Estimating vegetation cover from high-resolution satellite data to assess grassland degradation in the Georgian Caucasus

In the Georgian Caucasus, unregulated grazing has damaged grassland vegetation cover and caused erosion. Methods for monitoring and control of affected territories are urgently needed. Focusing on the high-montane and subalpine grasslands of the upper Aragvi Valley, we sampled grassland for soil, rock, and vegetation cover to test the applicability of a site-specific remote-sensing approach to observing grassland degradation. We used random-forest regression to separately estimate vegetation cover from 2 vegetation indices, the Normalized Difference Vegetation Index (NDVI) and the Modified Soil Adjusted Vegetation Index (MSAVI2), derived from multispectral WorldView-2 data (1.8 m). The good model fit of R2 = 0.79 indicates the great potential of a remote-sensing approach for the observation of grassland cover. We used the modeled relationship to produce a vegetation cover map, which showed large areas of grassland degradation

Impact scores of invasive plants are biased by disregard of environmental co-variation and non-linearity

Prioritisation of high-impact species is becoming increasingly important for management of introduced species (‘neobiota’) because of their growing number of which, however, only a small fraction has substantial impacts. Impact scores for prioritising species may be affected by the type of effect model used. Recent studies have shown that environmental co-variation and non-linearity may be significant for effect models of biological invasions. Here, we test for differences in impact scores between simple and complex effect models of three invasive plant species (Heracleum mantegazzianum, Lupinus polyphyllus, Rosa rugosa). We investigated the effects of cover percentages of the invasive plants on species richness of invaded communities using both simple linear effect models (‘basic models’) and more complex linear or nonlinear models including environmental co-factors (‘full models’). Then, we calculated impact scores for each invasive species as the average reduction of species richness predicted by basic and full effect models. All three non-native species had negative effects on species richness, but the full effect models also indicated significant influence of habitat types. Heracleum mantegazzianum had uniform linear effects in all habitats, while effects of L. polyphyllus interacted strongly with habitat type, and R. rugosa showed a marked non-linear relationship. Impact scores were overestimated by basic effect models for H. mantegazzianum and R. rugosa due to disregard of habitat effects and non-linearity, respectively. In contrast, impact of L. polyphyllus was underestimated by the basic model that did not account for the strong interaction of invader cover and habitat type. We conclude that simple linear models will often yield inaccurate impact scores of non-native species. Hence, effect models should consider environmental co-variation and, if necessary, non-linearity of the effects of biological invasions on native ecosystems

Un campus universitaire dans la zone péri-urbaine d'Accra (Ghana) comme un refuge pour les espèces de forêt sèche

Die Valley-View Universität (VVU) ist eine private Universität, die in der Trockenwaldzone der Accra Plains liegt; einem Gebiet, welches sehr stark von Urbanisierung und Zersiedlung betroffen ist. Das Campus-Gelände umfasst ca. 105 ha. Beachtliche Flächen davon sind bislang nicht bebaut und noch mit Savannengebüschen bedeckt. Im Jahre 2002 hat sich die VVU zum Ziel gesetzt, die erste "ökologische Universität" Afrikas zu werden. Im Rahmen zweier Projekte wurden bedeutende Fortschritte im Abwassersystem und der Wasserversorgung sowie beim Bau energiesparender Gebäude und der ökologischen Landwirtschaft erzielt. Die weitere konzeptionelle Entwicklung des Campus wurde in einem detaillierten "Ökologischen Masterplan" festgehalten. In diesem Rahmen führten wir eine floristische Bestandserhebung in den Savannengebüschen durch und fanden mehr als 100 Pflanzenarten. In der Mehrzahl handelte es sich dabei um den Artenpool der für die Region typischen Kombination aus Trockenwald- und Savannenarten. Da die verbliebenen Reste von Trockenwäldern und Savannengebüschen in den Accra Plains zunehmend durch (ungeplante) Zersiedlung und Überbeweidung bedroht sind, hat die VVU-Verwaltung sich bereit erklärt, die artenreichen Gebüsche auf dem Campus-Gelände zu erhalten. Sie leistet damit einen wertvollen Beitrag zu einer etwas nachhaltigeren Entwicklung der Region.Valley View University (VVU) is a private university located within the dry forest zone of the Accra plains; an area strongly affected by urban sprawl. The campus covers approx. 105 ha. Considerable portions of it are yet undeveloped and covered with savannah thickets. In 2002, the university has committed itself to become Africa's first "ecological university". In the context of two projects, substantial improvements have been made in terms of sanitation, water supply, energy-saving buildings and organic agriculture. The further development of the campus was designed in a detailed "ecological masterplan". In this context, we carried out a floristic inventory of the savannah thickets and found more than 100 plant species; the majority of which represent the species pool of the unique mixture of dry forest and savannah thicket species, which is typical for the region. As the remainder of dry forests and savannah thickets in the Accra plains become increasingly threatened by urban sprawl and overgrazing, the VVU administration has agreed to preserve the species-rich thickets. This is a valuable contribution to a more sustainable development of the region.Valley View University (VVU) est une université privée située dans la zone de forêt sèche des plaines d'Accra; une zone fortement affectée par l'expansion urbaine. Le campus couvre approximativement 105 ha. Des parties importantes de celui-ci sont encore peu développées et couvertes de fourrées de savane. En 2002, l'université s'est engagée à devenir la première "université écologique" d'Afrique. Dans le cadre de deux projets, des améliorations substantielles ont été apportées en matière d'assainissement, d'approvisionnement en eau, de bâtiments peu consommateurs d'énergie et d’agriculture biologique. Le développement ultérieur du campus a été conçu dans un "schéma directeur écologique" détaillé. C'est dans ce contexte, que nous avons réalisé un inventaire floristique des fourrées de savane et avons trouvé plus de 100 espèces végétales; dont la majorité représente le pool est composé uniquement d'espèces de forêt sèche et de fourrées de savane, typiques à la région. Comme le reste des forêts sèches et des fourrés de savane des plaines d'Accra deviennent de plus en plus menacées par l'expansion urbaine et le surpâturage, l'administration VVU a accepté de préserver les fourrés riches en espèces. C'est une précieuse contribution à un développement plus durable de la région

Land Cover Changes (1963–2010) and Their Environmental Factors in the Upper Danube Floodplain

To analyze the changes in the Upper Danube Floodplain, we used aerial photos to quantify the change of landscape pattern from 1963 to 2010. We focused on typical floodplain habitats, i.e., riparian forest and floodplain grassland. We used landscape metrics and transformation matrix to explore changes in land cover structure and composition. The active floodplain experienced increasing fragmentation from 1963 to 2010. Despite an increase of aggregation, riparian forest suffered a 2.3% area loss from 1995 to 2010. Arable land in the active floodplain declined by 28.5%, while its patch size significantly increased. Elevation, distance to river and soil quality were the most relevant environmental factors for the land cover change in the floodplain. Higher soil quality or longer distance to river led to an increase of conversion from grassland into arable land; grassland patches with poorer soil quality were likely to change into riparian forest; riparian forest closer to the river and with a lower height above mean water level tended to remain stable. This comprehensive understanding of historical land cover change and environmental factors is needed for the enhancement of landscape functions and sustainable development in the floodplain

Memantine treatment does not affect compulsive behavior or frontostriatal connectivity in an adolescent rat model for quinpirole-induced compulsive checking behavior

RATIONALE: Compulsivity often develops during childhood and is associated with elevated glutamate levels within the frontostriatal system. This suggests that anti-glutamatergic drugs, like memantine, may be an effective treatment. OBJECTIVE: Our goal was to characterize the acute and chronic effect of memantine treatment on compulsive behavior and frontostriatal network structure and function in an adolescent rat model of compulsivity. METHODS: Juvenile Sprague-Dawley rats received repeated quinpirole, resulting in compulsive checking behavior (n = 32; compulsive) or saline injections (n = 32; control). Eight compulsive and control rats received chronic memantine treatment, and eight compulsive and control rats received saline treatment for seven consecutive days between the 10th and 12th quinpirole/saline injection. Compulsive checking behavior was assessed, and structural and functional brain connectivity was measured with diffusion MRI and resting-state fMRI before and after treatment. The other rats received an acute single memantine (compulsive: n = 12; control: n = 12) or saline injection (compulsive: n = 4; control: n = 4) during pharmacological MRI after the 12th quinpirole/saline injection. An additional group of rats received a single memantine injection after a single quinpirole injection (n = 8). RESULTS: Memantine treatment did not affect compulsive checking nor frontostriatal structural and functional connectivity in the quinpirole-induced adolescent rat model. While memantine activated the frontal cortex in control rats, no significant activation responses were measured after single or repeated quinpirole injections. CONCLUSIONS: The lack of a memantine treatment effect in quinpirole-induced compulsive adolescent rats may be partly explained by the interaction between glutamatergic and dopaminergic receptors in the brain, which can be evaluated with functional MRI