Recent Historical Changes Research Articles

Quantitative Historical Change in Bumblebee (Bombus spp.) Assemblages of Red Clover Fields

BackgroundFlower visiting insects provide a vitally important pollination service for many crops and wild plants. Recent decline of pollinating insects due to anthropogenic modification of habitats and climate, in particular from 1950's onwards, is a major and widespread concern. However, few studies document the extent of declines in species diversity, and no studies have previously quantified local abundance declines. We here make a quantitative assessment of recent historical changes in bumblebee assemblages by comparing contemporary and historical survey data.Methodology/Principal FindingsWe take advantage of detailed, quantitative historical survey data from the 1930's on bumblebee (Bombus spp.) abundances and species composition in red clover (Trifolium pratense) fields, an important floral resource and an attractant of all bumblebee species. We used the historical survey data as a pre-industrialization baseline, and repeated the same sampling protocol at nearly the same localities at present, hence setting up a historical experiment. We detected historical changes in abundances (bees/m2) of both workers (the “pollinatory units”) and queens (effective population size), in addition to species composition. In particular, long-tongued bumblebee species showed consistent and dramatic declines in species richness and abundances throughout the flowering season of red clover, while short-tongued species were largely unaffected. Of 12 Bombus species observed in the 1930's, five species were not observed at present. The latter were all long-tongued, late-emerging species.Conclusions/SignificanceBecause bumblebees are important pollinators, historical changes in local bumblebee assemblages are expected to severely affect plant reproduction, in particular long-tubed species, which are pollinated by long-tongued bumblebees.

CLIMATE CHANGE IN THE WESTERN CAPE OF SOUTH AFRICA: TRENDS, PROJECTIONS AND IMPLICATIONS FOR CHILL UNIT ACCUMULATION

The Western Cape region of South Africa, a major producer of deciduous fruit, has been identified as highly vulnerable to climate change. Climatic trends were analysed on a monthly basis for 12 rural meteorological stations across the region for the period 1967 to 2007. Significant warming trends were found for midto late-summer and end-winter to spring for daily minimum temperature (Tmin), and for mid-summer, autumn and spring for daily maximum temperature (Tmax). Chill unit accumulation has decreased significantly, particularly in autumn. Air temperatures are predicted to increase by a further 1-2°C within the next 30 years, together with decreasing rainfall especially in autumn/winter. An analysis of possible impacts of regional projections of climate change on deciduous fruit production was conducted, with the emphasis on chilling accumulation and dormancy in apples. The warmer or otherwise more marginal production areas, and high chill cultivars are likely to be the first to experience negative impacts of warming. INTRODUCTION Global climate change is occurring as evidenced by warming of average air and ocean temperatures, melting of snow and ice, and rising sea level (IPCC, 2007). Mediterranean-climate regions worldwide have been identified as highly vulnerable to climate change (Baldocchi and Wong, 2006), including the Western Cape region of South Africa (Midgley et al., 2005). Climate projections for fruit regions for 2030-2040 include warming by 1-2°C, reductions in frontal autumn and winter rainfall, and a contraction of the winter season (Hewitson et al., 2005). Apples are generally grown under conditions of insufficient winter chilling; this necessitates the use of chemical rest-breaking treatments to achieve satisfactory budburst, fruit set, yield, and fruit quality (Cook and Jacobs, 2000). In the event of climate warming, we expect that accumulation of chill hours will decrease, eventually reaching a critical threshold at which apple production would no longer be commercially sustainable in currently marginal areas. However, the rate of decline in chill hours could vary intra-seasonally, with different phenological results, and between colder and warmer production areas. We set out to analyze recent historical regional-scale changes in temperature and chill accumulation, predicted reductions in chill accumulation with future warming, and implications for fruit production, particularly apples. MATERIALS AND METHODS Recent Historical Temperature and Chill Unit Trends in the Western Cape Quality-controlled data for twelve meteorological stations throughout the Western Cape of South Africa (Fig. 1) were obtained from the division AgroMet of the Institute for Soil, Climate and Water, Agricultural Research Council, South Africa, for the period 1967-2007. The stations are spread throughout the climatically divergent fruit-growing regions. Daily minimum (Tmin) and maximum (Tmax) air temperatures, and monthly means of Tmin and Tmax were used. Langkloof Experimental Farm was excluded due to closure in Proc. IX IS on Orchard Systems

‘Realising the Self and Developing the African’: German Immigrants in Namibia

This paper is based on research among German immigrants in Namibia, a country with a long history of colonisation. After Germany, the first colonial power, ceded the territory as a consequence of the First World War, South Africa effectively ruled the country until 1990. Both former colonial powers established principles of white rule and initiated settler communities, whose descendants still live in the country. This article examines biographical narratives of German immigrants who have settled in Namibia since the 1950s. It focuses on their discourses of self-understanding in this postcolonial, post-apartheid context. The discussion follows two related issues: the cultural models of personhood that narrators use to represent their historical selves, and the ways in which these models are applied to recent historical change in Namibia. The article concludes by showing how both perspectives work to recycle colonial imaginations.

The Changing Trends of Modern Teaching

There is no doubt that our role as teachers is undergoing one of its most significant changes in recent history. Teachers no longer need to be physically present, and the traditional classroom size and schedules are becoming less important with availability of classes on the Internet. From providers

Using Historical Linguistics to Describe Polynesian Ethnomycology1

Descriptions of human and plant interactions at a local, regional, and global level drive the need for ethnobotanists to use tools from a variety of disciplines including paleoethnobtany, historical ecology, phylogenetics and historical linguistics. The comparative method from historical linguistics was used in this study to test the hypothesis: fungi were an important resource used by Polynesian peoples in the past, with little change in recent history. A comprehensive literature search of ethnographical works was undertaken to collate the various Polynesian terms for fungi. Corresponding terms for fungi, or cognates, were used to reconstruct words from the Proto Polynesian language, based on regular sound changes. Of the 117 terms for fungi found in 23 Polynesian languages, 25 cognates were used to reconstruct four (4) Proto Polynesian terms: three life form folk taxa *talinga, *seka and *limu and one folk generic *talinga kimoa. These Proto Polynesian terms were then compared to the modern lexicon to discuss the spatial and temporal use of fungi in Polynesia. Differences in the number of modern terms and evidence of binomials indicate changes in the perception and use of fungi in at least two cultures, New Zealand Mori and Marquesan. Results also suggest a wide distribution of the folk generic centered on the scientific genus Auricularia. Evidence of only one folk generic with morphological associations and a lack of subordinate folk taxa suggest that fungi were not a culturally salient resource to the Proto Polynesian peoples. Nevertheless, the presence of terms for macro fungi suggests obvious gross patterns of stem habit and bodily form were recognized. There are major limitations when using historical linguistics to describe the use of resources including the requirement for well recorded and closely related languages. Working with a linguist and encouraging researchers to ask more in-depth questions will go some way to combat these limitations. Further research is needed in the Cook Islands, Samoa, and the Marquesas to develop a clearer understanding of fungi as a resource in Polynesia.

Igbo professional migratory orders, hometown associations and ethnicity in the USA

AbstractIn this article I examine ethnographically the discursive means by which Igbo speakers in hometown associations in the USA are crafting lives and communities abroad to express a territory‐bound sense of ethnic group membership. I contend that Igbo speakers living abroad are undergoing a process of ethnic formation or ethnification that is structured by increased rates of immigration and recent historical and political change in Nigeria. In response to these events, shifting representations of self and group identity incur an essentialist quality from abroad. Such essentialism is a paradoxical earmark of globalization for the brain‐drain Igbo professional.

Trends and multidecadal oscillations in rainfall extremes, based on a more than 100‐year time series of 10 min rainfall intensities at Uccle, Belgium

Investigation was made on whether the recent historical changes in frequency and amplitude of rainfall extremes can be considered statistically significant under the hypothesis of no trend or temporal clustering of rainfall extremes. The analysis was based on a 107‐year time series of 10‐min Peaks‐Over‐Threshold rainfall data obtained from the Uccle station in Belgium. Rainfall intensities were aggregated at levels ranging from 10 min to the monthly scale, and defined for different seasons and block lengths between 5 and 15 years using sliding windows. Perturbations in rainfall extremes were derived, which represent the empirical quantile changes. Significant deviations in rainfall quantiles were found, which persisted for periods of 10 to 15 years. In the winter and summer seasons, high extremes were clustered in the 1910s–1920s, the 1960s and recently in the 1990s. This temporal clustering highlights the difficulty of attributing “change” in climate series to anthropogenically induced global warming. Research in a variety of climate phenomena is essential for the attribution of changes in the climate.

Strategic Choices and Unintended Consequences: Employer Militancy in Victoria's Meat Industry, 1986-93

Concepts of strategic choice have become widely used in industrial relations, particularly as methods of understanding recent historical changes. While the operation of strategy-choosing relative to implementation has generated debate, there has been little discussion of how strategic choices can generate unintended consequences even where there are no apparent weaknesses in implementation. We discuss these issues in the context of under-explored areas of Australian labour history: the history of industrial relations in Victoria's meat industry and employer activity in the meat industry more generally. Our focus is the creation, by employers, of an intense, industry-wide struggle with the union and, in particular, their choices regarding terrains and methods for that struggle. Using a narrative approach, we explore important unintended consequences that flowed from the interaction of employer-strategising in product and labour markets. These, in turn, generated paradoxical outcomes, given employers' original objectives.

Copper, zinc and lead impact in SW Iberian shelf sediments: An assessment of recent historical changes in Guadiana river basin

In the present study, lithogenic/biogenic and anthropogenic elements were determined in five sediment cores collected at the SW Iberian Continental Shelf in order to investigate the spatial and temporal heavy metal distribution and to associate them with specific continental influences/events. Elemental concentrations suggest a heavy metal (Cu, Zn and Pb) enrichment at the upper sections of all the cores. This enrichment is larger for cores localised closer to the coastline and probably exposed to a stronger continental influence. The geochemical regional background values for the studied elements are reached at ∼25-30 cm for all the studied cores with one exception (core 8), which showed to be metal-enriched down to ∼80 cm. It is worthnoting that core 8 is located closer to the coastal area, in a different fine sedimentary deposit, in which the deposition rates seem to be considerably higher. Enrichment factors (EF) calculated by using the natural background value determined at the deeper layers show that the EF values vary at the upper sections of cores, between 1.0 and 4.5 and the spatial distribution of the sediment cores show a similar behaviour in the heavy metal distribution patterns along this area of the continental shelf. Cu, Zn and Pb are heavy metals associated with mining exploitation along the Iberian Pyrite Belt, one of the most important mining areas of southwestern Europe, with massive orebodies of these metals. The combination of enrichment factors downcore profiles with sedimentation rate values signifies the beginning of heavy metal pollution in shelf sediments (∼200-250 years ago) and is coincident with the mining exploitation reactivation during the XIX century.

Assessment of soft-bottom polychaete assemblages in the Gulf of Lions (NW Mediterranean) based on a mesoscale survey

Ninety-two stations (10, 20, 30, 40 and 50 m depth) located on 21 inshore–offshore transects between the French–Spanish border and the mouth of the Rhône River were sampled during the 1998 Fall. Their polychaete fauna was analyzed to: (1) describe the distribution pattern of polychaete assemblages at the scale of the whole Gulf of Lions, (2) identify the relationships between these assemblages and the main environmental parameters, (3) establish a link between these assemblages and the benthic communities already described for Northwestern Mediterranean, and (4) assess recent historical changes in trends in densities and α diversity between assemblages. Three polychaete assemblages were identified using cluster analysis and associated procedures. These assemblages were tightly associated with depth and sediment granulometry as indicated by the concordance between their spatial distributions and the sedimentary map of the Gulf of Lions. Assemblage I contained most of the 10 and 20 m deep stations and was associated with littoral fine sands. Assemblage I was found all over the Gulf of Lions and was characterized by high abundance and high biomass due to the presence of large numbers of the serpulid Ditrupa arietina. Assemblage II was mostly composed of 30 m deep stations and was associated with littoral sandy mud. Assemblage II was dominated by the lumbrinerid Lumbrineris latreilli. It was composed of two sub-assemblages (IIa and IIb) in relation with sediment granulometry. Sub-assemblage IIb was associated with finer sediment than sub-assemblage IIa. Sub-assemblage IIa was only found in the Southern part of the Gulf of Lions, whereas sub-assemblage IIb was mostly found in the Northern part of the Gulf of Lions. This pattern is probably indicative of the sedimentation of fine particles originating from the Rhône River at intermediate depth as suggested by: (1) the sedimentary map of the Gulf of Lions, and (2) the outputs of recent models of sediment transport in the Gulf of Lions. Assemblage III was composed of 40 and 50 m deep stations; it was associated with terrigeneous coastal mud and found all over Gulf of Lions. Assemblage III was dominated by the sternaspid Sternaspis scutata. These three assemblages were tightly related with the benthic communities already described independently by Picard [Picard, J.,1965. Recherches qualitatives sur les biocénoses marines des substrats meubles dragables de la région marseillaise. Recueil des Travaux de la Station Marine d'Endoume 52, 1–160] and Guille [Guille, A., 1971b. Bionomie benthique du plateau continental de la côte catalane française. II – Les communautés de la macrofaune. Vie et Milieu 21, 149–280] based on samples collected along the Provençal and the French Catalan rocky coasts, respectively. Unfortunately, no quantitative data were available to compare the α-diversity of the three newly defined assemblages with historical data collected by these two authors. We therefore compared our diversity measurements with the data collected by Desbruyères et al. [Desbruyères, D., Guille, A., Ramos, J.M., 1972/73. Bionomie du plateau continental de la côte catalane espagnole. Vie et Milieu 23, 335–363] in the Bay of Rosas (Spanish Catalan coast). Due to differences in the sampling effort between the two studies, this comparison was restricted to trends between assemblages. Our results show maximal densities and minimal α-diversity in the Littoral Fine Sand assemblage, which was not the case in Desbruyères et al. [Desbruyères, D., Guille, A., Ramos, J. M., 1972/73. Bionomie du plateau continental de la côte catalane espagnole. Vie et Milieu 23, 335–363]. Major temporal changes obviously reflect the increases of Ditrupa arietina (in the Littoral Fine Sands assemblage), and to a lesser extent Lumbrineris latreilli (in the Littoral Sandy Mud assemblage).

Namaqualand's climate: Recent historical changes and future scenarios

A brief outline of some issues concerning global climate change research is presented before discussing local-scale changes in Namaqaland's rainfall. Using a gridded data set derived through interpolation of station records, trends in observed rainfall for the period 1950–1999 are discussed. To assess what changes may occur during the 21st century, the downscaled results of six different General Circulation Model projections are presented. The historical trends show some clear spatial patterns, which depict regions of wetting in the central coastal belt and the north-eastern part of the domain, and extensive drying along the escarpment. Reasonably good agreement is shown by the different downscaled projections. These suggest increased late summer convective precipitation in the north-east, but extensive drying along the coast in early and mid winter consistent with the poleward retreat of rain-bearing mid-latitude cyclones.

Greek Zombies

This paper explores the possibility that the human mind underwent substantial changes in recent history. Assuming that consciousness is a substantial trait of the mind, the paper focuses on the suggestion made by Julian Jaynes that the Mycenean Greeks had a “bicameral” mind instead of a conscious one. The suggestion is commonly dismissed as patently absurd, for instance by critics such as Ned Block. A closer examination of the intuitions involved, considered from different theoretical angles (social constructivism, idealism, eliminativism, realism), reveals that the idea of ‘Greek zombies’ should be taken more seriously than is commonly assumed.

An evaluation of two GCMs: simulation of North American teleconnection indices and synoptic phenomena

We evaluate the ability of two coupled atmospheric–oceanic GCMs—the Hadley Center's third generation coupled climate model (HadCM3) and the Canadian Center for Climate Modeling and Analysis second-generation coupled model (CGCM2)—to simulate the North Atlantic Oscillation (NAO), the Pacific North American teleconnection pattern (PNA), and map patterns in the Midwest region of the United States, relative to NCEP/NCAR reanalysis (NNR) data. The observed (NNR-derived) and GCM-derived probability distributions and temporal behavior of the daily teleconnection indices exhibit agreement over the 1990–2001 reference period, and both GCMs successfully reproduce the range of 500-hPa map patterns over the study region. During the reference period, observed and modeled map patterns are similar in terms of frequency, coherence, persistence, and progression, although the most common map pattern occurs too often in HadCM3 relative to NNR and CGCM2-derived map patterns generally exhibit closer agreement with those derived from NNR data. Despite the relatively high degree of correspondence between the observed and simulated teleconnection indices and map patterns in the study area, differences between the GCM and NNR-derived map-pattern frequencies in the reference period are greater than either (1) recent historical changes in map-pattern frequencies or (2) changes in the map-pattern frequencies as derived from twenty-first century GCM simulations, indicating that changes in these phenomena over recent and approaching decades are of insufficient magnitude relative to model uncertainty to be definitively identified. Copyright © 2005 Royal Meteorological Society.

One World … One Telephone: Iridium, One Look at the Making of a Global Age

The global has become an important, but sometimes amorphous conceptual category in understanding recent historical change for a range of literatures—including those pertaining to postmodernism, globalization, and science and technology studies. This article attempts to offer one empirical reference point on how conceptions of the global entered into one of the signature technology and business ventures of the 1990s: Iridium, a pan‐national corporation initiated by Motorola to provide worldwide cellular telephony via satellites and handheld mobile phones.

Wildland–urban interface: Challenges and opportunities

The wildland–urban interface (WUI), commonlydescribed as the area where urban areas meet andinteract with rural lands (Vince et al., 2005), includesthe edges of large cities and small communities, areaswhere homes and other structures are intermixed withforests and other land uses, and islands of undevel-oped lands within urban areas (Alavalapati, 2005;Monroe et al., 2003; SAF, 2004). The interface isparticularly characterized by areas of urban sprawlwhere development pressures are pressed againstpublic and private wildlands. Continuous transitionof land-use, primarily from agriculture and forest usesto urban land uses, in the interface raises a myriad ofsocioeconomic and environmental concerns. A deeperunderstanding of these concerns is essential toformulate effective policy solutions.While a household’s dream of home ownership andthe value placed on private property rights favor urbandevelopment (Garkovich, 2000), the moving interfaceassociated with urbanization poses a series of chal-lenges to both rural and urban communities. Theseinclude ecosystems fragmentation, increased exposureto invasive species, water and air pollution, wildfires,and loss of habitat for wildlife. These changes affectresidents of rural and urban areas, natural resourcemanagers, and business and environmental organiza-tions. For example, management of forests for eco-logical goods and services such as forest products andcleanwaterisaffectedbypeopleoccupyingtheforests.Manytypesoflandownershipsintheinterfacebringindnew neighborsT with a different set of values, life-styles,andlandethicsintotheinterface;andasaresult,conflicts and tensions arise between these dnewT anddexistingT communities and cultures. The changesimparted as the WUI develops are not only significantbutareveryrapid,muchfasterthananyotherprocessesthat impacted land use changes in recent history. Forexample, Alig et al. (2000) noted that as much as 14million acres of non-industrial forests were lost tourban use between 1952 and 1997. Multiple jurisdic-tions and scales within a region, that are typical of aWUI, can further complicate efforts to manage andconserve natural resources. Thus, the rapid urbangrowth in wildland has significant and widespreadsocial, cultural, economic, and environmental implica-tions. Addressing the problems of the WUI to sustainecologically viable and socio-economically feasiblelandscapesisacomplextaskforwhichneithereasynorperfect solutions exist (Alavalapati, 2005).Planning and managing in a WUI thus invariablyinvolvesseveraldisciplinesthatencompassthenatural,socio-economic, and cultural dimensions of the issues,

Genetic changes associated to declining populations ofFormicaants in fragmented forest landscape

We monitored populations of two wood ant species, Formica aquilonia and Formica lugubris, through annual mapping of the colonies in a fragmenting forest landscape from 1966 to 1998. The genetic population structure was studied at the end of the study period by using 12 microsatellite loci. Fragmentation of forest led to a decline and spatial redistribution of populations. Changes in the spatial distribution were particularly pronounced in the highly polygynous (many queens in a single nest) species F. aquilonia, whose local populations declined or became extinct, or relocated themselves and colonized new patches. The genetic relationships of the remaining subpopulations indicated the historical developments, revealing the boundaries of the historical populations (high values of genetic differentiation, F(ST)), recolonization histories (genetic affinities revealed by Bayesian analyses) and population decline (reduced variation). Big genetic differences could be detected over short distances, so differentiation also depended on social factors. Our results showed that a genetic study can be reliably used to dissect the recent historical changes underlying the present population structure, and that species with different social structures can respond differently to habitat changes. Combining our demographic and genetic results suggests that habitat fragmentation forms a clear threat on a local scale with large negative effects on ant population viability.

Family structure, intergenerational mobility, and the reproduction of poverty: Evidence for increasing polarization?

A substantial body of research has demonstrated links between poverty and family structure from one generation to the next, but has left open key questions about the implications of these associations for aggregate-level change. To what extent does intergenerational inheritance affect trends in poverty and single parenthood over time and, in particular, trends in the relative economic positions of single-parent and two-parent families? This article examines how patterns of intergenerational inheritance play out in the population over the long run, using data from the National Longitudinal Surveys and a model of population renewal that takes into account intergenerational mobility and differential fertility across groups that are defined by poverty status and family structure. Our results suggest that current rates of intergenerational inheritance have little effect on population change over time. They account for only a small share of the recent historical change in poverty and family structure and play no role in exacerbating existing economic disparities by family structure.

Estimated biological variation of the mature human milk fatty acid composition

We estimated the biological variation (CV biol) of 28 fatty acids (FA) in 465 mature human milk samples from The Netherlands, Caribbean, Jerusalem, Tanzania and Pakistan, by using data from the observed variation (CV obs) and analytical variation (CV anal). CV biol of the various regions was remarkably similar. The average CV biol of 455 samples, Pakistan excluded, ranged from 12.7% for 16:0 and 18.9% for 18:1ω9 to 68% for 22:6ω3 and about 100% for 20:5ω3. Those of 20:4ω6, 18:2ω6 and 18:3ω3 were 28.0, 33.0 and 37.3%, respectively. Because of the large CV biol and the many dietary changes in recent history, it seems impossible to consider the present human milk FA composition as the ‘gold standard’ for infant formula. Optimal human milk FA composition should rather derive from populations that consume traditional diets or from the scientific data that show the function of the individual FAs in neonatal development.

Use of floodplain sediment cores to investigate recent historical changes in overbank sedimentation rates and sediment sources in the catchment of the River Ouse, Yorkshire, UK

Floodplain sediment cores collected from seven sites in the catchment of the River Ouse, in Yorkshire, UK, have been used to provide information on recent historical changes in both rates of overbank sedimentation and sediment sources. The environmental radionuclides 137 Cs and unsupported 210 Pb have been used to establish chronologies for each core and to estimate average sediment accumulation rates for the last ca. 30 and 100 years, respectively. Average sedimentation rates for the individual cores ranged from 0.11 to 1.04 g cm −2 yr −1. In all but one case, the estimates of average sedimentation rate during the last ca. 30 years for the individual cores are broadly similar to those for the last ca. 100 years, suggesting that overbank sedimentation rates have been essentially uniform over the longer time period. Composite fingerprints, based on a combination of geochemical and mineral magnetic properties, and a numerical mixing model have been used to investigate downcore changes in sediment source. In the case of source type, most of the cores reflect a primarily topsoil source, although there have been periods with increased contributions from subsoil/channel bank sources. Within the Ouse basin in general, the period commencing in the late 19th and early 20th century and extending through to the 1960s, was characterised by increased contributions from topsoil sources. However, contributions from subsoil/channel bank sources have increased over the last few decades. The source tracing results relating to sediment contributions from the three main geological/topographic zones are in broad agreement with the proportion of the area of the catchment underlain by each rock type. Temporal variations in the contributions from the three geological/topographic zones vary from site to site, but for the lower reaches of the River Ouse contributions from areas underlain by Permian and Triassic rocks, which mainly outcrop in the Vale of York, have increased since the turn of the century. The changes in sediment source identified are probably a reflection of changes in land use and management (and possibly changes in climate). These results enable estimates of contemporary suspended sediment fluxes and sources to be placed into a historical context and provide a means of considering the likely impact of potential future changes in land use and climate in the study basin.

Recent historical climate change and its effect on land use in the eastern part of West Africa

There are indications that low rainfall, drought periods and famine become more frequent in West Africa. This may in part be a rather early expression of the effect of global warming but it is very likely that local factors such as drastic changes in land cover due to expanded cultivated area, as required by a growing population, play an important role. Before studying the causative mechanisms of climate change, it first needs to be established that climate did indeed change significantly, and if so, its nature, extent and magnitude have to be quantified. To this effect time series of annual rainfall (1950–1992) for 42 synoptic climate stations in eastern West Africa, covering 5 countries, were analyzed. The data were subjected to several statistical tests for the entire time series and parts thereof. The outcomes were interpolated in a GIS environment to assess the spatial pattern of change. The time series and spatial analysis reveals that climate change is indeed significant in the northern part of the study area and that the degree of change shows a spatial pattern that can be related to the weather system in combination with topography. A remarkable feature is that the change in rainfall is not a gradual one, but consists of a trend break with zero trend before and after the break. This is unexpected because it might imply that causal factors have to be sought under those that do not change gradually. The year of occurrence of the break is around 1970 but varies in time, again according to a geographic pattern. The reduction of rainfall shortens the length of the growing period (LGP) and has a considerable impact on potential crop yields and their variability. The paper shows the serious implications of recent historical climate change for land use in the semi-arid region of West Africa.