10 research outputs found
Bridging the extant and fossil record of planktonic foraminifera: implications for the Globigerina lineage
We conducted a morphometric study and wall texture analysis on extant and fossil specimens of the planktonic foraminifera Globigerina falconensis plexus. Our global data reveal morphological inconsistencies between fossil and extant populations. Our results are significant as G. falconensis is widely used in palaeoceanographic studies in conjunction with its sister taxon G. bulloides. Morphologically these two species are similar, with the main difference being the distinctive apertural lip present in G. falconensis. We selected cores covering the entire stratigraphic range of G. falconensis, from the early Miocene to current day, spanning sites from high latitudes in the North Atlantic Ocean and the southern Indian Ocean to sites in equatorial regions. The morphology found in the modern ocean is not consistent with the Miocene holotype of Globigerina falconensis Blow described from lower Miocene sediments in Venezuela. A more lobate morphology evolved in the late Miocene, thus, a new name is required for this morphotype, coexisting in the modern oceans with G. falconensis s.s. We thus describe the new morphospecies, G. neofalconensis for the more lobate forms which evolved in the late Miocene and inhabit the modern oceans. Additionally, we report a pseudocancellate wall texture present in the G. falconensis plexus. We use the molecular sequences from the PR2 database to explore the generic attribution of the G. falconensis lineage, confirming its close relationship with G. bulloides and its retention in the genus Globigerina
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Using satellite tracking to assess the use of protected areas and alternative roosts by Whooper and Bewick's Swans
Publication status: PublishedFunder: UK Department of Energy and Climate ChangeFunder: COWRIE LtdProtected areas are one of the major tools used in the conservation of biodiversity, but animals are unlikely always to remain within these human‐made boundaries. Understanding when and why species choose to leave protected areas can help us to improve the effectiveness of these management tools. Here, we investigate the use of protected and non‐protected areas by two migratory species undergoing rapid wintering population changes in northwest Europe: Whooper Swans Cygnus cygnus and Bewick's Swans Cygnus columbianus bewickii. Global positioning system tags were fitted to 15 Whooper Swans in winter 2008/09 and to 18 Bewick's Swans from winter 2013/14 to 2014/15 at the Ouse Washes Special Protection Area (an internationally important roost for wintering waterbirds) and on adjacent fields in southeast England. Here, swans feed on farmland during the day but return to designated reserves to roost at night, where they receive protection from predators and disturbance within managed roost habitats. When swans roost elsewhere at alternative sites, they may face more adverse conditions, and so understanding the extent and causes of the use of alternative roosts is important for swan conservation efforts. The alternative roosting proportion, defined as the proportion of nights spent outside protected reserves, was 0.237 for Bewick's Swans and challenging to quantify accurately for Whooper Swans. A generalized additive mixed model to model repeated measurements on individuals showed that the proportion of time that Bewick's Swans spent at alternative roosts correlated positively with river level and negatively with temperature. Competition and foraging flight distances are thought to drive these relationships, as swans seek access both to roost space and to nearby feeding habitats. Our findings improve our understanding of the environmental conditions under which migratory waterbirds may choose to roost outside protected areas.</jats:p
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Comments to "Persistent problems in the construction of matrix population models"
The Evolution of Morphospace in Phytophagous Scarab Chafers: No Competition - No Divergence?
<div><p>Body shape reflects species' evolution and mediates its role in the environment as it integrates gene expression, life style, and structural morphology. Its comparative analysis may reveal insight on what shapes shape, being a useful approach when other evidence is lacking. Here we investigated evolutionary patterns of body shape in the highly diverse phytophagous chafers (Scarabaeidae: Pleurosticti), a polyphagous group utilizing different parts of angiosperms. Because the reasons of their successful diversification are largely unknown, we used a phylogenetic tree and multivariate analysis on twenty linear measurements of body morphology including all major Pleurosticti lineages to infer patterns of morphospace covariation and divergence. The chafer's different feeding types resulted to be not distinguishable in the described morphospace which was largely attributed to large occupancy of the morphospace of some feeding types and to multiple convergences of feeding behavior (particularly of anthophagy). Low correlation between molecular and morphological rates of evolution, including significant rate shifts for some lineages, indicated directed selection within feeding types. This is supported by morphospace divergence within feeding types and convergent evolution in Australian Melolonthinae. Traits driving morphospace divergence were extremities and traits linked with locomotion behavior, but also body size. Being highly adaptive for burrowing and locomotion these traits showed major changes in the evolution of pleurostict scarabs. These activities also affected another trait, the metacoxal length, which is highly influenced by key innovations of the metacoxa (extended mesal process, secondary closure) particularly in one lineage, the Sericini. Significant shape divergence between major lineages and a lack of strong differentiation among closely related lineages indicated that the question about the presence or absence of competition-derived directed selection needs to be addressed for different time scales. Striking divergence between some sister lineages at their origin revealed strong driven selection towards morphospace divergence, possibly linked with resource partitioning.</p></div