|Bringing Science Back to the Conservation of the
ALEJANDRO RODR´IGUEZ,∗§ JAVIER CALZADA,† ELOY REVILLA,∗ JOSE´ VICENTE LO´ PEZ-BAO,‡ AND FRANCISCO PALOMARES∗
∗ Department of Conservation Biology, Estacio´n Biolo´gica de Don˜ana—CSIC, Ame´rico Vespucio s/n, Isla de la Cartuja, 41092 Sevilla, Spain
†Departamento de Biolog´ıa Ambiental y Salud Pu´blica, Universidad de Huelva, Avda Fuerzas Armadas s/n, 21071 Huelva, Spain
‡Grimso¨ Wildlife Research Station, Department of Ecology, Swedish University of Agricultural Sciences—SLU, SE-73091
Palomares et al. (2011) highlighted 4 factors associated with the reduced effectiveness of efforts to conserve Iberian lynx (Lynx pardinus) during the last 25 years: conservation measures have not been applied over large extents, few resources have been dedicated to scientific monitoring of the effectiveness of conservation actions, conservation efforts were implemented discontinuously, and practitioners have limited confidence in scientific knowledge. The authors of Simo´n et al. (2012) are mem- bers of the largest team currently managing Iberian lynx, and they contend that the trends in lynx abundance re- ported in Palomares et al. (2011) overlook that there have been substantial increases in the number of lynx over the last decade, that managed areas are large enough to sus- tain the species, that monitoring suggests management has increased lynx abundance, and that management, es- pecially under a consecutive set of projects funded by the European Union (LIFE) for the conservation of Iberian lynx in Andalusia, is long-lasting. We disagree and argue that available evidence, including that summarized by Simo´n et al., supports our position.
Simo´n et al. report that the areas occupied by the 2 remaining populations of Iberian lynx and total abun- dance of lynx increased by a factor of 2.5 from 2002 to 2011. This increase does not affect the evidence of long-term decline of Iberian lynx. Palomares et al. (2011) estimated that the 2 current Iberian lynx populations oc- cupied 19,800 km2 in 1955. On the basis of this estimate, range loss in 2005 was 93.9%, whereas on the basis of data provided by Simo´n et al., estimated range loss in 2010 was 96.4%. The recent expansion of lynx range (410 km2 from 2002 to 2010 [Simo´n et al.]) would be remarkable if the past lynx range had been smaller than previously re-
ported by Rodr´ıguez and Delibes (1992, 2002). Simo´n et al. suggest that Rodr´ıguez and Delibes (1992, 2002) over- estimated the area occupied by lynx in the past. Simo´n et al. argue these retrospective estimates were obtained from indirect methods, but they ignore that the estimates were derived from a systematic field survey in which sampling effort was consistent throughout the potential range of lynx and, therefore, results were spatially unbi- ased (Rodr´ıguez & Delibes 2002). In contrast, estimates of the past distribution of Iberian lynx presented by Gil- S´anchez and McCain (2011) relied mostly on specimens deposited in zoological collections and, hence, mainly reflect the areas scientists visited to collect samples of Iberian lynx.
Habitat management before natural or assisted recol- onization is rarely applied to large areas. Simo´n et al. recognize that most conservation efforts were concen- trated in the 1832 km2 already occupied by the Iberian lynx. We acknowledge that focusing habitat management on occupied areas may increase the number of reproduc- tive females and, therefore, the probability of long-term population persistence (Palomares et al. 2011). As car- rying capacity is approached, improving habitat quality on the edges of lynx habitat in Sierra Morena or in the interior of the Don˜ana National Park would allow more dispersers to establish territories and breed, and fewer dispersers would move into adjacent low-quality habitat. There have been recent reintroductions in eastern Sierra Morena (Simo´n et al.), and the European Union LIFE con- servation project, which commenced at the end of 2011 (see Table 1 in Simo´n et al.), aims to fund conservation of Iberian lynx in 5 regions across the Iberian peninsula. Concentrating available resources to increase the area
§Address for correspondence: email email@example.com
Paper submitted October 27, 2012; revised manuscript accepted March 21, 2012.
of breeding habitat, or creating a new, large area of lynx habitat, could be equally or more efficient than creating a large number of comparatively small and isolated habitat patches. In particular, habitat management over relatively large areas has not been undertaken outside Andalusia. Because mean time to extinction increases quickly as car- rying capacity increases (Palomares et al. 2011), a small number of relatively large lynx populations may be the best strategy (McCarthy et al. 2005), but we believe be- fore multiple reintroduction attempts are embarked on, models and data should be used to determine the optimal number of populations to be established or maintained.
The link between the inefficiency of Iberian lynx con- servation measures and a lack of scientific monitoring was identified more than a decade ago (Rodr´ıguez et al.
2000). Simo´n et al. argue that the Iberian lynx LIFE project team conducts scientific monitoring because the team in- cludes scientists who evaluate management actions, the conservation programs are reviewed by an external sci- entific panel, and the populations of lynx and their prey (the European rabbit [Oryctolagus cuniculus]) are mon- itored with standardized techniques. Monitoring should examine the extent to which the change one observes in a given behavioral or demographic parameter in the Iberian lynx can be attributed to one or more conserva- tion actions. Estimating abundances of lynx and rabbits (Garrote et al. 2011; Gil-S´anchez et al. 2011) with meth- ods such as camera trapping and counting rabbits in lin- ear transects, respectively, will allow data collected over time to be compared. But use of such methods does not directly address the more important question of whether changes in lynx abundance are the result of previous management efforts.
Simo´n et al. seem to assume that increases in abun- dance or number of populations of lynx or rabbits are mostly a consequence of management, but such relations may be correlative. For example, during the last decade many lynx emigrated from and started to breed outside Don˜ana National Park. In other words, natural coloniza- tion occurred first, breeding females were discovered later (because areas outside the park were not monitored until lynx were occasionally detected), and management was eventually applied to colonized areas. We question whether such expansion could be attributed to manage- ment.
Likewise Simo´n et al. report significant increases in rabbit abundance in some areas but, as pointed out by Palomares et al. (2011), it is unclear whether these increases were a response to management or largely to extrinsic factors (e.g., higher resistance to viral dis- eases or reduced mortality attributed to other predators), whether some measures were more efficient than others, or whether particular measures will reliably increase rab- bit abundance elsewhere. Nevertheless, the short-term assessment of effects of supplementary feeding on lynx behavior and demography by Lo´pez-Bao and co-workers
is a recent example of monitoring of the efficiency of a specific conservation measure, perhaps the only case in the history of Iberian lynx conservation. In this case, lynx responses (Lo´pez-Bao et al. 2008, 2010) and some of the mechanisms involved in their responses (Lo´pez-Bao et al.
2009, 2011) were investigated.
Simo´n et al. conclude that efforts to conserve the Iberian lynx have been consistent because funding for conservation projects has been continuous since 1994. However, the actions implemented, the locations where they were applied, and funding of each action in each area often varied from one 5-year LIFE project to the next. As a result, it is difficult to assess the efficacy of a given conservation action (Lo´pez-Bao et al. 2010). Also, actions that are expected to be beneficial only in the long term were interrupted before they could have a measurable effect. For example, a plan to increase the carrying capacity of the core area of Don˜ana National Park for breeding lynx was initiated in 2004 under the auspices of the Iberian lynx LIFE project team. Although preliminary results were promising in terms of retention of breeding adults (Lo´pez-Bao et al. 2008, 2010), actions such as supplementary feeding of lynx or rabbit restock- ing in predator-proof enclosures were discontinued 3 years later. Three years may be too short a period to ex- pect definitive results or even to generate sufficient data on which to base decisions about the effectiveness of a specific plan. For example, although food availability in- creased, general lynx scarcity in the region resulted in lit- tle immigration and reduced opportunities for dispersers to establish territories in managed habitat (Lo´pez-Bao et al. 2010).
Table 1 in Simo´n et al. shows the reliance of con- servation of Iberian lynx on external funding. Although regional governments execute environmental policies, including species conservation, on average European Union funds made up 68.3% of the total cost of the 27 projects (93%) reported on in Simo´n et al. (LIFE Nature
2012). Dependence on EU funding makes continuity of conservation action even less likely, especially during pe- riods of economic uncertainty. Moreover, regional recov- ery plans were made mandatory by a 1990 law, but it took 13–21 years to approve the plans in 3 autonomous regions, and 2 other regions have not approved them yet. Limited funding and marked slowness in establishing spe- cific regulations suggest there is room for improvement in the resolution with which regional governments act regarding Iberian lynx conservation.
Until 2008 managers and professional researchers co- operated, and scientific knowledge guided management, especially in the Don˜ana population of lynx. Since 2002 scientists who are members of the Iberian lynx LIFE project team have documented variation in lynx and rab- bit abundances, which is necessary but not sufficient to evaluate implemented management actions on the ba- sis of sound science. Data from scientific monitoring of
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specific conservation actions will inform decisions on how to efficiently apply the relatively scarce economic resources available to maintain Iberian lynx in areas they currently occupy and to increase the probability of recol- onization of currently unoccupied areas.
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