Ecosystem functions in natural and anthropogenic ecosystems across the East African coastal forest landscape

Habitat identity and landscape configuration significantly shape species communities and affect ecosystem functions. The conservation of natural ecosystems is of particular relevance in regions where landscapes have already been largely transformed into farmland and where habitats suffer under resource exploitation. The spillover of ecosystem functions from natural ecosystems into farmland may positively influence agricultural productivity and human livelihood quality. We measured three proxies of ecosystem functioning: Pollinator diversity (using pan traps), seed dispersal (with a seed removal experiment), and predation (using dummy caterpillars). We assessed these ecosystem functions in three forest types of the East African dry coastal forest (Brachystegia forest, Cynometra forest, and mixed forest), as well as in adjoining farmland and in plantations of exotic trees (Eucalyptus mainly). We measured ecosystem functions at 20 plots for each habitat type, and along gradients ranging from the forest into farmland. We also recorded various environmental parameters for each study plot. We did not find significant differences of ecosystem functions when combining all proxies assessed, neither among the three natural forest types, nor between natural forest and plantations. However, we found trends for single ecosystem functions. We identified highest pollinator diversity along the forest margin and in farmlands. Vegetation cover and blossom density affected the level of predation positively. Based on our findings, we suggest that flowering gardens around housings and woodlots across farmland areas support ecosystem functioning and thus improve human livelihood quality. We conclude that levels of overall ecosystem functions are affected by entire landscapes, and high landscape heterogeneity, as found in our case, might blur potential negative effects and trends arising from habitat destruction and degradation.     

Evidence and hypothesis in biogeography

Evidence can provide support for or against a particular biogeographical hypothesis. Treating a hypothesis as if it were evidence or an empirical observation confounds many biogeographical analyses. We focus on two recent publications that address, in part, the evolution of the biota of Sulawesi, the large Indonesian island in the centre of the Indo‐Australian Archipelago. Many biogeographical explanations are hampered by invoking simple notions of mechanism or process – dispersal and vicariance – or constraints, such as dispersal from a centre of origin, and, in so doing, dismiss more complex geological phenomena such as emergent volcanoes within island chains or composite areas as irrelevant. Moreover, they do not search for, therefore never discover, biogeographical patterns that may better explain the distribution of biota through time.     

The bryophyte flora of northern Iturup (north-west Pacific): between the circumboreal and East Asian floristic regions

Introduction. The Kuril Islands Chain demarcates the boundary between the circumpolar and East Asian floras in the amphi-Pacific and is a trans-Oceanic migration route from warm-temperate insular East Asia to north-east Asia and Beringia. This paper reviews the flora of the northern part of Iturup Island in regards to its bryogeography and taxonomic diversity, as well as its relative position among other bryophyte floras of north-east and East Asia.

Methods. The paper uses morphological methods to identify the species composition and detrended correspondence analysis to identify the position of the northern Iturup Island in the system of local floras of the eastern, extra-tropical, Pacific.

Key results. The flora is closely related to the bryophyte floras of the southern Kurils and Hokkaido Island, but has been found to be distinctly distant from the ‘true’ cool-temperate East Asian floras, as well as from the boreal and hemiarctic floras of north-east Asia. Instead, the floras of the south Kurils and northern Hokkaido Island belong to a peculiar intermediate phytogeographic province that cannot be unambiguously placed in either the East Asian or circumboreal floristic regions. The hemiboreal character of the bryophyte flora of northern Iturup Island is in contrast to the general appearance of many of the dominant vegetation communities on the island, which are more characteristic of the hemiarctic.

Conclusion. There is no robust evidence to refer the bryophyte flora of northern Iturup either to the circumboreal or East Asian Floristic Region, the flora belongs to a unique intermediate province between the two regions.     

TAXONOMIC STATUS OF

Association of Cattle Egrets Bubulcus ibis with large herbivores is well documented, but there are few records of their association with large birds. Here we describe the first-known records of foraging interactions between Shoebill Balaeniceps rex and Cattle Egrets. The observations were made at the Malagarasi-Muyovozi Ramsar Site in western Tanzania. Small flocks of egrets approached and foraged within 5 m of a Shoebill, which was sometimes forced to move from its hunting pool and by doing so it likely flushed more prey for egrets. Interactions occurred almost exclusively in the driest months, which suggested that prey were more difficult to locate by egrets during this period. The Shoebill inhabits inaccessible swamps and is a rare species with low density throughout its range. It is therefore possible that egret–Shoebill associations, in addition to being infrequent and highly seasonal, may have gone unnoticed.     

A response to Gatali and Wallin (2015) Bird diversity in the savanna habitats of Akagera National Park,Rwanda, in the post-war recovery period

The paper ‘Bird diversity in the savanna habitats of Akagera National Park, Rwanda, in the post-war recovery period’ by Gatali and Wallin (Ostrich 86(3): 267–276, 2015) makes several claims for new species records for Akagera National Park and Rwanda. We found that Gatali and Wallin recorded several species considered very rare in Rwanda and new discoveries; these findings often contradicted the existing literature. We doubt the validity of 34 species records and we aim to demonstrate that these claims are mostly the result of misidentification or human error and consider that future researchers should use their findings with caution. Some findings around more common species may be validated through further studies and we encourage others to conduct fieldwork in Akagera National Park.     

Dating the Lower to Middle Paleolithic transition in the Levant: A view from Misliya Cave,Mount Carmel,Israel

The transition from the Lower to the Middle Paleolithic in the Levant is a crucial event in human evolution, since it may involve the arrival of a new human population. In the current study, we present thermoluminescence (TL) dates obtained from 32 burnt flints retrieved from the late Lower Paleolithic (Acheulo-Yabrudian) and Early Middle Paleolithic (Mousterian) layers of Misliya Cave, Mount Carmel, Israel. Early Middle Paleolithic industries rich in Levallois and laminar products were assigned mean ages ranging from ∼250 to ∼160 ka (thousands of years ago), suggesting a production of this industry during MIS 7 and the early part of MIS 6. The mean ages obtained for the samples associated with the Acheulo-Yabrudian (strengthened by an isochron analysis) indicate a production of this cultural complex ∼250 ka ago, at the end of MIS 8. According to the Misliya TL dates, the transition from the Lower to the Middle Paleolithic in the site took place at the limit MIS 8/7 or during the early part of MIS 7. The dates, together with the pronounced differences in lithic technology strongly suggest the arrival of a new population during this period.     

Historical climate‐human‐ecosystem interaction in East Africa: a review

The palaeoecological visibility of historical human impact on natural ecosystems in tropical East Africa is strongly impeded by an overriding dominant signature of climate change at decadal‐to‐millennial time scales. Better knowledge of the relative magnitude and timing of present and past human impact and climate variability is, however, instrumental to properly assess the resilience, and recovery potential, of East Africa's natural ecosystems. Here, we briefly review comprehensive previous attempts to assess past ecosystem responses to climate change and human impact. We further discuss some key issues of climate‐human‐ecosystem relationships in a multidisciplinary framework and address some future challenges and outcomes, which may pave the way to a better understanding of past climate‐human‐ecosystem interaction‐ in tropical Africa.