The Effect of Small Scale Topographic Gradient on the Distribution and Community Utilization of Indigenous Woody Species in a Lowland Dryland Environment, Lokapel Area, Turkana, Kenya

The landscape of Lokapel is characterized by a distinctive dryland vegetation, whose distribution is influenced by altitudinal change and the use of woody species by the local community along 100 m altitudinal gradient from River Turkwel (662 m) to Lokapel Hill (764 m). The paper undertakes the following: (a) to establish the influence of elevation on woody vegetation species distribution in different landscapes in the area and (b) to assess the consumptive and non-consumptive uses of woody vegetation in the area by the local community and determine the utility patterns along the altitudinal gradient. A total of forty three species of woody plants were identified with the top five species in terms of widespread distribution being;Indigofera cliffordearia (10 percent), Acacia tortilis (9.8 percent), A. nubica (8.8 percent), Balanites rotundifolia (6.3 percent), and Acacia reficiens (5.4 percent). The local people used the indigenous woody species to address a total of 18 demands including provision of livestock fodder, household construction, bio-energy, and herbal medicines. The variation in woody species and their uses showed the total number of woody species distribution has the highest peak around 680 m but altitude accounted only for 51 percent of the variation in woody species.

典型农林复合系统氮素平衡污染与管理研究

采用田间试验、定位监测和参与式农户调查等方法,研究了农林复合系统氮素平衡和非点源污染特征。结果表明,目前旱地和整个农田子系统氮素略有盈余,水稻田和复合系统有少量亏缺,林地亏缺较大。而20世纪60年代农田氮素严重亏缺,水土流失是产生亏缺的主要原因。模型评价表明,旱地和水稻田目前的氮素平衡基本合理,但化肥施用的剧增已导致农田气态氮素释放以及地表水和地下水非点源污染风险的增加。研究显示,林地极大地减轻了系统水土流失,促进了氮素在各系统间的合理分配。合理施肥、保护林地、实施水保耕作和完善养分管理政策体系是减少农业氮素非点源污染的重要途径。

基于高光谱反射率的喀斯特地区土壤重金属锌元素含量反演

针对传统土壤重金属锌元素含量测定效率低下和喀斯特地区山高坡陡土壤样品采集难度大,亟需先进手段获取土壤重金属锌元素含量的要求,以喀斯特流域为研究区,利用电感耦合等离子质谱测定土壤样品的锌元素含量和分光光广度计采集土壤光谱数据。将所测定的原始光谱,经过连续统去除、一阶、二阶微分、倒数、倒数对数、倒数对数一阶、倒数对数二阶微分7种数学变换,基于高光谱吸收重金属元素的特征吸收带初步判断光谱特征变量,利用相关分析进一步筛选特征变量,运用逐步回归最终确定有效建模光谱变量。采用非线性和线性算法,揭示光谱敏感波段反射率与重金锌元素含量之间的映射关系,进行土壤重金属含量估测。结果表明:基于耦合的光谱特征变量甄选方式,锌元素的特征波段580,810,1410,1910,2160,2260,2270,2350,2430 nm与铁氧化物、有机质、粘土矿物吸收带关联,表明一定程度上捕捉到喀斯特地区土壤重金属锌元素的光谱吸收特性;运用随机森林、支持向量机、偏最小二乘3种算法进行元素含量与光谱变量建模后,采用决定系数和均方根误差评价模型精度。从光谱变换形式和模型性能二个维度综合判断,基于二阶微分变换的随机森林算法准确度最高,为最佳估算模型。通过高光谱反射率估测重金属锌元素含量,实现了喀斯特地区土壤重金属锌元素含量的高效快速反演,为喀斯特地区重金属元素含量动态监测提供了可靠的技术支撑。

Formula for calculating spatial similarity degrees between point clouds on multi-scale maps taking map scale change as the only independent variable

The degree of spatial similarity plays an important role in map generalization, yet there has been no quantitative research into it. To fill this gap, this study first defines map scale change and spatial similarity degree/relation in multi-scale map spaces and then proposes a model for calculating the degree of spatial similarity between a point cloud at one scale and its gener- alized counterpart at another scale. After validation, the new model features 16 points with map scale change as the x coordinate and the degree of spatial similarity as the y coordinate. Finally, using an application for curve fitting, the model achieves an empirical formula that can calculate the degree of spatial similarity using map scale change as the sole independent variable, and vice versa. This formula can be used to automate algorithms for point feature generalization and to determine when to terminate them during the generalization.

Spatio-temporal patterns of satellite-derived grassland vegetation phenology from 1998 to 2012 in Inner Mongolia, China

Spatio-temporal variations of vegetation phenology, e.g. start of green-up season（SOS） and end of vegetation season（EOS）, serve as important indicators of ecosystems. Routinely processed products from remotely sensed imagery, such as the normalized difference vegetation index（NDVI）, can be used to map such variations. A remote sensing approach to tracing vegetation phenology was demonstrated here in application to the Inner Mongolia grassland, China. SOS and EOS mapping at regional and vegetation type（meadow steppe, typical steppe, desert steppe and steppe desert） levels using SPOT-VGT NDVI series allows new insights into the grassland ecosystem. The spatial and temporal variability of SOS and EOS during 1998–2012 was highlighted and presented, as were SOS and EOS responses to the monthly climatic fluctuations. Results indicated that SOS and EOS did not exhibit consistent shifts at either regional or vegetation type level; the one exception was the steppe desert, the least productive vegetation cover, which exhibited a progressive earlier SOS and later EOS. Monthly average temperature and precipitation in preseason（February, March and April） imposed most remarkable and negative effects on SOS（except for the non-significant impact of precipitation on that of the meadow steppe）, while the climate impact on EOS was found to vary considerably between the vegetation types. Results showed that the spatio-temporal variability of the vegetation phenology of the meadow steppe, typical steppe and desert steppe could be reflected by the monthly thermal and hydrological factors but the progressive earlier SOS and later EOS of the highly degraded steppe desert might be accounted for by non-climate factors only, suggesting that the vegetation growing period in the highly degraded areas of the grassland could be extended possibly by human interventions.

Assessing the impacts of human activities and climate variations on grassland productivity by partial least squares structural equation modeling(PLS-SEM)

The cause-effect associations between geographical phenomena are an important focus in ecological research. Recent studies in structural equation modeling（SEM） demonstrated the potential for analyzing such associations. We applied the variance-based partial least squares SEM（PLS-SEM） and geographically-weighted regression（GWR） modeling to assess the human-climate impact on grassland productivity represented by above-ground biomass（AGB）. The human and climate factors and their interaction were taken to explain the AGB variance by a PLS-SEM developed for the grassland ecosystem in Inner Mongolia, China. Results indicated that 65.5% of the AGB variance could be explained by the human and climate factors and their interaction. The case study showed that the human and climate factors imposed a significant and negative impact on the AGB and that their interaction alleviated to some extent the threat from the intensified human-climate pressure. The alleviation may be attributable to vegetation adaptation to high human-climate stresses, to human adaptation to climate conditions or/and to recent vegetation restoration programs in the highly degraded areas. Furthermore, the AGB response to the human and climate factors modeled by GWR exhibited significant spatial variations. This study demonstrated that the combination of PLS-SEM and GWR model is feasible to investigate the cause-effect relation in socio-ecological systems.

A preliminary evaluation of throughfall sampling techniques in a mature coniferous forest

Rainfall, throughfall and stemflow were measured and canopy interception loss was derived for 14 rainfall events from June 22 to August 30, 2008 within a mature declining hybrid white spruce （Picea glauca （Moench） Voss x p engelmannii Parry ex Engelm.） - subalpine fir （Abies lasiocarpa （Hook.） Nutt.） - lodgepole pine （Pinus contorta vat. latifolia Dougl. ex Loud.） stand in south-central British Columbia, Can- ada. Stemflow was negligible during the study period, while, respectively throughfall and canopy interception loss accounted for approximately 59.4% and 40.6% of the 50.1 mm of cumulative rainfall. Throughfall variability was assessed with three approaches involving roving and stationary wedge-type gauges, and stationary trough gauges. Throughfall exhibited large spatial variability with the coefficient of variability of study period throughfall sampled using 16 stationary trough gauges being 30.3%, while it was 38.0% and 28.7% for 32 stationary and 32 roving wedge gauges, respectively. Our analysis suggests that a roving gauge method is better than a stationary approach since the errors associated with event mean throughfalls are summed quadratically and a greater portion of the canopy area is sampled. Trough gauges were more efficient than wedge gauges; however, this efficiency was less than expected given their much larger sampling areas, suggesting that spatial autocorrelation lengths of throughfall may be longer than the trough systems. The spatial distribution of throughfall showed a high degree of temporal persistence throughout the study suggesting the existence of stable ＂wet＂ and ＂dry＂ inputs to the floors of these coniferous forests.

中亚热带红壤不同粒级有机质的化学特征及其对有机培肥的响应

为了解红壤区不同粒级土壤有机质的化学特征及其对有机培肥的响应,以湖南省祁阳县旱地红壤为研究对象,进行秸秆还田和施加有机肥的实验.采用湿筛法得到粗颗粒(>250μm)、细颗粒(53~250μm)和矿质结合组分(<53μm)共3种土壤粒级组分,利用元素分析仪和热裂解-气相色谱/质谱(Py-GC/MS)技术分别进行碳、氮含量和土壤化合物化学组成的测定和分析.结果表明:①27 a的有机培肥处理大幅增加了土壤中有机碳的含量,同秸秆还田相比,施加有机肥的增碳效果更显著.②全土中,施加有机肥使有机碳与总氮的含量分别显著提高了35.1%和32.0%,而未显著影响土壤的C/N(P>0.05).③粗颗粒中含有较多的芳香烃和木质素(主要指示植物来源);细颗粒中含有较多的脂肪族化合物;矿质结合组分中含有较多的酚类化合物和含氮化合物,表明它们具有较高的化学亲和力.同粒级组分相比,有机培肥对土壤有机质化学组成的影响较小,主要体现在对木质素和氨基化合物的影响上.综上,粒级组分对土壤的碳、氮含量与有机质的化学组成起主要调控作用,有机培肥方式对其影响相对较小.

地下人行道路网络的规划与设计

通过介绍地下人行道网络设计中考虑设定目的和采取方式、人流组织方案 ,说明了地下人行道路网规划和设计特点。

Land Cover Dynamics in the Kirisia Forest Ecosystem, Samburu County, Kenya

The study characterized the status and trend of land cover transformation in Kirisia forest ecosystem between 1973 and 2015 using remote sensing and GIS. The dominant land cover types consisted of indigenous forest followed by shrub land and bush land. The findings showed a major increase in the built environment by 55.4% and an overall reduction in forest cover by 21.3%. Up to 83.9 km2 of the original indigenous forest was lost between 1973 and 1986 due to severe fires. Thereafter, 23.7 km2 of the remaining indigenous forest was lost between 1986 and 2000 mainly through charcoal burning, illegal timber logging and livestock forage harvesting. A slight recovery occurred between 2000 and 2015 with a 5% increase in indigenous forest cover mostly through natural succession by shrub land and bush land in the burnt forest areas especially following the 1998 El Nino period. The land cover change in the forest ecosystem was not exceptional in Kenya but mirrors similar changes that have been documented in other valued dry land watershed ecosystems in the country including the national water towers. The continued loss of forest cover is likely to affect the water recharge capacity in the watershed thereby creating severe water scarcity for the people in Mararal town as well as nearly 142,954 other individuals in the Kirisia region. Appropriate interventions are therefore needed to mitigate the negative land cover change in Kirisia forest and restore its hydrological functions and water recharge capacity.

Developments of Rill Networks: An Experimental Plot Scale Study

Enumerating the relative proportions of soil losses due to rill erosion processes during monsoon and post-monsoon season is a significant factor in predicting total soil losses and sediment transport and deposition. Present study evaluated the rill network with simulated experiment of treatments on varying slope and rainfall intensity to find out the rill erosion processes and sediment discharge in relation to slope and rainfall intensity. Results showed a significant relationship between the rainfall intensity and sediment yield (r = 0.75). Our results illustrated that due to increase in rainfall intensity represent the development of efficient rill network while, no rill was found with a slope of 20° and a rainfall intensity of 60 mm·h-1. The highest rill length was observed in plot E with 20° slope and 120 mm·h-1 rainfall intensity at 360 minutes. Positive and strong correlation (R2 = 0.734, P 0.001) was observed between the cumulative rainfall intensity and sediment discharge. A longitudinal profile was delineated and showed that the depth and numbers of depressions amplified with time and were more prominent for escalating rainfall intensity for its steeper slopes. Information derived from the study could be applied to estimate longer-term erosion stirring over larger areas possessing parallel landforms.

Water Service Provision in Owerri City, Nigeria

The study investigates water service provision in Owerri-a Nigerian city. For the study both primary and secondary data were obtained and analysed. Secondary data were obtained from Imo State Water Corporation (ISWC) and the Works Department of Owerri Municipal Council. While, primary data were obtained from all the 17 wards that constitute Owerri city, i.e. the municipal area. Key informants were identified and interviewed using a structured interview schedule. The analysis of variance employed showed that there are significant differences in the water service provision pattern in the seventeen wards in Owerri city. The study found that though most residents of Owerri city rely heavily on commercial borehole owners and water tanker drivers/water peddlers for their daily supplies, the government through its SWA is in control, and there is an absence of a popularly acceptable regulatory framework/water policy. It recommends that Water decree 101 from 1993 (water legislation) be reviewed to address growing challenges. In order to enhance regular water supply at less cost, the study recommends that government should collaborate with the private sector and other community based organizations in a tripartite partnership. A new regulatory framework that will carry out government ownership and control of water resources and participatory aspects of water management should be produced by ISWC.

The Dynamics of Domestic Water Vending in Enugu North L.G.A of Enugu State, Nigeria

The present investigation provides a case study of water vending in Enugu North Local Government Area, Enugu State of South Eastern Nigeria. Questionnaire copies were randomly distributed in the study area to 200 households. Data obtained from the field were analyzed using descriptive statistics and chi-square test. The analysis revealed that almost all the residents of Enugu North L.G.A. obtain their water from independent water vending systems which are operated by the private sector. Tanker truck, distributing and small retail water vendors all operate in the study area. There are an estimated number of 250 tanker truck drivers serving Enugu North L.G.A. Approximately 35 tanker trucks serve Hill- top/Udi siding ward, while there are a total of 52 retail vendors in Onuasata ward. Majority of the respondents are low income earners who spend within the ranges of NGN500 ($3.33) and NGN1500 ($10) a month on water on the average. 50.0 percent of these respondents opined that vended water was expensive. Of the respondents, 49.4 percent consumed 91 - 100 litres per capita per day, which is less than the 120 litres per capita per day recommended by the Federal Re- public of Nigeria’s National water supply and sanitation policy document of 2000. This deficit can be attributed to the cost of vended water. From the chi-square test, there is significant difference in the unit cost of water sold by vendors in the various wards in Enugu North L.G.A. In the absence of regular water provision through pipe-connections from the public utility, water vending should be supported but regulated. Meeting the water and sanitation target and optimizing water resources for the Millennium Development Goals (MDGs) by 2015 will require a dramatic scaling up of joint efforts by the state government and the people in ensuring that vendors provide safe water at a low cost.

Assessment of Factors Affecting Ephemeral Gully Development in Badland Topography: A Case Study at Garbheta Badland (Pashchim Medinipur,

Gully erosion in the Paschim Medinipur district of West Bengal, Indiahas been an issue of anxiety, formed by the amputation of soil from narrow channels through the accretion of surface runoff. Here, we attempted to investigate the erosion variability of gully in a micro catchment area, and also scrutinized the gully cross-sectional areas as distinct components of gully volumes. Twelve gullies were randomly selected in different slopes. To determine the geometric growth of the gully dimensions and soil loss, the initial length of gully, the width of the gully and depth of respective gullies was monitored in different seasons. Univariate analysis was conducted to measure the association between gully head retreat and vegetation coverage, slope, rainfall volume and runoff contributing area. We found strong and significant relation between the slope of gully head and linear retreat in the pre monsoon (p 0.008) and post monsoon (p 0.024) season respectively. Conversely, rainfall volume and gully head retreat showed a strong relationship in the pre monsoon (r = 0.80), monsoon (r = 0.66) and post-monsoon period (r = 0.94);while meager relationship was observed with rainfall intensity (r = 0.06). Results also illustrated that the overall retreat of gully head had very strong and positive relationship with the runoff contributing area (r = 0.89, p 0.001), and maximum gully erosion was observed in the monsoon period (55.67%). These results indicate that slope, rainfall and runoff contributing area have a strong positive influence on gully erosion in Paschim Medinipur district, since the initiation of the gully.

The Impact of Deforestation in Anambra State： The Ekwusigo Example

It is a fact that demographic and socio-economic developments are exploitatively exerting severe pressure on forest resources in Nigeria. Not only has the economy of the people been severely affected but also the environment has witnessed accelerated soil erosion, especially in Eastern Nigeria. Accordingly, this study set out to explore the environmental and socio-economic impacts of deforestation using an empirical case. Two forested and two deforested sites in Ekwusigo L.G.A of Anambra State were closely studied with respect to deforestation indices. From the data generated, Student＇s t-test was used to attempt a statistical comparison of the forested and deforested sites. The findings indicate that forest cover depletion affected both the canopy openness and the number of non-timber forest products in the area, Finally, the paper stressed the need to maintain a sustainable plant cover while economically harnessing forest resources.

Assessment of School Infrastructure at Primary and Upper Primary Level: A Geospatial Analysis

With the introduction of powerful and high-speed personal computers, proficient techniques for infrastructure development and management have advanced, of which Geoinformatics technology is of great significance. An attempt has been made for broad mapping and analysis of existing infrastructures in the context of planning scheme in Paschim Medinipur district, and to delineate the development zones of educational infrastructure facilities. The thematic layers considered in this study are infrastructure accessibility, type and condition of classroom and number of classroom allocated for the educational system at primary and upper primary level. Moran’s I statistics was used to estimate the spatial distribution of elementary infrastructure across the district. All these themes and their individual features were then assigned weights according to their relative importance in educational development and corresponding normalized weights were obtained based on the Saaty’s analytical hierarchy process. The thematic layers were finally integrated in GIS software based on multi-criteria approach to yield educational development infrastructure index. Moran’s I statistics shows girl’s toilet, electric and boundary wall facility within the district are clustered in pattern at primary level. At the upper primary level, only electric and computer facilities shows the clustered distribution across the district. However, four different zones have been delineated, namely ‘very good’, ‘good’, ‘moderate’ and ‘poor’. The block covered by very good elementary educational infrastructure facility is Daspur –I and Dantan –II at primary level and Keshiary block at upper primary level in Paschim Medinipur district. Finally, it is concluded that the Geoinformatics technology is very efficient and useful for the identification of infrastructure development.

Quantitative Review of Ecosystem Services and Disservices Studies in the Tropics

The tropics host about 80% of the planet’s terrestrial species and over 95% of its corals. A well-known tropical forest ecosystem to provide significant global regulating services has declined at a rate of 5.5 M ha per year from 1990-2015, while another region noted an increase per year. There is evidence that tropical region ecosystem services and disservices are the least studied in the world. This study quantified peer-review papers in the tropics, then explored the neglected ecosystem type, service category, assessment mode, applied techniques and choice dependence between ecosystem type, service category, assessment mode and applied techniques. The Google Scholar and Web of Science database were used to collect all ES & ED studies available online from 1960 to December 2017. This review covered 102 countries with 578 articles. The study showed dramatic articles increase in the last three years as more than 50% of articles were published after the year of 2014. The top countries in high articles were Mexico (n = 53), India (n = 43), and Brazil (n = 35). The ES & ED assessment tools/techniques are barely applied in tropics as only social based techniques such as interviews and questionnaire take over 45%, while biophysical tools like remote sensing and GIS appeared only in 20%, InVEST only in 3% while the rest tools are less than 1% even none such as ARIES model. Urban and marine ecosystem types, disservices category and trade-off assessment mode were the least studied. The review concluded that policy analysis ES & ED studies do not reflect the trade-offs and synergy analysis between different services which hinder the development of pragmatic policy and decisions toward ES sustainable management in the tropics. The rampant urbanization in the tropics is subjected to destroy existing ES. Thus, this review highly suggested a high concern of urbanization ecosystem. This study also calls for great academic research to give attention to the tropical rainforest region as most African countries to host such forest have not even a single article on ES & ED.

Collaborating with Nature: The Pristine Habitats, in Ugep, Yakurr L.G.A., Nigeria

Pristine habitats serve as ecological resource for educational services and the conservation of biodiversity. The need to maintain a balance between nature and development is very important. When pristine habitats face changes due to anthropogenic activities, species erosion sets in and this will eventually lead to extinction. This subtle move in most cases is unnoticed until the effects are established. The pristine habitats in Ugep are faced with this challenge. The Ugep Urban Landuse Master Plan and Ugep Orthophoto map [1] have been used to identify the pristine habitats and further calculate the total landmass to be approximately 855.38 hectares. Ten (10) pristine habitats were identified within the residential blocks along the drainage corridors of Loblo, Isayi, Mma Oden, Kiwei, Ewiden and Oganghwen. The pristine block at Njelokoko-2 has the highest landmass, 201.01 hectares, representing 23.50 percent while Njelokoko-1 has the least landmass, 18.99 (2.22 percent). The spatial turnover of the species composition shows a trend of direct proportion with the landmass size and anthropogenic activities in the pristine habitats. Tree species such as Albizia zygia and Artocarpus communis rarely occurred together with other tree species. Among the bird species, it was observed that Dendropes goerae, Milvus migrans, Pica pica, and Streptopelia senegalensis roost, breed and feed in pristine habitats with emergent trees while Halocyno leucoephala, Halocyno malimbicus, Frasena clnernscens, Streptopelia semitorguata and Crimifer piscator are restricted to narrow corridors of pristine habitats along stream buffers. The nature that the pristine habitat portends and the species observed in such highly urbanized context as Ugep, are very important in conservation planning and meeting the urban challenges.

Predator-Proof Bomas as a Tool in Mitigating Human-Predator Conflict in Loitokitok Sub-County Amboseli Region of Kenya

Human-wildlife conflict (HWC) arises when wildlife shares the same physical space with humans. HWC, particularly livestock predation results in great negative impacts both to pastoralist and carnivores. Various approaches including compensation, livestock guarding, translocation of the problematic predator, and predator-proof bomas (PPB) have been used to mitigate such conflicts. We assessed PPB in mitigating human-predator conflict in Loitokitok sub-county by focusing on its effectiveness, most problematic predator, community’s perceptions, and comparing the PPB and traditional bomas characteristics. Data were obtained from 90 homesteads in Olgulului, Mbirikani and Kimana/Tikondo group ranches. Correlation and paired t-tests were used to analyze the data. Our findings suggest that the boma sizes correlated with the total number of livestock in the boma (r = 0.386, n = 90, p = 0.000) but not the number of people. Hyena and lion accounted for the highest loss of shoats and cattle, with hyena mostly killing shoats (37%) and lions preying largely on cattle (34%). The most problematic predator was as hyena (68%). We found positive relationships between the most problematic predator and total number of livestock (r = 0.319, n = 90, p = 0.002), and boma circumference (r = 0.295, n = 90, p = 0.005). Livestock predation was high in boma during the wet seasons (April, September, October and December). The erection of PPB reduced livestock predation by 91.11% (n = 45) and time spend guarding livestock at night. We recommend a continuous maintenance of the PPB as a long term solution to livestock loss at night and a close guarding of livestock during the day by adults to reduce day time predations.

Wildlife Population Change in Africa from the Eyes of the Public—The Case of Mara Enoonkishu Conservancy in Southern Kenya

The aims of the study were to: 1) determine the wildlife population trends in the Mara Enoonkishu Conservancy from the eyes and minds of the public, 2) assess the recent trends in wildlife populations based on actual scientific counts, and 3) compare the two patterns and establish whether they are similar or not. The solicitation of public views was based on household surveys using a standard questionnaire which was administered to 115 randomly selected respondents. The dominant wildlife species according to 39% of the respondents was the elephant followed by the zebra with 35%. 40% of the respondents indicated that the rhino population had declined followed by wild dogs (7%) and cheetah (6%). The actual counts showed that the herbivores with increasing populations included the rhino (r2 = 0.9992), impala (r2 = 0.9824), Thomson’s gazelle (r2 = 0.6965), Grant’s gazelle (r2 = 0.7052), elephant (r2 = 0.5798), and topi (r2 = 0.4426) while the increasing predators included the lion (r2 = 1.000), cheetah (r2 = 0.9093) and hyena (r2 = 0.8462). The actual wildlife counts appeared to tally with the public views only for the elephant and zebra. The actual counts contradicted the public views in terms of the rhino, lion and gazelles whose numbers were on the increase but the people did not appear to notice. Based on this, it was concluded that the public view on the wildlife population trend was not similar to the actual wildlife population status on the ground based on scientific monitoring.