DOWNLOAD PDF The Origins and Relationships of Lower Invertebrates Intestinal Microorganisms of Termites and Other Invertebrates (Soil Biology. Jan A Pechenik. This textbook is the most concise and readable invertebrates book in terms of detail and pedagogy (other texts do not offer boxed readings, a second color, end of chapter questions, or pronunciation guides). Add tags for "Biology of the invertebrates". Editorial Reviews. About the Author. Jan A. Pechenik is Professor of Biology at Tufts University, Biology of the Invertebrates - Kindle edition by Pechenik.
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The pattern of declining species richness with increasing latitude, obvious in the terrestrial realm, is controversial among marine invertebrates and conclusions depend on the taxon and geographic scale studied.
A latitudinal decline from the tropics to the Arctic was seen in shelf molluscs, while arthropods seem to show higher diversity in some Arctic areas compared with some non-Arctic areas. Due to the turbulent geological history with repeated glaciation events over the last 3. However, bryozoans contain more endemics than many other groups, possibly partly related to poor dispersal in this group.
The present-day invertebrate fauna in the Arctic is a mixture of species with different origins, where the majority have distributions reaching outside the Arctic, i.
By and large the Arctic Ocean is a sea of immigrants that have dispersed from adjacent oceans both in historical and in recent time. On the continental shelves the proportions of present-day Pacific and Atlantic species decrease with increasing distance from the Bering Strait and the NE Atlantic, respectively. Like other faunal elements in the Arctic, marine invertebrates are affected by climate warming. The most obvious effects will be on the fauna of the permanent ice sympagic fauna which will lose its habitat.
However, detecting effects in the other realms is difficult, mainly because there are only few time series data available. It is expected that the fauna with strong boreal influence may show perhaps temporarily increased diversity, due to a combination of anticipated increased food availability for the benthos and immigration of species adapted to warmer waters.
Signs of borealization are already seen in marginal areas of the Actic Ocean. Long-term estimates of climate change effects on diversity are challenging because of the complex interactions of changes on multiple levels of the Arctic system. It is recommended that conservation actions are targeted towards whole systems rather than individual species. Since system-focused conservation efforts typically focus on limited regions, we need to know more about diversity patterns at a high spatial resolution, in particular the distribution of Arctic endemics in order to conserve as many unique species as possible.
There is a demand for research to get a better understanding of the factors and processes that affect diversity. To achieve this, regional and taxonomic gaps need to be closed and time series are needed to address temporal dynamics and changes in biodiversity. However, since time is probably short before severe effects of climate change will appear, we cannot wait for a high frequency mapping of the whole Arctic.
Instead we suggest the establishment, or in some cases continuation, of time series monitoring at selected sites in species rich Arctic areas close to the major gateways, as well as in some areas distant from the gateways into the Arctic.
This corresponds broadly to the delineation of the Arctic waters made in Fig. We recognize, however, that the literature cited below does not always follow this delineation. The present invertebrate diversity in the Arctic Ocean area is the net result of many factors acting both in historical and recent time. Like in other systems on Earth, species diversity in the Arctic is influenced by nichebased factors, such as adaptation to different environmental conditions and by dispersal based factors, such as immigration from species pools.
The relative importance of these two types of factors is not always easy to disentangle and may vary with scale and the degree of connectivity to other ecosystems.
Niche-based factors like adaptation to different environmental conditions are likely to account for a significant part of biodiversity in the Arctic because it is far from homogeneous. In each of the three realms, invertebrate species inhabit a multitude of different habitats.
The pelagic realm contains downwelling or upwelling areas, frontal zones and polynyas with a varying degree of coupling with the benthic realm below. The recent permanent ice-cover in the Central Arctic and seasonal ice in the rest of Arctic act as a specific habitat for sea-ice associated life, and within the ice realm habitats vary from highly productive ice edge areas to more oligotrophic zones in brine channels in the ice, as well as the ice-water interface on the underside of the ice.
The sea floor contains considerable large scale topographic heterogeneity, for instance intertidal coastal areas, semi-enclosed fjords with fjord basins, estuaries of different sizes, an expanded shelf zone with a number of canyons Voronin, St.
Anna and inner isolated depressions like Novaya Zemlya Trench , and the deep sea with several basins separated by deep-sea ridges. At smaller scales, benthic areas contain different sediment habitats such as sand and mud as well as harder substrata like boulders and bedrocks. If so, we would expect a high total diversity in particular of Arctic shelf fauna relative to deep sea areas.
A conspicuous feature of the sea areas of the Arctic is the strong gradient in salinity, both horizontally from river mouths out into the open sea as well as vertically, from close to fresh near the surface to fully marine at depth. Hence, in addition to seasonal ice melt, salinity gradients are highly influenced by freshwater inputs from mainly the Russian rivers, but also the MacKenzie and Yukon rivers in the western part of the Arctic Ocean.
These large rivers together with smaller ones create estuarine systems of different spatial sizes which often harbor a peculiar set of species adapted to cold water of low salinity.
The area of most intensive fresh water impact is regarded as a specific zoogeographical unit Siberian brackish shallow province by Filatova Furthermore, different parts of the Arctic have different levels of productivity Michel, Chapter 14 , which also may affect diversity Currie Productive areas often have more species than unproductive areas, but the causal relationships are still unclear Currie et al.
The Arctic Ocean may be regarded as an open system where the strength of the connections with adjacent oceans has changed over the last 4 million years. Water currents facilitate dispersal from sub-Arctic and boreal parts of adjacent oceans, through the Fram Strait and the Barents Sea from the Atlantic, and the Bering Strait from the Pacific Ocean e.
While the connection with the Pacific has opened and closed over time due to varying sea levels, the deep Atlantic entrance has been widely open. At present, there is some 10 times more Atlantic water than Pacific water flowing into the Arctic Ocean Loeng et al.
In addition to habitat complexity and the importance of recent dispersal from adjacent oceans, the turbulent geological history has also been important in shaping present day diversity of Arctic invertebrates.
In the comparatively young Arctic Ocean, the evolutionary origin of marine invertebrates reflects a Pacific origin dating back to the opening of the Bering Strait 3.
Throughout most of the Tertiary, the Arctic Ocean region supported a temperate biota, and fully Arctic conditions developed only during the latest part of this period. Sea ice cover formed c. Over the last million years, a series of glaciation periods with intermittent de-glaciations has created an unstable environment with a series of extinction and immigration events shaping present day diversity. These extinction events are thought to have precluded extensive local evolution or endemism on the shelves Dunton Furthermore, events during the last 3.
As contended by Briggs , there is little evidence from the marine realm that invasions have decreased native diversity, but rather that they have added to the native diversity, resulting in an overall increased diversity.
A result of this major transfer was therefore likely an enrichment of the Northern Atlantic pool of species with Pacific species. This pool of species may be the source of immigration into the Arctic Ocean in recent time. Against this background we expect that invertebrate diversity in the Arctic Ocean has been shaped to a high degree by dispersal based factors like immigration and a low degree of endemism.
We expect the Arctic Ocean to be dominated by wide-range boreal species. In this respect, it is interesting to compare the degrees of endemism in the Arctic with those in the Antarctic, another cold region with similar glaciation history Krylov et al.
The ACC, formed in the Miocene, is the only current on Earth extending from the sea surface to the sea floor, unimpeded by any landmasses Hassold et al. Conquerors or exiles? Impact of interference competition among invasive Ponto-Caspian gammarideans on their dispersal rates.
Biological Invasions DOI First records of two formerly overlooked Ponto-Caspian amphipods from Turkey, Echinogammarus trichiatus Martynov, and Dikerogammarus villosus Sovinsky, Turkish Journal of Zoology doi Feeding preferences of an invasive Ponto-Caspian goby for native and non-native gammarid prey.
Attachment ability of two Ponto-Caspian amphipod species may promote their overland transport. Out of the Black Sea: phylogeography of the invasive killer shrimp across Europe. Molecular Biology Reports, — PDF Rewicz T. A co-invasive microsporidian parasite reduces the predatory behaviour of its invasive host Dikerogammarus villosus. Parasitology 2 : Freshwater Biology — Diseases of Aquatic Organisms PDF Rachalewski M.
Echinogammarus trichiatus Martynov, — a new Ponto-Caspian amphipod invader in Poland with remarks on other alien amphipods from the river Oder. Crustaceana 86 10 : Microsporidian disease of the invasive amphipod Dikerogammarus villosus and potentialities for its transfer to local invertebrate fauna.
Cryptic invasion of Baltic lowlands by freshwater amphipod of Pontic origin. Gammarus varsoviensis Jazdzewski, Amphipoda, Gammaridae — a long overlooked species in Ukrainian rivers. Fungi: Microsporidia infecting the invasive amphipod Dikerogammarus villosus: a potential emerging disease in European rivers.
Parasitology PDF request Konopacka A. Aquatic Invasions 4 4 : PDF Bacela K. Reproductive biology of Dikerogammarus haemobaphes - an invasive gammarid Crustacea: Amphipoda colonizing running waters in Central Europe.
Biological Invasions 11 9 : PDF request Grabowski M. Salinity-related distribution of alien amphipods in rivers provides refugia for native species. Factors influencing predatory behaviour in an invasive gammaridean species, Dikerogammarus villosus and some related species.
PDF request Bacela K. Dikerogammarus villosus Sowinsky, Crustacea, Amphipoda enters Vistula — the biggest river in the Baltic basin.