Elephant distribution around a volcanic shield dominated by a mosaic of forest and savanna (Marsabit, Kenya)

We investigated the factors that influenced the distribution of the African elephant around a volcanic shield dominated by a mosaic of forest and savanna in northern Kenya. Data on elephant distribution were acquired from four female and five bull elephants, collared with satellite-linked geographical positioning system collars. Based on the eigenvalues (variances) of the correlation matrix, the six factors that contributed significantly to high total variances were distance from drinking water (24%), elevation (15%), shrubland (10%), forest (9%), distance from settlements (8%) and distance from minor roads (7%), contributing to 73% in the observed variation of the elephant distribution. The elephants were found at high forested elevations during the dry season but they moved to the lowlands characterized by shrubland during the wet season. Elevation acts as a proxy for the vegetation structure. The presence of elephants near permanent water points (13%) and seasonal rivers (11%) during the dry and wet seasons, respectively, demonstrates that water is the most important determinant of their distribution throughout the year. We conclude that the distribution of elephants in Marsabit Protected Area and its adjacent areas is influenced mainly by drinking water and vegetation structure.     

The numbers and distribution of elephant Loxodonta africana in the Rwenzori National Park and Chambura Game Reserve, Uganda

A series of aerial counts of elephant made between 1968 and 1972 in the Rwenzori National Park and Chambura Game Reserve, Uganda, is described. A summary is included of all previous aerial counts made in the region. Numbers present in the park since 1963 averaged 1752 during the dry seasons, some 3/5 of the wet season mean of 2896. Corresponding figures for the reserve are 325 and 501. The distribution was very significantly aggregated for each count and remained so when the totals for all counts were lumped. The distribution tended to be more aggregated in dry than in wet seasons. The overall density in the park was 1.43 elephant km-² with wet and dry season means of 1.74 and 1.05 respectively. Corresponding figures for the reserve are 2.06, 2.42 and 1.57 km-². The mean group size in the park was 6.3 elephant but there were significant variations over the whole range of observations although not between wet and dry season means. The elephant in the reserve were highly aggregated with a mean group size of 28.8. It is concluded that there was a significant rise in the wet season population of the park between 1963 and 1968 but that subsequently, numbers remained fairly stable. Numbers in the dry season and in the reserve at all seasons have not varied significantly since 1963. It is suggested that the wet season rise has been due to a reduction in the area of grazing land available outside the park at this time of year. It is concluded that vegetational differences are responsible for the un even distribution of elephant with human disturbance having an effect in some areas. It is believed that in the region censused, there are at least three distinct populations of elephant of which only that in the reserve is showing signs of stress.     

Elephant spatial use in wet and dry savannas of southern Africa

The influence of elephants on woody vegetation cover varies from place to place. In part this may be due to the way elephants utilize space across landscapes and within their home ranges in response to the availability and distribution of food. We used location data from 18 cows at six study sites across an east to west rainfall gradient in southern Africa to test whether wet- and dry-season home-range sizes, evenness of space use within seasonal home ranges and range overlap between seasons and between years, differed between wet and dry savannas. We then tested whether the quantity, distribution and seasonal stability in vegetation productivity, a coarse measure of food for elephants, explained differences. Elephants in wet savannas had smaller wet- and dry-season home ranges and also returned to a higher proportion of previously visited grid cells between seasons and between years than elephants living in dry savannas. Wet-season home-range sizes were explained by seasonal vegetation productivity while dry-season home-range sizes were explained by heterogeneity in the distribution of vegetation productivity. The influence of the latter on dry-season home ranges differed among structural vegetation classes. Range overlap between seasons and between years was related to inter-seasonal and inter-annual stability in vegetation productivity, respectively. Evenness of elephant spatial use within home ranges did not differ between savanna types, but it was explained by seasonal vegetation productivity and heterogeneity in the distribution of vegetation productivity during the wet season. Differences in elephant spatial use patterns between wet and dry savannas according to vegetation structure and season may need to be included in the development of site-specific objectives and management approaches for African elephants.     

Elephants caught in the middle: impacts of war, fences and people on elephant distribution and abundance in the Caprivi Strip, Namibia

We conducted wet [26 March–4 April 2003 (Apr03)] and dry [1–8 November 2005 (Nov05)] season aerial surveys of African elephants ( Loxodonta africana Blumenbach) in the Caprivi Strip, Namibia to provide an updated status report on elephant numbers and distribution and assist with a historical analysis of elephant distribution and abundance in the Caprivi Strip. During the wet season when water was available in seasonal pans, elephants were widely distributed throughout the survey area. In contrast, during the dry season, a majority of elephant herds occurred within 30 km of the perennial Kwando, Linyanti and Okavango rivers and few herds occurred within the West Caprivi Game Reserve where water in the seasonal pans was limited. We estimated 5318 elephants for the 7731-km² survey area (0.71 elephants km⁻²) for the Apr03 wet season survey and 6474 elephants for the 8597-km² survey area (0.75 elephants km⁻²) for the Nov05 dry season survey. Based on our aerial surveys and reports of elephant numbers and distribution from historical aerial surveys and telemetry studies, civil war, veterinary fences and human activities appear to have effected changes in African elephant abundance, distribution and movements in the Caprivi Strip, Namibia since 1988 when the first comprehensive aerial surveys were conducted.     

Seasonal habitat use by Elephants (Loxodonta africana) in the Mole National Park of Ghana

To avoid unnecessary waste of limited resources and to help prioritize areas for conservation efforts, this study aimed to provide information on habitat use by elephants between the wet and dry seasons in the Mole National Park (MNP) of Ghana. We compiled coordinates of 516 locations of elephants’ encounters, 256 for dry season and 260 for wet season. Using nine predictor variables, we modeled the probability of elephant's distribution in MNP. We threshold the models to “suitable” and “nonsuitable” regions of habitat use using the equal training sensitivity and specificity values of 0.177 and 0.181 for the dry and wet seasons, respectively. Accuracy assessment of our models revealed a sensitivity score of 0.909 and 0.974, and a specificity of 0.579 and 0.753 for the dry and wet seasons, respectively. A TSS of 0.488 was also recorded for the dry season and 0.727 for the wet season indicating a good model agreement. Our model predicts habitat use to be confined to the southern portion of MNP due to elevation difference and a relatively steep slope that separates the northern regions of the park from the south. Regions of habitat use for the wet season were 856 km² and reduced significantly to 547.68 km² in the dry season. We observed significant overlap (327.24 km²) in habitat use regions between the wet and dry seasons (Schoener's D = 0.922 and Hellinger's‐based I = 0.991). DEM, proximity to waterholes, and saltlicks were identified as the key variables that contributed to the prediction. We recommend construction of temporal camps in regions of habitat use that are far from the headquarters area for effective management of elephants. Also, an increase in water point's density around the headquarters areas and selected dry areas of the park will further decrease elephant's range and hence a relatively less resource use in monitoring and patrols.     

Response of African Elephants (Loxodonta africana) to Seasonal Changes in Rainfall

The factors that trigger sudden, seasonal movements of elephants are uncertain. We hypothesized that savannah elephant movements at the end of the dry season may be a response to their detection of distant thunderstorms. Nine elephants carrying Global Positioning System (GPS) receivers were tracked over seven years in the extremely dry and rugged region of northwestern Namibia. The transition date from dry to wet season conditions was determined annually from surface- and satellite-derived rainfall. The distance, location, and timing of rain events relative to the elephants were determined using the Tropical Rainfall Measurement Mission (TRMM) satellite precipitation observations. Behavioral Change Point Analysis (BCPA) was applied to four of these seven years demonstrating a response in movement of these elephants to intra- and inter-seasonal occurrences of rainfall. Statistically significant changes in movement were found prior to or near the time of onset of the wet season and before the occurrence of wet episodes within the dry season, although the characteristics of the movement changes are not consistent between elephants and years. Elephants in overlapping ranges, but following separate tracks, exhibited statistically valid non-random near-simultaneous changes in movements when rainfall was occurring more than 100 km from their location. While the environmental trigger that causes these excursions remains uncertain, rain-system generated infrasound, which can travel such distances and be detected by elephants, is a possible trigger for such changes in movement.     

Relationship between group dynamics and spatial distribution of African elephants in a semi‐arid environment

Group dynamics related to distribution of African elephants in the semi‐arid environment of Tsavo East National Park, Kenya was studied between 2007 and 2010. I examined the seasonal distribution of lone bulls, bull groups, family units and mixed groups and group size. Lone bulls were widely distributed in the dry season and localized in the wet season, whereas bull groups were localized in both seasons. On average bull group size did not differ with seasons or areas, but larger groups were observed in preferred areas in the dry season. Family units were widely distributed in the dry season and localized in the wet season, whereas mixed groups were localized in both seasons. Although family units and mixed groups tended to be large in all areas in the wet season, large groups were also observed in the dry season. Large family units were widely distributed, whereas large mixed groups were localized. The relationship between group dynamics and distribution was attributed to the combination of social, ecological and poaching factors. This study provided insight into distribution patterns that can be applied to the security of the Tsavo elephant population.     

Elephant survival,rainfall and the confounding effects of water provision and fences

Elephant are increasing across some areas of Africa leading to concerns that they may reduce woodlands through their feeding. Droughts may help limit elephant numbers, but they are generally both episodic and local. To explore more general impacts of rainfall, we examine how its annual variation influences elephant survival across ten sites. These sites span an almost coast-to-coast transect of southern Africa that holds the majority of the ~500,000 remaining savanna elephants. Elephants born in high rainfall years survive better than elephants born in low rainfall years. The relationship is generally weak, except at the two fenced sites, where rainfall greatly influenced juvenile survival. In these two sites, there are also extensive networks of artificial water. Rainfall likely affects elephant survival through its influence on food. The provision of artificial water opens new areas for elephants in the dry season, while fencing restricts their movements in the wet season. We conclude that the combination of these factors makes elephant survival more susceptible to reductions in rainfall. As a result, elephants living in enclosed reserves may be the first populations to feel the impacts of global warming which will decrease average rainfall and increase the frequency of droughts. A way to prevent these elephants from damaging the vegetation within these enclosed parks is for managers to reduce artificial water sources or, whenever practical, to remove fences.     

The ranging patterns of elephants in Marsabit protected area,Kenya: the use of satellite‐linked GPS collars

We investigated the ranging patterns of elephants in the Marsabit protected area, north eastern Kenya, to ascertain the range of bachelor and female family herds in different seasons, and to identify corridor and noncorridor areas. Data were acquired for five bachelor and four female family herds equipped with satellite‐linked geographical positioning system collars, and monitored from December 2005 to December 2007. Distinct dry (about 260 km²) and wet seasons (about 910 km²) ranges were observed, with connecting corridors (north‐eastern corridor: about 90 km long, about 2‐7 km wide; southern corridors: about 10‐20 km long, about 2‐3 km wide). The dry season range corresponded with Marsabit evergreen forest, while the wet season range matched with dry deciduous lowland shrubs. The ranging elephants moved at speed of about 0.2‐20 kmh^?1. Bachelor herds moved faster than female family herds. Elephants moved fast during the intermediate and wet seasons than during the dry season. The speed of ranging elephants was over 1 kmh^?1 in the corridor areas and about 0.2 to less than 1 kmh^?1 in the non‐corridor areas. Expansion of settlements towards corridor areas needs to be controlled to avoid future blocking of connectivity between wet and dry season elephant ranges.     

Landscape-scale habitat response of African elephants shows strong selection for foraging opportunities in a human dominated ecosystem

Balancing trade-offs between foraging and risk factors is a fundamental behavior that structures the spatial distribution of species. For African elephants Loxodonta africana, human pressures from poaching and conflict are primary drivers of species decline, but little is known about how elephants structure their spatial behavior in the face of human occupancy and predation. We seek to understand how elephants balance trade-offs between resource access, human presence and human predatory risk factors (poaching and conflict killing) in an unfenced, dynamic ecosystem where elephants persist primarily outside protected areas in community rangelands. We used tracking data from 101 elephants collected between 2001 and 2016. We investigated elephant behavior in response to landcover, topography, productivity, water, human features and human predation risk using third-order resource selection functions. We extended this analysis by employing a mixed-effects multinomial regression to identify temporal shifts in habitat use, and evaluated temporal shifts in movement patterns by estimating mean squared displacement across different productivity periods. Across periods, elephants displayed strong selection for productive areas and areas near water. Temporal shifts in habitat use showed that, during the dry period, elephants were clustered around permanent water sources where humans also congregated. At the onset of the wet period, a shift occurred where elephants moved away from permanent water and from permanent settlements towards seasonal water sources and seasonal settlements. Our findings indicate that foraging and water access are important limiting factors affecting elephants that potentially restrain their spatial responses to humans at the scale of our analysis. Given that pastoralists and elephants rely on the same resources, increasing human and livestock populations enhance pressure on shared resources and space in Africa's drylands. The long-term conservation of elephants will require approaches that reduce poaching as well as landscape level planning to prevent negative impacts from increasing competition for preferred resources.     

Elephant (Loxodonta africana) footprints as habitat for aquatic macroinvertebrate communities in Kibale National Park,south‐west Uganda

This is the first study where elephant footprints as habitat for aquatic macroinvertebrate communities were assessed. Preliminary observations during the dry season in Kibale Forest, Uganda, indicated that water‐filled footprints constituted the majority of stagnant ponds. Consequently, this study aimed at giving an overview of the diversity and ecology of those habitats and the capacity of elephants as ecosystem engineers. The fauna and abiotic factors (age, size, substrate, organic matter, pH, canopy cover, temperature, conductivity) of 30 water‐filled natural elephant footprints were sampled, resulting in the record of 61 morphospecies among 27 families/orders. Species composition was dominated by Hydrophilidae and Dytiscidae and influenced by environmental variables, such as age and organic matter. To study the colonization process, 18 artificial footprints were created within different distances from the water source. After 5 days, 410 specimens were collected, with higher species richness in artificial footprints closer to a natural water source. We conclude that colonization of water‐filled footprints is fast, they constitute important habitats with high diversity and variability, and they act as stepping stones for dispersal and add to the ability of elephants as ecosystem engineers. We emphasize the importance of elephants as a key species in ecosystem dynamics and conservation practice.     

Sexual segregation in habitat use by elephants in Chobe National Park, Botswana

We report on a study conducted on free‐ranging African elephants in the woodlands of northern Botswana. We compared bull groups and family units with regard to (1) their patterns of habitat use and (2) their ranging distances from perennial water sources. During the dry season, adult males frequented more habitat types than family units, whereas family units used a wider diversity of habitats than bulls during the wet season. Bulls roamed widely (>10 km) from perennial drinking water in the dry season, when family units congregated within 3.5 km of the rivers. During the wet season, when ephemeral pans were abundant, all elephant groups were found at intermediate distances (5 km) from the rivers. The spacing of elephants in the dry season is consistent with sexual segregation but we reject the hypothesis that this is an outcome of indirect competition for food, because our concurrent studies on elephant feeding ecology found no evidence for intraspecific competition. Instead, we propose that most adult male elephants space themselves to avoid conflict with musth bulls and roam widely in the dry season between discretely distributed feeding ‘hotspots’. The small proportion of males that are in musth remain close to family units to maximize mating opportunities, and family units are unable to range far from water in the dry season. This is due to (1) comparatively high rates of water turn‐over among juveniles and lactating cows and (2) the reduced mobility of neonates.     

Spatio-Temporal Distribution of Injured Elephants in Masai Mara and the Putative Negative and Positive Roles of the Local Community

Background

Very few studies have ever focused on the elephants that are wounded or killed as local communities attempt to scare these animals away from their settlements and farms, or on the cases in which local people take revenge after elephants have killed or injured humans. On the other hand, local communities live in close proximity to elephants and hence can play a positive role in elephant conservation by informing the authorities of the presence of injured elephants.

Methodology/Principal Findings

Between 2007 and 2011, 129 elephants were monitored in Masai Mara (Kenya), of which 54 had various types of active (intentionally caused) or passive (non-intentionally caused) injuries. Also studied were 75 random control samples of apparently unaffected animals. The observed active injuries were as expected biased by age, with adults suffering more harm; on the other hand, no such bias was observed in the case of passive injuries. Bias was also observed in elephant sex since more males than females were passively and actively injured. Cases of passive and active injuries in elephants were negatively related to the proximity to roads and farms; the distribution of injured elephants was not affected by the presence of either human settlements or water sources. Overall more elephants were actively injured during the dry season than the wet season as expected. Local communities play a positive role by informing KWS authorities of the presence of injured elephants and reported 43% of all cases of injured elephants.

Conclusions

Our results suggest that the negative effect of local communities on elephants could be predicted by elephant proximity to farms and roads. In addition, local communities may be able to play a more positive role in elephant conservation given that they are key informants in the early detection of injured elephants.     

长江中下游岸带(宜昌-铜陵段)湿生植物的群落构建机制研究

沿长江中下游（宜昌-铜陵段）13座城市共37个位点,分别于丰水期和枯水期对岸带的湿生植物进行调查,从物种和系统发育2个维度研究群落的构建机制,并结合环境和空间因子探讨其驱动因素。结果显示：（1）丰水期湿生植物群落的α多样性高于枯水期,且丰水期α多样性主要与水分条件呈正相关,而枯水期则主要与温度和土壤总氮含量有关。（2）丰水期的系统发育结构指数呈聚集趋势,暗示生境过滤起着主导作用,而枯水期的NRI（net relatedness index）和NTI（nearest taxon index）呈不同趋势,暗示存在近期的群落分化。（3）群落的α多样性在物种层面和系统发育层面存在显著关联性,其多样性水平可在一定程度上互为表征。（4）长江中下游沿岸湿生植物群落的构建机制在不同时期存在差异,丰水期的群落构建是环境筛选和扩散限制共同作用的结果,且以环境筛选作用占主导,而枯水期的群落构建仅在物种层面受一定程度环境筛选作用的影响。（5）大生境的温度变化、微生境的土壤水分和养分条件是影响长江中下游岸带湿生植物群落差异的主要驱动因素。该研究结果可为长江中下游岸带湿地生态系统的管理和保护提供科学支持。     

A population survey of forest elephants (Loxodonta africana cyclotis) in northern Congo

From February to April of 1989 transects were run in four forested areas of northern Congo (Brazzaville) to census elephant populations using dung counts. A total of 401.0 km of line transects was completed during the survey. An overall extrapolated density of 0.7 elephants/km² was obtained with a variation from 0.3 to 0.9 elephants/km². This study shows for the first time that elephants occur in high densities in a number of sites in northern Congo. When elephant dung density is plotted against distance from the nearest village for each transect a significant positive linear correlation results. Based on this correlation we hypothesize that the population of elephants in much of northern Congo is high. Local reports and our own observations indicate that elephant poaching is heavy in northern Congo and that the CITES ban on trade in African elephant ivory has had a limited effect on the level of poaching.     

Diet and distribution of elephant in the Maputo Elephant Reserve, Mozambique

The distribution and diet of the elephants of the Maputo Elephant Reserve were studied using dung counts, satellite tracking and faecal analysis. The results were compared with earlier data from before the civil war in Mozambique. The elephant population decreased during the civil war, but 180 animals still remain. Earlier studies described the elephants as preferring the grass plains. Currently, the elephants prefer the dense forest patches over the high quality forage found in the grass plains. Water salinity affected distribution; elephant dung piles were found closer to fresh water in the dry season. A total of 95 different plant species were identified in the faeces. The percentage of grass was relatively low compared with other studies, increasing at the beginning of the rainy season. At the end of the dry season, elephants concentrated on the few available browse species with young leaves, but generally preferred grass species to browse species. Diet composition was mainly affected by season and less by habitat. The elephants have changed their habitat preference in reaction to poaching, and probably increased the contribution of browse species in the diet. The presence of forest patches has been vital for the survival of the elephants.     

Human settlement drives African elephant (Loxodonta africana) movement in the Sebungwe Region,Zimbabwe

Understanding the key drivers that influence the potential distribution of herbivore species in changing landscapes has been at the centre of enquiry in wildlife science for many decades. This knowledge is particularly important for keystone species like the African elephant (Loxodonta africana) whose population is declining even in conservation areas. The Sebungwe Region is part of the Kavango‐Zambezi Transfrontier Conservation Area and supports ~4,000 elephants. The Sebungwe Region has lost an estimated 76% of its elephant population over the years. This study aimed to determine how the elephant distribution in the Sebungwe Region was affected by human settlement and whether the patches for elephant distribution were large enough for elephant habitation. The prediction of the potential distribution of the elephant was based on presence‐only data modelled through an ensemble algorithm that combined several candidate models to enhance predictive ability. We observed that human settlement drives the potential distribution of elephants in the Sebungwe Region (test AUC = 0.95), and patches from the model were on average <1.5 km². Our results provide initial insights into the key habitat factors that drive distribution of elephants in the Sebungwe landscape. Future conservation of the elephant could benefit from our study through systematic planning of settlements, which might help minimise human interaction with wildlife.     

How do African elephants utilize the landscape during wet season? A habitat connectivity analysis for Sioma Ngwezi landscape in Zambia

1. The influence of environmental factors on the distribution and persistence of African elephants (Loxodonta africana) is pertinent to policy makers and managers to formulate balanced plans for different land‐use types.
2. The study focuses on movement of elephants and how they utilize foraging areas in Sioma Ngwezi landscape in Zambia by answering the following questions: (1) Which environmental variables and land‐cover class predict the movement of elephants during the wet season in Sioma Ngwezi landscape? (2) What is the wet season suitable habitat for elephants in Sioma Ngwezi landscape? (3) What are the major wet season movement corridors for elephants in Sioma Ngwezi landscape?
3. We used GPS telemetry data from the collared elephants to assess habitat connectivity. Maximum entropy (MaxEnt) and linkage mapper were the tools used to predict habitat suitability, movement corridors, and barriers in the landscape during the wet season.
4. The study identified elevation, land cover, and NDVI as the most important environmental predictors that modify the dispersal of elephants in the landscape during the wet season. Additionally, a total of 36 potential wet season corridors were identified connecting 15 core areas mainly used for foraging and protection from poachers in the landscape. Of these, 24 corridors were highly utilized and are suggested as priority corridors for elephant movement in the landscape.
5. The identified wet season habitats and functional corridors may help to combat elephant poaching by patrolling areas with high relative probability of elephant presence. The findings may also help abate human–elephant conflict such as crop‐raiding by managing identified corridors that run into agriculture zones in the game management area.

     

云南思茅亚洲象对栖息地的选择与利用

以思茅市境内栖居的一个由5 头雌象(3 头成年体, 1 头亚成体, 1 头幼体) 组成的象群为研究对象, 利用痕迹追踪、样线调查和村庄调查等方法对野生亚洲象的栖息地选择和行为进行了初步研究。在栖息地中共记录到野生高等植物457 种, 组成5 种植被类型。旱季象群的活动区域面积是35.67 km² , 该活动区域中有3 个核心活动区, 面积分别是3.65 km² , 2.79 km² 和3.29 km² , 象群对此3 个活动核心区域循环利用; 在旱季亚洲象经常取食19种野生植物, 其中主要取食的有8 种, 还取食7 种农作物, 对农作物有一定依赖性, 这种依赖的程度随着农田周围森林中野生食物丰富程度的增加而降低; 在季雨林中亚洲象主要取食的植物种类最丰富。雨季象群的活动区域面积是18.42 km² , 该区域中只有1 个核心活动区, 面积9.08 km² 。雨季亚洲象只取食5 种野生植物, 另取食5 种农作物, 农作物为其雨季主要食物。研究结果表明, 思茅地区亚洲象栖息地中的野生食物可能不足, 人类活动对亚洲象的生存干扰较为严重, 亚洲象的行为表现出对栖息地内食物条件和人类干扰的适应。建议尽快遏止日益严重的栖息地片断化趋势, 恢复自然植被并为亚洲象提供充足的野生食物是保护该物种的关键。     

Can mineralization of soil organic nitrogen meet maize nitrogen demand?

Background and aims

It is generally assumed that very large herbivores, such as elephants, make foraging decisions at large spatial scales, but the extent to which seasonal foraging decisions are driven by soil quality, and its link to plant nutrient levels, is uncertain.

Methods

We studied the diet selection of African elephants Loxodonta africana in Ithala Game Reserve in northern KwaZulu-Natal, South Africa, using data on elephant feeding preferences and spatial distributions from a published paper. Elephants were present in the eastern half with granite soils in the wet season, and in the western half with sedimentary soils in the dry season. The quality of these two soil types and of seven key tree species for elephants was assessed in both seasons.

Results

Soil quality was higher on the sedimentary soils in terms of total nitrogen, soil respiration, water-holding capacity, organic carbon and pH. Leaf quality was higher on the sedimentary soils in the dry season, while in the wet season there was no significant difference in leaf quality of the seven key tree species growing on the two substrates.

Conclusion

Soil quality may explain elephants’ foraging decisions in the dry season, but not in the wet season. Elephants preferred trees with higher protein and lower concentrations of fibre on both granite and sedimentary soils.