Masai (Giraffa camelopardalis ssp. tippelskirchi)

Appendix 1. Masai Giraffe Range and Population Estimates (Historic through Current) For Kenya there are data from the counties that encompass the majority of the range of the Masai Giraffe: County which includes Amboseli, Chyulu Hills, and National Parks and adjoining pastoral lands, County including the Masai Mara National Reserve and surrounding pastoral lands, Taita Taveta including Tsavo National Park, , , , Tana River, /Makeuni Counties, and the Wildlife Conservancy (NWC) - a collection of 33 wildlife holdings including three national parks (Hell’s Gate, Mt. Longonot and Lake Nakuru) and private reserves (Ogutu et al. 2017). Most data are from aerial sample counts from the Directorateof Resource Surveys and Remote Sensing of Kenya (DRSRS). Time periods covered were 1977 to 2015 (2014 for Taita Taveta, Tana River,Kajiado and Narok, 2015 for Kitui and Machakos/Makueni, and 2013 for Kilifi and Kwale). Data from NWC are bi-annual ground counts, conducted in all units of the conservancy by Kenya Wildlife Service (KWS) and the conservancy members from 1996 to 2015.Data were compiled, analysed and provided to us by Joseph O. Ogutu, University of Hohenheim, Germany.

Masai Giraffe declines have been dramatic in most regions of Kenya in recent decades (Table 1). Giraffes in Narok, Kilifi, Kitui, Tana River and Machakos/Makeuni County declined by 76-88% (Figures 3, 6, 7, 9, 10), Kajiado and Kwale Counties experienced roughly 50% declines (Figures 1, 8), and Giraffe numbers in Taita Taveta County declined by 5.2% (Fig. 4). Only in the NWC were Giraffe numbers stable or increasing, in total increasing by 190% from approximately 280 to 811 in the period 1996 to 2015 (Table 1, Fig. 5). All told Masai Giraffe numbers in these regions of Kenya declined from approximately 32,000 to 12,000, a 63% reduction, in approximately 38 years, a reduction of nearly two-thirds of its Masai Giraffes since 1977 (Table 1).

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Table 1. Masai Giraffe numbers in areas of southern Kenya

mean mean

County 1977-80 2011-2014 Change % change Taita Taveta 2,407 2,282 -125 -5.2 Narok 7,982 1,925 -6,057 -75.9 Kajiado 9,613 4,678 -4,935 -51.3 Kilifi 1,163 136 -1,027 -88.3 Kitui 3,387 393 -2,994 -88.4 Kwale 517 261 -256 -49.5 Tana River 5,751 1,155 -4,596 -79.9 Machados/Makeuni 511 114 -397 -77.7

1996-98 2013-15

Nakuru Wildlife 280 811 531 189.9 Conservancy Kenya Totals 31,611 11,755 -19,856 -62.8 Data source: Jospeh O. Ogutu

For several of these regions there are recent published analyses describing substantial land-use change and human population growth in recent decades.

Kajiado County. Wildlife in Kajiado reside in the protected areas and the much larger area of Maasai group ranches. Ogutu et al. (2014 and references therein) describe broad changes in land use and population within the group ranches. Human population has increased from 85,903 in 1969 to 406,054 in 1999 and to 687,312 in 2009; an annual rate of increase of ~4% (Ogutu et al. 2014). These include increases in cultivation, particularly in wetlands, fencing, sedenterization and individual land tenure among pastoralist Maasai. These changes have led to a more uniform human presence across the landscape as bomas disaggregate. The result is that livestock numbers have generally declined, but their spatial distribution has increased. This corresponds with the decreasing population size (Fig. 1) and spatial distribution of Masai Giraffes and most other wild ungulates in the county (Ogutu et al. 2014).

The trends within specific areas of the county have been even more dramatic. Ogutu et al. (2013) analysed data for the Athi-Kaputiei ecosystem that includes Nairobi National Park and the plains to the south. There Giraffe numbers have declined by 84% from 1977 to 2011 (602 to 94 estimated individuals; Fig. 2). Interestingly, Giraffe numbers within the national park have remained reasonably stable at approximately 100 individuals. A photographic mark-recapture survey in March 2014 estimated the park population at 119 +/- 48 (Wildlife Direct 2014).Reid et al. (2008) and Said et al. (2016) have described in detail the habitat loss and fragmentation in this system.

Narok County. This includes the Kenyan portion of the -Mara Ecosystem and includes the Masai Mara National Reserve and the Maasai group ranches to the north on the Mara, Siana and Loita Plains. In the northern Loita Plains, the high end of the regional rainfall gradient, extensive areas have been leased for large-scale mechanized wheat farming. In the remaining group ranch areas similar changes are occurring as in other areas of Kenya. Lamprey and Reid (2004) estimate human populations on Koyiaki group ranch, one of the larger and more important wildlife ranches, increased at an annual rate of 4.4%. Related, livestock per capita has declined and the number of households has increased, as has the spatial distribution of permanent settlements. Individual land tenure has increased as has subsistence agriculture among the Maasai. Estimates of Masai Giraffe population size have declined from 7,982 to 1,925 during the period 1977 to 2014 (Fig. 3 and Ogutu et al. 2011 and Ogutu et al. 2016).

Taita Taveta County. All of Tsavo West and much of Tsavo East National Parks are within this county. This region has received much less attention from researchers than has Narok and Kajiado counties, however, Mbau (2013) recently analysed land use change in the wildlife dispersal area to the west of Tsavo West NP over the period 1987- 2011. She found an approximate tripling of agricultural land during this period and a reduction of forest by 11%, woodland by 55% and shrublands by 17%. Human population growth was 3% annually to a density of 105 individuals/km2. However, Giraffe decline has been less severe in this region declining 5%, from 2407 to 2282 over the period 1977-2014 (Fig. 4).

Nakuru Wildlife Conservancy.NWC is a collection of 33 wildlife holdings including three national parks (Hell’s Gate, Mt. Longonot and Lake Nakuru) and private reserves totaling 1,417 km2. Wildlife management in the conservancy occurs under the umbrella of the Nakuru Wildlife Forum. The region has experienced rapid population growth, urbanization and expansion of commercial flower farms, the latter kicking off in the early 1980’s. The human population of increased more than three times in the period 1969-1999 and a further 74% from 1999 to 2009 (Ogutu et al. 2017). Human population density was 41/km2 in 1969, 158/km2 in 1999, and 214/km2 in 2009.

Despite similar changes in land use and human population growth this was the only region that showed an increase in Masai Giraffe numbers in recent decades, from 280 to 811 individuals over the period 1996 to 2015 (Fig. 5).It is important to note that the time series from NWC begins much later than for the other areas (1996 versus 1977) and is likely that much of the wildlife of this region had been lost prior to the period of data collection due to expanding agriculture and urbanization. Reports from the first half of the 20th century (summarized in Ogutu et al. 2017) describe “one of the richest wildlife assemblages in .” The increases in Masai Giraffes and a number of other ungulate species (Ogutu et al. 2017) probably represents a degree of population recovery from lower levels that were reached in the late 1980’s early 90’s due to land use change and human population increase. Ogutu et al. (2017) conclude the recovery “has largely been due to the coordination and support provided to the landholders and land users by governmental, international and local non-governmental organizations operating under the umbrella of the Nakuru Wildlife Forum.”

[note: Three of the NWC members Lake Nakuru National Park, Kigio and Soysambu Conservancy support the Rothschild’s Giraffe rather than the Masai Giraffe. Counts for these three areas are not included in the NWC totals presented in Table 1. However, the numbers presented in Fig. 5 from Ogutu et al. 2017, do include the Kigio and Soysambu Conservancy counts but not those from Lake Nakuru National Park.]

Figure 1. Estimated Masai Giraffe numbers in , Kenya. Figure from Ogutu et al. 2014. In this figure and figures 3, 4, 6-10 the trend line and point-wise 95% CI (shaded band) are derived from an analysis of the time series of individual population estimates from aerial counts (see text for details of aerial counts).The points represent the individual population estimate for that survey. The trend was estimated with a multivariate semiparametric generalized linear mixed model with a negative binomial error distribution, a log link function and penalized cubic B-spline smoothing with a third order difference penalty. The modeled trend is based on the Giraffe counts but also reflects the covariance with the counts of other non-migratory, wild ungulates in the surveys. This multivariate trend estimation produces more precise estimates of the focal species trend because it allows for a trend component common to all species, which may be due to all species responding in a similar way to environmental trends such as land-use change or climatic variability (Ruppert et al. 2003), and a trend component specific to each species. The model is very flexible and allows for potentially curvilinear trends, irregularly spaced surveys, non-normality of the counts and variation in the variance of the counts with their mean. The population size estimates given for the beginning of the time series (1977-80) and the end (2011-14) are the averages over those three-year periods of the population size predicted by the trend line. For further details see Ogutu et al. 2011.

Figure 2. Estimated Masai Giraffe numbers in Athi-Kaputiei ecosystem, Kenya. Figure from Ogutu et al. 2013.

Figure 3. Estimated Masai Giraffe numbers in , Kenya.Figure from Joseph O. Ogutu, unpublished.

Figure 4.Estimated Masai Giraffe numbers in the Taita Taveta County, Kenya. Figure from Joseph O. Ogutu, unpublished.

Figure 5.Estimated Masai Giraffe population density in the Nakuru Wildlife Conservancy, Kenya. Figure from Ogutu et al. (2017)

Figure 6.Estimated Masai Giraffe numbers in , Kenya. Figure from Ogutu et al. (2016).

Figure 7.Estimated Masai Giraffe numbers in , Kenya. Figure from Ogutu et al. (2016).

Figure 8.Estimated Masai Giraffe numbers in , Kenya. Figure from Ogutu et al. (2016).

Figure 9.Estimated Masai Giraffe numbers in , Kenya. Figure from Ogutu et al. (2016).

Figure 10.Estimated Masai Giraffe numbers in Machakos/Makueni Counties, Kenya. Figure from Ogutu et al. (2016).

Other recent surveys. Recently KWS and TAWIRI conducted a series of Systematic Reconnaissance Flight (SRF) surveys in the Kenya- border areas (KWS- TAWIRI, undated, Okello et al. 2015).Counts were conducted in the wet and dry seasons of 2010 and 2013 counted Masai Giraffes in the Amboseli and Magadi/ regions in southern Kenya. They estimated 2,063 Masai Giraffes in Amboseli and surrounding group ranches and 670 in Magadi/Namanga (estimates averaged across seasons and years). Estimates increased between 2010 and 2013 and this was interpreted as population recovery following the severe drought of 2007-2009 (Okello et al. 2015).

The Great Elephant Census conducted SRF surveys in the Amboseli and Tsavo ecosystems in 2015. Their estimates were 2,350 individuals for Amboseli, similar to the KWS-TAWIRI estimates, and 7,970 for Tsavo (GEC 2015). There is no comparison for Tsavo as the Kenya DRSRS surveys are organized by county not by protected areas.

TANZANIA

The Masai Giraffe is widely distributed in central and northern Tanzania. Figure 11 shows the recent distribution of Giraffe sightings from the Tanzania Atlas Project. Data were acquired from TAWIRI’s systematic reconnaissance flights (1986- 2016) in nine regions of Tanzania that encompass large protected areas – including national parks and game reserves (see map of areas in Fig. 12). Data were accessed through the TAWIRI SISTA database or in recent TAWIRI reports. These same data, through 2000, were analyzed in Stoner et al. 2006 and 2007. Our analyses of the 1986- 2016 data suggest that over this period of time Masai Giraffe populations have experienced statistically significant declines in the Katavi and Ruaha-Rungwa regions (Fig. 13, see notes on analysis below). The decline in Katavi was already apparent in the data up to 2000 that were analyzed by Stoner et al. (2006) using different statistical methods. But the Ruaha trend has only become apparent later, Stoner et al. (2006) classified it as stable based on the data up to 2000.

Figure 11. Giraffe sighting locations in the Tanzania Mammal Atlas Project. Downloaded from http://www.tanzaniamammals.org/uploads/maps/l079_Giraffe.jpg on 6-24-2015.

Figure 12.Location of the ecosystems covered by TAWIRI’s systematic reconnaissance flights.(Figure from Stoner et al. 2006)

The regression analyses for the remaining seven regions did not indicate statistically significant trends. The slope of population estimate versus time was negative for Selous- Mikumi, Tarangire-Manyara, Mkomasi and Ugalla regions and positive for Serengeti, Burigi-Biharamulo, and Saadani.

Population estimates from the SRF counts are highly variable and in some cases have large confidence intervals complicating interpretation of trends. Counts were not done in every year of this 30-year period and sites differ in how frequently surveys were completed (range: 4 for Burigi-Biharamulo, to 13 for Ruaha-Rukwa).Also, some counts were done in the dry season and others in the wet season. Given this methodological variation we attempted two methods to smooth this variation to derive an estimate of the change in population sizes across this 30 year period.

First, we chose a set of population estimates from early and late in the time series for each ecosystem. We then averaged those estimates to provide an early and late estimate of population size, and estimated change in population size, for that ecosystem (Table 2). The estimates averaged are enclosed by boxes on Figure 13. Generally, the early estimates were for years before 1995 and late estimates came from years after 2005, but since the time period covered for each time series differed, there are some exceptions to this. These time ranges encompassed different numbers of estimates in each ecosystem because of unequal numbers of surveys(Fig. 13). Comparing population estimates from early in the time series to more recent years suggest substantial declines have occurred in several regions (Table 2). Overall, across this 30-year period population estimates for these areas indicate the Masai Giraffe has declined by 37% from approximately 37,000 to 23,500.

Averaging over a number of years can obscure any underlying trend (positive or negative) in the estimates. To circumvent this we generated alternative estimates of population change by using the regression equations from the regression of ln (population size) on year to generate point estimates of population size for the beginning and end of each time series. These estimates appear in Table 3 and suggest slightly larger declines than do the averaged estimates in Table 2. They suggest the Masai giraffe in Tanzania has declined from roughly 39,500 to 23,000, or a 43% decline. These include large declines in some regions, including 69% in Ruaha-Rungwaand 87% in Katavi-Rungwa.

Both sets of estimates suggest that a large majority of the country-wide estimated decline in Masai giraffe numbers occurred in the Ruaha-Rungwa and Katavi-Rukwa ecosystems.

Recent, but not longitudinal, abundance estimates were available for several other regions. Surveys conducted in 2013 estimated 813 giraffes in the West Kilimanjaro region and 1767 giraffes in the Lake Natron region. Surveys in 2014 in the Malagarasi- Muyovosi Ecosystem produced estimates of 706 giraffes (exclusive of the Ugalla Game Reserve). Mahenya (2016) cite a population size of <100 for Arusha National Park. Since these are not longitudinal data, they cannot be incorporated in our estimate of population change, but this additional 3386 giraffes brings the estimate of the present total number of Masai giraffes in Tanzania to a total of 26,372-26,887.

Table 2. Masai Giraffe numbers in areas of Tanzania. (TAWIRI SRF data). Early and late estimates are the mean of the estimates identified in Figure 13.

Early Recent Ecosystem estimate estimate change %change Selous-Mikumi 3077 2963 -114 -3.7 Ruaha-Rungwa 11724 5110 -6614 -56.4 Tarangire- Manyara 4191 2751 -1440 -34.4 Serengeti 9882 10167 285 2.9 Katavi-Rukwa 6418 1279 -5139 -80.1 Burigi- Biharamulo 148 77 -71 -48.2 Sadaani 392 460 69 17.5 Mkomazi 1080 419 -661 -61.2 Ugalla 364 276 -88 -24.2

TOTAL 37275 23501 -13773 -37.0

Table 3. Masai Giraffe numbers in areas of Tanzania predicted from regression equations for the starting and ending years of the data sequence. (TAWIRI SRF data)

Start End Ecosystem date Estimate date Estimate Change %change Selous-Mikumi 1986 3728 2014 3047 -682 -18.3 Ruaha-Rungwa 1988 13552 2015 4195 -9356 -69.0 Tarangire- Manyara 1990 3863 2016 2777 -1085 -28.1 Serengeti 1988 9685 2010 10696 1011 10.4 Katavi-Rukwa 1988 7299 2014 951 -6347 -87.0 Burigi- Biharamulo 1990 136 2014 236 100 73.3 Sadaani 1998 307 2010 471 164 53.4 Mkomazi 1991 890 2014 405 -485 -54.5 Ugalla 1990 449 2014 207 -242 -53.9

TOTAL 39459 22986 -16923 -42.9

Figure 13. Tanzanian Masai Giraffe population estimates, and 95% confidence intervals, derived from SRFs in nine large ecosystems 1986–2016 (TAWIRI, unpublished data). Boxes enclose the sets of population estimates that were averaged to produce the numbers summarized in Table 2.Open squares and closed triangles represent wet and dry season estimates respectively. Regressions lines on untransformed data provided for illustrative purposes.

For several of these regions, recent published studies provide additional insight into the status of these populations:

Serengeti. The TAWIRI SRF data suggest a slight increase in the Serengeti ecosystem over the past 30 years (Tables 2 and 3, Fig. 13) .However, a recent study by Strauss et al. (2015) calls that into question, at the least for the portion of the ecosystem contained within . Using photographic mark-recapture methods they estimated the local population density in three areas of Serengeti National Park: Seronera, Kirawira and Bologonja. They extrapolated from densities in those areas to areas of similar habitat elsewhere in the Park. Based on this extrapolation they suggest the total Serengeti NP population is approximately 3,500, considerably lower than the estimate of 5886 from the 2010 TAWIRI SRF data for the park. Furthermore, they compared their population estimates for those three areas in 2008-2010 to those from Pellew (1983) in 1975-76 and noted declines of 67-86%. They attributed the declines to illegal hunting and food limitation due to the increasing relative abundance of unpalatable tree species, especially Acacia robusta

Tarangire-Manyara. A study by Lee (2015) using photographic mark-recapture methods estimated metapopulation growth rate for the Tarangire-Manyara ecosystem in 2012- 2014 and found a slightly declining trend (λM = 0.99). Demographic analyses of sub- populations at five sites in the core of the ecosystem revealed spatial variation in adult female survival that was positively correlated with the intensity of anti-poaching patrols. Total population size of adults within the sampled area was 1,225 individuals (1.07 adult Giraffes / km2) comprised of 790 adult females and 435 adult males.

Katavi-Rukwa. Caro (2008) evaluated several possible causes for the declines in a number of ungulate species, including Giraffe, in the Katavi-Rukwa system. Potential causes assessed included disease, rainfall (food limitation) and illegal hunting. He concluded that there was only support for illegal hunting as the cause of declines. Based on interviews with 82 hunters in villages along the southwest boundaries of the park and game reserve, Caro and Martin (2013) estimated that 98 Masai Giraffes are illegally hunted annually.

[Notes on analysis.The area encompassed by the aerial surveys varied among years.For each site we corrected the population estimates to an equal area, the largest area surveyed in any survey done at that site. Surveys that covered less than 50% of the largest survey area for that site were eliminated due to likelihood of the data being unrepresentative because of sampling issues. Similarly, if one survey area was twice the size of the next largest survey area for the ecosystem, that data point was also discarded. The statistical significance of trends were assessed by regressing natural log transformed population estimates against time. The statistical significance of linear regression on time needs to be interpreted with caution. Temporal autocorrelation is possible in counts across time which biases p-values downward. However, this effect is generally small (Wilson et al. 2011). The use of state-space population models eliminates this problem, however, these generally require longer time series and are much less powerful than log regressions (Wilson et al. 2011).]

In Table 4 we combined the estimates for Kenya and Tanzania (Tables 1, 2 and 3) to produce a range-wide estimate of Masai Giraffe population decline. Because we have estimated the decline in Tanzania using two methods, we have two range-wide decline estimates.

Table 4.Estimates of total Masai Giraffe population size reduction (Kenya and Tanzania combined)

Using the multi-year means for Tanzania (Table 2) Initial Change %change 68886 -33629 -48.8 Using the regression point estimates for Tanzania (Table 3) Initial Change %change 71070 -36329 -51.1

The estimated percent decline for Tanzania and Kenya combined is 49% to 51%. Probable causes are habitat loss and illegal hunting. Criteria A2 applies: “…causes of reduction may not have ceased OR may not be understood OR may not be reversible.” as these causes have not been fully documented, are likely still occurring, and habitat loss is generally not easily reversible.

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