Depth of edge influence of the agricultural-forest landscape boundary, Southwestern China

Species-specific variations in wing morphology and echolocation call characteristics often define which of three structural habitat types (open, cluttered, and edge) different bat species most frequently and efficiently use for foraging. Although edges are recognized as important habitats for commuting and foraging bats, no study to date has examined the depth of edge influence (DEI), the extent of quantitative changes in activity with distance from an edge, for any bat species. We focused our study on five species: northern long-eared bat, Myotis septentrionalis (Trouessart, 1897); hoary bat, Lasiurus cinereus (Beauvois, 1796); little brown bat, Myotis lucifugus (LeConte, 1831); silver-haired bat, Lasionycteris noctivagans (LeConte, 1831); big brown bat, Eptesicus fuscus (Beauvois, 1796). We predicted DEI would vary with species-specific differences in wing morphology and echolocation call characteristics. From June to August in 2010 and 2011, we passively recorded echolocation calls three to four times per month at eight sites in eastern Ontario, Canada. We found that species’ activity was highest at the edge, regardless of wing morphology and echolocation call characteristics. The DEI for all species was approximately 40 m into both forests and fields. Understanding the effects of DEI on bats will enable more effective acoustic monitoring in future studies and may provide crucial information for management decisions.

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Trophic level and edge history modulate the depth of edge influence

ARPHA Conference Abstracts ◽

10.3897/aca.2.e37132 ◽

2019 ◽

Vol 2 ◽

Author(s):

Tibor Magura ◽

Bela Tóthmérész

Keyword(s):

Edge Effect ◽

Trophic Level ◽

Ground Beetle ◽

Ground Beetles ◽

Optimal Size ◽

Natural Habitats ◽

Predator Species ◽

Depth Of Edge Influence ◽

The Impact ◽

Edge Influence

Habitat edges are increasingly important worldwide because of forest fragmentation and the loss of natural habitats. Reduction in habitat area, increased isolation of fragments are considered to be the primary cause of species decline and extinction in fragmented landscapes. Edge effect is a key determinant, since most effects of fragmentation attributed to patch area may be scaled-up edge effect. Moreover, the isolation of patches is basically determined by the filter function (permeability) of edges. The distance that edge effects extend into the adjacent core (interior) habitat (the depth of edge influence, DEI) is a central issue in edge studies, as it fundamentally influences environmental properties, composition and structure of core habitats, all which significantly control species occurrences. Most previous studies on DEI neglected the impact of origin and the processes maintaining edges, although the structural and functional properties of edges determined by their history may modulate the permeability of edges, and consequently DEI. Evaluating available information on ground beetles (Coleoptera: Carabidae) in forest edges, we show that both species traits and edge history affect DEI on ground beetles. We found that DEI on abundance of herbivore, omnivore and predator ground beetle species is similar in natural edges, and edges maintained by agriculture, while it is generally penetrated over greater distances into the forests across edges repeatedly disturbed by forestry or other anthropogenic interventions than across edges maintained by natural processes. We found extreme edge effect across edges under forestry activities, as DEI on abundance of predator species is penetrated into the forest interiors up to ≤ 300 m. According to our findings DEI is more pronounced for predators and across edges created and maintained by forestry operations, suggesting outstanding sensitivity of higher trophic level organisms to fragmentation caused by forestry activities. Our result suggests that in planning the optimal size and shape of fragments for ecosystem-based forest management, to provide a core zone, a minimum area of 50 ha of circular forest fragments is required for maintaining an intact ground beetle assemblage.

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Effects of habitat fragmentation: increased isolation and reduced habitat size reduces the incidence of dead wood fungi beetles in a fragmented forest landscape

Ecography ◽

10.1034/j.1600-0587.2000.230411.x ◽

2000 ◽

Vol 23 (4) ◽

pp. 492-502 ◽

Cited By ~ 9

Author(s):

Bjorn Arne Rukke

Keyword(s):

Habitat Fragmentation ◽

Dead Wood ◽

Forest Landscape ◽

Habitat Size ◽

Fragmented Forest

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Reconstruction of maximum temperature on Zhegu Mountain, western Sichuan Plateau (China)

Climate Research ◽

10.3354/cr01606 ◽

2020 ◽

Vol 81 ◽

pp. 1-14

Author(s):

M Keyimu ◽

Z Li ◽

Y Zhao ◽

Y Dong ◽

B Fu ◽

...

Keyword(s):

Tree Growth ◽

Ring Width ◽

Volcanic Eruptions ◽

Southwestern China ◽

Maximum Temperature ◽

Driving Mechanism ◽

Western Sichuan ◽

Relationship Analysis ◽

Decadal Scale ◽

Thermal Variability

Historical temperature reconstructions at high altitudes are still insufficient in southwestern China, which is considered one of the most sensitive areas to climate change in the world. Here we developed a tree ring-width chronology of Faxon fir Abies fargesii var. faxoniana at the upper timber line on Zhegu Mountain, Miyaluo Scenic Area, western Sichuan, China. The climate-tree growth relationship analysis indicated temperature as the dominant regulator on radial tree growth in this region. The reconstruction of aggregated maximum temperature (TMX) of autumn and winter for the period 1856-2016 was achieved with a linear regression model that accounted for 43.6% of the actual variability in the common time series (1954-2016). The reconstruction identified 4 warm periods and 3 cold periods. Similarities of warm and cold periods with previously published reconstructions from nearby sites indicated the reliability of our reconstruction. The significant positive correlation between TMX reconstruction and the Asian-Pacific Oscillation index and the Atlantic Multi-decadal Oscillation index suggested a linkage between large-scale climate circulations and the thermal variability at a multi-decadal scale on the western Sichuan Plateau. We also found that solar activity exerted a strong influence on decadal temperature variability in this region. The cold periods were matched well with historical large volcanic eruptions. Our results strengthen the historical climatic information in southwestern China and contribute to further understanding the regional thermal variability as well as its driving mechanism.

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