Citation: Ganivet E, Bloomberg M (2019) Towards rapid assessments of tree species diversity and structure in fragmented tropical forests: A review of perspectives offered by remotely-sensed and field-based data. Forest Ecology and Management, 432:40-53.

Nowadays, human activities are causing an important collapse in global biodiversity while also affecting the global climate considerably. Despite historical agreements on both biodiversity conservation and climate change, humanity keeps changing the face of the planet at an increasing rate. An undisputed factor in global change is the excessive and growing human consumption. On the other hand, it seems that linking humanity's environmental impact with population growth has been quite controversial in the international debate, as if, somehow, biodiversity loss and climate change were unconnected to it. To this purpose, this paper reviews (1) the impacts of continuing human population growth on global biodiversity and climate through the examples of food and energy production, (2) changing perceptions about population growth and (3) the potential solutions that could be used to address this issue. Despite not the only factor, the research reviewed in this paper highlights that continuing population growth plays a substantial global role in the destruction of biodiversity and in climate change, and this role urgently needs more attention in scientific, policy and public circles. Both unsustainable population levels and excessive consumption are part of the equation and must be addressed concurrently in developing and developed countries. Several non-coercive strategies are possible to address the population question, mostly through access to education and contraception, in order to empower women through the basic human right to have children by choice. In any case, although limiting population growth may not be the only solution required to fix current environmental problems, ignoring it is likely to hinder any ecologically sustainable future.

No abstract

In Tenerife (Canary Islands), the laurel forest is considered one of the most biodiverse ecosystems of the archipelago. This study aims at providing useful information about tree species strategies and their natural dynamics in order to improve understanding of the functioning of this ecosystem. The knowledge gained would be of great importance for laurel forest conservation, not only in the Canaries, but also in Madeira and the Azores. Our main research question is: 'Are the ecological groups of laurel forest tree species, described in earlier studies based exclusively on regeneration strategies, consistent with species functional traits, growth patterns and spatial distributions?' We used data from six 50 × 50 m permanent plots established in 1999 and remeasured in 2015, combined with information on twelve functional traits from newly produced data or extracted from previous studies. For each species we analyzed the abundance of seedlings/suckers, saplings and adults inside the permanent plots. Two ordination methods were used to assess multivariate differences in functional traits between species. Different mixed-effect models were tested to investigate effects of sites, individual tree size and competition on tree growth rates. Finally we analyzed the spatial distribution of both saplings and adults and their interaction within the six permanent plots. Our results were consistent with a classification of species into different ecological groups based on (1) their shade-tolerance: light-demanding vs. shade-tolerant species and (2) their reproductive strategies: sexual (i.e. seedlings), asexual (i.e. suckers) or both. These differences between light-demanding vs. shade-tolerant and/or seedling-producing species vs. sucker-producing species were consistently observed across the species functional traits, growth patterns and spatial distributions. Only one species, Viburnum rigidum Vent., presented singularities compared with its previously established group. Because V. rigidum is mostly an understory species, we proposed to add a third aspect to the classification scheme: understory vs. canopy species. This led to a total of six ecological groups within fourteen laurel forest tree species. Finally, this study also showed that the Tenerife laurel forest is still maturing and becoming richer in species, which outlines the importance of its preservation.

Understanding intra‐specific variation in climate sensitivity could improve the prediction of tree responses to climate change. We attempted to identify the degree of genetic control of tree phenology and growth of trembling aspen (Populus tremuloides Mchx.) in a natural stand of this species in northwestern Quebec. We mapped and genotyped 556 aspen trees growing within the plot, using seven nuclear microsatellite loci for clone identification. We selected 13 clones (n of trees per clone >5, in total 350 trees) and evaluated the explanatory power of clone identity in (a) variability of spring leaf phenology and (b) short‐ and long‐term growth responses. The clone's identity explained 43% of the variability in spring leaf phenology, between 18% and 20% of variability in response to monthly climate variables significantly affecting growth, between 8% and 26% of growth response to insect outbreaks, and 12% in the long‐term growth rates. Strong clonal control of aspen phenology and moderate control of growth responses to monthly weather do not result in an equally large impact on long‐term growth rates. The result suggests an important role of environmental extremes and within community interactions as factors averaging aspen growth performance at the stand level.