This document provides an investigation of vegetation dynamics on Aride Island since 1976, with a focus on the prevalence of Pisonia grandis trees. The investigation aims to observe changes in herbaceous diversity, tree demographics, and the continued dominance of P. grandis. Permanent vegetation plots established in 1976 will be revisited and new plots added. Data on plant cover, tree abundance, and canopy structure will be collected and analyzed using diversity indices and other statistical methods. Based on past reports, herbaceous diversity is expected to have declined as woodland has expanded. Tree diversity in the understory is also expected to be low due to shade tolerance of dominant species, while mid-upper canopies may be more diverse
Risks of Cryogenic Landslide Hazards and Their Impact on Ecosystems in Cold E...Universität Salzburg
Research focuses on monitoring landscapes downgrading in specific conditions of Arctic ecosystems with cold climate conditions (marshes, permafrost, high humidity and moisture). Specific case study: cryogenic landslides typical for cold environments with permafrost. Area: Yamal Peninsula. Aim: analysis of the environmental changes caused by cryogenic landslides in northern land- scapes affecting sensitive Arctic ecosystems. Thaw of the permafrost layer causes destruction of the ground soil layer and activates cryogenic landslide processes. After disaster, vegetation coverage needs a long time to recover, due to the sensitivity of the specific northern environment, and land cover types change. ILWIS GIS was used to process 2 satellite images Landsat TM taken at 1988 and 2011, to assess spatiotemporal changes in the land cover types. Research shown ILWIS GIS based spatial analysis for environmental mapping.
Presentation of the fall and rise and fall again of eastern hemlock, a foundation tree species of eastern North American forests. Testing the hypothesis that it is a foundation species, modeling its future given climate change scenarios, and validating model results with eddy covariance data
Species Diversity and Above-ground Carbon Stock Assessments in Selected Mangr...Innspub Net
Mangrove ecosystems are known for being the rainforest of the sea. Philippines is bestowed with this naturally rich mangrove ecosystem with diverse floral and faunal species. Despite this natural abundance, mangrove ecosystems are subjected to natural and human induced degradations specifically conversion to fish shrimp ponds that resulted in diminution aside from its effect on terrestrial and oceanic carbon cycling and could also affect its important role in terms of terrestrial and oceanic carbon cycling. This study is conducted to determine
the mangrove diversity, distribution and the above-ground biomass and C-stocks in Glan and Malapatan, Sarangani Province. Purposive sampling is implemented in establishing the plots on both sites. Results show eight (8) mangrove species belonging to four (4) families are observed in both areas. Data also reveal that the mangrove ecosystem in Glan Padidu, Glan is undisturbed. Rhizophora apiculata and Sonneratia alba are found to be dominant on the two sites. Because of the large tree girths and high density of species observed on the studied areas, both forests have the potential to sequester and store large amount of atmospheric carbon. Thus, this study quantifies mangrove tree biomass in view of carbon trading as significant in lessening the effects of global warming.
Risks of Cryogenic Landslide Hazards and Their Impact on Ecosystems in Cold E...Universität Salzburg
Research focuses on monitoring landscapes downgrading in specific conditions of Arctic ecosystems with cold climate conditions (marshes, permafrost, high humidity and moisture). Specific case study: cryogenic landslides typical for cold environments with permafrost. Area: Yamal Peninsula. Aim: analysis of the environmental changes caused by cryogenic landslides in northern land- scapes affecting sensitive Arctic ecosystems. Thaw of the permafrost layer causes destruction of the ground soil layer and activates cryogenic landslide processes. After disaster, vegetation coverage needs a long time to recover, due to the sensitivity of the specific northern environment, and land cover types change. ILWIS GIS was used to process 2 satellite images Landsat TM taken at 1988 and 2011, to assess spatiotemporal changes in the land cover types. Research shown ILWIS GIS based spatial analysis for environmental mapping.
Presentation of the fall and rise and fall again of eastern hemlock, a foundation tree species of eastern North American forests. Testing the hypothesis that it is a foundation species, modeling its future given climate change scenarios, and validating model results with eddy covariance data
Species Diversity and Above-ground Carbon Stock Assessments in Selected Mangr...Innspub Net
Mangrove ecosystems are known for being the rainforest of the sea. Philippines is bestowed with this naturally rich mangrove ecosystem with diverse floral and faunal species. Despite this natural abundance, mangrove ecosystems are subjected to natural and human induced degradations specifically conversion to fish shrimp ponds that resulted in diminution aside from its effect on terrestrial and oceanic carbon cycling and could also affect its important role in terms of terrestrial and oceanic carbon cycling. This study is conducted to determine
the mangrove diversity, distribution and the above-ground biomass and C-stocks in Glan and Malapatan, Sarangani Province. Purposive sampling is implemented in establishing the plots on both sites. Results show eight (8) mangrove species belonging to four (4) families are observed in both areas. Data also reveal that the mangrove ecosystem in Glan Padidu, Glan is undisturbed. Rhizophora apiculata and Sonneratia alba are found to be dominant on the two sites. Because of the large tree girths and high density of species observed on the studied areas, both forests have the potential to sequester and store large amount of atmospheric carbon. Thus, this study quantifies mangrove tree biomass in view of carbon trading as significant in lessening the effects of global warming.
Climatic variability and spatial distribution of herbaceous fodders in the Su...IJERA Editor
This study focused on future spatial distributions of Andropogon gayanus, Loxodera ledermanii and Alysicarpus
ovalifolius regarding bioclimatic variables in the Sudanian zone of Benin, particularly in the W Biosphere
Reserve (WBR). These species were selected according to their importance for animals feed and the
intensification of exploitation pressure induced change in their natural spatial distribution. Twenty (20)
bioclimatic variables were tested and variables with high auto-correlation values were eliminated. Then, we
retained seven climatic variables for the model. A MaxEnt (Maximum Entropy) method was used to identify all
climatic factors which determined the spatial distribution of the three species. Spatial distribution showed for
Andropogon gayanus, a regression of high area distribution in detriment of low and moderate areas. The same
trend was observed for Loxodera ledermannii spatial distribution. For Alysicarpus ovalifolius, currently area
with moderate and low distribution were the most represented but map showed in 2050 that area with high
distribution increased. We can deduce that without bioclimatic variables, others factors such as: biotic
interactions, dispersion constraints, anthropic pressure, human activities and another historic factor determined
spatial distribution of species. Modeling techniques that require only presence data are therefore extremely
valuable.
The rural-urban socioecological transformation of Mediterranean mountain areas under global change. Local studies in Olzinelles and Matadepera (Barcelona Metropolitan Region)
A numerical analysis of understory plant associations in a Pinus wallichiana ...Innspub Net
The present investigation describes the structure and vegetation composition of the forest located in Murree Hills, Punjab, Pakistan. The study area is a part of Himalayans moist temperate forest. The vegetation zone entirely consists of shrubs or medium size trees. The plants give the appearance of a vast flower bed, composed principally of herbaceous species. These species are adapted to withstand the extremes of cold and desiccation. Study area range in altitude from 2100m-2300 m (A.S.L.). A total of 65 species, belonging to 62 genera and 39 families were recorded from 40 stands. Angiosperms contributed a major share while Pteridophytes contributed little to the floristic richness of the area. Data were analyzed by multivariate statistics including Cluster Analysis, Detrended Correspondence Analysis (DCA) and correlation co-efficient to detect the relations between altitudinal and some environmental factors with composition and structure of the plant communities. DCA axis 1 and axis 2 were used to interpret the data. Four vegetation types were delineated by Cluster Analysis which was then plotted on the first two axes a scattered diagram. The outcome of the cluster was confirmed by using DCA. There were significant differences in the flora composition as well as the edaphic factors along the altitudinal gradient. The results of the present investigation suggest a direct altitudinal and soil chemical factors pH, EC, cations and anions on the vegetation variation. Topography predicts species composition of the study area.
Under the influence of the mass media development and tecnological changes in mass communications starting from the 70's, UNESCO promoted a concept to develop media and media literacy. Media literacy helps people for critical understanding and using media.
The understanding of the media and media habits are important components in establishing personal identity and socialization in the society.
Climatic variability and spatial distribution of herbaceous fodders in the Su...IJERA Editor
This study focused on future spatial distributions of Andropogon gayanus, Loxodera ledermanii and Alysicarpus
ovalifolius regarding bioclimatic variables in the Sudanian zone of Benin, particularly in the W Biosphere
Reserve (WBR). These species were selected according to their importance for animals feed and the
intensification of exploitation pressure induced change in their natural spatial distribution. Twenty (20)
bioclimatic variables were tested and variables with high auto-correlation values were eliminated. Then, we
retained seven climatic variables for the model. A MaxEnt (Maximum Entropy) method was used to identify all
climatic factors which determined the spatial distribution of the three species. Spatial distribution showed for
Andropogon gayanus, a regression of high area distribution in detriment of low and moderate areas. The same
trend was observed for Loxodera ledermannii spatial distribution. For Alysicarpus ovalifolius, currently area
with moderate and low distribution were the most represented but map showed in 2050 that area with high
distribution increased. We can deduce that without bioclimatic variables, others factors such as: biotic
interactions, dispersion constraints, anthropic pressure, human activities and another historic factor determined
spatial distribution of species. Modeling techniques that require only presence data are therefore extremely
valuable.
The rural-urban socioecological transformation of Mediterranean mountain areas under global change. Local studies in Olzinelles and Matadepera (Barcelona Metropolitan Region)
A numerical analysis of understory plant associations in a Pinus wallichiana ...Innspub Net
The present investigation describes the structure and vegetation composition of the forest located in Murree Hills, Punjab, Pakistan. The study area is a part of Himalayans moist temperate forest. The vegetation zone entirely consists of shrubs or medium size trees. The plants give the appearance of a vast flower bed, composed principally of herbaceous species. These species are adapted to withstand the extremes of cold and desiccation. Study area range in altitude from 2100m-2300 m (A.S.L.). A total of 65 species, belonging to 62 genera and 39 families were recorded from 40 stands. Angiosperms contributed a major share while Pteridophytes contributed little to the floristic richness of the area. Data were analyzed by multivariate statistics including Cluster Analysis, Detrended Correspondence Analysis (DCA) and correlation co-efficient to detect the relations between altitudinal and some environmental factors with composition and structure of the plant communities. DCA axis 1 and axis 2 were used to interpret the data. Four vegetation types were delineated by Cluster Analysis which was then plotted on the first two axes a scattered diagram. The outcome of the cluster was confirmed by using DCA. There were significant differences in the flora composition as well as the edaphic factors along the altitudinal gradient. The results of the present investigation suggest a direct altitudinal and soil chemical factors pH, EC, cations and anions on the vegetation variation. Topography predicts species composition of the study area.
Under the influence of the mass media development and tecnological changes in mass communications starting from the 70's, UNESCO promoted a concept to develop media and media literacy. Media literacy helps people for critical understanding and using media.
The understanding of the media and media habits are important components in establishing personal identity and socialization in the society.
#BR4041UL is a Broadening programme looking at Social Media for the Social Good. This is a background lecture on gamification, from definitions to criticisms to design considerations.
Water-related bird assemblages in an urban pond ‘archipelago’: Winter pattern...Maria Paola Di Santo
This study reports on the patterns of species occurrence, abundance and richness of a wintering water-related bird assemblage in an ‘archipelago’ of 70 small artificial urban ponds (AUPs) embedded in a metropolitan landscape (Rome, central Italy). A total of 20 species in 26 AUPs were sampled. Only the largest AUPs (>0.1 ha) contained all these species, except for Gallinula chloropus. The highest total mean species abundance was observed in the largest ponds, with statistically significant differences evident among size classes. Two significant spatial thresholds in species abundance and richness were observed (between 0.01 and 0.1 ha; between 0.1 and 1 ha in size). The abundance of single species was correlated with their frequency of occurrence. Ponds in urban areas must be larger than 0.1 ha to host a rich winter assemblage of birds, with a further increase in richness noted with a surface area larger than 1 ha. The highest number of species was observed in the larger ponds (>1 ha). The species richness of each AUP is directly correlated to their size (log-transformed species–area relationship: log S = 3.515 + 0.497 log A; R2 = 0.76). Further research should be conducted to confirm these patterns and to implement information useful for planning and management of artificial ponds in urban areas for this purpose.
Needingworth Quarry is the location for an exciting wetland restoration project arising from a collaboration between Hanson and the RSPB. As gravel extraction is completed in sections of Needingworth these areas are being restored into wetland habitats, including large areas of reedbed and associated rough grassland, which has been named Ouse Fen Nature Reserve. Reedbed restoration sites, typified by Needingworth also include areas of wet or dry rough grassland, with varying degrees of management through grazing, mowing and fencing. These grasslands in themselves potentially provide a valuable habitat for biodiversity, especially given the context of the considerable intensification of agricultural and other grasslands that has taken place over recent decades.
In this project we propose to investigate the insect biodiversity of grasslands surrounding the reedbed restoration units at Needingworth/Ouse Fen. The focus of our work will be the leafhoppers (Auchenorrhyncha), which are common in grassland and have been found to be useful indicators of management intensity effects. In particular we are interested in how leafhoppper communities are affected by the level of grazing by cattle and how they vary with distance from the reedbeds and open water. The principal objective is to increase our knowledge of insect communities in these habitats at Needingworth/Ouse Fen and to inform management practice decisions in relation to these grasslands, which it is hoped will help to further enhance the biodiversity value of the restoration.
The project won the 1st Prize in National Quarry Life Award in 2014 in the United Kingdom.
Read more: http://www.quarrylifeaward.com/project/investigation-insect-biodiversity-grasslands-surrounding-reedbed-restoration-needingworth
Nechisar park gis based conservation assesmentAsaye Nigussie
ANALYSIS OF LAND AND VEGETATION COVER DYNAMICS
USING REMOTE SENSING & GIS TECHINIQUES,A CASE
STUDY OF NECHISAR NATIONAL PARK
Abstract
The research aims to analyze the trend of land and vegetation cover dynamics over the period from 1976, 1986 2000 and 2007 thus examine the conservation status of the area and generate
up-to-date land cover map. Information is extracted from various Satellite images of multidated Landsat, ASTER and MODIS images. The Landsat images are the basic remote sensing data to generate the thematic maps which are further analyzed to show the cover dynamics in the park for 24years. All datas from the satellite images are processesed and analyzed using digital image processing techniques. Besides, different vector data are extracted from the images as well as other thematic maps. MODIS-NDVI images are analyzed for the different land cover classes and each vegetation cover seasonal response is compared for the year 2000 and 2005.
The land cover classes identified in the study area from 1976, 1986, 2000 and 2007 are water body, riparian and ground water (GW) forest, wood land, dense bush land, bushy shrubbed grass land, open grass land, degraded grass land, cultivated land, swamp vegetation and bare
land. Rate of land cover change and fragmentation of habitat were discussed for the different
land cover classes. Rate of land cover change, fragmentation index and land cover conversion
matrix clearly shows the dynamics of the different cover classes has happened for the past decades and generally the park conservation status is found to be poor. Bush encroachment in the study area is a major challenge to the park particularly for the grass land and overgrazing
on the Nechisar plain has caused expansion of invasive plants erosion and land degradation.
The community livelihood dependency both in the rural and urban setting is concluded and discussed as a challenge to the park from biodiversity conservation point of view.
Key Words: Land cover dynamics, National park, Vegetation cover, Remote sensing and GIS,
Habitat fragmentation, degradation, biodiversity conservation.
THE EFFECTS OF CLEARCUT SIZE ON THE BIRD COMMUNITY IN THE SECOND COLLEGE GRANTjoshmooney
Abstract. This study examines the effects of forest opening (clearcut) size on the surrounding forest-bird community with the objective of offering management suggestions for foresters who employ the clearcut method. I hypothesized that large and small clearcuts would have different effects on the forest-bird assemblage associated with each. I used the point-count method to assess bird abundance in clearcuts, on the edges, and 100 m into the forest from the edges of large and small clearcuts. I found that Neotropical migrant birds and forest-interior birds were the most affected by large clearcuts showing significantly lower abundance in forest areas 100 m from large clearcut edges than in forest areas 100 m from small clearcuts. Edge-open birds were more abundant in large clearcut openings and edges than in small clearcut openings and edges. Blue jays (an avian nest predator) were more abundant on the edges of large clearcuts than on the edges of small clearcuts. A recent study found that forest-interior bird abundance levels off after 100 m distance from small (0.4 ha) forest openings. This result combined with my findings suggest that small openings in the Second College Grant represent less of a disturbance to Neotropical migrants and forest-interior birds. Additionally, given higher abundances of an avian nest predator in large clearcuts, reproductive success could be much lower in areas associated with large clearcuts. Some species such as the White-throated Sparrow (Zonotrichia albicollis), however preferred large clearcuts suggesting that there are some benefits to overall bird abundance by including large clearcuts in a managed landscape.
Reptile Diversity in Mt. Matutum Protected Landscape, South Cotabato, Philipp...Innspub Net
Reptiles are highly diversewith high percentage of endemism in the Philippines. However, reptile diversity in Mindanao, the second largest island in the country,is poorly known. To determine the species richness, diversity, endemism and conservation status of reptiles, this study was conducted from August to December 2013in six sampling sites of Mt. Matutum Protected Landscape (MMPL), South Cotabato.Cruising methodwasdone in the six sampling sites of MMPL. Paleontological Statistics Software Package (PAST) version 3.06 was used to determine the biodiversity indices, similarity index, and Kruskal-Wallis test. Thirteen species of reptiles belonging to five families and 11 genera with percentage endemism of46.15% were documented. High species diversity of reptiles with more or less even distribution was recorded in MMPL. Among the sampled sites, sampling site 1, a disturbed lowland dipterocarp forest had the highest species diversityand endemism.Sphenomorphusvariegatus was the most abundant species. Tropidophoruspartelloi, the only Mindanao Island endemic species was only found in the disturbed and undisturbed montane forests. Most of the documented species were under the Least Concern status. Bray-Curtis cluster analysis showed that sites 2 and 5 had the highest similarity percentage (68%) while Kruskal-Wallis test showed no significant difference between samples in disturbedand undisturbed sites. Threats to the reptiles of MMPL were observed to be the conversion of forest to farmland and hunting thus implying the need for protection of habitats and conservation of species in MMPL.
Seasonal Phenology of Reptiles in a Mediterranean Environment (“Castel di Gui...IJEABJ
The present work reports the seasonal phenology of the reptiles of the "Castel di Guido" Natural Park near Rome (Northern Latium, Italy). During field observations, between September 2014 and July 2016, transects were carried out along the ecotones of the park, in order to describe the period of seasonal activity of the reptiles present. The area is characterized by Mediterranean mesothermal climate. In the Mediterranean area, reptiles have a broader annual activity range than other European regions, greatly reducing winter latency. Reptile activities start very early, in some case it is possible to observe the snake Hierophis viridiflavus and lizards, such as Podarcis muralis and Podarcis siculus, in thermoregulation activity in the middle of winter. The mild climate that is recorded on average in autumn favors the activity in the period between September and December; Zamenis longissimus is observed regularly in October. Testudo hermanni mates regularly in autumn and it is active until the first decade of December. The research shows that during the winter period reptiles can be observed in activity; for some species, Chalcides chalcides, Podarcis sp., Hierophis viridiflavus, this seems to be a remarkable datum that broad considerably the annual phenology reported in the literature.
Agrosilvopastoral Systems A Practical Approach Toward Sustainable Agricultur...
An investigation of the vegetation dynamics on Aride
1. Euphorbia Encroachment
An investigation of the vegetation dynamics on
Aride Island since 1976, with special
consideration to the prevalence of Pisonia
grandis
Introduction
Aride is a small 72ha granitic Island situatedinthe
northern groupof the Seychelles, 4° southof the
Equator. It is consideredto be the most diverse and
harbours the greatest abundance of native plants of all
the granitic group(Fursinger andPutallaz, 2008). Due
greatlyto the management techniques of the Island’s
wardens large areas of the hills are still absent of
introduced species, thus maintainingthe Bwa Mapu
forests (Pisonia grandis) that are both prevalent and
unique to this granitic archipelago.
Nevertheless, its colonial past saw considerable
alterations to vegetation composition, which mayhave
causedlasting effects for the repopulation ofcertain
slower colonisingspecies. The plateauwas cleared to
cater for coconut (Cocos nucifera) plantations, whilst
extensive coppicing occurred onthe Island’s hill
vegetationto artificiallyincrease the number of Sooty
Terns, (Sterna fuscata) nesting, withtheir eggs being
soldas a cultural delicacyon the neighbouringisland of
Praslin (Fursinger and Putallaz, 2008). Aride was
declareda nature reserve in1973, following its
ownershipbythe Cadburyfamily, initiallyto protect
breedingcoloniesof over a millionseabirds. However
given its unique ecosystem, extensive habitat
management andmonitoring hasbeen undertakenin an
attempt to returnAride’s vegetationbackto the native
coastalforest, which existedprevious to human
intervention.
In the first 20years of becoming a nature reserve the
amount of mature woodlandmore thandoubled in size,
with climatic speciesindicative of native woodland:
Euphorbia, Ficus reflexa, Ficus nauticum and specifically
Pisonia, recolonising the hillside environment. Yet this
increase inwoodlanddiversity, naturally[1] resultedin a
decrease of the more diverseglade habitat. As the
canopyspreadit reduced the abundance of light, to the
advantage of shade tolerant groundflora;namely
Nephrolepis which have spreadand become a dominant
under-canopylayer ofthe hillside habitat.
Of all the trees on Aride, Pisonia grandis has become the
most dominant, accounting for over 80% of the lead
trees[2], withclusters ofmonospecific stands scattered
across the hillside environment (Fursinger and Putallaz,
2008). It is a prevalent pioneer species and
consequentiallyhas traits whichenable it to dominate
the earlystages ofwoodland successionon a small
island: fast andefficient vegetative propagation,
tolerance to salt spray, shallowsoil and slope, and like
Ficus are typicallyfaster growing andtaller than
Rothmannia and Euphorbia. Despite these advantages,
as is the case withmost pioneer species, Pisonia has a
short life cycle of roughly30years. It canthus be
assumed that competing species witha distinct
longevitywill outcompete in time.
Figure 1: flow diagram manipulated from Ayrton (1994) illustrating
general vegetative succession on hill-slope glades.
[1] Natural succession dictates that with a transition to mature woodland
biodiversity declines as shade becomes a greater limiting factor in the growth of the
now understorey species.
[2] A lead tree is defined as that which contributes most to the woodland canopy
Asystasia Encroachment
Pisonia Encroachment
Euphorbia canopy develops at a
slower rate allowing light to
penetrate the understorey and
species diversity persists
Cyperacae/Graminae
DominatedGlade
Ficus sp. slowly encroach whilst
Pisonia canopy increases in
height and density. shade
tolerant species namely
Nephrolepis become dominant
ground flora, invading in swades.
Fallen Pisonia may propogate
reulting in low Pisonia scrub in
areas.
Asystasia Dominated Glade
Canopy cover increases and
ground flora diminish as light
becomes limited. Cyperacae and
Graminae sp. most notiably
decline whilst Asystasia is lost
under the denser canopies
Species diversity slowly declines
as canopy develops. In rocky
slopes Euphorbia often stay
dominant, whilst Pisonia will
invade where conditions are
more favourable and potentially
encroach further. Nephrolepis
may spread, although ground
cover will remain low as
conditions often not optimal
2. Project Description
The aim of the present investigationis to observe and
where possible quantify anychanges that have occurred
in herbaceous and structural diversity, tree
demographics andas a bi-product examine the
continued prevalence of Pisonia grandis. This will be
accomplishedbyre-visitingthe permanent vegetation
plots set up in 1976 byWarmanet, al. (1976), which
have not been statisticallyanalysed since the turnof the
century. Despite there being a detailedmethodologyof
how to sample the plots in the initial 1976 report that
will be usedas a core manual, a collectionof other
sampling techniqueswill be usedto tailor the data
collected, especiallyinrelationto tree demographics.
These additional methods are simplymade upof
subsequent collectionefforts on Aride that have seemed
successful, along with previous experience inquantifying
speciesdiversities withindices.
According to past reports (list) it wouldbe expectedthat
herbaceous diversityon the islands has continuedto
decrease as the vegetationprogressivelyshrinks glade
habitats inits successionto woodland. It wouldfurther
be expectedthat whilst the understory canopywillhave
a low structural diversitygiventhe dominance andoften
monospecific nature of shade tolerant species, the mid
and upper-storeycanopiesshouldin theoryprove more
complex. The woodland shouldhave naturallyincreased
in height whilst younger trees andsapling will have
colonised available gaps to create heterogenic stands in
relationto age;although likelynot species.
General objectives:
To relocateprevious permanentquadrats and add several
new ones toincreasedata stock and representation.
Carry out appropriatesampling as permethodology.
Provide statistically sound comparisons withprevious
data wherepossible.
Provide some currentconclusionsabout Aride’svegetation to
contribute tofuture monitoring and management
programmes.
In-Field Methodology
The method for investigating the permanent quadrats
(Warman, et al 1976) canbe foundsummarised onthe
back of the laminatedmap ofthe original permanent
vegetationplots;made in2011.
In relationto this investigation some minor alterations
were made andwill be briefly summarised(see field
data sheet Appendix 1 for clarification):
1) The previous permanent plots, or the area which
best fits their location(inaccordance withthe map
generatedin2011) were relocatedanda 10mx10m
plot was either re-establishedor established
(depending onwhat remains of the previous plot).
2) The GPS was usedto note Altitude andthe
SoutherlyandEasterlycoordinates, whichwhen
accompaniedbythe gridreference from the map
should facilitate the re-locationprocess.
3) A quick sketch anddescription of the site was then
carriedout to highlight the significant site
characteristics i.e. large boulders, rare speciesor
the general vegetation layout.
4) All the trees withinthe plot were recordedina
specieslist and eachallocated 3 abundance classes:
for saplings, for adults andanaggregate (fieldsheet
shows abundance scale). Thisscale was usedas a
means to imbalance the weighting towards less
abundant species. Inaddition the 4 leadtreeswere
noted andmapped.
5) The canopyat three levels (<0.5m,0.5-2.5m,>2.5m)
was thenassessedproviding anestimated
percentage cover at eachlevel. The 3 species which
contribute greatest to these canopies were
recordedalong witha contributionpercentage.
6) Thirteen 1mx1m quadrats were placedin a “X”
pattern across the larger plot, with sub-plot A top-
left, D centre, G bottom-right, H top-right andM
bottom-left. A percentage cover of abiotic and any
identifiedspecies was estimated[1] and anaverage
calculated.
[1] The total cover of a subplot including both abiotic elements and species can be
over 100% (as species cover may overlap due to height variations) or under 100%
(due to obstacles i.e. tree trunks).
3. Data Methodology
In analysingthe data severalcalculations were applied
to achieve measures of diversityandtree prominence,
with observations made of the canopycovers to indicate
structural complexity. Basic statistics includingmeans,
standarddeviation and normalitytests were run to
gather a general viewof the collated dated, whilst
regression analysis wasusedto indicate significant
relationships, their strength and direction. ANOVA could
not be used to signifysignificant differencesacross the
time as the data was either unavailable to deferred in
nature. As suchcomparisons were made from previous
observations andstatistical conclusions rather than
parallel analyses.
1) Data was input intoExcel® usingseparate
spreadsheets for percentage cover, canopyand
tree prominence (see Appendices B, CandD).
2) A Simpson’s diversityindex was thancalculated for
the island (onlytakinginto account herbaceous
species) using the equation:
1NN
1nn
D
ii
Where ni = the total number of organisms ofeach
individualspecies.
N = the total number of organisms of all species
The value of D rangesfrom 0 to 1. With 0 representing
infinite diversityand1 no diversity. That is, the bigger
the value the lower the diversity. Purelyfor aesthetic
purposes the value wasinverted(‘1-D’)sothat a larger
value indicatedgreater species diversity.
3) Using the abundance scores relative frequencyand
abundance was calculatedfor tree saplings, adults
and anaggregate of the two so that PVs[1] couldbe
determinedusing the equation:
𝑃𝑉𝑖𝑗 =
𝑓𝑖𝑗
∑ 𝑖𝑓𝑖𝑗
× 100% +
∑ 𝑘𝑎𝑖𝑗𝑘
∑ 𝑖 ∑ 𝑘𝑎𝑖𝑗𝑘
× 100
Where aijk denotesthe abundance class value of
speciesi in sampling unit k of plot j
Sapling andadult PVs for different species were
plotted ona scatter graphto forecast potential
demographic changes.
4) The canopydata wasthen coloured to signify
different species (>0.5m:red-P.grandis, blue-
E.pyrifolia, yellow- Ficus. Sp, green- R. annae). This
helped to highlight species differencesobservedin
the canopydata.
5) Regressionanalysis was performedcanopies of vary
height, along withother variables that shared a
likelyrelationship(either from observations made
in the fieldor from the data (or commonsense))
and proved to have a normal distribution.
[1] A Prominence Value (PV) is the sum of the relative frequency and relative
abundance of a species. It reaches a maximum value of 200.
8. Graphs 3.2a (top left), b (top right), c (bottomleft): scatter plots to demonstraterelationship between
thecanopy cover at thethreemeasuredlayers. Bothanalyses which including a canopy layer of>2.5m
could not besubjected to regressionanalysis dueto thelack ofnormality in thedata distribution,the
graphs arepresented as 3.2a andb. Nevertheless canopy layers 0.5m and 0.5m –2.5mprovedto have
a significant weak positiverelationship (Fs 29.3, DoF 1.6 and P<1%)withthelinear regressioncurve
provided in thegraph3.2b. Theresiduals weretested in a standardresidual plot anda normal quantile
plot as a means ofregression model diagnostic.
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9. Discussion of Results
Diversity
The Simpson’s diversityindex calculatedsolelyfrom the
understoreyherbaceous species was0.285, whichwhen
invertedcomesto 0.715. This wouldindicate that
Aride’s hillslope habitat (as basedon the 18 surveyed
plots) is moderatelyhigh. In additionthe glade
environments offer the greatest diversitydue to the
higher frequencyof species present, while steeper
rockier regions where the soil is shallow;yieldedthe
lowest diversitylevels. Incomparisonwithprevious
reports regardingAride’s diversity, it would appear that
it has remains relativelyconstant inthe past 10 – 15
years. Thisis surprising consideringthe forecasted
shrinkingand loss ofglade environments predicted in
previous studies. Correspondinglythe presence of
Asystasia gangetica, anindicator of glade habitats,
matches the trends discussedinthe 1996, witha
continueddecrease inspecies frequency. A likely
explanationfor the stagnated diversitylevel couldbe
derivedfromthe alternate measure of species cover,
adoptinga percentage cover method rather thana
simple present-or-absence recording. The more likely
explanation, and one which makes comparingdata sets
over the years relativelyredundant, is the additionof
the four newplots andthe lossof some of the past sites
to increase the distributionandthus environmental
representation.
Structural diversity
Despite the failures of statisticallyproving anysignificant
relationships between most of the canopylayers (given
the lackof normalityof the data distribution for the
higher canopylayer), trends can be observed when
specific speciesand their abundances are considered.
FirstlyFicus spare able to dominate a plot’s woodland
canopywith few species. This was seeninthe fieldto be
greater withFicus naudicum, where a single specimen
could account for 50% of the overallcover. Conversely
Euphorbia provedto have a muchmore diminished
influence onthe general woodlandcanopy. It’s less
expansive coverage coupledwith its comparatively
stunted height, means it onlydominates the canopyif
nothing else is able to outcompete. This is true for plot
X6 where the rockyterrainplays to Euphorbia’s abilityto
grow in the shallowest of soils, withstatistical evidence
given inthe significant positive relationship(Fs 39.3, DoF
1.1 and P<1%) betweenexposedrock and percentage
cover of Euphorbia. There is further evidence to suggest
that while the dominance of Ficus sp. oftenrelated to a
lack of cover inthe lower two canopylayers (with
circular patches of bare earth often directlybelowFicus
trunks) the presence of Euphorbiainhighabundances
was oftencoupledwitha greater speciesrichness and
abundance at the understoreylayer. Nevertheless, it
cannot be statisticallyproven that this is due to the
presence of Euphorbia, but it wouldbe a
commonsensical notionto suggest that the small canopy
woulddiminishlight as a limiting factor, allowing shade
intolerant species (of which there are more present on
the island)to establishor prevailagainst shade tolerant
species(namelyNephrolepis).
Pisonia grandis effects onwoodland structure is the
most dramatic of allthe tree species, due to both its
indisputable prominence andits propagative traits.
Previous studiesof the permanent plots have focused
on the tree height of the four lead treeswith little
consideration of the middle canopy(0.5m – 2.5m), yet
this middle sectioninwhich Pisonia is soactive,
determines future tree dominance andalsoacts as a
crucial habitat niche for the manynesting birds. Its
abilityto grow from fallen adults allows it to
immediatelyoutcompete other trees for the newly
available space, but it also provides a platform, which is
raised above the understorey, whichagaineliminates
competitionfrom herbaceous plants. It is throughthis
abilitythat dense and structurallycomplex middle-
canopiesarise, whichare observablybeneficial for tree
nesting species (and are thus incremental to the high
populations of Aride’s lesser noddies and fairyterns).
10. In terms ofthe herbaceous understoreylayer (<0.5m),
Rothmaniaannae appears to have a recorded
relationship(see both table 3.1 and3.3) withglade
environments or more preciselyAsystasia;anindicator
speciesfor glade environments. Of the 7 sites that
Asystasia gangetica was present, Rothmaniadominated
the upper canopyin 4 sites:K5, N4, M5, X7 and was
present inall but plot NEW 3. In relationto canopy
structure Rothmania createsa wide apparentlydense
canopyof leaves, makingthe relationshipwith an
understoreyshade intolerant species unlikely.
Nevertheless, the relationship could, andthis is simply
hypothesising, be due to the shape, size and structure of
the leaves allowinglight to penetrate, especiallywhen
there is a breeze.
Tree Dynamics
The results for the tree dynamics reflect those of
Fursinger and Putallaz (2008) (see graph3.1), with
Pisonia having a muchgreater prominence value for
both adults and saplings thananyof the other species
recorded. The successof this species is not onlydue to
its efficient andfast propagation, but its abilityto
inhabit andremain competitive inenvironmentally
difficult conditions:salt spray, steepslopes, shallowsoils
and at times strong winds. The noticeablyhighPVs of
Rothmaniaannae saplings in comparison to adults
indicates that its population inthe recordedplots is able
to sustain itself, andlikelyincrease inthe future due to
its general longevity. The opposite canbe said for Ficus
nautarumwhichhasa greater PV for adults rather than
saplings. Its abilityto grow to a greater height then
surroundingspecies, create a dense canopyto inhibit
competition, extendan expansive stabilising root
system, anddistinct longevity does however indicate it
has the abilityto wait for future saplings to establish.
Both Euphorbia andFicus reflexa share similar PVs for
saplings andadults despite possessing different plant
traits inorder to establishin an area. As mentioned
previous Euphorbia hasthe abilityto colonise regions of
extensive bare rock without requiringa great depth of
soil inorder to root. Ficus reflexa however, like Ficus
nautarumis able to spreadits roots over the surface of
rocks in searchof pockets ofdeeper soil. Although
apposing methods of colonisationboth appear to be as
successful as the other withthe populations of the two
speciesable to sustainthemselves.
Report summary
Taking the 18 measuredplots to be a true
representation of Aride’s hillslope environment several
concluding remarks canbe made fromthis investigation:
Despite a considerable change indiversity index,
the frequencyof Asystasiagangetica has continued
to decrease, andthus indicatesa shrinking of the
more diverse glade environments.
Consequentiallyfurther measures should be made
to maintainandwhere possible establish newglade
areas, especiallywhere Pisonia is encroaching.
Rothmaniaannae, despite being able to dominate a
canopy, has anobservedandproven relationship
with glade environments.
Pisonia grandis remains the most prominent
speciesof tree onAride, occuring as either an adult
or saplinginall the surveyedplots withits high
populationcapable of sustainedgrowth. Pisonia’s
propagative abilityis alsoresponsible for the
creationof dense middlecanopies, whichoffer a
habitat niche for nestingbirds.
Ficus nautarumhas an agingpopulation, but its
plant traits will likelyinhibit anymajor decreases in
populationinthe long-term.
It can be noted that tree diversityis a requirement
within the hillside environment given eachspeciesoffers
differingattributes that affect a habitat:Ficus sp provide
intricate root systems offeringcover for the ground
nesting white-tailedtropic birds and bothburrowing
shearwater species, Pisonia grandisfor the dense
middle-section canopyfor tree nesting species, with
glade regions benefitingfrom Euphorbia’s and
Rothmania’s specific canopycovers.
11. References
Aride Island, Annual Report (1979). ICS Internal Document
(unpublished).
Betts. Aride Island Annual Report (1997). ICS Internal Document
(unpublished).
Carty and Carty. Aride Island Annual Report (2005). ICS Internal
Document (unpublished).
G. E Castle and R.Mileto. (1994). Flora of Aride Island. Seychelles. Eco
Tech.
F. Freidmann. (1986). Flowers and Trees of Seychelles. Editions
Delroisse.
Fursinger, D and Putallaz, O. (2008). Vegetation Monitoring Aride Island
(Seychelles). Geobatanical Institute,Zurich.
S. A. Robertson. (1984).Flowering Plants of Seychelles.Royal Botanic
Gardens.
B. Sampson and Sampson E. Aride Island Annual Report (1997). ICS
Internal Document (unpublished)