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.

scholarly journals Altitudinal Vascular Plant Richness and Climate Change in the Alpine Zone of the Lefka Ori, Crete

Diversity ◽  
2021 ◽  
Vol 13 (1) ◽  
pp. 22
Author(s):  
George Kazakis ◽  
Dany Ghosn ◽  
Ilektra Remoundou ◽  
Panagiotis Nyktas ◽  
Michael A. Talias ◽  
...  
Keyword(s):  
Climate Change ◽  
Species Richness ◽  
Spatial Scales ◽  
Vascular Plant ◽  
Monitoring Network ◽  
Mediterranean Area ◽  
Mean Annual Temperature ◽  
High Mountain ◽  
Species Loss ◽  
Total Species Richness

High mountain zones in the Mediterranean area are considered more vulnerable in comparison to lower altitudes zones. Lefka Ori massif, a global biodiversity hotspot on the island of Crete is part of the Global Observation Research Initiative in Alpine Environments (GLORIA) monitoring network. The paper examines species and vegetation changes with respect to climate and altitude over a seven-year period (2001–2008) at a range of spatial scales (10 m Summit Area Section-SAS, 5 m SAS, 1 m2) using the GLORIA protocol in a re-survey of four mountain summits (1664 m–2339 m). The absolute species loss between 2001–2008 was 4, among which were 2 endemics. At the scale of individual summits, the highest changes were recorded at the lower summits with absolute species loss 4 in both cases. Paired t-tests for the total species richness at 1 m2 between 2001–2008, showed no significant differences. No significant differences were found at the individual summit level neither at the 5 m SAS or the 10 m SAS. Time series analysis reveals that soil mean annual temperature is increasing at all summits. Linear regressions with the climatic variables show a positive effect on species richness at the 5 m and 10 m SAS as well as species changes at the 5 m SAS. In particular, June mean temperature has the highest predictive power for species changes at the 5 m SAS. Recorded changes in species richness point more towards fluctuations within a plant community’s normal range, although there seem to be more significant diversity changes in higher summits related to aspects. Our work provides additional evidence to assess the effects of climate change on plant diversity in Mediterranean mountains and particularly those of islands which remain understudied.

scholarly journals Bats (Mammalia: Chiroptera) from a remnant of Atlantic Forest in Pernambuco, northeastern Brazil

2017 ◽  
Vol 18 (1) ◽  
Author(s):  
Fabio Angelo Melo Soares ◽  
Carlos Eduardo Borges Pinto Ribeiro ◽  
Marcela Regina de Melo Daher ◽  
Deoclécio de Queiroz Guerra ◽  
Stephen Ferrari
Keyword(s):  
Species Richness ◽  
Atlantic Forest ◽  
Forest Edge ◽  
The State ◽  
Northeastern Brazil ◽  
Stepping Stone ◽  
Total Species Richness ◽  
The Family ◽  
Total Species

The RPPN Carnijó (08° 07’ 07” S, 35° 05’ 32” N) is a 25 hectare fragment of Atlantic Forest located in the municipality of Moreno, Pernambuco. Bats were sampled at this site during a total of 19 months between 2006 and 2008. Four mist-nets were set for six hours each night along trails, the forest edge, natural clearings, and over watercourses, while roosts were located during daytime searches. A total of 518 specimens were captured during 43 nights, representing 20 species in 16 genera. Total species richness was estimated to be 25.7 ± 2.0, and diversity was H’ = 2.07. The family Phyllostomidae predominated, with 98% (N = 509) of the specimens captured. The species recorded represent 28% of the known chiropteran fauna of the state of Pernambuco. The results indicate that the reserve may play a fundamentally important role in the maintenance of local biodiversity by acting as a “stepping stone” linking the larger fragments within the local landscape.

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.

Indicators of avian nest predation and parental activity in a managed boreal forest: an assessment at two spatial scales

2005 ◽  
Vol 35 (2) ◽  
pp. 374-382 ◽  
Author(s):  
Jacques Ibarzabal ◽  
André Desrochers
Keyword(s):  
Landscape Structure ◽  
Nest Predation ◽  
Spatial Scales ◽  
Edge Length ◽  
Nesting Success ◽  
Tamiasciurus Hudsonicus ◽  
Indirect Measure ◽  
Indirect Measures ◽  
Total Core Area ◽  
Nest Predators

Studies of avian nesting success at the landscape level often use a single indirect measure to evaluate nest predation or parental activity. During two summers at Forêt Montmorency, Quebec, we analyzed and compared three indirect measures of nest predation risk: detection of two nest predators, (1) red squirrel (Tamiasciurus hudsonicus Erxleben) and (2) gray jay (Perisoreus canadensis L.), (3) depredation of bait, and direct observations of parental activity (mostly food transported by adults) at 316 stations over a 230-km2 area. We assessed the relationship between these indicators and three landscape-structure variables (total forested area, total core area, and total edge length) at two spatial scales (83 and 1610 ha). Nest predators were generally present at <30% of stations, <20% of baits were depredated, and >40% of stations exhibited evidence of broods. Bait depredation and the detection of jays or squirrels were correlated, but we found no associations between nest predation and parental activity indicators. Indicators of nest predation and parental activity were not significantly heterogeneous over the study area, despite substantial variation of landscape structure. We argue that parental activity indicators may be more reliable than nest predation indicators, but only as a coarse way to detect variation in nesting success.

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.

Edge effects on survival and behaviour of juvenile red squirrels (Tamiasciurus hudsonicus)

2002 ◽  
Vol 80 (6) ◽  
pp. 1038-1046 ◽  
Author(s):  
Elizabeth M Anderson ◽  
Stan Boutin
Keyword(s):  
Predation Risk ◽  
Edge Effects ◽  
Nest Predation ◽  
Survival Rates ◽  
Forest Edge ◽  
Tamiasciurus Hudsonicus ◽  
Red Squirrels ◽  
Emergence Period ◽  
High Predation ◽  
Survival Differences

Much research has examined parasitism and predation rates on avian nests within the context of edge effects. Few studies, however, have considered the influence that behavioural compensation for high predation risk may have on subsequent survival rates and edge effects. We attempted to determine whether juvenile red squirrels (Tamiasciurus hudsonicus) experience edge effects by comparing the survival and behaviour of individuals born along a forest edge with those of individuals born in the forest interior. A combination of telemetry, direct observation, and livetrapping was used to determine the fate of juveniles born during the summers of 1987 through 1998 and the behaviour of juveniles born during the summers of 1997 and 1998 in Kluane, Yukon. There were no differences in survival between edge and interior juveniles from birth to emergence but there was a trend towards higher survival rates for edge juveniles from emergence to weaning. Behavioural differences between edge and interior juveniles were consistent with these survival differences: edge juveniles spent less time travelling and foraging and more time resting near the time of weaning than did interior juveniles. Edge and interior mothers differed little behaviourally during the early emergence period. The significant differences in juvenile behaviour which we found suggest that behaviour may indeed moderate differences in predation risk between edge and interior habitats and thus should be considered in other studies that examine the influence of edges on survival or nest predation.

Effects of patch size on liana diversity and distributions in the tropical montane evergreen forests of the Nilgiri Mountains, southern India

2014 ◽  
Vol 30 (6) ◽  
pp. 579-590 ◽  
Author(s):  
Dharmalingam Mohandass ◽  
Alice C. Hughes ◽  
Mason Campbell ◽  
Priya Davidar
Keyword(s):  
Species Richness ◽  
Patch Size ◽  
Forest Edge ◽  
Southern India ◽  
Patch Area ◽  
Forest Patch ◽  
Community Assemblage ◽  
Total Species Richness ◽  
Compositional Patterns ◽  
The Impact

Abstract:We investigate the effect of patch size on liana diversity and distribution in 19 patches of montane evergreen forest in the Nilgiri hills, Western Ghats, southern India. Additionally, we examined how liana species richness and community assemblage in both edge (within 10 m of the forest edge) and interior regions of forest patches respond to patch size, in order to infer the impact of forest expansion or reduction on the liana communities. A total of 1276 woody liana individuals of 15 species were identified, belonging to 10 genera and nine families. Total species richness of lianas was significantly positively related to forest-patch area, both when analysed for the entire patch, in addition to both core and edge regions when examined separately. Species richness of larger lianas also showed a significant positive relationship with increasing forest patch area. Community assemblage varied with respect to forest edge, with shade-dependent species only occurring in interior patch regions, shade-averse species in edge regions, and shade-tolerant species occurring throughout. Disturbance also played a role in determining the response of liana diversity to patch size, with heavily disturbed patches showing no relationship between patch size and diversity, whereas positive relationships exist in low to moderately disturbed patches. The most significant result is the change in liana community composition between small and larger fragments. Many species present in smaller patches are also present in edge zones of larger fragments. This suggests that lianas are important structural components of montane forest ecosystems, and their compositional patterns are possibly driven by succession. Moreover, this study reveals the importance of edge effect and patch size in influencing liana species richness and compositional patterns.

scholarly journals Fish species richness is associated with the availability of landscape components across seasons in the Amazonian floodplain

PeerJ ◽  
2018 ◽  
Vol 6 ◽  
pp. e5080 ◽  
Author(s):  
Carlos Edwar Carvalho Freitas ◽  
Laurie Laurenson ◽  
Kedma Cristine Yamamoto ◽  
Bruce Rider Forsberg ◽  
Miguel Petrere ◽  
...  
Keyword(s):  
Species Richness ◽  
Fish Species ◽  
Linear Models ◽  
Fish Assemblages ◽  
Spatial Scales ◽  
Sampling Site ◽  
Floodplain Lakes ◽  
Fish Diversity ◽  
Landscape Variables ◽  
Total Species Richness

Understanding environmental biodiversity drivers in freshwater systems continues to be a fundamental challenge in studies of their fish assemblages. The present study seeks to determine the degree to which landscape variables of Amazonian floodplain lakes influences fish assemblages in these environments. Fish species richness was estimated in 15 Amazonian floodplain lakes during the high and low-water phases and correlated with the areas of four inundated wetland classes: (i) open water, (ii) flooded herbaceous, (iii) flooded shrubs and (iv) flooded forest estimated in different radius circular areas around each sampling site. Data were analyzed using generalized linear models with fish species richness, total and guilds as the dependent variable and estimates of buffered landscape areas as explanatory variables. Our analysis identified the significance of landscape variables in determining the diversity of fish assemblages in Amazonian floodplain lakes. Spatial scale was also identified as a significant determinant of fish diversity as landscape effects were more evident at larger spatial scales. In particular, (1) total species richness was more sensitive to variations in the landscape areas than number of species within guilds and (2) the spatial extent of the wetland class of shrubs was consistently the more influential on fish species diversity.

scholarly journals Complex community responses underpin biodiversity change following invasion

2021 ◽  
Author(s):  
Alessandra R. Kortz ◽  
Anne E. Magurran
Keyword(s):  
Invasive Species ◽  
Species Richness ◽  
Spatial Scales ◽  
Species Abundance ◽  
Ecological Systems ◽  
Multi Scale ◽  
Mechanistic Approach ◽  
Α Diversity ◽  
Biodiversity Change ◽  
Insight Into

AbstractHow do invasive species change native biodiversity? One reason why this long-standing question remains challenging to answer could be because the main focus of the invasion literature has been on shifts in species richness (a measure of α-diversity). As the underlying components of community structure—intraspecific aggregation, interspecific density and the species abundance distribution (SAD)—are potentially impacted in different ways during invasion, trends in species richness provide only limited insight into the mechanisms leading to biodiversity change. In addition, these impacts can be manifested in distinct ways at different spatial scales. Here we take advantage of the new Measurement of Biodiversity (MoB) framework to reanalyse data collected in an invasion front in the Brazilian Cerrado biodiversity hotspot. We show that, by using the MoB multi-scale approach, we are able to link reductions in species richness in invaded sites to restructuring in the SAD. This restructuring takes the form of lower evenness in sites invaded by pines relative to sites without pines. Shifts in aggregation also occur. There is a clear signature of spatial scale in biodiversity change linked to the presence of an invasive species. These results demonstrate how the MoB approach can play an important role in helping invasion ecologists, field biologists and conservation managers move towards a more mechanistic approach to detecting and interpreting changes in ecological systems following invasion.

Sign in / Sign up

Export Citation Format

Share Document