Intersci, Fall, 1994

 

Natural History Museum Collections and Conservation Biology

 

by Andrea Jesse

 

Today in the world of biology where the focus is on endangered species and how we might save them from extinction, museum collections of dead specimens might seem rather archaic. In fact, natural history museum collections are vital to biological conservation efforts. The average lifespan of most organisms is quite brief; in death, however, they can provide information to scientists across centuries or longer. Natural History museums are vestiges of historical information pertaining to the organisms with whom we share the planet; much of this information provides the cornerstone to ensuring their long term survival.

People have been collecting and categorizing organisms for centuries. The Linnaen system of nomenclature, developed over 200 years ago, is still being used to classify organisms. Today, however, interests range beyond mere taxonomy. Systematics has evolved to where relationships between organisms are being hypothesized based on similarities determined with the use of morphometric (physical attributes) as well as genetic measurements (DNA analysis). Systematics has been and continues to be one of the major focuses of research on museum collections. In addition, with efforts to save populations of organisms at risk of extinction, natural history museum research has played an ever increasing role in conservation.

The California Academy of Sciences (CAS) located in Golden Gate Park in San Francisco houses several natural history collections. Many people visiting the numerous live and historical exhibits on the ground floor of CAS are unaware of all the research activity going on elsewhere in the building. The activity surrounds six natural history research departments and their accompanying collections: they are Botany, Entomology, Herpetology, Ichthyology, Invertebrate Zoology & Geology, and Ornithology & Mammalogy. Each of these departments is actively used by scientists as part of their investigative research. Interested scientists either perform their research at CAS, or specimens of interest are sent to them. In this way, acting as a resource for scientists, specimens in museums promote conservation by curtailing extraneous collecting.

Beyond the obvious physical attribute information associated with each specimen, specimens contain data on dates and localities. That is to say that museum collections provide information on ranges and periods of time in which species occurred within certain localities. Such data have obvious implications for someone looking into current versus former distributions of species. This can be of particular importance when a species is endangered since one would try to preserve the unique habitats on which these organisms depend.

What follows is an attempt to introduce the reader both, generally, to the role of natural history museum collections in the plight of conservation and, more specifically, to CAS’s role in these efforts.

The cutting edge research currently going on in systematics involves DNA analysis. Using PCR (Polymerase Chain Reaction) amplification techniques one is able to clone DNA from all manner of samples, including museum study skins. This allows one to compare genetic material between individuals, populations and species. This new tool is a boon for museum systematic research because it is now possible to look at relatedness between groups past and present.

Douglas Bell, a research associate in the Department of Ornithology & Mammalogy at CAS, has a project underway in which he hopes to compare the genetics of former Peregrine Falcon populations in North America with reestablished populations. To do this, skin samples are taken from study skins of Peregrines with the department’s collection. From these samples, PCR amplified genes are extracted and sequenced. These genes are compared to genes extracted from live individuals from the three North American recognized subspecies in order to compare the level of present genetic differentiation with past genetic differentiation.

Knowledge of levels of genetic diversity is critical to conservation efforts. Both inbreeding and outbreeding of individuals that are not genetically compatible can be detrimental to populations at risk. Bell’s findings will be instrumental to preserving this high profile species whose populations have teetered at the brink of extinction.

In the early 1960's raptor biologists first began to realize the trouble Peregrine Falcons were having in producing successful offspring. Researchers such as Derek Ratcliffe in England and David Pekall in Canada discovered parallels between the use of the pesticide DDT and the inviability of Peregrine eggs. Hickey and Anderson (1968) did the definitive work in targeting DDT and its metabolic breakdown, DDE, as the cause of the decline in this species.

DDT began to be used heavily in the U.S. and elsewhere around the world after WW II as an all-purpose pesticide. What wasn’t immediately apparent is that in the environment it is picked up by fish, shorebirds and grain-eating birds. These organisms are primary food-items for many raptors, most notably the Peregrine Falcon. Being high on the food chain, the Peregrine suffered high concentrations of DDT in its tissues. Problems showed themselves when, in attempts to breed, egg shells are thinned due to the presence of the toxin in the mother bird’s body.

Hickey and Anderson (1968) used museum specimens of Peregrine Falcon eggs to track egg shell thinning. This thinning caused eggs to rupture prematurely, leading to population declines and eventually an “endangered” status. Thinned museum eggs provided the proof that DDT was at fault since each of the eggs examined had with them data on where and when they were collected. Thus, Hickey and Anderson were able to track the effects of DDT on the Peregrine over time. This evidence was instrumental in the eventual ban of the pesticide in this country.

The Peregrine provides an excellent example of how museum collection specimens can be used to identify a problem and come up with solutions to ensure species survival.

Viability is also an issue in the Botany department with endangered plant species. Tom Daniel, Curator of Botany, working with the Center for Plant Conservation, has been looking into the viability of herbarium seeds for repopulation of endangered species. Germination trials are underway for some populations that have been eliminated due to disruption of their environment. In this way he hopes to recover genetic resources that would otherwise be lost forever. Daniel hopes to eventually recreate populations of these rare and/or extinct species and to restore communities to their original conditions.

Disruption of plant and animal habitats by human activity through “development” such as building construction, creating grazing land for domestic animals, etc. has adversely affected organisms of most every taxonomic group on the planet.

Sometimes the smallest of species get overlooked when one considers the conservation of endangered species. What people don’t always realize is the critical role such small species play in the dynamics of ecosystems. Insects are responsible for much of the pollination that takes place among plants. Insects are also food for numerous amphibians, reptiles, birds and mammals. Therefore, their conservation, as well as the more “high-profile” species, must not be overlooked.

The Department of Entomology at the California Academy of Sciences houses one of the largest insect collections in the world. The collection contains an estimated 8 ½ million specimens representing ¼ million species. Western U.S. species are especially well represented. Considering there are more species of insects in the world than all other species combined, a large, well represented collection like the one at CAS is certainly important to a greater understanding of the diversity of the world’s insects. New species of insects are continually being described. When someone finds what they believe to be a new species they must then compare it to other specimens in museum collections and field guides to be sure that it is in fact unique and to determine the group to which it belongs.

Field guides play a vital role in identification of organisms in the field. The pictures in field guides used to identify species are most often drawn using museum specimens as models.

Beyond identifying what’s living today, specimens in museum collections are often the only evidence that something lived in the past. According to collections manager Norman Penny, the entomology collection at CAS has several presumed extinct species of butterflies. Butterflies like these in collections may be the only real evidence that these species ever existed. He says “Without this kind of baseline information it is impossible to create actual extinction rates.” In addition, specimens are used to study relationships between extinct and extant forms.

Distribution patterns of species of special concern can also be created using data from museum specimens, Norman points out, which show areas of overlap between species, so that critical areas of conservation can be preserved. In addition, one can monitor the health of an ecosystem using insect locale data, since insects are fundamental to reproductive cycles in plants and food webs of many vertebrates.

The Department of IZ&G (Invertebrate Zoology & Geology) at CAS houses invertebrate species other than insects, including crustaceans (e.g. barnacles, crabs, shrimp); mollusks (e.g. nudibranchs); polychaete worms; echinoderms (e.g. sea urchins); and diatoms (minute planktonic unicellular or colonial algae with silicified skeletons). Some groups (most notably the crustaceans and mollusks) are important for human consumptions. Museum collections can be used to monitor invertebrate population dynamics over time. For example, one can look at samples of shrimp taken from San Francisco Bay years ago and compare them to samples taken today. In so doing one can measure species changes over time and look at numbers of invasive species that might be interfering with populations of target commercial species. In addition on can use specimens as bio-indicators of pollution levels in the bay or elsewhere by conducting bioassaysto measure the amounts of heavy metals, etc, in their tissues and comparing results to bay levels of toxins.

The IZ&G collection, according to collections manager Bob Van Syoc, houses one of the world’s most significant holdings of three species of invertebrates at risk of extinction. The Trinity Bristle Snail (Monodenia setosa) has remnant populations living in the Trinity Alps; it is listed by the State as threatened. The collection also houses two endangered species, the California Fresh-water Shrimp (Syncaris pacifica), once common to freshwater streams in northern California, and the Shasta Crayfish (Pacifasticus fortis), currently known to live in only a few lakes in northern California.

Richard Mooi, who chairs the IZ&G department, has begun charting the narrowing distribution of sea urchins in a restricted range of Belize. Using data from the museum collection, he is able to track range reductions resulting from a recent hurricane in the area. Sea urchins from the CAS collection are also being utilized to assess the effects of nuclear waste dumping around the Farallon Islands off the coast of San Francisco. Radioactive decay of waste and subsequent contamination can be monitored by examining developmental abnormalities in the sea urchin.

Location data for endangered species of invertebrates taken from museum specimens have been used to prevent development of some natural areas. Taking advantage of laws designed to protect endangered species, environmentalists have used data from museum specimens from a specific locality targeted for development to show the existence of an endangered species in the area, thus protected the area from exploitation by profit seeking individuals. The specific endangered species is protected, and serendipitously, many other species along with it.

The Galapagos Archipelago flora and fauna are well represented in the collections at CAS. Historically these specimens are of the utmost importance considering Charles Darwin based much of his theory of natural selection on the natural wonders found on these islands. Charles Darwin’s theory provided the mechanism for evolution. His work changed the way we perceive the world. The world is now recognized as a dynamic place in a constant state of motion with organisms forever adapting to changing environments. These adaptations can easily be seen by examining the different bills of species of Darwin’s Finches adapted for different food items. This evidence of radiation of a taxon to fill a variety of niches gives one a greater appreciation of the complexity nature offers and the delicate balance that we must be careful to preserve.

The Department of Ornithology and Mammalogy at CAS houses the world’s most significant holdings of Darwin’s Finches outside of the Galapagos Islands themselves. They were collected around the turn of the century. Today the islands are strictly protected; collection has been reduced to almost zero. For someone to study specimens of these unique finches they must invariably turn to CAS.

The Department of Herpetology (amphibians and reptiles) at CAS houses the world’s most important collection of Galapagos tortoises outside of the islands. Recently a visiting researcher used the collection in his attempts to track species of Galapagos tortoises living in zoos. He used skin samples taken from collection specimens to determine the DNA of know species to compare with the DNA of zoo tortoises to find out if any representatives from extinct species are alive in zoos. If results are positive, individuals of like species may be brought together for captive propagation and possible future repopulation of the islands. The results of his study are not yet in, but this example shows the possibility for life to arise from the abyss of extinction through the use of museum specimens.

Beyond the Galapagos tortoises, the Herpetology department houses many species found only on the Archipelago including the Marine Iguana, the only lizard known to spend much of its time in salt water. Unlike specimens that were preserved in formalin, the Marine Iguanas that were preserved in alcohol have the potential for use in DNA analysis. Formalin is a fixative that is useful to preserve the gross morphology of organisms. Unfortunately it degrades DNA making DNA analysis difficult if not impossible. The Herpetology department is still actively collecting specimens for future DNA work. Tissue samples are preserved in alcohol or are frozen to ensure nucleic acid integrity.

More than anything else the Herpetology collection is used to compare past and current distributions of populations, according to collections manager Jens Vindum. In the last five years he has conducted queries on over 200,000 specimens for interested scientists the world over. Amphibians are of special concern since it appears that populations of frogs and salamanders worldwide are declining. In the Pacific Northwest, researchers from the Department of Wildlife in Olympia used distribution records from collection specimens in their assessment of the current distribution status of ranid frog populations believed to be at risk.

Bob Drewes is a curator in the Herpetology department. He has been looking at syndactyly (fused feet) and loss of limbs in frogs. He believes these problems are evidence of an ill environment, assuming toxins in the environment cause these developmental abnormalities. He explains that because of their different life stages and close association with watery environments, amphibians are “supersubject” to even the slightest variations in pH and overall composition of their aquatic environments. Because of their remarkable sensitivity, individual and populational amphibian health are good indicators of the health of the environments in which they live. Museum specimens can be examined for anomalies and used as bio-indicators in index environmental perturbations.

Such work has been done using museum samples of frogs from Kenya before and after colonization by Europeans. Two species of puddle frogs (of the genus Phrnobatrachus) from the Kinangop Plateau are well represented in the British Museum. They were collected prior to the 1930’s at a time when the area was well forested. Since then much deforestation, agricultural development, and pesticide introduction have taken place. Drewes plans to visit Kinangop Plateau, collect samples of frogs, look for developmental anomalies, and assess the effects of colonization and subsequent development on this area by comparing new samples with the older ones.

Drewes is also responsible for describing new species of frogs from central Africa. His latest frog, found in the Serengeti, which has yet to be given a name, belongs to the genus Hyperolius. And as Drewes so eloquently points out: Before we save them we’ve got to know who they are! There are many species in remote areas that have yet to be described. Without such descriptions, organisms may be dying off (as the result of human expansion and other factors) that we might never have known existed.

Some of the most remote areas on the planet are the deepest oceans. Since most of the planet is covered in ocean and other waterways, no discussion of the creatures of the Earth would be complete without addressing fish. About 25,000 species of fish have so far been described. The Department of Ichthyology collection houses half of the world’s known fish species (12,000), represented by about 2 million specimens.

Some of the strongest holdings, according to collections manager Dave Catania, are representative species from South America, notably the Amazon Basin. With all the destruction in this area relating to deforestation and subsequent run-off into the Amazon river, CAS’s collection is a vital resource form showing what once was the fauna of the Amazon. Using primarily their holdings of Tetras, Piranhas and their relatives (Characiformes) and Catfishes (Siluriformes), the Ichthyology department has been able to compare populations from the mid to late 1800s with those of today in the Amazon Basin to extrapolate the effects of development on these waterways.

Human activities can have devastating effects on natural environments. Although most damage is gradual, at times it can be immediate and devastating. Such was the case with the Exxon Valdez oil spill of 1989. Many fish, seabirds, marine mammals and marine invertebrates were wiped out either immediately by oil contamination or eventually as the oil choked ocean plants and thus disrupted the whole food web of the ocean. To assess the damage incurred, authorities called on CAS and its holdings of Alaskan fish to gather data on the distribution of certain species prior to the spill to compare with their status after the spill.

The California Academy of Sciences is involved in many aspects of conservation biology both directly and indirectly. Their role in conservation efforts is an ever increasing one. The wealth of information contained in each specimen at CAS (as in other natural history museum specimens) is a resource of great potential. Hopefully this article has provided at least a glimpse into the many ways in which natural history museum collections have been and continue to be used to, first, further our understanding of the diversity of life on the planet and, second, to strengthen our abilities to preserve this natural diversity.