Adjacent Land Use Research Articles

Effects of Land Use Types on Selected Soil Properties in Central Highlands of Ethiopia

Rapid land use changes have been observed in recent years in central Ethiopia. The shift from natural ecosystem to artificial ecosystem is the main direction of change. Therefore, this study was initiated to assess the effects of land use types on selected soil properties in Meja watershed, central highlands of Ethiopia. The randomized complete block design, including three adjacent land use types as treatments with three replications and two soil depths (0–15 and 15–30 cm), was applied in this study. There were significant differences in some soil properties among the three land use types. Lower soil pH and electric conductivity were observed in cultivated land soils than Eucalyptus woodlots soils. This has indicated the worsening soil conditions due to the shift from Eucalyptus woodlots to cultivated land. Less decomposition rate of the Eucalyptus leaves and debris collection for fuel could result in lowest soil organic carbon at the upper layer of Eucalyptus woodlot soils. However, the highest soil organic carbon at the lower layer was observed in Eucalyptus woodlot soils. The presence of highest soil potassium, cation exchange capacity, and exchangeable potassium in cultivated land soil was related to application of artificial fertilizers. Grassland soils have highest exchangeable sodium at the lower layer while highest soil carbon and sum cations at the upper layer, which can be related to the grass root biomass return and less surface runoff on grassland. There was the highest exchangeable sodium percentage on Eucalyptus woodlot soils at the upper layer; it can be due to the less surface nutrient movement and growth characteristics of the tree. The soils in cultivated land was shifted to more acidic and less electric conductivity.This shift can lead to soil quality deterioration that affects the productivity of the soils in the future.Nutrient leaching, application of artificial fertilizer, soil erosion, and continuous farming have affected the soil properties in cultivated land. The presence of highest exchangeable sodium percentage and lowest sum of cations at the upper layer of soil in Eucalyptus woodlot should be noted for management and decision makers. The previous negative speculations on Eucalyptus woodlots which can be related with the soil texture, soil moisture, bulk density, total nitrogen, exchangeable magnesium, calcium, and available sulfur should be avoided because there were no significant differences observed among the three land use types in the study area. The study recommends further studies on the effects of Eucalyptus on soil properties by comparing among different ages and species of Eucalyptus. Finally, planting of Eucalyptus on central highlands of Ethiopia should be supported by land use management decision.

English

In Ethiopia, where sugarcane has been cultivated for over 20 years, changes in soil physicochemical properties are expected to occur albeit information on the extent of change is scanty. A study was conducted in 2015 at Finchaa Sugar Estate with the objective of assessing the status of selected soil properties under long term mechanized sugarcane cultivation. Disturbed composite and undisturbed soil samples from 0-30 and 30-60 cm layers of selected Luvisols and Vertisols at Finchaa were collected for laboratory analysis of selected soil properties. The result of the study indicated that clay content of the land under sugarcane was higher than that of the adjacent uncultivated land use types. The bulk density values for a clay texture for most of the studied soils were higher than the critical values recommended for successful sugarcane production. The pH of the two land uses also ranged from 5.35 to 6.63. Organic carbon (0.95 to 1.32%), total nitrogen (< 0.12%), and available P (2.51-8.63 mg kg-1) were also in the range of those not adequate for sugarcane cultivation. Overall, the measured soil properties indicated that the management practices the estate has been implementing were not adequate to sustain sugarcane production on a profitable basis and, thus, require revisiting the practices. To maintain sustainability of sugarcane production in the estate; soil management practices that can increase soil organic carbon, pH, total nitrogen and soil available P should be employed. Key words: Sugarcane, soil physical property, soil chemical property.

INFLUENCE OF LAND USE SYSTEMS ON CARBON STOCK AND STRUCTURAL STABILITY OF A TROPICAL ALFISOL

The study was conducted to investigate the influence of four adjacent land use systems (Arable [A], Pasture [PL], Fallow [FL] and orchard [OL]) on carbon stock and structural stability of a tropical Alfisol in Sudan Savannan agro-ecological zone of Nigeria. The result reveals that carbon stock was statistically higher (P = 0.03) in OL and FL than the other two land use systems. Carbon stock in the soil increased by 5.67t ha-1 in OL relative to FL for over 10 years. But in contrary, a decline in carbon stock of 6.4 t ha-1 and 4.9 t ha-1 was observed relative to FL in AL and PL, respectively. This indicates soil carbon stock in the study area lost rapidly under continuous arable cropping than any other land use systems. Correlation analysis showed that soil carbon stock in the study area was significantly explained by clay (r = 0.71**), silt (r = 0.54*) and sand (r = -0.70**) contents. The structural stability index (SI) did not significantly vary (P = 0.195) among the land use systems were all values fell below less than 5% that indicates structurally degraded condition of the soil due to generally small organic carbon content. The structural stability index was significantly related to pH in KCl2, available phosphorus and carbon stock with correlation coefficients (r) of 0.45*, 0.62** and 0.72**, respectively. Therefore, there is a need to adopt proven management practices that enhance and maintain organic carbon content especially in the AL in order to improve productivity and structural stability of the soil vis-à-vis environmental resilience.

Impact of anthropogenic transformations on the vegetation of selected abiotic types of rivers in two ecoregions (Southern Poland)

The quality of water in rivers is declining worldwide due to anthropogenic activities. This phenomenon may be exacerbated by climate change and population growth. We hypothesised that both physical and chemical parameters of water, which reflect the differences in the underlying geology and anthropogenic transformations, are the most important characteristics to explain the distribution of macrophytes in rivers. In the present study, we analysed the effect of anthropogenic transformation on the structure of macrophytes in eight rivers within the river basins of the Vistula and Oder Rivers (Southern Poland). A canonical correspondence analysis showed that conductivity, altitude, natural features of rivers and adjacent land use, which are indicated by the values of the Hydromorphological Diversity Index (WRH), and medium sand were the most important factors that affected the distribution of macrophytes. The eurytopic species, including invasive alien species, were negatively correlated with the WRH index and positively correlated with high conductivity. An increase in the conductivity led to a loss of vegetation diversity and caused the replacement of freshwater species with brackish or salt-resistant species. Salinity of 2.96–5.16 PSU decreased the number of macrophyte taxa by over 30% in the rivers as compared to salinity of 0.45–0.64 PSU. Because very few studies have investigated the effect of salinity on macrophytes, further research is needed to explain this phenomenon. We therefore suggest extensive use of hydromorphological indices in studies on the distribution of macrophytes in rivers.

Habitat Characteristics Affecting Wading Bird Use of Geographically Isolated Wetlands in the U.S. Southeastern Coastal Plain

Geographically isolated wetlands (GIWs) have been increasingly recognized for their importance in providing ecosystem services, including support of regional biodiversity. These wetlands serve as valuable foraging and breeding habitat for wetland-dependent species, including wading birds. In certain regions of the U.S. Southeastern Coastal Plain approximately two-thirds of GIWs are impacted by adjacent human land use. We quantified wading bird density in agricultural and natural GIWs to determine the factors influencing their use of these habitats. Using monthly transect surveys, we found that wetland-specific variables, including prey abundance and size, wetland surface area, and dry-down rate, were better predictors of wading bird density than landscape level variables such as wetland density and distance to breeding colony. Bird density was highest in agricultural wetlands early in the hydroperiod, but as GIWs dried down, density dropped in agricultural wetlands and rose in natural wetlands. Collectively, these results suggest that wading birds in the Coastal Plain rely on a matrix of both agricultural and natural wetlands, and their use of wetlands varies temporally, peaking in late spring, to maximize prey availability. The seasonal process of receding water levels in GIWs and subsequent concentration of aquatic fauna provides important food resources for nesting wading birds.

Occurrence, source estimation and risk assessment of pharmaceuticals in the Chaobai River characterized by adjacent land use

This study investigated the occurrence of 27 pharmaceuticals with diverse physicochemical properties in a year-long monitoring campaign in the Chaobai River, China. The correlation between the distribution of pharmaceuticals in the river and the adjacent sources was elucidated. The results indicate that the agriculture area was the most polluted area with a median summed pharmaceutical concentration of 225.3 ng L−1, followed by the urban area and the mountain area with the corresponding values of 136.9 and 29.9 ng L−1, respectively. In terms of individual compounds, 22 out of 27 compounds were detected with concentrations ranging from <1 to 1972 ng L−1. Caffeine, carbamazepine, azithromycin, bezafibrate, metoprolol, sulfadiazine, sulfamethoxazole, clarithromycin, erythromycin, roxithromycin, and trimethoprim were pharmaceuticals with relatively high levels, with median concentrations ranging from 3.3 to 25.6 ng L−1 and detection frequencies ranging from 40% to 97%. Higher concentrations were mainly observed during cold seasons, with mean concentrations 1 to 52 times as high as those during warm seasons. Spatial analysis reveals that the pharmaceutical concentrations in different areas were impacted by different sources. A wastewater treatment plant was an important source in the urban area, while the agriculture area was impacted by various treated and untreated wastewater sources. The species sensitivity distribution model and risk quotient (RQ) method were combined in the ecological risk assessment. The results indicate that the multi-substance potentially affected fraction (msPAF) values of the sampling sites were below 0.04%, whereas nearly half of RQ values were higher than 1. Caffeine was proposed as a priority compound due to its high contribution rate (i.e., 79%) to the cumulative msPAF value, which implies that increased control and management of untreated wastewater sources along the Chaobai River is necessary.

Recovery of thermophilic Campylobacter by three sampling methods from river sites in Northeast Georgia, USA, and their antimicrobial resistance genes.

Sixteen sites in the watershed of the South Fork of the Broad River (SFBR) in Northeastern Georgia, USA, were sampled in two seasons to detect Campylobacter. Sites were classified as mostly influenced by forest, pasture, wastewater pollution control plants (WPC) or mixed use. Sampling was repeated in the late spring and late fall for 2years for a total of 126 samples. Free-catch water and sediment grab samples were taken at each site; Moore's swabs were placed for up to 3days at most sites. A total of 56 isolates of thermophilic Campylobacter were recovered. Thirteen samplings were positive by two or three methods, and 26 samplings were positive by only one method; once by Moore's swab only and 25 times by free-catch water only. Campylobacter was detected at 58% of cattle pasture sites, 30% of forested sites and 81% of WPC sites. Twenty-one of the isolates carried antimicrobial resistance genes, mostly blaOXA-61. Free-catch water samples were more efficient than Moore's swabs or sediment samples for recovery of Campylobacter, which was more likely to be detected in streams near cattle pastures and human communities than in forested land. SIGNIFICANCE AND IMPACT OF THE STUDY: The role of environmental water in transmitting Campylobacter was investigated, and methods for recovery of the organism were compared. The sequence types of recovered Campylobacter correlated with adjacent land use without regard to the method used to isolate the organisms. Sequence types and antimicrobial resistance genes associated with cattle were most prevalent near pastures. Even though types were recurrent at a given site, types appeared to be lost or replaced as the water flowed downstream.

Road Users’ Behavior at Marked Crosswalks on Channelized Right-Turn Lanes at Intersections in the State of Qatar

At non-signalized marked crosswalks, pedestrian priority is neither well-defined nor well acknowledged by drivers. This paper presents the findings of an investigation on both driver and pedestrian behavior at non-signalized marked crosswalks located on channelized right-turn lanes at intersections in the State of Qatar. Five crosswalks in Doha city were video recorded from discrete locations on a typical working day. The results from the data analysis of 1620 pedestrians’ behavior indicated that waiting behavior, gap acceptance, and crossing speed are complex phenomena and depend upon both pedestrians’ characteristics as well as their crossing characteristics. The drivers’ yielding behavior was mainly linked to pedestrians’ gender and adjacent land use. Low driver yielding rates indicated that significant improvements are required to enhance pedestrian safety. Among pedestrian attributes, gender had the most significant effect on crossing behavior followed by distractions, crossing in a group or alone, and dressing style. Findings of this research will be useful for planners when designing crosswalks at new intersections and during simulations of pedestrian and driver behavior at marked crosswalks on exclusive right-turn lanes. The results of this study will also be directly applicable to the Arabian Gulf countries as they exhibit similar conditions as the State of Qatar.

Mediation of area and edge effects in forest fragments by adjacent land use.

Habitat loss, fragmentation, and degradation have pervasive detrimental effects on tropical forest biodiversity, but the role of the surrounding land use (i.e., matrix) in determining the severity of these impacts remains poorly understood. We surveyed bird species across an interior-edge-matrix gradient to assess the effects of matrix type on biodiversity at 49 different sites with varying levels of landscape fragmentation in the Brazilian Atlantic Forest-a highly threatened biodiversity hotspot. Both area and edge effects were more pronounced in forest patches bordering pasture matrix, whereas patches bordering Eucalyptus plantation maintained compositionally similar bird communities between the edge and the interior and exhibited reduced effects of patch size. These results suggest the type of matrix in which forest fragments are situated can explain a substantial amount of the widely reported variability in biodiversity responses to forest loss and fragmentation.

RESEARCH AFFECT ECOLOGICAL-ECONOMIC FACTORS ON LAND USE OF AVIATION TRANSPORT

&#x0D; &#x0D; &#x0D; The article has been considered the influence of ecological and economic factors on ecologically safe, rational, economically efficient landing of aviation transport. The analysis of the harmful influence of aviation transport on the adjacent land use, as well as vital activity and health of people in the area of maximum, critical activity of the industry has been carried out. The methods of environmental management of the airport activity have been presented in order to prevent the occurrence and reduction of pollution of the environment by applying the Ecological Management System - the system of ecological management. Possible algorithm of ecological-economic estimation of design decisions in the context of interconnected operation of infrastructure of airline, aerodrome territory and adjacent land uses has been suggested.&#x0D; &#x0D; &#x0D;

Quantifying how landscape composition and configuration affect urban land surface temperatures using machine learning and neutral landscapes

The urban heat island effect is an important 21st century issue because it intersects with the complex challenges of urban population growth, global climate change, public health and increasing energy demand for cooling. While the effects of urban landscape composition on land surface temperature (LST) are well-studied, less attention has been paid to the spatial arrangement of land cover types especially in smaller, often more diverse cities. Landscape configuration is important because it offers the potential to provide refuge from excessive heat for both people and buildings.We present a novel approach to quantifying how both composition and configuration affect LST derived from Landsat imagery in Southampton, UK. First, we trained a machine-learning (generalized boosted regression) model to predict LST from landscape covariates that included the characteristics of the immediate pixel and its surroundings. The model achieved a correlation between predicted and measured LST of 0.956 on independent test data (n = 102,935) and included predictors for both the immediate and adjacent land use. In contrast to other studies, we found adjacency effects to be stronger than immediate effects at 30 m resolution. Next, we used a landscape generation tool (Landscape Generator) to alter landscape configuration by varying natural and built patch sizes and arrangements while holding composition constant. The generated neutral landscapes were then fed into the machine learning model to predict patterns of LST.When we manipulated landscape configuration, the average city temperature remained the same but the local minima varied by 0.9 °C and the maxima by 4.2 °C. The effects on LST and heat island metrics correlated with landscape fragmentation indices. Moreover, the surface temperature of buildings could be reduced by up to 2.1 °C through landscape manipulation.We found that the optimum mix of land use types is neither at the land-sharing nor land-sparing extremes, but a balance between the two. In our city, maximum cooling was achieved when ~60% of land was left natural and distributed in 7–8 patches km−2 although this could be location dependent and further work is needed. Opportunities for urban cooling should be required in the planning process and must consider both composition and configuration at the landscape scale if cities are to build capacity for a growing population and climate change.

Strength of forest edge effects on litter‐dwelling macro‐arthropods across Europe is influenced by forest age and edge properties

AbstractAimForests are highly fragmented across Western Europe, making forest edges important features in many agricultural landscapes. Forest edges are subject to strong abiotic gradients altering the forest environment and resulting in strong biotic gradients. This has the potential to change the forest's capacity to provide multiple ecosystem services such as nutrient cycling, carbon sequestration and natural pest control. Soil organisms play a key role in this perspective; however, these taxa are rarely considered in forest edge research.LocationA latitudinal gradient of 2,000 km across Western Europe.MethodsWe sampled six dominant taxa of litter‐dwelling macro‐arthropods (carabid beetles, spiders, harvestmen, centipedes, millipedes and woodlice) in forest edges and interiors of 192 forest fragments in 12 agricultural landscapes. We related their abundance and community composition to distance from the edge and the interaction with forest age, edge orientation and edge contrast (contrast between land use types at either side of the edge).ResultsThree out of six macro‐arthropod taxa have higher activity‐density in forest edges compared to forest interiors. The abundance patterns along forest edge‐to‐interior gradients interacted with forest age. Forest age and edge orientation also influenced within‐fragment compositional variation along the forest edge‐to‐interior gradient. Edge contrast influenced abundance gradients of generalist predators. In general, older forest fragments, south‐oriented edges and edges along structurally more continuous land use (lower contrast between forest and adjacent land use) resulted in stronger edge‐to‐interior gradients while recent forests, north‐oriented edges and sharp land use edges induced similarity between forest edge and interior along the forest edge‐to‐interior gradients in terms of species activity‐density and composition.Main conclusionsEdge effects on litter‐dwelling macro‐arthropods are anticipated to feedback on important ecosystem services such as nutrient cycling, carbon sequestration and natural pest control from small forest fragments.

Trait-based evaluation of plant assemblages in traditional farm ponds in Korea: Ecological and management implications

The Korean traditional farm pond called dumbeong is an important rural landscape element that supports local biodiversity and is useful in irrigating agricultural fields during dry periods. This study assesses how plant communities in dumbeongs respond to adjacent land use, water depth, open-water surface, and nutrient levels and irrigation usage. Plant functional and species groups, based on trait and species data respectively from 20 dumbeongs in Seocheon-gun, South Korea, were classified by hierarchical analysis and non-metric multidimensional scaling. Relationships between the plant community composition and explanatory variables at both the species and functional group levels were tested through redundancy analysis. The results showed that irrigation usage prevented nutrient accumulation and water depth reduction of the ponds, and we found water depth was the only significant factor that determined plant composition at both species and functional group levels. The plant functional groups were more useful than plant species in predicting plant composition in dumbeongs, owing to their collective response to water depth and open-water surface. Our results demonstrate that management practices of dumbeong, such as periodic drainage, sediment removal and control of dominant plant species, alter its plant communities and thus need to be considered for biodiversity conservation in agricultural landscapes.&#x0D;

Woody species diversity, population structure, and regeneration status in the Gra-Kahsu natural vegetation, southern Tigray of Ethiopia

The study was conducted at Gra-Kahsu protected natural vegetation (PNV) and communal grazing land (CGL), in order to evaluate the conservation impact level. The diversity of plant species, population structure of woody species, and regeneration status were analysed from 62 quadrats, each with 20 m × 20 m for trees and 5 m × 5 m for shrubs, using systematic sampling methods. A total of 64 vascular plant species belonging to 52 genera and 37 families from PNV and 43 plant species belonging to 34 genera and 25 families from CGL was identified. Shannon diversity index values of PNV and CGL were 2.29 and 1.84, respectively. The mean basal area of PNV and CGL were 8.29 and 5.32 m2/ha, respectively. Three community types from PNV and two from CGL were identified. The population structure of woody species based on diameter and height class distribution showed reflected reversed J-shape for PNV however, bell-shaped, and interrupted inverted J-shape for CGL. The regeneration status of PNV and CGL were considered as good (sapling > seedling > matures) and fair (mature > sapling > seedling), respectively. Therefore, the floristic analysis of these two adjacent land use systems located in similar landscape showed distinctive variation in floristic composition, diversity, and regeneration status, which could be taken as the best practice of restoration and rehabilitation programs like, area exclosure.

A multi-criterion approach for prioritizing areas in urban ecosystems for active restoration following invasive plant control.

Resources for biodiversity conservation and invasive plant management are limited, and restoring invaded vegetation is labour-intensive and expensive. Managers must prioritize their actions to achieve their goals efficiently and effectively. They must distinguish between areas that require only the removal of invasive alien plants ("passive restoration") from those that require additional restoration measures ("active restoration"). This study used a multi-criterion approach (Analytical Hierarchical Process) to develop a framework for identifying areas that require active restoration, and then to prioritize these areas for active restoration. The South African city of Cape Town is used as a test case to illustrate the utility of the framework. Framework criteria selected in determining the need for active restoration included: dominant alien species invading the area, density of invasion, duration of invasion, indigenous vegetation cover, adjacent land use, level of disturbance, size of the area, aspect, soil texture, soil depth and erodibility, slope and vegetation type. In deciding which areas to prioritize for active restoration, factors such as vegetation conservation status, selection in a regional conservation plan and connectivity function were assessed. Importance in ecosystem functioning (by providing a diversity of habitats and soil conservation) and the delivery of ecosystem service benefits were also considered. The resulting framework provides an objective tool for prioritizing sites for active restoration.

Lost forever? Ecosystem functional changes occurring after agricultural abandonment and forest recovery in the semiarid Chaco forests

Semiarid forests are worldwide threatened by land use changes, particularly agriculture. However, in some cases, due to particular economic or social processes, agriculture ends and forests may or may not recover to their original state. Using different databases and satellite images integrated into a geographical information system, we located in the central region of the semiarid Chaco forests of Argentina adjacent land use patches of secondary forest (SF), remnant forest (RF) and crops (CP). Using a chronosequence approach, we evaluated changes in the fraction of the photosynthetic active radiation absorbed by the vegetation (FAPAR) between SF and RF and CP, using the enhanced vegetation index (EVI). We evaluated both intra and inter-annual changes in EVI mean (EVImean), EVI maximum (EVImax), EVI minimum (EVImin), and EVI relative range (EVIrr) as descriptors of FAPAR dynamics and analyzed their changes through time (2000 to 2010) and their relation to rainfall. Secondary forests showed higher seasonality and higher EVImean values than RF, but differences disappeared as time since agricultural abandonment increased, suggesting that SF recover their functioning (when compared to RF) after 10 to 15 years. Our results suggest that Chaco's SF have intermediate seasonal patterns in-between RF and CP, as expected by successional theory, and that FAPAR interception by RF appears to be dependent on previous year's precipitation. We found that, although all land uses showed similar precipitation use efficiency (PUE), SF and cropland's productivity were less stable across the years and showed faster increases or decreases compared to RF, depending on precipitation (higher precipitation marginal response- PMR). Our results suggest that at least some aspects of ecosystem functioning can be restored after agricultural abandonment. Future research that combines floristic and structural changes is necessary to fully understand secondary forests regrowth process after agricultural abandonment in the Chaco region.

Temporal variation of soil organic carbon and total nitrogen stock and concentration along land use, species and elevation gradient of chilimo dry afromonate forest and adjacent land uses, ethiopia

Forests play a vital role in the natural global carbon cycle by capturing carbon from the atmosphere through photosynthesis and converting it into forest biomass. Forests sequester and stores more carbon than any terrestrial ecosystem and act as sources as well as sinks of CO2. However, the increasing rate of deforestation and the impact of changes in land use require a critical and updated look at what is happening in the tropics. This work emphasized the temporal variation of bulk density, carbon (C) and nitrogen (N) stock and concentration in four land-use categories: natural forest, tree plantations, crop-land and degraded soil along elevation gradient and soil depth. The study was conducted in the Central Highlands of Ethiopia, where deforestation and human pressure on native forests are exacerbated and erosion has caused extensive soil loss. We hypothesized that, there is temporal variation of C and N concentrations and stocks in native forest along elevation gradient, land use type, species and soil depth. Carbon and N concentrations and stock and bulk densities in mineral soil were analysed as repeated measures in an irregular vertical space ranging from 0–10 cm, 10–30 cm, 30–50 cm and 50–100 cm, using a linear mixed model approach in two-time scale period 2012 - 2017. Double observations in 2012 and 2017, were made from the forest floor were analysed by a general linear mixed model. There is significant variation in organic carbon and nitrogen stock along elevation gradient for forest floor. Results also indicated that soil depth is more important factor than elevation gradient in native forests, though C and N concentrations and stocks diminished near human settlements. Native forest stored on average more nitrogen than bare soil, cropland and plantations, respectively. Conversion of crop and degraded land into plantations ameliorated soil degradation conditions, but species selection did not affect carbon and nitrogen stocks. Thus, appropriate forest management options should be applied in order to increase productivity and carbon sink of Chilimo dryafromontane forest and adjacent land use. Temporal monitoring and reporting of carbon stock and concentration is also important to understand the role of Chilimo dryafromonate forest in climate change mitigation and adaptation agendas.

Do grazers respond to or control food quality? Cross-scale analysis of algivorous fish in littoral Lake Tanganyika

Food quality determines the growth rate of primary consumers and ecosystem trophic efficiencies, but it is not clear whether variation in primary consumer densities control, or is controlled by, variation in food quality. We quantified variation in the density and condition of an abundant algae-eating cichlid, Tropheus brichardi, with respect to the quality and productivity of algal biofilms within and across rocky coastal sites in Lake Tanganyika, East Africa. Adjacent land use and sediment deposition in the littoral zone varied widely among sites. Tropheus brichardi maximized both caloric and phosphorus intake at the local scale by aggregating in shallow habitats: algivore density decreased with depth, tracking attached algae productivity (rETRMAX) remarkably well (r2 = 0.84, P = 0.00033). In contrast, algivore density was unrelated to among-site variation in algal productivity. Rather, there was significant increase in algal quality (r2 = 0.44, P = 0.011) and decrease in algal biomass (r2 = 0.53, P = 0.0068) with T. brichardi density across sites, consistent with strong top-down control of primary producers. The amount of inorganic sediment on rock surfaces was the strongest predictor of among-site variation in algivore density (r2 = 0.69, P = 0.00096), and algivore gut length increased with sedimentation (r2 = 0.36, P = 0.034). These patterns indicate extrinsic and top-down forcing of algal food quality and quantity across coastal landscapes, combined with adaptive habitat selection by fish at the local scale. Factors that degrade food quality by decreasing algal nutrient content or diluting the resource with indigestible material are likely to depress grazer densities, potentially dampening top-down control in high-light, low-nutrient aquatic ecosystems.

Carbon Storage and Nutrient Stocks Distribution of Three Adjacent Land Use Patterns in Lake Danao National Park, Ormoc, Leyte, Philippines

The country experienced drastic decrease of forest cover due to land use conversion, cutting of trees and doing agriculture to support food security. Secondary forests are an important component of land cover in the tropics, and when transformed or converted into another land-use, it is believed to have negative effects on some soil properties and forest ecosystem in general. A paired-area/space-for-time substitution approach was conducted to determine the changes in carbon storage: soil organic carbon (SOC) and total above ground biomass (TAGB), soil nutrient stocks and fertility status due to land use change. The study was conducted in Lake Danao National Park (LDNP), Ormoc City, Leyte, Philippines. Adjacent to the secondary forest (&lt;1 km away), grassland and forest plantation land uses were chosen and sampled for possible changes on SOC, TAGB and nutrient stocks due to land use change. Results showed that conversion of forest to grassland and forest plantation decreased the organic carbon, exchangeable aluminum, exchangeable acidity, effective cation exchange capacity, TAGB while pH in H2O; exchangeable magnesium and potential cation exchange capacity increased when the forest was converted to grassland and forest plantation. Additionally, available P, base saturation, Ca, K, and Na increased while total N, and SOC stocks decreased when the forest was converted to grassland and forest plantation. This study indicates that conversion of forest to grassland and forest plantation greatly affected the SOC stocks, TAGB, soils nutrient stocks and fertility status. It also revealed that changes in soil properties largely depended upon the land use.

Land use type, forest cover and forest edges modulate avian cross‐habitat spillover

AbstractNatural habitats adjacent to agricultural areas are often considered sources of species that provide beneficial regulating ecosystem services through cross‐habitat spillover. Both inter‐habitat matrix and landscape configuration can influence spillover by controlling organismal ability to disperse through landscapes, and affecting the provision of additional or supplementary resources that impact organism survival.To understand how landscape structure in terms of matrix land use type, forest cover and edge density might facilitate avian cross‐habitat spillover, we sampled avian communities in forest patches and adjacent land use types (coffee plantations or cattle pastures) using a well‐replicated study design across 92 sampling sites across a landscape‐context forest cover gradient (6%–60%).Land use type was a key factor influencing avian cross‐habitat spillover, facilitating species movement into coffee plantations and acting as a barrier to spillover into cattle pastures. We found that 24% of the forest‐dependent species pool was capable of spillover into coffee plantations, while spillover was nearly non‐existent in cattle pastures.Forest cover was also the main driver of spillover into coffee plantations. There was a positive relationship between forest cover and spillover, potentially due to processes related with (1) a higher density of organism in‐patches, (2) decreased isolation among patches facilitating species movement and (3) higher landscape supplementation processes.Finally, we found edge density had an additive effect with forest cover on spillover. Spillover was higher in high‐forested landscapes with many forest‐matrix edges, possibly due to increased structural connectivity for species able to move through edges, and to improved access for forest‐dwelling species to different resource types (complementation processes).Synthesis and applications. We demonstrate that land use type is a key factor facilitating species spillover into agricultural matrices and that the influence of land use type on spillover is further modulated by a combination of native habitat amount and edge density. These results should be considered in efforts to design or manage sustainable agricultural landscapes in order to enhance both bird persistence and the provision of bird‐mediated ecosystem services.