Increasing Canopy Cover Research Articles

Coyote Predation Effects on White-Tailed Deer Fawns

Coyotes (Canis latrans) are a relatively new predator to the southeastern United States, and may be negatively impacting white-tailed deer (Odocoileus virginianus; hereafter, deer) populations. Our objectives were to evaluate the impacts of coyotes on deer fawns by assessing deer fawn survival and cause-specific mortality, and gain an understanding of factors affecting fawn survival and coyote predation. We captured and radio collared 30 fawns in the Red Hills region of Florida and Georgia, USA (2012-2013). Fawns were monitored for 12 weeks for survival and cause-specific mortality, and we quantified habitat and environmental characteristics of birth sites. Predation (n = 19; 95%) was the leading cause of fawn mortality (n = 20; 67%), with coyote predation (n = 14; 74%) being the most important type of predation. Survival rates for all fawns were greater (P = 0.048) where coyotes were removed compared to non-removal sites, with 50% and 25% of fawns surviving to 12 weeks on coyote-removal and non-removal sites, respectively. Survival rates of fawns ultimately predated by coyotes were greater (P = 0.096) on coyote-removal than non-removal sites, with 40% and 50% of fawns predated by coyotes within 12 weeks on coyote-removal and non-removal sites, respectively. Survival of all fawns and those predated by coyotes was lower when fawns were born at sites with greater hardwood basal area, total basal area, and canopy closure; and survival improved if born in or near hardwood, natural pine, and managed (planted) pine cover types. Increased canopy cover within 10 m of the birth site was selected by adult females for birth sites of all fawns and those that were predated by coyotes. Compared with fawns that lived, all dying fawns and those predated by coyotes had less shrub cover within 5 m and less grass cover at and within 10 m of the birth site. Coyote removal increased fawn daily survival rates, and habitat played a role in fawn survival.

Photosynthetic characteristics of some common temperate freshwater red algal taxa (Rhodophyta)

:We measured photosynthetic–irradiance curves of freshwater red algae in the Batrachospermales and Acrochaetiales from five low-order streams with one to five taxa collected from each stream in the central portion of the Ohio River basin. Four populations of Batrachospermum helminthosum, two populations of B. gelatinosum and Audouinella hermannii and one population of Batrachospermum sp. and Tuomeya americana were sampled. All five species of freshwater red algae were found within a single stream. We observed two distinct groups of algae from this stream: a low photosynthetic efficiency/high initial saturation group and a high photosynthetic efficiency/low initial saturation group distinguished by morphology. Mucilaginous forms, such as B. helminthosum, had significantly greater maximum photosynthesis and efficiency compared to those of the more “tuftlike” or compact morphology, such as A. hermannii. Photosynthetic responses of B. helminthosum in four streams showed a positive relationship with maximum photosynthesis and efficiency with increasing canopy cover. Comparing B. gelatinosum and A. hermannii from two sites, we observed no significant impact of canopy cover. Ratios of photosynthesis to respiration were greater than one for all of the taxa studied, suggesting that freshwater red algae can be an important source of in-stream production. Our findings support previous work suggesting that both algal morphology as well as light environment alter photosynthetic responses of freshwater red algae. Understanding how species respond to varied light availabilities will increase our understanding of the ecological role, biogeography, habitat preferences and within-watershed distribution of these important benthic primary producers in streams.

Comparing ALS and Image-Based Point Cloud Metrics and Modelled Forest Inventory Attributes in a Complex Coastal Forest Environment

Digital aerial photogrammetry (DAP) is emerging as an alternate data source to airborne laser scanning (ALS) data for three-dimensional characterization of forest structure. In this study we compare point cloud metrics and plot-level model estimates derived from ALS data and an image-based point cloud generated using semi-global matching (SGM) for a complex, coastal forest in western Canada. Plot-level estimates of Lorey’s mean height (H), basal area (G), and gross volume (V) were modelled using an area-based approach. Metrics and model outcomes were evaluated across a series of strata defined by slope and canopy cover, as well as by image acquisition date. We found statistically significant differences between ALS and SGM metrics for all strata for five of the eight metrics we used for model development. We also found that the similarity between metrics from the two data sources generally increased with increasing canopy cover, particularly for upper canopy metrics, whereas trends across slope classes were less consistent. Model outcomes from ALS and SGM were comparable. We found the greatest difference in model outcomes was for H (ΔRMSE% = 5.04%). By comparison, ΔRMSE% was 2.33% for G and 3.63% for V. We did not discern any corresponding trends in model outcomes across slope and canopy cover strata, or associated with different image acquisition dates.

Regeneration response of Brazilian Atlantic Forest woody species to four years of Megathyrsus maximus removal

Guinea-grass (Megathyrsus maximus (Jacq.) B.K. Simon & S.W.L. Jacobs – Poaceae) is an invasive C4 grass that known to slow ecological succession in restoration sites. This study aimed to evaluate the responses of the woody species and M. maximus itself to manual removal in a 20-year-old reforestation site. Forty-five 5×5-m plots were established in 2008 and evaluated until 2012. The plots were divided into three treatments: control (CON), manual removal for one year (MR1), and manual removal for two years (MR2). All individuals of woody species >10cm were sampled. Canopy cover, grass cover, and the number of seedlings of M. maximus were also recorded. After the first weeding, M. maximus seedlings were manually uprooted every four months, for a total of three times in MR1 (2008–2009) and six times in MR2 (2008–2010). After the manual removal was stopped, the seedlings of M. maximus were counted and were allowed to grow in order to assess its reestablishment potential. The number of new grass seedlings decreased drastically after the first year with repeated removals and did not differ between removal treatments at any time, even after removals halted, indicating that one year of removal was sufficient to displace the grass. With the exclusion of Guinea-grass, an increase in the abundance and richness of other exotic species was observed until the second year. However, the increase in canopy cover during the four years likely benefited native woody species and impaired M. maximus and other exotics. In addition, after four years, although the woody species richness did not differ between the three treatments, the total abundance and pioneer species richness were higher in both removal treatments. These findings suggest that the grass slows ecological succession. However, both the increase in canopy cover and decrease in grass cover indicate that, in the absence of fire, native vegetation will suppress Guinea-grass. Furthermore, grass removal from the understory of early secondary forests and reforestations can be used to accelerate succession, reducing both fire risk and failures of ecological restoration initiatives.

AVALIAÇÃO DO DESENVOLVIMENTO VEGETATIVO DE PEREIRAS ‘HOSUI’ E ‘ROCHA’ EM DIFERENTES ESPAÇAMENTOS NO SISTEMA DE CULTIVO ORGÂNICO

RESUMO O objetivo deste trabalho foi verificar a influência de diferentes espaçamentos de plantio sobre o crescimento vegetativo de pereiras das cvs. Rocha e Hosui, em sistema orgânico de produção. As mudas das pereiras ‘Rocha’ e ‘Hosui’ enxertadas sobre o marmeleiro ‘CP’ foram plantadas em setembro de 2009. Os espaçamentos utilizados foram: 1,0; 0,8; 0,6 e 0,4 m, entre plantas por 3,5 m entre linhas, equivalendo às densidades de plantio de 2.857; 3.571; 4.762 e 7.143 plantas ha-1, respectivamente. Por dois ciclos consecutivos - 2011/2012 e 2012/2013 -, referentes ao terceiro e ao quarto anos após o plantio, respectivamente, foram avaliadas as variáveis diâmetro detronco, diâmetro de ramos e número de ramos. No segundo ciclo, foram avaliados o volume de copa, a área foliar estimada, a cobertura do dossel e os teores de clorofila a, b e total. Considerando as variáveis: projeção vertical de área foliar estimada, volume de copa e diâmetro de tronco e ramos, para a cv. Hosui, observou-se maior vigor vegetativo em relação à cv. Rocha. A cv. Rocha apresentou redução dos teores de clorofila no menor espaçamento entre plantas, enquanto na cv. Hosui os teores de clorofila não variaram com o espaçamento. Ocorreu aumento da área foliar estimada em função do adensamento para as duas cultivares; para o volume de copa, porém, este efeito foi observado apenas para a cv. Hosui, e para o índice de cobertura de dossel, apenas para a cv. Rocha. O maior adensamento de plantio favoreceu as pereiras da cv. Hosui, proporcionando maior volume de copa por área de terreno, sem ocorrer redução dos teores foliares de clorofila, mas com aumento da cobertura do dossel. Para a cv. Rocha, no entanto, adensamentos maiores do que 4.700 plantas ha-1 parecem ser prejudiciais, visto promoverem redução dos teores foliares de clorofila, porém com maior cobertura do dossel, podendo indicar autossombreamento.

Simulated impacts of climate change on water use and yield of irrigated sugarcane in South Africa

Reliable predictions of climate change impacts on water use, irrigation requirements and yields of irrigated sugarcane in South Africa (a water-scarce country) are necessary to plan adaptation strategies. Although previous work has been done in this regard, methodologies and results vary considerably. The objectives were (1) to estimate likely impacts of climate change on sugarcane yields, water use and irrigation demand at three irrigated sugarcane production sites in South Africa (Malelane, Pongola and La Mercy) for current (1980–2010) and future (2070–2100) climate scenarios, using an approach based on the Agricultural Model Intercomparison and Improvement Project (AgMIP) protocols; and (2) to assess the suitability of this methodology for investigating climate change impacts on sugarcane production.Future climate datasets were generated using the Delta downscaling method and three Global Circulation Models (GCMs) assuming atmospheric CO2 concentration [CO2] of 734ppm (A2 emissions scenario). Yield and water use were simulated using the DSSAT-Canegro v4.5 model.Irrigated cane yields are expected to increase at all three sites (between 11 and 14%), primarily due to increased interception of radiation as a result of accelerated canopy development. Evapotranspiration and irrigation requirements increased by 11% due to increased canopy cover and evaporative demand. Sucrose yields are expected to decline because of increased consumption of photo-assimilate for structural growth and maintenance respiration. Crop responses in canopy development and yield formation differed markedly between the crop cycles investigated.Possible agronomic implications of these results include reduced weed control costs due to shortened periods of partial canopy, a need for improved efficiency of irrigation to counter increased demands, and adjustments to ripening and harvest practices to counter decreased cane quality and optimise productivity.Although the Delta climate data downscaling method is considered robust, accurate and easily-understood, it does not change the future number of rain-days per month. The impacts of this and other climate data simplifications ought to be explored in future work. Shortcomings of the DSSAT-Canegro model include the simulated responses of phenological development, photosynthesis and respiration processes to high temperatures, and the disconnect between simulated biomass accumulation and expansive growth. Proposed methodology refinements should improve the reliability of predicted climate change impacts on sugarcane yield.

Ground-foraging ant communities vary with oil palm age

The conversion of natural habitats to croplands is a major cause of the global loss of species diversity and ecosystem services. One potentially effective method for enhancing the biodiversity of important groups such as insects, and their associated ecosystem services within croplands, is to increase the environmental complexity of the agricultural matrix. This can be achieved in perennial tree crops by planting mixed-age stands. There is, however, very little evidence for the effects of stand age on biodiversity in tropical tree crops. In this study, we assess how ground-foraging ant communities differ in relation to oil palm stand age, currently the dominant tree crop across tropical Southeast Asia. Oil palm age did not affect overall ant species richness. However, the numbers of species that were either common or numerically-dominant decreased with increases in canopy cover, which positively correlated with oil palm age, suggesting greater species evenness in older oil palm. In mature, but not young, oil palm, ant species co-occurred non-randomly, suggesting competitive exclusion and species segregation. Species responses to variables associated with oil palm age depended on their functional group. Generally, opportunists and generalized myrmicines were less abundant and less diverse, whereas specialist predators were more abundant and diverse, in older oil palm. Our results show that ground-foraging ant communities in oil palm change significantly in composition, but not in species richness, with crop age. These results suggest that mixed-age stands could support compositionally variable communities and help boost insect diversity in otherwise homogeneous perennial monocultures.

Influence of habitat structure on Pristimantis species (Anura: Craugastoridae) in a bamboo-dominated forest fragment in southwestern Amazonia

Structural and determinate factors for the composition of assemblages of species are diverse. Two theories attempt to explain the pattern of species composition in assemblies using different approaches—i.e., Niche Theory and Neutral Theory. Anurans have complex responses to habitat structure. Species of Pristimantis are good indicators for conservation because they are organisms with direct development. The effect of habitat structure on species of Pristimantis in a bamboo-dominated remnant forest located in southwestern Amazonia is analyzed herein. Active visual and auditory searches in 10 plots of the Biodiversity Research Program (PPBio) were conducted between November 2012 and May 2013. Four hundred and sixty individuals of five species were recorded: Pristimantis altamazonicus, P. diadematus, P. fenestratus, P. reichlei, and P. skydmainus. Neither spatial distance nor the structure of the habitat of the plots affected the composition of Pristimantis. The first axis of PCA explained 45.6% variation of the characterization habitat structure, correlated significantly with the number of Pristimantis, species increasing with trees between 10 ≤ dbh < 30 cm and decreased with density of bamboo. The increase in litter depth and canopy cover influenced in the occurrence of P. reichlei, the occurrence of P. skydmainus decreased with increased density of bamboo and trees dbh ≥ 30 cm and the occurrence of P. diadematus decreased relative to increased canopy cover. Pristimantis diadematus and P. skydmainus were the most restricted species in terms of habitat and were especially susceptible to bamboo density.

The Twinflower (Linnaea borealis L.) in the northern part of the Południowopodlaska Lowland

Abstract Linnaea borealis, the twinflower, is considered a critically endangered species in the Południowopodlaska Lowland. The disappearance of the twinflower is mainly caused by habitat changes resulting from forest management, but also light deficiency due to the increase in canopy cover and growth of the shrub layer (processes of succession). The aim of the paper is to present the actual distribution and phytosociological characteristics of L. borealis in the northern part of the Południowopodlaska Lowland. In this region, only three out of ten known areas of occurrence (Werchliś, Serpelice, Grala-Dąbrowizna) have endured to the present day. The twinflower occurs in pine forest, Peucedano-Pinetum, and mixed forest, Querco roboris-Pinetum, communities. A decrease in the ground cover of twinflower populations was observed in all existing twinflower locations. Although the area covered by the Linnaea borealis population in Werchliś increased tenfold during the last 20 years (from about 200 m2 in 1993 to 1970 m2 in 2013), its cover-abundance according to the Braun-Blanquet scale decreased from 5 to 3. The increase in the area covered by the twinflower population together with the accompanying decrease in cover-abundance is probably not a manifestation of species dynamics but rather a response to disadvantageous environmental changes (growth of canopy cover and shrub layer). Progressive light reduction can initiate the process of fragmentation of a population. A decrease in the cover-abundance of the L. borealis population (from 4 to 2) was also observed in Serpelice. Its area was reduced to half of its original size due to anthropogenic destruction of this location. In the third region, Grala-Dąbrowizna, also the negative effects of competitive species (e.g. Vaccinium myrtillus, V. vitis-idaea) are considered.

Spatial variation in periphyton fatty acid composition in subtropical streams

SummaryBenthic algae play an important role in many stream food webs, not only serving as a major carbon source but also influencing energy transfer as the primary source of polyunsaturated fatty acids (PUFA). Dietary deficiency inPUFAcan limit animal growth and reproduction. AlgalPUFAcontent can vary considerably in response to abiotic factors.We conducted a field investigation in streams in South‐East Queensland, Australia, to identify environmental factors affecting the fatty acid composition of periphyton.Riparian canopy cover andNOx‐Nconcentrations explained most of the observed variation in periphyton fatty acid profiles.NOx‐Nconcentrations showed negative relationships with most saturated fatty acids (SAFA), while mono‐unsaturated fatty acids (MUFA) and the fatty acids 16:0 and 16:1ω7 were negatively correlated with canopy cover. In contrast, the percentage of highly unsaturated fatty acids (HUFA) in periphyton was greater with increasing canopy cover regardless ofNOx‐Nconcentrations.Variation in riparian canopy cover and nutrients gave rise to opposite outcomes in terms of periphyton food quality and quantity. The highest periphyton food quality, measured byHUFAcontent, occurred in streams with high canopy cover and low nutrients, while the highest periphyton food quantity occurred in streams with low canopy cover.Our study suggests that changes in riparian vegetation and/or nutrient inputs can significantly alter the fatty acid content of periphyton, with important implications for aquatic consumers. We recommend that future studies on impacts of riparian clearing or nutrient enrichment in stream ecosystems place more attention on the effects of food quality rather than quantity.

Forest canopy structural controls over throughfall affect soil microbial community structure in an epiphyte‐laden maritime oak stand

AbstractIdentifying spatiotemporal influences on soil microbial community (SMC) structure is critical to our understanding of patterns in biogeochemical cycling and related ecological services (e.g. plant community structure, water quality, and response to environmental change). Because forest canopy structure alters the spatiotemporal patterning of precipitation water and solute supplies to soils (via ‘throughfall’), is it possible that changes in SMC structure could arise from modifications in canopy elements? Our study investigates this question by monitoring throughfall water and dissolved ion supply to soils beneath a continuum of canopy structure: from large gaps (0% cover), to bare Quercus virginiana Mill. (southern live oak) canopy (~50–70%), to heavy Tillandsia usneoides L. (Spanish moss) canopy (>90% cover). Throughfall water supply diminished with increasing canopy cover, yet increased wash off/leaching of Na+, Cl‐, PO43‐, and SO42‐ from the canopy to the soils. Presence of T. usneoides diminished throughfall NO3‐, but enhanced NH4+, concentrations supplied to subcanopy soils. The mineral soil horizon (0–10 cm) sampled in triplicate from locations receiving throughfall water and solutes from canopy gaps, bare canopy, and T. usneoides‐laden canopy significantly differed in soil chemistry parameters (pH, Ca2+, Mg2+, and cation‐exchange capacity). Polymerase chain reaction denaturant gradient gel electrophoresis banding patterns beneath similar canopy covers (experiencing similar throughfall dynamics) also produced high similarities per analyses of similarity and clustered together when analysed by nonmetric multidimensional scaling. These results suggest that modifications of forest canopy structures are capable of affecting mineral soil horizon SMC structure via throughfall when canopies' biomass distribution is highly heterogeneous. As SMC structure, in many instances, relates to functional diversity, we suggest that future research seek to identify functional diversity shifts (e.g. nitrogen transformation) in response to canopy structural alterations of throughfall water/solute concentration. Copyright © 2015 John Wiley & Sons, Ltd.

Managing tropical agroforestry for conservation of flocking migratory birds

Agroforestry systems have great potential to conserve biodiversity in highly-altered tropical landscapes. Although certain types of agroforestry, such as shade-coffee and cacao, are well known to support a diverse assemblage of resident and migratory birds, the ability of silvopastures to contribute to bird conservation is poorly understood. Important physiognomic differences among agroforestry systems suggest that the most effective habitat management strategies to support migratory birds may likewise differ. We surveyed two common agroforestry systems, shade-coffee plantations and silvopastures, in the Colombian Andes from 2011 to 2013 to identify which physiognomic features were most heavily associated with use by mixed-species flocks and migratory birds. Contrary to our expectations, the same management strategies may perform well in both systems. Flock activity increased with increasing canopy cover and tree density in both shade-coffee and silvopastoral systems. In addition, abundances of several migratory bird species within flocks increased with tree basal area and structural complexity, indicating that complex agroforests with a mid-range of canopy cover will provide the most suitable habitat for migrants attending mixed-species flocks. Our study suggests that suitability of shade-coffee and silvopastoral systems can be improved for overwintering migrants by increasing canopy cover to 25–40 % and incorporating emergent shade trees to produce a basal area of >5 m2/ha.

Sample Grain Influences the Functional Relationship Between Canopy Cover and Gopher Tortoise (Gopherus polyphemus) Burrow Abandonment

Abstract Change in vegetation structure alters habitat suitability for the threatened gopher tortoise (Gopherus polyphemus). An understanding of this dynamic is crucial to inform habitat and tortoise management strategies. However, it is not known how the choice of the sample grain (i.e., cell size) at which vegetation structure is measured impacts estimates of tortoise–habitat relationships. We used lidar remote sensing to estimate canopy cover around 1573 gopher tortoise burrows at incrementally larger sample grains (1–707 m2) in 450 ha of longleaf pine (Pinus palustris) savanna. Using an information theoretic approach, we demonstrate that the choice of grain size profoundly influences modeled relationships between canopy cover and burrow abandonment. At the most supported grain size (314 m2), the probability of burrow abandonment increased by 1.7% with each percent increase in canopy cover. Ultimately, detecting the appropriate sample grain can lead to more effective development of functional relations...

Vegetation structure and composition determine snowshoe hare (Lepus americanus) activity at arctic tree line

Snowshoe hares (Lepus americanus Erxleben, 1777) are keystone herbivores supporting many boreal-forest predators. Understanding habitat use of hares can help predict how hares and their predators will be affected by disturbances such as climate change, which will have a particularly strong effect at tree line. We examined hare activity at arctic tree line near Churchill, Manitoba, using fecal pellet transects established in August 2012. We counted all hare fecal pellets at two plots per transect and measured plant abundance and vegetation structure surrounding the plots, then used model selection to determine the combinations of habitat features or plant species that best explained hare activity or presence. Hare pellets occurred at a higher density where tall shrub cover was high. Pellet density also increased with increasing canopy cover, tree size, tree density, visibility, and small shrub cover, but was negatively correlated with medium-sized shrub and herb cover. Hares preferred areas with willow (genus Salix L.) and avoided areas with unpalatable black spruce (Picea mariana (Mill.) Britton, Sterns & Poggenb.). With climate warming, tree line is expected to advance northward and the increased tall shrub and willow cover predicted with increasing temperatures should benefit hares by providing greater predator protection and food.

Warming-Induced Shrub Expansion and Lichen Decline in the Western Canadian Arctic

Strong evidence for a pan-Arctic expansion of upright shrubs comes from analysis of satellite imagery, historical photographs, vegetation plots, and growth rings. However, there are still uncertainties related to local-scale patterns of shrub growth, resulting interactions among vegetation functional groups, and the relative roles of disturbance and climate as drivers of observed change. Here, we present evidence that widespread and rapid shrub expansion and lichen declines over a 15,000 km2 area of the western Canadian Arctic have been driven by regional increases in temperature. Using 30 m resolution Landsat satellite imagery and high resolution repeat color-infrared aerial photographs, we show that 85% of the land surface has a positive 1985–2011 trend (P 0.03 NDVI/decade) occurred consistently across all landscape positions and most vegetation types. Comparison of 208, 1:2,000 scale vertical air photo pairs from 1980 and 2013 clearly shows that this greening was driven by increased canopy cover of erect dwarf and tall shrubs, with declines in terricolous lichen cover. Disturbances caused by wildfires, exploratory gas wells, and drained lakes all produced strong, yet localized increases in NDVI due to shrub growth. Our analysis also shows that a 4°C winter temperature increase over the past 30 years, leading to warmer soils and enhanced nutrient mineralization provides the best explanation for observed vegetation change. These observations thus provide early corroboration for modeling studies predicting large-scale vegetation shifts in low-Arctic ecosystems from climate change.

Treeline advances along the Urals mountain range - driven by improved winter conditions?

High-altitude treelines are temperature-limited vegetation boundaries, but little quantitative evidence exists about the impact of climate change on treelines in untouched areas of Russia. Here, we estimated how forest-tundra ecotones have changed during the last century along the Ural mountains. In the South, North, Sub-Polar, and Polar Urals, we compared 450 historical and recent photographs and determined the ages of 11,100 trees along 16 altitudinal gradients. In these four regions, boundaries of open and closed forests (crown covers above 20% and 40%) expanded upwards by 4 to 8 m in altitude per decade. Results strongly suggest that snow was an important driver for these forest advances: (i) Winter precipitation has increased substantially throughout the Urals (~7 mm decade(-1) ), which corresponds to almost a doubling in the Polar Urals, while summer temperatures have only changed slightly (~0.05°C decade(-1) ). (ii) There was a positive correlation between canopy cover, snow height and soil temperatures, suggesting that an increasing canopy cover promotes snow accumulation and, hence, a more favorable microclimate. (iii) Tree age analysis showed that forest expansion mainly began around the year 1900 on concave wind-sheltered slopes with thick snow covers, while it started in the 1950s and 1970s on slopes with shallower snow covers. (iv) During the 20th century, dominant growth forms of trees have changed from multistemmed trees, resulting from harsh winter conditions, to single-stemmed trees. While 87%, 31%, and 93% of stems appearing before 1950 were from multistemmed trees in the South, North and Polar Urals, more than 95% of the younger trees had a single stem. Currently, there is a high density of seedlings and saplings in the forest-tundra ecotone, indicating that forest expansion is ongoing and that alpine tundra vegetation will disappear from most mountains of the South and North Urals where treeline is already close to the highest peaks.

Projecting canopy cover change in Tasmanian eucalypt forests using dynamically downscaled regional climate models

Loss of forest cover is a likely consequence of climate change in many parts of the world. To test the vulnerability of eucalypt forests in Australia’s island state of Tasmania, we modelled tree canopy cover in the period 2070–2099 under a high-emission scenario using the current climate–canopy cover relationship in conjunction with output from a dynamically downscaled regional climate model. The current climate–canopy cover relationship was quantified using Random Forest modelling, and the future climate projections were provided by three dynamically downscaled general circulation model (GCM) simulations. Three GCMs were used to show a range of projections for the selected scenario. We also explored the sensitivity of key endemic and non-endemic Tasmanian eucalypts to climate change. All GCMs suggested that canopy cover should remain stable (proportional cover change <10 %) across ~70 % of the Tasmanian eucalypt forests. However, there were geographic areas where all models projected a decline in canopy cover due to increased summer temperatures and lower precipitation, and in addition, all models projected an increase in canopy cover in the coldest part of the state. The model projections differed substantially for other areas. Tasmanian endemic species appear vulnerable to climate change, but species that also occur on the mainland are likely to be less affected. Given these changes, restoration and carbon sequestration plantings must consider the species and provenances most suitable for future, rather than present, climates.

Vegetative Characteristics of Bachman's Sparrow Habitat in the West Gulf Coastal Plain

Abstract While Peucaea aestivalis (Bachman's Sparrow) will use several habitat types (e.g., pine savanna, pine plantations, clear cuts, abandoned fields), specific vegetative conditions must be present for a site to be acceptable. Bachman's Sparrow presence/absence was examined in forested (mature Pinus palustris [Longleaf Pine] forest and mid-aged pine plantations) and early successional habitats (clear cuts and three-year-old pine plantations) to determine which vegetation variables were best for predicting sparrow occurrence. Across all sampled habitats, the probability of Bachman's Sparrow presence increased with increases in canopy cover and percent grass groundcover. Probability of presence decreased with increases in shrub-layer rating and percent bare ground. When considering only forested habitats, the probability of Bachman's Sparrow presence increased with increasing canopy cover and percent grass groundcover, but decreased with increasing canopy height, shrub height, and stand basal area. In e...

Puittaimestiku kaardistamine aerolidari andmete põhjal metsana lisanduvatel aladel/ Estimation of fractional forest cover from airborne laser scanning data in abandoned agricultural land

Abstract The abandonment of agricultural land is an actual problem in Estonia due to significant impact on landscape ecology and structure. Abandoned agricultural fields are usually converting into forest. Mapping of agricultural land use is a strategic interest of each country. Airborne laser scanning (ALS) is used in many countries for topographical mapping and the laser pulse return positions are promising datasets for mapping the abandonment of agricultural land. We used ALS data based woody plant canopy cover estimates made at certain reference height unachievable for field crops to map abandoned agricultural land in nine test sites in Tartumaa, Estonia. The maximum height of trees in test sites ranged from 6.5 m to 13.4 m. The lidar pulse returns based canopy cover estimate was assessed 1) by using ortophoto based digitized maps of tree canopy, 2) repeated measurements made with plant canopy analyzer LAI-2000 and 3) by using allometric crown radius models and repeated tree measurements from sample plots. The interpretation of canopy boundaries and separation of small spaces between tree crowns from ortophotos is a challenging task for an operator. The relationship between ALS based canopy cover and ortophoto based canopy cover was linear in all test sites except when ALS data from beginning of June were used. It the beginning of June foliage is not fully developed on trees. An increase in the woody canopy cover was detected from repeated LAI-2000 measurements and also from repeated tree measurements-based simulated crowns. The impact of reference height change from 2.0 m to 1.3 m on canopy cover estimations was not significant and much smaller compared to the tree growth induced increase in canopy cover, indicating that similar errors originating from e.g. digital elevation model are not problematic for the proposed method in practical applications.

The response of ground-dwelling spiders (Araneae) and hoverflies (Diptera: Syrphidae) to afforestation assessed using within-site tracking

In manycountries throughout the world, the area of plantation forests continues to increase and they now dominate many landscapes. In recent decades, forest cover in Ireland has expanded largelydue to commercial afforestation with non-native conifers. This study provides the first within-site assessment of the response of two important arthropod groups to afforestation in agricultural grasslands in Ireland. Five sites were studied 1 year beforeand7yearsafterafforestationusingpitfalltrappingforactiveground-dwellingspidersandMalaisetrapping forhoverflies.Bothspeciesgroupswerestudiedingrasslandhabitat,andspiderswerealsosampledinfieldboundaryhedgerowhabitat.Afforestationwithinthestudysiteshadapositiveeffectonground-dwellingspiderdiversity over the first 7 years; total species richness increased in afforested grassland and hedgerow habitats, and forest specialist species richness increased in afforested grassland habitat. This was concurrent with, and most likely influenced by, the increase in habitat structure created by the forest vegetation, litter and deadwood layers and the increase in canopy cover. There was no effect of afforestation on hoverfly species richness over the first 7 years, possibly due to confounding effects of hoverfly movements across landscapes. Spider and hoverfly species compositions were also positively affected by afforestation. These results indicated that afforestation in our study sites, set within a predominantly agricultural landscape, benefitted arthropod diversity by increasing habitat diversity. Hedgerow habitats were also an important contributor to biodiversity in these newly planted forests. Ecologically oriented planning and management of afforestation must consider the influence of habitat quality in forest plantations, including the protection of biodiversity rich habitats and the quality of the land being afforested, to improve the contribution to biodiversity enhancement and conservation.