Response to the Desert Tortoise Council Position Paper on the Massive Project Proposal
J.O. Juvik (jjuvik@hawaii.edu), R. Kiester (rkiester@gmail.com), and K. Nagy (kennagy@biology.ucla.edu)
Since writing the original Massive Project Proposal (see massivetortoise.org) and since having the pilot project funded we have received much valuable input from the broad desert tortoise community. The position paper written by the Desert Tortoise Council (Desert Tortoise Council Newsletter, Winter 2009) is part of that input. Here we wish to comment on their points.
Conservation of the desert tortoise (Gopherus agassizi), as of any organism, is done at the interface of science and policy. Science informs actions, but does not determine them. Scientific uncertainty is a major reason why work at the science/policy interface is so difficult. Decisions must be made and actions taken in the face of serious uncertainty. Shrader-Frechette and McCoy (1993) give an excellent discussion of these topics. Put another way, both the action of releasing head-started tortoises and the action of doing nothing have risks and the policy maker must balance these risks.
We take each paragraph of the DTC position paper in turn.
1. Introduction and background. This is a straightforward account of the background of desert tortoise conservation.
2. Head-starting background. Conveys some of the uncertainty surrounding desert tortoise head-starting.
3. Disease and food competition. The position paper wants a guarantee of disease free eggs. Although we believe that vertical transmission of mycoplasma does not occur, we propose to carefully screen head-started tortoises for all diseases many times before they are released. We plan to have at least 4 to 5 years to make sure baby tortoises are healthy. So our goal is to produce disease free juveniles that are to be released. Rideout (2010) has recently emphasized the role of errors in disease screening prior to releasing animals. Multiple tests through time as a tortoise matures will help reduce these errors, but we can never eliminate all of them. We believe this kind of screening gives a more practical goal to work towards.
The position paper is also concerned that released tortoises would compete for food with native tortoises and among themselves. We do not intend to release tortoises where there are native populations so competition with natives will not occur. Certainly competition will occur among the released tortoises themselves. We will have to take care that food is not a limiting factor in release sites.
4. Ethics. Here we are in the realm of pure policy. Science cannot inform this discussion very much. We would like to emphasize that there is a continuum of beliefs held by people on this issue. At one end someone from, say, PETA, would claim that a conservation action that results in a single death is unethical. At the other end, people who recognize that tortoises are mortal and that nearly all juveniles die in natural populations would claim that is ethical for a large proportion of introduced tortoises to die in the process of reestablishing a healthy population. Where any one person falls on this continuum is a very personal decision. It is not clear to us how a consensus could be reached on this issue although there is no question that the desert tortoise community must continue to debate it.
5. Genetics issues. The debate between adaptedness and adaptabilty is again about a continuum. This continuum can also be understood as the choice of the appropriate spatial scale for the interpretation of genetic variation in conservation action. The entire range of the desert tortoise is clearly too large, and a population on 10 hectares is too small. Is the genetic scale implied by the mapped recovery units appropriate? We are not sure. The position paper claims that our assumption that adaptability is important is not science. However, Fisher's Fundamental Theorem of Natural Selection is regarded as one of the cornerstones of evolutionary theory (see massivetortoise.org). There is no question that there is considerable uncertainty about the details of the application of this theorem in any particular case. So the real question is how to make policy decisions in the presence of uncertainty.
Note on use of the word “hypothesize.” We used the word in the more general sense, not in the strict sense of Neyman-Pearson hypothesis testing. Nonetheless it is worth noting that probabilistic hypotheses can be tested making the word “may” acquire a quantitative sense. The relationship between specific hypotheses and general (and sometimes stochastic) theories is well described in Ford (2000). The necessity of synthesizing hypotheses for policy is reviewed in Ford and Ishii (2001). Neyman-Pearson hypothesis testing is only a part of the scientific enterprise.
There have been field tests for a reptile introduction of the trade-off between adaptedness and adaptability by A. R. Templeton (Templeton et al., 2007). More genetically variable populations of introduced collared lizards do better than genetically more uniform populations. In his review of the Massive Project Templeton writes:
This issue of adaptiveness vs. adaptability has come up in two release projects I’ve been involved with, the collared lizards (which we talked about in Hawaii) and, more recently, the reintroduction of the wild ass in the Negev Desert in Israel. I have attached some reprints outlining our logic in these reintroductions. Concerning the collared lizards, I have attached a 1996 paper that outlined our strategy. The discussion starting on page 318 is especially relevant. As you will see, I come down on the side of adaptability. Basically, we can never be sure that the environments into which we re-introduce the animals are exactly like their historical environments, and moreover during this time of global climate change, the environments are likely to continue to change. Hence, adaptability is more important than adaptiveness, but you will see that we did not totally ignore the issue of adaptiveness.
6. Recovery plan and legal and regulatory issues. The newer recovery plan explicitly contains provisions for population augmentation. The Massive Project falls under this section of the plan. There are of course many legal and regulatory issues that must be addressed for this, or any, reintroduction plan to move forward. Our initial meetings with regulatory agencies in 2009 have made these issues clear and we believe that they can be solved.
7. Illegal releases and predator subsidy. We simply do not know if legal reintroductions will “encourage” illegal ones. This is an empirical question about human behavior. How one feels about the possibility in the absence of any study probably depends on their general view of human behavior (cynical vs. optimistic). Certainly the Massive Project will need to emphasize this issue and publicize the appropriate alternatives available to people who need to find homes for desert tortoises.
If reintroductions do end up subsidizing predators that then move to impact native populations, we will conclude that the Massive Project has backfired and not move forward with it. We are only interested in increasing the total number of desert tortoises in the Mojave Desert.
8. Location, location, location. We agree with the idea expressed in the position paper that release site identification should occur at the beginning of the pilot study. We have begun that process in discussions with landowners and stakeholders.
9. Priorities. Certainly we agree that the protection of natural populations and their habitats is the top priority. But we also believe that it is not the only priority and certainly not the only tool that should be used. We have learned from work on the Asian Turtle Crisis and on the ploughshare tortoise that using all available tools in an ecumenical, diverse strategy is the best overall strategy.
The current “Draft Revised Recovery Plan for the Mojave Population of the Desert Tortoise (Gopherus agassizii)” (2008) has two goals: 1.) Increase the number of tortoises in current populations in the Mojave and 2.) Expand their distribution into areas of their former range. Because of the nature of desert tortoise demographics, achievement of these goals in any reasonable timeframe leads the recovery plan to embrace the role of population augmentation as a part of any strategy of timely recovery actions. Unfortunately, the proposed recovery plan price tag of $50 million may be difficult to implement over the next few years in the current federal budgetary environment. The Massive Project is designed to support the augmentation component of the recovery plan by employing a novel, comparatively large-scale, low cost head-starting approach that simply scales-up from existing, scientifically proven head-starting protocols.
Ford, E.D. 2001. Scientific Method for Ecological Research. Cambridge University Press. 588 pp.
Ford, E.D. And H. Ishii. 2001. The method of synthesis in ecology. Oikos 93(1): 153-160.
Rideout, B. 2010. The Pitfalls of Using Test Results for Decision-Making in Conservation Programs. Thirty Fifth Annual Symposium of the Desert Tortoise Council Abstract.
Shrader-Frechette, K. and E.D. McCoy. 1993. Method in Ecology: Strategies for Conservation. Cambridge University Press. 344 pp.
Templeton, A.R., J. L. Neuwald, H. Brazeal, and R. J. Robertson. 2007. Restoring Demographic Processes in Translocated Populations: The case of Collared Lizards in the Missouri Ozarks using Prescribed Forest Fires. Israel Journal of Ecology and Evolution 53: 179–196.
March 12, 2009