International Journal of Ecology
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Open Access journal
ISSN (Print) 1687-9708 - ISSN (Online) 1687-9716
Published by Hindawi [334 journals]
- Patterns of Allocation CSR Plant Functional Types in Northern Europe
Abstract: Morphological and physiological parameters of 76 vascular plant species typical for Northern Europe were analyzed using Grime’s classification. species (competitors) have high levels of canopy height, leaf dry weight, and maximal lateral spread. species (ruderal) have low leaf dry weight, longer flowering period, high rate of photosynthetic capacity and respiration, and high nitrogen content in the leaves. Stress-tolerant () species prevailing in habitats with limited resources are small and have low rate of photosynthetic activity and respiration. Principal component analysis (PCA) ordination showed a clear separation of species of different plant functional types according to their morphological and physiological parameters. The first PCA axis showed close relationship with the rate of respiration and photosynthetic activity and allowed us to differentiate from species. The second PCA axis correlated with morphological parameters associated with the size of plants and allowed us to differentiate species from and species. Using PCA ordination, we developed a model that determines plant functional types in Northern Europe and analyzed plant functional types of several species that are not presented in Grime’s classification. The proposed model has higher accuracy (84%) compared to similar models designed for other climatic zones.
PubDate: Sun, 20 Nov 2016 07:03:25 +000
- Comparative Foraging Efficiency of Two Sympatric Jackals, Silver-Backed
Jackals (Canis mesomelas) and Golden Jackals (Canis aureus), in the
Ngorongoro Crater, Tanzania
Abstract: The foraging efficiency of two sympatric species of jackals, silver-backed jackals (Canis mesomelas) and golden jackals (Canis aureus), was studied in the Ngorongoro crater from July 2014 through May 2015. The focal animal observation method was used and individuals of both species were followed as they foraged from morning to evening. Observations of individuals of both jackal species were made from a vehicle using binoculars and a spotting scope. Three major parameters were used for determination of foraging efficiency: distance travelled while foraging, time spent foraging, and amount of food secured in foraging period. The Mann–Whitney test showed no significant difference () in distance travelled per unit time of foraging between the two species in the dry and wet seasons, respectively. Golden jackals secured a significantly higher amount of food than the silver-backed jackals in the wet season (Mann–Whitney test, , ). Hunting of prey larger than Thomson’s gazelle (Eudorcas thomsonii) fawns was not common. Both species mainly fed on smaller prey such as invertebrates and rodents and scavenged opportunistically. Efficient foraging is crucial for both jackal species especially during their breeding season when they are provisioning dependent pups.
PubDate: Sun, 13 Nov 2016 14:39:58 +000
- Differences in Functional Trait Distribution between Inselberg and
Adjacent Matrix Floras
Abstract: Inselbergs and the adjacent matrix represent extremes of different environmental conditions and should shed light on the changing allocation of plant resources across strong and abrupt resource gradients. Here I use collated life history trait data from 840 taxa found within typical insular inselberg and adjacent matrix floras from the New England Batholith region of eastern Australia. These species were sorted into guilds of specificity to the inselberg environment. Scored traits include life form, plant height, leaf area, fruit size, seed size, mono- or polycarpy, underground storage organs, regenerative/clonality, and flowering phenology. With reduced water and nutrient resources, typical of inselbergs, allocation of plant resources to vegetative reproduction and storage organs is a disadvantage. Plants restricted to inselbergs were shorter, usually polycarpic shrubs, with smaller leaves, fruits, and seeds. Flowering time was found to be earlier and reduced in length; diaspores often have dormancy and are dispersed locally in comparison to the matrix. The results show that with limited resources the creation of underground storage organs or vegetative reproduction becomes unviable on habitats characterised by shallow soil. Inselberg taxa of the study region are likely to be under greater threat than the matrix due to anthropogenic climate change.
PubDate: Tue, 25 Oct 2016 12:45:09 +000
- Notes on the Wild Tomistoma Populations in Western Sarawak, Malaysian
Abstract: Tomistoma schlegelii, the Freshwater Malayan Gharial or Tomistoma (local name: buaya jejulong), is secretive in nature; thus, very limited information is currently available on its wild population, especially in Sarawak. The objective of this study is to describe effort in assessing the Tomistoma wild populations in Ulu Sebuyau, Samarahan, and Serian, western Sarawak. Despite many challenges faced, this research has been successful at different levels. There was no Tomistoma seen during day surveys (2014-2015) in tributary of Samarahan River (Samarahan), Bunga-Baki River (Serian), and Kepayang River (Ulu Sebuyau). However, the research team came across two incidents of Tomistoma captured by the local people: (i) an adult male Tomistoma, captured in February 2015 in peat swamp area of Samarahan River tributary, and (ii) a hatchling, caught in Bunga-Baki River in March 2015. The sightings of Tomistoma in Kepayang River were reported by local people in February 2016; however, no individual was captured. The presence of hatchling in Bunga-Baki River indicates that a breeding population is most likely to occur in the area, and this gives hope for future conservation of Tomistoma in Sarawak. All sampling sites recorded almost similar water quality parameters and landscape of peat swamp areas, which previous studies claimed to be the potential Tomistoma habitats. The findings of this study should help relevant state agencies to step up efforts related to conservation of Tomistoma in Sarawak.
PubDate: Thu, 20 Oct 2016 12:12:02 +000
- Logging Activity Adversely Impacts Primate Diversity and Density in the
Kwabre Rainforest of Ghana
Abstract: Knowledge on the impacts of logging activity on inhabitant primate species in Kwabre Rainforest, Ghana, is vital for the development of a comprehensive conservation and management plan. With this background, primate density and diversity were recorded along line transects in logged and unlogged areas (strata) to assess the impact of logging activity on these parameters. Six distinct primate species were confirmed including Roloway monkey (Cercopithecus roloway, listed as endangered in the IUCN List of Threatened Species), white-naped mangabey (Cercocebus lunulatus, vulnerable), and Geoffroy’s black-and-white colobus (Colobus vellerosus, vulnerable). There was a significant difference (Mann-Whitney test: , ) in primate encounter rates between the logged and unlogged strata with higher species diversity in unlogged stratum () compared to the logged stratum (). Regression analysis indicated a significant effect (, ) of logging on primate encounter rates. Our results suggest that logging activity can alter composition of primate communities. One option to forestall further forest degradation and its adverse effects on primates would be to grant the Kwabre Rainforest protected area status under Ghanaian law and manage it under an integrated conservation plan that includes neighbouring Ankasa Conservation Area in Ghana and Tanoé Forest in Cote d’Ivoire.
PubDate: Mon, 29 Aug 2016 16:36:38 +000
- Comparing the Performance of Protected and Unprotected Areas in Conserving
Freshwater Fish Abundance and Biodiversity in Lake Tanganyika, Tanzania
Abstract: Marine protected areas have been shown to conserve aquatic resources including fish, but few studies have been conducted of protected areas in freshwater environments. This is particularly true of Lake Tanganyika, Tanzania. To better conserve the lake’s biodiversity, an understanding of the role played by protected areas in conserving fish abundance and diversity is needed. Sampling of fish and environmental parameters was performed within the Mahale Mountains National Park (MMNP) and nearby unprotected areas at depths between 5 m and 10 m. Twelve replicates of fish sampling were performed at each site using gillnets set perpendicularly to the shore. Mann-Whitney tests were performed, and the total amount of species turnover was calculated. A total of 518 individual fish from 57 species were recorded in the survey. The fish weight abundance was fivefold greater in the MMNP than in the unprotected areas. Fish abundance and diversity were higher in the MMNP than in the unprotected areas and decreased with distance from it. Our findings confirmed the importance of the protected area in conserving fish resources in Lake Tanganyika. The study provides baseline information for management of the resources and guiding future studies in the lake and other related ecosystems. Management approaches that foster awareness and engage with communities surrounding the MMNP are recommended for successful conservation of the resources in the region.
PubDate: Tue, 28 Jun 2016 12:22:19 +000
- Quality and Conservation of Riparian Forest in a Mountain Subtropical
Basin of Argentina
Abstract: The aims of this work were to describe the conservation status of riparian forests located in a mountain subtropical basin of Tucumán province, Argentina, and assess how the quality of riparian forests is related with altitude, plant species richness, proportion of exotic species, and Total Suspended Solids (TSS) in adjacent rivers. Composition and species richness of riparian forests were studied at 16 sites located along an altitudinal gradient and TSS was determined from water samples collected in each site. In order to evaluate conservation status of riparian forests, we calculated an index of Quality of Yungas Riparian Forests (QBRy). We recorded 90 plant species at all sites, from which 77% were native. QBRy index was mainly associated with altitude and varied from riparian forests with good preservation or slightly disturbed to those with extreme degradation. At lower altitude, forests were more disturbed, more invaded by exotic plant species, and closer to urban and cropped areas. QBRy was not correlated with species richness or TSS. Like other riparian forests of Argentina, plant species invasion increased their degradation; therefore, future studies should focus on native riparian forests conservation and on the management of invasive plant species, which affect their quality.
PubDate: Tue, 14 Jun 2016 10:43:17 +000
- Lake Baikal Ecosystem Faces the Threat of Eutrophication
Abstract: Recently there have been reports about large accumulations of algae on the beaches of Lake Baikal, the oldest and deepest freshwater body on earth, near major population centers and in areas with large concentrations of tourists and tourism infrastructure. To evaluate the observations indicating the ongoing process of eutrophication of Lake Baikal, a field study in July 2012 in the two largest bays of Lake Baikal, Barguzinsky and Chivyrkuisky, was organized. The study of phytoplankton using the sedimentary method and quantitative records of accumulations of macrophytes in the surf zone was made. In Chivyrkuisky Bay, we found the massive growth of colorless flagellates and cryptomonads as well as the aggregations of Elodea canadensis along the sandy shoreline (up to 26 kg/m2). Barguzinsky Bay registered abundantly cyanobacterial Anabaena species, cryptomonads, and extremely high biomass of Spirogyra species (up to 70 kg/m3). The results show the presence of local but significant eutrophication of investigated bays. To prevent further extensions of this process in unique ecosystem of Lake Baikal, the detailed study and monitoring of the coastal zone, the identification of the sources of eutrophication, and the development of measures to reduce nutrient inputs in the waters are urgently needed.
PubDate: Tue, 24 May 2016 14:28:43 +000
- Environmental Determinants Influencing Fish Community Structure and
Diversity in Two Distinct Seasons among Wetlands of Northern Region
Abstract: Fish community structure was assessed in six wetlands using cast nets, to correlate with environmental variables with diversity and distribution patterns, from 2010 to 2012. A total of 2,239 individuals belonging to 44 species and 1,938 individuals belonging to 40 species were sampled in the dry and wet seasons. Mochokid and Mormyrid families dominated fish community and constituted 14.8%, respectively, followed by Alestids (12.9%) and Chlariids (11.1%). Rarer taxons were centropomids, channids, malapteruds, and oesteoglossids and represented 1.9%, respectively. Overall, CPUE per net did not vary significantly (Tukey HSD test, ) in the dry and wet seasons. Wuntori marsh consistently showed dominance in mean monthly CPUE per net (dry = ; wet = seasons), while Bunglung constructed wetland was the least recorded (dry = ; wet = seasons). Fish diversity and richness differed significantly (, ) among seasons. Environmental disturbances were season-specific and did not differ significantly (, , ) among sites. A DCA ordination explained 69% variability in fish distribution patterns, while PCA showed that 81.8% of nitrate-nitrogen, phosphate, and grazing intensity on axis 1 and conductivity, temperature, and turbidity on axis 2 influenced fish community structure. Wetland conservation must be promoted to sustain fish abundance and overall ecosystem stability.
PubDate: Wed, 18 May 2016 12:52:25 +000
- Seasonal Fluctuation of the Population and Characterization of Bacillus
spp. Isolated from the Coastal Soils of Digha, West Bengal, India
Abstract: Seasonal fluctuation of the population of Bacillus spp. in the coastal soils of Digha, West Bengal, India, was determined and it has been found that, during summer, monsoon, and winter season, the Bacillus population density varied in the range of 0.01–0.236 × 106, 0.11–0.202 × 106, and 0.098–0.155 × 106, respectively. Two-way ANOVA, agglomerative hierarchial cluster (AHC) analysis, and principal component analysis (PCA) were performed to determine the diversity of Bacillus spp. in both spatial and temporal aspects. During summer season, the population of Bacillus spp. reached a comparatively higher density than monsoon or winter. Spatial variation was also exhibited among the Bacillus spp. in different coastal villages. A total of 25 strains of Bacillus spp. (DSB1–DSB25) were isolated from the coastal soils of different village areas of Digha, during the study period. The isolates were characterized morphologically, physiologically, and biochemically. Colony morphology of each of the isolates was thoroughly studied. Biochemical tests along with fermentation tests, NaCl, pH, and temperature tolerance tests were done. The antibiotic sensitivity of the isolated Bacillus spp. against different standard antibiotics was also assessed. The study revealed that the coastal soils of Digha area were rich in different strains of Bacillus spp. showing significant differences in the morphophysiological and biochemical properties.
PubDate: Thu, 12 May 2016 09:54:05 +000
- Potential Germination Success of Exotic and Native Trees Coexisting in
Central Spain Riparian Forests
Abstract: We compared potential germination success (i.e., percentage of produced seeds that germinate under optimal conditions), the percentage of empty and insect-damaged seeds, germinability (), and time to germination () between the exotics Ailanthus altissima, Robinia pseudoacacia, and Ulmus pumila and two coexisting native trees (Fraxinus angustifolia and Ulmus minor) in the riparian forests of Central Spain. Additionally, we tested the effect of seed age, seed bank type (canopy or soil) and population on and of A. altissima and R. pseudoacacia, which are seed-banking species. Species ranked by their potential germination success were A. altissima > U. pumila > R. pseudoacacia > U. minor > F. angustifolia. The combination of a high and negligible seed insect-damage provided A. altissima with a potential germination advantage over the natives, which were the least successful due to an extremely high percentage of empty seeds or a very low . R. pseudoacacia showed high vulnerability to insect seed predation which might be compensated with the maintenance of persistent seed banks with high . and were strongly affected by seed age in the seed-banking invaders, but between-seed bank variation of and did not show a consistent pattern across species and populations.
PubDate: Sun, 10 Apr 2016 12:00:08 +000
- Impact of Mass Bathing and Religious Activities on Water Quality Index of
Prominent Water Bodies: A Multilocation Study in Haryana, India
Abstract: The present study was designed to assess the impact of mass bathing and religious activities on water quality index (WQI) of prominent water bodies (eight) in Haryana, India. Water quality characteristics revealed significant increase in the values of nitrate, biochemical oxygen demand (BOD), turbidity, total dissolved solids (TDS), conductivity, total hardness, total alkalinity, and MPN count after the religious activities. The computed WQI at all the eight selected sites varied from 47.55 to 211.42. The results revealed that there was a significant increase in the value of WQI after mass bathing or any other ritual performed. Out of eight water bodies studied three (sites 3, 4, and 5) were found under good water quality status; four sites (1, 2, 6, and 7) depicted medium water quality but site 8 was found under poor water quality after the religious activities. The good water quality status of water bodies was correlated with larger size of the water bodies and less number of pilgrims; however, the poor WQI values may be attributed to smaller size of the water body and heavy load of pilgrims on such sites. Therefore, water of these religious water bodies needed to be regularly changed after mass bathing to protect the aquatic component from different contaminations.
PubDate: Wed, 02 Mar 2016 11:57:59 +000
- Species Richness, Community Organization, and Spatiotemporal Distribution
of Earthworms in the Pineapple Agroecosystems of Tripura, India
Abstract: The impact that plant communities may have on underground faunal diversity is unclear. Therefore, understanding the links between plants and organisms is of major interest. Earthworm population dynamics were studied in the pineapple agroecosystems of Tripura to evaluate the impact of monoculture plantation on earthworm communities. A total of thirteen earthworm species belonging to four families and five genera were collected from different sampling sites. Application of sample-based rarefaction curve and nonparametric richness estimators reveal 90–95% completeness of sampling. Earthworm community of pineapple agroecosystems was dominated by endogeic earthworms and Drawida assamensis was the dominant species with respect to its density, biomass, and relative abundance. Vertical distribution of earthworms was greatly influenced by seasonal variations. Population density and biomass of earthworms peaked during monsoon and postmonsoon period, respectively. Overall density and biomass of earthworms were in increasing trend with an increase in plantation age and were highest in the 30–35-year-old plantation. Significant decrease in the Shannon diversity and evenness index and increase in Simpson’s dominance and spatial aggregation index with an increase in the age of pineapple plantation were recorded. Soil temperature and soil moisture were identified as the most potent regulators of earthworm distribution in the pineapple plantation.
PubDate: Mon, 15 Feb 2016 13:00:10 +000
- Habitat Ecology and Ichthyofaunal Diversity of Two Creeks and Their
Associated Streams from Port Blair, South Andaman Islands
Abstract: Habitat ecology and ichthyofaunal diversity were analyzed from two creeks and their associated streams in Port Blair: one was perennial and the other one was seasonal. Various habitat types like riffles, pools, and major and minor bends in both streams were studied. The perennial stream has 12 riffles and 14 pools from head point to the entering point of the creek. The seasonal stream has 15 riffles and 13 pools from the starting point to the sink. The perennial stream was found to have higher ichthyofaunal diversity than the seasonal stream: 1701 individuals constituting 8 orders, 30 families, 42 genera, and 54 species were recorded. Among these, 395 specimens represented by 21 species were found in perennial stream, 291 specimens with 11 species were found in seasonal stream, 863 specimens by 48 species were noted in creek, and 152 specimens constituting 14 species in sink were recorded. The physicochemical parameters of the habitats showed more or less a similar trend. The average dissolved oxygen value of the perennial stream was higher than that of the seasonal stream. Higher temperature values were noted during the postmonsoon season. This study has indicated a wide lacuna in the knowledge of the fresh water habitats and their inhabitants on these islands.
PubDate: Thu, 04 Feb 2016 12:10:30 +000
- Assessment of Some Heavy Metals Pollution and Bioavailability in Roadside
Soil of Alexandria-Marsa Matruh Highway, Egypt
Abstract: To assess the roadside soils contamination with Pb, Cd, and Zn, 34 soil samples were collected along Alexandria-Marsa Matruh highway, Egypt, and analyzed by using the atomic absorption. The contamination with these metals was evaluated by applying index of geoaccumulation , contamination factor (CF), pollution load index (PLI), the single ecological risk index , and the potential ecological risk index (PERI). The average concentrations of Pb, Cd, and Zn were 38.2, 2.3, and 43.4 μg/g, respectively. indicates the pollution of soil with Pb and Cd as opposed to Zn. shows that the roadside soils had low risk from Pb and Zn and had considerable to high risk from Cd. Most of the samples (62%) present low PERI risk associated with metal exposure and the rest of the samples (38%) are of moderate PERI. The bioavailable fraction (EDTA-Extract) was 72.5 and 37.5% for Pb and Cd contents, respectively. These results indicate the remarkable effect of vehicular and agricultural activities on Pb and Cd contents in soil.
PubDate: Tue, 22 Dec 2015 13:31:26 +000
- Species Turnover across Different Life Stages from Seedlings to Canopy
Trees in Swamp Forests of Central Brazil
Abstract: Processes driving the assembly of swamp forest communities have been poorly explored. We analyzed natural regeneration and adult tree communities data of a swamp gallery forest in Central Brazil to discuss the role of ecological filters in shaping plant species turnover in a successional gradient. Species data of 120 plots were used to assess species turnover between natural regeneration and adult tree communities. Our analyses were based on 4995 individuals belonging to 72 species. Community patterns were discerned using ordination analyses. A clear floristic turnover among plant life stages was distinguished. Regeneration community of swamp forests was richer in species composition than the adult community. Tree species commonly found in nonflooded gallery forests were present in the regeneration plots but not in the adult community. Differences in the floristic composition of these two strata suggest that not all species in the seedling stage can stand permanent flooding conditions and only a few tolerant species survive to become adult trees. We propose that natural disturbances play an important role by altering limiting resources, allowing seeds of nonflooded forest species to germinate. This paper elucidates the turnover between plant life stages in swamp forests and suggests mechanisms that may shape these communities.
PubDate: Sun, 06 Dec 2015 11:46:58 +000
- 13C NMR and ESR Characterization of Humic Substances Isolated from Soils
of Two Siberian Arctic Islands
Abstract: Humic acids (HAs) and fulvic acids (FAs) of two Polar soils were investigated by 13C NMR and ESR spectroscopies, investigating the degree of humification and the molecular structure. One soil, from Bolshoi Lyakhovsky Island, contains two humus horizons: modern and buried. The other soil, from Wrangel Island, had only one modern humus horizon. The HAs and FAs of the two soils investigated show essential differences. The HAs show fewer oxygen-containing groups in comparison with the FAs, whereas the degree of aromaticity is two or three times higher in the HAs. The 13C NMR data also show that HAs are very different from FAs in terms of their molecular composition and hydrophobicity. Humification in the Arctic is limited by the very low content of lignin-derived compounds, due to the restricted vascular flora. As a result, the HAs, isolated from Polar soils, are more similar to the corresponding FAs than to the typical HAs of temperate soils. This was confirmed by ESR data, which show similar levels of free radical concentration for HAs and FAs and are related to the low level of aromaticity of both materials investigated. Apparently, the humification process in the soils of Polar Arctic deserts is in an initial stage.
PubDate: Thu, 12 Nov 2015 11:19:11 +000
- System Behaviour Charts Inform an Understanding of Biodiversity Recovery
Abstract: Practitioners working with species and ecosystem recovery typically deal with the complexity of, on one hand, lack of data or data uncertainties and, on the other hand, demand for critical decision-making and intervention. The control chart methods of commercial and industrial and environmental monitoring can complement an ecological understanding of wildlife systems including those situations which incorporate human activities and land use. Systems Behaviour Charts are based upon well-established control chart methods to provide conservation managers with an approach to using existing data and enable insight to aid timely planning of conservation interventions and also complement and stimulate research into wider scientific and ecological questions. When the approach is applied to existing data sets in well-known wildlife conservation cases, the subsequent Systems Behaviour Charts and associated analytical criteria demonstrate insights which would be helpful in averting problems associated with each case example.
PubDate: Tue, 10 Nov 2015 13:56:49 +000
- Combining Niche Modelling, Land-Use Change, and Genetic Information to
Assess the Conservation Status of Pouteria splendens Populations in
Abstract: To assess the conservation status of a species with little ecological information is usually a challenging process. Pouteria splendens is an endemic shrub of the coastal range of Central Chile currently classified as lower risk (LR) by IUCN (version 2.3). Knowledge about this species is extremely limited. Currently P. splendens is only found in two small and isolated populations, which are thought to be remaining populations of an originally large metapopulation. However, there is no evidence to support this hypothesis, limiting our ability to gauge the real current conservation status of this species. In this study we combine niche modelling, land-use information, and genetic techniques to test the metapopulation hypothesis and reassess the conservation status of P. splendens using the IUCN criteria. We also evaluated the potential effects of climate change in the species distribution. Our results support the hypothesis of a large metapopulation that was recently fragmented. Future climate could increase the range of P. splendens; however the high level of fragmentation would preclude colonization processes. We recommend reclassifying P. splendens as Endangered (EN) and developing strategies to protect the remaining populations. Similar approaches like the presented here could be used to reclassify other species with limited ecological knowledge.
PubDate: Tue, 10 Nov 2015 13:49:32 +000
- Recuperation of the Terra Firme Forest Understory Bird Fauna Eight Years
after a Wildfire in Eastern Acre, Brazil
Abstract: The present study evaluated the characteristics of the understory bird fauna of four fragments of terra firme forest in eastern Acre, Brazil, that were impacted by wildfires in 2005. The study investigated the species richness and the composition of trophic guilds using mist-netting on eight transects (four in burned plots and four in control plots in the same forest fragments). Eight plots (0.12 ha) were also established parallel to each transect to record the number of live trees (DBH ≥ 10 cm), palms, and dead trees. Bamboo stems were quantified in 0.024 ha subplots. No significant difference was found between burned and control plots in the species richness or abundance of birds, nor was any significant pattern found in the NMDS ordination of the composition of the communities or guilds. The Principal Components Analysis (PCA) found that the burned plots were physiognomically distinct, due principally to the number of bamboo stems and dead trees. Multiple regressions based on the PCA scores and bird species richness and abundance found no significant trends. The findings of the present study indicate that the understory bird assemblage of the areas affected by a single wildfire in 2005 had almost totally recuperated eight years after this event.
PubDate: Sun, 08 Nov 2015 07:09:18 +000
- Effects of Tree Shelters on the Survival and Growth of Argania spinosa
Seedlings in Mediterranean Arid Environment
Abstract: The argan tree is endemic species of Morocco. It occupies an area of more than 8700 km2 and plays essential ecological and economical roles. In spite of their value, the argan woodlands are subject to rapid and uncontrolled degradation during the last decades, mainly due to overgrazing and systematic collection of argan nuts. The present study was carried out to investigate the effects of two types of tree shelters on survival and growth of Argania spinosa seedlings planted in the southwest of Morocco in order to improve the results of reforestation programs which usually end by repeated failures. The experiment was conducted in the Mesguina forest for two growing seasons after transplantation in the field. After two years, the use of tree shelters significantly increased tree survival and allowed a gain of 20%. Height growth was positively affected by tree shelters. The use of tree shelters showed no significant decrease in basal diameter. In contrast, the height to diameter ratios of sheltered trees were much higher compared to the control. Thus, the use of the tree shelters could aid the early establishment and growth of Argania spinosa under conditions similar to those of the experiment.
PubDate: Wed, 04 Nov 2015 11:44:10 +000
- Nonconsumptive Effects of Predation and Impaired Chemosensory Risk
Assessment on an Aquatic Prey Species
Abstract: Weak levels of acidity impair chemosensory risk assessment by aquatic species which may result in increased predator mortalities in the absence of compensatory avoidance mechanisms. Using replicate populations of wild juvenile Atlantic salmon (Salmo salar) in neutral and acidic streams, we conducted a series of observational studies and experiments to identify differences in behaviours that may compensate for the loss of chemosensory information on predation risk. Comparing the behavioural strategies of fish between neutral and acidic streams may elucidate the influence of environmental degradation on nonconsumptive effects (NCEs) of predation. Salmon in acidic streams are more active during the day than their counterparts in neutral streams, and are more likely to avoid occupying territories offering fewer physical refugia from predators. Captive cross-population transplant experiments indicate that at equal densities, salmon in acidic streams do not demonstrate relative decreases in growth rate as a result of their different behavioural strategies. Instead, altering diel activity patterns to maximize visual information use and occupying relatively safer territories appear sufficient to offset increased predation risk in acidic streams. Additional strategies such as elevated foraging rates during active periods or adopting riskier foraging tactics are necessary to account for the observed similarities in growth rates.
PubDate: Wed, 28 Oct 2015 09:48:47 +000
- Tree Diversity and Community Composition of the Tutong White Sands, Brunei
Darussalam: A Rare Tropical Heath Forest Ecosystem
Abstract: Bornean heath (Kerangas) forests are a unique and increasingly rare tropical forest ecosystem that remains little studied. We quantified tree floristic diversity in Kerangas forests in the Tutong White Sands, Brunei Darussalam, and investigated the influence of soil and environmental variables on community composition. Six 20 m × 20 m plots were established, where all trees of ≥5 cm diameter at breast height (DBH) were identified and measured to determine stem diameter and basal area. We determined pH, gravimetric water content, and concentrations of total nitrogen (N) and phosphorus (P) in topsoil, as well as litter depth and percentage canopy openness. A total of 296 trees were recorded, representing 78 species in 59 genera and 38 families. Stem diameter, basal area, species richness, and species diversity differed significantly among the six plots. The NMDS ordination revealed that differences in tree community compositions were significantly associated with total N concentrations and percentage canopy openness. Despite the small sampling area, we recorded several Bornean endemic tree species (16/78 tree species; 20.5%), including several IUCN Red List endangered and vulnerable species. Our results illustrate the potentially high conservation value of the Kerangas forests in the Tutong White Sands and highlight the urgent need to protect and conserve this area.
PubDate: Tue, 27 Oct 2015 13:52:37 +000
- Ecological Determinants of Forest to the Abundance of Lutzomyia
longiflocosa in Tello, Colombia
Abstract: Lutzomyia longiflocosa is considered the most likely vector of cutaneous leishmaniasis in the sub-Andean region of the upper valley of the Magdalena River between 1,000 and 2,000 meters in the Department of Huila, Colombia. L. longiflocosa is anthropophilic, has endophagic behavior, and is especially important since its dominance in epidemics recorded in the last decade in the departments of Huila, Tolima, and the outbreak in Norte de Santander. The aim of our work is to identify ecological determinants in forest microhabitat level defining the abundance of L. longiflocosa. We use sampling; this was performed in 56 microhabitats of 28 forests with CDC traps for two consecutive nights from 18:00 to 06:00 hours. Each microhabitat (favorable and unfavorable) was located 10 m from the ecotone, with an approximate area of 10 m2. Thirty-five variables were examined as potential explanatory variables which were recorded in each microhabitat. Regression models were used to identify ecological determinants. Our results confirm that there are favorable microhabitats in the forest with specific ecological determinants that define the aggregated distribution of the species and provide the conditions necessary for survival and abundance of L. longiflocosa.
PubDate: Mon, 28 Sep 2015 08:27:39 +000
- Cervus elaphus Foraging Impacts on Plants and Soils at an Ungrazed Desert
Grass/Shrubland in Northwestern New Mexico, USA
Abstract: We evaluated Cervus elaphus herbivory and trampling impacts on plants and soils on Chaco Culture National Historical Park (Chaco), a desert grass/shrubland in northwestern New Mexico, USA, most (63%) of which has been protected from grazing by domestic livestock since 1948. We conducted grazing, browse, and water infiltration surveys in areas which received different amounts of C. elaphus use (use and control), 2004–2007. Browse utilization was
PubDate: Tue, 08 Sep 2015 16:38:53 +000
- Home Range, Diet, and Activity Patterns of Common Marmosets (Callithrix
jacchus) in Very Small and Isolated Fragments of the Atlantic Forest of
Abstract: We evaluate the impact of very small and isolated forest fragments on the common marmosets home range, diet, and activity patterns, in the northeastern Atlantic Forest of Brazil. Three groups were studied in three forest fragments, from January to October 2010, totaling 360 hours of observations and 1,080 field-hours. Systematic observations were recorded using Instantaneous Scan Sampling, and a checklist of the items exploited was built through ad libitum observations. We recorded location of the groups and calculated home range. We recorded 11,639 scans and 236 ad libitum feeding records. 83.4% () of food items were plant species, the only animal protein was from insects (; 16.6%), and the diet was based almost exclusively on gums. Mean home range was 5.5 ha, mean daily path length was 1,167 meters, and no differences were detected between seasons. Resting dominated their activity budget and varied between seasons. Common marmosets survived in this environment through a remarkable increase in their exploitation of tree gums (up to 98% of their feeding bouts) to compensate for the lack of food, in home ranges slightly larger than in the literature. Thus, they travelled and foraged less than expected and rested more since food was easily obtained.
PubDate: Tue, 18 Aug 2015 06:24:46 +000
- Changes in Allometric Attributes and Biomass of Forests and Woodlands
across an Altitudinal and Rainfall Gradient: What Are the Implications of
Increasing Seasonality due to Anthropogenic Climate Change?
Abstract: Canonical correspondence analysis and linear regressions were used to relate height, diameter, and dispersion measurements of 36,380 stems from 197 species recorded in 2,341 plots against both climatic and landscape variables. Above ground biomass increased in wetter and cooler locations that ameliorate the seasonal rainfall deficits. Taller and greater diameter trees with lower wood densities occur at higher altitudes. Differences between locations are based on a change in the composition of species rather than a change in the allometric properties within a species. The results support the hydraulic limitation and species packing hypotheses. These interrelationships may be affected by the interactions of fire frequency and drought which are a common feature of much of the study area. Under current climate change scenarios it is likely that there will be a reduction in above ground biomass, the number of stems per hectare, average height, average diameter, and basal area due to increasing seasonality of rainfall, temperatures, and the intensity and frequency of fires. The largest of trees are likely to be removed early due to their inability to cope with increased drought stress. The results suggest a marked reduction in carbon storage will occur across the study region in eastern Australia.
PubDate: Tue, 28 Apr 2015 11:51:56 +000
- Seasonality of Climate Drives the Number of Tree Hollows in Eastern
Australia: Implications of a Changing Climate
Abstract: Tree hollow number is investigated across an altitudinal and climatic gradient in eastern Australia. The relationship between seasonal climate and local site factors to hollow number at a regional scale was investigated. Moisture retention, rainfall, and solar radiation during the summer period were the highest contributing factors to hollow number in the model presented. The relationship of hollow number with the significant variables was unimodal in nature with either extreme causing a decline within the region. The results indicate that increased seasonality of rainfall, solar radiation, and temperatures as predicted by anthropogenic climate change will cause a shift in the optimal location for hollow number. Change in tree hollows is reliant on taxonomic replacement through dispersal and establishment and subsequently time to allow individuals to mature. The reduction in this resource stimulated by changes in seasonality predicted within the ensuing decades is likely to cause a loss of hollows across the landscape with the resource not being replaced for hundreds of years. The number of hollows within a landscape may drastically reduce due to climate change alone irrespective of tree clearing rates.
PubDate: Wed, 08 Apr 2015 13:38:22 +000
- Modeling Aquatic Macroinvertebrate Richness Using Landscape Attributes
Abstract: We used a rapid, repeatable, and inexpensive geographic information system (GIS) approach to predict aquatic macroinvertebrate family richness using the landscape attributes stream gradient, riparian forest cover, and water quality. Stream segments in the Allegheny River basin were classified into eight habitat classes using these three landscape attributes. Biological databases linking macroinvertebrate families with habitat classes were developed using life habits, feeding guilds, and water quality preferences and tolerances for each family. The biological databases provided a link between fauna and habitat enabling estimation of family composition in each habitat class and hence richness predictions for each stream segment. No difference was detected between field collected and modeled predictions of macroinvertebrate families in a paired t-test. Further, predicted stream gradient, riparian forest cover, and total phosphorus, total nitrogen, and suspended sediment classifications matched observed classifications much more often than by chance alone. High gradient streams with forested riparian zones and good water quality were predicted to have the greatest macroinvertebrate family richness and changes in water quality were predicted to have the greatest impact on richness. Our findings indicate that our model can provide meaningful landscape scale macroinvertebrate family richness predictions from widely available data for use in focusing conservation planning efforts.
PubDate: Mon, 26 Jan 2015 06:53:47 +000
- Potential Effects of the Loss of Native Grasses on Grassland Invertebrate
Diversity in Southeastern Australia
Abstract: Reduction in area of the southeastern temperate grasslands of Australia since European settlement has been accompanied by degradation of remaining remnants by various factors, including the replacement of native plant species by introduced ones. There are suggestions that these replacements have had deleterious effects on the invertebrate grassland community, but there is little evidence to support these suggestions. In the eastern Adelaide Hills of South Australia, four grassland invertebrate sampling areas, in close proximity, were chosen to be as similar as possible except for the visible amount of native grass they contained. Sample areas were surveyed in four periods (summer, winter, spring, and a repeat summer) using pitfall traps and sweep-netting. A vegetation cover survey was conducted in spring. Morphospecies richness and Fisher’s alpha were compared and showed significant differences between sample areas, mainly in the summer periods. Regression analyses between morphospecies richness and various features of the groundcover/surface showed a strong positive and logical association between native grass cover and morphospecies richness. Two other associations with richness were less strong and lacked a logical explanation. If the suggested direct effect of native grass cover on invertebrate diversity is true, it has serious implications for the conservation of invertebrate biodiversity.
PubDate: Mon, 01 Dec 2014 07:42:30 +000