Appendix
Methods: Reasons why high-resolution GE imagery should not be the primary basis for encroachment
mapping
Our methods were primarily based on manual interpretation of Landsat imagery, and only used higher
resolution imagery in a supplemental capacity for training and verification. While there are obvious
advantages to basing savanna land cover mapping on high-resolution imagery available through GE
(including IKONOS, QuickBird, WorldView, and/or Geoeye imagery provided by Digital Globe), several
disadvantages preclude its use as the primary basis of the mapping. Firstly, the availability of high
resolution imagery is relatively recent, so it cannot be used for the historical component of land cover
change mapping; and in order to minimize between-sensor methodological variation, is arguably not
recommended as the primary basis of the contemporary component of land cover change mapping either.
Secondly, when served through Google Earth, high-resolution imagery is free, but not in a stable, reliable,
downloadable format ready for analysis within Geographic Information Systems (GIS) software such as
ArcMap. When obtained in its native format from the original license holders, it is extraordinarily
expensive; raw SPOTMaps imagery for our study area would have been priced well in excess of one
million dollars. Thirdly, high-resolution imagery over savanna regions is usually obtained at times of year
when large-area patterns of cultivation are actually harder to recognize than with coarse-resolution
imagery acquired during the optimal wet/dry transition window. We frequently detected remote cultivated
areas first using coarse-resolution imagery from the wet/dry transition, and then confirmed their existence
only when zooming in very close to the area in Google Earth. Fourth, in the case of SPOTMaps
distribution through Google Earth, the georeferencing was inaccurate throughout most of our study area
by over 100 m. Finally, and especially when considering expansion to the mapping of Zambia as a whole
(752,618 km2), manual interpretation of high-resolution imagery versus Landsat-scale imagery would
potentially be prohibitively time-consuming and difficult to standardize across different types of
landscape.
Results: Potential drivers of encroachment radiating out from major national roads
The expanding national cotton industry may account for much of the expansion of cultivated area, as the
total national cotton crop area grew 68 km2 per year between 1993 and 2001. Much of the cotton farming
area falls within our study area east of the Luangwa River, and is largely produced by small-scale farms
of the type illustrated in Figure 4d (Tschirley & Kabwe 2009). Charcoal production also likely accounts
for a substantial proportion of the increased human footprint; estimated nation-wide rates of charcoaldriven forest degradation have accelerated from 170 km2 per year in 1969 to 730 km2 per year in 2008
(Kalinda et al. 2008). Assuming the LV is representative of the nation, this translates into approximately
78 km2 per year within the LV study area, much of it contributing to net long-term deforestation
(Chidumayo et al. 2001, 2012). International migration has also played a role; Eastern Province has a long
history of accepting refugees from what is now Mozambique. In 1987, over 23,000 refugees were
emplaced on 150 km2 of hitherto sparsely populated land at the Ukwimi Refugee Settlement in Petauke
District (Fig. 5) (Gray 2009), increasing the district population substantially from its 1980 total of
157,065. After having provided the impetus for government-facilitated land clearing and infrastructure
development in the area, most of the refugees returned to Mozambique a decade later. Ukwimi was then
used for internal resettlement of Zambians, as well as for Angolan refugees in 2001.
Results: Potential explanations for contraction of the human footprint in remote areas
In West Petauke GMA, four areas of 1960s settlement mapped by Schultz (1976) were apparently
abandoned by 1985 and have never re-appeared (Figure 5a). They existed in the still very isolated
territory of the Ambo tribe along the lower reaches of the Lukusashi River but well upstream of its
confluence with the Luangwa near the Great East Road (Brelsford 1965). At least as recently as the
1950s, the Ambo frequently shifted villages when soil fertility became depleted and huts decayed, and
they occasionally abandoned areas altogether after a spate of deaths or a ‘vision’ of being happier
elsewhere (Stefaniszyn 1964). Much of the Ambo territory is beyond the boundary of our study area, so
village shifting and abandonment for areas to the west could lead to reduction in the total mapped human
footprint without implying a reduction in human population. The area is only accessible only by two
rough roads descending the Muchinga Escarpment from the west and northwest, suggesting its continued
isolation from the expansive forces of the developing world. However, formerly isolated cultivated areas
upstream along the Lukusashi have merged into a continuously inhabited strip since 1985, suggesting that
any long-abandoned floodplains in the area may yet be re-incorporated into the actively worked Ambo
territory.
A similar history of contraction and expansion in cultivated area is apparent in the Munyamadzi GMA,
where we estimated the human-impacted area to have shrunk by 12 km2 (0.46%) per year before 1985,
and then increased by 5 km2 (0.17%) per year after 1985. As with the Ambo in lower LV (i.e. the
Lukusashi tributary), the Valley Bisa in the Munyamadzi GMA of the central LV were known to
frequently shift villages for reasons including flooding and alleged sorcery (Marks 2005); but this does
not necessary explain a reduction in total mapped cultivated area. Drought occurred in the area between
1983 and 1988 (Marks 2005), possibly explaining apparent reductions in human impact as simply
temporary reductions in cultivated area without any fundamental change in employment, population size,
or population distribution. But employment and population changes probably also played a role. In the
1970s, the national economy worsened, poaching dramatically increased, and the area became a source of
bushmeat to the Great North Road region (Gibson 1995, Marks 2005). The bushmeat industry is an
attractive alternative to farming (Brown & Marks 2007), and one that could lead to local reduction in
cultivated area. Larger-scale population changes probably also played a role. Substantial migration from
rural to urban areas took place after independence in 1964, particularly as far as the nearest railway line
(Mwanza 1979; Hedlund and Lundahl 1983). The Tanzania-Zambia Railway was completed in 1974,
parallel to the Great North Road and passing within about 40 km of the settlements in Munyamadzi
GMA, so out-migration from Munyamadzi to the Great North Road probably occurred around this time,
driven by expectation of higher income and better living conditions. Urbanization rates stabilized and
even reversed in the 1980s (Ogura 1991; Simatele 2007; Potts 2009), which may partly explain the
reversal in the decline in cultivated area in Munyamadzi GMA after 1985.
GKE and KAZA TFCA
As with LV, encroachment in the GKE has been rapid and extensive in some areas, and stable in others. A
broad accelerating swath of encroachment has extended toward KNP from a major national road (the
Lusaka-Livingstone Road) and railway since the 1960s. The only barriers to this encroachment have been
the national park boundary, and the non-cultivatable wetlands of Kafue Flats between Bilili and Namwala
GMAs. GMA boundaries have apparently had no effect on encroachment, to the extent that Bilili GMA is
now 99% impacted, Namwala GMA is 84% impacted, and Mumbwa GMA is 54% impacted (Table 1).
The originally intended ability of Bilili and Namwala GMAs to function as buffer zones to the national
park has been essentially eliminated, and Mumbwa GMA is on a similar trajectory. The corridor between
KNP and the rest of KAZA TFCA (in Namibia, Botswana, and Zimbabwe) has experienced substantial
encroachment, but also positive steps toward wildlife protection. The corridor includes Sichifulo GMA,
parts of Mulobezi GMA, some forest reserves, and the newly declared Simalaha Conservancy (Fig 5c.). A
GMP for Sichifulo was approved in 2011, designating much of the GMA as a conservation zone. Parts of
this conservation zone have been encroached, but this was offset to some extent by government-led
removal of illegal settlers and a ministerial warning of the potential for being eliminated as a functioning
GMA (Namugala 2009, Republic of Zambia 2011).
To the west of KNP in Western Province, some settlements have disappeared since the 1960s, others have
a relatively stable human footprint, and others have merged at a relatively manageable rate along
watercourses (Fig 5c). The pattern is exemplified by the Nyambi area within Mufunta GMA, immediately
west of the national park. Here, there is a stable or reducing human footprint, and a documented
circumstance of human migration away from remote, poorly served areas toward a major road (the M9) to
the north of the study area (Scott 2002). The Mulobezi GMA spans the interface of the two patterns, with
remote and stable communities just to its north, but rapid encroachment from the south, near the terminus
of the Mulobezi Railway line that extends northwest from Livingstone.
Results: Buffer zones without a GMA designation
Areas currently acting as buffer zones around national parks but without a GMA designation could
experience a wide range of fates. They are exemplified by the Mupamadzi River headwaters, and the
Kafue-KAZA corridor. The Mupamadzi River headwaters lie northwest of SLNP in a region that for
many years was largely free of human impact (save for an isolated settlement at Kamwendo) but that is
now subject to a substantial wave of encroachment emanating from the Great North Road (Fig. 5a). The
portions immediately on the SLNP boundary are on the steep Muchinga Escarpment, while the portions
between the escarpment and the Great North Road have been designated as the Mupamadzi Farm Block
and subdivided for large-scale private farming (Department of Agriculture and TAZCORR Services
2010). In the absence of guidelines on the type of land use for the farms, there is a risk of destruction of
rare large undisturbed tracts of miombo woodland. These wood lands are an important source of annual
recharge to the Luangwa river system and an important ecological corridor spanning the Great North
Road between SLNP and the Lavushi Manda National Park (not shown in Fig 5). The privately managed
Mutinondo Wilderness lies in the center of this area, anchoring what is now a relatively undeveloped
landscape
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