Depth Of Edge Influence Research Articles

Effects of habitat edges on vegetation structure and the vulnerable golden-brown mouse lemur (Microcebus ravelobensis) in northwestern Madagascar

BackgroundEdge effects can influence species composition and community structure as a result of changes in microenvironment and edaphic variables. We investigated effects of habitat edges on vegetation structure, abundance and body mass of one vulnerable Microcebus species in northwestern Madagascar. We trapped mouse lemurs along four 1000-m transects (total of 2424 trap nights) that ran perpendicular to the forest edge. We installed 16 pairs of 20 m2 vegetation plots along each transect and measured nine vegetation parameters. To determine the responses of the vegetation and animals to an increasing distance to the edge, we tested the fit of four alternative mathematical functions (linear, power, logistic and unimodal) to the data and derived the depth of edge influence (DEI) for all parameters.ResultsLogistic and unimodal functions best explained edge responses of vegetation parameters, and the logistic function performed best for abundance and body mass of M. ravelobensis. The DEI varied between 50 m (no. of seedlings, no. of liana, dbh of large trees [dbh ≥ 10 cm]) and 460 m (tree height of large trees) for the vegetation parameters, whereas it was 340 m for M. ravelobensis abundance and 390 m for body mass, corresponding best to the DEI of small tree [dbh < 10 cm] density (360 m). Small trees were significantly taller and the density of seedlings was higher in the interior than in the edge habitat. However, there was no significant difference in M. ravelobensis abundance and body mass between interior and edge habitats, suggesting that M. ravelobensis did not show a strong edge response in the study region. Finally, regression analyses revealed three negative (species abundance and three vegetation parameters) and two positive relationships (body mass and two vegetation parameters), suggesting an impact of vegetation structure on M. ravelobensis which may be partly independent of edge effects.ConclusionsA comparison of our results with previous findings reveals that edge effects are variable in space in a small nocturnal primate from Madagascar. Such an ecological plasticity could be extremely relevant for mitigating species responses to habitat loss and anthropogenic disturbances.

Trophic level and edge history modulate the depth of 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.

Spatial patterns and edge effects on soil organic matter and nutrients in a forest fragment of southern Brazil

The discrimination between edge effects and spatial patterns of the availability of soil nutrients exerts a great influence on measures of forest productivity and the global carbon pool. We sampled a regular grid with infill points of topsoil in a 13-ha Atlantic forest fragment and surrounding grassland in southern Brazil, and tested the influence of the underlying spatial nutrient availability and edge effects on this pattern using Generalised Additive Models. Soil phosphorus was controlled by vegetation type. Magnesium and potassium were controlled by parent material and pedogenesis, whereas calcium and soil organic matter were influenced by both processes. The depth of edge influence was estimated at 50m inside the forest and at 25m distance from the forest edge in the grassland. These continuous estimates of forest–grassland edge effects in soil nutrient availability may play a major role in determining global ecosystem functioning, as forests and landscapes become even more fragmented.

여름철 공원 수림지 가장자리의 온열환경 기울기 변화 - 하동송림과 함양상림을 대상으로 -

This study investigated the extent and magnitude of the woodland edge effects on users` thermal environments according to distance from woodland border. A series of experiments to measure air temperature, relative humidity, wind velocity, MRT and UTCI were conducted over six days between July 31 and August 5, 2015, which corresponded with extremely hot weather, at the south-facing edge of Hadongsongrim(pure Pinus densiflora stands, tree age: , tree height: , canopy closure: 75%, N , E , elevation 7~10m) and east-facing edge of Hamyangsangrim (Quercus serrata-Carpinus tschonoskii community, tree age: 102~125yr/58~123yr, tree height: tree layer layer layer , herbaceous layer coverage ratio 60%, canopy closure: 96%, N , E , elevation 170~180m) in rural villages of Hadong and Hamyang, Korea. The minus result value of depth means woodland`s outside. The depth of edge influence(DEI) on the maximum air temperature, minimum relative humidity and wind speed at maximum air temperature time during the daytime(10:00~17:00) were detected to be , and , respectively, in the mature evergreen conifer woodland of Hadongsongrim. These were detected to be , and , respectively, in the deciduous broadleaf woodland of Hamyansangrim. The DEI on the maximum 10 minutes average MRT, UTCI from the three-dimensional environment absorbed by the human-biometeorological reference person during the daytime(10:00~17:00) were detected to be and , respectively, in the relatively sparse woodland of Hadongsongrim. These were detected to be and , respectively, in the dense and closed woodland of Hadongsongrim. Edge effects on the thermal environments of air temperature, relative humidity, wind speed, MRT and UTCI in the sparse woodland of Hadongsongrim were less pronounced than those recorded in densed and closed woodland of Hamyansangrim. The gradient variation was less steep for maximum 10 minutes average UTCI with at least (Hadongsongrim) and (Hamyansangrim) being required to stabilize the UTCI at mature woodlands. Therefore it is suggested that the woodlands buffer widths based on the UTCI values should be 3.5~7.6 m(Hamyansangrim) and 4.3~8.9(Hadongsongrim) m on each side of mature woodlands for users` thermal comfort environments. The woodland edge structure should be multi-layered canopies and closed edge for the buffer effect of woodland edge on woodland users` thermal comfort.

Landscape-Scale Implications of the Edge Effect on Soil Fauna Activity in a Temperate Forest

Although studies on edge effects on species richness and abundance are numerous, the responses of ecosystem processes to these effects have received considerably less attention. How ecosystem processes respond to edge effects is particularly important in temperate forests, where small fragments and edge habitats form a considerable proportion of the total forest area. Soil fauna are key contributors to decomposition and soil biogeochemical cycling processes. Using the bait lamina technique, we quantified soil fauna feeding activity, and its dependence on soil moisture and distance to the edge in a broad-leaved forest in Southern England. Feeding activity was 40% lower at the forest edge than in the interior, and the depth of edge influence was approximately 75 m. A watering treatment showed that moisture limitation was the main driver of the reduced feeding activity at the edge. In England, only 33% of the forest area is greater than 75 m from the edge. Therefore, assuming that the results from this single-site study are representative for the landscape, it implies that only one- third of the forest area in England supports activity levels typical for the forest core, and that edge effects reduce the mean feeding activity across the landscape by 17% (with lower and upper 90% confidence intervals of 1.3 and 23%, respectively). Changing climatic conditions, such as summer droughts may exacerbate such effects as edges lose water faster than the forest interior. The results highlight the importance of taking edge effects into account in ecological studies and forest management planning in highly fragmented landscapes.

Effects of timber harvests and silvicultural edges on terrestrial salamanders.

Balancing timber production and conservation in forest management requires an understanding of how timber harvests affect wildlife species. Terrestrial salamanders are useful indicators of mature forest ecosystem health due to their importance to ecosystem processes and sensitivity to environmental change. However, the effects of timber harvests on salamanders, though often researched, are still not well understood. To further this understanding, we used artificial cover objects to monitor the relative abundance of terrestrial salamanders for two seasons (fall and spring) pre-harvest and five seasons post-harvest in six forest management treatments, and for three seasons post-harvest across the edge gradients of six recent clearcuts. In total, we recorded 19,048 encounters representing nine species of salamanders. We observed declines in mean encounters of eastern red-backed salamanders (Plethodon cinereus) and northern slimy salamanders (P. glutinosus) from pre- to post-harvest in group selection cuts and in clearcuts. However, we found no evidence of salamander declines at shelterwoods and forested sites adjacent to harvests. Edge effects induced by recent clearcuts influenced salamanders for approximately 20 m into the forest, but edge influence varied by slope orientation. Temperature, soil moisture, and canopy cover were all correlated with salamander counts. Our results suggest silvicultural techniques that remove the forest canopy negatively affect salamander relative abundance on the local scale during the years immediately following harvest, and that the depth of edge influence of clearcuts on terrestrial salamanders is relatively shallow (<20 m). Small harvests (<4 ha) and techniques that leave the forest canopy intact may be compatible with maintaining terrestrial salamander populations across a forested landscape. Our results demonstrate the importance of examining species-specific responses and monitoring salamanders across multiple seasons and years. Long-term monitoring will be necessary to understand the full impacts of forest management on terrestrial salamanders.

English

This study investigated two transition zones (matrix-forest edge-interior gradient) associated to forest fragments with different degrees of intervention, in an Andean paramo ecosystem located in Purac&eacute; National Park (Colombia). The relationship between the structures of vegetation and the spatial dynamics associated with microclimatic variation in each patch of woodland was determined in order to establish the Depth of Edge Influence (DEI). In each fragment, the vegetation was evaluated using transects of 80 x 2 m perpendicular to the margin, corresponding to 30 m of the matrix and 50 m into the woodland. All woody plants were identified, the heights and dominance was the most relevant features to determining the structure of the forest edge. Microclimatic data (humidity, sunlight exposure, air and soil temperature) were measured in transects and mapped using interpolation for determining the spatial dynamics in each gradient and the behavior of the variables associated with the DEI. The results obtained indicate that the change of microclimatic variables was significant in the margin-forest edge-interior gradient when comparing the forest fragments. The differences are related to the degree of human intervention, since the pressure exerted on certain plant species determined the spatial arrangement of these plants in the gradient. On mapping the dynamics of the microclimatic variables and their relationship to the distance in the gradient, a depth of edge influence was identified of 10 m for the fragment with less intervention (Woodland 2) and 20 m for the one with most intervention (Woodland 1). &nbsp; Key words: Paramo, ecotone, edge effect, gradient, microclimate.

Seasonal Variability in Soil Inorganic Nitrogen Across Borders Between Woodland and Farmland in the Songnen Plain of Northeast China

To study the seasonal variability of soil inorganic nitrogen (N) across borders at the woodland-farmland ecotone and potential mechanisms, contents of soil inorganic N were measured during the dry season (May 20 and June 30) and the rainy season (August 10 and September 20) of 2006 in the Songnen Plain of Northeast China. The borders between farmland and woodland were determined by a border-and-ecotone detection analysis (BEDA). The ecotone limits, often referred to as the depth-of-edge influence (DEI), are critical for determining the scale at which edge effect operates. The results showed that the soil inorganic N border between the woodland and farmland was located further toward the woodland interior during the rainy season (DEI = 53.4 ± 8.7 m, August 10) than during the dry season (DEI = 35.0 ± 12.6 m, May 20). The seasonal variability in the soil inorganic N border was found to be associated with seasonal changes of deposition flux of N (the correlation coefficients between them for the dry season and rainy season were 0.61 and 0.67, respectively), which resulted from foliation patterns of trees and crops. Accordingly, the leaf area index at woodland edges was lower than that in the woodland interior, so woodland edges captured large amounts of atmosphere nitrogen deposition. The average DEI was 44.1 m, which was in accordance with the values of other temperate forest boundaries in literatures; therefore, BEDA was an appropriate method to estimate the borders of ecotones.

The depth of edge influence among insectivorous bats at forest–field interfaces

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.

Predicting the impacts of edge effects in fragmented habitats: Laurance and Yensen’s core area model revisited

An accurate estimate of the impact of edge effects is essential for the conservation management of threatened species in isolated habitat fragments. In a seminal paper, Laurance and Yensen (1991) developed the first generalized predictive model estimating the amount of edge-affected area and remaining unmodified core area in isolated fragments. Despite their conclusion that the core-area model should be applicable to all fragments, regardless of size or shape, the model has never been validated beyond the limited range of parameters under which the model was constructed. Here, we conduct a sensitivity test of the core-area model accounting for ecologically-realistic variation in fragment Shape Index (SI), and collinearity among shape, area and depth of edge influence (DEI). Using well-resolved GIS data for the South Island of New Zealand, we find substantial core-area model underestimates for large fragments (>10,000ha) with high SI values (>10.0), particularly at high DEI (>100m). To overcome this we reformulate the core-area model with a more accurate shape-specific exponent function, and test our new model against Laurance and Yensen’s core-area model and a null geometric model using an independently-derived GIS dataset for the North Island, New Zealand. Our new model provides a significantly better fit to the data. We conclude that past predictive applications of the core-area model have underestimated true core area, and we recommend our simple re-formulated model for estimating the degree of population and community responses to habitat fragmentation under ecologically-realistic scenarios of high patch shape complexity and large spatial extent of edge influence.

Edge effects on ground beetles at the woodlot-field interface are short-range and asymmetrical

Boundaries between woodlots and agricultural habitats are numerous in temperate agricultural landscapes and influence ecological processes in both woodlots and agricultural habitats. 2 We aimed to determine how far the species assemblage of ground beetles in woodlot and open habitats was influenced by the presence of the woodlot-field boundary. 3 We studied the distribution of ground beetles on both sides of the boundaries of four woodlots along transects of pitfall traps (n = 140). The depth of edge influence (i.e. the distance from the boundary at which the presence of the boundary has no more significant influence) on the species assemblage of ground beetles in each woodlot and in each agricultural habitat was determined with nonlinear canonical analysis of principal coordinates, an ordination method that is followed by nonlinear regression of the principal coordinates on distance from the boundary. 4 The depth of edge influence on the species assemblages of ground beetles was asymmetrical relative to the boundary: it was generally higher and had higher variability in open habitats (14.4 ± 12.3 m) than in woodlots (4.9 ± 2.3 m). Species assemblages of ground beetles in edges were a mix between both adjacent species assemblages. Edge effects in woodlots were deeper in the woodlots exhibiting a deeper penetration of open habitat species. Symmetrically, edge effects in open habitat were deeper in the open habitats with a deeper diffusion of forest species into the open habitat. 5 Forest ground beetles were not threatened by edge effects. Rather, edge effects are likely to benefit agriculture, mostly through the dispersal of predatory forest species into agricultural fields.

Edge effects on fire spread in a disturbed Northern Wisconsin landscape

The effect of area-of-edge influence (AEI) on fire size and movement was simulated by considering the distribution of single and multiple edges in the Chequamegon-Nicolet National Forest in Northern Wisconsin, USA. Six hypothetical landscapes with different delineations of AEIs were created for simulating fire spread using FARSITE to evaluate the influence of edges on the rate and direction of fire spread. The burned area differed significantly among the six landscapes. In the three scenarios with buffered edges, the burned area increased by 35% with high loading fuel in AEIs, while it decreased by 21 and 46% with medium and low fuel loading in the AEIs, respectively, as compared to the no edge scenario. In two scenarios we delineated the area-of-multiple-edge influence (AMEI) and placed more than one high loading fuel within it. This increased the burned area by 5% from the high buffered edge scenario and by 40% from the control. When the depth-of-edge influence (DEI) was doubled to 60 m using AMEI with high fuels, the burned area increased by 20% from the high buffered edge scenario and by 60% from the control. We found that low and medium fuel loading slowed the fire spread and over time, caused the fire front to change direction. In high fuel loading scenarios, AEIs acted as corridors facilitating the fire spread by providing a contiguous patch of fuel which allowed fires to increase in size and pulled the fire front in the same direction.

Core area analysis at semi-deciduous forest islands in the Comoé National Park, NE Ivory Coast

For the protection of forest-interior species in both natural forest islands and anthropogenic forest fragments knowledge on the size of forest-core areas is a central issue. In an intact mosaic of semi-deciduous forests and savanna in the Comoe National Park 31 forest islands were selected (2.1–146.1 ha). Values for the depth-of-edge influence (DEI) of the study area recently published range from 0 m up to nearly 150 m. Thus, core-area analysis was carried out for this range in 5 m steps. For a DEI of 55 m—e.g. computed for tree-species composition of large trees—half of the total forest area can be considered as core area, but only 9 of the studied forest islands still contained a relative core area (rCA) of more than 50%. From non-linear regression it was estimated that for a DEI of 55 m an rCA of 50% can be expected for forest islands with a size of 36.6 ± 7.6 ha. This value increased exponentially with increasing DEI. The GIS-based core-area analysis presented in this paper proved to be suitable to give a well interpretable overview on rCA with respect to varying DEI, and we recommend to incorporate this type of analysis in existing GIS-tools. As the presented study is the first sound core area analysis at forest islands in West Africa, data contribute to a better understanding of this field of ecology that is of high relevance for planners and decision makers to protect biodiversity.

Detection of seasonal variability in microclimatic borders and ecotones between forest and savanna

Abstract Along eight forest-savanna transects, the borders, the width of associated ecotones, and the depth-of-edge influence (DEI) towards the forest interior were determined on the basis of microclimatic parameters. The analysis focused on the seasonal variability of microclimate at the forest-savanna ecotone that has so far rarely been investigated. The study was located in an intact mosaic of semi-deciduous forests and savanna in the Comoe National Park (north-eastern Ivory Coast). The microclimatic parameters air temperature, air humidity, and vapor pressure deficit were measured from the dry season (February) until the rainy season (September) during five measurement periods (MP). Borders and ecotones including their confidence intervals were determined by a border-and-ecotone detection analysis, which is based on non-linear regression analysis. The ecotone limits were interpreted as DEI towards the two habitats. During the dry season, the microclimatic border between forest and savanna was located further towards the forest interior than during the rainy season. This may be caused by different foliation patterns of tree species at the forest interior and the forest boundary, with the latter being completely defoliated during the dry season. In addition, the variability of microclimatic parameters was higher and differences between forest and savanna were less pronounced during the dry season. The minimum DEI towards the forest interior was 27.4±15.5 m for air humidity in the rainy season (MP-5). The maximum DEI of 137.3 ±138.3 m occurred for air temperature in the dry season (MP-1). The average DEI for all microclimate parameters and MPs was 50.5 m. These DEI values are similar to observations from temperate and tropical forest boundaries in the literature. As microclimate borders proved to shift over the seasons, detailed knowledge of species’ responses to this variability appears to be essential for predicting concomitant dynamics of forest core areas.

Areas influenced by multiple edges and their implications in fragmented landscapes

We introduced a new approach for delineating areas of multiple edge influence (AMEI) within a fragmented landscape using a geographic information system (GIS). AMEI was defined as the interface that is affected by more than two neighboring patch types. We decomposed AMEI into three components: AMEI 1, the area where one patch type meets a different patch type; AMEI 2, the area where one patch type meets two different patch types; AMEI 3, the area where one patch type meets three or more other different patch types. This approach provides a direct measure of the complexities of multiple edge effects that may occur at a spatial location, and also measures the amount of the affected area at the patch and landscape levels. Using the Chequamegon National Forest (CNF), USA, as a case study, we found that the total AMEI was approximately 48, 74, 86, and 92% of the landscape with depth of edge influence (DEI) at 30, 60, 90, and 120 m, respectively. The more complicated components of the area of multiple edge influence (AMEI 2 and AMEI 3) ranged from 5% (at 30 m DEI) to 60% (at 120 m DEI) of the studied landscape. Most empirical and modeling studies miss this additional edge complexity if they only consider a single edge structure. In general, AMEI 1 is greater than AMEI 2; AMEI 2 is greater than AMEI 3. Three indices – AMEI to patch area ratio (APAR), AMEI to patch edge area ratio (APEAR), and AMEI to landscape area ratio (ALAR) – were introduced to explain the relative importance of AMEI at the edge, patch, and landscape levels. This approach has the potential to improve model predictions and better inform us about ecological processes that are influenced by multiple edge effects at patch and landscape scales.

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

AbstractThe landscape boundary is an important component of a landscape and often plays an indispensable role in regulating ecological flows. The primary objective of this study was to estimate how far the edge effects on agricultural‐forest landscape boundaries can penetrate into the forest and agricultural field. This will serve as a basis for understanding the interaction between forest and agricultural fields in the mountainous area of southwestern China and provide scientific basis for the practice of the policy of “returning agricultural field to forest.” Based on field investigations, three types of boundaries with six sampling transects were selected. We investigated the soil moisture, soil nutrients and vegetation diversity along the transect gradient and explored the depth of edge influence (DEI) with moving split‐window techniques for analyzing the data. DEI for soil moisture changed with the seasons, ranging from 6 m in the pepper field to 2 m in the forest during the dry season, and from 12 m in the pepper field to 2 m in the forest after heavy rain. DEI based on soil organic matter ranged from 1.5 to 10 m in the forest field, while it was not detected based on other soil nutrient factors. DEI based on vegetation diversity varied from 4 to 26 m and from 10 to 31 m in the forest and agricultural fields, respectively. These results provide the scientific basis for the policy “returning agricultural field to forest”. Based on these field observations, reducing human disturbance and revegetating with natural shrubs and meadows could be more effective for vegetation conservation in terms of soil moisture and soil nutrient content in the arid valley of the Minjiang River.

Comparison of two approaches for detecting the depth of edge influence on vegetation diversity in the arid valley of southwestern China

Three types of landscape boundary (forest/pepper field, forest/cabbage field, and forest/grassland) were selected in the arid valley of upper reaches of Minjiang River, southwestern China. On the basis of vegetation diversity, the depth of edge influence (DEI) on different types of landscape boundaries was estimated using principal components analysis (PCA) method and moving split-window techniques (MSWT). The results showed that in the 5 transects, PCA method was able to detect the edge influence depth with 3 transects, while MSWT could explain 4 transects. It is concluded that PCA and MSWT both can be used to detect the depth of edge influence within 50 m from the edge to the interior. Similar conclusions were drawn in the forest of each transect with the two methods, but no similar conclusions were drawn in the pepper field of each transect. Although the two methods have advantages and disadvantages respectively, they are useful tools for characterizing edge dynamics. Comparing the two methods, MSWT is more successful.

Vegetation responses to natural and salvage logged fire edges in Douglas-fir/hardwood forests

Natural edges created by fire are a common component of forest ecosystems with moderate-severity fire regimes and will continue to be important as the frequency of extreme fire events increases due to historical fire suppression throughout North America. The effect of high-severity fires, with and without salvage logging, on adjacent intact forest patches has not been studied. Fourteen years after a wildfire, we examined the structure and composition of vegetation along the gradient from burned stands into the adjacent forest interior at three salvage logged edges and three unsalvaged edges in Douglas-fir/hardwood forests of northwestern California. Natural, unsalvaged edges were characterized by an increase of native, ruderal species, rather than a reduction of forest interior species. Only two forest interior species reacted negatively to the edge environment, both at salvaged edges. Old-growth community types, identified by two-way indicator species analysis (TWINSPAN), occurred 30 m closer to the edge at unsalvaged sites, compared to salvaged sites. Twenty commonly observed species (>10% frequency) demonstrated significant responses to the edge environment; 11 species had a larger depth of edge influence (DEI) at salvaged edges, three had a larger DEI at unsalvaged edges, and six had an equal DEI. Our results suggest that, compared to unsalvaged stands, the removal of snags and subsequent broadcast burning of salvaged logged stands significantly altered plant composition and structure of the edge environment. By increasing the patch contrast between burned and intact forest stands, salvage logging increased the depth of edge influence of fire-created edges by 15–30 m.

Border and ecotone detection by vegetation composition along forest‐savanna transects in Ivory Coast

Abstract. Question: How do properties of different vegetation components vary along ecotones of semi‐deciduous forest islands, and can the depth of edge influence (DEI) of the components be detected using a novel combination of analyses?Location: Comoé National Park (CNP), NE Ivory Coast.Methods: Along eight transects at semi‐deciduous forest islands tree individuals &gt; 20 cm DBH were mapped. At one transect, tree and shrub individuals down to 1 cm DBH were measured and cover of species was estimated. Split moving window dissimilarity analysis (SMWDA) and moving window regression analysis (MWRA) were combined to detect statistical significance of borders in multivariate vegetation data along continuous transects, to determine the width of associated ecotones, and, thus, the DEI towards the forest interior.Results: For trees &gt; 20 cm DBH, a distinct boundary formation was detected, dominated by the semi‐fire resistant tree species Anogeissus leiocarpus. The median of DEI towards the forest interior was 55 m. Ecotone detection with all species present revealed an interlocked sequence of ecotones for grasses, herbs, woody climbers, shrubs and trees, with each of these ecotones being narrower than the overall ecotone. DEI ranged from 10 m for grasses up to 120 m for trees and shrubs.Conclusions: The coherent set of analyses applied proved to be an objective method for detecting borders and the width of associated ecotones. The patterns found may be explained by successional processes at the forest‐savanna border. The DEI measured for the forest islands in the nearly undisturbed semi‐natural system of the CNP is of relevance to concepts of core‐area analysis and the protection of forest interior species in semi‐deciduous forests in tropical West Africa.

Border and ecotone detection by vegetation composition along forest-savanna transects in Ivory Coast

Abstract Question: How do properties of different vegetation components vary along ecotones of semi-deciduous forest islands, and can the depth of edge influence (DEI) of the components be detected using a novel combination of analyses? Location: Comoe National Park (CNP), NE Ivory Coast. Methods: Along eight transects at semi-deciduous forest islands tree individuals > 20 cm DBH were mapped. At one transect, tree and shrub individuals down to 1 cm DBH were measured and cover of species was estimated. Split moving window dissimilarity analysis (SMWDA) and moving window regression analysis (MWRA) were combined to detect statistical significance of borders in multivariate vegetation data along continuous transects, to determine the width of associated ecotones, and, thus, the DEI towards the forest interior. Results: For trees > 20 cm DBH, a distinct boundary formation was detected, dominated by the semi-fire resistant tree species Anogeissus leiocarpus. The median of DEI towards the forest interior was 55 ...