scholarly journals EFEITO DAS ATIVIDADES ANTRÓPICAS NA COBERTURA VEGETAL NA RESERVA FLORESTAL DE MECUBÚRI, MOÇAMBIQUE

Nativa ◽  
2021 ◽  
Vol 9 (5) ◽  
pp. 588-593
Author(s):  
Aguinaldo Joaquim Mário ◽  
Sailon Augusto Roia Mesa ◽  
Caetano Miguel Lemos Serrote

O estudo foi realizado na Reserva Florestal de Mecubúri, em Moçambiquee, visando avaliar os efeitos das atividades antrópicas sobre a cobertura florestal. Áreas de queimada, agrícola e de exploração florestal foram comparadas com uma área controle em termos de composição e fitossociologia. Em cada área, foram estabelecidas, de maneira sistemática, parcelas quadrangulares de 20 x 20 m, distantes 20 m uma da outra, sendo realizado o levantamento da vegetação adulta e da regeneração. Foram determinados índices de similaridade, diversidade e riqueza. Os resultados indicaram existir dissimilaridade entre as áreas, sendo que as espécies Julbernardia globiflora, Diplorhynchus condylocarpon, Brachystegia utilis, Millettia stuhlmannii, Afzelia quanzensis, Burkea africana e Cussonia arborea destacaram-se em termos de abundância, frequência, dominância, Índice de Valor de Importância (IVI) e regeneração. O maior número de árvores por hectare foi encontrado na área de controle e o menor número foi encontrado na área agrícola. Com base no índice de dispersão de Morisita, a maior parte das espécies distribui-se de forma aleatória e agrupada. A distribuição diamétrica das árvores seguiu o padrão de J-invertido, característico de florestas naturais.  As práticas de queimadas, agricultura e exploração florestal contribuem na redução da cobertura florestal na Reserva Florestal de Mecubúri. Palavras-chave: fitossociologia; conservação; desmatamento.   The effect of anthropic activities on forest coverage in the Mecubúri Forest Reserve, Mozambique   ABSTRACT: The study was carried out in the Mecubúri Forest Reserve, Mozambique, with the purpose of evaluating the effects of human activities on the forest cover. Burning, agricultural and logging areas were compared with a control area in terms of composition and phytosociology. In each area were systematically established 20 x 20 m quadrangular plots, 20 m apart from each other, in which were carried out the survey of adult vegetation and regeneration. The similarity, diversity and richness indices were determined. The results showed that there is dissimilarity between the areas and the species Julbernardia globiflora, Diplorhynchus condylocarpon, Brachystegia utilis, Millettia stuhlmannii, Afzelia quanzensis, Burkea africana e Cussonia arborea stood out in terms of abundance, frequency, dominance, Importance Value Index (IVI) and regeneration. The largest number of trees per hectare was found in the control area, and the smallest number was found in the agricultural area. Based on the Morisita dispersion index, most species have random and clustered distribution. The diametric structure of the trees followed the inverted-j, typical of natural forests. Burning, agriculture and logging contribute to the reduction of forest cover in the Mecubúri Forest Reserve. Keywords: phytosociology; conservation; deforestation.

2018 ◽  
Vol 4 (1) ◽  
pp. 1-12
Author(s):  
Sateesh Suthari ◽  
Vatsavaya S. Raju

Abstract It is important to understand the tree species composition, abundance, species diversity and stratification in tropical dry deciduous forests that are under threat. A quadrat study was attempted in the dry deciduous forests along the ecological gradients in the Godavari Valley of northern Telangana, India. The study records the presence of 110 flowering plant taxa belonging to 82 genera and 37 families in 120 sampled plots, and there was enumeration of 15,192 individuals of ≥10 cm girth at breast height. Tectona grandis (teak) is the principal forest cover component in the region, which often formed pure stands in Adilabad and, to some extent, in Nizamabad districts. Further down to the Warangal district, teak was gradually replaced by Terminalia alata. Twenty tree species were found dominant at one place to the other, and the top 10 dominant taxa have shared nearly 41% of the total density of the forest cover. The tree relative density ranged from 0.007% to 20.84%. The values of Importance Value Index were between 0.245 (12 spp. including some exotics) and 32.6 (teak). These baseline data help to know the change detection along the gradients in the tropical forest ecosystem of a major river valley in the region and the drivers of change


2016 ◽  
Vol 14 (1) ◽  
pp. 19 ◽  
Author(s):  
Andi Kusumo ◽  
Azis Nur Bambang ◽  
Munifatul Izzati

ABSTRAK Hutan Tesso Nilo merupakan kawasan dengan tingkat keanekaragaman tanaman berpembuluh dan merupakan habitat bagi satwa terancam punah yaitu harimau sumatera (Panthera tigris sumatrae) dan gajah sumatera (Elephas maximus sumatranus). Kawasan ini tidak luput dari kegiatan perambahan dan di konversi menjadi perkebunan dan permukiman. Pembukaan lahan hutan akan mengakibatkan rusaknya fungsi hutan dan mengakibatkan musnahnya berbagai jenis flora dan fauna. Tujuan penelitian ini adalah untuk mengetahui akibat yang ditimbulkan oleh perambahan hutan terhadap strukur vegetasi kawasan hutan. Metode yang digunakan adalah survei dengan menggunakan sampling vegetasi petak dalam jalur dilokasi hutan alam dan hutan terdegradasi akibat perambahan. Hasil dianalisis untuk mengetahui kelimpahan vegetasi, indeks nilai penting dan indeks keanekaragaman (Shannon-Wiener). Hasil penelitian menunjukkan bahwa perambahan hutan mengakibatkan terjadinya perubahan pada struktur vegetasi. Perambahan mengakibatkan penurunan jumlah kelimpahan vegetasi, nilai keanekaragaman, dan dominansi jenis (indeks nilai penting) baik pada tingkat semai, pancang, tiang dan pohon. Kata kunci: Taman Nasional Tesso Nilo, struktur vegetasi, perambahan ABSTRACT Tesso Nilo forest is an area with a greater diversity of vascular plants and habitat for an endangered species, namely the Sumatran tiger (Panthera tigris sumatrae) and the Sumatran elephant (Elephas maximus sumatranus). This area was not spared from encroachment and conversion to plantations and settlements. Forest clearing will cause damage to forest functions and lead to the extinction of various species of flora and fauna. The purpose of this study was to determine the consequences caused by the encroachment of the structure of forest vegetation. The method used was a survey by sampling vegetation plots in the path of the location of natural forests and forests degraded due to encroachment. The results were analyzed to determine the abundance of vegetation, an index of the importance and diversity index (Shannon-Wiener). The results showed that deforestation resulted in a change in the structure of vegetation. Encroachment degrades an abundance of vegetation, the value of diversity, and dominance type (Importance Value Index) is good for seedlings, saplings, poles and trees. Keywords:  Nasional Park of Tesso Nilo, vegetation structure Cara sitasi: Kusumo, A., Bambang, A. N., Izzati, M. (2016). Struktur Vegetasi Kawasan Hutan Alam dan Hutan Rerdegradasi di Taman Nasional Tesso Nilo. Jurnal Ilmu Lingkungan,14(1),19-26, doi:10.14710/jil.14.1.19-26


2017 ◽  
Vol 7 (2) ◽  
pp. 74-78
Author(s):  
MOHD HASMADI ISMAIL ◽  
PAKHRIAZAD HASSAN ZAKI ◽  
MOHD FADLI AHMAD FUAD ◽  
NOOR JANATUN NAIM JEMALI

Ismail MH, Fuad MFA, Zaki PH, Jemali NJN. 2017. Analysis of importance value index of unlogged and logged peat swamp forest in Nenasi Forest Reserve, Peninsular Malaysia. Bonorowo Wetlands 1: 74-78. Peat swamp forests are highly significant globally, both for their diverse and threatened species and as a representative of unique wetland ecosystems. Apart from its critical role in providing habitat for wildlife, the tropical peat swamp forest also acts as a gene bank that harbors potentially useful varieties of plant species. The composition of trees of the peat swamp forest in Nenasi Pahang State, Peninsular Malaysia were investigated especially in un-logged and logged over forests. The objectives of this study are two folds; (i) to identify and compare the dominant tree species in the two types of forests and (ii) to calculate the importance value index (IVI) of the vegetation in the study areas. Two plots of 50 m by 20 m were established in different forest type. At each site this quadrate was in turned subdivided using a 25 m by 20 m, and 5 m by 5 m, respectively. The results showed that the unlogged peat swamp forest is higher in tree species compared to logged peat swamp forest. There were 10 species distributed among 9 families in the unlogged forest and 7 species in 7 families in the logged forest. The most dominant species identified in unlogged peat swamp forest were Litsea sp., Syzygium sp. and Santiria laevigata. The IVI for these species were 71.21, 51.13 and 42.49. In logged peat swamp forest the dominant species are Shorea platycarpa, followed by Pometia pinnata, and Xylopia fusca. The IVI of these species were 87.38, 52.66 and 47.55, respectively. The study concludes that in the logged peat swamp forests about 40 percent of the tree composition has declined compared to unlogged peat swamp forest.


2021 ◽  
Vol 912 (1) ◽  
pp. 012082
Author(s):  
S H Sidabukke ◽  
T A Barus ◽  
B Utomo ◽  
Delvian ◽  
F R Aulin

Abstract Species association is a reciprocal relationship among species within a community and can estimate the community composition. This research aimed to obtain information regarding the level of dominance and plant species association in each forest land allocation. Data analysis tested in this study constituted an analysis of the importance value index and association analysis performed on the main constituent species with INP > 10% using a 2x2 Contingency Table. The research revealed that species association in understorey plants in plantation forests contained one pair with real associations, five with unreal associations, six with positive associations, and none with negative associations. Meanwhile, there were no real associations in protected forest areas, ten pairs with unreal associations, four pairs with positive associations, and six pairs with negative ones. There were two pairs with real associations in natural forests outside the company’s concessions, 13 species with unreal associations, four pairs with positive associations, and 11 pairs with negative associations.


Author(s):  
Alianis M. Orjuela Rojas ◽  
Carlos A. Villamil ◽  
Adolfo Sanjuan Muñoz

cover and structural attributes of mangrove forests in the Baja Guajira were estimated and identified. Forest cover was estimated from ASTER images and aerial photographs. The forest structure was evaluated along transects which were 10 m broad and as long as the width of the mangrove fringe. In each transect mangrove trees were identified and counted. The total height and the diameter at breast height (DBH) of the trees were measured and subsequently the basal area, density and Importance Value Index (IVI) calculated. The estimated mangrove cover of the Baja Guajira was 59.9 ha. The most frequent and dominant species was Laguncularia racemosa (0.54 m2.ha-1). Rhizophora mangle was present in 75 % of the stations, while Avicennia germinans was only found in the north of the study area. The highest average heights and diameters for R. mangle, L. racemosa and A. germinans were determined in Rincón Mosquito (12.9±2.3 m and 22.4±11.2 cm), Puerto Brisa (12.2±5.3 m and 20.8±9.8 cm) and La Enea (13.8± 4.3 m and 23.8±14.8 cm), sectors with a constant fresh water supply. The less developed forest, a monospecific forest of Conocarpus erectus, was observed in Dibulla station, with height and diameter averages of 2.8±0.6 m and 3.0±0.9 cm. In terms of natural regeneration, L. racemosa presented the highest proportion of seedlings in the study area, R. mangle was found in stations partly flooded and A. germinans had the highest density of seedlings and propagules at La Enea station.


2018 ◽  
Vol 47 (3) ◽  
pp. 351-360
Author(s):  
Ashfaque Ahmed ◽  
Md Ataullah ◽  
Parveen Rashid ◽  
Ashit Ranjan Paul ◽  
Sukumar Dutta ◽  
...  

The phytosociological analysis, species diversity and types, fidelity, presence, constancy, Sørensen similarity index and changes in forest cover, land and water areas since 1972 were analyzed. Forty six species were recorded both in quadrats and growing outside which belong to 26 families and 41 genera, 19 were distinguished as true mangrove species and the rest were mangrove associates. Leguminosae and Rhizophoraceae were the dominant families represented by 5 spp. each. Three species were found to be invasive, namely Blumea lacera (Burm. F.) DC., Catharanthus roseus (L.) G. Don., Wedelia chinensis (Osbeck) Merr. The maximum importance value index was found in Heritiera fomes Buch.-Ham (48.08). The overall species diversity (H) of SMF was found 3.81, species richness (d) was 9.10 and evenness (e) was 0.47. The forest area was 385,237 ha in 2015. The satellite images showed that the forest and water area of SMF decreased gradually till 2015 in comparison to 1972. The bare land of Sundarbans showed a significantly increasing trend till 2015 since 1972.


2020 ◽  
Vol 98 (2) ◽  
pp. 210-218
Author(s):  
Eduardo Alanís-Rodríguez ◽  
Laura Sánchez-Castillo ◽  
Cuauhtemoc Méndez-Osorio ◽  
Pamela Anabel Canizales Velázquez ◽  
Arturo Mora-Olivo ◽  
...  

Background: It is known that forest ecosystems have the capacity to regenerate over time. However, the anthropogenic influence over them arises the question on how different the original ecological conditions are after regeneration. Question: Do fires and agrochemicals have an influence on tree diversity in the study area? Studied species/ Data description/ Mathematical model: The structure and diversity data obtained from tree communities on four different areas were evaluated. The evaluated areas were a control area (mature forest without management) and three areas with different managements: reforested area, restored area and fumigated area. Study site and years of study: The study area was located in the Sierra de Guerrero, Mexico on areas affected by a fire that occurred in 2005. Seven years after the fire, in 2012, the investigation was performed. Methods: In each selected area a census of all tree species was carried out. The density, dominance, frequency, and importance value index were determined per species. Moreover, the diversity at community level and richness were estimated. Results: The control area showed highest values of density and dominance. The regenerated and reforested area showed highest values of specific richness and diversity. Conclusions: The evaluated areas showed significant differences when comparing diversity and structure indexes. It is recommended to implement reforestation actions in areas affected by forest fires.


2019 ◽  
Vol 9 (1) ◽  
pp. 44
Author(s):  
Irawaty Mertosono ◽  
Ratna Siahaan ◽  
Pience Maabuat

Struktur Makroalga Pada Ekosistem Lamun Di Kecamatan Tabukan Selatan, Kabupaten Kepulauan Sangihe, Sulawesi Utara(Structure of Macroalgae in Seagrass Ecosystems at South TabukanDistrict, Sangihe Islands Regency, North Sulawesi) Irawaty A. Mertosono1), Ratna Siahaan1*) Pience V. Maabuat1)1)Jurusan Biologi, Fakultas Matematika dan Ilmu Pengetahuan Alam, Universitas Sam Ratulangi, Manado 95115*Email korespondensi:[email protected] Diterima  15 Februari 2019, diterima untuk dipublikasi 28 Februari  2019 Abstrak Makroalga laut merupakan tumbuhan laut yang tidak memiliki akar, batang, maupun daun sejati. Kegiatan manusia berupa pemanfaatan makroalga, konversi lahan, dan transportasi laut dapat menjadi penyebab penurunan biodiversitas makroalga. Tujuan penelitian ini adalah untuk menganalisis struktur dan distribusi makroalga pada ekosistem lamun di Kecamatan Tabukan Selatan, Kabupaten Kepulauan Sangihe, Sulawesi Utara. Lokasi penelitian di tiga stasiun penelitian yaitu Pantai Karurung - Desa Salurang, Pantai Palareng - Desa Palareng dan Pantai Galoghong – Desa Batuwingkung. Penelitian dilakukan pada November-Desember 2018 dengan pengambilan sampel menggunakan metode garis transek (line transect) dengan teknik pencuplikan kuadrat. Makroalga yang ditemukan sebanyak 36 spesies yang terdiri atas 25 spesies Divisi Chlorophyta, sembilan (9) spesies Divisi Rhodophyta dan dua (2) spesies Divisi Phaeophyta. Makroalga Bornetella nitida memiliki Indeks Nilai Penting 39, 24% mendominasi di lokasi penelitian. Keanekaragaman Shannon-Wiener (H’) spesies makroalga di Stasiun I (H’:3,02) tergolong tinggi sedangkan pada Stasiun II (H’:2,86)  dan Stasiun III (H’:2,63) tergolong sedang. Secara keseluruhan, keanekaragaman spesies makroalga di Kecamatan Tabukan Selatang tergolong tinggi (H’:3,00). Kata kunci:   struktur makroalga, Pantai Karurung, Pantai Palareng, Pantai Galoghong,Tabukan Selatan Abstract Marine macroalgae are marine plant-like organisms that has no true roots, stems, or leaves. The human ativities of macroalgae utilization, land conversion, and sea transportation can cause of macroalgae biodiversity decline. The purpose of this study was to analyze the structure and distribution of macroalgae in seagrass ecosystems at South Tabukan District, Sangihe Islands Regency, North Sulawesi. The research locations were at three research stations, i.e. Karurung Beach - Salurang Village, Palareng Beach - Palareng Village and Galoghong Beach - Batuwingkung Village. The study was conducted in November-December 2018 with line transect method sampling and quadrate sampling technique. Macroalgae were 36 species consists of 25 species of Chlorophyta Division, nine (9) species of Rhodophyta Division and two (2) species of Phaeophyta Division. Macroalga Bornetella nitida had Importance Value Index 39.24% that dominated research locations. The Shannon-Wiener biodiversity Index (H’) of macroalgae species at Station I (H': 3.02) was classified as high while Station II (H': 2.86) and Station III (H ': 2.63) were moderate. Overall, macroalgae species diversity at Tabukan Selatang District was high (H’: 3.00). Keywords: Macroalgae structure, Macroalgae distribution, Karurung Beach, Palareng Beach, Galoghong Beach, South Tabukan


2021 ◽  
Vol 13 (3) ◽  
pp. 458
Author(s):  
Sol Milne ◽  
Julien G. A. Martin ◽  
Glen Reynolds ◽  
Charles S. Vairappan ◽  
Eleanor M. Slade ◽  
...  

Logging and conversion of tropical forests in Southeast Asia have resulted in the expansion of landscapes containing a mosaic of habitats that may vary in their ability to sustain local biodiversity. However, the complexity of these landscapes makes it difficult to assess abundance and distribution of some species using ground-based surveys alone. Here, we deployed a combination of ground-transects and aerial surveys to determine drivers of the critically endangered Bornean Orangutan (Pongo pygmaeus morio) distribution across a large multiple-use landscape in Sabah, Malaysian Borneo. Ground-transects and aerial surveys using drones were conducted for orangutan nests and hemi-epiphytic strangler fig trees (Ficus spp.) (an important food resource) in 48 survey areas across 76 km2, within a study landscape of 261 km2. Orangutan nest count data were fitted to models accounting for variation in land use, above-ground carbon density (ACD, a surrogate for forest quality), strangler fig density, and elevation (between 117 and 675 m). Orangutan nest counts were significantly higher in all land uses possessing natural forest cover, regardless of degradation status, than in monoculture plantations. Within these natural forests, nest counts increased with higher ACD and strangler fig density, but not with elevation. In logged forest (ACD 14–150 Mg ha−1), strangler fig density had a significant, positive relationship with orangutan nest counts, but this relationship disappeared in a forest with higher carbon content (ACD 150–209 Mg ha−1). Based on an area-to-area comparison, orangutan nest counts from ground transects were higher than from counts derived from aerial surveys, but this did not constitute a statistically significant difference. Although the difference in nest counts was not significantly different, this analysis indicates that both methods under-sample the total number of nests present within a given area. Aerial surveys are, therefore, a useful method for assessing the orangutan habitat use over large areas. However, the under-estimation of nest counts by both methods suggests that a small number of ground surveys should be retained in future surveys using this technique, particularly in areas with dense understory vegetation. This study shows that even highly degraded forests may be a suitable orangutan habitat as long as strangler fig trees remain intact after areas of forest are logged. Enrichment planting of strangler figs may, therefore, be a valuable tool for orangutan conservation in these landscapes.


Land ◽  
2021 ◽  
Vol 10 (5) ◽  
pp. 470
Author(s):  
Koichi Takenaka ◽  
Kenta Ikazaki ◽  
Saïdou Simporé ◽  
François Kaboré ◽  
Natacha Thiombiano ◽  
...  

Farmed parklands of the Central Plateau, Burkina Faso, integrate native woody vegetation with managed cropland. However, sapling survival in the parklands is increasingly threatened. This study characterized woody vegetation abundance along a 2.7 km long transect in the Doulou Basin, Boulkiemdé Province, Central West Region, to assess changes in vegetation composition since 1984. In addition, a householder survey was conducted to gain insight into tree uses and preferences and residents’ knowledge of regulations. In total, 4999 individuals from 26 tree species were recorded, including 123 individuals (11 species) with stem DBH ≥ 5 cm, and 4876 individuals (21 species) with stem DBH < 5 cm. The three species with the highest importance value index provided fruit for sale or self-consumption. Tree abundance was associated with soil type and topography; highest abundance was on Lixisol soils along the lower transect. Soil degradation and preference changes among residents since 1984 may have influenced tree abundance. Certain beneficial species (e.g., Vitellaria paradoxa) have declined in abundance, and certain exotics (Azadirachta indica and Eucalyptus camaldulensis) have expanded in distribution. Respondents expressed strongest interest in three species, including V. paradoxa, that show high versatility. These results supported the recorded tree composition. The respondents generally understood forest conservation regulations. Dissemination of regreening technology and awareness promotion among residents is essential for sustainable tree use in farmed parklands.


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