scholarly journals Vascular Epiphytic Diversity in a Neotropical Transition Zone Is Driven by Environmental and Structural Heterogeneity

2019 ◽  
Vol 12 ◽  
pp. 194008291988220 ◽  
Author(s):  
Edilia de la Rosa-Manzano ◽  
Glenda Mendieta-Leiva ◽  
Antonio Guerra-Pérez ◽  
Karla María Aguilar-Dorantes ◽  
Leonardo Uriel Arellano-Méndez ◽  
...  

Vascular epiphytes contribute significantly to tropical diversity. Research on the factors that determine vascular epiphytic diversity and composition in tropical areas is flourishing. However, these factors are entirely unknown in tropical-temperate transition zones, which represent the distribution limit of several epiphytic species. We assessed the degree to which climatic and structural variables determine the diversity of vascular epiphytic assemblages (VEAs) in a transition zone in Mexico: the El Cielo Biosphere Reserve. We found 12,103 epiphytic individuals belonging to 30 species and 15 genera along a climatic gradient from 300 to 2,000 m a.s.l. Bromeliaceae and Orchidaceae were the most species-rich families. Forests along the windward slope of the Sierra Madre Oriental (semideciduous forest and tropical montane cloud forest) had higher species richness than forests along the leeward slope (pine-oak forest and submontane scrub). Species richness was largely determined by seasonality and, to a lesser degree, by forest structure, whereas abundance was mainly determined by host tree size. Variation in VEAs composition was largely explained by climatic variables, whereas forest structure was not as important. VEAs differed among forest types and slopes in terms of taxonomic and functional composition. For example, certain bromeliad indicator species reflected differences between slopes. Although within-tree epiphytic species richness (alpha diversity) was low in this transition zone relative to other habitats, species turnover among forest types (beta diversity) was high. These findings suggest that each forest type makes a unique and important contribution to epiphytic diversity in this transition zone.

2014 ◽  
Vol 30 (5) ◽  
pp. 419-434 ◽  
Author(s):  
Tijl Essens ◽  
Euridice Leyequién ◽  
Carmen Pozo ◽  
Henricus F. M. Vester ◽  
Hector A. Hernández-Arana

Abstract:Understanding patterns in plant and herbivorous insect diversity across spatial and temporal scales is fundamental to ecology, but comparative multi-taxonomic studies in tropical seasonally dry forests remain scarce. In 36 sites, distributed over three forest age classes (5–10 y, 10–30 y, >100 y) and three seasonal forest types (dry, intermediate, humid), we sampled plants of different stem diameter classes while caterpillars were sampled across vertically distributed forest layers during three seasons over the year. We recorded 299 plant species and 485 caterpillar morphospecies. For large woody plants, species numbers showed a gradually increasing trend with forest age in the intermediate and humid forest types, while the main portion of explained variation in overall species turnover was accounted for by the forest type × forest age interaction (21.3–23.1% of 44.4–48.7%). Ordinations and multivariate pairwise comparisons suggested a faster but also very distinct successional development of species diversity of large plants in the driest compared with humid and intermediate forest types. In contrast, highest species numbers of small plants in the undergrowth was often found in the 5–10 y-old vegetation across forest types, whereas forest type was the major factor in overall species turnover (contributing 24.2% of 48.7% explained variation). Caterpillar species turnover was most correlated to species turnover of small plants; however, variation in caterpillar species diversity appears to be mostly regulated by seasonal cues, and to a lesser extent by patterns of regional turnover and local diversity of undergrowth plant species.


Botany ◽  
2017 ◽  
Vol 95 (6) ◽  
pp. 599-610 ◽  
Author(s):  
Edilia de la Rosa-Manzano ◽  
Antonio Guerra-Pérez ◽  
Glenda Mendieta-Leiva ◽  
Arturo Mora-Olivo ◽  
José Guadalupe Martínez-Ávalos ◽  
...  

We assessed the diversity, vertical distribution, and the effect of structural and geographical factors on the diversity of vascular epiphyte assemblages (VEAs) in two forest types in the “El Cielo” Biosphere Reserve. We found 2839 epiphyte individuals from 15 species on 240 host trees (27 species) in the semideciduous forest and 5085 individuals from 8 species on 215 host trees (12 species) in the pine–oak forest. Epiphytes showed a preference for the middle zone of the host trees. The diversity of VEAs was uneven in both forest types, although the VEA in the semideciduous forest was the most diverse. VEAs across forests were slightly similar in their composition (30% mean overlap), but very different in their structure (i.e., they did not share very abundant species). The variation in species richness among VEAs was influenced by forest structure, independently of forest type. Compositional differences of VEAs among forest types were explained by geographic distance and host-tree identity (31% and 28% variation explained, respectively). By characterizing the diversity of VEAs we provide a basic understanding of the factors influencing epiphyte diversity in these understudied ecosystems.


ISRN Forestry ◽  
2013 ◽  
Vol 2013 ◽  
pp. 1-11 ◽  
Author(s):  
Patrick Addo-Fordjour ◽  
Philip El Duah ◽  
David Kafui Kudjo Agbesi

The study was conducted to determine the factors that influenced liana species richness and structure in forests of different disturbance intensities (high, moderate, and low disturbance forests) in the Southern Scarp Forest Reserve, Ghana. Within each forest, lianas (dbh  cm) were enumerated in six  m2 plots located along transects. Soil physicochemical properties and forest structure were determined within the plots. Liana species richness and abundance were significantly lower in the high disturbance forest () whereas basal area was significantly higher in the low disturbance forest (). Tree abundance and dbh significantly predicted liana species richness and structure in the study (). On the basis of the importance value index, three main liana communities, each corresponding with a forest type, were identified. Stepwise multiple regression analysis revealed that exchangeable magnesium and calcium, and total exchangeable bases were the main soil variables that affected liana species richness. Liana structure was influenced by the above-mentioned soil variables as well as exchangeable potassium and sodium, and pH. The present study has demonstrated that changes in liana species richness and structure following human disturbance may be due to variations in soil properties and forest structure.


2020 ◽  
Vol 153 (1) ◽  
pp. 12-21
Author(s):  
Derio A. Jiménez-López ◽  
Rubén Martínez-Camilo ◽  
Nayely Martínez-Meléndez ◽  
Michael Kessler

Background and aims – In the tropics, some studies have found that the richness of epiphytic ferns present a peak at mountain mid-elevations. However, it is not well understood how transitions from tropical to subtropical conditions affect this peak, and even less is known about beta diversity of epiphytic ferns. Thus, the objective is to understand the effect of climatic gradients on the variation of local richness of ferns and beta diversity patterns along an elevational gradient in a mountain system in southern Mexico.Methods – We sampled 32 trees, each in four elevational bands (100–2200 m). Alpha diversity patterns were analysed using linear regression models. We used the Morisita index to quantify species turnover between bands. An additive partitioning approach was used to analyse the degree to which individual trees, plots, and bands contributed to total species richness. We evaluated the influence of climatic variables on species composition via linear regression models.Key results – A total of 30 species in five families were recorded. Each family contributed in different magnitude to the elevational richness pattern, with Polypodiaceae dominating due to its richness and presence along the entire transect. Alpha diversity at the three scales (αtree, αplot, αband) increased with elevation and rainfall, and with decreasing temperature. Species turnover was high along the gradient, but was scale-dependent, with βtransect (65–75%) and βband (14%) with the greatest contributing to total diversity. Although the contribution of the individual trees was lower, it increased with elevation. Conclusions – We emphasize the importance of including different scale levels in analyses of diversity along elevational gradients. In the region, cloud forest on the mountain peaks harbours the highest diversity of epiphytic fern communities. Due to a limited extent of this mountain range, the epiphyte ferns are susceptible to the effects of climate change.


2014 ◽  
Vol 30 (5) ◽  
pp. 381-399 ◽  
Author(s):  
Joseph E. Hawes ◽  
Carlos A. Peres

Abstract:Constructing community fruit–frugivore networks has proved challenging in tropical forests to date, particularly in lowland Amazonia, which hosts the most diverse spectrum of frugivorous vertebrates and morphological fruit types worldwide. We assessed data on fruit resource production, frugivore assemblages and corresponding fruit–frugivore networks in two contrasting forest types along the Rio Juruá of western Brazilian Amazonia: seasonally flooded várzea (VZ) and unflooded terra firme forest (TF). Over 2 y we conducted monthly surveys of fruit patches and medium- to large-bodied vertebrate frugivores within three 100-ha plots (two TF, one VZ), supplemented by fruit surveys along 67 5-km transects distributed across two contiguous forest reserves (41 TF, 26 VZ). Observations of trophic interactions were supplemented by semi-structured interviews with experienced hunters and fishermen from 16 local communities. The resultant binary networks contained low proportions of all potential interactions (TF: 25.7%, VZ: 19.4%) between 36 functional groups of frugivores and 152 plant genera and, while we report significant heterogeneity in fruit resource use among broad frugivore guilds within each forest type, recursive partitioning analysis failed to clearly match differences in fruit selection to fruit traits. The annual flood pulse in várzea forests had an overriding influence on the species turnover of both fruit resources and frugivores between the two forest types, with higher-order effects on network structure.


2020 ◽  
Vol 68 (1) ◽  
Author(s):  
Armando Luis-Martínez ◽  
Alejandra Sánchez García ◽  
Omar Ávalos-Hernández ◽  
José Luis Salinas-Gutiérrez ◽  
Marysol Trujano-Ortega ◽  
...  

Introduction: A reliable list of species and the analysis of diversity patterns of hyperdiverse taxa, like butterflies, are fundamental for monitoring and managing biological resources. Oaxaca is one of the most diverse states in Mexico for many groups including Lepidoptera and most of its diversity is unknown. Objective: to estimate and describe the species richness and diversity of Papilionidae and Pieridae along an altitudinal gradient and five vegetation types in the Loxicha Region, Oaxaca, Sierra Madre del Sur. Methods: Sampling effort comprised 222 collecting days during a period of seven years. We estimated the alpha diversity for 17 sites within an elevational gradient from 80 to 2 850 m, with five vegetation types: tropical deciduous forest (TDF), tropical sub-deciduous forest (TSDF), cloud forest (low and middle levels) (CF), oak-pine and cloud forest (high level) (OPCF) and oak-pine forest (OPF). Results: We obtained a list of 69 species (27 Papilionidae and 42 Pieridae), of 34 genera and five subfamilies, from literature records and fieldwork. These species are 60 % of the Pieridae and 48 % of the Papilionidae recorded for the state. The Loxicha Region has 36 % of the Pieridae and 30 % of the Papilionidae of Mexico. Both families present different species richness patterns by vegetation type. Papilionidae is richer in the TDF with 23 estimated species and most of the species of this family (84 %) occur below 500 m. Meanwhile, species richness of Pieridae has non-significant differences among vegetations types, except for OPF which has fewer species than the other types. The elevational gradient was divided into three levels (0-750, 750-1 800, 1 800-2 850 m) showing a reduction of species richness and diversity for both families at higher altitudes. Conclusions: Papilionidae species are more restricted to a vegetation type or elevational level than Pieridae species. Likely reasons are higher vagility (including migrations) and wider ecological tolerance of most Pieridae.


Author(s):  
Mauro Gobbi ◽  
Valeria Lencioni

Carabid beetles and chironomid midges are two dominant cold-adapted taxa, respectively on glacier forefiel terrains and in glacial-stream rivers. Although their sensitivity to high altitude climate warming is well known, no studies compare the species assemblages exhibited in glacial systems. Our study compares diversity and distributional patterns of carabids and chironomids in the foreland of the receding Amola glacier in central-eastern Italian Alps. Carabids were sampled by pitfall traps; chironomids by kick sampling in sites located at the same distance from the glacier as the terrestrial ones. The distance from the glacier front was considered as a proxy for time since deglaciation since these variables are positively correlated. We tested if the distance from the glacier front affects: i) the species richness; ii) taxonomic diversity; and iii) species turnover. Carabid species richness and taxonomic diversity increased positively from recently deglaciated sites (those c. 160 m from the glacier front) to sites deglaciated more than 160yrs ago (those located >1300 m from glacier front). Species distributions along the glacier foreland were characterized by mutually exclusive species. Conversely, no pattern in chironomid species richness and turnover was observed. Interestingly, taxonomic diversity increased significantly: closely related species were found near the glacier front, while the most taxonomically diverse species assemblages were found distant from the glacier front. Increasing glacial retreat differently affect epigeic and aquatic insect taxa: carabids respond faster to glacier retreat than do chironomids, at least in species richness and species turnover patterns.


The Condor ◽  
2021 ◽  
Author(s):  
Kyle D Kittelberger ◽  
Montague H C Neate-Clegg ◽  
Evan R Buechley ◽  
Çağan Hakkı Şekercioğlu

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.


2017 ◽  
Vol 63 (2) ◽  
pp. 8-16 ◽  
Author(s):  
Corrado Battisti ◽  
Marco Giardini ◽  
Francesca Marini ◽  
Lorena Di Rocco ◽  
Giuseppe Dodaro ◽  
...  

We reported a study on breeding birds occurring inside an 80 m-deep karst sinkhole, with the characterization of the assemblages recorded along its semi-vertical slopes from the upper edge until the bottom. The internal sides of the sinkhole have been vertically subdivided in four belts about 20 m high. The highest belt (at the upper edge of the cenote) showed the highest values in mean number of bird detections, mean and normalized species richness, and Shannon diversity index. The averaged values of number of detections and species richness significantly differ among belts. Species turnover (Cody’s β-diversity) was maximum between the highest belts. Whittaker plots showed a marked difference among assemblages shaping from broken-stick model to geometric series, and explicited a spatial progressive stress with a disruption in evenness towards the deepest belts. Bird assemblages evidenced a nested subset structure with deeper belts containing successive subsets of the species occurring in the upper belts. We hypothesize that, at least during the daytime in breeding season, the observed non-random distribution of species along the vertical stratification is likely due to (i) the progressive simplification both of the floristic composition and vegetation structure, and (ii) the paucity of sunlight as resources from the upper edge to the inner side of the cenote.


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