Abstract
The white-lipped peccary is a social ungulate that forms the largest groups documented for any other ungulate species living in tropical forests. White-lipped peccaries have become increasingly rare in Mexico and Central America in the last 50 years. Here I suggest some management actions for conservation of this endangered species in the Calakmul region based on a synthesis of ecological and social data coming mainly from a two-years' field study conducted in the Calakmul Biosphere Reserve (CBR) and three human communities
Introduction
The white-lipped peccary (

Individual white-lipped peccary (
Despite this reduction of the range, until 2008 the species has not been classified in the national list of endangered species (NOM-Norma Oficial Mexicana de Especies en Peligro) issued by the Environmental Ministry of the Mexican Government (SEMARNAT), and sport hunting is still allowed in Campeche and Quintana Roo states under the official scheme of Conservation and Management Units (UMA for its Spanish initials). The current situation is even worse when we consider that subsistence hunting [5–8], and forest fragmentation are affecting this species outside the protected areas without a conservation plan at any regional or national scale.
The white-lipped peccary is an unusual social ungulate that lives in closed habitats while forming large and cohesive groups, generally from 10 to 300 individuals, but there are historic reports of groups larger than one thousand animals [9]. Usually the white-lipped peccary travels long distances in non-predictable movements, but evidence of seasonal movements have been found for some places; however these movements are inside large home ranges [10, 11]. In other areas its presence is episodic and unpredictable [12]. The white-lipped peccary likes to wallow in muddy soils around water ponds and rivers, especially during the dry season. Peccaries are mainly frugivorous and can eat hard nuts not consumed by other species, e.g.,
Here I present a synthesis of ecological data on the white-lipped peccary and human social data obtained in the Calakmul Biosphere Reserve (CBR hereafter) and three adjacent communal lands (
Study Area

Localization of the Calakmul Biosphere Reserve (in dark gray) a study areas (white oval) in Mexico (light gray).
According to Köppen (modified by Garcia [19]), the Calakmul climate is warm and sub-humid (Aw), with a mean annual temperature of 24.6° C. There is seasonal rainfall, mainly in summer and early fall, with an annual average of 1,076.2 mm. The water in the area is obtained through precipitation since there is no a permanent river system. Most of the rainfall percolates through the limestone, but some drains superficially and stores in ponds. These ponds constitute the only source of water for wildlife through the dry season. There are four major forest associations [20], the Medium Sub-Perennial Forest (Medium), the Low-Flooded Forest (Flooded), which gets seasonally inundated after two to three months of heavy rains, and the Medium and Low Semi-Deciduous Forests, which both can be classified as dry forest (Dry).
Despite the presence of some jaguar hunters, gum tappers, and archeological looters, this region has remained almost undisturbed since the Mayans abandoned it 1,100 years ago. In the 1970s when the Mexican government encouraged the colonization of the “last frontier” in Mexico, the tropical forests of the humid and semi-humid tropics, such as Calakmul and other parts of Mexico, received a large influx of people from Mexico's central and southern states. This colonization process brought environmental changes to the region, and a municipality that presently includes 114 human settlements (
Methods and background information
White-lipped peccary capture, radio-telemetry, home range and habitat use
With the assistance of two persons, a total of 17 white-lipped peccaries from four groups were captured during the 2005 dry season and fitted with radio transmitters (Telonics, Inc.). Details may be seen in [16]. Groups were monitored using the homing method [25] that consisted of locating the groups from the only existing high points, the two Mayan temples of the Calakmul archeological city, and then walking towards the group. Using the homing method I collected 70% of the home range fixes as GPS points, while the other 30% were obtained through radio-telemetry triangulation from temporal points, and in some rare occasions from the highest points (Mayan temples and hills) [16]. Home range sizes were estimated for each group by the fixed-kernel, adaptive-kernel, and minimum-convex-polygon (MCP) methods [26]. Details may be seen in [16]. The four groups were monitored for different periods of time during the 18 months that encompassed the study time. The groups were identified as the Red, Blue, Green, and Yellow groups.
To estimate habitat preferences for each group, I recorded the forest type where the group was observed, and thereafter at 15-minute intervals while in contact with the group. I never attempted to estimate forest type based on the radio-telemetry locations; all forest type use data was obtained by direct observations of the four groups. I used compositional analysis [27] as the main method for contrasting the use of habitat types by white-lipped peccary groups vs. habitat availability (see details in [16]).
During the 18 months of the study I encountered the groups on 203 days. I maintained contact with the groups from 10 to 17 months (see details in [16]). In accordance with Seaman and Powell [28] and Seaman et al. [29], I considered the 95% fixed-kernel estimates to best represent the home range of the groups for their respective periods of time (Fig. 3). With 95% fixed-kernel, the Blue group had the largest home range (97.5 km2) followed by the Green group (82.4 km2). Groups shared the same space almost completely during the dry season of 2005 with a 91.7% degree of overlap for the four groups combined (Fig. 4). During the rainy season of 2005, the Blue, Green and Yellow groups traveled to different areas to the north whereas the Red group stayed in the dry-season area (Fig. 5). The degree of overlap dropped to 34.5% for the rainy season of 2005 for all the groups (see details in [16]).

All-seasons fixed kernel (95% home range represented by the total area of each color, and 50 % by the circles inside, respectively) home ranges for the four groups of white-lipped peccary in the Calakmul Biosphere Reserve, Campeche, Mexico (taken from [16]).

Fixed kernel home range estimation for the dry season of 2005 for the four groups of white-lipped peccary in the Calakmul Biosphere Reserve, Campeche, Mexico (taken from [16]).

Fixed-kernel home range estimation for the rainy season of 2005 for the four groups of white-lipped peccaries in the Calakmul Biosphere Reserve, Campeche, Mexico (taken from [16]).
Compositional analysis for Johnson's [30] third-order selection (MCP home ranges vs. group localizations) showed that inside their home ranges all groups significantly preferred ponds and medium forest and avoided the dry forest. I performed an additional analysis taking away observations in ponds; the results consistently showed that all white-lipped peccary groups significantly preferred medium forest and avoided dry forest. Flooded forest was also very important for the four groups and for the Green group was ranked even above medium forest and just below ponds (see details in [16]).
Group sizes, breeding season and hunting patterns
Group sizes and breeding season of white-lipped peccaries were recorded during field surveys at five sites. Three sites were the
Data about subsistence and sport hunting events in the three
The sizes of 24 white-lipped peccary groups were recorded at the four sites from 2001 to 2007. Ten observations were obtained from
From 2001 to 2007, I recorded 19 birth events in at least 17 different groups from all the study sites except from one of the
I recorded 21 hunting events during the study period. These events were performed by subsistence hunters (19) in the three
Ecological density
I estimated white-lipped peccary density for the CBR based on a minimum convex polygon constructed from location fixes obtained while searching the area several times every month (from the period of 2005–2006) while trying to make contact with the four radio-marked groups (named Red, Blue, Green and Yellow) during a 10-month period. I favored this estimate because from March to December 2005 I had continuous contact with the four groups and had precise counts of their size. Additionally, during intense field work in these 10 months, I did not see any white-lipped peccary sign that could not be attributed to the four groups. Every time I encountered a white-lipped peccary sign I confirmed the identity of the group traveling there by using the radio-marked animals in each group. Group observations for more than 200 days confirmed the high fidelity of marked individuals to their respective groups (see details in [17]). Additionally, I estimated the number of individuals and groups existing in the southern area of the CBR by extrapolating these estimates to a larger polygon that included the study area and almost all the southern area of the CBR, with an exception of a 5 km buffer from the border with the

Area used and shared by four groups where density was estimated (encircled by light green line) and area where density was extrapolated (encircled by the blue line) of white-lipped peccaries in the southern area of the Calakmul Biosphere Reserve, Campeche, Mexico (taken from [17]).
The entire area where only the four radio-marked groups lived during a 10-month period of continuous radio contact was estimated to be 236.7 km2 (Fig 6). The sizes of the four groups were 31, 25, 25, and 20 at the beginning of the radio-telemetry study for a total of 101 white-lipped peccaries. Therefore, the estimated density was 0.43 / km2, or one white-lipped peccary/2.34 km2. I used this density estimate to calculate white-lipped peccary density on the whole southern area of the Calakmul Biosphere Reserve. For the extrapolation exercise, I defined a larger area that encompassed almost all the southern area of the CBR except a buffer of 5 km between the reserve and the
Conservation analysis
Data on home range, habitat use, relative abundance, group size, hunting pattern, density, and range behavior were integrated and analyzed under the spatial and social perspectives of the CBR and the three
Results
Current status of the species outside the Calakmul Biosphere Reserve
The situation of white-lipped peccary population outside the CBR is worrisome due to several facts indicating that the species is not doing well outside the protected area. For example, groups were bigger in the protected area than in the
The large home range of groups as determined in the CBR indicates that this species needs large forested areas to sustain viable populations. It was also shown that the species often visits water bodies and that the preferred habitats were the medium semi-perennial forest and the low-flooded forest while the dry forest was always avoided. These conditions can be found in the
Projections of population density
I extrapolate the density estimation obtained from the CBR into the forested area in the
Discussion
Among the main results, I found that in the Calakmul region group sizes never exceeded 35 individuals, and that they have one of the largest reported home ranges. White-lipped peccaries substantially increased their home ranges when the rainy season arrived in the CBR, suggesting that water availability plays an important role in determining movements of this species.
Habitat use of white-lipped peccaries showed that a forest having a high density of ponds with a combination of semi-perennial and low-flooded forests are the preferred habitats for this species. Water availability could be the factor most important for groups of white-lipped peccaries in any given site. In this study, water access was the driving force behind long movements, and this determined extension of home ranges during the dry season. Empirical observations showed also that white-lipped peccaries prefer areas where the two forest types are mixed and that they avoid large patches of single-forest types [16]. Therefore, preserving the mosaic of vegetation and existing water bodies is one of the very important actions for conservation of this species in the region.
If we compare white-lipped peccary populations in the CBR to populations in human-use areas where hunting pressure exists, this study presents evidence that the populations in the human-dominated areas are not doing well. When contrasting the size of groups in the CBR and in communal forests where hunting pressure exists, I found that groups were bigger in the CBR than in the hunted sites, which suggests that this species is being affected by human factors in the communal forests. Additionally, hunting activities (either subsistence or sport) were practiced in the dry season, which is also the breeding season for the species, when they are very vulnerable to hunting due to their behavior of visiting ponds. Hunting during the dry season is one of the main threats to the species in communal forests and can have disastrous consequences for the populations outside the CBR. Additionally, sport hunters are allowed to hunt this species during the last two months of the dry season (April–May), a time of potential maximum stress on white-lipped peccary groups. Along the same lines, hunting a large proportion of any group will have behavior consequences for the rest of the animals, making them vulnerable to high predation levels or limiting the ability to reach feeding/drinking areas, since only some of the animals may know the locations. The social behavior of the group must be respected and preserved in any management activity like sport or subsistence hunting.
Implications for conservation
According to these results, to conserve white-lipped peccary populations in the CBR and the communities around it we will need to preserve large areas of tropical forest.
To conserve white-lipped peccaries in northern Central America it will be necessary to preserve intact this piece of the Maya forest and the attributes that allow this species to survive in it. Conservation measures will likely include effective protection against hunting, no further road development to maintain the isolation of the area, maintaining the availability of ponds and/or other sources of water, and the maintenance of a landscape composed of interspersed medium and flooded forests. Among active conservation measures would be to insure that white-lipped peccary groups have access to water sources (it might even be worthwhile to strategically locate artificial water containers for the extremely dry years like 2005 and 2006). Also, conserving large intact patches of forest would maintain white-lipped peccary populations on human-dominated landscapes if hunting pressure can be controlled [17].
Very important components of the landscape are the communal forests (
Conserving white-lipped peccaries in
For any conservation plan to be successful in such forests, it will have to be developed inside the communities with advice from outsiders, because rules applied by authorities in the city are usually ignored in the area, and there is no law enforcement in the region. Subsistence hunters, if willing, have many options to reduce the pressure on this species. One could be to agree to temporarily ban hunting of the species, at least during the dry season, to allow groups to have access to water during this vulnerable time of the year that is also the breeding time. Other measures that could be taken locally would be to decree a protected area to serve as a source of individuals for the hunting areas. For all these management/conservation actions, monitoring of success and impact will be essential, so residents need to work closely with NGOs, or with academic and governmental institutions that can provide training and capacity building on wildlife ecology and conservation issues.
White-lipped peccary groups in the Calakmul region inhabit a forest that lies in the northern extreme of the species' distribution and where conditions are sub-optimal for its survival. These conditions make this species vulnerable to hunting and other human-induced effects because of the low density and smaller group sizes occurring there. Additionally, the breeding season coincides with the time of the year when the peccaries become more vulnerable to hunting. It is a priority that the government institution in charge of sport hunting (Direccion General de Vida Silvestre), as well as other NGOs and academic institutions involved, consider banning the sport hunting of this species until more sound biological information is obtained, or allowing hunting only during the rainy season. Additionally, a very important action is to limit the number of individuals harvested from a group. As a preventive measure, no hunter should take more than 10% of any given group. Considering that the median group size in the
The future disappearance of white-lipped peccary in communal forests could have significant consequences for the ecological processes of these forests and for the remnant white-lipped peccary population in the CBR. Conservation of white-lipped peccaries only within a few large and well-protected reserves, like the CBR, will not represent the best scenario for the conservation of this species in México.
Footnotes
Acknowledgments
I thank E. Rojas-Flores, N. Arias, G. Arias, E. Gutierrez and S. Pérez-Cortez for invaluable fieldwork help. G. Tanner provided support for all the stages of this research. C. Chapman, S. Calme, S. Mandujano, S. Gallina, and J. Blaha improved greatly this paper with interesting comments. I am also grateful to two anonymous reviewers for useful comments on earlier drafts of this paper. M. Weber kindly provided radio-telemetry equipment. F. Durand-Siller, director of the Calakmul Biosphere Reserve, provided permits to do research in the area. C. Vidal, director of the INAH-Campeche, provided permits to work in the archeological city of Calakmul. Light-Hawk volunteers and Semarnat-Mexico provided a flight each to locate the groups. This study was possible thanks to the generosity of CONACYT-Mexico with a grant to R. Reyna-Hurtado 150332 for completion of PhD studies, and to the WCS-Research Fellowship Program and IdeaWild that provided the funds for the fieldwork and equipment. The handling of animals was performed under protocol authorized by the Direccion General de Vida Silvestre (Mexico) and IACUC permit #D594.
Appendix 1. Maximum estimated number of individuals and groups in the Ejidos and categorization of each,according to the size of the area,hunting pressure and connectivity with the CBR.
| Study Sites | Nuevo Becal Ejido | 20 de Noviembre Ejido | Xbonil Ejido | CBR |
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| Total Area | 520 km2 | 280 km2 | 500 km2 | 3509 km2 |
| Total area minus a 20 % (to account for land transformed). | 416 km2 | 224 km2 | 400 km2 | n/a |
| Connectivity with the CBR | Low | Inexistent | High | |
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| Relative abundance of white-lipped peccary obtained in 2001 (# of traces per km walked) | 0.05 | 0.02 | 0.20 | 0.22 |
| Maximum population estimated based on extrapolated density found on the CBR | 178 indiv. | 96 indiv. | 171 indiv. | 1493 indiv. |
| Maximum number of groups of white-lipped peccary (considering a median of 20 indiv./group in the |
9 | 5 | 9 | 58 |
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| Total human population | 350 | 343 | 618 | ——– |
| Proportion of hunters among adult men interviewed | 93 % | 62 % | 70 % | ——- |
| Average of people per household | 6.33 | 5.45 | 4.44 | ——- |
| Average distances in each hunting trip | 15.5 km | 10 km | 12.8 km | ——– |
| Occurrence of hunting trips | Every 28 days (from 4 to 90 days) | Every 91 days (from 3 to 360 days) | Every 25 days (from 3 to 120 days) | ——- |
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