scholarly journals Patterns of speciation are similar across mountainous and lowland regions for a Neotropical plant radiation (Costaceae: Costus)

2020 ◽  
Author(s):  
Oscar M. Vargas ◽  
Brittany Goldston ◽  
Dena L. Grossenbacher ◽  
Kathleen M. Kay
Keyword(s):  
Species Richness ◽  
Life Forms ◽  
Geographic Isolation ◽  
Climatic Niche ◽  
Colonization History ◽  
Tropical Mountains ◽  
Topographic Features ◽  
Plant Life Forms ◽  
Diversity Gradient ◽  
High Species Richness

AbstractHigh species richness and endemism in tropical mountains are recognized as major contributors to the latitudinal diversity gradient. The processes underlying mountain speciation, however, are largely untested. The prevalence of steep ecogeographic gradients and the geographic isolation of populations by topographic features are predicted to promote speciation in mountains. We evaluate these processes in a species-rich Neotropical genus of understory herbs that range from the lowlands to montane forests and have higher species richness in topographically complex regions. We ask whether climatic niche divergence, geographic isolation, and pollination shifts differ between mountain-influenced and lowland Amazonian sister pairs inferred from a 756-gene phylogeny. Neotropical Costus ancestors diverged in Central America during a period of mountain formation in the last 3 My with later colonization of Amazonia. Although climatic divergence, geographic isolation, and pollination shifts are prevalent in general, these factors don’t differ between mountain-influenced and Amazonian sister pairs. Despite higher climatic niche and species diversity in the mountains, speciation modes in Costus appear similar across regions. Thus, greater species richness in tropical mountains may reflect differences in colonization history, diversification rates, or the prevalence of rapidly evolving plant life forms, rather than differences in speciation mode.

scholarly journals Shifts in Riparian Plant Life Forms Following Flow Regulation

Forests ◽  
2020 ◽  
Vol 11 (5) ◽  
pp. 518 ◽  
Author(s):  
María D. Bejarano ◽  
Judith Sarneel ◽  
Xiaolei Su ◽  
Alvaro Sordo-Ward
Keyword(s):  
Species Richness ◽  
Relative Abundance ◽  
Life Form ◽  
Woody Species ◽  
Life Forms ◽  
River Regulation ◽  
Flow Regulation ◽  
Plant Life Forms ◽  
Plant Life ◽  
Riparian Plant

Flow regulation affects bordering riparian plant communities worldwide, but how different plant life forms are affected by river regulation still needs further research. In northern Sweden, we selected 10 rivers ranging from free-flowing to low, moderately, and highly regulated ones. In 94 reaches across those rivers, we evaluated the relative abundance of woody and herbaceous (i.e., graminoids and forbs) life forms, their species richness, and their relative presence. We also explored which, and to what extent, hydrological variables drove species assembly within each life form. The relative abundance and species richness of each life form decreased across river categories with increasing levels of regulation. This was particularly apparent in herbaceous life forms, and the most drastic decreases were observed in all life forms in moderately or highly regulated reaches. Additionally, when river regulation increased, the relative presence of many species from all life forms decreased. Unlike woody species, only a few new herbaceous species appeared in regulated reaches. A canonical correspondence analyses (CCA) revealed that a wide range of hydrological variables explained the occurrence of woody species, while fewer variables explained variation in the graminoid and forb life forms. We conclude that flow regulation and its intensity result into clear shifts in the relative abundance of different life forms, as well as in changes of within-group species richness and composition. Consequently, the modification of certain flow attributes in flow regulation schemes, as well as the intensity of these modifications, may alter the ratio between herbaceous and woody species, ultimately impacting the functions and benefits derived from each life form.

scholarly journals Floristics and life-forms along a topographic gradient, central-western Ceará, Brazil

Rodriguésia ◽  
2011 ◽  
Vol 62 (2) ◽  
pp. 341-366 ◽  
Author(s):  
Francisca Soares de Araújo ◽  
Rafael Carvalho da Costa ◽  
Jacira Rabelo Lima ◽  
Sandra Freitas de Vasconcelos ◽  
Luciana Coe Girão ◽  
...  
Keyword(s):  
Species Richness ◽  
Deciduous Forest ◽  
Woody Species ◽  
Life Forms ◽  
Northeastern Brazil ◽  
Topographic Gradient ◽  
Plant Life Forms ◽  
Species Overlap ◽  
Semi Arid Region ◽  
Biological Spectrum

Abstract To test whether the flora is organized in discrete or continuous units along a topographic gradient, three physiognomies were assessed on different soil classes in a semi-arid region of northeastern Brazil: caatinga (xeric shrubland) at altitudes from 300 to 500 m, deciduous forest at altitudes from 500 to 700 m and carrasco (deciduous shrubland) at 700 m. In each physiognomy a species inventory was carried out, and plants were classified according to life- and growth-forms. Species richness was higher in the deciduous forest (250) than in the carrasco (136) and caatinga (137). The caatinga shared only a few species with the carrasco (6 species) and the deciduous forest (18 species). The highest species overlap was between the deciduous forest and the carrasco (62 species). One hundred and four species occurred only in the caatinga, 161 only in the deciduous forest and 59 only in the carrasco. Woody species predominated in physiognomies on sedimentary soils with latosol and arenosol: 124 species occurred in the deciduous forest and 68 in the carrasco. In the caatinga on crystalline basement relief with predominance of planosol, herbs showed the highest species richness (69). Comparing the biological spectrum of Brazilian plant life-forms, the caatinga stood out with higher proportion of therophytes and chamaephytes. Considering the flora of the three phytophysiognomies studied here, we can affirm that the caatinga is a discrete floristic unit.

scholarly journals Flora of community managed forests of Palpa district, western Nepal

2018 ◽  
Vol 30 ◽  
pp. 102-120
Author(s):  
Pratiksha Shrestha ◽  
Ram Prasad Chaudhary ◽  
Krishna Kumar Shrestha ◽  
Dharma Raj Dangol
Keyword(s):  
Species Richness ◽  
Life Forms ◽  
Flowering Plant ◽  
Floristic Diversity ◽  
Managed Forests ◽  
Community Forest ◽  
Managed Forest ◽  
Fuel Wood ◽  
Community Forests ◽  
High Species Richness

Floristic diversity is studied based on gender in two different management committee community forests (Barangdi-Kohal jointly managed community forest and Bansa-Gopal women managed community forest) of Palpa district, west Nepal. Square plot of 10m×10m size quadrat were laid for covering all forest areas and maintained minimum 40m distance between two quadrats. Altogether 68 plots (34 in each forest) were sampled. Both community forests had nearly same altitudinal range, aspect and slope but differed in different environmental variables and members of management committees. All the species present in quadrate and as well as outside the quadrate were recorded for analysis. There were 213 species of flowering plant belonging to 67 families and 182 genera. Barangdi-Kohal JM community forest had high species richness i.e. 176 species belonging to 64 families and 150 genera as compared to Bansa-Gopal WM community forest with 143 species belonging to 56 families and 129 genera. According to different life forms and family and genus wise jointly managed forest has high species richness than in women managed forest. Both community forest are banned for fodder, fuel wood and timber collection without permission of management comities. There is restriction of grazing in JM forest, whereas no restriction of grazing in WM forest.

Community characteristics of forest understory birds along an elevational gradient in the Horn of Africa: A multi-year baseline

The Condor ◽  
2021 ◽  
Author(s):  
Kyle D Kittelberger ◽  
Montague H C Neate-Clegg ◽  
Evan R Buechley ◽  
Çağan Hakkı Şekercioğlu
Keyword(s):  
Species Richness ◽  
Species Turnover ◽  
Survival Rates ◽  
Elevational Gradient ◽  
Forest Understory ◽  
Bird Abundance ◽  
Tropical Mountains ◽  
Demographic Rates ◽  
Understory Birds ◽  
Over Time

Abstract Tropical mountains are global hotspots for birdlife. However, there is a dearth of baseline avifaunal data along elevational gradients, particularly in Africa, limiting our ability to observe and assess changes over time in tropical montane avian communities. In this study, we undertook a multi-year assessment of understory birds along a 1,750 m elevational gradient (1,430–3,186 m) in an Afrotropical moist evergreen montane forest within Ethiopia’s Bale Mountains. Analyzing 6 years of systematic bird-banding data from 5 sites, we describe the patterns of species richness, abundance, community composition, and demographic rates over space and time. We found bimodal patterns in observed and estimated species richness across the elevational gradient (peaking at 1,430 and 2,388 m), although no sites reached asymptotic species richness throughout the study. Species turnover was high across the gradient, though forested sites at mid-elevations resembled each other in species composition. We found significant variation across sites in bird abundance in some of the dietary and habitat guilds. However, we did not find any significant trends in species richness or guild abundances over time. For the majority of analyzed species, capture rates did not change over time and there were no changes in species’ mean elevations. Population growth rates, recruitment rates, and apparent survival rates averaged 1.02, 0.52, and 0.51 respectively, and there were no elevational patterns in demographic rates. This study establishes a multi-year baseline for Afrotropical birds along an elevational gradient in an under-studied international biodiversity hotspot. These data will be critical in assessing the long-term responses of tropical montane birdlife to climate change and habitat degradation.

scholarly journals Testing the potential of pollen assemblages to capture composition, diversity and ecological gradients of surrounding vegetation in two biogeographical regions of southeastern Europe

2021 ◽  
Author(s):  
Maria Papadopoulou ◽  
Ioannis Tsiripidis ◽  
Sampson Panajiotidis ◽  
Georgios Fotiadis ◽  
Daniel Veres ◽  
...  
Keyword(s):  
Vegetation Structure ◽  
Diversity Indices ◽  
Life Forms ◽  
Ecological Gradients ◽  
Vegetation Diversity ◽  
North Central ◽  
Plant Life Forms ◽  
Pollen Diagrams ◽  
Biogeographical Regions ◽  
Species Specific

AbstractDue to the complex relationship between pollen and vegetation, it is not yet clear how pollen diagrams may be interpreted with respect to changes in floristic diversity and only a few studies have hitherto investigated this problem. We compare pollen assemblages from moss samples in two southeastern European forests with the surrounding vegetation to investigate (a) their compositional similarity, (b) the association between their diversity characteristics in both terms of richness and evenness, and (c) the correspondence of the main ecological gradients that can be revealed by them. Two biogeographical regions with different vegetation characteristics, the Pieria mountains (north central Greece) and the slopes of Ciomadul volcano (eastern Romania), were chosen as divergent examples of floristic regions, vegetation structure and landscape openness. Pollen assemblages are efficient in capturing the presence or absence, rather than the abundance in distribution of plants in the surrounding area and this bias increases along with landscape openness and vegetation diversity, which is higher in the Pieria mountains. Pollen assemblages and vegetation correlate better in terms of richness, that is, low order diversity indices. Relatively high correlation, in terms of evenness, could be potentially found in homogenous and species poor ecosystems as for Ciomadul. Composition and diversity of woody, rather than herb, vegetation is better reflected in pollen assemblages of both areas, especially for Pieria where a direct comparison of the two components was feasible, although this depends on the species-specific pollen production and dispersal, the openness of landscape and the overall diversity of vegetation. Gradients revealed by pollen assemblages are highly and significantly correlated with those existing in vegetation. Pollen assemblages may represent the vegetation well in terms of composition, diversity (mainly richness) and ecological gradients, but this potential depends on land use, vegetation structure, biogeographical factors and plant life forms.

Distribution of plant life forms along an altitudinal gradient in the semi-arid valley of Zapotitlán, Mexico

2000 ◽  
Vol 11 (1) ◽  
pp. 39-42 ◽  
Author(s):  
Numa P. Pavón ◽  
Humberto Hernández-Trejo ◽  
Víctor Rico-Gray
Keyword(s):  
Altitudinal Gradient ◽  
Life Forms ◽  
Plant Life Forms ◽  
Plant Life ◽  
Semi Arid

scholarly journals Biodiversity hanging by a thread: the importance of fungal litter-trapping systems in tropical rainforests

2011 ◽  
Vol 8 (3) ◽  
pp. 397-400 ◽  
Author(s):  
Jake L. Snaddon ◽  
Edgar C. Turner ◽  
Tom M. Fayle ◽  
Chey V. Khen ◽  
Paul Eggleton ◽  
...  
Keyword(s):  
Species Richness ◽  
Leaf Litter ◽  
Plant Diversity ◽  
Habitat Complexity ◽  
Tropical Rainforests ◽  
Dramatic Reduction ◽  
Experimental Removal ◽  
Crucial Component ◽  
High Species Richness ◽  
Vital Resource

The exceptionally high species richness of arthropods in tropical rainforests hinges on the complexity of the forest itself: that is, on features such as the high plant diversity, the layered nature of the canopy and the abundance and the diversity of epiphytes and litter. We here report on one important, but almost completely neglected, piece of this complex jigsaw—the intricate network of rhizomorph-forming fungi that ramify through the vegetation of the lower canopy and intercept falling leaf litter. We show that this litter-trapping network is abundant and intercepts substantial amounts of litter (257.3 kg ha −1 ): this exceeds the amount of material recorded in any other rainforest litter-trapping system. Experimental removal of this fungal network resulted in a dramatic reduction in both the abundance (decreased by 70.2 ± 4.1%) and morphospecies richness (decreased by 57.4 ± 5.1%) of arthropods. Since the lower canopy levels can contain the highest densities of arthropods, the proportion of the rainforest fauna dependent on the fungal networks is likely to be substantial. Fungal litter-trapping systems are therefore a crucial component of habitat complexity, providing a vital resource that contributes significantly to rainforest biodiversity.

Seasonality in a taxocoenosis of molluscs from soft bottoms in the Bay of Cádiz (southern Spain)

2001 ◽  
Vol 81 (6) ◽  
pp. 903-912 ◽  
Author(s):  
Jose L. Rueda ◽  
Manuel Fernández-Casado ◽  
Carmen Salas ◽  
Serge Gofas
Keyword(s):  
Species Richness ◽  
Correspondence Analysis ◽  
Dominant Species ◽  
Southern Spain ◽  
Soft Bottom ◽  
Soft Bottoms ◽  
High Species Richness ◽  
Bay Of Cadiz ◽  
Bay Of Cádiz ◽  
Autumn And Winter

The macrofauna of molluscs associated with soft bottoms in the Bay of Cádiz (southern Spain) was studied monthly from February 1994 to January 1996. The number of species (63) is high for a soft bottom and is related to environmental characteristics (growth of macrophytes) and the biogeographical setting of the studied area. Corbula gibba (∼90%) was the dominant species in this taxocoenosis together with the gastropod Nassarius pygmaeus and the bivalves Pandora inaequivalvis, Parvicardium exiguum and Macoma melo. The most frequent species during the two years was also the bivalve Corbula gibba (100%) followed by the gastropods Nassarius pygmaeus, Tricolia tenuis, Rissoa membranacea and the bivalve Macoma melo. Total abundance of the taxocoenosis in both years reached higher values in spring. The dynamics of the ecological indices such as diversity or evenness, and the species richness showed a similar pattern in both years, with low values of diversity and evenness together with high species richness in spring and summer months and the reverse in autumn and winter. The qualitative correspondence analysis of monthly samples shows an ordination related to seasonality in both studied years, however the values of Jaccard's coefficient do not indicate significant boundaries among the monthly samples. The quantitative correspondence analysis shows an ordination and grouping of samples related to the biology of species, particularly with the recruitment of C. gibba, the dominant species. The existence of similar trends in the structure of the taxocoenoses over both years, and the seasonality highlighted by the qualitative correspondence analysis, seems to indicate a certain stability of the ecosystem.

Marshland vegetation of the class Phragmito-Magnocaricetea in northwest Croatia (Krapina river valley)

Biologia ◽  
2010 ◽  
Vol 65 (1) ◽  
Author(s):  
Zvjezdana Stančić
Keyword(s):  
Plant Cover ◽  
Ecological Factors ◽  
Nutrient Content ◽  
Field Work ◽  
Life Forms ◽  
River Valley ◽  
Soil Reaction ◽  
Alien Plant ◽  
Invasive Alien Plant ◽  
Plant Life Forms

AbstractMarshland vegetation of the class Phragmito-Magnocaricetea in the Krapina river valley was investigated during 2006 and 2007, and some sporadic investigations were made earlier. Phytosociological studies were carried out in accordance with the standard Braun-Blanquet methodology. As a result of the field work, and a small amount of data from the literature, 120 relevés were collected and 18 communities were established. For the purposes of comparison, the relevés were also classified using numerical methods. The clusters obtained mostly correspond to specific associations, but do not confirm the division into traditional vegetation alliances and orders. In the analysis of the ecological factors it is established that separation of the relevés is influenced by nutrient content, soil reaction, soil moisture, depth of water, and type of management. Analysis of the plant life forms shows, in all marshland communities, a prevalence of hemicryptophytes, geophytes and hydrophytes. The most widespread marshland communities of the investigated area are: Phalaridetum arundinaceae, Phragmitetum australis and Galio palustris-Caricetum ripariae. Furthermore, Carex randalpina community is recorded for the first time in Croatia. The most threatened marshland communities could be considered to be: Carex randalpina community, Caricetum vesicariae, Leersietum oryzoidis and Oenantho-Rorippetum. They are selected because of their very small surfaces in the investigated area and the small number of known localities within the territory of Croatia. The most invasive alien plant species in the Krapina river valley is Solidago gigantea. It spreads in potential habitats of marshland vegetation, and it is recorded in the species composition of many marshland communities. For the preservation of marshland vegetation, and especially threatened types, it is necessary to maintain the water regime of the habitats, to not remove natural plant cover due to spreading of neophytes, and to provide occasional mowing and burning.

Large herbivores suppress liana infestation in an African savanna

2021 ◽  
Vol 118 (41) ◽  
pp. e2101676118
Author(s):  
Tyler C. Coverdale ◽  
Ryan D. O’Connell ◽  
Matthew C. Hutchinson ◽  
Amanda Savagian ◽  
Tyler R. Kartzinel ◽  
...  
Keyword(s):  
Stable State ◽  
Life Forms ◽  
Tree Canopy ◽  
Alternative Stable State ◽  
African Savanna ◽  
Large Herbivore ◽  
Large Herbivores ◽  
Woody Vines ◽  
Plant Life Forms ◽  
Canopy Area

African savannas are the last stronghold of diverse large-mammal communities, and a major focus of savanna ecology is to understand how these animals affect the relative abundance of trees and grasses. However, savannas support diverse plant life-forms, and human-induced changes in large-herbivore assemblages—declining wildlife populations and their displacement by livestock—may cause unexpected shifts in plant community composition. We investigated how herbivory affects the prevalence of lianas (woody vines) and their impact on trees in an East African savanna. Although scarce (<2% of tree canopy area) and defended by toxic latex, the dominant liana, Cynanchum viminale (Apocynaceae), was eaten by 15 wild large-herbivore species and was consumed in bulk by native browsers during experimental cafeteria trials. In contrast, domesticated ungulates rarely ate lianas. When we experimentally excluded all large herbivores for periods of 8 to 17 y (simulating extirpation), liana abundance increased dramatically, with up to 75% of trees infested. Piecewise exclusion of different-sized herbivores revealed functional complementarity among size classes in suppressing lianas. Liana infestation reduced tree growth and reproduction, but herbivores quickly cleared lianas from trees after the removal of 18-y-old exclosure fences (simulating rewilding). A simple model of liana contagion showed that, without herbivores, the long-term equilibrium could be either endemic (liana–tree coexistence) or an all-liana alternative stable state. We conclude that ongoing declines of wild large-herbivore populations will disrupt the structure and functioning of many African savannas in ways that have received little attention and that may not be mitigated by replacing wildlife with livestock.

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