Due to the considerable range of adaptive diversity that is demonstrated by amphibians and reptiles, no concise or specific compendium on approved methods in field research is practical or desirable. Rather, these guidelines are intended to advise the investigator, who may already be an authority on the biology of the species under study, on the current field techniques that are considered to be humane and effective in amphibian and reptile research. The researcher has the ultimate responsibility for the ethical and scientific validity of his/her work and for the methods that are employed. To those who adhere to the principles of careful field research, these guidelines will simply be a formal statement of precautions already in place.
Investigators have an obligation to identify and assess the consequences of their research activities on wild herptiles, populations and the environment. Whenever possible, action should be taken to avoid, alleviate or minimize any adverse effects. Research activities should include the collection of adequate samples to ensure valid research results, yet be balanced to minimize adverse effects. Investigators should always weigh potential gain in knowledge against the negative consequences of disturbance. Although short-term detrimental effects may result from research activities, research can ultimately yield long-term positive effects for the affected population.
Observer-related disturbance can be characterized in at least two ways. First, disturbances may create biases that affect both the gathering and analysis of data, if the actual process of measurement acts to alter the parameter being measured. Second, research activities might effect the status and well-being of the study subjects themselves. Both effects vary along a continuum from those that are overtly obvious to those that are subtle and difficult to detect. In addition, researchers should realize that disturbance also can occur to those species that are not under study.
Whether one is collecting study animals for eventual release or for museum preparation, the same humane considerations should apply. These animals should not be exposed to excessive or inappropriate handling, conspecific aggression, predation, temperature extremes, or undue suffering.
Each investigator should observe and pass on to students and co-workers a strict ethic of habitat conservation. Because many essential details of life history may remain unknown until a study is well along, collecting should always be conducted so as to leave the population and habitat as undisturbed as possible.
The permanent removal of more than 50% of the animals from any breeding or hibernation aggregation should be avoided, unless justified for very specific scientific reasons. Similarly, the collection of large numbers of females from any population for destructive sampling should be avoided. When permanent, destructive human alteration of a specific habitat is imminent (construction, water impoundment, etc.), the removal of entire populations may be justified. Systematists should investigate extant collections for suitable specimens before conducting any field work. If the purpose of an experiment is to alter behaviour, reproductive potential or survivability, the interference should be no more than is determined necessary by the investigator to accurately test the hypotheses under question.
Investigators must obtain and comply with all permits required for the capture, handling and collection of those amphibians and reptiles of the correct species and in the appropriate jurisdiction. In addition, they must be familiar with the current list of threatened and endangered species and must comply with all rules and regulations pertaining to these and all other categories of amphibians and reptiles.
Field research on amphibians and reptiles frequently involves the capture of live specimens for data recording, marking, temporary confinement, or relocation. Investigators should be familiar with herpetological traps and trapping techniques and should choose a trap type that is best suited to the species and type of study. In some cases, the use of a variety of traps is required to obtain an unbiased sample, particularly when secretive, nocturnal or inactive species are being targeted. Capture techniques should prevent or minimize injury or damage to the animal. Care should be exercised to avoid accidental capture of non-target species. Trapping and handling equipment should be routinely inspected and maintained in good working order. At the end of each collecting period traps should be properly closed or removed.
Amphibians and reptiles are sensitive to heat, cold, dehydration, energy deprivation and stress, and investigators must make every effort to avoid trap deaths from causes such as exposure, drowning, shock, and desiccation. Animals should not be left in traps longer than is absolutely necessary, although this may vary with the species, weather, objectives of the study, and trap type. In general, traps should be checked at least once daily. Traps should be shaded or positioned to avoid exposure to direct sunlight and care should be taken to reduce predation in pitfall traps. Where possible, trapping should be avoided when weather conditions threaten the survival of trapped animals. Pitfall traps set during extremely dry periods should have some moisture provided in order to prevent desiccation of captured amphibians.
In some instances, research may necessitate the judicious collection and preservation of specimens in the field. This may be done to provide information on species identification, genetics, population structure and dynamics, comparative anatomy and physiology, evolutionary relationships, behaviour, parasites and diseases, economic factors, geographic and microhabitat distributions, and ecology in natural or disturbed habitats. The knowledge that results from these studies may be applicable to other biological sciences and may help to facilitate decisions involving management policies for all species, whether endangered or economically important, for the conservation of habitats, ecosystem analysis, pest and disease control, retrospective studies and predator control.
Many specimens removed from the field are used collaboratively and deposited in the collections of natural history museums or biological data banks for future studies. Museum collections are curated repositories for whole specimens and their parts, whereas biological banks are collections of histologically or cryobionically preserved organs, tissues (including live cultures), cells (including sperm and ova) or embryos. Both kinds of repositories allow qualified researchers access to study collections. It is strongly recommended that, when appropriate, voucher specimens and other biological samples should be retained at the conclusion of field investigations, so that they will be available for use by future investigators. The collection of samples for museum preparation from natural populations is critical to:
Communication with researchers in other jurisdictions is recommended in order to maximize the use of and information gathered from biological samples.
Humane kill trapping methods are those that kill the animal instantly while avoiding damage to the body parts that are required for the investigation.
The nature of restraint will depend upon the procedure and the species involved. Restraint techniques can range from confinement in an enclosure, through various types of physical restriction, to chemical immobilization. Any decision to use physical or chemical restraint in a research project should be based upon an understanding of the behavioural and physical characteristics of the species to be restrained, the field conditions under which the procedure will occur, the knowledge and skill of those persons handling the animals, the goals of the investigation, and the availability of appropriate equipment and facilities. Investigators must use the least restraint that is necessary to do the job in a humane and effective manner, with the least stress to the animal.
Because amphibians or reptiles, especially venomous species (including those with toxic skin secretions), may be capable of inflicting skin irritation or serious injury to those handling them, some form of restraint is usually required . The well-being of the animal under study is of paramount importance and it must be emphasized that improper restraint, especially of frightened or stressed animals, can lead to major physiological disturbances. In addition, the capture of some species of animals may alter their behaviour and cause death or predispose to predation.
Many species of amphibians and reptiles are intolerant of physical restraint and in some cases there is potential for injury to animal or handler. Investigators should not allow unsupervised, inexperienced persons to handle any animal species until adequately trained to restrain, manipulate and release the animals properly. The researcher should consult the current literature and seek the advice of experienced professionals before handling an unfamiliar species.
The following are general guidelines that must be considered when a researcher restrains a reptile or amphibian.
Most amphibians and reptiles are relatively small and slow moving, and can be restrained by hand or in a net. However, many small species are easily injured if the handler uses excessive force. Tail autotomy (tail shedding) can occur in most lizards if they are restrained by the tail. Although this is not a serious injury, it will influence future growth and reproduction by depriving the animal of fat stores as well as the integrity of the specimen. Tail loss may also affect the behaviour of the animal.
Because some reptiles may struggle excessively when manually restrained, the use of nets, hooks, tongs or handling bags may be required to reduce injury.
Venomous snakes(e.g., rattlesnakes) and some large turtles are potentially dangerous and require special methods of restraint. Adherence to the following general guidelines is recommended when working with hazardous reptiles:
Prolonged distressful restraint should not be occur. In some cases, it may be advisable to utilize general anaesthesia for restraint in the field. If so, the anaesthetic chosen should be one that permits a rapid return to a normal physiological and behavioural state and the animal should be monitored until complete recovery occurs. The unpredictable nature and prolonged recovery times that are associated with the use of some anaesthetic agents in reptiles and amphibians may negate their use under field conditions. Because of this uncertainty, some minor procedures may be less traumatic and deleterious when performed quickly without anaesthetics by experienced personnel. The pain perception of these species is poorly understood. What causes pain and distress to a mammal may not have comparable effects on a reptile or amphibian; however, procedures should be performed under human and ethical conditions. Consultation with an experienced herptile scientist or veterinarian is required to choose the appropriate agents and to establish experimental protocols. Many chemicals used for restraint or immobilization of amphibians or reptiles also have the potential for deleterious effects on humans.
Where possible, investigators should assess the effects of immobilization chemicals and procedures on captive individuals before incorporating them into field studies.