Woodland networks in a changing climate: Threats from land use change

Landscape adaptation to climate change requires policies that facilitate species dispersal, to counteract the effects of fragmentation and allow tracking of a species’ ‘climatic niche’. Expanding existing ecological networks is often proposed as a measure to maintain functional connectivity for forest species in multi-functional landscapes.In the next decades, however, such networks will be threatened by climate change through its effects on land use change, as global drivers are likely to have an increasing influence on national land use policy. Evaluation of indirect effects of climate change, on habitat networks, mediated by land use change, is therefore needed. We used an approach integrating climate, soil properties, and landscape resistance to dispersal, the latter estimated using Circuit Theory, to evaluate the vulnerability to land use change of forest habitat networks in Scotland, given two scenarios of land use change. In Scotland a combination of high food prices and improved land capability for agriculture could lead to decreased landscape connectivity for woodland species, especially in the East and South, with potentially large trade-offs between agriculture and woodland connectivity in the case of loss of woodland on prime agricultural land. We suggest that planning of ecological networks needs to account for future land use change. Adaptation and mitigation strategies across multiple sectors should be reconciled. Woodland networks will benefit from minimising creation of new woodlands on future prime agricultural land, the protection of existing patches, and the creation of wide-scale dispersal pathways along climatic gradients, i.e. in the N–S and E–W directions.     

Agricultural policies and the capitalist State

The paper examines the social contradictions generated by patterns of reproduction of accumulation of capital, social legitimation and by present agricultural policies fostered by the State. Through a scrutiny of the role of the State in capitalism it is argued that agricultural overproduction, the widening of the gap between small and large farms, the fiscal crisis of the State associated with agricultural programs and waste of resources are the outcomes of an attempt on the part of the State to promote simultaneously accumulation and legitimation. The possibility of enhancing accumulation and maintaining legitimation clashes with the diverse socio-economic demands associated with the present agricultural production system and the general viability of the social structure as a whole.     

Agriculture and dualistic development: The case of Italy

The article illustrates the major features of the development of Italian agriculture from the middle of the nineteenth century to the present. It is argued that such development has been characterized by dualism. At the structural level dualism refers to the existence of a large number of small and very small farms, a limited number of medium-sized farms, and the presence of a very small segment of large farms that control the bulk of agricultural production and sales. Structural dualism in Italy is accompanied by regional dualism, which refers to the sharply different characteristics of the agriculture of the north and that of the south. In the northern regions the most productive and advanced farms are concentrated, while in the south smaller and less viable units are present. Dualism has created serious contradictions in Italian society, which have not been resolved with the further integration of the country's agricultural sector into the European Community.     

Human CHN1 mutations hyperactivate alpha2-chimaerin and cause Duane's retraction syndrome

Duane's retraction syndrome (DRS) is a complex congenital eye movement disorder caused by aberrant innervation of the extraocular muscles by axons of brainstem motor neurons. Studying families with a variant form of the disorder (DURS2-DRS), we have identified causative heterozygous missense mutations in CHN1, a gene on chromosome 2q31 that encodes alpha2-chimaerin, a Rac guanosine triphosphatase-activating protein (RacGAP) signaling protein previously implicated in the pathfinding of corticospinal axons in mice. We found that these are gain-of-function mutations that increase alpha2-chimaerin RacGAP activity in vitro. Several of the mutations appeared to enhance alpha2-chimaerin translocation to the cell membrane or enhance its ability to self-associate. Expression of mutant alpha2-chimaerin constructs in chick embryos resulted in failure of oculomotor axons to innervate their target extraocular muscles. We conclude that alpha2-chimaerin has a critical developmental function in ocular motor axon pathfinding.     

Distinct ensemble codes in hippocampal areas CA3 and CA1

The hippocampus has differentiated into an extensively connected recurrent stage (CA3) followed by a feed-forward stage (CA1). We examined the function of this structural differentiation by determining how cell ensembles in rat CA3 and CA1 generate representations of rooms with common spatial elements. In CA3, distinct subsets of pyramidal cells were activated in each room, regardless of the similarity of the testing enclosure. In CA1, the activated populations overlapped, and the overlap increased in similar enclosures. After exposure to a novel room, ensemble activity developed slower in CA3 than CA1, suggesting that the representations emerged independently.     

Bone mineral content of the third metacarpal bone in Quarter Horse foals from birth to one year of age

Dual photon absorptiometry (DPA) is a valid method for bone mineral content (BMC) evaluation, but there are no reports on the use of this technology in in vivo studies in the horse. The aim of the current study was to evaluate the changes of BMC of the third metacarpal bone (MC3) in vivo in foals during their first year of life using DPA. The BMC of the MC3 of 41 Quarter Horse foals was evaluated every 4 weeks during their first year of life by DPA using a bienergetic Gadolinium-153 (¹⁵³Gd) source. To the authors' knowledge, this is the first report of an in vivo study of BMC in foals using DPA by means of a bienergetic ¹⁵³Gd source. The results demonstrated a positive correlation of age, heart girth, and withers height with BMC of the MC3 independent of gender and an exponential behavior of the BMC increment along the first year of life. There was an effect of weaning associated with change in diet and stall confinement on BMC in foals weaned at age 17 weeks, but not in foals weaned at age between 19 and 24 weeks.