Woody Pasture Research Articles

Predicting the field host-range of Leptinotarsa undecimlineata: A candidate biocontrol agent for Solanum torvum in Vanuatu

The host specificity of Leptinotarsa undecimlineata Stål, a candidate biocontrol agent for Solanum torvum Sw. (turkey berry) a woody pasture weed in Vanuatu was investigated. In no-choice tests, adult L. undecimlineata beetles fed and oviposited on eggplant (Solanum melongena L.) plants, which also supported development of first instar L. undecimlineata larvae through to adult. A systematic review of field host records indicated that L. undecimlineata has never been reported to attack S. melongena throughout most of its native range in Mexico, the Antilles and Colombia, although minor and infrequent spillover attack has been observed in Central America. Choice oviposition, ‘multiple generation’ (continuation) tests, and the relative performance risk score approach (updated to use Firth’s bias reduced logistic regressions) were used to investigate the potential risk posed to S. melongena should L. undecimlineata be released in Vanuatu. The relative risk score approach was inconclusive, indicating a low but not zero risk of S. melongena being a persistent field host for both choice and no-choice tests. In contrast, the multiple generation tests demonstrated that L. undecimlineata cannot persist on S. melongena. Adult feeding was lower and significantly fewer eggs were laid on S. melongena compared to S. torvum in no-choice adult feeding and oviposition tests. The combination of tests used provided an explanation why only minor and infrequent spillover attack on S. melongena has been reported in parts of the native range of L. undecimlineata. We conclude that L. undecimlineata poses a very low risk to S. melongena should it be introduced into Vanuatu. However, the relative performance risk score approach requires further analyses using larger datasets to investigate the potential for threshold scores to be used to reliably predict risk.

Clonal Diversity and Fine-Scale Genetic Structure of a Keystone Species: Ilex aquifolium

Resprouting species, such as English holly (Ilex aquifolium L.), can be severely affected by long-lasting forest management. In the present study, the clonal and fine-scale spatial genetic structure (FSGS) of English holly are evaluated in a sub-Mediterranean mixed forest of Central Spain, where this species was subjected to different and intense human interventions for centuries, including coppicing in dense structures and in open woody pastures. Using seven microsatellite loci, we assessed the contribution of clonal and sexual reproduction to the diversity of holly in both areas and the fine-scale genetic structure was evaluated. For the dense coppiced area, the results showed high clonal diversity derived mainly from stem resprouting. Stems were separated an average of 3 m and up to 10 m, and dense aggregations of stems sometimes included various genotypes. The results also showed recent seed recruitment leading to small unique and isolated genotypes. Furthermore, FSGS was detected at close distances as being stronger in the coppiced area than in the open woody pasture area, especially for individuals of greater diameter at breast height. The results obtained suggest that current management strategies are not negatively affecting the genetic diversity of this species.

The effect of topography on the distribution of rodent nests in the enclose and non-enclosed of pistachio forest of Khajeh Kalat in northeast of Iran

The order Rodentia is the largest among other groups of mammals in terms of the number of species and number of individuals and is widely seen in different types of habitats. Various factors affect the spatial distribution of these animals. In this study, according to the same conditions in the two areas in terms of topography, soil, and the vegetation type, the distribution of rodent nests in the enclosed and non-enclosed regions of woody pasture in the pistachio forest pasture of Khajeh Kalat in Khorasan Razavi province of Iran has been studied. For this purpose, sample plots with the variable region that had at least 15 trees were used. Inside of each sample plot and under the crown of any tree, rodent nests were identified and counted. Finally, the data obtained from the total sample plots have been analyzed. The results showed that the number of rodent nests in the two regions was significantly at 99% confidence level related to each other, as well as in elevation, slope and aspect was significantly at 99% confidence. Rodent nest distribution is also related to the soil characteristics of the region, and rodents prefer deeper, more fertile soils with a lighter texture and better drainage so that they can dig in easily and rain does not flood their nests. Slope also has an effective role in runoff, infiltration, flood intensity, erodibility, and sedimentation which are not ineffective in rodent release. The north and south aspect are more suitable for rodents due to their moisture and shading and better soil for nesting, and therefore the number of nests in the north and south aspects is higher than in another aspect. Of course, other factors also affect rodent distribution, including ecological relationships, environmental variables between species, and animals.

Do large herbivores maintain open habitats in temperate forests?

In recent decades, grazing by wild and domestic ungulates has become a strategy for conservation management to restore or maintain open landscapes. One of the species playing an increasing role in ecological restoration is the European bison – the largest terrestrial mammal in Europe. We studied the impact of this large herbivore and other ungulates (moose, red deer, and roe deer) on tree encroachment in open habitats in the Białowieża Primeval Forest (Poland). On 30 study plots located in meadows, we measured crown volume and the density of woody vegetation and monitored visitation and behavior of ungulates with the use of camera traps. The mean visitation rate to meadows by European bison was 0.11 ind./day/plot, and 0.22 ind./day/plot by other ungulates. The duration of foraging was significantly higher in European bison (55.8 s) than in other ungulates (16.3 s). The density of woody vegetation on meadows varied from 13 to 6213ind./ha and the crown volume from 0.6 to 1145 m3/ha. We found that increased visitation by European bison resulted in a significant reduction in the density and volume of woody vegetation in meadows. The reducing effect on woody vegetation was over eight times higher in frequently visited plots when compared to unvisited plots – the density of woody vegetation decreased from 879 to 101 saplings/ha, while the crown volume declined from 295 to 35 m3/ha. In addition, the density of woody vegetation was related to the level of meadow openness. Less open (smaller) meadows had a significantly higher density of woody vegetation than meadows characterized by high openness. Combined visitation by other ungulates did not affect either the volume or density of woody vegetation. The most plausible mechanism of observed patterns can be a remarkably higher foraging activity in meadows by bison in comparison to other ungulates. As a consequence, European bison, being adapted to open habitats, can effectively reduce the growth of tree seedlings and limit tree encroachment at the initial stages of forest succession. Thus, populations of this wild herbivore can play a role in the restoration or maintenance of open habitats and woody pastures that serve as an important foraging ground for bison in suboptimal forests, where populations of these herbivores were restored.

Contrasting multi-taxa functional diversity patterns along vegetation structure gradients of woody pastures

Woody pastures represent keystone habitats for biodiversity in agricultural landscapes, contributing to increased resource availability, landscape heterogeneity and structural variability. High taxonomic diversity is closely linked to vegetation structure in woody pastures, but examining functional characteristics of species assemblages can shed more light on the ecological mechanisms driving divergent responses to habitat characteristics and help guide good management practices. To this end, we use a multi-taxa approach to investigate how plant, bat and bird taxonomic and functional diversity are affected by pasture tree and shrub density, structural complexity and proximate forest cover in southern Sweden. In particular, we use a trait exclusion approach to estimate the sensitivity of diversity-environment relationships to specific traits. We found little congruence between corresponding diversity metrics across taxa. Bird species richness responded stronger to environmental variables than functional diversity metrics, whereas the functional response to the environment was stronger than the taxonomic response among plants and bats. While increasing tree densities increased the taxonomic diversity of all three taxa, a simultaneous functional response was only evident for plants. Contrasting measures of vegetation structure affected different aspects of functional diversity across taxa, driven by different traits. For plants and birds, traits linked to resource use contributed particularly to the functional response, whereas body mass had stronger influence on bat functional diversity metrics. Multi-taxa functional approaches are essential to understand the effects of woody pasture structural attributes on biodiversity, and ultimately inform management guidelines to preserve the biological values in woody pastures.

The importance of trees for woody pasture bird diversity and effects of the European Union's tree density policy

Summary Recent reforms in the Common Agricultural Policy aim for a greening of the subsidy system with potential improvements for biodiversity conservation. As part of that process, the tree density limit for pastures to qualify for European Union subsidies has been increased from 50 to 100 trees per hectare. However, recent studies show that the high biodiversity values of these habitats may be threatened by these limits, highlighting the need for policy improvements. Still, little is known about the direct effects of tree density limitations on bird communities in woody pastures. We investigated how bird diversity and species composition are affected by tree density in 49 Swedish woody pastures along a gradient of 4–214 trees per hectare. We recorded bird communities, tree density and stand structure estimates in the field and estimated forest cover in the surrounding landscape from aerial photos. Using generalised additive models and redundancy analysis, we analysed how bird territorial species richness, bird abundance and species composition are affected by tree density, taking into account other local and landscape scale explanatory variables. Tree density had a significant positive effect on bird species richness at low tree densities and species richness saturated at approximately 50 trees per hectare. Shrub density had a significant positive linear effect on both bird species richness and abundance. Tree and shrub density were also the major drivers of bird community composition, with secondary effects of tree species diversity and landscape forest cover. Policy implications. Our results show that tree density is not the limiting factor, but rather a driver of bird diversity and species composition in woody pastures and that tree density limits may fail to capture the whole range of biological values. To improve policy recommendations, we therefore stress the importance of considering additional social–ecological drivers associated to management quality, e.g. taking into account moral and cultural motivations among farmers, to preserve biodiversity in woody pastures.

Diversité Floristique Et Usages Des Ligneux Le Long Des Couloirs De Transhumance Dans La Commune De Savè Au Centre Bénin

The vegetation cover of the District of Savè is subject to continuous pressure linked inter alia to the cutting of wood, agriculture and livestock through transhumance. Thus, forage seedlings are regularly used mainly during the dry season by transhumant herds. In this context, the characterization of woody pastures and the study of the uses of its timber by the local populations is a major imperative for their preservation and sustainable management. To this end, socio-economic surveys were carried out among the stakeholders involved in the use of these plant resources. The phytosociological surveys (29 plots of 30 m * 30 m) were carried out using the sigmatite method of Braum blanquet. Different indices have been calculated. The graph of the raw and weighted spectra was carried out. The characterization of the structure of the pasture shows a predominance of the individuals of circumference of between 30 and 50 cm. Mesophanerophytes are the most abundant and dominant forms of life, while chronologically Sudanese and Sudano-Zambeze species are the most represented. The most represented families are the combretaceae the leguminoseae. The Shannon diversity index varies from 3.21 to 3.95 bits and the Piélou equitability from 0.72 to 0.83 from one pasture to another. Three (3) types of pasture were identified along transhumance corridors. Namely: the pasture at Lannea velutina and Bridelia ferruginea; Pasture in Trichilia emetica and Annona senegalensis and grazing in Pteleopsis suberosa and Pericopsis laxiflora. This study shows that the environmental conditions favor the installation of several species along the transhumance corridors. The uses of forage resources, such as pruning for feeding livestock, charcoal making, fuelwood research, particularly in transhumance corridors, are not likely to Conservations

Differentiating the geographical origin of Tunisian indigenous lamb using stable isotope ratio and fatty acid content

The efficacy of isotope ratio mass spectrometry (IRMS) in tracing lamb production systems was investigated for four farming systems in the Tunisian North-West: Ain Draham and Fernana, characterised by woody pasture, and Amdoun and Joumine, characterised by herbaceous pasture. Mixed breed lambs aged 3.5–5 months were reared under semi-extensive and extensive systems. Samples of Longissimus dorsi muscle were taken from eight lambs for each farming system for stable IR assessment of the five main bio-elements in the protein and fat fractions of lamb and for fatty acid (FA) determination. Using partial least squares discriminant analysis (PLS-DA) the IR profiles of Tunisian lamb types allowed correct assignment of the training meat samples to the area of origin. Inclusion of the FA profile in the classification model slightly improved its evaluation performance for the individual farming systems; the average accuracy increased by 2%–94%. However, the differences between samples were not sufficiently wide to be validated by an external set of samples including 10 Italian lamb types. A broader scale geographical signature discriminating lambs from the Amdoun area, the rest of north-west Tunisia and Italy appeared to be workable, although some foreign lamb types from neighbouring Mediterranean regions such as Sicily were misclassified as Tunisian.

Governing nature by numbers — EU subsidy regulations do not capture the unique values of woody pastures

A vast majority of European farmers are dependent on EU subsidies, which makes subsidy regulations through the Common Agricultural Policy (CAP) powerful tools in shaping agricultural landscapes. Unfortunately, steering recommendations are sometimes arbitrary, like in the case of pasture management, where 50 trees per hectare constitute an upper limit to qualify for subsidies. Although pasture biodiversity is well studied and the core of many CAP conservation programmes, it is seldom studied as direct effects of subsidy systems. In this paper, we examine plant diversity in relation to the impact of subsidy systems in Swedish woody pastures along a gradient from 3 to 214 trees per hectare. We selected 64 sites where we recorded vascular plants, soil properties and canopy cover. We found a general increase in γ- and β-diversity along the gradient, whereas α-diversity and the number of grassland specialists remained indifferent along the gradient. Additionally, tree density, organic content and C:N-ratio were the strongest predictors of species composition. Hence, when CAP regulations encourage tree cutting for pastures to qualify for subsidies there is risk of homogenisation of EU grasslands, leading to decreased γ- and β-diversity. If a general target for the subsidies is to increase biodiversity, there is need to scrutinise these regulation details to preserve the high values of woody pastures. We argue that habitat variation, species diversity and low intensity management, rather than a specific number of trees, should be the main incentives for financial support to preserve biodiversity.

Land use intensity trajectories on Amazonian pastures derived from Landsat time series

Monitoring changes in land use intensity of grazing systems in the Amazon is an important prerequisite to study the complex political and socio-economic forces driving Amazonian deforestation. Remote sensing offers the potential to map pasture vegetation over large areas, but mapping pasture conditions consistently through time is not a trivial task because of seasonal changes associated with phenology and data gaps from clouds and cloud shadows. In this study, we tested spectral-temporal metrics derived from intra-annual Landsat time series to distinguish between grass-dominated and woody pastures. The abundance of woody vegetation on pastures is an indicator for management intensity, since the duration and intensity of land use steer secondary succession rates, apart from climate and soil conditions. We used the developed Landsat-based metrics to analyze pasture intensity trajectories between 1985 and 2012 in Novo Progresso, Brazil, finding that woody vegetation cover generally decreased after four to ten years of grazing activity. Pastures established in the 80s and early 90s showed a higher fraction of woody vegetation during their initial land use history than pastures established in the early 2000s. Historic intensity trajectories suggested a trend towards more intensive land use in the last decade, which aligns well with regional environmental policies and market dynamics. This study demonstrates the potential of dense Landsat time series to monitor land-use intensification on Amazonian pastures.

Structural diversity, its components and regenerating capacity of lesser Himalayan forests vegetation of Nikyal valley District Kotli (A.K), Pakistan

ObjectiveTo report the patterns of species diversity, and regenerating capacity in the forest of Nikyal valley in relation to environmental variables and underlying anthropogenic influence. MethodsA study area was selected in a traditionally managed mountain woody pasture during July 2012 to June 2013. The area was sampled by quadrat method. The quadrats were laid down at regular intervals of 150 m. The size of quadrats was kept 10×10, 5×5 and 1×1 m2 for trees, shrubs and herbs respectively. Density, frequency and cover were recorded. Importance value index of each plant species was calculated and plant communities were named after the plant species having the highest IV. Then diversity, its components and regenerating capacity were calculated with their formulas. ResultsShannon's diversity ranged from 2.75 to 3.31, Simpson's diversity, 0.90 to 0.95; Menhinick's diversity, 0.83 to 1.19; evenness, 0.41 to 0.65; species richness, 4.89 to 6.08 and maturity index, 30 to 44 species distribution pattern. Diversity values were similar to the other Himalayan forests. Pinus roxburghaii was the only regenerating species whereas the remaining four tree species including Qurecus dilatata regenerate up to 100 cm; they are at extreme risk of elimination due to anthropogenic factors. ConclusionsNikyal valley is under severe deforestation pressure for fuel and timber value. There is an urgent need to promote the ethics among the people that improvement and conservation of natural resources are critical for land and soil management.