Forest Plant Communities Research Articles

New records of Gerrhonotus parvus Knight & Scudday, 1985 (Squamata, Anguidae) in the state of Coahuila, México

We document the first records of Gerrhonotus parvus in the state of Coahuila, México. From March 2012 to March 2017, 6 males and 2 females were found in pine forest and submontane scrubland plant communities in the Sierra de Zapalinamé Natural Protected Area, which is located in the municipalities of Saltillo and Arteaga. These records extend the known distribution of the species 28–44 km west of the nearest occurrences in the state of Nuevo León.

Forest sites and forest types on rendzinas in Poland

Abstract The article discusses the relationship between rendzinas and types of forest sites and plant communities in lowland, upland and mountain areas in Poland. Rendzinas as soils of forest sites play an important role in the uplands of southern Poland. In mountain areas, their preponderance is limited to the area of the Pieniny and the Western Tatras. The site-forming role of rendzinas in the upland areas depends mainly on geomorphological conditions. Typical rendzinas generally form eutrophic sites of multi-species oak-hornbeam forests, fertile beech forests and thermophilous beech forests. Rendzinas with lithological discontinuities usually create poorer form sites of mixed deciduous forests, which correspond to floristically poorer phytocenoses of acidophilous deciduous forests. In mountain areas, the climate and geomorphological processes form the zonation of vegetation and rendzinas. In vertical layout sites, the rendzinas change from fertile sites of fir and beech forests, through mesotrophic mixed forests sites, to spruce forest on limestone in the upper montane zone.

Projected regional forest plant community dynamics evidence centuries‐long effects of habitat turnover

AbstractQuestionsMany Western European and North American countries have been experiencing strong reforestation in the last two centuries due to agricultural abandonment. Other land‐use changes, such as urbanization, can simultaneously trigger forest erosion. In this context of habitat turnover, forest understorey plant dynamics depend on the balance between immigration credit in post‐agricultural forest and extinction debt in ancient forest. The transient and final community properties following concomitant habitat creation and destruction are poorly known. In this contribution, we study the projected transient regional forest plant dynamics and identify the determinants of the relaxation duration at both landscape and patch scales.LocationSeine‐et‐Marne region, France.MethodsSpecies’ incidences are projected in 9,208 patches of the Seine‐et‐Marne region characterized by strong development of post‐agricultural forests and a moderate erosion of ancient forests during the period 1840–2000. We use a metapopulation model with static biodiversity data and landscape history to project forest plant dynamics. We focus on 33 generalist forest species that are able to colonize both ancient and post‐agricultural forests.ResultsOur analyses reveal that (1) extinction in ancient forests slows the colonization process, which lasts between 250 and 990 years after habitat turnover, depending on species characteristics; (2) the species incidence in post‐agricultural forests converges towards that in ancient forests long before the overall species incidence stabilizes at the landscape scale (i.e. long before the relaxation time); (3) landscape‐ and patch‐scale relaxation times depend on species colonization ability and patch functional connectivity; (4) the colonization process is rather slow for ancient forest species; and (5) the incidence of ancient forest species becomes larger than the incidence of other species at the end of the colonization dynamics thanks to their strong persistence.ConclusionsAncient forest species may potentially benefit from a large immigration credit but need centuries to use it. On such time scales, many perturbations are likely to jeopardize the realization of this potential credit.

Factors determining floristic composition and functional diversity of plant communities of Mount Oku forests, Cameroon

Mount Oku, in north-western Cameroon, holds many endemic and restricted-range species. This study identifies factors influencing the species and functional diversity of plant communities in Mount Oku forests. We specifically look at whether the altitudinal gradient, which classically structures the mountain vegetation, has shifted in response to the influence of human activities. To explore variations in the vegetation composition of the study area, we realized 102 floristic plots along an altitudinal gradient and environmental conditions records (abiotic and biotic variables, human proximity indexes, and land uses at certain periods). Plant species identified were also characterized by a series of life traits (biological type, type of diaspore, leaf size, phytogeography, dispersal pattern, and altitudinal distribution). Multivariate analyses (nonmetric multidimensional scaling and coinertia) have identified the main types of forest vegetation and link functional diversity to environmental factors. The results show that humans have altered the functional composition of vegetation by rearing domestic animals in the understorey forest near the summit. The results also show that it is sometimes difficult to separate the effect of the altitude from the effect of human presence on the plant composition. Greater efforts of biodiversity conservation in high species-rich areas in Mount Oku should be made.

Restore it, and they will come: trap-nesting bee and wasp communities (Hymenoptera: Aculeata) are recovered by restoration of riparian forests

Riparian forests have been greatly affected by anthropogenic actions with formerly continuous riparian forests being slowly converted into small and isolated patches. Riparian forests are extremely important habitats for many groups of insects, including bees and wasps, because they are sources of shelter and food for them and their offspring. There is a growing body of evidence of success in the restoration of riparian forest plant communities; however, little research has been done on the associated invertebrate communities. We test whether restoring plant communities is sufficient for restoring the taxonomic composition of trap-nesting bees and wasps and which functional traits are favored in different sites. We predict that species richness, abundance, and community composition of trap-nesting bees and wasps of riparian sites undergoing restoration will converge on the “target” of a reference site with increasing time, since restoration increases habitat complexity. We also predict that the width of restored patches will also influence the species richness, abundance and community composition of trap-nesting bees and wasps. Bee richness and abundance, and wasp richness, were strongly related to fragment width, but not to age since restoration. Our results indicate that although restored sites are relatively small and scattered in a fragmented landscape, they provide suitable habitat for re-colonization by community assemblages of trap-nesting bees and wasps and the traits selected captured the responses to the habitat restoration. Hence, restored riparian areas can be considered important habitats for invertebrates, thus contributing to an increase in local biodiversity and, possibly, the restoration of some of the ecosystem services they originally provided.

Effects of connectivity on animal‐dispersed forest plant communities in agriculture‐dominated landscapes

AbstractQuestionsHow does connectivity affect animal‐dispersed plant assemblages in woodlots of agriculture‐dominated landscapes? Is this effect dependent on zoochorous dispersal modes?LocationLong‐Term Socio‐Ecological Research (LTSER) site of “Zone Atelier Armorique” (ca. 150 km2), Brittany, western France.MethodsWe sampled 26 small post‐agricultural woodlots embedded in an agricultural matrix (1–7 ha). We assessed the connectivity of each woodlot using habitat reachability metrics (i.e. Proportion of Total Potential Dispersal Flux in the Landscape) calculated along a range of dispersal distances from 100 to 1,500 m. This metric was based on graph theory and was calculated as a function of landscape matrix permeability to animal movement (i.e. seed plant dispersal vectors). We analysed the composition of plant assemblages in the core and margins of woodlots. We calculated the proportion of species richness and cover of zoochorous species within these assemblages and for specific zoochorous modes (i.e. epi‐, endo‐ and dys‐zoochorous species). We analysed the effects of Proportion of Total Potential Dispersal Flux at different dispersal distances and woodlot sizes on the functional dispersal structure of the plant community using linear models.ResultsWe demonstrated that overall plant zoochorous assemblages only depend on woodlot size in the range of dispersal distances tested. The proportion of richness of zoochorous species within the community increased with habitat size. Connectivity influenced only the relative proportions of the different zoochorous modes, except for the dys‐zoochorous group, which was primarily influenced by woodlot size. Both epi‐zoochorous and endo‐zoochorous species were impacted by the interaction between connectivity and woodlot area. Connectivity increased the proportion of epi‐zoochorous species richness and the proportion of endo‐zoochorous cover in assemblages in large woodlots. These effects were detected at short dispersal distances. Our results were supported in both total and core plant assemblages.ConclusionThis study indicates that both habitat isolation and decrease in habitat size contribute towards shaping the functional structure of the plant community, but they act at different levels of dispersal mode. Our results suggest that in these fragmented landscapes long‐distance dispersal has been lost either because of the selection of small‐sized animal movements or of the rareness of plant species needing large habitat size. Maintaining woodlot connectivity in the woodland surroundings seems to be sufficient to preserve short‐distance dispersal, although a more thorough restoration of landscape connectivity is necessary to recover the functional composition of the community with the whole set of dispersal patterns.

Plant, herbivore and parasitoid community composition in native Nothofagaceae forests vs. exotic pine plantations

Abstract Converting natural areas into land used for production causes dramatic changes in the configuration of landscapes. Both the loss and fragmentation of native habitats contribute to biodiversity loss world‐wide and the consequent creation of artificial edges can have a significant influence on community assembly. The conservation value of plantation forests has been identified for specific species, but it is not clear whether exotic pine plantations can also be used for the preservation of native communities in general. We studied whether community composition of different trophic levels (plants, herbivorous caterpillars, parasitoids) changed across native Nothofagaceae forests to exotic pine plantations, and whether habitat edges affected communities differently depending on the forest type considered. To accomplish this, we sampled plants, herbivorous caterpillars and parasitoids in native Nothofagaceae and exotic pine plantation forests and compared community composition of each trophic level across habitats. We found that community composition of plants, herbivorous caterpillars and parasitoids differed significantly between native and exotic plantation forests, and that variation in the composition of the upper trophic levels was strongly dependent on variation in the composition of the lower trophic level. Moreover, differences in community composition were mostly the result of species turnover, suggesting that plantations are complementary habitats for some species, but cannot be a substitute habitat for all native forest species. Furthermore, edge effects had a strong impact on the composition of native communities, such that certain species were only present in the interior of the native habitat. Synthesis and applications. Large areas of native vegetation, where the interior remains intact, are essential to preserve species that are susceptible to edge effects and that cannot occupy other habitat types. Creating straight instead of winding edges could decrease the impact that plantations have on native forests. Furthermore, increasing the representativeness of native plant communities in exotic plantation forests would cascade up to higher consumer trophic levels, considerably increasing the conservation value of these commercial stands.

吕梁山森林群落草本层植物物种多样性的空间格局及其对模拟增温的响应

PDF HTML阅读 XML下载 导出引用 引用提醒 吕梁山森林群落草本层植物物种多样性的空间格局及其对模拟增温的响应 DOI: 10.5846/stxb201803300700 作者: 作者单位: 太原师范学院地理科学学院,太原师范学院地理科学学院,太原师范学院地理科学学院,太原师范学院地理科学学院 作者简介: 通讯作者: 中图分类号: 基金项目: 山西省应用基础研究计划项目（2016021136）；山西省高等学校重点学科建设项目（晋教研函〔2016〕4号）；山西省高等学校科技创新项目（晋教科函〔2016〕4号） Spatial pattern of herbaceous plant species diversity and its changes due to simulated warming in the forest community of the Luliang Mountains Author: Affiliation: Taiyuan Normal University,Taiyuan Normal University,Taiyuan Normal University,Taiyuan Normal University Fund Project: 摘要 | 图/表 | 访问统计 | 参考文献 | 相似文献 | 引证文献 | 资源附件 | 文章评论 摘要:为研究气候变暖背景下森林群落草本层植物物种多样性对温度升高的响应及其随海拔、纬度的空间分布格局，按照纬度梯度选择吕梁山系北段的管涔山和南段的五鹿山为研究区，并在每个山地的不同海拔梯度（高、中、低）分别设置对照（CK）、低度增温（OTC1）和高度增温（OTC2）3种试验样地。于2017年植被生长季对植物多度、频度、盖度、高度进行调查，计算物种多样性指数（Simpson指数、Shannon指数、Pielou指数、Patrick指数）。结果表明：（1）吕梁山森林群落草本层植物物种多样性随海拔呈"v型"变化格局，即在中间海拔梯度处最低，且海拔梯度对各多样性指数的影响均达到极显著水平（P < 0.01）。（2）物种多样性随纬度升高呈递增趋势（P > 0.05），即较高纬度山地具有较高的物种多样性。（3）物种多样性随温度升高整体呈递减趋势（P > 0.05），即温度升高可抑制林下草本层植物物种多样性。（4）在增温处理下，五鹿山草本植物的Simpson指数、Shannon指数和Patrick指数呈递减趋势，Pielou指数先降低后升高；管涔山草本植物的Simpson指数、Shannon指数和Pielou指数先增加后减小，Patrick指数呈递增趋势。整体来说，在吕梁山较低海拔，持续增温会使物种多样性降低；在中等海拔，物种多样性随温度升高呈现先下降后上升的变化趋势；在较高海拔，适度增温可提高物种多样性，持续增温则抑制多样性。因此，增温对吕梁山森林群落草本植物物种多样性的影响随海拔升高整体呈下降趋势。 Abstract:The objective of this study was to investigate the species diversity of herbaceous plant communities in forests regarding changes due to temperature increases, and the spatial distribution pattern at varying elevations and latitudes in a warming climate. Adhering to a latitudinal gradient, Guancen Mountain in the northern section of the Luliang Mountains and Wulu Mountain in the southern section of the Luliang Mountains were selected as study areas. Three plot categories [control, low temperature increase (OTC1), and high temperature increase (OTC2)]were set at different altitudes (high, medium, and low) in each of the study areas. During the vegetation growth season in 2017, plant diversity, frequency, coverage, and height were investigated to calculate species diversity indices (Simpson index, Shannon index, Pielou index, and Patrick index). An S-THB-M008 air temperature probe with an RS3-B radiation shield was set up at a height of 20 cm above ground level to measure ambient temperature. Our data revealed that the herbaceous species diversity in the forest community of the Luliang Mountains exhibited a "v-shaped" pattern depending on elevation (i.e., the lowest species diversity was found in the middle elevation). Altitude effects were most strongly correlated with the Simpson index (R2=0.1711), and the effects of the altitude gradient on diversity indices were highly significant (P < 0.01). Additionally, species diversity increased with latitude, and latitude effects were most correlated with the Simpson index (R2=0.1221, P > 0.05). This is followed by the Shannon index (R2=0.0807), the Pielou index (R2=0.0785), and the Patrick index (R2=0.0382). In response to increasing temperatures, each diversity index initially decreased, but then increased, with an overall downward trend (P > 0.05). Thus, increasing temperatures may decrease the plant species diversity of herbaceous layers under the forest canopy. Among species diversity indices, the Simpson index produced the strongest correlation of temperature effects (R2=0.3374, P > 0.05). Moreover, under simulated warming conditions, the Simpson index, Shannon index, and Patrick index of herbaceous species in Wulu Mountain exhibited a decreasing trend. In contrast, the Pielou index increases first and then decreases. In comparison, the Simpson index, Shannon index, and Pielou index of herbaceous plants in Guancen Mountain increased at first and then decreased, whereas the Patrick index increased. Overall, continued warming will decrease species diversity at lower altitudes of the Luliang Mountains. At moderate altitudes, species diversity will first decrease and then increase with rising temperatures. At relatively high altitudes, moderate warming will increase species diversity, but continued warming will negatively affect species diversity. Moreover, the effect of the altitude gradient on plant species diversity in the understory herbaceous layer was highly significant (P < 0.01). In Guancen Mountain, different treatments showed a significant effect on the Pielou Index (P<0.05). However, in other plots, different treatments did not significantly affect plant species diversity. The diversity of plant species was least affected by the combination of high gradients and different treatments. Therefore, the effects of warming on the diversity of herbaceous species in the forest community of the Luliang Mountains exhibit a decreasing trend with elevation. 参考文献 相似文献 引证文献

Composition and Diversity of Soil Fungi in Dipterocarpaceae-Dominated Seasonal Tropical Forests in Thailand.

Although fungi play essential roles in nutrient cycles and plant growth in forest ecosystems, limited information is currently available on the community compositions of soil fungi in tropical forests. Few studies have examined fungal community structures in seasonal tropical forests, in which forest fires potentially have a large impact on above- and belowground community processes. Based on high-throughput sequencing technologies, we herein examined the diversity and community structures of soil fungi in dry seasonal tropical forests in Sakaerat, northeast Thailand. We found that fungal community compositions diverged among dry evergreen, dry deciduous, and fire-protected dry deciduous forests within the region. Although tree species diversity did not positively correlate with soil fungal diversity, the coverage of an understory bamboo species (Vietnamosasa pusilla) showed a strong relationship with fungal community structures. Our community ecological analysis also yielded a list of fungi showing habitat preferences for either of the neighboring evergreen and deciduous forests in Sakaerat. The present results provide a basis for managing soil fungal communities and aboveground plant communities in seasonal tropical forests in Southeast Asia.

Lack of herbaceous layer community recovery in postagricultural forests across three physiographic regions of New York

Agricultural land-use legacies remain persistent determinants of plant-community composition, despite extended periods of recovery in postagricultural forests of New York. We surveyed the composition of vascular plant species for 33 paired residual (unconverted) and secondary (postagricultural) forest sites across three physiographic regions in New York to assess the recovery of residual forest species in secondary successional stands. There were 169 vascular plant species recorded among the 33 study sites. The residual stands exhibited slightly greater mean (± SE) species richness (26.8 ± 1.7 species per site) than secondary-interior (21.4 ± 1.2, P = 0.001) and secondary-edge (24.1 ± 1.6, P = 0.02) zones. Plant communities differed across the three physiographic regions (P = 0.001) and by stand history within regions (P = 0.004). Of the vascular plant species occurring at our sites, 22 (13%) were indicators of residual forest stands and 27 (16%) were indicators of secondary, postagricultural forest stands. Within 10 to 25 m of the historic field-forest ecotones, the relative frequencies of many residual woodland indicator species fell to 0–20% of the maxima they attained in the residual stands. Ant-dispersed (myrmecochorous) taxa represented 23% of residual and 0% of secondary forest indicators and exhibited lower migration rates (P < 0.001) than plants possessing other diaspore dispersal modes (anemochory, zoochory, barochory). In addition to plant dispersal mode, we found pH and forest-floor depth to be important determinants of plant species. Our results indicate that impoverishment of plant communities in postagricultural forests represent a regionally pervasive phenomenon with important resource management implications in the eastern USA. Residual woodlands remain important source populations for recovery of herbaceous species in postagricultural landscapes. However, given the slow historic recovery rates that we and others have observed in postagricultural secondary forests, in addition to other contemporary factors potentially inhibiting dispersal and establishment (e.g., herbivory, pollinator disruptions, invasive species), it seems likely that active restoration efforts are needed to promote full recovery of diverse, native temperate-forest herb communities.

Vegetation structure and species composition variation of roadside slopes in Sichuan Basin, China

Sichuan Basin in southwestern China is a region of great conservation concern, yet little is known about the influence of edaphic factors on plant community dynamics of disturbed areas. We used multivariate analyses to identify differences in vegetation structure (i.e., tree, shrub, forb, and graminoid) and species composition between sandstone and shale substrates across 13 successional forest plant communities that varied in soil depth and soil texture. Vegetation structure did not differ between substrates (P >0.05), but plant community composition varied significantly (P = 0.0017). In addition, six indicator species were identified, including two native perennial grasses; namely, Imperata cylindrica for intermediate soil depths (20-30 cm) on sandstone substrate (P = 0.016) and Miscanthus sinensis for greater soil depths ( > 30 cm) on sandstone (P = 0.012) as well as on intermediate soil depths (20-30 cm) on shale substrate (P = 0.0002). Imperata cylindrica and M. sinensis were also the most dominant perennial grass species on sandstone (15.6 ± 5.3% cover) and shale (12.3 ± 4.9% cover), respectively. These patterns provide insights into species interactions and successional dynamics of roadside slopes, and offer guidance when choosing suitable species for future restoration projects in the Sichuan Basin.

Resource Availability, Propagule Supply, and Effect of Nonnative Ungulate Herbivores onSenecio madagascariensisInvasion

Nonnative invasive herbivores can create complex biotic interactions by differentially feeding on native and nonnative invasive plant species. The herbivores may act as enemies of nonnative plants and prevent them from becoming invasive, or they may facilitate invasion by having a greater negative impact on native plants compared with nonnative plants. It is also possible that within the same ecosystem nonnative herbivores could either facilitate or inhibit invasion under different abiotic or biotic conditions. In this study we experimentally investigated how abiotic (soil nutrients) and biotic (propagule density) conditions influence the effect of invasive generalist herbivores on Senecio madagascariensis, an invasive plant species in Hawaiian dry forest plant communities. We used fenced exclosures to manipulate presence or absence of invasive ungulates (feral goats and sheep), and we used seed addition to manipulate propagule supply of S. madagascariensis. The experiment was replicated in a recently burned and an unburned site to examine how a resource pulse following fire may alter plant-herbivore interactions. There were very few seeds of S. madagascariensis in the seed rain of both sites, and recruitment was four times higher when seeds were experimentally added, suggesting that S. madagascariensis is dispersal limited in this area. Recruitment of S. madagascariensis was five times higher in the burned site compared to the unburned site, suggesting that increased resources promote recruitment. Recruitment was three times higher when herbivores were present compared to when they were excluded, but plants were much smaller when herbivores were present. We conclude that herbivores can alter S. madagascariensis recruitment, even during dry conditions, and that propagule availability influences where S. madagascariensis can become established.

Distribution of Lichen Species of the Genus Lepraria in the Knyszyn Forest (Ne Poland) in Different Forest Plant Communities

Abstract The aim of the study was to evaluate the distribution of lichen species of the genus Lepraria in Knyszyn Forest (NE Poland) to different forest plant communities. Six species of Lepraria [L. eburnea J. R. Laundon, L. elobata Tønsberg, L. incana (L.) Ach., L. jackii Tønsberg, L. lobificans Nyl. and L. vouaxii (Hue) R. C. Harris] recorded from Knyszyn Forest. Lepraria eburnea is a new species for the studied area. The most common species were Lepraria incana and L. lobificans. Among the studied forest communities the richest in species (5 species of Lepraria) were oak-hornbeam forest (Tilio-Carpinetum), and the least species-rich (2 species) were maple-linden slope forest (Aceri-Tilietum), alder carr (Carici elongatae-Alnetum) and spruce forest (Sphagno girgensohnii-Piceetum). The richest lichen diversity in the Knyszyn Forest was found on deciduous trees such as Carpinus betulus L. and Quercus robur L. (4 species), Tilia cordata Mill. (3 spp.), and conifers such as Picea abies (L.) H. Karst. and Pinus sylvestris L. (3 spp.).

Vascular Flora of E. C. Hafer Park, Edmond, Oklahoma

E. C. Hafer Park is located on the western edge of the Cross Timbers ecoregion, in central Oklahoma within the City of Edmond. The park contains post oak-blackjack oak forest, tallgrass prairie, riparian forest, and areas developed for recreational activities. A vascular plant inventory conducted during 2013, 2015, 2016, and 2017 yielded 270 species in 190 genera and 65 families. The largest families were the Asteraceae (46 species), Poaceae (42), and Fabaceae (27). There were 96 annuals, four biennials, and 170 perennials. Sixty species (22.2%) were not native to the United States. No rare species currently being tracked by the Oklahoma Natural Heritage Inventory were present. Compared to floristic inventories for other sites of similar size in Oklahoma, Hafer Park has a relatively high number of species. However, it also has a relatively high percentage of exotic species from other continents, some of which are invasive and are threatening the native forest, grassland, and riparian plant communities.

Trophic conditions of forest soils of the Pieniny National Park, southern Poland

Abstract The primary objective of this study was to characterise the edaphic conditions of forest areas in the Pieniny National Park (PNP), and to describe the dependencies between properties of forest soils and types of forest plant communities. The “Soil Trophic Index” (SIGg) for mountainous areas was applied. The evaluation of the trophism for 74 forest monitoring employed the soil trophic index for mountainous areas SIGg or SIGgo. Plant communities in the forest monitoring areas were classified according to the Braun-Blanquet’s phytosociological method. Soils of PNP present in the forest monitoring areas were mostly classified as eutrophic brown soils (72.9%), rendzinas (10.8%), brown rendzinas (5.41%), and rubble initial soils (5.41%). Pararendzinas, dystrophic brown soils, and gley soils were less common (total below 5.5%). In the forest monitoring areas of PNP, eutrophic soils predominate over mesotrophic soils. High SIGg index of the soils is caused by high values of acidity and nitrogen content. The Carpathian beech forest Dentario glandulosae-Fagetum and thermophilic beech forest Carici albae-Fagetum associations are characterised by high naturalness and compatibility of theoretical habitats. The soils of the Carpathian fir forest Dentario glandulosae-Fagetum abietetosum subcommunity is characterised by a higher share of silt and clay particles and lower acidity as compared to the Carpathian beech forest Dentario glandulosae-Fagetum typicum subcommunity. The soils of the forest monitoring areas in PNP stand out in terms of their fertility against forest soils in other mountainous areas in Poland.

Ungulates increase forest plant species richness to the benefit of non-forest specialists.

Large wild ungulates are a major biotic factor shaping plant communities. They influence species abundance and occurrence directly by herbivory and plant dispersal, or indirectly by modifying plant-plant interactions and through soil disturbance. In forest ecosystems, researchers' attention has been mainly focused on deer overabundance. Far less is known about the effects on understory plant dynamics and diversity of wild ungulates where their abundance is maintained at lower levels to mitigate impacts on tree regeneration. We used vegetation data collected over 10years on 82 pairs of exclosure (excluding ungulates) and control plots located in a nation-wide forest monitoring network (Renecofor). We report the effects of ungulate exclusion on (i) plant species richness and ecological characteristics, (ii) and cover percentage of herbaceous and shrub layers. We also analyzed the response of these variables along gradients of ungulate abundance, based on hunting statistics, for wild boar (Sus scrofa), red deer (Cervus elaphus) and roe deer (Capreolus capreolus). Outside the exclosures, forest ungulates maintained higher species richness in the herbaceous layer (+15%), while the shrub layer was 17% less rich, and the plant communities became more light-demanding. Inside the exclosures, shrub cover increased, often to the benefit of bramble (Rubus fruticosus agg.). Ungulates tend to favour ruderal, hemerobic, epizoochorous and non-forest species. Among plots, the magnitude of vegetation changes was proportional to deer abundance. We conclude that ungulates, through the control of the shrub layer, indirectly increase herbaceous plant species richness by increasing light reaching the ground. However, this increase is detrimental to the peculiarity of forest plant communities and contributes to a landscape-level biotic homogenization. Even at population density levels considered to be harmless for overall plantspecies richness, ungulates remain a conservation issue for plant community composition.

Distribución espacial y análisis ambiental de la flora vascular de los Pirineos

La reciente publicación web del Atlas de la flora vascular de los Pirineos permite ahora delimitar la diversidad florística de la cordillera y analizar su distribución territorial y algunas afinidades ambientales con el fin de contribuir a su caracterización ecológica y a su conservación. La flora vascular de los Pirineos reúne 3.652 plantas vasculares autóctonas, incluyendo especies y subespecies, lo que sitúa a la cordillera como el segundo núcleo de diversidad florística en Europa, tras los Alpes. Entre los seis sectores geográficos considerados, los que albergan mayor riqueza de plantas son el Central-Sur (76% del total) y los dos orientales (ambos con el 75%). En el gradiente altitudinal, el piso montano es el que alberga mayor número de taxones (87% del total). Respecto a la corología, el 32% de la flora pirenaica son plantas eurosiberianas, el 29% mediterráneas, las orófitas alpinas y boreoalpinas son el 12,6% y los endemismos un 5%. Por sus formas biológicas, predominan los hemicriptófitos (40%) y los terófitos (20,4%). Conforme se asciende en altitud, aumentan los caméfitos y disminuyen los terófitos. Por su preferencia edáfica, un 35% de la flora es calcícola y un 21% silicícola. En cuanto a la representación por hábitats, cerca del 30% de las plantas viven en pastos, el 16% en humedales, los ambientes rocosos, bosques, matorrales y comunidades ruderales albergan un número similar de plantas (entre el 12 y 13% cada uno). Por último, teniendo en cuenta la naturalidad de los hábitats, el 47% de las plantas vive en los de alta o muy alta naturalidad, aunque cerca de una cuarta parte se encuentra en los más humanizados.

Litter Accumulation and Nutrient Content of Roadside Plant Communities in Sichuan Basin, China.

It is widely recognized that feedbacks exist between plant litter and plant community species composition, but this relationship is difficult to interpret over heterogeneous conditions typical of modified environments such as roadways. Given the need to expedite natural recovery of disturbed areas through restoration interventions, we characterized litter accumulation and nutrient content (i.e., organic carbon, total N, and P) and quantified their association with key plant species. Plant species cover and litter characteristics were sampled at 18 successional forest plant communities along major roadways in Sichuan Basin, western China. Variation in litter across communities was assessed with principal component analysis (PCA) and species with the highest correlation to PCA axes were determined with Pearson’s r coefficients. Plant communities with the longest time since road construction (i.e., 70 years) were distinctly different in litter total N and organic carbon compared to plant communities with a shorter disturbance history. We encountered 59 plant species across sampling plots, but only four rare species (i.e., frequency < 5) were strongly correlated with litter characteristics (p < 0.01); none of which were the most abundant where they occurred. These results highlight the importance of site-specific factors (i.e., geographic location, disturbance age) regulating plant litter across heavily disturbed landscapes and how litter characteristics and rare plant species are correlated.

Effects of an invasive shrub, Lonicera maackii, and a generalist herbivore, white-tailed deer, on forest floor plant community composition

Both overabundant ungulates and invasive shrubs negatively impact forest floor plants, but few studies have investigated their interaction. We tested for direct effects and interactions of white-tailed deer, Odocoileus virginianus, and the invasive shrub, Lonicera maackii, on forest floor plant richness and composition in five sites in southwest Ohio. In each site a deer exclosure and an unfenced plot (each 20×20m) were established in 2010; in half of each plot all L. maackii was removed. Each spring and summer, 2011–2014, percent cover of each plant species in 50×20cm subplots was recorded.Herb layer species richness was greater where L. maackii was removed, and this effect tended to be stronger where deer were excluded. Species composition in the spring was not affected by treatments, whereas summer species composition (in one year) was affected by L. maackii treatment. Cover of graminoids, spring herbs, and vines were lower where L. maackii was intact, whereas cover of shrubs and tree seedlings were lower, and cover of bare ground higher, where deer had access.Our findings reveal that deer and L. maackii negatively impact different components of the forest herb layer. However, the combined effects on species richness tended to be antagonistic (less than additive), possibly due to deer browse reducing the cover of this invasive shrub. This suggests that the diversity of the herb layer will be enhanced more by both removal of invasive shrubs and reduction of the deer population than by either management action alone.

Vascular plant species richness and composition in two types of post‐cultivation tropical secondary forest

AbstractQuestionHow are plant communities in forests regenerating on post‐cultivation land structured along environmental gradients, landscape context and past land use? We investigated this for two types of post‐agricultural fates: plantations abandoned with trees intact (abandoned land forest) versus land that was cleared and left to regenerate into a forest (waste woodland).LocationThe tropical city‐state of Singapore, Southeast Asia.MethodsFive 20 m × 20 m plots were surveyed for vascular plants in each of 11 patches of abandoned land forest and nine patches of waste woodland. For each plot, we estimated soil nutrient levels (N, K, P), canopy cover, leaf litter depth, distance to old‐growth forest and the size of the forest patch.ResultsFor both forest types, increasing leaf litter and distance to old‐growth forest is associated with lower species richness. Increasing soil N in abandoned land forest and increasing soil K in waste woodland is associated with lower total and native species richness, but not exotic species richness. Overall community composition is correlated with leaf litter, canopy cover, soil P and K and distance to old‐growth forest.ConclusionsDifferent forms of land abandonment resulted in different successional trajectories that led to separate sets of environmental drivers of community patterns. Restoring such degraded forms of vegetation to native‐rich communities may require management of soil nutrient levels and enrichment planting.