scholarly journals Combining point counts and autonomous recording units improves avian survey efficacy across elevational gradients on two continents

2021 ◽  
Author(s):  
Anna Drake ◽  
Devin R. Zwaan ◽  
Tomás A. Altamirano ◽  
Scott Wilson ◽  
Kristina Hick ◽  
...  
Keyword(s):  
Elevational Gradients ◽  
Point Counts

scholarly journals Combining point counts and autonomous recording units improves survey efficacy across elevational gradients on two continents

2021 ◽  
Author(s):  
Anna Drake ◽  
Devin de Zwaan ◽  
Tomás Altamirano ◽  
Scott Wilson ◽  
Kristina Hick ◽  
...  
Keyword(s):  
Detection Probability ◽  
Canopy Cover ◽  
Population Monitoring ◽  
Landscape Composition ◽  
Survey Method ◽  
Elevational Gradients ◽  
Point Counts ◽  
Time Costs ◽  
Mountain Habitats ◽  
Combined Methods

1. Accurate biodiversity and population monitoring is a requirement for effective conservation decision-making. Survey method bias is therefore a concern, particularly when research programs face logistical and cost limitations. 2. We employed point counts (PCs) and autonomous recording units (ARUs) to survey avian biodiversity across elevational gradients in comparable temperate mountain habitats at opposite ends of the Americas (9 mountains in British Columbia (BC), Canada and 10 in southern Chile). We compared detected species richness against multi-year species inventories and examined differences in detection probability by family. By incorporating time costs, we assessed the performance and efficiency of single vs. combined methods. 3. ARUs were predicted to capture ~92% of species present in BC but only ~58% in Chile, despite Chilean mountain communities being less diverse. Community, rather than landscape composition, appears to be the driver of this dramatic difference. Chilean communities contain less-vocal species, which ARUs missed. Further, 6/14 families in BC were better detected by ARUs while 11/11 families in Chile were better detected by PCs. Where survey conditions differentially impacted methods, PC detection varied over the morning and with canopy cover in BC and ARU detection probability mostly varied seasonally in Chile. Within a single year of monitoring, neither method alone was predicted to capture the full avian community, with the exception of ARUs in the alpine and subalpine of BC. PCs contributed little to detected diversity in BC, but including this method resulted in negligible increases in total time costs. Combining PCs with ARUs in Chile significantly increased species detections, again, for little cost. 4. Combined methods were among the most efficient and accurate approaches to capturing diversity. We recommend conducting observer point counts, where possible, when ARUs are deployed and retrieved, in order to capture additional diversity and flag methodology biases with minimal additional effort.

scholarly journals Diversity of Birds Along an Elevational Gradient in The Cordillera Central, Costa Rica

The Auk ◽  
2000 ◽  
Vol 117 (3) ◽  
pp. 663-686 ◽  
Author(s):  
John G. Blake ◽  
Bette A. Loiselle
Keyword(s):  
Costa Rica ◽  
Threatened Species ◽  
Rain Forest ◽  
Elevational Gradient ◽  
Elevational Gradients ◽  
Cordillera Central ◽  
Montane Rain Forest ◽  
Point Counts ◽  
Tropical Wet Forest ◽  
Valuable Complement

Abstract Species diversity and community composition of birds change rapidly along elevational gradients in Costa Rica. Such changes are of interest ecologically and illustrate the value of protecting continuous gradients of forest. We used mist nets and point counts to sample birds along an elevational gradient on the northeastern Caribbean slope of the Cordillera Central in Costa Rica. Sites included mature tropical wet forest (50 m); tropical wet, cool transition forest (500 m); tropical premontane rain forest (1,000 m); and tropical lower montane rain forest (1,500 and 2,000 m). We recorded 261 species from 40 families, including 168 species captured in mist nets (7,312 captures) and 226 detected during point counts (17,071 observations). The sample included 40 threatened species, 56 elevational migrants, and 22 latitudinal migrants. Species richness (based on rarefaction analyses) changed little from 50 to 1,000 m but was lower at 1,500 and 2,000 m. Mist nets and point counts often provided similar views of community structure among sites based on relative importance of difference categories of species (e.g. migrant status, trophic status). Nonetheless, important differences existed in numbers and types of species represented by the two methods. Ninety-three species were detected on point counts only and 35 were captured only. Ten families, including ecologically important ones such as Psittacidae and Cotingidae, were not represented by captures. Elevational migrants and threatened species occurred throughout the gradient, illustrating the need to protect forest at all elevations. A comparable study from the Cordillera de Tilarán (Young et al. 1998) demonstrated similar patterns of species change along an elevational gradient. Comparisons with that study illustrated that point counts are a valuable complement to mist-net studies. Both studies indicated the diverse nature of the avifauna along elevational gradients in Costa Rica.

Santa Fe Watershed Fuels Reduction Project: Avian Point Counts

2012 ◽  
Author(s):  
Karen E. Bagne ◽  
Deborah M. Finch
Keyword(s):  
Santa Fe ◽  
Fuels Reduction ◽  
Point Counts

Die Brutvogelfauna eines Nadelwaldes der nördlichen Voralpen nach dem Sturm Lothar

2017 ◽  
Vol 168 (2) ◽  
pp. 59-66
Author(s):  
Pierre Mollet ◽  
René Hardegger ◽  
Res Altwegg ◽  
Pius Korner ◽  
Simon Birrer
Keyword(s):  
Forest Succession ◽  
Coniferous Forest ◽  
Bird Species ◽  
Individual Species ◽  
Mountain Forest ◽  
Breeding Bird ◽  
Point Counts ◽  
Federal Institute ◽  
Central Switzerland ◽  
Bird Fauna

Breeding bird fauna in a coniferous forest in the northern Prealps after storm Lothar In a 70-hectare large coniferous forest located on the northern edge of the Alps in central Switzerland, Canton of Obwalden, at an altitude of 1260 to 1550 metres above sea level, we surveyed the local breeding bird fauna in 2002 and 2013 by means of point counts as well as additional area searches for rare species. In December 1999, hurricane Lothar caused two large windthrow areas and several smaller areas with scattered throws in the survey range. We found a total of 48 breeding bird species, which is a very diverse species composition for a mountain forest. In the eleven years between surveys, a decline in distribution or abundance was recorded for four species, while seven species showed an increase; a further four species showed no change. For the remaining species, the data sets were too small to reliably estimate changes. A comparison with forest structure data provided by the Swiss Federal Institute of Forest, Snow and Landscape Research WSL revealed that for five bird species, the changes in distribution or abundance could be explained at least partially by forest succession. In order to obtain realistic distribution and abundance values in this kind of breeding bird survey, it is essential to collect large enough samples and to consider the detection probability of each individual species using appropriate statistical methods.

Evolutionary history, not ecogeographic rules, explains size variation of tropical insects along elevational gradients

2020 ◽  
Vol 34 (12) ◽  
pp. 2513-2523
Author(s):  
Carlos Garcia‐Robledo ◽  
Christina S. Baer ◽  
Kes Lippert ◽  
Vikas Sarathy
Keyword(s):  
Evolutionary History ◽  
Size Variation ◽  
Elevational Gradients

Phenotypic and genomic diversification with isolation by environment along elevational gradients in a neotropical treefrog

2021 ◽  
Author(s):  
Ricardo Medina ◽  
Guinevere O.U. Wogan ◽  
Ke Bi ◽  
Flavia Termignoni‐García ◽  
Manuel Hernando Bernal ◽  
...  
Keyword(s):  
Elevational Gradients ◽  
Isolation By Environment

Stand-Level Forest Structure and Avian Habitat: Scale Dependencies in Predicting Occurrence in a Heterogeneous Forest

2008 ◽  
Vol 54 (1) ◽  
pp. 36-46
Author(s):  
Katherine Manaras Smith ◽  
William S. Keeton ◽  
Therese M. Donovan ◽  
Brian Mitchell
Keyword(s):  
Forest Structure ◽  
Stand Structure ◽  
Site Occupancy ◽  
Territory Size ◽  
Weight Of Evidence ◽  
Habitat Models ◽  
Point Counts ◽  
Forest Stand Structure ◽  
Habitat Scale

Abstract We explored the role of stand-level forest structure and spatial extent of forest sampling in models of avian occurrence in northern hardwood-conifer forests for two species: black-throated blue warbler (Dendroica caerulescens) and ovenbird (Seiurus aurocapillus). We estimated site occupancy from point counts at 20 sites and characterized the forest structure at these sites at three spatial extents (0.2, 3.0, and 12.0 ha). Weight of evidence was greatest for habitat models using forest stand structure at the 12.0-ha extent and diminished only slightly at the 3.0-ha extent, a scale that was slightly larger than the average territory size of both species. Habitat models characterized at the 0.2-ha extent had low support, yet are the closest in design to those used in many of the habitat studies we reviewed. These results suggest that the role of stand-level vegetation may have been underestimated in the past, which will be of interest to land managers who use habitat models to assess the suitability of habitat for species of concern.

scholarly journals Noctuid and geometrid moth assemblages show divergent elevational gradients in body size and color lightness

Ecography ◽  
2021 ◽  
Author(s):  
Lea Heidrich ◽  
Stefan Pinkert ◽  
Roland Brandl ◽  
Claus Bässler ◽  
Hermann Hacker ◽  
...  
Keyword(s):  
Body Size ◽  
Elevational Gradients ◽  
Geometrid Moth

What drives species’ distributions along elevational gradients? Macroecological and ‐evolutionary insights from Brassicaceae of the central Alps

2021 ◽  
Vol 30 (5) ◽  
pp. 1030-1042
Author(s):  
Theofania‐Sotiria Patsiou ◽  
Nora Walden ◽  
Yvonne Willi
Keyword(s):  
Species Distributions ◽  
Central Alps ◽  
Elevational Gradients
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