Diversity of poroid and some corticoid wood-inhabiting fungi along the rainfall gradient in tropical forests, Costa Rica

2001 ◽  
Vol 17 (3) ◽  
pp. 353-369 ◽  
Author(s):  
IRENE LINDBLAD

The influence of a rainfall gradient on the distribution and species richness of some groups of wood-inhabiting basidiomycetes was explored in Costa Rican tropical forests. The relationships between these fungi and wood size and decay stage were also studied. Basidiocarps of all poroid and some corticoid fungi were recorded in three plots of 30 logs in each of dry, moist, and wet forests. The logs were surveyed three times during one year, covering all seasons. The species richness gradient was inversely related to the rainfall gradient, with most species in the dry forest (51), least in the wet forest (37), and intermediate in the moist forest (44). A total of 102 species were identified. Only six species occurred at all three sites. Two of the four most common species were new to science. The composition of wood-inhabiting fungal species in the dry forest varied from both the moist and the wet forest, while species composition in the two latter forest types was difficult to distinguish. Both frequent and rare species utilized the different decay stages as expected from availability of substrate. Perennials and rare species tended to occur on large logs in the dry forest, while all species tended to occur on large logs in the moist forest, but not in the wet forest.

1992 ◽  
Vol 82 (1) ◽  
pp. 29-39 ◽  
Author(s):  
Tibebu Habtewold ◽  
Jan Landin

AbstractAdult grasshopper (Orthoptera: Acridoidea, Tetrigioidea Tettigonioidea) assemblages were sampled at four localities in south-eastern Shoa, around Debre Zeit, Ethiopia, between August 1986 and September 1988. Three localities were followed for the whole period but the fourth locality was followed only between August 1986 and July 1987. Samples were taken fortnightly from both black and light soil fields of tef and wheat crops, each in three replicates. The fauna consisted of twenty-nine taxa of both short- and longhorned grasshoppers, twenty-six of which are identified to species. Over 70% of the species belong to Acrididae and most of them are either pests or potential pests of cereal crops. Species richness, diversity and dominance within and between sites and seasons did not differ much during the two year period. The composition and structure of the assemblage was relatively constant. Despite fluctuation in abundance, dominant and common species remained common and rare species rare. Aiolopus longicornis Sjöstedt was most dominant. Some species are more abundant on black soil than on light soil and vice versa. The results are compared to grasshopper assemblages studied elsewhere.


2021 ◽  
Vol 288 (1948) ◽  
Author(s):  
Ke Cao ◽  
Richard Condit ◽  
Xiangcheng Mi ◽  
Lei Chen ◽  
Haibao Ren ◽  
...  

The decline in species richness at higher latitudes is among the most fundamental patterns in ecology. Whether changes in species composition across space (beta-diversity) contribute to this gradient of overall species richness (gamma-diversity) remains hotly debated. Previous studies that failed to resolve the issue suffered from a well-known tendency for small samples in areas with high gamma-diversity to have inflated measures of beta-diversity. Here, we provide a novel analytical test, using beta-diversity metrics that correct the gamma-diversity and sampling biases, to compare beta-diversity and species packing across a latitudinal gradient in tree species richness of 21 large forest plots along a large environmental gradient in East Asia. We demonstrate that after accounting for topography and correcting the gamma-diversity bias, tropical forests still have higher beta-diversity than temperate analogues. This suggests that beta-diversity contributes to the latitudinal species richness gradient as a component of gamma-diversity. Moreover, both niche specialization and niche marginality (a measure of niche spacing along an environmental gradient) also increase towards the equator, after controlling for the effect of topographical heterogeneity. This supports the joint importance of tighter species packing and larger niche space in tropical forests while also demonstrating the importance of local processes in controlling beta-diversity.


2018 ◽  
Vol 285 (1876) ◽  
pp. 20172878 ◽  
Author(s):  
Yuxin Chen ◽  
María Natalia Umaña ◽  
María Uriarte ◽  
Shixiao Yu

Why tropical forests harbour an exceptional number of species with striking differences in abundances remains an open question. We propose a theoretical framework to address this question in which rare species may have different extirpation risks depending on species ranks in tree growth and sensitivities to neighbourhood interactions. To evaluate the framework, we studied tree growth and its responses to neighbourhood dissimilarity (ND) in traits and phylogeny for 146 species in a neotropical forest. We found that tree growth was positively related to ND, and common species were more strongly affected by ND than rare species, which may help delay dominance of common species. Rare species grew more slowly at the community-wide average ND than common species. But rare species grew faster when common species tended to dominate locally, which may help reduce extirpation risk of rare species. Our study highlights that tree growth rank among species depends on their responses to neighbourhood interactions, which can be important in fostering diversity maintenance in tropical forests.


2019 ◽  
Vol 14 (4) ◽  
pp. 489-498
Author(s):  
Felipe Donateli Gatti ◽  
Marco Antonio Alves Carneiro

Species are elementary units in community ecology studies. However, sample limitations obstruct the elaboration of accurate faunistic inventories, especially in biodiversity hotspots, such as tropical forests. In this way, the objective of this research was to describe the richness, using different non-parametric estimators of richness, in the family Cerambycidade, a group of hyperdiverse insects in the Atlantic Forest. Five hundred and eighty-one specimens belonging to 145 species and 3 subfamilies were collected. Among the species sampled, 46.2% were considered singletons, 13.8% doubletons, 48.95% unicates, 15.15% duplicates and 90.3% ecologically rare. The species accumulation curves did not stabilize, which was already expected considering that more species and individuals were sampled in the last months of collection. The estimated richness presented values much higher than the observed richness. This was a reflect of the high proportion of ecologically rare species present in the sample. This work showed that faunistic inventories of hyperdiverse groups, with only one year of collection and a single sampling methodology may underestimate the species richness of a region. Thus, larger time series associated with different collection methods are essential for a more accurate survey of biodiversity in the Atlantic Forest.


2016 ◽  
Author(s):  
A. Tovo ◽  
S. Suweis ◽  
M. Formentin ◽  
M. Favretti ◽  
Jayanth R. Banavar ◽  
...  

The quantification of tropical tree biodiversity worldwide remains an open and challenging problem. In fact, more than two-fifths of the global tree population can be found either in tropical or sub-tropical forests1, but species identities are known only for ≈ 0.000067% of the individuals in all tropical forests2. For practical reasons, biodiversity is typically measured or monitored at fine spatial scales. However, important drivers of ecological change tend to act at large scales. Conservation issues, for example, apply to diversity at global, national or regional scales. Extrapolating species richness from the local to the global scale is not straightforward. Indeed, a vast number of different biodiversity estimators have been developed under different statistical sampling frameworks3–7, but most of them have been designed for local/regional-scale extrapolations, and they tend to be sensitive to the spatial distribution of trees8, sample coverage and sampling methods9. Here, we introduce an analytical framework that provides robust and accurate estimates of species richness and abundances in biodiversity-rich ecosystems, as confirmed by tests performed on various in silico-generated forests. The new framework quantifies the minimum percentage cover that should be sampled to achieve a given average confidence in the upscaled estimate of biodiversity. Our analysis of 15 empirical forest plots shows that previous methods10,11 have systematically overestimated the total number of species and leads to new estimates of hyper-rarity10 at the global scale11, known as Fisher’s paradox2. We show that hyper-rarity is a signature of critical-like behavior12 in tropical forests13–15, and it provides a buffer against mass extinctions16. When biotic factors or environmental conditions change, some of these rare species are more able than others to maintain the ecosystem’s functions, thus underscoring the importance of rare species.


2020 ◽  
Vol 25 (9) ◽  
pp. 1576-1588
Author(s):  
Jacek Kamczyc ◽  
Daniel Szemis ◽  
Cezary K. Urbanowski ◽  
Jacek Malica ◽  
Emilia Pers-kamczyc

The European beech (Fagus sylvatica L.) is a dominant tree species in European forests and it has a huge ecological significance and high economic value. Due to its large dimensions, it can produce large amounts of decayed wood (CWD) which may be critical for maintaining the population of many rare species including mites. Many studies focused on mite (Mesostigmata) abundance, species richness, or diversity in CWD, however, our knowledge on mite biomass is still scarce. Therefore, the main aim of that study was to recognize the Mesostigmata biomass in logs and adjacent soil. In total, 90 samples (125 cm3, 5 cm depth) were collected from European beech logs and soil with litter thickness. Soil samples were collected from ecotone zone (soil near the log) and further three distances—0.5 m, 1.0 m, 1.5 m away from the log. Body length and width were measured for each individual of rare species and in the case of common species at least for 10 individuals. Our study revealed the highest mite biomass in CWD and soil near to the log (ecotone). Total male biomass was the highest in CWD and differed significantly from all other soil microhabitats. Female biomass did not differ between soil and CWD, whereas deutonymphs biomass differed between CWD and soil 1.0 m away from the log. Mean abundance, species richness, and diversity did not differ between the microhabitats. Decaying logs were dominated by Janietella pulchella whereas soil by Veigaia nemorensis. In conclusion, decayed European beech logs maintain the highest male and deutonymph biomass when compared to adjacent soil. Beech logs are important microhabitats for Mesostigmata mite communities, where they reached the highest abundance. 


Entropy ◽  
2019 ◽  
Vol 21 (6) ◽  
pp. 616
Author(s):  
Michael G. Bowler ◽  
Colleen K. Kelly

Data on the seasonally dry tropical forests of Mexico have been examined in the light of statistical mechanics. The results suggest a division into two classes of species. There are drifting populations of a cosmopolitan class capable of existing in most dry forest sites; these have a statistical distribution previously only observed (globally) for populations of alien species. We infer that a high proportion of species found only at a single site are specialists, endemics, and that these prefer sites comparatively low in species richness.


2006 ◽  
Vol 38 (4) ◽  
pp. 373-382 ◽  
Author(s):  
Juri NASCIMBENE ◽  
Stefano MARTELLOS ◽  
Pier Luigi NIMIS

135 infrageneric taxa of epiphytic lichen were found in 20 stands of tree-line forests of the Central-Eastern Italian Alps. Three forest types were considered: (1) late successional stands with several large trees, (2) pioneer stands on abandoned pastures without large trees, and (3) open and grazed stands. They were compared on the basis of four main criteria: (1) species richness, (2) number of rare species, (3) number of species that are exclusive to the subalpine belt in Italy, and (4) number of species that are exclusive to the Alps in Italy. Species richness is higher in the late successional stands, which also host a higher share of rare and exclusive species. The total number of rare species per site is correlated with the total number of species, as well as with the number of common species, and with the total number of macrolichens. Rare macrolichens are correlated with common macrolichens. Two main groups of target species with decreasing conservation priority are identified. Letharia vulpina is suggested as signal species for sites worthy of conservation. The guild of macrolichens may be used as an indicator of both species richness and of the occurrence of rare species.


2008 ◽  
Vol 38 (5) ◽  
pp. 1033-1041 ◽  
Author(s):  
Fred L. Bunnell ◽  
Toby Spribille ◽  
Isabelle Houde ◽  
Trevor Goward ◽  
Curtis Björk

Lichen communities of forests often appear to be negatively affected by timber harvest presumably because of reduction of suitable substrate and increased desiccation. We examined species richness and composition of lichens on wood of logs of the same decay class in unlogged stands (>140 years old) and logged, 20- to 30-year-old stands. There was no significant difference in species richness or mean lichen cover between logged and unlogged stands, but species composition differed, including species that were unique to either logged or unlogged stands. Crustose lichens accounted for 71% of rare species and all of the species occurring more commonly in unlogged stands; macrolichens accounted for 82% of common species and 60% of the species occurring more commonly in logged stands. Diameter at breast height and decay characteristics of down wood were the best predictors of lichen richness. Among lichen-rich, decay class 3 logs, relatively small amounts of retained down wood sustained lichen richness equivalent to unlogged stands. It appears important to ensure that decay classes favourable to lichens are retained after harvest.


Author(s):  
M. A. Gondal ◽  
S. Iqbal ◽  
U. Atique ◽  
N. U. Saher ◽  
N. A. Qureshi ◽  
...  

Abstract The primary objective of this study was to investigate the seasonal fish and crustacean variations concerning taxonomic composition, species richness, and diversity in sandy beach habitat. For this purpose, we investigated the Sonmiani Hor lagoon area during four distinct seasons, i.e., northeast (NE) monsoon, pre-monsoon, south-west (SW) monsoon, and post-monsoon for one year. During each haul, the net was pulled about 100m along the beach in 0.5m depth. The results showed a strong linear correlation between the diversity index and equitability in fishes (r = 0.978). The diversity index was strong negatively correlated with the abundance and biomass (r = -0.978, -0.972, respectively). The physical attributes like sea surface water temperature and salinity showed a strong negative effect on species assemblages (r = -0.981 and -0.943, respectively). The mean air and water temperature illustrated approximately 3°C difference during NE and pre-monsoon seasons. However, salinity, pH, and electrical conductivity did not show any significant seasonal variabilities. Under the ecological indices, the fish species displayed higher diversity (H’ = 3.19) during SW monsoon, whereas the lowest diversity was observed during pre-monsoon (H’ = 1.58). The equitability and species richness, however, remained more noticeable during SW monsoon (J’ = 0.81). The total number of individuals of fish and crustaceans reached 4799 with 3813 fish individuals and 986 individuals of crustaceans. A total of 27 families of fish while five crustacean families comprising of 30 genera and 38 fish species while ten genera and 17 species of crustaceans were recorded. Liza subviridis displayed the highest abundance among the sampled fish species. In conclusion, fish species constituted a significant part of the coastal fauna in the study area. The seasonal variations displayed distinct variations in fish species composition and diversity.


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