Ethiopian Wolf Monitoring in the Bale Mountains from 2001-2004 Deborah Randall 1,2,3*, Lucy Tallents 1,2, Stuart Williams 1,2 and Claudio Sillero-Zubiri 1,2 1 Ethiopian Wolf Conservation Programme, PO Box 215, Robe, Bale, Ethiopia 2 Wildlife Conservation Research Unit, University of Oxford, The Recanati-Kaplan Centre, Tubney House, Tubney OX13 5QL, U.K. 3 Frankfurt Zoological Society - Ethiopia, PO Box 100003, Addis Ababa, Ethiopia *Email: deborah.a.randall@gmail.com Abstract The largest population of Ethiopian wolves, which exists in the Bale Mountains, has been monitored almost continuously by the Ethiopian Wolf Conservation Programme since 1983. In the present paper, we outline wolf monitoring activities in the Bale Mountains from 2001-2004 and provide an estimate of Ethiopian wolf population size for this period. We also discuss wolf monitoring practices based on a review of the long-term objectives of the EWCP monitoring programme. Between 2001 and 2004, as a response to a rabies outbreak, monitoring effort and spatial coverage increased substantially from previous years to include demographic and spatial data on 60 focal packs throughout the Bale massif and an estimated 300 to 350 adult and subadult wolves (> 1 year old). We present an overview of the EWCP s wolf monitoring objectives, review monitoring protocols and activities during this period and outline considerations for ongoing monitoring in the Bale Mountains. EWCP embraces the following monitoring objectives in Bale: (i) obtaining reliable, annual population estimates that enable the EWCP to monitor population trends over time; (ii) ensuring comparable estimates of wolf abundance between study areas and years; (iii) collecting detailed data on focal packs, including size, composition, territory configurations, and breeding success; (iv) detecting disease epidemics quickly should they occur, and (v) monitoring changes in genetic diversity. Introduction The Ethiopian wolf (Canis simensis) is a rare canid endemic to the highlands of Ethiopia (Sillero- Zubiri et al. this edition). They are listed as Endangered by the IUCN Red List (Sillero-Zubiri and Marino 2008) and restricted to only seven isolated mountain ranges in Ethiopia above 3,000 m a.s.l. (Marino 2003b). With a global population estimated at around 500 adult individuals, Ethiopian wolves are the rarest carnivore in Africa, and one of the rarest in the world (Sillero-Zubiri and Marino 2004). Ethiopian wolves are a social species, living in packs of 2-17 individuals but, unlike other pack-living canids, individuals forage alone for rodents (Sillero-Zubiri and Gottelli 1994, Walia-Special Edition on the Bale Mountains 28
# 1995a; Sillero-Zubiri et al. 2004, Sillero-Zubiri et al. this edition). As a result of their specialized feeding habits, Ethiopian wolves are restricted to those montane areas where suitable habitat supports an abundance of their primary prey species - diurnal rodents of the Afroalpine ecosystem (Sillero-Zubiri and Gottelli 1995a). Ethiopian wolves are territorial with packs maintaining discrete territories that tessellate to occupy all available habitat. In high density wolf areas (> 1 wolf/km 2 ), average pack size is six adults and yearlings and average territory size is 6 km 2 (Sillero-Zubiri and Gottelli 1995b). Dispersing floater females, comprising approximately 7% of the population, range solitarily over the territories of one or more packs (Sillero-Zubiri et al. 1996). History of the Ethiopian Wolf Monitoring Programme in the Bale Mountains The estimation of population size and monitoring of population trends is a critical part of the conservation and management of endangered species and has been a fundamental activity of the EWCP since its inception. The largest population of Ethiopian wolves is mostly found within the 2,200 km 2 Bale Mountains National Park (BMNP) in south-eastern Ethiopia. Here the population, which has been monitored almost continuously since 1983, is subjectively subdivided into eight linked subpopulations, some of which are continuous within the Afroalpine landscape (e.g. Sanetti, Chafa Delacha, Rafu, Tullu Deemtu and Central Peaks), others being well-defined by the lava walls and rocky peaks that demarcate corridors between them (e.g. Morebawa and Web Valley), and Gaysay Valley, which is more isolated montane grassland at the northern end of BMNP (Fig. 1). Ethiopia Bale Mountains Gaysay Valley (1) Wolf habitat 7 10' Wolf ranges indicated Park boundary Web Valley (10) 7 00' Morebawa (17) 0 N 10km Central Peaks (9) Raffu (5) Tullu Deemtu (2) 39 30' 39 40' 39 50' Sanetti Plateau (9) Chafa Delacha (7) 6 50' Figure 1. Wolf habitat in the Bale Mountains with eight study areas indicated. Numbers in brackets indicate the number of packs identified in each study area between 2001 and 2004. Walia-Special Edition on the Bale Mountains 29
Regular surveys of wolves were first undertaken in the early 1980s by the Bale Mountains Research Project (Hillman 1986). From 1987 to 1992, CSZ undertook detailed research on Ethiopian wolves in the Bale Mountains in four study areas; namely Web Valley, Sanetti Plateau, Tullu Deemtu and Gaysay Valley (Fig. 1, Sillero-Zubiri 1994). Monitoring of wolves in these areas has been continued since 1995 up to present by the Ethiopian Wolf Conservation Programme (EWCP) and, since 2001, the EWCP has expanded the monitoring programme to include all wolf range in the Bale massif as well as the six other wolf populations in Ethiopia (Ash 2001). The history of the EWCP monitoring programme in Bale is described in greater detail in Marino et al. (2006). Monitoring activities consist primarily of total counts in focal packs. The high densities that wolves attain in many areas, their diurnal habits, and conspicuous coats render them relatively easy to find and follow on foot or horseback in the open Afroalpine landscape. Packs are identified as groups of individuals with distinct compositions, maintaining discrete territories that have little overlap with adjoining territories, and using exclusive dens during the breeding season. New packs, whether newly formed by pack fission or previously undiscovered by the EWCP, are identified by the same criteria. Territory boundaries for individual packs are determined during focal follows of regular boundary patrols, identified as such by copious scent-marking and, often, active territorial defence by individual wolves and packs. Maps of territory boundaries are then digitized in ArcView software (Environmental Systems Research Institute, Redlands, California, U.S.A.) by pooling GIS data collected in the field for each pack over a given time period (typically a single breeding season). Individual recognition during the early years of the monitoring programme was assisted by ear-tags, radio-collars, and coat patterns (Sillero-Zubiri 1994; Sillero-Zubiri and Gottelli 1994, 1995b; Sillero-Zubiri 1996). From 1996 onwards individual recognition was more difficult due to the absence of artificial marks (previously ear-tagged animals died or disappeared and no new animals were marked until 2003) and, more recently, a larger number of focal packs under observation. Population monitoring has thus been based on complete enumeration of animals in focal packs (i.e. records were kept of all wolves seen around the den, or during social greetings and patrols, until no new individuals were observed). Sex and age classes have been assigned to wolves according to the following categories: adults (> 2 years), sub-adults or yearlings (1-2 years), and pups (0-12 months), male, female, unknown (unknown age and/or sex). In addition to the continuous monitoring of focal packs, the EWCP conducts monthly transect counts in the Sanetti Plateau (since 1985) and Web Valley (since 1989) (Marino et al. 2006). From these, indices of abundance calculated from repeated transects have been used to analyze trends in these two subpopulations areas. See Marino et al. (2006) for a more detailed description of this method and the results it has produced. Walia-Special Edition on the Bale Mountains 30
Monitoring Activities the Bale Mountains from 2001-2004 From 2001-2004, the effort and spatial coverage of the EWCP monitoring programme in the Bale Mountains increased substantially from previous years, largely in response to a rabies outbreak and subsequent vaccination of wolves (Randall et al. 2004; Knobel et al. 2008). During this time, the number of monitoring personnel also increased from only two staff in 2001 and less than 100 person days to nine staff in 2004 and over 1,000 person days expended in the field collecting a substantial amount of data on pack size, composition, and distribution over a wider area (Fig. 2). Monitoring effort was unevenly distributed throughout the Bale massif with the most effort concentrated in the Web Valley, Sanetti Plateau, and Morebawa areas in 2003 and 2004 (Fig. 1). During these years monitoring in the Web Valley was particularly high in response to the rabies outbreak in that area (August 2003 to January 2004, Randall et al. 2004) and monitoring in the Sanetti Plateau and Morebawa areas focused on assessing the survival of wolves captured and vaccinated during the emergency vaccination programme (Knobel et al. 2008). Figure 2. Monitoring effort in eight study areas of the Bale Mountains from 2001 to 2004. Numbers above bars indicate the number of monitoring personnel employed by the EWCP each year. The monitoring methods used followed those described above for determination of pack boundaries and complete enumeration of unmarked individuals in focal packs based on sex and age assignment. However, a certain level of individual recognition was also possible following the vaccination intervention in 2003 (Randall et al. 2004; Knobel et al. 2008) when unique combinations of colour-coded ear tags were put on a number of wolves in three study areas (Web Valley, Morebawa, and Sanetti Plateau). Walia-Special Edition on the Bale Mountains 31
Ethiopian Wolf Population Size in the Bale Mountains from 2001-2004 Previous to this study, the most recent estimate of the total Ethiopian wolf population size in the Bale Mountains was 250 individuals (Sillero-Zubiri et al. 2000). This estimate, made in 2000 at the Ethiopian Wolf Conservation Strategy Workshop held at the headquarters of the BMNP, was based on extrapolation of known wolf densities in optimal, good, and marginal habitat categories (sensu Gottelli and Sillero-Zubiri 1992; Sillero-Zubiri 1994; Marino 2003a) to the extent and types of habitat available in the Bale massif (Sillero-Zubiri et al. 2000). Habitat categories throughout wolf range were assigned on the basis of quantitative data showing correlations between rodent density, wolf abundance and vegetation height, as described by Gottelli and Sillero-Zubiri (1992) and later applied by Marino (2003b) to estimate population sizes in other wolf ranges. From 2001-2004, a total of 60 packs were monitored in the Bale Mountains with an estimated 328 adult and subadult wolves (> 1 year) in eight study areas (Table 1). Twenty-three floater females were suspected based on ranging behaviour spanning more than one pack territory. However, floater females are difficult to identify and monitor without individual identification, therefore their number was estimated as 7% of the total population in each study area based on previous estimates of the relative number of floaters in the population (Sillero-Zubiri et al. 1996). Wolf numbers in the Web Valley presented in Table 1 are estimated before the rabies outbreak in late 2003, which reduced the population from 68 adults and yearlings to approximately 21 individuals in early 2004. Thus, there were probably around 350 adult and subadult wolves in the Bale Mountains before the rabies outbreak in late 2003, and probably around 300 wolves immediately after the outbreak. Therefore, we conclude that there were approximately 300 to 350 wolves in the Bale Mountains between 2001 and 2004 but, since a number of packs were probably not yet identified or monitored, total population size is likely to have been larger than 350 wolves. Pups were excluded from our estimate of population size, ensuring comparability with previous estimates (Sillero-Zubiri and Gottelli 1995b; Marino et al. 2006). Walia-Special Edition on the Bale Mountains 32
Table 1. Packs monitored in the Bale Mountains between 2001-04. ID s refer to the territory location in Figure 3. Study area ID Pack name Pack size Study area ID Pack name Pack size Web Valley 1 Alando 4 Sanetti 29 Badagasa 10 2 Darkeena 9 30 Batu 8 3 Doda 7 31 BBC 9 4 Hybrid 2 32 Bilisa 6 5 Kotera 10 33 Garba Guracha 11 6 Megity 8 34 Lencha 6 7 Mulamu 9 35 Nyala 6 8 Sodota 2 36 Quarry 6 9 Tarrura 10 37 Sulula 5 10 Wolla 2 Floaters 5 Floaters 5 TOTAL 72 TOTAL 68 Central Peaks 38 Buyamo 4 Gaysay 11 Gaysay 3 39 Dandy 6 40 Kara 4 41 Kurumesa 3 Morebawa 12 Ariye 3 42 Lucky 5 13 Burra 5 43 Saletti 3 14 Chalaka 3 44 Shaya 7 15 Chokisa 4 45 Wasama 5 16 Duna 8 46 Worgona 4 17 Fotura 2 Floaters 3 18 Fulbana 8 TOTAL 44 19 Genale 6 20 Gurati 6 Chafa Delacha 52 Abala 8 21 Haro Bachay 4 53 Agicho 6 22 Huke 5 54 Bedessa 6 23 Kumbuta 6 55 Konteh 8 24 Leliso 5 56 Likita 3 25 Osole 6 57 Shefa 8 26 Rogicha 6 58 Shiwwa 4 27 Waota 6 Floaters 3 28 Weshema 3 TOTAL 46 Floaters 6 TOTAL 92 Tullu Deemtu 59 Tullu Deemtu 1 3 60 Tullu Deemtu 2 2 Raffu 47 Chufo 3 TOTAL 5 48 Dimma 2 49 Kolela 6 Total packs 328 50 Onburi 4 Total floaters 23 51 Raffu 5 Floaters 1 Grand Total 351 TOTAL 21 Pack sizes determined from monitoring during the 2002-2003 breeding season (ie. before the rabies outbreak in late 2003) Pack sizes determined from monitoring during the 2003-2004 breeding season. Pack sizes are estimated from fewer data collected between late 2003 and early 2005. Territory boundaries in Fig. 3 are estimated as no spatial data were available. Figure 3 shows the distribution of known packs in the Bale massif from 2001 to 2004. Territory boundaries are depicted for Web Valley packs during the 2002-2003 breeding season (i.e. before the rabies epidemic in late 2003) and for the Sanetti Plateau and Morebawa packs during the Walia-Special Edition on the Bale Mountains 33
2003-2004 breeding season (after the vaccination intervention). Territory boundaries for other packs are based on fewer data, due to lower monitoring effort in those areas, collected between 2003 and early 2005. Wolf habitat Pack territory 11 Gaysay Valley 13 Morebawa 24 20 23 12 21 16 27 2 Web Valley 9 7 3 5 6 4 7 00' 1 10 8 19 Central Peaks 45 28 43 46 18 39 25 44 Sanetti 15 40 22 41 Plateau 38 17 35 Raffu 47 42 37 13 49 29 26 30 33 48 51 50 31 36 59 Tullu Deemtu 34 32 N 0 10km 39 40' 60 Chafa 53 Delacha 39 50' 52 55 54 57 56 58 Figure 3. Territory boundaries of known wolf packs in the Bale Mountains from 2001-2004. Territories in the Web Valley (2002-2003 breeding season, i.e. before rabies), Sanetti Plateau (2003-2004 breeding season), and Morebawa (2003-2004 breeding season) were well known as monitoring effort was high in these areas. Territory boundaries in other areas were less well known as they were based on fewer data collected between late 2003 and early 2005. Territories in white are only estimates of territory boundaries as no spatial data were available for these packs. Numbers refer to the ID for each pack in Table 1. Objectives of the EWCP Monitoring Programme Based on consultations between field staff in the EWCP and other organisations working in the Bale Mountains at this time, the objectives of the wolf monitoring programme for Bale were laid out as follows: To obtain baseline data on population size, density, abundance, and genetic diversity To estimate population size annually and monitor trends over time To monitor pack size, composition, territory configurations, and breeding success for a number of focal packs To detect disease epidemics To assess long-term changes in genetic diversity Monitoring Changes in Population Size The monitoring programme s primary aim is to quickly and reliably detect changes in population size. Pack enumeration has proven useful for monitoring demographic changes in focal packs and Walia-Special Edition on the Bale Mountains 34
long-term study areas. However, total counts of focal packs are only useful for calculating absolute population size if all packs in the Bale massif are monitored and pack demographics are reliably determined for each pack, both of which require a substantial investment of resources and are difficult (if not impossible) to achieve. The tremendous quantity and quality of monitoring data collected by the EWCP on focal packs over many years has made it possible to follow meaningful trends in group size, pack territories and reproductive success. While variation in monitoring effort across packs, study sites, and years makes estimating total population size a challenge, extrapolation of these data have provided a means of assessing population trends up to present. As a complementary approach, an index of abundance from the Web Valley and Sanetti Plateau transects has been applied successfully to estimate wolf trends in high density wolf areas (Marino et al. 2006). However, the index was deemed less accurate at estimating wolf abundance in low-density areas (Marino et al. 2006) Monitoring Long-term Genetic Diversity Genetic diversity is deemed necessary for population persistence because it allows the evolutionary adaptability of populations to natural or human-induced environmental changes (Allendorf and Leary 1986; Gilpin and Soulé 1986; Lande and Barrowclough 1987) and counters the negative effects of inbreeding on fitness (Lande 1988; Falconer 1989; Frankham 1995; Amos and Balmford 2001). Thus, one of the EWCP s conservation goals is to maintain 90% of the species genetic variation over 200 years - the recommended target for the genetic minimum viable population (MVP) (Ralls and Ballou 1986; Soulé et al. 1986). From 2002 to 2005, a study was undertaken to examine the current level and distribution of genetic variation in the Bale wolf population (Randall et al. 2010). A total of 156 Ethiopian wolves present in the population during this period were sampled and genotyped at 17 polymorphic microsatellite markers. Within subpopulations, allelic richness ranged from 4.2 to 4.3 (with 4 to 12 alleles per locus) and expected heterozygosity (H e ) ranged from 0.584 to 0.607. A similar analysis of genetic variation is currently being completed for other populations across the species range (Gottelli et al., unpublished data). These data provide a baseline from which changes in genetic diversity can be monitored. Genetic methods can also be used for monitoring population size and demography; and noninvasive genetic sampling is a particularly useful tool that can be applied to species that are either too rare or elusive to observe, or where the threatened status of a population precludes or deters capture and handling of animals (Kohn and Wayne 1997). Indeed, individual identification of wolves using genetic methods has been possible in both the Bale population (Randall et al. 2007; Randall et al. 2010) and smaller populations in North Ethiopia (Asmyhr et al. unpublished data, Gottelli et al. unpublished data). However, low quality or quantity DNA obtained from faecal or hair samples are more prone to erroneous genotyping which have undesirable consequences for analyses using genetic data (for example, genotyping errors Walia-Special Edition on the Bale Mountains 35
lead to greatly inflated population estimates, Waits and Leberg 2000; Creel et al. 2003). Rigorous laboratory protocols can reduce the number of genotyping errors, such that their consequences for demographic and genetic monitoring are sufficiently minimised. Randall (2006), determined that (i) faecal samples provide a useful source of DNA for noninvasive genetic studies in Ethiopian wolves, and (ii) three PCR replications were sufficient to obtain reliable multilocus genotypes in this study if the DNA concentrations in faecal extracts was sufficiently high. Thus a system of extract sorting (Morin et al. 2001) is recommended to substantially increase the reliability of the genotyping results while alleviating the need for excessive and costly PCR replications. This means selecting a priori those samples with sufficient DNA to give reliable genotyping results with minimal replications. One drawback of monitoring population size and demography using genetic methods is the longer time required to process samples in the lab (particularly non-invasive faecal samples) and, thus, obtain results. Conclusions From a conservation management perspective, the EWCP s monitoring programme for Bale has three main aims: (1) to obtain reliable, annual population estimates for the wolf population that includes all available wolf habitat in the Bale massif (including both low and high density areas), (2) to detect rapid, short-term declines caused by outbreaks of disease that might necessitate immediate intervention or other management action, and (3) to detect slow declines (or increases) over the longterm, resulting from habitat modification/loss or other environmental and demographic factors. A fourth aim is to monitor genetic diversity over time. Importantly, the future monitoring programme should ensure comparability of population estimates with the existing long-term dataset. Given these aims, EWCP has designed a monitoring protocol for Bale that targets six focal packs in each of three core wolf areas (i.e. Web, Sanetti and Morebawa) to ensure early detection of drastic declines and clinical signs of disease. Data collected includes detailed information on pack size, structure, territorial boundaries, and breeding success for all focal packs. In addition, the monitors collect data on a similar number of peripheral packs for each core study area. Elsewhere in the Bale massif, demographic and reproduction data are collected opportunistically. Non-invasive genetic sampling could also provide a tool for monitoring changes in wolf demography and genetic diversity throughout the species range, particularly where other census methods are not feasible. References Allendorf, F.W. and Leary, R.F. 1986. Heterozygosity and fitness in natural populations of animals. In Conservation Biology: The Science of Scarcity and Diversity. (Soulé, M.E. (ed)) pp. 57-76. Sunderland, Massachusetts, Sinauer Associates. Amos, W. and Balmford, A. 2001. When does conservation genetics matter? Heredity, 87: 257-265. Ash, N.J. 2001. Expansion of Ethiopian wolf conservation to northern Ethiopia. Canid News 4 (2): Online Walia-Special Edition on the Bale Mountains 36
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