America as of 1 January 1999. With the recent attention to both elephant species, it is imperative to evaluate the African elephant’s potential to maintain a self-sustaining population in North America. Review of the raw data indicates that African elephants have reproduced poorly and experienced low juvenile survival in North America. However, using realistic life table models,the future of the North American African elephant population can be predicted. The current population is relatively young compared to the captive Asian elephant population and has a much greater potential to become self-sustaining with increased focus and efforts toward reproduction. Unlike the Asian elephant population, the African elephant population may be able to become self-sustaining without further importation, if reproduction and juvenile survivorship increase significantly in the next 10 years. Zoo Biol 19:311–320, 2000.

Elimination of inbreeding depression from captive populations: Speke's gazelle revisited

In a review of the evidence for reduction in the severity of inbreeding depression in Spekes gazelle [Templeton and Read, pp. 241–261 in Genetics and Conservation: A Reference for Managing Wild Animal and Plant Populations, C.M. Schoenwald-Cox, S.M. Chambers, B. MacBryde, and L. Thomas, eds., Reading, MA, Addison-Weley, 1983; Templeton and Read, Zoo Biology 3:177–199, 1984] a flaw was found in the statistical analysis. Reanalysis of the 1983 data showed no significant reduction in the severity of inbreeding depression. An updated analysis using data from the 1992 Spekes Gazelle North American Regional Studbook [Fischer, St. Louis, St. Louis Zoological Park, 1993] also showed no significant reduction in the severity of inbreeding depression. While there is empirical evidence suggesting reduction in the severity of inbreeding depression in captive populations is possible through reduction of the founder base, maintenance of genetic variation must remain the primary goal of genetic management strategies for captive populations of exotic wildlife. Zoo Biol 16:9–16, 1997.

Lineage Identification and Genealogical Relationships Among Captive Galápagos Tortoises

Genetic tools have become a critical complement to traditional approaches for meeting short- and long-term goals of ex situ conservation programs. The San Diego Zoo (SDZ) harbors a collection of wild-born and captive-born Galápagos giant tortoises (n = 22) of uncertain species designation and unknown genealogical relationships. Here, we used mitochondrial DNA haplotypic data and nuclear microsatellite genotypic data to identify the evolutionary lineage of wild-born and captive-born tortoises of unknown ancestry, to infer levels of relatedness among founders and captive-born tortoises, and assess putative pedigree relationships assigned by the SDZ studbook. Assignment tests revealed that 12 wild-born and five captive-born tortoises represent five different species from Isabela Island and one species from Santa Cruz Island, only five of which were consistent with current studbook designations. Three wild-born and one captive-born tortoise were of mixed ancestry. In addition, kinship analyses revealed two significant first-order relationship pairs between wild-born and captive-born tortoises, four second-order relationships (half-sibling) between wild-born and captive tortoises (full-sibs or parent-offspring), and one second-order relationship between two captive-born tortoises. Of particular note, we also reconstructed a first-order relationship between two wild-born individuals, violating the founder assumption. Overall, our results contribute to a worldwide effort in identifying genetically important Galápagos tortoises currently in captivity while revealing closely related founders, reconstructing genealogical relationships, and providing detailed management recommendations for the SDZ tortoises.