4.1. Spatiotemporal Distribution of Drought
The empirical evidence from the current study shows that, during the period of 1983–2006, as well as pre-1983 and post-2006, occurrences of drought in Kajiado were frequent and had indistinct spatiotemporal annual trends (
Figure 2a,b). The significant temporal and spatial contrast (
p < 0.05) for drought further attests to this variation among the drought years. They were also widespread, variously cyclic, and sometimes temporally clustered (
Figure 2a and
Figure 4). The current empirical evidence also reveals that an estimated 86% of drought occurrences in this rangeland, from 1983 to 2006, were in the
major drought category (
Figure 2a). Major droughts have occurred in this rangeland pre-1983 and post-2006 (see
Figure 2b). In fact, each decade in the 1940s, 1950s, and 1970s recorded over 50% of the events, which translates to a minimum of five drought events in 10 years. It must be noted that this frequency of and spatial vastness of drought corroborates well with the recorded drought events, mainly major and extreme drought, that have plagued Kenya and the greater horn of Africa [
3,
4,
7]. This finding indicates that this climatic hazard is a common occurrence in this region. This interpretation accords well with the conclusion that drought is a normal climatic occurrence across the rangelands of East Africa [
43,
44]. The indistinct spatiotemporal annual trend of drought events does not only indicate that droughts manifested with differential intensity across the district annually, but also that they were temporally unpredictable. This finding, in concert with the region’s characteristic high rainfall variability [
6,
44,
45], indicates that this rangeland harbors climatically diverse micro-regions. It is instructive to explore how the frequent occurrences of
major drought events manifest within these micro-regions: this is discussed later in this paper.
The evident manifestation of biennial and decadal cyclic drought events (from
Section 3.1, such manifestations are also evident for the period pre-1983 (biennial, e.g., 1972/74/76, consecutive and decadal, e.g. 1960–1961/1971–1972/1980–1981) and post-2006 (consecutive and biennial, e.g., 2010–2011, 2011–2012, and 2014; and decadal, e.g., 2009)) indicates a potential presence of a recurring drought-forcing, and, by extension, it suggest predictability of occurrences of this climatic hazard in the region, if such forcing is deciphered. It must be pointed out that, with regard to climatic forcings across East Africa, extreme climatic events are triggered by specific teleconnections with El Niño-Southern Oscillation (ENSO) [
46,
47], mainly El Niño for extreme rainfall, and La Niña for extreme droughts. This means that, by monitoring the behavior of ENSO and other forcings and/or variables, the predictability of meteorological droughts for the region can be improved. Moreover, it is highlighted that, since the established period for discerning change in climate is 30 years on average of weather [
48], the current study, having documented events spanning over 10 decades, provides sufficient initial data to contribute, in part, to such efforts. Beside their cyclic manifestation, droughts were sometimes temporally clustered, with, occasionally, the cluster containing an episode of extreme drought and often being preceded by below-average rainfall (poor rains) conditions (
Figure 2a,b). Apropos this last decade, the current empirical evidence reveals that the two extreme drought events (2005 and 2009) were clustered around four events of droughts or poor rains (
Figure 2a,b and
Figure 4), [
3,
4,
6]. The temporal clustering indicates that drought occurrences have been consecutive, and that their return period has shortened. This consecutiveness is attested in survey data (
Figure 4) where drought years were continuous.
It is pointed out that the occurrence of some of consecutive drought years contains a paradoxical interpretation: it could signify one major event that spanned the chronological scale, for example 2000 and 2001, 1983 and 1984 (
Figure 2 and
Figure 4); it could also signify that there were actually separate events that presented with varying intensities in different places, and therefore, the reporting of drought should account for this connectivity and disconnectivity. This finding reveals the necessity for attaching a shorter timescale, for example a season or number of drought days. Apropos this finding, the strength of the pastoralist drought (see
Section 4.2 for definition) is clear: the usage of the variable “
delay/early termination of seasonal rains (
Table 1)” implicitly indicates drought days, and “failure of long-rains (
Table 1)” explicitly indicates a specific season. Similarly, this finding reveals the inherent complexity in the precise determination of the actual time of termination of a given drought.
The evident spatiotemporal pattern of drought at finer-resolution scales and shorter timescales, particularly the shifted mosaics of drought spaces and the manifestation of cyclic events and clustering (
Figure 2 and
Figure 3), is rarely documented for this rangeland. The evident cyclic manifestation of droughts, coupled with the understanding that they are locally expected, suggests that they, at the very least, should be anticipated; nevertheless, it begs the question: are they predictable? Thus far, these findings indicate an overall differential occurrence of drought across spatial and temporal scales. The following sections address the aforementioned salient questions—namely: (i) How is the phenomenon called drought perceived in Maasai-pastoralism?; (ii) Do the Maasai’s perceptions, concepts, or ideas concerning drought differ from the conventional definition of drought, and if so, in what ways?; (iii) How is drought occurrence, in the Maasai rangelands of southern Kenya, distributed across spatial and temporal scales?; (iv) What are the implications of drought perception (as defined by the Maasai and conventionally) and its spatiotemporal distribution on adaptive capacity of and resource management in indigenous Maasai-pastoralism across these rangelands—and specifically highlight the differences and similarities between and within the data sources,
viz. participatory surveys with those living with the drought (the Maasai) and instrument data.
4.2. Spatiotemporal Distribution of Drought: What Trends and Whose Observations?
Results from the current study reveal corroborative as well as divergent outcomes
vis-à-vis drought years in two specific modes: among the respondents (see
Section 3.2), and between the instrument and the survey data (
Figure 2 and
Figure 4, respectively). With regard to corroboration, the survey data show that over 50% of the Maasai’s households concurred on over 80% of the total observed drought events during the period 1983–2006. This high concurrence among the respondents is indicative of the spatial vastness of drought events, because the sampling was randomized across the district. A strong consensus is also evident among households regarding simultaneous negative anomalies in seasonal rains and the depletion of pastures across spatiotemporal areas and/or the declined productivity of livestock, particularly cattle (
Pv = 100%, N = 120, p < 0.05,
Table 1). This finding indicates the inextricable interconnectedness of climatic, ecological and socioeconomic factors in shaping the system of Maasai-pastoralism. Besides the respondents’ corroboration, a consensus between the instrument and the survey data is evident. For example, at the district level, the majority of the drought years evident via the survey data (over 80% of the events, including the cyclic ones,
Figure 4) strongly matched those derived from the instrument data (
Figure 2a). This strong consensus offers a confirmation that drought
actually occurred during the mentioned years, and is a testament to the Maasai’s knowledge about climatic changes occurring in the region in general, and about drought temporal trends within the district in particular, indicating that the perceptions of these pastoralists are not random. It is also a testament to the Maasai’s capacity to interpret and learn about climatic changes occurring in this resource-variable region, which, from a social perspective, allows them to adjust certain components of their livelihood accordingly. This finding, coupled with the evidence that the Maasai’s knowledge about drought is handed down through generations, indicates that their perception about climatic changes and drought trends draws from both indigenous and local happenings and conditions. Indeed, the components of drought, based on the Maasai’s perception (see
Section 3.2), reveal diverse factors and processes—for example, “failure of rainfall for two consecutive seasons”, “shortage of pasture”, “continual inability to purchase livestock input and/or households’ food”,—and their various interactions, which define the concept of drought. With regard to indigenous climatic knowledge, and from a policy perspective, Luseno
et al. [
49], using the case of pastoralists of the rangelands of northern Kenya and southern Ethiopia, advises that it provides useful insights
vis-à-vis enhancing the feasibility of conventional meteorological forecasts. Therefore, it must be pointed out that policies and practices for enhanced drought management in Maasai-pastoralism and similar production systems need to integrate emic and etic knowledge.
Besides the aforementioned corroboration, a divergence among the Maasai’s households is evident
vis-à-vis the magnitude of the observed droughts. For example, although 1987 was frequently mentioned (>70%) as a drought year, it was assigned a low importance value; in contrast, 2004 was both moderately mentioned (
ca. 50%) and ranked. This means that different households perceived the same event, which looks like the same and homogeneous event via the instrument data, differently: this provides a vital insight and a critical entry point
vis-à-vis policy-makers’ and scientists’ intervention efforts geared toward informed drought management. Continuing with this differential perception, this finding indicates that these two drought events manifested with differing intensities across spatial scales because Maasai households are dispersed across the district; and the study design was randomized. The evident significant temporal and spatial contrasts (
Table 1) further attest to this differential spatial intensity, and so does the analysis via geospatial autocorrelation. With regard to instrument data for specific event analyses via geospatial autocorrelation, drought intensities tracked agroecological zones (AEZ): high-potential AEZs such as around Mount Kilimanjaro [
6] experience mild- to low-intensity drought and
vice versa for low-potential zones such as Magadi (
Figure 3).
The finding suggests that an inhabitant’s location determines his perception about the occurrence and intensity of drought: this can be attributed to the differential drought exposure of critical rangeland resources (CRR)—critical rangeland resources (CRR) are a component of the definition of drought in Maasai-pastoralism—due to the existing variation in environmental spaces, topographic and geological settings, and rainfall that characterize this rangeland. For example, because ecologically high-potential places (e.g., around the
Ol Doinyo Orok Hills:
Figure 3) tend to harbor forage (e.g., pasture for livestock) for longer periods than other places, in such areas a
normal short-term drought, in Maasai terms, could terminate without significantly affecting CRR during that specific year. Consequently, the resident Maasai perceives it as a non-drought year. By contrast, when the drought is spatially widespread, several households simultaneously experience a shortage of CRR, rendering most respondents to perceive such a period as a drought year, and could have designated it as an extreme event, particularly if their socioeconomic sector was impaired significantly. From an ecological perspective, this finding suggests that the manifest diverse environmental spaces, particularly at finer-resolution scales, affect the way the Maasai perceive drought intensity. This understanding sheds light on previously posed salient questions
vis-à-vis the Maasai’s perception of the phenomenon called drought, its occurrence, and its distribution, and the consequent implications of this climatic hazard on the management of CRR. Suffice that to help mitigate the deleterious effects of drought, or to enhance the Maasai’s adaptive capacity to this drought, the external analysts (mainly policy-makers and scientists) need to learn about drought from the affected, and in this manner, the local uptake of policy or research findings is likely to succeed.
The Maasai’s designation and ranking of drought year can also be attributed to the way these pastoralists perceive the manifestation of the phenomenon called drought. Drawing from the Maasai’s perceptions (see
Section 3.2), drought can be summarized as that condition that occurs when the expected seasonal rains are significantly shortened, or are spatially restricted, or are low; causing shortage of pasture and/or water; leading to insufficient nourishment for and output from livestock and/or reduced household socioeconomics; and/or impairing non-Maasai/non-pastoral social and economic landscapes in the region. It is worth noting that, in addition to the location of the affected, drought impacts on cross-scale social and biophysical landscapes influence its characterization.
It must further be pointed out that drought, in Maasai-pastoralism, comprises its meteorological manifestation (e.g., failure of rainfall) and its cross-scale socioeconomic (e.g., continual inability to purchase livestock input and/or households’ food) and environmental impacts (e.g., pasture shortage) (see
Section 3.2). It captures external happenings and conditions, for example the presence of monotonous/lack of vegetables in markets and the failure of crops in farmers’ fields (
Table 1). More specifically, it is founded on various combinations of environmental, social, and economic variables and on spatiotemporal variation of seasonal rains, indicating that drought (pastoralist drought), as perceived through the lens of the Maasai pastoralists, is simultaneously multivariate and multiscalar—this is called
pastoralist drought for the purpose of this study.
The evident variety of variables that define drought among the Maasai (
Table 1) denotes the progression stages of pastoralist drought, particularly when the variables apply to the same event. For example, a drought that occurs due to shortened long-rains alone is less intense compared with one that couples a meteorological event with impaired household socioeconomics. It is worth noting that a reduced amount of rainfall is never construed as a drought occurrence in Maasai-pastoralism (
Table 1): rather, drought in the meteorological sense or as a derivative of rainfall, among the Maasai, is comprised of a delay or failure across spatial and/or temporal scale. This finding indicates, apropos drought as a derivative of rainfall, that spatial extent and timing are more important (they are the most crucial variables), and that amount received has little significance. Also notable is the rare usage (33% of recorded drought variables,
p < 0.05) of meteorological variables alone in defining the manifestation of drought: in fact, non-meteorological variables alone are widely used in defining drought (40% of recorded drought variables,
p < 0.05) in this livelihood production system. This indicates that, when drought creeps in, the Maasais are able to perceive its manifestation on socioeconomic and ecological spaces: these are the crucial dimensions of drought. The high importance attached to defining drought based on the dynamics of meteorological (rainfall) factors alone, the reduction in spatial extent (
65%, Sv ≥ 1.45 ≤ 2.44, p < 0.05), logically implies that some places within the rangeland could be receiving rainfall while, at the same time, other places within the same rangeland could experience a drought condition. This interpretation further highlights the existence of the aforementioned micro-climatic patches within the Maasai’s rangeland of Kenya.
That in this system both altered timing and complete failure of rainfall bear equal importance (
>90%, Sv ≥ 2.45 ≤ 3.00, p < 0.05)
vis-à-vis defining the occurrence of meteorological drought is worth noting. This suggests that the altered timing of rainfall—its delay and/or early termination—has the same effect as complete failure. This interpretation makes sense when taken in the context of reduced pasturage due to land-use change [
6] and, hence, inaccessibility to CRR during periods of drought; here, altered timing leads to the shortage of forage for livestock, with consequent reduced socioeconomic returns on one’s household. Similarly, this explanation makes sense when viewed from phenological perspective: grass tends to sprout quickly upon sensing moisture, and therefore both delay/early termination cause this resource to wither and deplete, and so does a complete failure of rainfall. Thus, the timing of rainfall is critical in Maasai-pastoralism. Collectively, these findings denote the spatial, temporal, social, and environmental dimensions of drought, not only as a climatic event, but also when viewed under the lens of a specific indigenous production system, in this case Maasai-pastoralism. Therefore, policies that anticipate benefiting drought adaptation in Maasai-pastoralism should incorporate the various dimensions of the pastoralist drought.
As among the respondents, a divergence about drought years was also evident between the instrument and the survey data. More specifically, results from the instrument data (
Section 3.1) captured fewer major drought events compared with the analyses of survey data for the same period, indicating a divergence for some drought years between the two data sources. The manifestation of specific years, for example 1987, as having normal conditions via the instrument data (
Figure 2a) and as having drought conditions via survey data (
Figure 4) indicates that some drought events that occurred at the finer scale were undetected at the coarser scale. Thus, for example, the 2004 event (
Figure 2a) was an
average drought condition and a
major drought condition, under instrument data and through the survey data, respectively. The variation in outcome under different data sources can be attributed to the differential intensity with which drought events manifested—or were felt—across spatial scale, and it can be explained using the progression of
conventional drought-types (further details regarding conventional drought types are well documented, especially by established authorities on the subject of drought, for example Dr. Donald Wilhite (see the various citations in this work and elsewhere)) as well as the structural components of the pastoralist drought. More specifically, drought events depicted by the available instrument data are mainly reflective of meteorological drought because they purely draw from recorded precipitation data. Meteorological drought is characterized by an extended period of below-average amounts of absolute rainfall [
14], and is partially silent on other drought types, for example
socioeconomic drought. It should be noted that conventional drought types are distinguished based on certain identifiable characteristics [
14,
50,
51], which is beyond the scope of this paper, and therefore will not be explicated upon. In contrast, pastoralist drought goes beyond capturing most of the attributes of the conventional drought types to include various cross-scale environmental, climatic, and socioeconomic components. It is pointed out that the Maasais’ perception of meteorological drought differs from the conventional interpretation of the same: it excludes rainfall amounts (
Table 1). This revelation further highlights the contextual understanding of drought, in this case between the instrument and the survey data. The findings further suggest that, whenever it occurs, pastoralist drought affects numerous facets of Maasai-pastoralism over timescales. This is unlike the implication of the isolated manifestation of any of the conventional drought types. Clearly, pastoralist drought is simultaneously a climatic as well as an ecological and social phenomenon, and it is multiscalar and multifaceted. This is not entirely unexpected, because climatic knowledge, including that of drought, among the indigenous inhabitants, particularly across the rangelands of East Africa, has predominantly been shaped by specific livelihood needs, by trends of the rainfall, and by one’s location [
49], all of which vary with changes occurring across scales. This variation becomes conspicuous in highly heterogeneous ecozones that the Maasai rangelands comprise: suffice that to manage or monitor a meteorological component of the same based on instrument data is only partially informative
vis-à-vis enhancing the Maasai’s drought-adaptive capacity and CRR management.
Same Location, Different Drought: Insights from the Field
Apropos these last points, from the structural components of the pastoralist drought, it should be evident that Maasai pastoralists perceived and rated the occurrence of drought based on pasture and water needs as well as the local spatiotemporal trend of the seasonal rains, rather than on the amounts alone and the intensity of the aridity of the dry season. Therefore, it is plausible that because 1987 was preceded by a relatively dry year, the CRR—mainly water and pastures—were still inadequate for the livestock, and, thus, the Maasai perceived it as a drought year. Similarly, although the instrument data depicted 1994 as an extreme drought year—having a magnitude that was almost akin to that of 1984—it was a period of moderate drought from the perspective of the Maasai. This is plausibly because it was preceded by non-drought conditions, showing that pastoralist drought accounts for the legacies of the precedent conditions rather than solely the present situation. Unlike the pastoralist drought, conventional droughts rarely focus on the timing of the event, but rather dwell mainly on the average amounts of rainfall received [
49] with scant focus on systems and/or sectors affected.
Moreover, conventional drought is predominantly buttressed by
documented events. In fact, in its presently influential synthesis of climate change literature, the Intergovernmental Panel on Climate Change (IPCC) [
9] (p. 986) defines drought as, “The phenomena that exist when precipitation has been significantly below normal
recorded (i.e., documented) levels, causing serious hydrological imbalances that adversely affect land resource production systems (emphasis mine).” Although this definition simultaneously captures various conventional drought types, particularly meteorological, hydrological, and socioeconomic droughts, it begs two key questions: first is the contribution of the non-
recorded precipitation-events—particularly in a region where droughts occur frequently and technology for recording such events is infrequently utilized. Unlike in the West (e.g., National Drought Mitigation Center, (NDMC), Lincoln, NE, USA), historical events for this region are scantily documented, and where such records exists is on an
ad hoc, even accidental, basis; however, these historical records remain held in living repositories—the Maasai themselves—and are passed down through generations through diverse narratives [
6].
The second question concerns that utilization of
normal recorded levels in a region (ASAL) where precipitation is highly variable across spatiotemporal scales. With regard to the rangelands of Africa, conventional drought is only partially informative
vis-à-vis addressing the need of the indigenous pastoralists (who are the main inhabitants) and where most pastoralist drought goes unrecorded and where precipitation is highly variable. Note that in rainfall-dependent pastoralism, the spatial extent and timing of rainfall is more crucial than its amounts [
49]; this is because pastures are adapted to low amounts of rainfall, and, therefore,
ceteris paribus, this form of Maasai-pastoralism can still operate viably under dry non-drought conditions. Clearly, the usage of the recorded meteorological drought alone is less useful
vis-à-vis informing development policies toward enhancing the resilience of the Maasai-pastoralism in the region.
This is not to dispel the usefulness of conventional drought types. Rather, it is to highlight that the usage of a single drought type
per se to inform drought management in these rangelands is insufficient
vis-à-vis offering comprehensive assessment of availability of the CRR. Indeed, conventional meteorological drought has been useful for informing drought management at the coarser scales; for example, the government of Kenya and various development agencies rely on this drought type to gauge food security in the region, although indirectly [
7]. From the current empirical evidence—particularly that in Maasai-pastoralism
meteorological drought is construed as rainfall delay/failure across spatial and/or temporal scale, and never its reduced amount—it logically translates that effective usage (and hence informed drought and resource management) of meteorological drought should incorporate both the perceptions of those living with drought and derivations from the instrument data. From a policy perspective, coarser-scale instrument data and analyses provide meaningful proxies, particularly in approximating the manifestation and effects of drought impacts and risk to livelihoods, but information derived from the same is only partly informative
vis-à-vis the design of effective drought and resource management policies geared toward enhancing the resilience of the drought-prone ASAL pastoralists. Similarly, it is also plausible that because the applicability of local and indigenous knowledge is more attuned to happenings and conditions at the finer-resolution scale, it is also partially informative
vis-à-vis the availability of CRR at the coarse scale. This becomes more important under conditions of vast and intense droughts when households are forced to move their livestock to unaffected regions [
6]. In isolation, local/indigenous knowledge is unlikely to inform effectively on potential herding destinations for the Maasai during periods of droughts. In policy terms, the findings indicate that knowledge about drought affects the way the manifestation of this climatic hazard is perceived, communicated, and characterized.
Taken together, these findings reveal that drought in the Maasai rangelands of Kenya is simultaneously a social/biophysical construct and a reality. Therefore, policies that anticipate improving drought-adaptive capacity and management of CRR among the Maasai should utilize local and indigenous knowledge alongside the available conventional data. This necessity becomes more crucial for informing drought adaptation under the current state of drought occurrences as well as in relation to the projected intensified occurrence of this climatic hazard as the climate continues to change.
4.3. The Changing Climate: Implication on the Dynamics of Drought Occurrences
Thus far, it should be clear that, although drought is a recurrent climatic hazard across the Maasai rangelands, the manifestation of a cyclic and shortened return period is not. Note that, unlike for decadal droughts, the potential forcings of biennial droughts are rarely documented (even undocumented), and so are the causes of the shortened return period of this climatic hazard. However, some of the forcings of decadal droughts are known. For example, existing studies on the rainfall for eastern Africa have often associated the occurrence of extreme droughts with specific teleconnections with ENSO [
46,
47], mainly La Niña. Having said this, and given the evidence presented in the current study, some salient questions can be put forward: (i) Is the region experiencing more influence from this global phenomenon than before? (ii) Has the trend of ENSO or other triggering forcings changed? (iii) Is the changing climate generating these undocumented happenings, and if so, by what mechanism? Apropos this last question, one logical pathway by which the changing climate could trigger these happenings is by altering the dynamics of these forcings. It is thus plausible that the extreme drought that plagued the region in 2009 [
4] and the recent (2015) manifestation of extreme rainfall [
5] are signatures of such altered dynamics. The challenge for future research is, therefore, to examine the interlinked effects of ENSO, drought, and climate change across spatial and temporal scales. The currently documented drought events (this paper) spans over 70 years—and, indeed, well above the established 30-year average of weather for discerning change in climate [
48]—which provides sufficient initial data to contribute to such an effort. From a climatic perspective, it is plausible that the observed biennial and shortened return period for drought is an indicator of a changing climate. The IPCC [
9,
10] projects a climate change–induced increased occurrence of drought (climatic/meteorological drought) globally. With regard to the Maasai rangelands of East Africa, mixed projections—with uncertainty in both increases and decreases—dominate, e.g., [
11,
52]; however, increased occurrences of extreme events, both severe droughts and flood-inducing rainfall, are expected for Kenya [
52].
It should be noted that, with regard to concerns relevant to the rangelands of Africa, numerous studies have corroboratively concluded that, as the climate changes, the frequency with which drought occurs, its duration, and its spatial extent will increase relative to the present conditions (
ibid.). This scenario could devastate the ASALs in ways never experienced before. This is because the ASALs of Africa are extremely sensitive to changes in climate [
12]. In fact, a slight change in the climate has the capacity to significantly amplify the intensity and the frequency with which extreme climatic events (e.g., extreme drought) manifest in these ASALs (
ibid.). With reference to the Maasai rangelands, this
slight change in climate could translate to intensified occurrences of the currently frequent, widespread, cyclic, and temporally clustered droughts. Consequently, a future of extreme, prolonged, spatially extensive, and recurrent pastoralist droughts could be a regular happening across these rangelands—a
new normal trend, just as the way regular droughts are presently normal, might evolve. Thus, the currently observed extreme events, for example that seen in 2005 (
Figure 2 and
Figure 4), could become the norm. In fact, the devastative drought of 2009 [
4] followed this extreme event on its heels. It is emphasized that, although indigenous pastoralists across the ASAL of East Africa regard drought as a normal occurrence [
43,
44], it is plausible that they do so conditionally on their unhindered tracking of CRR and availability of adequate forage for their livestock. This is no longer the case.
Like similar pastoralism in the region, Maasai’s tracking of CRR—particularly pasture—across the region is being hindered by frequent occurrences of drought (e.g.,
Section 4.1, [
6]) and, like similar livelihoods in the region, by multiple cross-scale social and biophysical pressures [
39,
40]. This situation could intensify as the climate changes and as the various drivers of socioeconomic globalization permeate into the Maasai social and biophysical landscapes, thereby deconstructing and/or disrupting the geography of resource management in Maasai-pastoralism.
Having said this, a crucial unanswered question is whether Maasai pastoralists have the time and/or opportunity to adjust to altered climatic and/or non-climatic conditions and happenings. Thus far, whether the increased occurrences of drought (this paper), in concert with increased variability in the recorded rainfall for East Africa’s rangelands [
44,
45], coupled with the multiple cross-scale human and biophysical factors within which socioecological systems are embedded [
53], will accommodate Maasai-pastoralism in the present rangeland is rarely explored. Studies that anticipate enhancing the management of CRR, the adaptive capacity of the Maasai, and/or the feasible subsistence on Maasai-pastoralism, as well as other inhabitants of rangelands who subsist on climate-sensitive production systems, should account for cross-scale social and biophysical factors, their processes, and their interactions.
4.4. Spatiotemporal Distribution of Drought: Implications on Key Sectors of Maasai-pastoralism
The observed occurrence of drought including its differential manifestation across spatial and temporal scales and in its intensity has various ecological, socioeconomic, and policy implications
vis-à-vis the availability of CRR, the adaptive operation of the Maasai-pastoralism in this rangeland, and the consequent adaptive capacity of the Maasai to drought and to other non-drought factors. Like in similar ASALs, the occurrence of drought in the Maasai rangelands depletes grass and even defoliates some woody plants, thereby reducing vegetation density and foliage cover (
Figure 5). From this study, it is evident that several drought events occurred across the region. The increased occurrences and/or intensity of droughts due to the changing climate [
10,
11] could exacerbate the magnitude with which vegetation density and foliage cover is altered. This could reduce the composition, abundance, recovery, and/or the productivity of certain plant forms and/or species, hamper rainfall infiltration capacity, and expose soil to agents of erosion, reducing soil fertility and altering the productivity of such environments.
In ecological terms, the evident manifestation of temporally clustered drought events reduces the availability of the already variable CRR that characterize this rangeland. The occurrence of consecutive droughts, particularly when they include an extreme drought, reduces vegetation density and its recovery, impairs establishment of pasture—for example, through the now-shortened growth season—and enfeebles the productive potential of the environment. Such droughts can also reduce the recharge and flow of water into the various water reservoirs, thereby occasioning water shortages for both human and livestock needs. It is pointed out that this impairment of environment productivity does not necessarily translate to the blighted function of other vital ecosystem attributes, as is the case with desertification [
54]; they could remain unhindered since rangelands are highly resilient to various short-term disturbances.
In addition to these short-lived effects, the manifestation of recurrent droughts could cause long-lasting impacts, however. For example, consecutive drought events inhibit the continuous establishment of palatable natural grass and/or encourage invisibility of unpalatable plants (
Figure 5) across spatial (e.g., from ecosystem to landscape level) and temporal scales (e.g., from ephemeral to long resident species/forms). Inhibited establishment of pasture in such spaces translates to the prolonged reduction of forage for the Maasai’s livestock, and the consequent reduction of yields from these animals, ultimately impairing households’ socioeconomic conditions. Existing studies shows that drought impacts on rangelands (e.g., depletion of pasture) translates to impaired productivity of these environments, which leads to insufficient nutritional supply for livestock [
55,
56], leading to impaired socioeconomics of the pastoralists. In sum, climatic-induced encroachment of invasive plants—and the alteration of forage cover and/or compositions of other species and/or forms— reduces the productivity of the Maasai’s livestock by encroaching upon the potential pasture spaces, thereby reducing the amount of forage that is extractable.
The deleterious effects of consecutive droughts, especially when they encompass an extreme drought, can also have a lasting deleterious impact on the socioeconomic status of a household, for example if a family loses most of or its entire herd of livestock because of the persistent shortage of pasture. These interpretations also suggest that the occurrence of consecutive droughts pre-exposes and hampers recovery of the ecological and the socioeconomic facets of the Maasai-pastoralism to the next drought event in the cluster. Clearly, drought has the capacity to occasion cascading and cumulative deleterious effects on the ecological and the socioeconomic facets of Maasai-pastoralism. Most importantly, these consecutive droughts occur against a backdrop of multiple livelihood risks—for example, conflicts, livestock and human disease, and water and pasture shortage—that regularly confront pastoralists across East Africa [
6,
22,
24,
39,
40]. Therefore, consecutive droughts do not only hamper the ecological and socioeconomic recovery from the preceding drought event, but they also disrupt the viable operation of Maasai-pastoralism in the rangelands. This diminishes the adaptive capacity of the Maasai to drought hazard as well as to other livelihood risks. The manifestation of extreme and/or consecutive droughts suggests that these pastoralists are experiencing a threat to their very survival. Climate change–induced, intensified occurrence and the spatial extent of drought, (e.g., [
10,
11,
52]) will reinforce the manifestation of these conditions and happenings.
The evident differential spatial coverage of drought spaces (
Figure 3 and
Figure 4) is a plausible indicator of the intensity with which pasture is depleted. It should be noted that the intensity of drought does not necessarily equal the consequent rate of forage depletion. Existing studies have shown that, in the rangelands, variability in annual vegetation production is
ca. 50% higher than corresponding variability in annual rainfall on locations receiving less than 600 mm [
57]. Given this, and given that the dynamics of pasture within the ASALs strongly track the trends of precipitation [
58] and that much of what Kajiado receives is on the rims of this amount,
is it plausible that a meteorological drought of moderate intensity is environmentally and hence socioeconomically devastative on Maasai-pastoralism and similar livelihoods in these rangelands than would be projected via occurrence of meteorological drought alone? The differential coverage by drought suggests that different drought events occasion divergent impacts. The evident irregular mosaics of these drought spaces across timescales indicate the shifted intensity of droughts, and provide clues about the availability of pasture. It specifically indicates the shifted heterogeneity of pasture across timescales and the differential shortage of this critical land resource during periods of drought.
For example, the evident patches of the persistently mild to no-drought (
ca. −0.5–0.0) condition around Mount Kilimanjaro and the Namanga Hills (
Figure 3) indicate areas where pasture and other vegetation forms are unaffected, or mildly affected, by drought. Drought intensities tracked agroecological zones—high-potential zones such as around Mount Kilimanjaro experience mild to low-intensity drought, mainly normal drought from the Maasai’s perspective, and
vice versa for low-potential zones such as Magadi—translate to variable availability or depletion of CRR.
The evident manifestation of intense drought conditions in areas of low agroecological potential (e.g., Magadi) and
vice versa for higher agroecological spaces (e.g., around the Chyulu Hills and Mount Kilimanjaro) (
Figure 3), respectively, indicate the plausible shortage of CRR, particularly forage, or its availability thereof. It is pointed out that the availability of CRR does not translate into its accessibility: much of these spaces are privately owned and under protected and fortressed wildlife sanctuaries [
6], and therefore have higher odds of inaccessibility for the Maasai’s livestock.
Apropos variable availability or depletion of CRR, and
ceteris paribus, because high-potential zones harbor more leafy woody species than low-potential zones, it translates to the persistent availability of browse forage for the Maasai’s browsing livestock (mainly goats); therefore, a household rearing more goats than cattle or sheep (grazers) will be able to exploit such spaces during periods of drought. Thus, rearing goats in these rangelands enhance one’s adaptive capacity. Moreover, the former livestock species has higher odds of thriving even under drought condition because graminoids deplete at a faster rate than woody species (both trees and shrubs), and because goats are more adapted to drylands than the current breeds of the Maasai’s cattle and sheep: a situation explaining why cattle and sheep register high mortality during periods of drought [
6]. The converse applies for areas of persistent patches of intense drought, for example within Magadi. The manifestation of these mosaics of drought spaces further confirms the diversity of ecoclimatic zones in this rangeland. The projected intensified occurrence and spatial coverage of drought alongside proliferation of aridity [
9,
10,
11] could expand the extent of the currently arid and semi-arid spaces and reduce the extent of the present transitional semi-humid–semi-arid agroecological zones, and plausibly diminish the humid spaces altogether. This, collectively, could lead to reduced heterogeneity of critical land resources that characterize this rangeland and occasion widespread and simultaneous shortage of forage for the Maasai’s livestock across scales. Note that this manifests against a backdrop of reducing the spatial extent of pastoral land due to the permeation of pressures from socioeconomic globalization, for example agriculture encroachment, access-restricted wildlife sanctuaries, and land privatization (
Figure 6), on the present ASAL zones of the Maasai land. In fact, over 40% of the land area under the semi-arid agroecological zone was lost to agriculture encroachment alone between the 1970s and the 1990s across the pastoral districts of Kenya [
7], which include all the country’s Maasai land.
These land-use types were carved out of formerly communal Maasai land, a situation that has been occasioned by shifts in land tenure and the subsequent sub-division of lands. Tenurial changes are traceable in policies and programs of the British colonial authority, of the post-colonial government of Kenya, and of the collaborative efforts of Kenya’s administration and development agencies that operate under the aegis of the various bilateral and multilateral partnerships, in that order, over temporal scale, which altered land tenure to start with [
16,
59,
60,
61]. In addition, data from the wider project revealed that the sale of some of the Maasai’s lands to private users, both Maasai and non-Maasais [
6]. This is an undertaking that serves to reinforce changes in the land tenure systems, with an overall loss of tracts of Maasai land, and by extension, a loss of access to the various CRR contained therein. Taken together, the findings of this study suggest that drought is only partially influential in dictating the availability of CRR among the Maasai in the rangelands of southern Kenya, and that simultaneous alteration by cross-scale social, climatic, and environmental factors dictates the availability of CRR, the adaptive operation of Maasai-pastoralism, and, ultimately, the drought-adaptive capacity of these pastoralists. Thus, it is clear that availability and accessibility of CRR is simultaneously influenced by drought and human and environmental factors.
From a drought adaptation and ASAL resource management perspective, locations that are persistently unaffected by this climatic hazard are indicative of spaces that harbor dependable sources of forage during periods of drought in Kajiado; and, if accessible, such spaces can offer refuge for the Maasai’s livestock during periods of drought. From a policy perspective, initiatives for practical alleviation of pasture shortage toward enhanced adaptive capacity of the Maasai should be hinged upon an understanding of the multiple and cross-scale challenges of accessing these climatically and ecologically spatiotemporally diverse spaces that contain CRR. Therefore, the need for mainstreaming drought adaptation into land-use policies cannot be overemphasized.