scholarly journals Spectral Diversity Metrics for Detecting Oil Pollution Effects on Biodiversity in the Niger Delta

2019 ◽  
Vol 11 (22) ◽  
pp. 2662 ◽  
Author(s):  
Nkeiruka Onyia ◽  
Heiko Balzter ◽  
Juan Berrio

Biodiversity monitoring in the Niger delta has become pertinent in view of the incessant spillages from oil production activities and the socio-economic impact of these spillages on the inhabitants who depend on the resources for their livelihood. Conventional methods of post-impact assessments are expensive, time consuming, and cause damage to the environment, as they often require the removal of affected samples/specimens for laboratory analysis. Remote sensing offers the opportunity to track biodiversity changes from space while using the spectral variability hypothesis (SVH). The SVH proposes that the species diversity of a sampled area is linearly correlated with the variability of spectral reflectance of the area. Several authors have tested the SVH on various land cover types and spatial scales; however, the present study evaluated the validity of the SVH against the backdrop of oil pollution impact on biodiversity while using vascular plant species as surrogates. Species richness and diversity indices were computed from vegetation data collected from polluted and non-polluted transects. Spectral metrics that were derived from Sentinel 2 bands and broadband vegetation indices (BVIs) using various algorithms, including averages, spread, dimension reduction, and so on, were assessed for their ability to estimate vascular plants species richness and diversity. The results showed significant differences in vegetation characteristics of polluted and control transects (H = 76.05, p-value = <0.05 for abundance and H = 170.03, p-value < 0.05 for richness). Spectral diversity metrics correlated negatively with species data on polluted transects and positively on control transects. The metrics computed using Sentinel 2A bands and vegetation indices proved to be sensitive to changes in vegetation characteristics following oil pollution. The most robust relationship was observed between the metrics and indices on control transects, whereas the weakest relationships were observed on polluted transects. Index-wise, the Simpson’s diversity index regressed better with spectral metrics (R2 > 0.5), whereas the Chao-1 richness index regressed the least (R2 < 0.5). The strength of the relationship resulted in successfully estimating species richness and diversity values of investigated transects, thereby enhancing biodiversity monitoring over time and space.

2014 ◽  
Vol 11 (19) ◽  
pp. 5521-5537 ◽  
Author(s):  
B. Magnússon ◽  
S. H. Magnússon ◽  
E. Ólafsson ◽  
B. D. Sigurdsson

Abstract. Plant colonization and succession on the volcanic island of Surtsey, formed in 1963, have been closely followed. In 2013, a total of 69 vascular plant species had been discovered on the island; of these, 59 were present and 39 had established viable populations. Surtsey had more than twice the species of any of the comparable neighbouring islands, and all of their common species had established on Surtsey. The first colonizers were dispersed by sea, but, after 1985, bird dispersal became the principal pathway with the formation of a seagull colony on the island and consequent site amelioration. This allowed wind-dispersed species to establish after 1990. Since 2007, there has been a net loss of species on the island. A study of plant succession, soil formation and invertebrate communities in permanent plots on Surtsey and on two older neighbouring islands (plants and soil) has revealed that seabirds, through their transfer of nutrients from sea to land, are major drivers of development of these ecosystems. In the area impacted by seagulls, dense grassland swards have developed and plant cover, species richness, diversity, plant biomass and soil carbon become significantly higher than in low-impact areas, which remained relatively barren. A similar difference was found for the invertebrate fauna. After 2000, the vegetation of the oldest part of the seagull colony became increasingly dominated by long-lived, rhizomatous grasses (Festuca, Poa, Leymus) with a decline in species richness and diversity. Old grasslands of the neighbouring islands Elliđaey (puffin colony, high nutrient input) and Heimaey (no seabirds, low nutrient input) contrasted sharply. The puffin grassland of Elliđaey was very dense and species-poor. It was dominated by Festuca and Poa, and very similar to the seagull grassland developing on Surtsey. The Heimaey grassland was significantly higher in species richness and diversity, and had a more even cover of dominants (Festuca/Agrostis/Ranunculus). We forecast that, with continued erosion of Surtsey, loss of habitats and increasing impact from seabirds a lush, species-poor grassland will develop and persist, as on the old neighbouring islands.


2015 ◽  
Vol 85 (1) ◽  
pp. 61
Author(s):  
Corrado Battisti ◽  
Aldo Boano ◽  
Michele Cento ◽  
Amedeo Circosta ◽  
Sergio Muratore

Around a yearly cycle (August 2011 - July 2012), we studied the assemblages of waders (Aves Charadriiformes) occurring in a Mediterranean remnant wetland, obtaining a set of diversity metrics. Mean total abundance shows a complementary pattern when compared to species richness and diversity: the highest values of mean total abundance were observed in December-January, due to high dominance of only one very abundant and gregarious species (the lapwing Vanellus vanellus). On the contrary, in this period, species richness and diversity showed the lowest values. These last metrics were highest in values during the April-September period when a large number of species of conservation concern utilize muddy areas as trophic and stop-over sites, due to the seasonal water stress. The highest values in species turnover index were observed between December-January and February-March when passage migrants (high richness, low abundance) substitute the wintering species (low richness, high abundance). Our data highlight that, in Mediterranean remnant wetlands, strategies should be addressed to increase the muddy suitable areas in the April-September period in order to maximize species richness and diversity. In fact, in these months these habitats host pre- and post-breeding migrant waders of conservation concern.


2014 ◽  
Vol 11 (6) ◽  
pp. 9379-9420 ◽  
Author(s):  
B. Magnússon ◽  
S. H. Magnússon ◽  
E. Ólafsson ◽  
B. D. Sigurdsson

Abstract. Plant colonization and succession on Surtsey volcanic island, formed in 1963, have been closely followed. In 2013, a total of 69 vascular plant species had been discovered on the island; of these 59 were present and 39 had established viable populations. Surtsey had more than twice the species of any of the comparable neighbouring islands and all their common species had established on Surtsey. The first colonizers were dispersed by sea, but after 1985 bird-dispersal became the principal pathway with the formation of a seagull colony on the island and consequent site amelioration. This allowed wind-dispersed species to establish after 1990. Since 2007 there has been a net loss of species on the island. A study of plant succession, soil formation and invertebrate communities in permanent plots on Surtsey and on two older neighbouring islands (plants and soil) has revealed that seabirds, through their transfer of nutrients from sea to land, are major drivers of development of these ecosystems. In the area impacted by seagulls dense grassland swards have developed and plant cover, species richness, diversity, plant biomass and soil carbon become significantly higher than in low-impact areas, which remained relatively barren. A similar difference was found for the invertebrate fauna. After 2000, the vegetation of the oldest part of the seagull colony became increasingly dominated by long-lived, rhizomatous grasses (Festuca, Poa, Leymus) with a decline in species richness and diversity. Old grasslands of the neighbouring islands Elliðaey (puffin colony, high nutrient input) and Heimaey (no seabirds, low nutrient input) contrasted sharply. The puffin grassland of Elliðaey was very dense and species-poor. Dominated by Festuca and Poa, it it was very similar to the seagull grassland developing on Surtsey. The Heimaey grassland was significantly higher in species richness and diversity, and had a more even cover of dominants (Festuca/Agrostis/Ranunculus). We forecast that with continued erosion of Surtsey, loss of habitats and increasing impact from seabirds a lush, species poor grassland will develop and persist, as on the old neighbouring islands.


2019 ◽  
Vol 13 (2) ◽  
pp. 181
Author(s):  
Ardiatma Maulana ◽  
Priyono Suryanto ◽  
Widiyatno Widiyatno ◽  
Eny Faridah ◽  
Bambang Suwignyo

Indonesia memiliki luasan hutan hujan tropis terluas nomor tiga setelah Brazil dan Afrika. Namun, tingkat degradasi hutan yang tinggi di Indonesia menyebabkan negara ini menjadi salah satu penyumbang emisi gas rumah kaca terbesar di dunia. Salah satu penyebab turunnya luasan hutan tropis di Indonesia adalah praktek perladangan berpindah. Suksesi vegetasi pasca perladangan berpindah dapat memberikan layanan ekologis berupa peningkatan tutupan vegetasi dan perbaikan sifat tanah yang jarang sekali terekspose pada tingkat lanjut. Penelitian ini bertujuan untuk mengetahui dinamika suksesi vegetasi padalahan pasca perladangan berpindah tingkat lanjut. Penelitian dinamika suksesi vegetasi dilakukan dengan pengambilan sampel tanaman bawah, semai sapihan dan pohon di lahan pasca perladangan dengan tiga umur yang berbeda, yaitu bera muda (1 – 10 tahun), bera sedang (11 – 20 tahun), bera tua (> 20 tahun), dan hutan alam dengan menggunakan metode petak bersarang dengan plot yang ditempatkan secara sistematik. Analisis vegetasi dengan menggunakan Indeks Nilai Penting, Kelimpahan Jenis, Keragaman, dan Kemerataan. Analisis varian dengan uji lanjut DMRT digunakan jika hasil dari tiap index vegetasi berbeda signifikan antar umur perladangan. Adanya pola peningkatan serta perbedaan yang nyata (P < 0,05) antara kelimpahan dan keragaman jenis vegetasi penyusun lahan bera sedang dengan lahan bera tua pada tingkatan pohon kecuali vegetasi penyusun tanaman bawah. Nilai keragaman dan kelimpahan jenis tingkat pohon lahan bera tua tidak berbeda nyata dengan hutan alam namun memiliki komposisi yang berbeda.The Dynamics of Succession of Vegetation in the Post-Shifting Cultivation Area in Central KalimantanAbstractIndonesia’s forests is the third largest tropical forest after Brazil and Africa. However, the high rate of forest degradation in Indonesia led this country become one of the most largest contributor of greenhouse gas emissions in the world. One of the causes of the degradation of tropical forest in Indonesia is the shifting cultivation practice. The succession of vegetation after shifting cultivation practice can provide ecological services such as increasing vegetation cover and improving soil properties but takes too long to recover. This study aims to understand the dynamics of vegetation succession in the post-shifting cultivation advanced stage. This study was conducted using systematical nested sampling method to take sample of shurb and herbs, and trees, including, seedling and, sapling growth stage form three different stage of post-shifting cultivation land areas, ie young fallow (1 - 10 years), intermediate fallow (11 - 20 years), old fallow (> 20 years), and natural forest. The vegetation data were then analyzed using Important Value, Species Richness, Diversity and Evenness Indices. Analysis of variance with post-hoc test of DMRT assays was used if the results each vegetation indices differed significantly between stage of post-shifting cultivation land. The Species Richness and Diversity Index of shurb and herb, seedling, sapling, and tree have significantly increased (P < 0,05) except the herb and shrub communities. The Species richness and Diversity Index of tree stage of old fallow were not significantly different from natural forest but it was composed with different species.


2020 ◽  
Vol 7 (3) ◽  
pp. 191722 ◽  
Author(s):  
Christian von Hoermann ◽  
Sandra Weithmann ◽  
Markus Deißler ◽  
Manfred Ayasse ◽  
Sandra Steiger

Dung beetles provide crucial ecosystem services and serve as model organisms for various behavioural, ecological and evolutionary studies. However, dung beetles have received little attention as consumers of large cadavers. In this study, we trapped copronecrophagous dung beetles on above-ground exposed piglet cadavers in 61 forest plots distributed over three geographically distinct regions in Germany, Central Europe. We examined the effects of land use intensity, forest stand, soil characteristics, vascular plant diversity and climatic conditions on dung beetle abundance, species richness and diversity. In all three regions, dung beetles, represented mainly by the geotrupid species Anoplotrupes stercorosus and Trypocopris vernalis , were attracted to the cadavers. High beetle abundance was associated with higher mean ambient temperature. Furthermore, A. stercorosus and T. vernalis were more abundant in areas where soil contained higher proportions of fine sand. Additionally, an increased proportion of forest understorey vegetation and vascular plant diversity positively affected the species richness and diversity of dung beetles. Thus, even in warm dry monocultured forest stands exploited for timber, we found thriving dung beetle populations when a diverse understorey was present. Therefore, forestry practices that preserve the understorey can sustain stable dung beetle populations and ensure their important contribution to nutrient cycles.


2021 ◽  
Author(s):  
Kaja Rola ◽  
Vítězslav Plášek ◽  
Katarzyna Rożek ◽  
Szymon Zubek

Abstract Aim Overstorey tree species influence both soil properties and microclimate conditions in the forest floor, which in turn can induce changes in ground bryophyte communities. The aim of the study was to investigate the effect of tree species identity and the most important habitat factors influencing understorey bryophytes. Methods We assessed the effect of 14 tree species and related habitat parameters, including soil parameters, vascular plant presence and light intensity on bryophytes in monospecific plots covered by nearly fifty-year-old trees in the Siemianice Experimental Forest (Poland). Results The canopy tree species determined bryophyte species richness and cover. The strongest differences were observed between plots with deciduous and coniferous trees. Soils with a more acidic pH and lower content of macronutrients supported larger bryophyte coverage. We also found a positive correlations between vascular plants and availability of light as well as bryophyte species richness. Conclusion Tree species identity and differences in habitat conditions in the forest floor lead to changes of ground bryophyte richness, cover and species composition. Consequently, the changes in the dominant tree species in the stand may result in significant repercussions on ground bryophyte communities. We indicated that the introduction of alien tree species, i.e. Quercus rubra, has an adverse effect on bryophyte communities and suggested that the selection of tree species that contribute to the community consistent with the potential natural vegetation is highly beneficial for maintaining ground bryophyte biodiversity.


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