Samuel K. Wasser

Reproductive Suppression Among Female Mammals: Implications for Biomedicine and Sexual Selection Theory

Female mammals experience a very high and often unappreciated rate of reproductive failure. Among human pregnancies alone, over 50 per cent fail between conception and parturition, and the majority of these failures are unexplained. These findings present important problems for evolutionary theory as well as for health care practices. This paper addresses these high rates of reproductive failure among mammals, by extending the work of a number of evolutionary biologists regarding the reproductive consequences of environmental adversity. The basic model upon which we elaborate, termed the Reproductive Suppression Model, argues that females can optimize their lifetime reproductive success by suppressing reproduction when future conditions for the survival of offspring are likely to be sufficiently better than present ones as to exceed the costs of the suppression itself. These costs are a function of reproductive time lost and the direct phenotypic effects of the suppression itself. To evaluate the benefits and costs of suppression, the following types of cues should be assessed: the females physical and mental health, her stage of reproduction, the physical and genetic status of her offspring, and the external conditions at the time of birth. We also examine various issues of social suppression, whereby the conditions for survival of offspring are a function of the reproduction and support of other group members. Under such conditions, some females may be able to improve current conditions for reproduction by suppressing the reproduction of others. Field data from our own work are presented, describing socially mediated reproductive competition among continuously breeding female yellow baboons and among female hoary marmots. Social suppression in other mammals is also evaluated, including that in human beings, and we conclude with some implications of the Reproductive Suppression Model for sexual selection theory regarding female-female reproductive competition, as well as human health care.

Techniques for application of faecal DNA methods to field studies of Ursids

We describe methods for the preservation, extraction and amplification of DNA from faeces that facilitate field applications of faecal DNA technology. Mitochondrial, protein encoding and microsatellite nuclear DNA extracted and amplified from faeces of Malayan sun bears and North American black bears is shown to be identical to that extracted and amplified from the same individuals tissue or blood. A simple drying agent, silica beads, is shown to be a particularly effective preservative, allowing easy and safe transport of samples from the field. Methods are also developed to eliminate the risk of faecal DNA contamination from hair present in faeces.

Evidence that ship noise increases stress in right whales

Baleen whales (Mysticeti) communicate using low-frequency acoustic signals. These long-wavelength sounds can be detected over hundreds of kilometres, potentially allowing contact over large distances. Low-frequency noise from large ships (20–200 Hz) overlaps acoustic signals used by baleen whales, and increased levels of underwater noise have been documented in areas with high shipping traffic. Reported responses of whales to increased noise include: habitat displacement, behavioural changes and alterations in the intensity, frequency and intervals of calls. However, it has been unclear whether exposure to noise results in physiological responses that may lead to significant consequences for individuals or populations. Here, we show that reduced ship traffic in the Bay of Fundy, Canada, following the events of 11 September 2001, resulted in a 6 dB decrease in underwater noise with a significant reduction below 150 Hz. This noise reduction was associated with decreased baseline levels of stress-related faecal hormone metabolites (glucocorticoids) in North Atlantic right whales (Eubalaena glacialis). This is the first evidence that exposure to low-frequency ship noise may be associated with chronic stress in whales, and has implications for all baleen whales in heavy ship traffic areas, and for recovery of this endangered right whale population.

Using DNA to track the origin of the largest ivory seizure since the 1989 trade ban

The illegal ivory trade recently intensified to the highest levels ever reported. Policing this trafficking has been hampered by the inability to reliably determine geographic origin of contraband ivory. Ivory can be smuggled across multiple international borders and along numerous trade routes, making poaching hotspots and potential trade routes difficult to identify. This fluidity also makes it difficult to refute a countrys denial of poaching problems. We extend an innovative DNA assignment method to determine the geographic origin(s) of large elephant ivory seizures. A Voronoi tessellation method is used that utilizes genetic similarities across tusks to simultaneously infer the origin of multiple samples that could have one or more common origin(s). We show that this joint analysis performs better than sample-by-sample methods in assigning sample clusters of known origin. The joint method is then used to infer the geographic origin of the largest ivory seizure since the 1989 ivory trade ban. Wildlife authorities initially suspected that this ivory came from multiple locations across forest and savanna Africa. However, we show that the ivory was entirely from savanna elephants, most probably originating from a narrow east-to-west band of southern Africa, centered on Zambia. These findings enabled law enforcement to focus their investigation to a smaller area and fewer trade routes and led to changes within the Zambian government to improve antipoaching efforts. Such outcomes demonstrate the potential of genetic analyses to help combat the expanding wildlife trade by identifying origin(s) of large seizures of contraband ivory. Broader applications to wildlife trade are discussed.

An evaluation of long-term preservation methods for brown bear (Ursus arctos) faecal DNA samples

Relatively few large-scale faecal DNA studieshave been initiated due to difficulties inamplifying low quality and quantity DNAtemplate. To improve brown bear faecal DNA PCRamplification success rates and to determinepost collection sample longevity, fivepreservation methods were evaluated: 90%ethanol, DETs buffer, silica-dried, oven-driedstored at room temperature, and oven-driedstored at −20 °C. Preservationeffectiveness was evaluated for 50 faecalsamples by PCR amplification of a mitochondrialDNA (mtDNA) locus (∼146 bp) and a nuclear DNA(nDNA) locus (∼200 bp) at time points of oneweek, one month, three months and six months. Preservation method and storage timesignificantly impacted mtDNA and nDNAamplification success rates. For mtDNA, allpreservation methods had ≥ 75% success atone week, but storage time had a significantimpact on the effectiveness of the silicapreservation method. Ethanol preserved sampleshad the highest success rates for both mtDNA(86.5%) and nDNA (84%). Nuclear DNAamplification success rates ranged from 26–88%, and storage time had a significant impacton all methods but ethanol. Preservationmethod and storage time should be importantconsiderations for researchers planningprojects utilizing faecal DNA. We recommendpreservation of faecal samples in 90% ethanolwhen feasible, although when collecting inremote field conditions or for both DNA andhormone assays a dry collection method may beadvantageous.

Combating the Illegal Trade in African Elephant Ivory with DNA Forensics

International wildlife crime is burgeoning in this climate of global trade. We contend that the most effective way to contain this illegal trade is to determine where the wildlife is being removed. This allows authorities to direct law enforcement to poaching hot spots, potentially stops trade before the wildlife is actually killed, prevents countries from denying their poaching problems at home, and thwarts trade before it enters into an increasingly complex web of international criminal activity. Forensic tools have been limited in their ability to determine product origin because the information they can provide typically begins only at the point of shipment. DNA assignment analyses can determine product origin, but its use has been limited by the inability to assign samples to locations where reference samples do not exist. We applied new DNA assignment methods that can determine the geographic origin(s) of wildlife products from anywhere within its range. We used these methods to examine the geographic origin(s) of 2 strings of seizures involving large volumes of elephant ivory, 1 string seized in Singapore and Malawi and the other in Hong Kong and Cameroon. These ivory traffickers may comprise 2 of the largest poaching rings in Africa. In both cases all ivory seized in the string had common origins, which indicates that crime syndicates are targeting specific populations for intense exploitation. This result contradicts the dominant belief that dealers are using a decentralized plan of procuring ivory stocks as they became available across Africa. Large quantities of ivory were then moved, in multiple shipments, through an intermediate country prior to shipment to Asia, as a risk-reduction strategy that distances the dealer from the poaching locale. These smuggling strategies could not have been detected by forensic information, which typically begins only at the shipping source.

Long‐Term Impacts of Poaching on Relatedness, Stress Physiology, and Reproductive Output of Adult Female African Elephants

Widespread poaching prior to the 1989 ivory ban greatly altered the demographic structure of matrilineal African elephant (Loxodonta africana) family groups in many populations by decreasing the number of old, adult females. We assessed the long-term impacts of poaching by investigating genetic, physiological, and reproductive correlates of a disturbed social structure resulting from heavy poaching of an African elephant population in Mikumi National Park, Tanzania, prior to 1989. We examined fecal glucocorticoid levels and reproductive output among 218 adult female elephants from 109 groups differing in size, age structure, and average genetic relatedness over 25 months from 2003 to 2005. The distribution in group size has changed little since 1989, but the number of families with tusked old matriarchs has increased by 14.2%. Females from groups that lacked an old matriarch, first-order adult relatives, and strong social bonds had significantly higher fecal glucocorticoid values than those from groups with these features (all females R(2)= 0.31; females in multiadult groups R(2)= 0.46). Females that frequented isolated areas with historically high poaching risk had higher fecal glucocorticoid values than those in low poaching risk areas. Females with weak bonds and low group relatedness had significantly lower reproductive output (R(2)[U]=0.21). Females from disrupted groups, defined as having observed average group relatedness 1 SD below the expected mean for a simulated unpoached family, had significantly lower reproductive output than females from intact groups, despite many being in their reproductive prime. These results suggest that long-term negative impacts from poaching of old, related matriarchs have persisted among adult female elephants 1.5 decades after the 1989 ivory ban was implemented.

Patterns of molecular genetic variation among African elephant populations

The highly threatened African elephants have recently been subdivided into two species, Loxodonta africana (savannah or bush elephant) and L. cyclotis (forest elephant) based on morphological and molecular studies. A molecular genetic assessment of 16 microsatellite loci across 20 populations (189 individuals) affirms species level genetic differentiation and provides robust genotypic assessment of species affiliation. Savannah elephant popula‐tions show modest levels of phylogeographic subdivision based on composite microsatellite genotype, an indication of recent population isolation and restricted gene flow between locales. The savannah elephants show significantly lower genetic diversity than forest elephants, probably reflecting a founder effect in the recent history of the savannah species.

Effect of Long‐Term Preservation Methods on Fecal Glucocorticoid Concentrations of Grizzly Bear and African Elephant

Fecal hormone analysis has become a powerful noninvasive tool for the study of animal endocrine status and stress physiology (Graham and Brown 1997; Wasser et al. 1997a; Whitten et al. 1998; Goymann et al. 1999; Mostl et al. 1999; Foley et al. 2001; Creel et al. 2002; Lynch et al. 2002; Morrow et al. 2002). Variation in field and storage conditions makes it essential to know whether fecal steroid concentrations change with the method and duration of sample storage. Lyophilization (freeze-drying) with subsequent storage at or below 20 C is generally regarded as the most reliable method of long-term fecal hormone preservation (e.g., Wasser et al. 1988; Terio et al. 2002). However, lyophilizers are not widely available, and therefore investigators have turned to a variety of other fecal storage methods, including freezing at 20 C, preservation in ethanol, and/or drying the feces with silica, ovens, solar radiation, fires, or other drying methods (Wasser et al. 1988; Whitten et al. 1998; Foley et al. 2001; Tecot 2001). Yet, some of these preservation methods may result in significant changes in immunoreactive hormone concentrations, varying with the preservation method, species, and hormone. In this article, we report effects of several commonly used fecal preservation methods on immunoreactive glucocorticoid concentrations in feces of two species, African elephant (Loxodonta africana) and grizzly bear (Ursus arctos horribilis), over a 2-yr period. Five different preservation methods were chosen for comparison: no preservative, oven-drying at 45 C, silicadrying, 90% ethanol, and lyophilization, each with subsequent storage either at room temperature or in a 20 C freezer. Con-

The influences of wolf predation, habitat loss, and human activity on caribou and moose in the Alberta oil sands

Woodland caribou (Rangifer tarandus caribou) and moose (Alces alces) populations in the Alberta oil sands region of western Canada are influenced by wolf (Canis lupus) predation, habitat degradation and loss, and anthropogenic activities. Trained domestic dogs were used to locate scat from caribou, moose, and wolves during winter surges in petroleum development. Evidence obtained from collected scat was then used to estimate resource selection, measure physiological stress, and provide individual genetic identification for precise mark–recapture abundance estimates of caribou, moose, and wolves. Strong impacts of human activity were indicated by changes in resource selection and in stress and nutrition hormone levels as human-use measures were added to base resource selection models (including ecological variables, provincial highways, and pre-existing linear features with no human activity) for caribou. Wolf predation and resource selection so heavily targeted deer (Odocoileus virginiana or O hemionus) t...