Roadless wilderness area determines forest elephant movements in the Congo Basin

A dramatic expansion of road building is underway in the Congo Basin fuelled by private enterprise, international aid, and government aspirations. Among the great wilderness areas on earth, the Congo Basin is outstanding for its high biodiversity, particularly mobile megafauna including forest elephants (Loxodonta africana cyclotis). The abundance of many mammal species in the Basin increases with distance from roads due to hunting pressure, but the impacts of road proliferation on the movements of individuals are unknown. We investigated the ranging behaviour of forest elephants in relation to roads and roadless wilderness by fitting GPS telemetry collars onto a sample of 28 forest elephants living in six priority conservation areas. We show that the size of roadless wilderness is a strong determinant of home range size in this species. Though our study sites included the largest wilderness areas in central African forests, none of 4 home range metrics we calculated, including core area, tended toward an asymptote with increasing wilderness size, suggesting that uninhibited ranging in forest elephants no longer exists. Furthermore we show that roads outside protected areas which are not protected from hunting are a formidable barrier to movement while roads inside protected areas are not. Only 1 elephant from our sample crossed an unprotected road. During crossings her mean speed increased 14-fold compared to normal movements. Forest elephants are increasingly confined and constrained by roads across the Congo Basin which is reducing effective habitat availability and isolating populations, significantly threatening long term conservation efforts. If the current road development trajectory continues, forest wildernesses and the forest elephants they contain will collapse

Long-term collapse in fruit availability threatens Central African forest megafauna

Afrotropical forests host many of the world’s remaining megafauna, but even here they are confined to areas where direct human influences are low. We use a rare long-term dataset of tree reproduction and a photographic database of forest elephants to assess food availability and body condition of an emblematic megafauna species at Lopé National Park, Gabon. We show an 81% decline in fruiting over a 32-year period (1986-2018) and an 11% decline in body condition of fruit-dependent forest elephants from 2008-2018. Fruit famine in one of the last strongholds for African forest elephants should raise concern for the ability of this species and other fruit-dependent megafauna to persist in the long-term, with consequences for broader ecosystem and biosphere functioning

MASTREE+: Time-series of plant reproductive effort from six continents.

Significant gaps remain in understanding the response of plant reproduction to environmental change. This is partly because measuring reproduction in long-lived plants requires direct observation over many years and such datasets have rarely been made publicly available. Here we introduce MASTREE+, a data set that collates reproductive time-series data from across the globe and makes these data freely available to the community. MASTREE+ includes 73,828 georeferenced observations of annual reproduction (e.g. seed and fruit counts) in perennial plant populations worldwide. These observations consist of 5971 population-level time-series from 974 species in 66 countries. The mean and median time-series length is 12.4 and 10 years respectively, and the data set includes 1122 series that extend over at least two decades (≥20 years of observations). For a subset of well-studied species, MASTREE+ includes extensive replication of time-series across geographical and climatic gradients. Here we describe the open-access data set, available as a.csv file, and we introduce an associated web-based app for data exploration. MASTREE+ will provide the basis for improved understanding of the response of long-lived plant reproduction to environmental change. Additionally, MASTREE+ will enable investigation of the ecology and evolution of reproductive strategies in perennial plants, and the role of plant reproduction as a driver of ecosystem dynamics

Sélection de l'habitat et organisation sociale de l'éléphant de forêt, Loxodonta africana cyclotis (Matschie 1900), au Gabon

L éléphant de forêt africain se différencie de l éléphant de savane par plusieurs caractères morphologiques, écologiques et moléculaires. Contrairement à ce dernier, il a été très peu étudié, bien qu'il soit menacé par la chasse et la destruction de la forêt primaire. Nous avons entrepris une étude de la biologie de cet animal, en profitant de deux sites naturellement ouverts au sein de la grande forêt, à savoir une zone de savanes, marais et bosquets à la Lopé, et une clairière riche en sels minéraux à Langoué. À la Lopé, nous avons analysé le choix des habitats par les animaux en recensant les nouvelles fèces produites chaque mois sur des transects établis dans les quatre principaux milieux. La forêt à Marantaceae et les marais en savane sont les habitats les plus utilisés par la population locale, mais alternativement au cours de l année. L identification des individus sur un circuit standardisé montre que la savane attire presque exclusivement les femelles accompagnées de leurs jeunes et les jeunes mâles indépendants, en jouant probablement le rôle de zone de nourrissage. Cependant, le suivi de quatre femelles adultes par télémétrie GPS montre que, si la zone de savane est importante à l échelle de l année et des saisons, les animaux utilisent également les différents types de forêt, en effectuant des allers-retours entre ces deux types de milieux. La phénologie des arbres indique que les animaux utilisent les habitats de plus en plus ouverts à mesure que les fruits se raréfient en forêt. Par contre, deux femelles et deux mâles adultes, suivis par télémétrie GPS dans une région uniquement forestière à Langoué, effectuaient des déplacements entre deux zones fixes de leur domaine individuel : la clairière ou bai et une zone principale d alimentation. Le bai était surtout utilisé par la population résidente pour la consommation de sels minéraux, mais il servait aussi de lieu de rencontre entre individus, surtout les mâles adultes qui établissaient ainsi une hiérarchie entre eux. Les déplacements et les domaines vitaux des huit individus suivis sur les deux sites ont été comparés aux autres travaux effectués sur les éléphants de forêt et de savane. Chez cet animal, les associations entre femelles adultes sont peu fréquentes. En forêt, l unité sociale la plus stable est composée de la mère et son jeune dépendant; en savane elle groupe le plus souvent deux femelles adultes et leurs jeunes dépendants. Cela diffère donc de l organisation sociale de l'éléphant de savane d Afrique et de l'éléphant d AsieThe African forest elephant differs from the savannah elephant in many morphological, ecological and genetic characteristics; however, few studies have focussed on the forest elephant, despite it being threatened by hunting and the destruction of primary forest habitat. This study has investigated the habitat use of the forest elephant using two natural open areas in the centre of primary forest; an area of savannah, marsh and fragmented forest in Lopé National Park, and a clearing rich in salts and minerals in Ivindo National Park. Habitat choice by forest elephants in Lopé was measured using fresh dung-counts, monitored monthly on fixed transects in the four main habitat types. Marantaceae forest and savannah marshlands were the habitat types most frequently used by the local population, but alternately during the course of the year. Visual identification of individual elephants on a standardised circuit showed that the savannah attracted almost exclusively females accompanied by their young, and young solitary males, and probably acted as a feeding area. Data on the movements of four female adults, using GPS telemetry, indicated that although the savannah zone was important at the year and season level, the animals also used different types of forest, making trips between open and closed habitat. Studies of fruiting phenology indicated that animals used increasingly open habitat as forest fruit availability decreased. The monitoring of two female adults and two male adults by GPS telemetry in an entirely forested region of Ivindo National Park showed that these animals moved between two fixed areas of their individual home ranges; the clearing, or bai , and a principal feeding area. Langoué bai was mainly used by the resident population for the consumption of mineral salts, but also served as a meeting place, especially for the male adults who then established a hierarchy amongst themselves. The movements and the home ranges of eight individuals followed in Lopé and Ivindo NP was compared with previous studies on forest and savannah elephants. The forest elephants studied here exhibited less frequent meetings between female adults; in the forest the most stable social unit was composed of the mother and her young dependant, and in the savannah groups of two female adults and their dependants were more common. This therefore differs from the social organisation of the savannah elephant and the Indian elephantPARIS-Museum Hist.Naturelle (751052304) / SudocSudocFranceF