Vegetation Structural Complexity Research Articles

Habitat Suitability for Small Mammals in Mediterranean Landscapes: How and Why Shrubs Matter

Fires are usually seen as a threat for biodiversity conservation in the Mediterranean, but natural afforestation after abandonment of traditional land uses is leading to the disappearance of open spaces that benefit many species of conservation interest. Fires create open habitats in which small mammals can live under more favourable conditions, such as lower predation, interspecific competition, and higher food availability. We analysed the role of changes in shrub cover and shrub preference by small mammals along the Mediterranean post-fire succession. We used data (period 2008–2018) from 17 plots woodlands and post-fire shrublands present in the study area (Barcelona’s Natural Parks, Catalonia, NE Spain), and vegetation structure was assessed by LiDAR technology for modelling ground-dwelling small mammal preferences. The diversity, abundance, and stability of Mediterranean small mammal communities negatively responded to vegetation structural complexity, which resulted from the combined effects of land abandonment and recovery after wildfires. We suggest that biotic factors such as vegetation profiles (providing food and shelter) and their interaction with predators and competitors could be responsible for the observed patterns. Considering the keystone role of small mammals in the sustainability of Mediterranean forest, our results could be useful for management under the current global change conditions.

Estimating density of terrestrial reptiles in forest habitats: The importance of considering availability in distance sampling protocols

Reptile populations are relevant components of biodiversity in both temperate and tropical forests. However, in forest habitats reptiles are secretive and the complex structure of the environment makes it difficult to assess with confidence their abundance and density. In general, capture-mark-recapture (CMR) or distance sampling (DS) are used to estimate demographic parameters of reptiles in these complex habitats. CMR may be expensive in terms of time, materials and sampling effort, while DS is strongly biased when animals lying on the transect line are overlooked. In this study, we applied a combination of CMR and hierarchical distance sampling (HDS) to estimate the density of the Common Wall Lizard (Podarcis muralis), a widespread Mediterranean terrestrial reptile. We randomly placed linear transects in a deciduous woodland (i.e. Castanea sativa), in a coniferous plantation forest (Pinus nigra) and in a dry prairie habitat, and we applied a hierarchical mark-recapture distance sampling (HMRDS) protocol. Density estimates were similar between the deciduous woodland (47 individuals/ha) and the dry prairie habitat (44 individuals/ha), while markedly lower in the coniferous plantation forest (13 individuals/ha). HMRDS data, analyzed in a Bayesian framework, showed the importance of correcting for the assumption of complete detection on the transect line, in all the three habitat types. Therefore, our approach should be useful when assessing the density of small and cryptic terrestrial animals, not only in forest but also in habitat with an apparently less complex vegetation structure.

Comparisons of the composition of spider assemblages in three vegetation habitats in Bogor, West Java, Indonesia

Abstract. Lia M, Rauf A, Hindayana D. 2021. Comparisons of the composition of spider assemblages in three vegetation habitats in Bogor, West Java, Indonesia. Biodiversitas 23: 244-255. Vegetation structures are known to influence the microclimate and consequently the invertebrate assemblages. This study, therefore, aims to compare the species composition of assemblages of ground- and foliage-dwelling spiders in three vegetation habitats: undisturbed urban forest, oil palm plantation, and cornfield, in Bogor, West Java. To ensure a thorough representation of all spider guilds, spiders were collected using pitfall traps, sweep net, and through a direct search on ground and vegetation from January to July 2016. A total of 2299 individual spiders, representing 28 families and 207 species/morphospecies were collected. The spider species richness, abundance, and diversity were higher in the forest and oil palm plantation, compared to the cornfield. Furthermore, the dominant guild in the forest habitat was orb weavers, while the oil palm and corn habitats were dominated by ground runners. The non-metric multidimensional scaling exhibited that the composition of spider assemblages varied among the three vegetation habitats, with spider assemblages in forest habitat associated with higher RH, while the corn habitat was correlated with high light intensity and air temperature. The indicator species analysis revealed that Tetragnathidae has high potential as indicators of the dense, complex vegetation structure of the forest, while Lycosidae is indicators of the more open vegetation of oil palm plantation and cornfield habitats.

Using Airborne Laser Scanning to Characterize Land-Use Systems in a Tropical Landscape Based on Vegetation Structural Metrics

Many Indonesian forests have been cleared and replaced by fast-growing cash crops (e.g., oil palm and rubber plantations), altering the vegetation structure of entire regions. Complex vegetation structure provides habitat niches to a large number of native species. Airborne laser scanning (ALS) can provide detailed three-dimensional information on vegetation structure. Here, we investigate the potential of ALS metrics to highlight differences across a gradient of land-use management intensities in Sumatra, Indonesia. We focused on tropical rainforests, jungle rubber, rubber plantations, oil palm plantations and transitional lands. Twenty-two ALS metrics were extracted from 183 plots. Analysis included a principal component analysis (PCA), analysis of variance (ANOVAs) and random forest (RF) characterization of the land use/land cover (LULC). Results from the PCA indicated that a greater number of canopy gaps are associated with oil palm plantations, while a taller stand height and higher vegetation structural metrics were linked with rainforest and jungle rubber. A clear separation in metrics performance between forest (including rainforest and jungle rubber) and oil palm was evident from the metrics pairwise comparison, with rubber plantations and transitional land behaving similar to forests (rainforest and jungle rubber) and oil palm plantations, according to different metrics. Lastly, two RF models were carried out: one using all five land uses (5LU), and one using four, merging jungle rubber with rainforest (4LU). The 5LU model resulted in a lower overall accuracy (51.1%) due to mismatches between jungle rubber and forest, while the 4LU model resulted in a higher accuracy (72.2%). Our results show the potential of ALS metrics to characterize different LULCs, which can be used to track changes in land use and their effect on ecosystem functioning, biodiversity and climate.

Specific Drivers and Responses to Land Surface Phenology of Different Vegetation Types in the Qinling Mountains, Central China

Land surface phenology (LSP), as a precise bio-indicator that responds to climate change, has received much attention in fields concerned with climate change and ecology. Yet, the dynamics of LSP changes in the Qinling Mountains (QMs)—A transition zone between warm-temperate and north subtropical climates with complex vegetation structure—under significant climatic environmental evolution are unclear. Here, we analyzed the spatiotemporal dynamics of LSP for different vegetation types in the QMs from 2001 to 2019 and quantified the degree of influence of meteorological factors (temperature, precipitation, and shortwave radiation), and soil (temperature and moisture), and biological factors (maximum of NDVI and middle date during the growing season) on LSP changes using random forest models. The results show that there is an advanced trend (0.15 days/year) for the start of the growing season (SOS), a delayed trend (0.24 days/year) for the end of the growing season (EOS), and an overall extended trend (0.39 days/year) for the length of the growing season (LOS) in the QMs over the past two decades. Advanced SOS and delayed EOS were the dominant patterns leading to a lengthened vegetation growing season, followed by a joint delay of SOS and EOS, and the latter was particularly common in shrub and evergreen broadleaved forests. The growth season length increased significantly in western QMs. Furthermore, we confirmed that meteorological factors are the main factors affecting the interannual variations in SOS and EOS, especially the meteorological factor of preseason mean shortwave radiation (SWP). The grass and crop are most influenced by SWP. The soil condition has, overall, a minor influence the regional LSP. This study highlighted the specificity of different vegetation growth in the QMs under warming, which should be considered in the accurate prediction of vegetation growth in the future.

A zoning-based solution for hierarchical forest patch mosaic in urban parks

Urbanization has led to the loss, fragmentation, and degradation of habitats, as well as that of biodiversity in cities. Urban parks play a key role in conserving biodiversity. Despite the advantages of complex vegetation structures for insect and bird diversity, a simple vegetation structure is favored in urban parks worldwide. The trade-off between human recreation and biodiversity conservation is challenging. Zoning strategy may be an effective countermeasure informed by the national park and natural scenic area; a zoning-based solution was introduced in this study, including preserved core zones and surrounding recreation zones. Guangyanggu Urban Forest Park was found to be advantageous for biodiversity and in terms of the feasibility of a small hierarchical forest patch (HFP) in the center of Beijing, which can serve as a model for core zones. The park had higher species richness of plants, insects, and birds than did six control sample parks. The Gleason richness indices of insect and bird species significantly correlated with the ratio of multilayered vegetation area to total sample area (r = 0.757 and 0.867 respectively; p < 0.05). The HFP mosaic model was used to develop the core zone in the urban park. Nine scenarios were defined for the HFP mosaic pattern, quantitatively delineating the typical spatial patterns of HFPs in parks. These results will improve the design and management of the current urban park paradigm. A bio-friendly park model characterized by HFP can optimize professional designing and maintenance guidelines for future urban parks.

Characterizing subcanopy structure of Mediterranean forests by terrestrial laser scanning data

Vegetation structure is one of the key factors in forest ecosystems. Especially understory structure has major implications for wildlife habitat selection, reproduction, and survival. Structural indices traditionally used to characterize understory vegetation are based on field vegetation surveys describing general features such as leaf area index (LAI), canopy cover or vegetation height, hiding much of the three-dimensional vegetation structure complexity. The application of terrestrial laser scanning (TLS) in forest ecological and management applications is becoming more effective. In this study, we use TLS data to quantify spatial attributes of forest subcanopy in four different forest strata ranging from 0.5 m to 10 m from the ground. We collected data in 12 plots of mature European beech (Fagus sylvatica L.) forests and 12 plots of mature black pine (Pinus nigra subsp. laricio Maire) forests, located in the Sila National Park, Italy. We propose a TLS-based approach to estimate a fine-scale vegetation density using the Plant Density Index (PDI) and to test the PDI at different height classes. We found a significant relationship between the PDI and the number of trees belonging to the dominant layer, using the Spearman correlation coefficient (r = 0.83, pval = 0.001). Basing on PDI values, a cluster analysis of the four subcanopy strata was carried out for deriving clusters of structurally homogeneous forest plots. Results identified three clusters in terms of the vegetation features in the horizontal height classes: the first cluster primarily includes Beech forests characterized by plots with the highest tree densities; the second one includes both Beech and Pine forests characterized by dense ground vegetation and shrubs and an intermediate tree density; the third group is represented by Pine forests with massive presence of vegetation lower strata and moderate tree density. Then, PCA allowed identifying the relationship between the considered subcanopy layers and forest plots.

Role of abandoned grasslands in the conservation of spider communities across heterogeneous mountain landscapes

In the last decades, the transformation of agriculture and the associated decline in semi-natural grasslands have been major drivers of the loss of spider diversity across Europe, in particular in mountain regions. In the early stages of forest succession, abandoned grasslands exhibit a complex vegetation structure sharing environmental conditions with both open habitats and forests. At the landscape scale, the occurrence of abandoned patches can potentially provide novel habitats and niches for ground-dwelling spiders. Here, we used two complementary methods: traditional species diversity analyses and species-habitat networks to understand how abandoned grasslands can interact with the surrounding habitat mosaic in supporting spider communities. We selected six landscapes along an elevational gradient and sampled spiders in all the major agricultural and semi-natural habitats occurring across the landscapes. At all elevations, we found a similar species richness and activity density between agricultural habitats (i.e. meadows, pastures, and crop fields) and abandoned grasslands. On the contrary, we consistently found lower species richness and activity density in forests than in all open habitats. Despite the similar diversity between open habitats, most species-habitat networks exhibited a high and constant modularity, i.e. the same species tended to occur in a specific habitat type and not in the others. Only a few species were shared between abandoned and agricultural habitats, indicating that abandoned grasslands cannot support populations of most species typical of open managed habitats. Early abandoned patches increased landscape habitat heterogeneity providing unique niches to spider species that, however, rarely occur in other habitats. The maintenance of multiple habitat types across the landscape is expected to increase the regional species pool, while the role of abandoned patches as surrogate habitat for the conservation of spider species typical of semi-natural grasslands appeared limited. Similarly, abandoned patches are not expected to help maintaining the populations of spider species occurring in agricultural habitats.

Monitoring the Structure of Regenerating Vegetation Using Drone-Based Digital Aerial Photogrammetry

Measures of vegetation structure are often key within ecological restoration monitoring programs because a change in structure is rapidly identifiable, measurements are straightforward, and structure is often a good surrogate for species composition. This paper investigates the use of drone-based digital aerial photogrammetry (DAP) for the characterization of the structure of regenerating vegetation as well as the ability to inform restoration programs through spatial arrangement assessment. We used cluster analysis on five DAP-derived metrics to classify vegetation structure into seven classes across three sites of ongoing restoration since linear disturbances in 2005, 2009, and 2014 in temperate and boreal coniferous forests in Alberta, Canada. The spatial arrangement of structure classes was assessed using land cover maps, mean patch size, and measures of local spatial association. We observed DAP heights of short-stature vegetation were consistently underestimated, but strong correlations (rs &gt; 0.75) with field height were found for juvenile trees, shrubs, and perennials. Metrics of height and canopy complexity allowed for the extraction of relatively tall and complex vegetation structures, whereas canopy cover and height variability metrics enabled the classification of the shortest vegetation structures. We found that the boreal site disturbed in 2009 had the highest cover of classes associated with complex vegetation structures. This included early regenerative (22%) and taller (13.2%) wood-like structures as well as structures representative of tall graminoid and perennial vegetation (15.3%), which also showed the highest patchiness. The developed tools provide large-scale maps of the structure, enabling the identification and assessment of vegetational patterns, which is challenging based on traditional field sampling that requires pre-defined location-based hypotheses. The approach can serve as a basis for the evaluation of specialized restoration objectives as well as objectives tailored towards processes of ecological succession, and support prioritization of future inspections and mitigation measures.

Vegetation structural complexity and biodiversity in the Great Smoky Mountains

AbstractVegetation structural complexity and biodiversity tend to be positively correlated, but understanding of this relationship is limited in part by structural metrics tending to quantify only horizontal or vertical variation, and that do not reflect internal structure. We developed new metrics for quantifying internal vegetation structural complexity using terrestrial LiDAR scanning and applied them to 12 NEON forest plots across an elevational gradient in Great Smoky Mountains National Park, USA. We asked (1) How do our newly developed structure metrics compare to traditional metrics? (2) How does forest structure vary with elevation in a high‐biodiversity, high topographic complexity region? (3) How do forest structural metrics vary in the strength of their relationships with vascular plant biodiversity? Our new measures of canopy density (Depth) and structural complexity (σDepth), and their canopy height‐normalized counterparts, were sensitive to structural variations and effectively summarized horizontal and vertical dimensions of structural complexity. Forest structure varied widely across plots spanning the elevational range of GRSM, with taller, more structurally complex forests at lower elevation. Vascular plant biodiversity was negatively correlated with elevation and more strongly positively correlated with vegetation structure variables. The strong correlations we observed between canopy structural complexity and biodiversity suggest that structural complexity metrics could be used to assay plant biodiversity over large areas in concert with airborne and spaceborne platforms.

Understory vegetation contributes to microclimatic buffering of near-surface temperatures in temperate deciduous forests

Accurately predicting microclimate is considered a high priority for understanding organismal responses to climate change at biologically relevant scales. However, approaches to developing robust microclimate datasets and understanding of the biophysical processes altering microclimatic regimes are limited. We developed and evaluated an approach for predicting microclimatic temperatures in montane forests that incorporates the influence of complex vegetation structure and landscape physiography. Additionally, we determined spatiotemporal mismatches between free-air and microclimatic temperatures to highlight the location, phenology, and magnitude of differences in predicted temperature. We combined temperature datalogger measurements with LiDAR-derived vegetation and GIS-derived landscape physiographic characteristics to downscale free-air temperatures to microclimatic (3 m2 spatial resolution) temperatures in the Great Smoky Mountains. We assessed the contribution of forest vegetation layers in altering microclimatic temperatures and model accuracy, and compared coarse-grain temperature maps with microclimatic temperature maps. Understory vegetation structure contributes to microclimatic buffering of near-surface, forest temperatures and enhances the accuracy of maximum temperature predictions during the growing season by altering the effects of solar insolation and topographic convergence index on microclimatic temperatures. Elevation and solar insolation covaried with spatiotemporal mismatches between free-air and microclimatic temperatures, suggesting that these landscape physiographic characteristics may contribute to deviations between macro- and micro-scale temperature. Our findings demonstrate the importance of including complex vegetation characteristics and biophysical interactions as climate forcing factors in microclimate modeling. We also demonstrate the plausibility of accurately predicting microclimatic temperatures over broad extents, an important step in predicting potential organismal responses to climate change.

Higher Diversity in Open Cerrado Supports the Role of Regional Processes in Shaping an Anuran Assemblage in Southeastern Brazil

In this study, we evaluate the role of local and regional factors in shaping the anuran assemblages in the Cerrado biome by contributing to the knowledge on the diversity patterns of different Cerrado vegetation types in southeastern Brazil. We measured richness and abundance of ground dwelling frogs in a gradient of vegetation structural complexity, varying from grassland (campo sujo) to forest (cerradao), using pitfall traps with drift fences and standardized efforts. We also measured vegetation structure by directly counting its components in the field. We found differences in richness and abundance among vegetation types, with richness being higher at more open vegetation types, and abundance being higher at the forest due to the extremely high number of captures of Rhinella ornata, a species from the Atlantic Forest biome. A concordant pattern in anuran diversity and vegetation structure suggests an important role of the habitat in structuring diversity in this group, with open vegetation types sharing both more similar anuran assemblages and vegetation. The higher diversity of Cerrado anurans observed in the open vegetation types in southeastern Brazil is in phase with diversity accounts for other groups of the herpetofauna throughout the biome, and it supports a prevalence of the regional processes over local determinism, a hypothesis that should be formally tested for amphibians with large-scale standardized sampling.

Vegetation, bird and soundscape characterization: a case study in Braulio Carrillo National Park, Costa Rica

We assessed the structural complexity of vegetation, birds and soundscapes in two areas of Braulio Carrillo National Park, Costa Rica, with different road exposure, as baseline information for conservation and management. We measured vegetation structure complexity, surveyed birds and recorded soundscapes in an area adjacent to the National Highway 32 (Quebrada) and another area 20 km away (Ceibo). Quebrada presented a more open forest structure and lower density of trees and shrubs; lower evenness and higher acoustic complexity, higher bioacoustic activity and sound pressure level; higher bird abundance and richness. Ceibo showed a higher density of trees and shrubs, higher complexity of vegetation structure, higher proportion of biophonies than anthrophonies, and an acoustic community with higher diversity and entropy. The study sites differed in characteristics of their bird communities in an unexpected way; these differences appear to be mostly influenced by the structure and complexity of the vegetation surrounding the road. However, the soundscapes seemed to properly reflect the habitat condition, and are promising for evaluating the ecological condition of a site.

Individual tree detection and crown delineation from Unmanned Aircraft System (UAS) LiDAR in structurally complex mixed species eucalypt forests

Estimates of forest stocking density per hectare (NHa) are important in characterising ecological conditions and assessing changes in forest dynamics after disturbances due to pyrogenic, anthropogenic and biotic factors. We use Unmanned Aircraft Systems (UAS) LiDAR with mean point density of 1485 points m−2 across 39 flight sites to develop a bottom-up approach for individual tree and crown delineation (ITCD). The ITCD algorithm was evaluated across mixed species eucalypt forests (MSEF) using 2790 field measured stem locations across a broad range of dominant eucalypt species with randomly leaning trunks and highly irregular intertwined canopy structure. Two top performing ITCD algorithms in benchmarking studies resulted in poor performance when optimised to our plot data (mean Fscore: 0.61 and 0.62), which emphasises the challenge posed for ITCD in the structurally complex conditions of MSEF. To address this, our novel bottom-up ITCD algorithm uses kernel densities to stratify the vegetation profile and differentiate understorey from the rest of the vegetation. For vegetation above understorey, the ITCD algorithm adopted a novel watershed clustering procedure on point density measures within horizontal slices. A Principal Component Analysis (PCA) procedure was then applied to merge the slice-specific clusters into trunks, branches, and canopy clumps, before a voxel connectivity procedure clustered these biomass segments into overstorey trees. The segmentation process only requires two parameters to be calibrated to site-specific conditions across 39 MSEF sites using a Shuffled Complex Evolution (SCE) optimiser. Across the 39 field sites, the ITCD algorithm had mean Fscore of 0.91, True Positive (TP) trees represented 85% of measured trees and predicted plot-level stocking (NP) averaged 94% of actual stocking (NOb). As a representation of plot-level basal area (BA), TP trees represented 87% of BA, omitted trees represented slightly smaller trees and made up 8% of BA, and a further 5% of BA had commission error. Spatial maps of NHa using 0.5 m grid-cells showed that omitted trees were more prevalent in high density forest stands, and that 63% of grid-cells had a perfect estimate of NHa, whereas a further 31% of the grid-cells overestimate or underestimate one tree within the search window. The parsimonious modelling framework allows for the two calibrated site-specific parameters to be predicted (R2: 0.87 and 0.66) using structural characteristics of vegetation clusters within sites. Using predictions of these two site-specific parameters across all sites results in mean FScore of 0.86 and mean TP of 0.77, under circumstances where no ground observations were required for calibration. This approach generalises the algorithm across new UAS LiDAR data without undertaking time-consuming ground measurements within tall eucalypt forests with complex vegetation structure.

Occupancy of avian foraging guilds in soybean fields and borders in Entre R\xedos, Argentina: responses to vegetation structure and prey resources

BackgroundReconciling agriculture and biodiversity conservation is a challenge given the growing demand for agricultural products. In recent decades, Argentina has witnessed agricultural expansion and intensification affecting biodiversity and associated ecosystem services. Within agroecosystems, the level of habitat quality is critical for birds, and may depend on vegetation structure, availability of invertebrate prey, and the use of pesticides. Although the relationship between vegetation structure and avian occurrence has been widely studied, to our knowledge, there are no studies that also incorporate prey availability throughout the cycle of soybean crops in Argentina. We estimated and predicted the effects of land cover and temporal variation on the occurrence of avian foraging guilds in Entre Ríos, Argentina, in order to guide management related to potential ecosystem services provided by birds. We also estimated temporal effects of vegetation structure and insecticides on the main arthropod orders consumed by birds to evaluate prey availability.MethodsWe conducted bird and arthropod surveys for 2 years along transects located in 20 randomly selected soybean fields (N = 60) and their adjacent borders (N = 78) throughout the crop growing season, in four seasons. We estimated avian occupancy, accounting for imperfect detection, and arthropod counts fitting generalized linear mixed models.ResultsThe number of native trees in field borders positively influenced the occurrence of most bird species, mainly insectivores. Granivore foliage gleaners, also were positively affected by grass height. Salliers and aerial foragers were weakly affected by distance to forest and native trees. In general, the availability of invertebrates to birds was highest during the third season. Arthropod counts in borders were greater during the last three crop stages than during the pre-sowing period.ConclusionsWe found that with 10 to 15 native tree species in borders, coupled with a complex vegetation structure with shrubs and grasses, we could conserve a wide spectrum of insectivorous birds, and may contribute to the invertebrate pest control service. Vegetated field borders function as a refuge for arthropods, especially agriculturally beneficial taxa such as Hymenopterans. Finally, several groups of birds use the interior of the fields and could help control pests.

Temporal stability of cavity‐nesting bee and wasp communities in different types of reforestation in southeastern Amazonia

Global initiatives to recover degraded areas have intensified in recent years. However, the effectiveness of different reforestation practices in restoring habitat stability and essential resources for species over time is poorly known. We tested the degree of temporal stability of bee and wasp communities reestablishiment in different types of forest regeneration compared to intact primary forest in southern Amazonia. Using trap‐nest sampling, we collected, during 12 months, information about the nesting species in six different types of treatments: pastures, teak reforestation, fig and mixed native species, natural regeneration forest, and forest primary. We observed that in all reforested treatments, the abundance and richness of both bees and wasps were greater than in pasture sites. However, not all reforestation strategies had the same degree of effectiveness in maintaining the stability of bee and wasp communities over time than observed in primary forest communities. The high temporal variation in teak structure promoted high instability in bee and wasp communities over time. In contrast, reforestation using perennial species, such as fig or mixed species, resulted in a greater temporal stability of bee and wasp communities, although dissimilarity to primary forest remained high. Communities in natural regeneration were the most similar to primary forest, with high similarity of species composition and high temporal stability across seasons. Our findings suggest that reforestation strategies that promote increased complexity of vegetation structure, and better resemble “natural” forests in the provision of habitat resources throughout the year, will better restore and maintain communities through time.

Changes in bat activity over 10 years in silviculturally treated wet sclerophyll forest

A range of silvicultural treatments are applied to timber production forests, resulting in varied vegetation structural complexity. We compared the bat assemblage across three silvicultural treatments (unlogged forest, unthinned regrowth and thinned regrowth), two locations (on and off track) and three time periods (pre-thin, plus one and six years post-thinning) in wet sclerophyll forests, with treatments implemented at a small catchment scale. Linear edges provided important habitat for bats as total bat activity was substantially greater on tracks than off tracks, especially in unlogged and unthinned regrowth forest. Bat activity off track was greater in unlogged areas than in thinned and unthinned regrowth. Activity and species richness off track were greater in thinned than unthinned regrowth, but the time by treatment interaction was not significant for activity, indicating this difference cannot be ascribed to thinning alone. Thinning also led to a species composition that more closely resembled unlogged forest than unthinned regrowth. These patterns in bat activity across silvicultural treatments in wet sclerophyll forests were broadly consistent with other forest types, but subtleties, such as a subdued response to thinning, requires more replication to resolve. Nevertheless, differences between forest types need to be considered when developing management strategies.

Uncertainty in Parameterizing Floodplain Forest Friction for Natural Flood Management, Using Remote Sensing

One potential Natural Flood Management (NFM) option is floodplain reforestation or manage existing riparian forests, with a view to increasing flow resistance and attenuate flood hydrographs. However, the effectiveness of floodplain forests as resistance agents, during different magnitude overbank floods, has yet to be appropriately parameterized for hydraulic models. Remote sensing offers high-resolution datasets capable of characterizing vegetation structure from a variety of platforms, but they contain uncertainty. For the first time, we demonstrate uncertainty propagation in remote sensing derivations of complex vegetation structure through roughness prediction and floodplain flow for extreme flows and different forest types (young and old Poplar plantations, young and old Pine plantations, and an unmanaged riparian forest). The lowest uncertainties resulted from terrestrial and airborne lidar, where airborne lidar is currently best at defining canopy leaf area, but more research is needed to determine wood area. Mean literature uncertainties in stem density, trunk diameter, wood, and leaf area indices (20, 10, 30, 20%, respectively) resulted in a combined Manning’s n uncertainty from 11–13% to 11–17% at 2 m to 8 m flow depths. This equates to 7–8% roughness uncertainty per 10% combined forest structure uncertainty. Individually, stem density and trunk diameter uncertainties resulted in the largest Manning’s n uncertainty at all flow depths, especially for flow though Pine plantations. For deeper flows, leaf and woody areas become much more important, especially for unmanaged riparian forests with low canopy morphology. Forest structure errors propagated to flow depth demonstrate that even small flows can change by a decimeter, while deeper flows can change by 40 cm or more. For flow depth, errors in canopy structure are deemed more severe in flows depths beyond 4–6 m. This study highlights the need for lower uncertainty in all forest structure components using remote sensing, to improve roughness parameterization and flood modeling for NFM.

Impact of agricultural crop type and hunting on bird communities of two villages in Bandung, West Java, Indonesia

Abstract. Hakim L, Abdoellah OS, Parikesit, Withaningsih S. 2020. Impact of agricultural crop type and hunting on bird communities of two villages in Bandung, West Java, Indonesia. Biodiversitas 21: 57-66. Land use change has occurred in the Upper Citarum Watershed over time, converting tropical rain-forest to man-made cash-crop gardens dominate the agricultural landscape, leaving mixed-garden (talun), rice fields and smallholder plantation. This changes species composition, community structure and animal diversity, especially bird species. The objective of this paper was to study bird structure community in rural agricultural landscape in Upper Citarum Watershed. We conducted the survey from February to March 2018. We surveyed birds at 36 point counts (PCs), each PC's surveyed six times for 15 minutes along total 6 km of transects in the agricultural landscape in Sukapura and Resmi Tingal Village, consisting of 12 PCs in mixed-garden, 12 PCs in homegarden and 12 PCs in cash-crop garden. Twenty-nine bird species, 17 families and 1.103 individuals were recorded; 2 species being protected by Indonesian law in all sites, three Javan Island endemics and one species migrant bird species. The insectivorous birds are dominant with 15 species in all land-use types. Passer montanus and Javan munia were the most common birds in all land-use types with 820 of 1.103 individual birds (74,9%) were of two bird species. Mixed-garden had higher bird diversity, species richness, and evenness index than the homegarden and cash-crops garden because of the complexity of vegetation structure and canopy cover stratification. There was a significant decrease in some bird species which in the previous study was dominant to be reduced even to local extinctions such as Oriental White-eye (Zosterops palpebrosus), Crescent-chested Babbler (Stachyris melanothorax) and Western Yellow Wagtail (Motacilla flava). Decreased bamboo-tree garden as Crescent-chested Babbler habitat is suspected to be the cause of declination of this bird population. In addition, unregulated bird hunting is also one of the causes of the declining bird populations, especially birds with market value. Some species such as Oriental White-eye (Zosterops palpebrosus), Sooty-headed Bulbul (Pycnonotus aurigaster), Great Tit (Parus major), Bar-winged prinia (Prinia familiaris), Javan myna (Acridotheres javanicus) and Spotted dove (Streptopelia chinensis) have rapidly decreased population because of bird hunting activities.

The effect of habitat changes along the urbanization gradient for breeding birds: an example from the Xiong'an New Area.

BackgroundBecause of its status as an ecocivilization pilot city, fundamental research on spatial distribution patterns and impact factors of the avian community within the Xiong’an New Area is necessary for future ecological planning and mitigation of negative impacts from future urbanization. Gradient research within small cities can provide important information for the development of urbanization gradient patterns of avian communities.MethodsA total of 30 sample points within the urbanization gradient were selected, and avian communities and environmental variables were measured within a 50 m radius sample circle. Principal component regression analysis was used to analyze bird-environment relationships. The Sorensen dissimilarity index was used to calculate the beta-diversity.ResultsOur results showed that there was a significant urban-rural pattern with a gradient phenomenon in avian communities. Results of this study showed more resident, passenger and insectivore species, and a higher density of breeding insectivore and omnivore individuals appear in the urban fringe than in the other areas. A relatively high value of overall beta-diversity and spatial isolation probably exists among the three disjunct constructed regions. Both species richness and individual abundance were significantly influenced by the species diversity of the trees and foliage height diversity (FHD).DiscussionBased on our results and our goal of avian species diversity conservation, we first suggest that urban green spaces be established and ensure a high complexity of vegetation structure as this is critically needed to increase avian species α-diversity within habitat patches. Second, different habitat types within and around the three constructed areas should be developed based on the important existing bird habitats to increase avian diversity in each city, especially in the areas within Xiongxian and Rongcheng that are well protected, and to elevate the beta-diversity of the total region. Finally, based on the biodiversity hotspots identified by this research, ecological corridors should be carefully planned to improve the stability of regional bird communities.