scholarly journals Patch size and vegetation structure drive changes to mixed-species flock diversity and composition across a gradient of fragment sizes in the Western Andes of Colombia

The Condor ◽  
2020 ◽  
Vol 122 (2) ◽  
Author(s):  
Harrison H Jones ◽  
Scott K Robinson
Keyword(s):  
Species Richness ◽  
Functional Diversity ◽  
Edge Effects ◽  
Vegetation Structure ◽  
Phylogenetic Diversity ◽  
Patch Size ◽  
Forest Edge ◽  
Mixed Species ◽  
Functional And Phylogenetic Diversity ◽  
Diversity Metrics

Abstract Forest fragmentation is a leading driver of biodiversity loss, yet its effects on positive species interactions remain poorly known. We examined the effects of fragmentation on mixed-species bird flocks in the Western Andes of Colombia. Using 500-m transect surveys (n = 14 transects), we sampled flocks in 8 fragments (range: 10–173 ha) and an unfragmented reference site within the same altitudinal band (1,900–2,200 m.a.s.l.) and matrix type (cattle pasture). We evaluated the relative contributions of 9 predictor variables, including patch size, distance from edge, and selective aspects of vegetation structure on the composition, size, species richness, functional diversity, and phylogenetic diversity of flocks. We found effects of both patch size and vegetation structure on flock species richness, size, and functional diversity, but no support for edge effects. Generally, flock richness and size responded differently to fragmentation than did functional and phylogenetic diversity metrics. Both flock size and richness increased with patch size, but this variable had no effect on functional and phylogenetic diversity. Flock richness and size increased in high-canopy forests with greater foliage height diversity, whereas unlogged, old-growth primary forests with large-diameter trees had lower flock richness and size, but significantly greater functional diversity. Phylogenetic diversity was not affected by patch size, edge effects, or vegetation structure. We found differences in flock composition in response to fragmentation. Richness of Furnariidae in flocks increased with increasing distance from edge and foliage height diversity, whereas that of Thraupidae and boreal migrant species increased in early successional and forest edge flocks, respectively. All flock diversity metrics differed significantly seasonally, with smaller, less diverse flocks observed in January–March than in June–August. Flocking behavior persisted in 10-ha fragments, likely because Andean flocks are “open membership” in nature, but there was extensive species turnover as forest edge and generalist species replaced forest-interior species in smaller fragments.

scholarly journals Functional diversity of Himalayan bat communities declines at high elevation without the loss of phylogenetic diversity

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Rohit Chakravarty ◽  
Ram Mohan ◽  
Christian C. Voigt ◽  
Anand Krishnan ◽  
Viktoriia Radchuk
Keyword(s):  
Species Richness ◽  
Functional Diversity ◽  
Phylogenetic Diversity ◽  
Environmental Filtering ◽  
Taxonomic Diversity ◽  
High Elevation ◽  
Elevational Gradients ◽  
Functional Richness ◽  
Functional Dispersion ◽  
Functional And Phylogenetic Diversity

AbstractSpecies richness exhibits well-known patterns across elevational gradients in various taxa, but represents only one aspect of quantifying biodiversity patterns. Functional and phylogenetic diversity have received much less attention, particularly for vertebrate taxa. There is still a limited understanding of how functional, phylogenetic and taxonomic diversity change in concert across large gradients of elevation. Here, we focused on the Himalaya—representing the largest elevational gradients in the world—to investigate the patterns of taxonomic, functional and phylogenetic diversity in a bat assemblage. Combining field data on species occurrence, relative abundance, and functional traits with measures of phylogenetic diversity, we found that bat species richness and functional diversity declined at high elevation but phylogenetic diversity remained unchanged. At the lowest elevation, we observed low functional dispersion despite high species and functional richness, suggesting a niche packing mechanism. The decline in functional richness, dispersion, and divergence at the highest elevation is consistent with patterns observed due to environmental filtering. These patterns are driven by the absence of rhinolophid bats, four congeners with extreme trait values. Our data, some of the first on mammals from the Himalayan region, suggest that in bat assemblages with relatively high species diversity, phylogenetic diversity may not be a substitute to measure functional diversity.

scholarly journals Assessing Functional Diversity-Productivity Relationships in Temperate Forests in Northern Mexico

2020 ◽  
Author(s):  
Benedicto Vargas-Larreta ◽  
Jorge O. López-Martínez ◽  
Jose Javier Corral-Rivas ◽  
Francisco Javier Hernández
Keyword(s):  
Species Richness ◽  
Functional Diversity ◽  
Biomass Production ◽  
Temperate Forests ◽  
Taxonomic Diversity ◽  
Mass Ratio ◽  
Above Ground Biomass ◽  
Northern Mexico ◽  
Ground Biomass ◽  
Diversity Metrics

Abstract Background: Studies on the relationships between biodiversity and ecosystem productivity have suggested that species richness and functional diversity are the main drivers of ecosystem processes. There is no general pattern regarding the relationship found in various studies, and positive, unimodal, negative, and neutral relationships keep the issue controversial. In this study, taxonomic diversity vs functional diversity as drivers of above-ground biomass were compared, and the mechanisms that influence biomass production were investigated by testing the complementarity and the mass-ratio hypoteses.Methods: Using data from 414 permanent sampling plots, covering 23% of temperate forests in the Sierra Madre Occiental (Mexico), we estimated the above-ground biomass (AGB) for trees ≥7.5 cm d.b.h. in managed and unmanaged stands. We evaluated AGB-diversity relationships (species richness, Shannon-Wiener and Simpson indices), AGB-weighted mean community values ​​(CWM) of tree species functional traits (maximum height, leaf size, and wood density) and five measures of functional diversity (functional dispersion, functional richness, functional uniformity, functional diversity, and RaoQ index).Results: We reveal a consistent hump-shaped relationship between aboveground biomass and species richness in managen and unmanaged forest. CWM_Hmax was the most important predictor of AGB in both managed and unmanaged stands, which suggests that the mechanism that explains the above-ground biomass in these ecosystems is dominated by certain highly productive species in accordance of the mass-ratio hypothesis. There were no significant relationships between taxonomic diversity metrics (Shannon-Wiener and Simpson indices) or measures of functional diversity with AGB. The results support the mass-ratio hypothesis to explain the AGB variations.Conclusions: We concluded that diversity does not influence biomass production in the temperate mixed-species and uneven-aged forests of northern Mexico. These forests showed the classic hump-shaped productivity-species richness relationship, with biomass accumulation increasing at low to intermediate levels of species plant diversity and decreasing at high species richness. Functional diversity explains better forest productivity than classical diversity metrics.

Assessment of the network of protected areas for birds in Taiwan with regard to functional and phylogenetic diversity

2016 ◽  
Vol 22 (1) ◽  
pp. 61 ◽  
Author(s):  
Hungyen Chen ◽  
Satoshi Nagai ◽  
Hirohisa Kishino
Keyword(s):  
Species Richness ◽  
Protected Areas ◽  
Phylogenetic Trees ◽  
Phylogenetic Diversity ◽  
Bird Species ◽  
Elevational Gradient ◽  
Mountain Areas ◽  
Phylogenetic Constraint ◽  
Lower Elevation ◽  
Functional And Phylogenetic Diversity

In Taiwan, conserved areas represent more than 20% of the current jurisdiction, which is about twice that of the proportion of protected land worldwide. In this study, we explored the spatial distribution of bird assemblages in Taiwan. By analysing functional and phylogenetic diversity relative to elevational gradient, we assessed the network of bird protected areas. Hotspots of species richness were located at the coastal areas of northern and western Taiwan, although hotspots for protected bird species were located in the mountain areas. We found that phylogenetically close birds have similar trait values, and the protected species were evenly distributed in the functional and phylogenetic trees. The assemblages in higher-elevation areas were more phylogenetically clumped than those in lower-elevation areas, indicating that, in addition to elevational gradient, phylogenetic constraint may be a crucial factor that influences bird distribution in Taiwan. However, the current bird protected areas in Taiwan may overly depend on species richness and overlook the importance of the overall phylogenetic diversity.

scholarly journals Edge effects in the avifaunal community of riparian rain-forest tracts in Tropical North Queensland

2016 ◽  
Vol 32 (4) ◽  
pp. 280-289 ◽  
Author(s):  
Montague H. C. Neate-Clegg ◽  
Emily C. Morshuis ◽  
Cristina Banks-Leite
Keyword(s):  
Species Richness ◽  
Community Composition ◽  
Edge Effects ◽  
Rain Forest ◽  
Forest Edge ◽  
Bird Communities ◽  
Forest Bird ◽  
Resource Distributions ◽  
Detection Frequency ◽  
Open Canopy

AbstractMost evidence suggests anthropogenic edges negatively affect rain-forest bird communities but little has been done to test this in Australasia. In this study, avifaunal detection frequency, species richness and community composition were compared between the edge and interior and between flat and more complex-shaped edges of riparian rain-forest tracts in Tropical North Queensland. The detection frequency and richness of guilds based on diet, foraging strata and habitat specialism were also compared. This study detected 15.1% more birds at the rain-forest edge compared with the interior but no difference in species richness. Edge shape had no effect on detection frequency or richness. Many guilds (subcanopy, closed forest, frugivorous and insectivorous species) experienced increased detection frequency at the edge relative to the interior, but for some guilds this response was reduced (habitat generalists) or reversed (understorey and mixed-flock species) along complex edges. Overall community composition was affected by edge distance but not by edge shape. Edge habitat was shorter and had more open canopy than the interior, supporting habitat-based explanations for the observed avifaunal edge effects. These results suggest generally positive edge effects in Australian rain-forest bird communities, possibly reflecting local resource distributions or a disturbance-tolerant species pool.

Assessing rainforest restoration: the value of buffer strips for the recovery of rainforest remnants in Australia?s Wet Tropics

2010 ◽  
Vol 16 (4) ◽  
pp. 274 ◽  
Author(s):  
Laura J. Sonter ◽  
Daniel J. Metcalfe ◽  
Margaret M. Mayfield
Keyword(s):  
Functional Diversity ◽  
Edge Effects ◽  
Functional Trait ◽  
Forest Edge ◽  
Physical Structure ◽  
Buffer Strips ◽  
Buffer Strip ◽  
Restoration Technique ◽  
Forest Remnants ◽  
Interior Forest

Throughout the tropics, forest remnants are under increasing pressure from habitat fragmentation and edge effects. To improve the conservation value of forest remnants, restoration plantings are used to accelerate and redirect ecological succession. Unfortunately, many restoration projects undergo little to no evaluation in achieving project goals. Here we evaluate the success of one common restoration technique, ?buffer strip planting,? at the Malanda Scrub in North Queensland, Australia. Buffer strips are used to reduce the impacts associated with edge effects and improve overall forest quality. To evaluate the success of the Malanda project, we compared the microclimate, understorey community structure and functional trait-state diversity (functional diversity) for a range of plant functional traits along the original forest edge, a reference forest edge, and the interior forest of the Malanda reserve. We found the buffer strip restored the original forest edge to interior forest conditions for the majority of measured features. Edge effects were not found more than 5 m from any measured edge, and edge effects penetrated to even shorter distances along the buffer strip edge. The buffer strip appeared to have a similar microclimate (here represented by soil temperature) and physical structure; however, it did not (after 14 years) closely resemble the interior forest floristically nor did it have the same functional diversity for measured traits. Results suggest that the buffer strip was successful in reducing edge effects but not in restoring the forest to original conditions within 14 years.

Phylogenetic diversity metrics for ecological communities: integrating species richness, abundance and evolutionary history

2010 ◽  
Vol 13 (1) ◽  
pp. 96-105 ◽  
Author(s):  
Marc W. Cadotte ◽  
T. Jonathan Davies ◽  
James Regetz ◽  
Steven W. Kembel ◽  
Elsa Cleland ◽  
...  
Keyword(s):  
Species Richness ◽  
Evolutionary History ◽  
Phylogenetic Diversity ◽  
Ecological Communities ◽  
Diversity Metrics

Edge effects on nest predators in two forested landscapes

2004 ◽  
Vol 82 (12) ◽  
pp. 1943-1953 ◽  
Author(s):  
Michelle L Smith
Keyword(s):  
Species Richness ◽  
Edge Effects ◽  
Spatial Scales ◽  
Forest Edge ◽  
Tamiasciurus Hudsonicus ◽  
Brood Parasite ◽  
Camera Systems ◽  
Total Species Richness ◽  
Edge Response ◽  
Nest Predators

Few studies have systematically examined edge effects on nest predators, although many invoke these processes as potential mechanisms for decreased nesting success of songbirds. Species richness and relative abundance of avian and mammalian nest predators were compared between forest edge and interior in two landscapes, Allegan State Game Area and Fort Custer Training Center (FCTC), in southwest Michigan. One avian predator, the American crow (Corvus brachyrhynchos Brehm, 1822), was more abundant at edges than forest interior at FCTC; however, other predators did not demonstrate an edge response. Abundance of the brood parasite (Molothrus ater (Boddaert, 1783)) was greater at edges in FCTC. Overall abundance was higher at FCTC in both years; however, this could not be attributed to a greater extent of fragmentation. Total species richness for both landscapes did not differ between edge and interior. Remote-camera systems captured three predation events, two involving red squirrels (Tamiasciurus hudsonicus (Erxleben, 1777)) and one involving a blue jay (Cyanocitta cristata (L., 1758)). Vegetation characteristics were similar between edge and interior sites, which suggests that vegetation structure did not influence edge response. The variability in response indicates a need to assess patterns of predator distributions through long-term studies at multiple spatial scales.

Are leaf-litter frogs and lizards affected by edge effects due to forest fragmentation in Brazilian Atlantic forest?

2008 ◽  
Vol 24 (05) ◽  
pp. 551-554 ◽  
Author(s):  
Marianna Dixo ◽  
Marcio Martins
Keyword(s):  
Edge Effects ◽  
Vegetation Structure ◽  
Environmental Changes ◽  
Forest Edge ◽  
Habitat Types ◽  
Abiotic Conditions ◽  
Freshwater Habitats ◽  
Ecological Patterns ◽  
Predominant Factor ◽  
Landscape Level

Edge effects encompass biotic and abiotic changes resulting from the interaction between two different habitat types (Murcia 1995). Edge habitats are ecologically distinct from patch interiors, and understanding how ecological patterns change near edges is important in understanding landscape-level dynamics such as the impacts of fragmentation (Rieset al. 2004). Abiotic conditions at the forest edge, such as increased wind and solar radiation, increased fluctuations in temperature, and decreased humidity, may affect forest-adapted organisms (Harperet al. 2005, Murcia 1995). So, edges may affect lizards and amphibians due to their physiological needs (Lehtinenet al. 2003, Vallan 2000). Anurans are considered sensitive to environmental changes due to their permeable skin, shell-less eggs and use of land as well as freshwater habitats (Vallan 2000). Changes in vegetation structure and microclimate are likely to be the predominant factor affecting amphibian abundances across edges (Jellineket al. 2004, Marsh & Pearman 1997, Schaepfer & Gavin 2001, Urbina-Cardonaet al. 2006).

Complex edge effects on soil moisture and microclimate in central Amazonian forest

1995 ◽  
Vol 11 (2) ◽  
pp. 205-221 ◽  
Author(s):  
J. L. C. Camargo ◽  
V. Kapos
Keyword(s):  
Soil Moisture ◽  
Edge Effects ◽  
Vegetation Structure ◽  
Vapour Pressure ◽  
Vapour Pressure Deficit ◽  
Forest Edge ◽  
Vertical Profiles ◽  
Control Soil ◽  
Neutron Probe ◽  
Microclimatic Conditions

ABSTRACTWe investigated the influence of a four-year-old forest edge near Manaus, Brazil, on soil moisture and vertical profiles of air vapour pressure deficit (VPD) within the forest. Soil moisture was measured (with a neutron probe) 0, 5, 10, 20, 40, 60, 80, 100, 150 and 200 m into the forest from the edge, in undisturbed control areas, and in the pasture. Control soil moisture was better explained by rainfall in the previous 2 or 10 days than by longer-term totals. Soil water potentials ≤ – 1.5 MPa occurred at some forest locations during the driest period. The variation in soil moisture with distance from the forest edge was complex, with higher values just inside the edge and depleted zones at the edge and 40–80 m inside it. At a given height, VPD (standardized relative to measurements in the open) was not related to distance from the edge, but VPD increased more with height near the edge than in control areas. The complexity of the edge's influence and the contrast with earlier data from the same edge can be explained by the changing vegetation structure near the edge. Regrowth ‘seals’ the edge with more leaves that transpire and deplete soil moisture, while protecting the understorey just inside the edge from desiccating conditions. A mosaic of gaps of differing ages develops behind the edge, increasing the variation in microclimatic conditions near the ground and consequently in evapotranspiration and soil moisture.

scholarly journals Plant community diversity will decline more than increase under climatic warming

2020 ◽  
Vol 375 (1794) ◽  
pp. 20190106 ◽  
Author(s):  
Susan Harrison
Keyword(s):  
Climate Change ◽  
Species Richness ◽  
Plant Community ◽  
Phylogenetic Diversity ◽  
Community Diversity ◽  
Climatic Warming ◽  
Theme Issue ◽  
Local Species Richness ◽  
Local Species ◽  
Functional And Phylogenetic Diversity

Regions and localities may lose many species to extinction under rapid climate change and may gain other species that colonize from nearby warmer environments. Here, it is argued that warming-induced species losses will generally exceed gains and there will be more net declines than net increases in plant community richness. Declines in richness are especially likely in water-limited climates where intensifying aridity will increasingly exceed plant tolerances, but also in colder temperature-limited climates where steep climatic gradients are lacking, and therefore, large pools of appropriate species are not immediately adjacent. The selectivity of warming-induced losses may lead to declines in functional and phylogenetic diversity as well as in species richness, especially in water-limited climates. Our current understanding of climate-caused diversity trends may be overly influenced by numerous studies coming from north-temperate alpine mountaintops, where conditions are unusually favourable for increases—possibly temporary—in local species richness. This article is part of the theme issue ‘Climate change and ecosystems: threats, opportunities and solutions’.

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