The birds communities functional structure dynamics in the ash individual consortia under the influence of the climatic factors annual dynamics

Abstract

The studying of the connections between the birds and consortia is impossible without their dynamics research. The amount of organisms that are part of the consortium is large enough and their significant part is active only for some year part, the full extent of the links detection is impossible without the seasonal dynamics analyses. The article is devoted to the bird communities in individual consortia of such edificator of the linden-ash-tree oak groves, as the ash (Fraxinus excelsior L.). This work material was collected in different seasons of 2004–2010 years in a linden-ash oak grove on the test plot No. 209 of the ecological profile of the NSC «Belgard Prisamar`e International Biospheric stationary», Novomoskovsk district, Dnepropetrovsk region. The individual consortia of 183 ash examples of three age conditions (virgins – virg, young generative – gl, mature and old generative individuals – g2–g3) were investigated. The ash consortia have in their composition topomorphs of the woodbirds, edge birds, and ubiquitous birds. Woodbirds are the dominant birds group. They completely dominate in the virginia ash consortia and significantly prevail over the ubiquitous on young generative trees. An edge birds group appears only on old and mature generative trees. Climamorphs are represented by year-round and seasonal bird species. The ratio of these two groups in consortia varies during the year, but in general, year-round bird species dominate. Therefore, the interaction system of the birds with ash has is quit stable. The virginal ash has seasonal species only in summer and autumn. The generative ashes of all the categories have the both climamorphe groups during the year. This indicates that a stable system of the birds with ash consortive interactions has been formed only with the fruiting beginning. The trophomorphs are the most diverse group of the morphs. Such biomorphs as zoophages, phytophages, omnivores are represented in the ash consortium. Within these biomorphs, second-order biomors were identified: seed-eaters, fruit-eaters, observers, sweepers, deep sweepers. The third order trophomorphs were also distinguished as the size links. The trophomorphs greatest variety was recorded for the young generative trees – 13 trophomorphs of the second and third orders. The mature and old generative trees have 12 trophomorphs. The virginal trees – only 2 trophomorphs. This is partly due to the neighboring tree species influence in the tree stand composition. It was found that the virgin trees have the lowest biomorphic diversity of the birds, and the generative trees have the highest one. This distinguishes ash from the other tree species. The reason of this is that the mature and old generative ash (g2–g3) has a crown located above the upper layer. The semi-open architecture of this tree crown is also facilitate to this. In such conditions birds don’t find enough places for their protection from predators, so they spend a little time on this tree, and don’t delay in its crown. The young generative ash crowns are within the upper and middle tree layers, so they have safer conditions for birds. The studies conducted in different seasons, also has found an interesting feature of the ash. Unlike other species, the ash is the least attractive for birds in the fall. In winter the birds visit this tree quite actively. The ash high fecundity and its seeds remaining on the tree branches in winter are the reason of this fact. As a result, some birds feed the ash tree fruits, while the other birds extract insects-phytophagous from it. The results of the research indicate that the ash is less attractive for the birds than the tired crown trees, such as oak, maple, linden. On the other hand, a significant part of the birds time budget on ash is spent for surveillance. Birds use ash as a place for review and control of their site. Therefore, ash can be recommended as an additional species in the artificial tree-stands creation.