The Implementation of Habitat Destruction Methods That Promote Native Survival Under Invasion

Controlling invasive alien species invasion and maintaining the survival of native species have attracted increasing attention, and habitat destruction can be used to achieve these aims. However, it remains unclear whether and how to promote the long-term survival of indigenous species facing invaders through the use of habitat destruction. In this study, we developed a spatially explicit simulation model and exposed invaders and residents from this model to habitat destruction with different properties. The results showed that (1) introducing habitat destruction could promote the long-term survival of native species facing invaders; however, the promoting effect of habitat destruction occurred only over a period of time after introduction, and habitat destruction substantially weakened indigenous species before that. (2) Intermediate levels of habitat destruction were the most beneficial to the protection of native species. (3) Even if not considering the proportion of destroyed habitats, introducing spatially dispersed habitat destruction at an earlier time and shortening the interval between two habitat destruction events were very beneficial to the protection of residents. These insights can help facilitate the protection of residents under invasion by adjusting the implementation method of habitat destruction.

Urban Pit-Building Insects Are Attracted to Walls for Multiple Reasons

Whereas most animals find urban habitats to be inferior to natural habitats, some “urban specialist” species thrive there. Wormlions present such an example. Common in Mediterranean cities, they cluster in thin layers of loose soil below man-made shelters. Wormlions are fly larvae that dig pit-traps in loose soil and hunt small arthropods. Our first aim was to determine whether wormlion pits accumulate next to walls. Wormlion pits were indeed closer to walls than expected by chance at most of the study sites. We examined possible factors behind this apparent preference, combining field observations and experiments, laboratory work, and theoretical analysis. We examined the effect of soil depth, particle size, shade, and prey abundance. Each factor provided a partial explanation for the wormlions’ proximity to walls, but none provided an overall explanation. We developed a spatially explicit simulation model, demonstrating under which conditions wall-adjacent positions are favored. Finally, we created artificial microhabitats, and placed wormlions either in the center or next to the wall. The wormlions in the center moved over longer distances than those next to the wall and did so more in the wall’s direction. The abundance of walls may help to explain the success of wormlions in urban habitats.

Habitat loss-induced tipping points in metapopulations with facilitation

Habitat loss is known to pervade extinction thresholds in metapopulations. Such thresholds result from a loss of stability that can eventually lead to collapse. Several models have been developed to understand the nature of these transitions and how are they affected by the locality of interactions, fluctuations, or external drivers. Most models consider the impact of grazing or aridity as a control parameter that can trigger sudden shifts, once critical values are reached. Others explore instead the role played by habitat loss and fragmentation. Here we consider a minimal model incorporating facilitation along with habitat destruction, with the aim of understanding how local cooperation and habitat loss interact with each other. An explicit mathematical model is derived, along with a spatially explicit simulation model. It is found that a catastrophic shift is expected for increasing levels of habitat loss, but the breakpoint dynamics becomes continuous when dispersal is local. Under these conditions, spatial patchiness is found and the qualitative change from discontinuous to continuous results from a universal behaviour found in a broad class of nonlinear ecological systems (Weissmann and Shnerb, 2014; Martin et al. PNAS (2015) E1828-E1836). Our results suggest that species exhibiting facilitation and displaying short-range dispersal will be markedly more capable of dealing with habitat destruction, also avoiding catastrophic tipping points.

The Urban Sprawl and Urban Planning in Haikou

Rapid urban development and dramatic change of landscape have been recently witnessed in the developing city Haikou in China as a result of rapid economic development. In this paper, Dinamica which was a spatially explicit simulation model of landscape dynamics were used to simulate the evolution of Haikou during the period of 1989 to 2012.They are expanding from exist city cell, around the city center, along the transportation line, and rural resident spot. According to the spatial occupation reality of Haikouin 1996 and 2008, the simulation accuracy is greater than 82% . Dinamica model is considere d a useful tool for urbanization research. And we found that residential land development tools such as the Public Residential City Development (PRCD) and the Housing Construction Facilitating Support (HCFS) in Haikou are working to prevent sprawl or facilitate it.

Elephants or onions? Paying for nature in Amboseli, Kenya

ABSTRACTTraditional grazing grounds near Amboseli National Park (Kenya) are being rapidly converted to cropland – a process that closes important wildlife corridors. We use a spatially explicit simulation model that integrates ecosystem dynamics and pastoral decision-making to explore the scope for introducing a ‘payments for ecosystem services’ scheme to compensate pastoralists for spillover benefits associated with forms of land use that are compatible with wildlife conservation. Our break-even cost analysis suggests that the benefits of such a scheme likely exceed its costs for a large part of the study area, but that ‘leakage effects’ through excessive stocking rates warrant close scrutiny.

Which mosaic? A landscape ecological approach for evaluating interactions between fire regimes, habitat and animals

The link between ‘fire mosaics’ and persistence of animal species is part of a prominent ecological/land management paradigm. This paradigm deals largely with the effects of fire on animals on the basis of individual events. The universality of the paradigm can be questioned on a variety of grounds, a major deficiency being the inability to deal with quantitative effects of recurrent fire (the fire regime). A conceptual model of fire-related habitat elements is proposed for exploration of a continuum of species/habitat/landscape/fire regime combinations. This approach predicts that the dependence of species on fire-mediated habitat heterogeneity will be highly variable and strongly context-dependent. A spatially explicit simulation model was used to examine the persistence of malleefowl (Leipoa ocellata) in a specific landscape/habitat context where dependence on fire-mosaics should be high. Results suggest that persistence of L. ocellata populations will be dependent on intervention using small patchy fires but that there is an optimum rate of intervention. Results were sensitive to spatial pattern of prescribed fire, landscape type (topography) and probability of wildfire. Underlying effects of the fire-interval distribution (the ‘invisible’ mosaic) on plant species and habitat account for these results. A management emphasis on species/landscape context and awareness of the ‘invisible’ mosaic is advocated.